Rocket Report: North Korean rocket explosion; launch over Chinese skyline

Welcome to Edition 6.46 of the Rocket Report! It looks like we will be covering the crew test flight of Boeing's Starliner spacecraft and the fourth test flight of SpaceX's giant Starship rocket over the next week. All of this is happening as SpaceX keeps up its cadence of flying multiple Starlink missions per week. The real stars are the Ars copy editors helping make sure our stories don't use the wrong names.

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.

Another North Korean launch failure. North Korea's latest attempt to launch a rocket with a military reconnaissance satellite ended in failure due to the midair explosion of the rocket during the first-stage flight this week, South Korea's Yonhap News Agency reports. Video captured by the Japanese news organization NHK appears to show the North Korean rocket disappearing in a fireball shortly after liftoff Monday night from a launch pad on the country's northwest coast. North Korean officials acknowledged the launch failure and said the rocket was carrying a small reconnaissance satellite named Malligyong-1-1.

Russia's role? ... Experts initially thought the pending North Korean launch, which was known ahead of time from international airspace warning notices, would use the same Chŏllima 1 rocket used on three flights last year. But North Korean statements following the launch Monday indicated the rocket used a new propulsion system burning a petroleum-based fuel, presumably kerosene, with liquid oxygen as the oxidizer. The Chŏllima 1 rocket design used a toxic mixture of hypergolic hydrazine and nitrogen tetroxide as propellants. If North Korea's statement is true, this would be a notable leap in the country's rocket technology and begs the question of whether Russia played a significant role in the launch. Last year, Russian President Vladimir Putin pledged more Russian support for North Korea's rocket program in a meeting with North Korean leader Kim Jong Un. (submitted by Ken the Bin and Jay500001)

Rocket Lab deploys small NASA climate satellite. Rocket Lab is in the midst of back-to-back launches for NASA, carrying identical climate research satellites into different orbits to study heat loss to space in Earth’s polar regions. The Polar Radiant Energy in the Far-InfraRed Experiment (PREFIRE) satellites are each about the size of a shoebox, and NASA says data from PREFIRE will improve computer models that researchers use to predict how Earth’s ice, seas, and weather will change in a warming world. "The difference between the amount of heat Earth absorbs at the tropics and that radiated out from the Arctic and Antarctic is a key influence on the planet’s temperature, helping to drive dynamic systems of climate and weather," NASA said in a statement.

Twice in a week... NASA selected Rocket Lab's Electron launch vehicle to deliver the two PREFIRE satellites into orbit on two dedicated rides rather than launching at a lower cost on a rideshare mission. This is because scientists want the satellites flying at the proper alignment to ensure they fly over the poles several hours apart, providing the data needed to measure how the rate at which heat radiates from the polar regions changes over time. The first PREFIRE launch occurred on May 25, and the next one is slated for May 31. Both launches will take off from Rocket Lab's base in New Zealand. (submitted by Ken the Bin)

A rocket launch comes to Rizhao. China has diversified its launch sector over the last decade to include new families of small satellite launchers and new spaceports. One of these relatively new small rockets, the solid-fueled Ceres 1, took off Wednesday from a floating launch pad positioned about 2 miles (3 km) off the coast of Rizhao, a city of roughly 3 million people in China's Shandong province. The Ceres 1 rocket, developed by a quasi-commercial company called Galactic Energy, has previously flown from land-based launch pads and a sea-borne platform, but this mission originated from a location remarkably close to shore, with the skyline of a major metropolitan area as a backdrop.

Range safety ... There's no obvious orbital mechanics reason to position the rocket's floating launch platform so near a major Chinese city, other than perhaps to gain a logistical advantage by launching close to port. The Ceres 1 rocket has a fairly good reliability record—11 successes in 12 flights—but for safety reasons, there's no Western spaceport that would allow members of the public (not to mention a few million) to get so close to a rocket launch. For decades, Chinese rockets have routinely dropped rocket boosters containing toxic propellant on farms and villages downrange from the country's inland spaceports.

