NASA officials declared the Artemis I mission successful in late 2021, and it's hard to argue with that assessment. The Space Launch System rocket and Orion spacecraft performed nearly flawlessly on an unpiloted flight that took it around the Moon and back to Earth, setting the stage for the Artemis II, the program's first crew mission.

But one of the things engineers saw on Artemis I that didn't quite match expectations was an issue with the Orion spacecraft's heat shield. As the capsule streaked back into Earth's atmosphere at the end of the mission, the heat shield ablated, or burned off, in a different manner than predicted by computer models.

More of the charred material than expected came off the heat shield during the Artemis I reentry, and the way it came off was somewhat uneven, NASA officials said. Orion's heat shield is made of a material called Avcoat, which is designed to burn off as the spacecraft plunges into the atmosphere at 25,000 mph (40,000 km per hour). Coming back from the Moon, Orion encountered temperatures up to 5,000° Fahrenheit (2,760° Celsius), hotter than a spacecraft sees when it reenters the atmosphere from low-Earth orbit.

Despite heat shield issue, the Orion spacecraft safely splashed down in the Pacific Ocean. Engineers discovered the uneven charring during post-flight inspections.

No answers yet

Amit Kshatriya, who oversees development for the Artemis missions in NASA's exploration division, said Friday that the agency is still looking for the root cause of the heat shield issue. Managers want to be sure they understand the cause before proceeding with Artemis II, which will send astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen on a 10-day flight around the far side of the Moon.

This will be the first time humans fly near the Moon since the last Apollo mission in 1972. In January, NASA announced a delay in the launch of Artemis II from late 2024 until September 2025, largely due to the unresolved investigation into the heat shield issue.

"We are still in the middle of our investigation on the performance of the heat shield from Artemis I," Kshatriya said Friday in a meeting with a committee of the NASA Advisory Council.

Engineers have performed sub-scale heat shield tests in wind tunnels and arc jet facilities to better understand what led to the uneven charring on Artemis I. "We’re getting close to the final answer in terms of that cause," Kshatriya said.

NASA officials previously said it is unlikely they will need to make changes to the heat shield already installed on the Orion spacecraft for Artemis II, but haven't ruled it out. A redesign or modifications to the Orion heat shield on Artemis II would probably delay the mission by at least a year.

Instead, engineers are analyzing all of the possible trajectories the Orion spacecraft could fly when it reenters the atmosphere at the end of the Artemis II mission. On Artemis I, Orion flew a skip reentry profile, where it dipped into the atmosphere, skipped back into space, and then made a final descent into the atmosphere, sort of like a rock skipping across a pond. This profile allows Orion to make more precise splashdowns near recovery teams in the Pacific Ocean and reduces g-forces on the spacecraft and the crew riding inside. It also splits up the heat load on the spacecraft into two phases.

The Apollo missions flew a direct reentry profile. There is also a reentry mode available called a ballistic entry, in which the spacecraft would fly through the atmosphere unguided.

The charred material began flying off the heat shield in the first phase of the skip reentry. Engineers are looking at how the skip reentry profile affected the performance of the Orion heat shield. NASA wants to understand how the Orion heat shield would perform during each of the possible reentry trajectories for Artemis II.

"What we have the analysis teams off doing is saying, 'OK, independent of what the constraints are going to be, what can we tolerate?" Kshatriya said.

Once officials understand the cause of the heat shield charring, engineers will determine what kind of trajectory Artemis II needs to fly on reentry to minimize risk to the crew. Then, managers will look at building what NASA calls flight rationale. Essentially, this is a process of convincing themselves the spacecraft is safe to fly.

"When we stitch it all together, we’ll either have flight rationale or we won’t," Kshatriya said.

Assuming NASA approves the flight rationale for Artemis II, there will be additional discussions about how to ensure Orion heat shields are safe to fly on downstream Artemis missions, which will have higher-speed reentry profiles as astronauts return from landings on the Moon.

In the meantime, preparations on the Orion spacecraft for Artemis II continue at NASA's Kennedy Space Center. The crew and service modules for Artemis II were mated together earlier this year, and the entire Orion spacecraft is now inside a vacuum chamber for environmental testing.

Welcome to Edition 6.41 of the Rocket Report! As I finish up this edition I'm listening to the post-Flight Readiness Review news conference for Boeing's Crew Flight Test. It sounds like everything remains on track for a launch attempt on May 6, at 10:34 pm ET. It's exciting to see this important milestone for Boeing and the US human spaceflight program so near to hand.

As always, we welcome reader submissions, and if you don't want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

Shetland spaceport advancing toward launch. SaxaVord Spaceport in Scotland is on track to launch the United Kingdom’s first vertical rocket into orbit, the BBC reports. The Civil Aviation Authority has granted a range license to the Scottish spaceport, which will allow the company to control the sea and airspace during launch. Previously, the site received a spaceport license in December 2023. Ambitiously, the facility aims to launch up to 30 rockets every year.

From Germany to Scotland with love ... "This is a vital component in our preparations for launch," said Frank Strang, chief executive of SaxaVord Spaceport. "As Western Europe’s only fully licensed vertical launch spaceport, we are now preparing to make more space history with the beginning of orbital launch operations well underway.” Germany-based rocket manufacturer Rocket Factory Augsburg could be the first to launch an orbital mission from Shetland later this year. (submitted by Ken the Bin)

Rocket Lab launches 5th Electron this year. Rocket Lab launched a South Korean smallsat and a NASA solar sail experiment on the company’s fifth flight of the year on Tuesday, Space News reports. NEONSAT-1, the primary payload of the mission, is an imaging satellite with a mass of about 100 kilograms. The spacecraft is part of a constellation of 11 spacecraft called New-space Earth Observation Satellite Constellation for National Safety, with the other 10 to be launched by South Korea’s Nuri rocket in 2026 and 2027.

Better get busy ... This was the first Electron launch in more than a month after a mission for the National Reconnaissance Office on March 21 from Rocket Lab’s Launch Complex 2 in Virginia. Company executives said in an earnings call in February that the company has 22 Electron launches planned for the year, two of which are of its HASTE suborbital version. That would be an impressive total if Rocket Lab can achieve it. (submitted by Jay500001)

PLD Space has raised 120 million euros. The Spanish launch startup revealed this week that it has raised 120 million euros to date, providing the funding needed to launch its orbital Miura 5 rocket by the end of 2025. Last October the company's smaller, suborbital Miura 1 rocket made what the company characterized as a "successful" test flight, reaching an altitude of 46 km. By my very rough rule of thumb, a launch company must have at least $100 million in funding to have a fighting chance to reach orbit.

Building new buildings ... The Miura 5 vehicle is intended to have a capacity of up to 250 kg in low-Earth orbit. The new funding will mainly be used for the expansion of PLD Space's infrastructure, increasing the size of its facilities from 169,000 to 834,000 square meters. The company also plans to begin building a launch site for the Miura 5 rocket in Kourou, French Guiana, later this year. (submitted by Ken the Bin and EllPeaTea)

SpaceX lands 300th Falcon booster. With the launch of a Starlink mission on Tuesday evening and subsequent return of the Falcon 9 first stage, SpaceX recorded its 300th successful booster landing. In the Falcon fleet's lifetime, SpaceX has now landed about 85 percent of the Falcon rockets it has launched, Ars reports. These days, more than 90 percent of all its missions launch on previously flown boosters. So, rocket recycling is totally a thing.

Saving a lot of metal ... Landing 300 rockets means SpaceX has preserved 2,700 Merlin rocket engines. In round numbers, the dry mass of a Falcon 9 first stage is about 50 metric tons, so the landing of all these rockets has prevented 15,000 metric tons of metal and other materials from being dumped into the oceans. To put this number further into perspective, only a handful of rockets have ever launched more than 300 times, and they are all Russian.

China launches astronaut mission. A Long March 2F rocket lifted off from the Jiuquan Satellite Launch Center in the Gobi Desert on Thursday, carrying the Shenzhou 18 spacecraft and its three-person crew into orbit, Space.com reports. Shenzhou 18 is commanded by Ye Guangfu, 43, who was part of the Shenzhou 13 mission three years ago. Fighter pilots Li Cong, 34, and Li Guangsu, 36, both spaceflight rookies, make up the rest of the crew.

A change in control ... The three will spend around six months in space. Their spacecraft is scheduled to reach the Tiangong space station 6.5 hours after launch. The trio will be greeted aboard the orbital outpost by Tang Hongbo, Tang Shengjie, and Jiang Xinlin, who make up the Shenzhou 17 crew. The latter three will soon complete their six months in orbit. (submitted by Ken the Bin and EllPeaTea)

China on track for 2030 lunar landing. China is on target to reach its goal of putting its astronauts on the Moon before the end of the decade, according to the country’s human spaceflight agency. Officials with the China Manned Space Engineering Office provided a rare update on the crewed lunar program during a press conference at Jiuquan spaceport on April 24, Space News reports. Two Long March 10 lunar variant rockets will separately launch Mengzhou and three astronauts and the Lanyue lander.

Hardware in work ... The pair will then perform a lunar orbit rendezvous and docking ahead of descent to the lunar surface. Two astronauts will spend six hours on the lunar surface before rejoining their colleague in lunar orbit and returning to Earth. “The program development for major flight products, including the Long March 10 rocket, the Mengzhou crew spacecraft, the lunar lander Lanyue and the lunar landing suits, are all complete,” said Lin Xiqiang, deputy director of CMSEO. “Their prototype production and tests are in full swing.” I'm not convinced they'll make 2030, but China's simple architecture gives them a chance. (submitted by EllPeaTea)

NASA considering changes to Artemis III. Although NASA is unlikely to speak about it publicly any time soon, the space agency is privately considering modifications to its Artemis plan to land astronauts on the surface of the Moon later this decade, Ars reports. Multiple sources confirmed that NASA is studying alternatives to the planned Artemis III landing of two astronauts on the Moon, nominally scheduled for September 2026, due to concerns about hardware readiness and mission complexity.

Saving an ICPS stage ... Under one of the options, astronauts would launch into low-Earth orbit inside an Orion spacecraft and rendezvous there with a Starship vehicle, separately launched by SpaceX. During this mission, similar to Apollo 9, a precursor to the Apollo 11 lunar landing, the crew would validate the ability of Orion and Starship to dock and test habitability inside Starship. One benefit of this mission profile is that NASA could "save" an upper stage for the SLS rocket and use it on the subsequent lunar landing mission while also buying down some risk.

Boeing will cut SLS workforce. Last week, senior Boeing officials leading the Space Launch System program convened an all-hands meeting for the more than 1,000 employees who work on the rocket. They announced that there would be significant cuts to the program, Ars reports. In a statement provided to Ars, a Boeing spokesperson confirmed the cuts: "Due to external factors unrelated to our program performance, Boeing is reviewing and adjusting current staffing levels on the Space Launch System program."

Cites 'external factors' ... The Boeing statement did not say so, but sources told Ars that the cuts may eventually amount to hundreds of employees. They will be spread across the company's rocket facilities in Alabama, Louisiana, and Florida, primarily. When Boeing cites "external factors," it is referring to the slipping timelines for NASA's Artemis Program. Although the SLS rocket will be ready for the current schedule, barring a catastrophe, the other elements are in doubt. For Artemis II, NASA still has not cleared a heat shield issue with the Orion spacecraft. The lunar lander and spacesuits will not be ready for Artemis III.

New Glenn to debut in September? For the time being at least, NASA is expecting a Mars smallsat mission to launch in late September on Blue Origin's New Glenn rocket, Space News reports. Nick Benardini, NASA’s planetary protection officer, listed a September 29 date for the launch of the Escape and Plasma Acceleration and Dynamics Explorers (ESCAPADE) mission during a Committee on Space Research meeting this week.

A much-anticipated launch ... That is the most precise date yet offered for the mission. Blue Origin itself has not announced a formal date for the first New Glenn launch beyond the company’s expectation that it will take place this year after several years of delays. Among the pacing items for this mission are seven BE-4 engines, which will power New Glenn's first stage. A handful of sources inside Blue Origin believe the company is making credible progress toward a launch attempt this year. (submitted by Ken the Bin)

Next three launches

April 28: Falcon 9 | Galileo satellites | Kennedy Space Center, Florida | 00:34 UTC

April 28: Falcon 9 | Starlink 6-54 | Cape Canaveral Space Force Station, Florida | 21:50 UTC

May 2: Falcon 9 | Starlink 6-55 | Cape Canaveral Space Force Station, Florida | 01:43 UTC

Historical accounts vary about how the Greek philosopher Plato died: in bed while listening to a young woman playing the flute; at a wedding feast; or peacefully in his sleep. But the few surviving texts from that period indicate that the philosopher was buried somewhere in the garden of the Academy he founded in Athens. The garden was quite large, but archaeologists have now deciphered a charred ancient papyrus scroll recovered from the ruins of Herculaneum, indicating a more precise burial location: in a private area near a sacred shrine to the Muses, according to Constanza Millani, director of the Institute of Heritage Science at Italy's National Research Council.

As previously reported, the ancient Roman resort town Pompeii wasn't the only city destroyed in the catastrophic 79 AD eruption of Mount Vesuvius. Several other cities in the area, including the wealthy enclave of Herculaneum, were fried by clouds of hot gas called pyroclastic pulses and flows. But still, some remnants of Roman wealth survived. One palatial residence in Herculaneum—believed to have once belonged to a man named Piso—contained hundreds of priceless written scrolls made from papyrus, singed into carbon by volcanic gas.

The scrolls stayed buried under volcanic mud until they were excavated in the 1700s from a single room that archaeologists believe held the personal working library of an Epicurean philosopher named Philodemus. There may be even more scrolls still buried on the as-yet-unexcavated lower floors of the villa. The few opened fragments helped scholars identify various Greek philosophical texts, including On Nature by Epicurus and several by Philodemus himself, as well as a handful of Latin works. But the more than 600 rolled-up scrolls were so fragile that it was long believed they would never be readable, since even touching them could cause them to crumble.

Scientists have brought all manner of cutting-edge tools to bear on deciphering badly damaged ancient texts like the Herculaneum scrolls. For instance, in 2019, German scientists used a combination of physics techniques (synchrotron radiation, infrared spectroscopy, and X-ray fluorescence) to virtually "unfold" an ancient Egyptian papyrus.

Brent Searles' lab at the University of Kentucky has been working on deciphering the Herculaneum scrolls for many years. He employs a different method of "virtually unrolling" damaged scrolls, using digital scanning with micro-computed tomography—a noninvasive technique often used for cancer imaging—with segmentation to digitally create pages, augmented with texturing and flattening techniques. Then they developed software (Volume Cartography) to virtually unroll the scroll.

The older Herculaneum scrolls were written with carbon-based ink (charcoal and water), so one would not get the same fluorescing in the CT scans, but the scans can still capture minute textural differences indicating those areas of papyrus that contained ink compared to the blank areas, and it's possible to train an artificial neural network to do just that.

This latest work is under the auspices of the "GreekSchools" project, funded by the European Research Council, which began three years ago and will continue through 2026. This time around, scholars have used infrared, ultraviolet optical imaging, thermal imaging, tomography, and digital optical microscopy as a kind of "bionic eye" to examine Philodemus' History of the Academy scroll, which was also written in carbon-based ink. Nonetheless, they were able to extract over 1,000 words, approximately 30 percent of the scroll's text, revealing new details about Plato's life as well as his place of burial.

Most notably, the historical account of Plato being sold into slavery in his later years after running afoul of the tyrannical Dionysius is usually pegged to around 387 BCE. According to the newly deciphered Philodemus text, however, Plato's enslavement may have occurred as early as 404 BCE or shortly after the death of Socrates in 399 BCE.

"Compared to previous editions, there is now an almost radically changed text, which implies a series of new and concrete facts about various academic philosophers," Graziano Ranocchia, lead researcher on the project, said. "Through the new edition and its contextualization, scholars have arrived at unexpected interdisciplinary deductions for ancient philosophy, Greek biography and literature, and the history of the book.”

Other deciphering efforts are also still underway. For instance, last fall we reported on the use of machine learning to decipher the first letters from a previously unreadable ancient scroll found in an ancient Roman villa at Herculaneum—part of the 2023 Vesuvius Challenge. And earlier this year tech entrepreneur and challenge co-founder Nat Friedman announced via X (formerly Twitter) that they had awarded the grand prize of $700,000 for producing the first readable text.

When the Vesuvius Challenge co-founders started the challenge, they thought there was less than a 30 percent chance of success within the year since, at the time, no one had been able to read actual letters inside of a scroll. However, the crowdsourcing approach proved wildly successful. That said, it's still just 5 percent of a single scroll.

So there is a new challenge for 2024: $100,000 for the first entry that can read 90 percent of the four scrolls scanned thus far. The primary goal is to perfect the auto-segmentation process since doing so manually is both time-consuming and expensive (more than $100 per square centimeter). This will lay the foundation for one day being able to scan and read all 800 scrolls discovered so far, as well as any additional scrolls that are unearthed should the remaining levels of the villa finally be excavated.

Building a robot that could pick up delicate objects like eggs or blueberries without crushing them took lots of control algorithms that process feeds from advanced vision systems or sensors that emulate the human sense of touch. The other way was to take a plunge into the realm of soft robotics, which usually means a robot with limited strength and durability.

Now, a team of researchers at Harvard University published a study where they used a simple hydraulic gripper with no sensors and no control systems at all. All they needed was silicon oil and lots of tiny rubber balls. In the process, they’ve developed a metafluid with a programmable response to pressure.

Swimming rubber spheres

“I did my PhD in France on making a spherical shell swim. To make it swim, we were making it collapse. It moved like a [inverted] jellyfish,” says Adel Djellouli, a researcher at Bertoldi Group, Harvard University, and the lead author of the study. “I told my boss, 'hey, what if I put this sphere in a syringe and increase the pressure?' He said it was not an interesting idea and that this wouldn’t do anything,” Djellouli claims. But a few years and a couple of rejections later, Djellouli met Benjamin Gorissen, a professor of mechanical engineering at the University of Leuven, Belgium, who shared his interests. “I could do the experiments, he could do the simulations, so we thought we could propose something together,” Djellouli says. Thus, Djellouli’s rubber sphere finally got into the syringe. And results were quite unexpected.

The sphere has a radius of 10 mm, and its 2-mm-thick silicone rubber walls surround a pocket of air. It was placed in a container with 300 ml of water. When the pressure in the container started to increase, the sphere, at 120 kPa, started to buckle. Once it started to buckle, pressure remained relatively steady for a while, even though the volume occupied by the fluid continued dropping. The liquid with a sphere in it did not behave like water anymore—it had a pronounced plateau in its pressure/volume curve. “Metafluids—liquids with tunable properties that do not exist in nature—were theorized by Federico Capasso and colleagues, who wanted to achieve a liquid with negative refractive index. They started with optics back then, but looking at the behavior of water with this rubber sphere in it, we knew what we had was a metafluid,” says Djellouli.