Avio test-fires Vega C rocket motor. The European Space Agency says a successful test firing of a redesigned Vega C solid rocket motor is a major step toward returning the rocket to flight by the end of the year, Space News reports. Avio, the prime contractor for the Vega C, conducted a static-fire test of the redesigned Zefiro-40 motor on May 28 at a company test facility in Italy. The motor, used as the second stage of the Vega C, fired for 94 seconds, as expected. The Zefiro-40 motor was implicated in the failure of the second Vega C rocket in December 2022, which an investigation blamed on faulty carbon-carbon material used in the motor’s nozzle.

The long road to flight ... Avio found a new supplier for the carbon-carbon material, but the nozzle failed in a static fire test in June 2023. This prompted Avio to redesign the nozzle itself, according to Space News. This fall, Avio plans a second static test-firing of the Zefiro-40 motor ahead of the Vega C rocket's return to flight mission at the end of the year. The grounding of the Vega C rocket and delays with Europe's new Ariane 6 rocket have left the continent largely without independent access to space, forcing ESA to move some payloads to SpaceX's Falcon 9 rocket. One more flight of the basic version of the Vega rocket, which doesn't use the Zefiro-40 motor, is planned for September. (submitted by Ken the Bin and EllPeaTea)

Indian startup celebrates suborbital launch. Agnikul Cosmos, a space tech startup, successfully launched a single-stage rocket Thursday on a test flight to gather data for a future rocket to place small satellites into low-Earth orbit, the Times of India reported. The suborbital technology demonstrator for the Agnibaan rocket lifted off from a private launch pad at the Indian space agency's government-owned Satish Dhawan Space Center and was supposed to fly to an altitude of approximately 20 kilometers. In a post on X, Agnikul Cosmos said it successfully completed the flight. "All the mission objectives of this controlled vertical ascent flight were met and performance was nominal," the company said. "The vehicle was completely designed in-house and was powered by the world’s first single piece 3D-printed engine, and also happens to be India’s first flight with a semi-cryo engine."

Precursor to an orbital launch ... The semi-cryogenic engine burns a mix of jet fuel and super-cold liquid oxygen propellants, and is similar to the seven 5,600-pound thrust engines Agnikul Cosmos plans to cluster on its orbital-class Agnibaan rocket. The privately developed Agnibaan will be capable of putting a payload of about 220 pounds (100 kilograms) into low-Earth orbit. Agnikul says it plans to launch the first orbital mission by the end of 2025.

Starliner launch on track for Saturday. Senior managers from NASA and Boeing plan to launch the first crew test flight of the Starliner spacecraft on an Atlas V rocket as soon as June 1, following several weeks of detailed analysis of a helium leak and a "design vulnerability" with the ship's propulsion system, Ars reports. Extensive data reviews since the first Starliner launch attempt on May 6 settled on a likely cause of the leak, which officials described as small and stable. During these reviews, engineers also built confidence that even if the leak worsened, it would not add any unacceptable risk for the Starliner test flight to the International Space Station, officials said.

Flight rationale ... During a flight test readiness review Wednesday, top space agency officials agreed to proceed with the Starliner launch attempt on Saturday. Engineers developed a workaround to overcome the small chance (a special case that would require multiple failures) that a design flaw discovered during testing in recent weeks could prevent the Starliner spacecraft from completing a deorbit burn to head for landing at the end of the test flight. NASA astronauts Butch Wilmore and Suni Williams will be the first crew members to launch on Boeing's Starliner, and they flew to NASA's Kennedy Space Center this week to prepare for their weekend liftoff.

ESA's EarthCARE rides on Falcon 9. The European Space Agency's latest Earth-observing satellite, EarthCARE, launched Tuesday from California on top of a SpaceX Falcon 9 rocket, Spaceflight Now reports. EarthCARE was originally slated to launch on a Russian Soyuz rocket before ESA lost access to Soyuz following Russia's invasion of Ukraine. Europe's Vega C rocket, which could have also launched EarthCARE, has been grounded since 2022 due to a design problem with its second-stage motor. This meant EarthCARE, like several other European space missions, had to launch on a SpaceX rocket or else wait a year or more for a ride on Vega C or Ariane 6.