Mixing programmable fluids

Putting a single rubber sphere in the water was just a starting point. “I always had this idea in the back of my head: Like, what would happen if I put in a lot of them?” Djellouli told Ars. So, his team started to experiment with different sizes and numbers of the spheres in the medium and using different mediums like silicon oil. “You can tune pressure at which the spheres activate by changing their radius and thickness of their walls. When you make the spheres thicker, you need more energy to make them buckle and thus the activation pressure will be higher,” explains Djellouli.

There are other parameters that can be changed to program desired properties in the metafluid. These include the volume fraction—basically how much of the total fluid’s volume is taken by the spheres—and the structure of the spheres, as the fluid behaves differently when you put spheres with different sizes and thickness in it. You can also tune this by using mixtures of spheres with different properties. “If the variation in size and thickness of the spheres is very tight, you are going to have a very flat plateau of pressure when they activate. If you have a wider distribution, the transition from all unbuckled to all buckled will be smoother,” says Djellouli. Using different mixtures of spheres also enables multiple plateaus at different pressures in one fluid. “This way you can precisely tune the pressure/volume curve,” Djellouli adds.

By tuning those curves, his team managed to build a smart hydraulic gripper that works without the need for sensors or control systems.

Self-controlled robots

The goal for the gripper was to grab and hold three objects—a water bottle, an egg, and a blueberry—without crushing them. The basic design was very simple: one static finger and a second that opened and closed the grip based on the motion of a hydraulic piston. “Let’s say I want to give this actuator control but without me doing any control, and I want it to grab many different objects that vary in size, weight, and fragility,” says Djellouli.

His team started by doing this experiment with plain water and air acting as the hydraulic fluids driving the piston. It turned out there was no single volume of hydraulic material that would allow the device to grab all of them. Too little and it wouldn’t close on small objects.

“In this scenario you need to spend some fluid volume to reach the object first,” Djellouli explained. This reach volume was the highest for the blueberry, the smallest object, and the lowest for the bottle, the largest of the three. “When the gripper gets in contact with the object, it stops moving, and adding more fluid to the system starts to increase pressure to the point your object is crushed,” Djellouli said. “But with the metafluid we could do this. We tuned it to reach and hold all the objects without crushing them,” says Djellouli. His team introduced two plateaus in the metafluid that enabled the gripper to reach and hold the blueberry but kept the pressure in the safe range while grabbing the bottle and the egg.

The same trick can be used to introduce some degree of intelligence to otherwise crude and simple robots. “We can make hydraulic actuators soft and self-controlled. The fluid itself is doing all the control for us, so we don’t have to control the robot from the outside,” he adds.

Smartening up hydraulic grippers is just one of the talents of Djellouli’s metafluid. Many more came to light when the team started to make the spheres smaller, taking their size down to micrometer scale.

Optics and smart shock absorbers

“On the face of it, you could argue we didn’t need to make the spheres small. One of the professors told me miniaturizing them was not necessary because it would take lots of time and bring little added value,” Djellouli claims.

But it turned out there was added value. “In one of the experiments we noticed that when the pressure was low, the fluid was opaque, but when you activated the shells, it turned transparent,” Djellouli explains. This effect was discovered when the team put micrometer-scale spheres made with polydimethylsiloxane (PDMS), a transparent elastomer, in PDMS oil. “In an unbuckled state there was a high volume of air in the fluid. It was opaque because air and PDMS have different refractive indexes. But when the spheres buckled, the volume of air became very low, and the buckled spheres took a shape similar to what you find in contact lenses, which made the fluid transparent,” explains Djellouli.

But miniaturizing the spheres led to even more profound discovery. “We could tune the fluid’s rheology,” Djellouli said, referring to how smoothly it flowed. The team noticed that a fluid with compressed spheres flowed faster than one with non-activated spheres, even when driven by the same pressure difference between the input and outlet.

This opens a way to building things like intelligent shock absorbers that can change their characteristics. “Impacts and amplitude of the shock can be translated into pressure, and based on that you can tune the rheology depending on the impact that you are having. I think this can be done. If companies making shock absorbers think this could be a good system, we’d like to meet them and see if we can work with them,” says Djellouli. “But when it comes to rheology, now we are just scratching the surface,” he adds.

Nature, 2024.  DOI: 10.1038/s41586-024-07163-z

Engineers have partially restored a 1970s-era computer on NASA's Voyager 1 spacecraft after five months of long-distance troubleshooting, building confidence that humanity's first interstellar probe can eventually resume normal operations.

Several dozen scientists and engineers gathered Saturday in a conference room at NASA's Jet Propulsion Laboratory, or connected virtually, to wait for a new signal from Voyager 1. The ground team sent a command up to Voyager 1 on Thursday to recode part of the memory of the spacecraft's Flight Data Subsystem (FDS), one of the probe's three computers.

“In the minutes leading up to when we were going to see a signal, you could have heard a pin drop in the room," said Linda Spilker, project scientist for NASA's two Voyager spacecraft at JPL. "It was quiet. People were looking very serious. They were looking at their computer screens. Each of the subsystem (engineers) had pages up that they were looking at, to watch as they would be populated."

Finally, a breakthrough

Launched nearly 47 years ago, Voyager 1 is flying on an outbound trajectory more than 15 billion miles (24 billion kilometers) from Earth, and it takes 22-and-a-half hours for a radio signal to cover that distance at the speed of light. This means it takes nearly two days for engineers to uplink a command to Voyager 1 and get a response.

In November, Voyager 1 suddenly stopped transmitting its usual stream of data containing information about the spacecraft's health and measurements from its scientific instruments. Instead, the spacecraft's data stream was entirely unintelligible. Because the telemetry was unreadable, experts on the ground could not easily tell what went wrong. They hypothesized the source of the problem might be in the memory bank of the FDS.

There was a breakthrough last month when engineers sent up a novel command to "poke" Voyager 1's FDS to send back a readout of its memory. This readout allowed engineers to pinpoint the location of the problem in the FDS memory. The FDS is responsible for packaging engineering and scientific data for transmission to Earth.

After a few weeks, NASA was ready to uplink a solution to get the FDS to resume packing engineering data. This data stream includes information on the status of the spacecraft—things like power levels and temperature measurements. This command went up to Voyager 1 through one of NASA's large Deep Space Network antennas Thursday.

Then, the wait for a response. Spilker, who started working on Voyager right out of college in 1977, was in the room when Voyager 1's signal reached Earth Saturday.

"When the time came to get the signal, we could clearly see all of a sudden, boom, we had data, and there were tears and smiles and high fives," she told Ars. "Everyone was very happy and very excited to see that, hey, we're back in communication again with Voyager 1. We're going to see the status of the spacecraft, the health of the spacecraft, for the first time in five months."

Throughout the five months of troubleshooting, Voyager's ground team continued to receive signals indicating the spacecraft was still alive. But until Saturday, they lacked insight into specific details about the status of Voyager 1.

“It’s pretty much just the way we left it," Spilker said. "We're still in the initial phases of analyzing all of the channels and looking at their trends. Some of the temperatures went down a little bit with this period of time that's gone on, but we're pretty much seeing everything we had hoped for. And that's always good news.”

Relocating code

Through their investigation, Voyager's ground team discovered a single chip responsible for storing a portion of the FDS memory stopped working, probably due to either a cosmic ray hit or a failure of aging hardware. This affected some of the computer's software code.

"That took out a section of memory," Spilker said. "What they have to do is relocate that code into a different portion of the memory, and then make sure that anything that uses those codes, those subroutines, know to go to the new location of memory, for access and to run it."

Only about 3 percent of the FDS memory was corrupted by the bad chip, so engineers needed to transplant that code into another part of the memory bank. But no single location is large enough to hold the section of code in its entirety, NASA said.

So the Voyager team divided the code into sections for storage in different places in the FDS. This wasn't just a copy-and-paste job. Engineers needed to modify some of the code to make sure it will all work together. "Any references to the location of that code in other parts of the FDS memory needed to be updated as well," NASA said in a statement.

Newer NASA missions have hardware and software simulators on the ground, where engineers can test new procedures to make sure they do no harm when they uplink commands to the real spacecraft. Due to its age, Voyager doesn't have any ground simulators, and much of the mission's original design documentation remains in paper form and hasn't been digitized.

"It was really eyes-only to look at the code," Spilker said. "So we had to triple check. Everybody was looking through and making sure we had all of the links coming together."

This was just the first step in restoring Voyager 1 to full functionality. "We were pretty sure it would work, but until it actually happened, we didn't know 100 percent for sure," Spilker said.

"The reason we didn’t do everything in one step is that there was a very limited amount of memory we could find quickly, so we prioritized one data mode (the engineering data mode), and relocated only the code to restore that mode," said Jeff Mellstrom, a JPL engineer who leads the Voyager 1 "tiger team" tasked with overcoming this problem.

"The next step, to relocate the remaining three actively used science data modes, is essentially the same," Mellstrom said in a written response to Ars. "The main difference is the available memory constraint is now even tighter. We have ideas where we could relocate the code, but we haven’t yet fully assessed the options or made a decision. These are the first steps we will start this week."

It could take "a few weeks" to go through the sections of code responsible for packaging Voyager 1's science data in the FDS, Spilker said.

That will be the key payoff, Spilker said. Voyager 1 and its twin spacecraft, Voyager 2, are the only operating probes flying in the interstellar medium, the diffuse gas between the stars. Their prime missions are long over. Voyager 1 flew by Jupiter and Saturn in 1979 and 1980, then got a gravitational boost toward the outer edge of the Solar System. Voyager 2 took a slower trajectory and encountered Jupiter, Saturn, Uranus, and Neptune.

For the last couple of decades, NASA has devoted Voyager's instruments to studying cosmic rays, the magnetic field, and the plasma environment in interstellar space. They're not taking pictures anymore. Both probes have traveled beyond the heliopause, where the flow of particles emanating from the Sun runs into the interstellar medium.

But any scientific data collected by Voyager 1 since November 14 has been lost. The spacecraft does not have the ability to store science data onboard. Voyager 2 has remained operational during the outage of Voyager 1.

Scientists are eager to get their hands on Voyager 1's science data again. "With the results we got on Saturday, we have new confidence that we can put together the pieces we need to now get back the science data," Spilker said.

"One thing I'm particularly excited about, there's this feature in the Voyager 1 data. We nicknamed it pressure front 2," Spilker said. "Pressure front 2 is a jump in both the density of the plasma around the spacecraft and the magnetic field. It's lasted for three-and-a-half years.

"We'd like to see, is this still there?" she continued. "It's different from what we've seen in the past, and we're trying to figure out, is it some influence coming from the Sun, or is it actually something coming from interstellar space that's creating this feature? So we'd like to see it again, get more data, and be able to study it more carefully.”

Listing image by NASA

Good morning. It's April 23, and today's photo comes from the Hubble Space Telescope. It features a lovely, barred spiral galaxy and a photobombing star on the right-hand side of the image.

The galaxy is NGC 3783, which can be found 130 million light-years away from Earth. Astronomical distances are all mind-boggling, but to try to put things into perspective, that means this galaxy is about 1,000 times the distance farther from us compared to the diameter of our own Milky Way Galaxy. So it's far, far away.

The star, HD 101274, is much closer. It is located about 1,530 light-years from Earth, which is well within our own galaxy. If you look around the edges of the bright galaxy in the middle of the image, you can see many other spherical and oddball shaped galaxies that are out there, whizzing around the cosmos doing their thing. Whatever that is.

Source: ESA/Hubble & NASA, M. C. Bentz, D. J. V. Rosario

NASA has formally approved the robotic Dragonfly mission for full development, committing to a revolutionary project to explore Saturn's largest moon with a quadcopter drone.

Agency officials announced the outcome of Dragonfly's confirmation review last week. This review is a checkpoint in the lifetime of most NASA projects and marks the moment when the agency formally commits to the final design, construction, and launch of a space mission. The outcome of each mission's confirmation review typically establishes a budgetary and schedule commitment.

“Dragonfly is a spectacular science mission with broad community interest, and we are excited to take the next steps on this mission," said Nicky Fox, associate administrator of NASA's science mission directorate. "Exploring Titan will push the boundaries of what we can do with rotorcraft outside of Earth.”

In the case of Dragonfly, NASA confirmed the mission with a total lifecycle cost of $3.35 billion and a launch date of July 2028. That is roughly twice the mission's original proposed cost and a delay of more than two years from when the mission was originally selected in 2019, according to NASA.

Busting the cost cap

Rising costs are not necessarily a surprise on a mission as innovative as Dragonfly. After reaching Titan, the eight-bladed rotorcraft lander will soar from place to place on Saturn's hazy moon, exploring environments rich in organic molecules, the building blocks of life.

Dragonfly will be the first mobile robot explorer to land on any other planetary body besides the Moon and Mars, and only the second flying drone to explore another planet. NASA's Ingenuity helicopter on Mars was the first. Dragonfly will be more than 200 times as massive as Ingenuity and will operate six times farther from Earth.

Despite its distant position in the cold outer Solar System, Titan appears to be reminiscent of the ancient Earth. A shroud of orange haze envelops Saturn's largest moon, and Titan's surface is covered with sand dunes and methane lakes.

Titan's frigid temperatures—hovering near minus 290° Fahrenheit (minus 179° Celsius)—mean water ice behaves like bedrock. NASA's Cassini spacecraft, which flew past Titan numerous times before its mission ended in 2017, discovered weather systems on the hazy moon. Observations from Cassini found evidence for hydrocarbon rains and winds that appear to generate waves in Titan's methane lakes.

Clearly, Titan is an exotic world. Most of what scientists know about Titan comes from measurements collected by Cassini and the European Space Agency's Huygens probe, which Cassini released to land on Titan in 2005. Huygens returned the first pictures from Titan's surface, but it only transmitted data for 72 minutes.

Dragonfly will explore Titan for around three years, flying tens of kilometers about once per month to measure the prebiotic chemistry of Titan's surface, study its soupy atmosphere, and search for biosignatures that could be indications of life. The mission will visit more than 30 locations within Titan's equatorial region, according to a presentation by Elizabeth Turtle, Dragonfly's principal investigator at the Johns Hopkins University Applied Physics Laboratory.

"The Dragonfly mission is an incredible opportunity to explore an ocean world in a way that we have never done before,” Turtle said in a statement. “The team is dedicated and enthusiastic about accomplishing this unprecedented investigation of the complex carbon chemistry that exists on the surface of Titan and the innovative technology bringing this first-of-its-kind space mission to life."

However, this high level of ambition comes at a high cost. NASA selected Dragonfly to proceed into initial development in 2019. Turtle's science team proposed Dragonfly to NASA through the agency's New Frontiers program, which has developed a series of medium-class Solar System exploration missions. The New Frontiers program has an impressive pedigree, beginning with the New Horizons mission that flew by Pluto in 2015, the Juno mission to Jupiter, and the OSIRIS-REx asteroid sample return mission.

Dragonfly's lifecycle cost of $3.35 billion will make it significantly more expensive than any of those missions.

When NASA chose Dragonfly in 2019, the mission had a cost cap of $850 million ($1 billion when adjusted for inflation) to get it to the launch pad. The budget limit didn't include the launch or costs to operate the Dragonfly spacecraft after launch. The costs originally under the budget cap have increased the $1 billion post-inflation figure to $2.1 billion, according to NASA.

Since 2019, NASA had to replan the Dragonfly mission multiple times due to funding constraints that limited how much the agency could spend on the project each fiscal year. Managers navigated the challenges imposed by the pandemic and supply chain issues. There was also an "in-depth design iteration," the agency said in a statement.

During this time, NASA directed managers in charge of Dragonfly to delay its launch from 2026 to 2027, which required the mission to change from a medium-lift to a heavy-lift launcher. As a result of this, NASA upped the funding for Dragonfly to pay for a bigger rocket. Dragonfly's updated launch window in July 2028 will still require a high-energy launch, likely on a SpaceX Falcon Heavy or a United Launch Alliance Vulcan rocket. NASA will likely select a launch provider for Dragonfly later this year.

Collectively, these pressures caused Dragonfly's lifecycle cost to grow to $3.35 billion, more in line with a flagship-class interplanetary mission than a cost-capped project. The two most recent New Frontiers missions came in between $1 billion and $1.5 billion, while Europa Clipper, NASA's next flagship planetary science probe, will cost around $5 billion.

NASA's commitment to Dragonfly also comes as the agency faces budget cuts. These reductions have hit the agency's planetary science division particularly hard. NASA is revamping plans for its big planetary flagship mission, Mars Sample Return, to try to rein in growing costs. The agency has postponed a call for scientists to propose concepts for the next New Frontiers mission that will follow Dragonfly.

Despite the higher costs, Dragonfly escaped cancellation. A major reason for this appears to be that NASA's budgetary limitations, and not any mismanagement from within the Dragonfly project, were responsible for a large share of the cost growth.

Assuming a launch in July 2028, Dragonfly will arrive at Titan in December 2034. Cocooned inside a heat shield and aeroshell, Dragonfly will enter Titan's atmosphere and deploy a parachute to slowly descend to the surface over the course of nearly two hours. Then, the quadcopter will settle onto the ground with its fixed landing skids.

At the surface, Titan's atmosphere is four times thicker than Earth's. This makes the process of getting to the ground a lot longer than a lander entering the atmosphere of Earth or Mars, but the higher air density should provide excellent flying conditions.

In June 1924, a British mountaineer named George Leigh Mallory and a young engineering student named Andrew "Sandy" Irvine set off for the summit of Mount Everest and disappeared—just two casualties of a peak that has claimed over 300 lives to date. Mallory was an alumnus of Magdalene College at the University of Cambridge, which maintains a collection of his personal correspondence, much of it between Mallory and his wife, Ruth. The college has now digitized the entire collection for public access. The letters can be accessed and downloaded here.

“It has been a real pleasure to work with these letters," said Magdalene College archivist Katy Green. "Whether it’s George’s wife Ruth writing about how she was posting him plum cakes and a grapefruit to the trenches (he said the grapefruit wasn’t ripe enough), or whether it’s his poignant last letter where he says the chances of scaling Everest are '50 to 1 against us,' they offer a fascinating insight into the life of this famous Magdalene alumnus.”

As previously reported, Mallory is the man credited with uttering the famous line "because it's there" in response to a question about why he would risk his life repeatedly to summit Everest. An avid mountaineer, Mallory had already been to the mountain twice before the 1924 expedition: once in 1921 as part of a reconnaissance expedition to produce the first accurate maps of the region and again in 1922—his first serious attempt to summit, although he was forced to turn back on all three attempts. A sudden avalanche killed seven Sherpas on his third try, sparking accusations of poor judgement on Mallory's part.