Clouds and aerosols ... With four laser and radar instruments provided by European and Japanese institutions, the 800 million euro ($870 million) EarthCARE mission will measure how clouds and aerosol particles at different altitudes in Earth's atmosphere influence the climate, the BBC reports. From an altitude of 400 miles (250 km), EarthCARE will take pictures of cloud cover, measure their altitudes, and peer into clouds to determine how much water they are carrying, and how it is precipitating as rain, hail, and snow. A radiometer will sense how much of the energy falling on to Earth from the Sub is being reflected to radiate back into space. (submitted by Ken the Bin and EllPeaTea)

Competitors cry foul over SpaceX's dominance. Leaders from several small launch companies vying to compete with SpaceX had particularly harsh language for the world's leading launch company in a story published this week by The New York Times. In the story, the founders of Rocket Lab, Relativity Space, and Phantom Space—each at very different stages in their rocket programs—appeared to accuse SpaceX of anti-competitive behavior. However, none of these companies currently have a rocket that can compete one on one with SpaceX's workhorse Falcon 9. In fact, only Rocket Lab has an operational rocket at all. Its light-class Electron rocket competes with the Falcon 9 in the small satellite launch market. SpaceX aggregates numerous small satellites on rideshare missions, while the Electron is designed to give these same types of payloads a dedicated ride to orbit.

Not speaking for all ... The co-founder of another small launch startup, ABL Space Systems, took a more nuanced view of SpaceX. "As a founder of a launch company, I disagreed with the thrust of this NYT article," Dan Piemont wrote on X. "I admire SpaceX and welcome their success." It is well worth reading Piemont's entire post, which is too long to cover here in its entirety. Piemont shares his thoughts on SpaceX's pricing strategy for its small satellite rideshare missions (some have accused SpaceX of intentionally under-cutting competitors' prices) and the importance for the US government to have access to multiple launch providers. Also, read Elon Musk's response to Piemont, in which he writes: "To the best of my knowledge, none of the rideshare missions have lost money." (submitted by Ken the Bin and EllPeaTea)

Starship next week. SpaceX is targeting June 5 for the next flight of its massive Starship rocket, pending regulatory approval from the Federal Aviation Administration, Ars reports. The highly anticipated test flight—the fourth in a program to bring Starship to operational readiness and make progress toward its eventual reuse—will seek to demonstrate the ability of the Super Heavy first stage to make a soft landing in the Gulf of Mexico and for the Starship upper stage to make a controlled reentry through Earth's atmosphere before it falls into the Indian Ocean. This mission will carry no payloads as SpaceX seeks additional flight data about the performance of the complex Starship vehicle.

What happened in March? … As part of its announcement of the flight date, SpaceX provided some information about its learnings from the most recent flight test, Flight 3, which launched on March 14, 2024. During that flight, blockage in a filter where liquid oxygen flows into the Raptor engines caused some of them to shut down early during an attempt to steer the Super Heavy booster toward a controlled splashdown in the Gulf of Mexico. The first stage lost control during the final descent. The Starship upper stage reached its planned trajectory on the March test flight, but it lost the ability to control its attitude during a coast phase in space. This prevented SpaceX from conducting a restart test of a Raptor engine in space and led to the ship's uncontrolled reentry into the atmosphere, where it broke apart and burned up over the Indian Ocean.

Next three launches

May 31: Falcon 9 | Starlink 6-64 | Cape Canaveral Space Force Station, Florida | 22:43 UTC

June 1: Electron | PREFIRE 2 | Mahia Peninsula, New Zealand | 03:00 UTC

June 1: Atlas V | Starliner Crew Flight Test | Cape Canaveral Space Force Station, Florida | 16:25 UTC