Undeterred, Mallory was back in 1924 for the fated Everest expedition that would claim his life at age 37. He aborted his first summit attempt, but on June 4, he and Irvine left Advanced Base Camp (21,330 feet/6,500 meters). They reached Camp 5 on June 6, and Camp 6 the following day, before heading out for the summit on June 8. Team member Noel Odell reported seeing the two men climbing either the First or Second Step around 1 pm before they were "enveloped in a cloud once more."

Nobody ever saw Mallory and Irvine again, although their spent oxygen tanks were found just below the First Step. Climbers also found Irvine's ice axe in 1933. Mallory's body wasn't found until 1999, when an expedition partially sponsored by Nova and the BBC found the remains on the mountain's north face, at 26,760 feet (8,157 meters)—just below where Irvine's axe had been found. The name tags on the clothing read "G. Leigh Mallory." Personal artifacts confirmed the identity: an altimeter, a pocket knife, snow goggles, a letter, and a bill for climbing equipment from a London supplier. Irvine's body has yet to be found, despite the best efforts of a 2019 National Geographic expedition, detailed in the riveting 2020 documentary Lost on Everest.

The collection makes for some fascinating reading; Mallory led an adventurous life. Among the highlights of the Magdalene College collection is the final letter Mallory wrote to Ruth before attempting his fateful last summit attempt:

“Darling I wish you the best I can—that your anxiety will be at an end before you get this—with the best news. Which will also be the quickest. It is 50 to 1 against us but we’ll have a whack yet & do ourselves proud. Great love to you. Ever your loving, George.”

Three of the letters were found in Mallory's jacket pocket 75 years after his disappearance when his body was discovered, exceptionally well-preserved. Other letters detailed his experiences at the Battle of the Somme during World War II; his first reconnaissance expedition to Everest; and the aforementioned second Everest expedition in which seven Sherpas were lost. On a lighter note are letters describing his adventures during a 1923 trip to the Prohibition Era US. (He would ask for milk at speakeasies and get whiskey served to him through a secret hatch.) There are also letters from Ruth—including her only surviving letter to Mallory during his Everest explorations—and from Mallory's sister, Mary Brooke.

Intermittent fasting, aka time-restricted eating, can help people lose weight—but the reason why may not be complicated hypotheses about changes from fasting metabolism or diurnal circadian rhythms. It may just be because restricting eating time means people eat fewer calories overall.

In a randomized-controlled trial, people who followed a time-restricted diet lost about the same amount of weight as people who ate the same diet without the time restriction, according to a study published Friday in Annals of Internal Medicine.

The finding offers a possible answer to a long-standing question for time-restricted eating (TRE) research, which has been consumed by small feeding studies of 15 people or fewer, with mixed results and imperfect designs.

The new study—led by Nisa Marisa Maruthur, an internal medicine expert at Johns Hopkins—has its own limitations and, like any one study, isn't the last word on the matter. But "it takes us one step closer to identifying the underlying mechanisms of TRE," nutrition experts Krista Varady and Vanessa Oddo of the University of Illinois wrote in an editorial accompanying the study. "Using a controlled feeding design, Maruthur and colleagues show that TRE is effective for weight loss, simply because it helps people eat less."

The study involved 41 people, 21 who followed a time-restricted diet for 12 weeks and 20 who ate a usual eating pattern (UEP). Most of the participants were Black women (93 percent) with obesity and either pre-diabetes or diet-controlled diabetes, limiting the generalizability of the findings. But the study carefully controlled what and when the participants ate; each participant got controlled meals (breakfast, lunch, dinner, and snack) with identical macro- and micro-nutrients. Each participant was assigned a calorie level for their meals based on an established, standardized equation that estimates baseline caloric need. They were told to maintain their current exercise level, which was monitored with a wrist-worn accelerometer.

No magic necessary

In the time-restricted group, people only ate in a 10-hour window between 8 am and 6 pm, with 80 percent of their total daily calories consumed before 1 pm. In the usual eating group, people ate between 8 am and midnight, with 55 percent of their calories eaten after 5 pm for dinner and a night-time snack. In each eating group, participants were given specific windows of a couple of hours in which they should eat each pre-made meal. The participants ate three meals each week at a research site, where dieticians addressed adherence issues, and their eating was carefully monitored with the use of food diaries and urine tests. Approximately 96 percent of people in both groups followed the schedules to within 30 minutes. Diet adherence—eating all their assigned food and not eating outside food—was also high, with 93 percent in the time-restricted group and 95 percent in the usual eating group.

At the end of the 12 weeks, both groups lost about the same amount of weight, an average of around 2.4 kg (5.3 pounds), with no statistically significant difference between the two groups. The researchers also found no differences between the two groups in their glucose homeostasis, waist circumference, blood pressure, or lipid levels.

"Our results indicate that when food intake is matched across groups and calories are held constant, TRE, as operationalized in our study, does not enhance weight loss," Maruthur and her colleagues concluded. The authors are upfront about the limitations of the study, though, noting that the results could have been different in different groups of people and potentially in shorter time-restricted windows, such as eight hours instead of 10. They called for more research to explore those questions.

Outside experts applauded the study while also adding that it's not surprising. "The headline finding that TRE does not magically lead to more weight loss sounds sensational but is also obvious," Adam Collins, a nutrition expert at the University of Surrey, said.

Naveed Sattar, a professor of cardiometabolic medicine at the University of Glasgow, called the study "well done." It "tells us what we expected—that there is nothing magical about time-restricted eating on weight change other than effects to reduce caloric intake," he said. "If time-restricted eating helps some people eat less calories than they would otherwise, great."

The experts Varady and Oddo, meanwhile, see it as a boon for anyone trying to lose weight. "Many patients stop following standard-care diets (such as daily calorie restriction) because they become frustrated with having to monitor food intake vigilantly each day," they wrote in their commentary. "Thus, TRE can bypass this requirement simply by allowing participants to 'watch the clock' instead of monitoring calories while still producing weight loss." It's a "simplified" and "accessible" dietary strategy that anyone can follow, including lower-resource populations, the researchers wrote.

The first-ever model of Star Trek's USS Enterprise NCC-1701 has been returned to the Roddenberry family, according to an ABC News report.

The three-foot model was used to shoot the pilot and credits scene for Star Trek's original series in the 1960s and was used occasionally for shots throughout the series. (Typically, a larger, 11-foot model was used for shots after the pilot.) The model also sat on series creator Gene Roddenberry's desk for several years.

It went missing in the late 1970s; historians and collectors believe it belonged to Roddenberry himself, that he lent it to a production house working on Star Trek: The Motion Picture, and that it was never returned. Its whereabouts were unknown until last fall, when a listing for a mysterious model of the Enterprise appeared on eBay.

The eBay account that posted the item specialized in selling artifacts found in storage lockers that end up without an owner, either because of failure to pay or death.

The model was turned over by the eBay seller to Texas-based Heritage Auctions. News spread that it had been discovered, and Gene Roddenberry's son, Eugene "Rod" Roddenberry, made public statements that he would like to see it returned to his family.

After that, there were months of silence, and its fate was unknown—until now. Heritage Auctions announced that it had given the model to Rod Roddenberry. Details of the exchange have not been shared, but Roddenberry said he did compensate Heritage in some way.

Heritage reached out directly to Roddenberry upon acquiring the object and reportedly decided to return it because it was "the right thing to do." Roddenberry said that he "felt it important to reward that and show appreciation for that" but didn't disclose a sum.

Roddenberry also revealed what he has planned for the model:

This is not going home to adorn my shelves. This is going to get restored and we’re working on ways to get it out so the public can see it, and my hope is that it will land in a museum somewhere.

He runs a group called the Roddenberry Foundation that has scanned and digitized many relics from Star Trek's ideation and production over the years, so it's likely the Foundation will get a crack at the model, too.

Listing image by eBay

Ever since the Voyager mission sent home images of Jupiter's moon Io spewing material into space, we've gradually built up a clearer picture of Io's volcanic activity. It slowly became clear that Io, which is a bit smaller than Mercury, is the most volcanically active body in the Solar System, with all that activity driven by the gravitational strain caused by Jupiter and its three other giant moons. There is so much volcanism that its surface has been completely remodeled, with no signs of impact craters.

A few more details about its violence came to light this week, with new images being released of the moon's features, including an island in a lake of lava, taken by the Juno orbiter. At the same time, imaging done using an Earth-based telescope has provided some indications that this volcanism has been reshaping Io from almost the moment it formed.

Fiery, glassy lakes

The Juno orbiter's mission is primarily focused on studying Jupiter, including the dynamics of its storms and its internal composition. But many of its orbital passes have taken it right past Io, and this week, the Jet Propulsion Laboratory released some of the best images from these flybys. They include a shot of Loki Patera, a lake of lava that has an island within it. Also featured: the impossibly sheer slopes of Io's Steeple Mountain.

Looking more closely at the lake, the Juno team found that some of the areas within it were incredibly smooth, raising the possibility that obsidian glass had formed on the surface where it had cooled enough to solidify. Given the level of volcanism on Io, this may be more widespread than the Loki Patera.

Volcanic ash would also create a relatively smooth surface, and is likely to be even more common, but it would have significantly different reflective properties.

How long has this been going on?

But we don't have to send hardware to Jupiter to learn something about Io. A US-based team got time on the Atacama Large Millimeter Array (ALMA) and used it to record emissions from atoms in Io's sparse atmosphere. By combining the imaging power of lots of smaller telescopes scattered across a plateau, ALMA is able to spot regional differences in the presence of specific elements in Io's atmosphere, as well as identify different isotopes of those elements.

What can isotopes tell us? Any atoms that reach Io's upper atmosphere are at risk of being lost to space. And, because of their relative atomic weights, lighter isotopes have a higher probability of being lost. So, it's possible to compare the present ratio of elements in the atmosphere with the expected ratio, and we can make inferences about the history of loss of lighter isotopes. And, since the material is put into the atmosphere by volcanoes in the first place, that tells us something about the history of volcanism.

The research team focused on two particular elements: sulfur and chlorine. Sulfur has two common non-radioactive isotopes, ³²S and ³⁴S, and chlorine, its neighbor on the periodic table, has ³⁵Cl and ³⁷Cl. There are differences in the ratio of these isotopes throughout the bodies of the Solar System, but those differences are generally small. And, because we think we know what sort of material contributed to the formation of Io, we can focus on the ratios found in bodies that have a similar origin.

Chlorine enters the atmosphere from volcanoes primarily in the form of sodium and potassium salts. These have a very short half-life before they're split up by exposure to light and radiation. The ALMA data indicated both these chemicals were present in localized regions, likely corresponding to active volcanic plumes. The data from the chlorine isotopes were a bit noisy, so were largely used as a sanity check for the ones obtained from sulfur isotopes.

Recycling sulfur

Sulfur is largely in the form of oxides (SO and SO₂), which are much longer lived. As a result, it's much more widely distributed in the atmosphere.

There were isotope differences between the leading and trailing edge of the moon, so the researchers took the average of the two. That average showed a very large excess of the heavier sulfur isotope compared to the average seen in the Solar System. There's only one body that is anywhere close (the comet Hale-Bopp), but that's likely because the uncertainties on the comet's data are so large.

There's really no way to produce that sort of excess through a single trip into the atmosphere. Instead, the authors think Io has been recycling the sulfur dioxide through the atmosphere, back to the surface, and then sending it through volcanoes into the atmosphere repeatedly. In fact, taking the current rate of mass loss, they calculate that Io's volcanism dates back to the formation of the moon, meaning it has been geologically active for its entire history.

Similar calculations suggest that this rate of loss means that Io has exhausted about 95 percent of the sulfur that is available to its volcanic system. The researchers suggest that there's still going to be plenty of sulfur on the moon, most likely mixed with iron at its core. But the large depletion of the lighter isotope suggests that anything in the core isn't participating in the moon's volcanic activity.

The intriguing thing about this—or at least one of them—is that it implies that Io has some system that's cycling the sulfur dioxide that erupts to the surface back into the interior of the moon where it can take part in volcanism again. There's no indication of any plate tectonics on the moon, so we don't have a clear analog for what can be driving the process on Io.

Science, 2024. DOI: 10.1126/science.adj0625  (About DOIs).

An AI test pilot has successfully flown a jet fighter in dogfights against human opponents. It's the latest development for DARPA's Air Combat Evaluation program, which is trying to develop aerospace AI agents that can be trusted to perform safely.

Human test pilots have a bit of a reputation thanks to popular culture—from The Right Stuff to Top Gun: Maverick, the profession has been portrayed as a place for loose cannons with a desire to go fast and break the rules. The reality is pretty far from that these days, especially where DARPA is concerned.

The agency instead wants a machine-learning agent that can safely fly a real aircraft autonomously, with no violations of training rules. After all, neural networks have their own reputation—at this point well-earned—for finding ways to exploit situations that hadn't occurred to humans. And the consequences when controlling a real jet fighter can be a lot more severe than just testing in silico.

In this case, the jet fighter is called the X-62A Variable Stability In-Flight Simulator Test Aircraft, or VISTA. It began life as an F-16D (Block 30) two-seater, which spent most of its 32-year career working at the US Air Force Test Pilot School at Edwards AFB.

Over the years, the plane, previously designated the NF-16D, has been modified to simulate the flight characteristics of other aircraft while in flight. "It has given almost a thousand students and staff members the opportunity to practice testing aircraft with dangerously poor flying qualities and to execute risk-reduction flight test programs for advanced technologies," said William Gray, chief test pilot of VISTA and the USAF Test Pilot School.

That made it a natural candidate for DARPA's ACE program, and in 2021, the process of modifying the aircraft began once again as it became the X-62A.

The USAF and DARPA started conducting X-62A test flights under AI control in December 2022, logging 17 hours by the time we first learned of the program in early 2023. Although DARPA's AI agent flew the X-62A, there was always a pair of human pilots onboard to monitor the test flight and, if necessary, take control. But in those early tests, the X-62A flew against simulated adversaries.

By September 2023, the program had completed 21 test flights, including the first-ever AI versus human aerial engagement within visual range, flying against a human-piloted F-16. During that time, DARPA says the team made over 100,000 lines of flight-critical software changes, which it called "an unprecedented rate of development."

That's certainly an achievement, but just focusing on the dogfight is a mistake, according to Gray. "That misses the point. Dogfighting was the problem to solve so we could start testing autonomous artificial intelligence systems in the air, but every lesson we're learning applies to every task we can give to an autonomous system," he said.

Welcome to Edition 6.40 of the Rocket Report! There was a lot of exciting news this week. For the first time, SpaceX launched a reusable Falcon 9 booster for a 20th flight. A few miles away at Cape Canaveral, Boeing and United Launch Alliance completed one of the final steps before the first crew launch of the Starliner spacecraft. But I think one of the most interesting things that happened was NASA's decision to ask the space industry for more innovative ideas on how to do Mars Sample Return. I have no doubt that space companies will come up with some fascinating concepts, and I can't wait to hear about them.

As always, we welcome reader submissions, and if you don't want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets, as well as a quick look ahead at the next three launches on the calendar.

Going vertical Down Under. Gilmour Space has raised its privately developed Eris rocket vertical on a launch pad in North Queensland for the first time, the Australian Broadcasting Corporation reports. This milestone marks the start of the next phase of launch preparations for Eris, a three-stage rocket powered by hybrid engines. If successful, Eris would become the first Australian-built rocket to reach orbit. Gilmour says the maiden flight of Eris is scheduled for no earlier than May 4, pending launch permit approvals. This presumably refers to a commercial launch license from the Australian government.

A milestone for Australia... Rockets from the United States and the United Kingdom have launched satellites from Australian soil before, but Gilmour aims to become the first to do this with an entirely homemade rocket. The Eris rocket is capable of hauling about 670 pounds (305 kilograms) into a Sun-synchronous polar orbit. This puts Eris in the same class as other commercial small satellite launchers, such as Rocket Lab's Electron. While the commercial outlook for the Eris rocket might seem somewhat dubious, it could make history in Australia and provide that nation with its first indigenous orbital launch capability. (submitted by Onychomys)

Astrobotic seeks military business. Astrobotic is making a strategic move into the defense sector with its Xogdor reusable rocket, designed to test payloads at the edge of space, Space News reports. Perhaps most famous for its commercially developed lunar landers, Astrobotic also builds and tests small reusable rockets with vertical takeoff and vertical landing capability. These rockets were developed by Masten Space Systems, which filed for bankruptcy in 2022. Astrobotic acquired Masten a couple of months later. The next rocket developed by Astrobotic and Masten, named Xogdor, is scheduled to debut in 2025. "We think the opportunities to leverage a platform like this are extensive, and they haven’t fully been explored," said Sean Bedford, Astrobotic's director of business development for propulsion systems.

New opportunities ... Masten, and now Astrobotic, has historically flown small reusable rockets at low altitudes in the atmosphere to test propulsion technology and navigation sensors for precision landings on Earth or other planets. The liquid-fueled Xogdor will be a different animal, standing 27 feet tall and 3 feet in diameter. An upgraded version of Xodgor will have the ability to fly to altitudes higher than 62 miles (100 kilometers), according to Astrobotic. The Xogdor is funded by a NASA contract, but Bedford said Astrobotic is looking for ways the rocket can support the US military, the Missile Defense Agency, and other defense organizations for hypersonic research testing and point-to-point transportation. (submitted by Ken the Bin)

Orbex gets another tranche of funding. UK-based small launch developer Orbex got another boost from Scotland’s national bank and other investors as it gears up for its first orbital launch, though that mission still does not have a set date, TechCrunch reports. Orbex said it received £16.7 million ($20.8 million) from six financial backers in an update to its Series C funding round, which closed in October 2022 at £40.4 million ($50 million). Founded in 2015, Orbex is a privately held company, so we don't have any insight into its financial situation, but this latest funding round should be enough to keep Orbex going while it prepares for the inaugural test flight of its Prime rocket, a two-stage, 62-foot-tall (19-meter) rocket designed to loft small satellites into low-Earth orbit.

Testing and launch now in sight? ... Orbex's Prime rocket has faced chronic delays, and it's been a while since the company revealed any real schedule for the first test flight from Scotland. In mid-2022, Orbex aimed to launch Prime in late 2022 or early 2023. When Orbex announced its fresh funding Thursday, the company stated that "testing and launch (are) now in its sights." The new funding will help Orbex ramp up development of Prime and "ensure full readiness and scalability for its launch period." Whenever that is. (submitted by EllPeaTea)

20-for-20 for SpaceX's fleet leader. For the first time, SpaceX launched one of its reusable Falcon 9 boosters on its 20th mission with a flight to deliver 23 more Starlink Internet satellites to orbit, Ars reports. The successful launch and landing April 12 broke a three-way tie in SpaceX's fleet for the most-flown Falcon 9 rocket. Another launch later this month will also use a Falcon 9 booster making its 20th flight. Pretty much every day, SpaceX is either launching a rocket or rolling one out of the hangar to the launch pad. At this pace, SpaceX is redefining what is routine in the space industry, but the rapid-fire launch rate also means the company is continually breaking records, mostly its own.

Six launches in eight days ... This was also the sixth launch of a Falcon 9 rocket in a period of eight days, more flights than SpaceX's main US rival, United Launch Alliance, has launched in 17 months. The booster used on April 12, tail number B1062, has now launched more than 550 spacecraft, mostly Starlinks, plus eight commercial astronauts on two crew missions. When SpaceX debuted the latest version of its Falcon 9 rocket, the Falcon 9 Block 5, officials said the reusable first stage could fly 10 times with minimal refurbishment and perhaps additional flights with a more extensive overhaul. Now, SpaceX is certifying Falcon 9 boosters for 40 flights.

Russia's space chief is dreaming big. Yuri Borisov, head of Roscosmos, recently spoke at a Russian space museum about the country's future launch plans. Among the topics was Russia's next-generation Amur-CNG rocket, a reusable vehicle conceived as a competitor to SpaceX's Falcon 9. Borisov said the Falcon 9 could be reused about 10 times, and then claimed the Amur-CNG would be capable of much more, perhaps up to 100 flights per booster, Ars reports. The problem is the Amur-CNG is nothing more than a paper rocket at this stage. When Russian officials first discussed the Amur rocket in 2020, its first flight was scheduled for 2026. Now, that has slipped to 2028 or 2029. This is probably still an optimistic timeline, and if Amur ever flies, it will surely take even longer to recover and reuse the booster, not to mention getting to 100 flights.

Russian bluster ... This clearly was a message intended to placate an audience that must be wondering why SpaceX has launched more than three dozen rockets so far in 2024, whereas Russia has mustered just half a dozen. However, Borisov's claims fall well short of reality. Russia's once-vaunted launch industry has been much in decline due to a combination of factors, including an aging fleet of rockets, a reduction in government investment, and the country's war in Ukraine driving away Western customers. So officials turn to bluster, and this is what we're seeing here.

Everything is coming together for Starliner. Ground teams on Florida's Space Coast hoisted Boeing's Starliner spacecraft atop its United Launch Alliance Atlas V rocket this week, putting all the pieces in place for liftoff May 6 with two veteran NASA astronauts on a test flight to the International Space Station, Ars reports. This will be the first time astronauts fly on Boeing's Starliner crew capsule, following two test flights without crew members in 2019 and 2022. The Starliner Crew Flight Test (CFT) will wrap up a decade and a half of development and, if all goes well, will pave the way for operational Starliner missions to ferry crews to and from the space station.

Safety scrutiny ... In parallel with final preparations of the rocket and spacecraft, NASA and Boeing managers are participating in several reviews this month to formally clear Starliner for its first flight with astronauts. Members of NASA's Aerospace Safety Advisory Panel (ASAP) are sitting in on these reviews. Congress set up the independent panel in 1968, shortly after the deadly Apollo 1 fire, to advise NASA on safety matters. For years, ASAP members have tracked the technical problems that plagued the Starliner program, including software woes, valve corrosion, and most recently, flammable material inside the spacecraft and parachutes that didn't measure up to design specifications. “Now that the launch date is nearly here ... we have stepped up our fact finding in line with NASA’s prelaunch activity," said Susan Helms, a retired Air Force general, former astronaut, and current chair of the safety panel.

Looking back at SpaceX's first sooty rocket. Ten years ago this week, when a Falcon 9 rocket took off from Florida, something strange happened. Dramatically, as the rocket lifted off, a geyser of dirty water splashed upward alongside the vehicle, coating the rocket in grime. Eric Berger's reporting on the story of why this occurred is fascinating, particularly for reporters like me who covered the launch when it happened. Essentially, SpaceX creatively solved a problem with a leaky liquid oxygen connection by trickling water from the launch pad's fire suppression system over the oxidizer pipe. The fluid inside was flowing at cryogenic temperatures, so the water quickly froze to seal the leak. The water continued trickling over the liquid oxygen pipe through the countdown, so by the time the Falcon 9 took off, tens of thousands of gallons of water had flowed into the launch pad's flame trench. When the rocket fired its engines, dirty water and steam erupted up the side of the booster like a Bellagio fountain.

No harm, no foul … This didn't cause any problem for the rocket, but Berger's story jogged my memory from covering this launch. This story is a wonderful illustration of how quick-thinking aerospace engineers can solve problems on the fly. In this instance, thanks to this problem-solving, the small liquid oxygen leak on the launch pad didn't delay the mission to resupply the International Space Station. In many ways, this was an entirely different era for SpaceX, which was still basically a startup in 2014. This was just the ninth flight of a Falcon 9 rocket. Now, SpaceX has launched more than 330 Falcon 9 and Falcon Heavy rockets and dominates the global launch industry.

Final hotfire for Ariane 6's upper stage. ArianeGroup, builder of Europe's Ariane rocket family, conducted the final hotfire test of the new Ariane 6 rocket's upper stage in Germany. This hotfire test of the upper stage's Vinci engine was delayed from late last year, and its purpose was to gather data for future Ariane 6 missions beyond the rocket's inaugural flight planned for the middle of this year. While previous test-firings focused on demonstrating the upper stage's ability to operate under normal conditions with its cryogenic Vinci engine, this hotfire test focused on operating the upper stage during "off-nominal" conditions.

APU … A major objective of this recent upper stage hotfire test involved the Ariane 6's Auxiliary Propulsion Unit (APU). The APU is a nifty little device on the upper stage responsible for pressurizing the liquid hydrogen and liquid oxygen propellant tanks, settling propellants before each ignition of the restartable Vinci engine and generating small amounts of additional thrust on demand. This thrust can allow the Ariane 6 rocket to more precisely inject satellites into orbit, deploy clusters of payloads into slightly different orbits, and deorbit the stage at the end of its mission. This final hotfire test included three long APU boosts for a total duration of 66 minutes. (submitted by Ken the Bin and EllPeaTea)

SpaceX could play a role in Mars Sample Return. NASA's $11 billion plan to robotically bring rock samples from Mars back to Earth is too expensive and will take too long, so officials are tasking government and private sector engineers to come up with a better plan, Ars reports. SpaceX's giant Starship, designed with Mars missions in mind, could be part of the solution for NASA to bring back samples from the red planet cheaper and sooner than the 2040 schedule the agency laid out this week, according to Scientific American. NASA is encouraging companies to submit ideas using capabilities that are part of the Artemis lunar program. Starship is under contract to be the human-rated lander for the first two Artemis crew missions to the Moon's surface.

Somehow the solution … “The only conclusion you can really draw from that is they’re hoping Starship somehow is the solution here," said Casey Dreier, senior space policy adviser for the Planetary Society, in an article published by Scientific American. That could provide MSR (Mars Sample Return) with a whopper of a solution. NASA is already funding Starship, the largest rocket in history, to the tune of billions of dollars to ferry astronauts to the lunar surface—but Starship also has the potential to launch immense payloads off other worlds and back to Earth. “Starship has the potential to return serious tonnage from Mars within [about] 5 years,” noted SpaceX CEO Elon Musk on X, formerly Twitter, on April 15 in response to NASA’s MSR solicitation.

ULA has received two more BE-4 engines. Blue Origin has delivered both BE-4 main engines United Launch Alliance needs for the second flight of its Vulcan rocket later this year. The first engine was delivered in February, and ULA's CEO, Tory Bruno, posted an image on X this week showing the second BE-4 engine being installed on the Vulcan first stage at the company's factory in Alabama. Bruno previously said the first two flightworthy BE-4 engines performed flawlessly on the first Vulcan mission in January but that the supply chain for BE-4s remained in the critical path for ramping up Vulcan's flight rate to a goal of two launches per month by the end of next year.

Fall launch … ULA plans to launch the second test flight of Vulcan this fall, a few months later than hoped. The main driver to this schedule appears to be the readiness of Sierra Space's Dream Chaser spaceplane, which is undergoing environmental testing in Ohio before its delivery to Cape Canaveral for launch preparations. Dream Chaser is designed to ferry cargo and experiments to and from the International Space Station. If Dream Chaser isn't ready this year, ULA will face a choice about what to do with the second Vulcan launch. The Space Force is eager for ULA to launch the second Vulcan flight as soon as possible to get the rocket certified for national security missions.

Next three launches

April 20: Long March 2D | Unknown Payload | Xichang Satellite Launch Center, China | 23:45 UTC

April 22: Falcon 9 | Starlink 6-53 | Cape Canaveral Space Force Station, Florida | 22:40 UTC

April 23: Electron | NeonSat-1 and ACS3 | Mahia Peninsula, New Zealand | 21:30 UTC

Blue whales have been considered the largest creatures to ever live on Earth. With a maximum length of nearly 30 meters and weighing nearly 200 tons, they are the all-time undisputed heavyweight champions of the animal kingdom.

Now, digging on a beach in Somerset, UK, a team of British paleontologists found the remains of an ichthyosaur, a marine reptile that could give the whales some competition. “It is quite remarkable to think that gigantic, blue-whale-sized ichthyosaurs were swimming in the oceans around what was the UK during the Triassic Period,” said Dr Dean Lomax, a paleontologist at the University of Manchester who led the study.

Giant jawbones

Ichthyosaurs were found in the seas through much of the Mesozoic era, appearing as early as 250 million years ago. They had four limbs that looked like paddles, vertical tail fins that extended downward in most species, and generally looked like large, reptilian dolphins with elongated narrow jaws lined up with teeth. And some of them were really huge. The largest ichthyosaur skeleton so far was found in British Columbia, Canada, measured 21 meters, and belonged to a particularly massive ichthyosaur called Shonisaurus sikanniensis. But it seems they could get even larger than that.

What Lomax’s team found in Somerset was a surangular, a long, curved bone that all reptiles have at the top of the lower jaw, behind the teeth. The bone measured 2.3 meters—compared to the surangular found in the Shonisaurus sikanniensis skeleton, it was 25 percent larger. Using simple scaling and assuming the same body proportions, Lomax’s team estimated the size of this newly found ichthyosaur at somewhere between 22 and 26 meters, which would make it the largest marine reptile ever. But there was one more thing.

Examining the surangular, the team did not find signs of the external fundamental system (EFS) which is a band of tissue present in the outermost cortex of the bone. Its formation marks a slowdown in bone growth, indicating skeletal maturity. In other words, the giant ichthyosaur was most likely young and still growing when it died.

Correcting the past

In 1846, five large bones were found at the Aust Cliff near Bristol in southwestern England. Dug out from the upper Triassic rock formation, they were dubbed “dinosaurian limb bone shafts” and were exhibited in the Bristol Museum, where one of them was destroyed by bombing during World War II.

But in 2005, Peter M. Galton, a British paleontologist then working at the University of Bridgeport, noticed something strange in one of the remaining Aust Cliff bones. He described it as an “unusual foramen” and suggested it was a nutrient passage. Later studies generally kept attributing those bones to dinosaurs but pointed out things like an unusual microstructure that was difficult to explain.

According to Lomax, all this confusion was because the Aust Cliff bones did not belong to dinosaurs and were not parts of limbs. He pointed out that the nutrient foramen morphology, shape, and microstructure matched with the ichthyosaur’s bone found in Somerset. The difference was that the EFS—the mark of mature bones—was present on the Aust Cliff bones. If Lomax is correct and they really were parts of ichthyosaurs’ surangular, they belonged to a grown individual.

And using the same scaling technique applied to the Somerset surangular, Lomax estimated this grown individual to be over 30 meters long—slightly larger than the biggest confirmed blue whale.

Looming extinction

“Late Triassic ichthyosaurs likely reached the known biological limits of vertebrates in terms of size. So much about these giants is still shrouded by mystery, but one fossil at a time, we will be able to unravel their secrets,” said Marcello Perillo, a member of the Lomax team responsible for examining the internal structure of the bones.

This mystery beast didn’t last long, though. The surangular bone found in Somerset was buried just beneath a layer full of seismite and tsunamite rocks that indicate the onset of the end-Triassic mass extinction event, one of the five mass extinctions in Earth’s history. The Ichthyotian severnensis, as Lomax and his team named the species, probably managed to reach an unbelievable size but was wiped out soon after.

The end-Triassic mass extinction was not the end of all ichthyosaurs, though. They survived but never reached similar sizes again. They faced competition from plesiosaurs and sharks that were more agile and swam much faster, and they likely competed for the same habitats and food sources. The last known ichthyosaurs went extinct roughly 90 million years ago.

PLOS ONE, 2024.  DOI: 10.1371/journal.pone.0300289

Ground teams on Florida's Space Coast hoisted Boeing's Starliner spacecraft atop its United Launch Alliance Atlas V rocket this week, putting all the pieces in place for liftoff next month with two veteran NASA astronauts on a test flight to the International Space Station.

This will be the first time astronauts fly on Boeing's Starliner crew capsule, following two test flights without crew members in 2019 and 2022. The Starliner Crew Flight Test (CFT) next month will wrap up a decade and a half of development and, if all goes well, will pave the way for operational Starliner missions to ferry crews to and from the space station.

Starliner is running years behind schedule and over budget. SpaceX's Crew Dragon spacecraft has flown all of NASA's crew rotation missions to the station since its first astronaut flight in 2020. But NASA wants to get Boeing's spacecraft up and running to have a backup to SpaceX. It would then alternate between Starliner and Crew Dragon for six-month expeditions to the station beginning next year.

Atlas meets Starliner

Preparations for the first Starliner crew flight reached a significant milestone Tuesday when the spacecraft rolled out of its hangar at NASA's Kennedy Space Center. After emerging from the hangar before dawn, the transporter carrying the spacecraft paused outside the building for a brief photo opportunity with NASA astronauts Butch Wilmore and Suni Williams.

A couple of hours later, the transporter arrived at ULA's Vertical Integration Facility (VIF), the towering hangar where workers stacked Starliner's Atlas V rocket earlier this year. A crane lifted the Boeing crew capsule on top of the Atlas V, capping assembly of the 172-foot-tall (52-meter) rocket.

Wilmore and Williams are in the final stages of training for the test flight, set for launch May 6 at 10:34 pm EDT (02:34 UTC on May 7) from Cape Canaveral Space Force Station. They will fly Starliner to the space station for a stay of about one week, before returning the spacecraft to a parachute-assisted, airbag-cushioned landing in the Western United States, likely at White Sands, New Mexico.

With the launch of Wilmore and Williams aboard Starliner, the United States will have two human-rated spaceships operating at the same time for the first time in the history of the space program. SpaceX's fleet of Crew Dragons have been flying astronauts since 2020, and one is currently docked at the International Space Station.

Over the last few weeks, Boeing technicians loaded propellant into the spacecraft for Starliner's maneuvering thrusters. The Starliner spacecraft for the CFT mission consists of a reusable crew module named Calypso that flew in orbit on the program's first unpiloted test flight in December 2019. The service module, which sits below the crew module, is designed for one mission and hosts the spacecraft's solar arrays, launch-abort engines, and orbital maneuvering thrusters.

Now that Starliner is attached to its Atlas V rocket, ULA and Boeing engineers will run tests to ensure solid mechanical, electrical, and communication links between the spacecraft and launch vehicle. Next week, Wilmore and Williams will return to Cape Canaveral from their training base in Houston for final reviews and training.

These final activities will include a dress rehearsal for launch day. The astronauts will put on their blue pressure suits and climb into their seats aboard Starliner while the rocket and spacecraft remain nestled inside ULA's vertical hangar.

Meanwhile, in orbit, a SpaceX Cargo Dragon spacecraft is scheduled to depart the space station later this month. A few days later, four of the space station crew will fly their Crew Dragon capsule from its current docking port to the location made available by the unlocking of the Cargo Dragon. This will clear the space station's forward docking port for arrival of Starliner next month.

On the eve of liftoff, ULA will roll Atlas V and Starliner one-third of a mile from the VIF out to Space Launch Complex-41 (SLC-41). Once Atlas V is in place at the launch pad, teams will ready the rocket for tanking ahead of the late-night launch May 6.

A season for scrutiny

While ground teams put the final touches on Starliner, NASA and Boeing managers are participating in a series of reviews to formally clear the spacecraft for the Crew Flight Test. This week, NASA's commercial crew program convened a flight test readiness review in Houston.

Next week, top officials from across NASA will hold a flight readiness review at Kennedy Space Center. Assuming officials decide to proceed with the Crew Flight Test, senior managers will certify Starliner is ready to fly with people onboard.

Members of NASA's Aerospace Safety Advisory Panel (ASAP) are sitting in on these reviews. Congress set up the independent panel in 1968 to advise NASA on safety matters. For years, ASAP members have tracked the technical problems that plagued the Starliner program, including software woes, valve corrosion, and most recently, flammable material inside the spacecraft and parachutes that didn't measure up to design specifications. Engineers have resolved those problems to the satisfaction of NASA managers.

“Now that the launch date is nearly here, the panel itself, we have stepped up our fact finding in line with NASA’s prelaunch activity," said Susan Helms, a retired Air Force general, former astronaut, and now chair of the safety panel.

"Over the next couple of weeks before launch, should any concerns arise on our part, NASA leadership has already made it crystal clear they would like us to raise those concerns to them directly and immediately," Helms said.

During the panel's quarterly meeting Wednesday, Helms said it appears NASA has "robustly discussed" and "comprehensively addressed" risks with the Starliner test flight.

“In summary, with just a few weeks before this launch, it’s the panel’s view that NASA has an appropriate, mature risk management framework in place to address the challenges of the Crew Flight Test of the Starliner, and that NASA’s safety culture appears to be healthy and equal to the task at hand," she said.

Wilmore, the commander of Starliner's Crew Flight Test, told Ars last month that outside observers should not expect perfection on the spacecraft's first flight with people. "Don’t have that expectation, please," he said. "It’s not going to be perfect. But it’s not going to be bad, either. We wouldn’t go if we thought that."

The CFT mission will be only the sixth time in more than 60 years that a US-made orbital-class spacecraft makes its debut flight with astronauts, following Mercury, Gemini, Apollo, the Space Shuttle, and Crew Dragon.

“This is a test flight, and a complicated one at that, and as with any test flight, NASA and Boeing should be prepared for contingencies and for flight situations that may stretch the current operating envelope of the Starliner vehicle," Helms said.