India's Mars Orbiter achieves new Milestone in successful Orbital Insertion

[saramath]

The Indian Mars Orbiter Spacecraft achieved a major milestone on Wednesday, successfully inserting itself into orbit around planet Mars, marking the completion of a 680-million Kilometer journey through the Solar System. This marks one of the biggest achievements of the Indian Space Research Organization as MOM ventured further into space than any previous Indian spacecraft.

Successfully placing a spacecraft in orbit around Mars, ISRO becomes the fourth member in an exclusive club of agencies that successfully sent spacecraft to Mars following the Soviet space program, the European Space Agency and NASA that had just sent itsMAVEN spacecraft into Martian orbit on Monday.

Launched back on November 5, 2013 atop a Polar Satellite Launch Vehicle, the Mars Orbiter was constrained by the performance of India's workhorse launcher that required the spacecraft to take the scenic route - first entering an elliptical Earth orbit that the spacecraft raised by making six engine burns before firing its main engine, the Liquid Apogee Motor, a seventh time to depart Earth and enter a path to Mars on November 30.

Image: ISRO

Spending several weeks in Earth orbit allowed MOM to complete detailed checkouts without the effect of a long communications delay. Once on its way to Mars, the orbiter went through more testing and began to fine-tune its path by making an initial Trajectory Correction on December 11 followed by a second maneuver on June 11 that put the spacecraft on a precise path to Mars that was only modified once more on Monday to set up the planned periapsis passage and orbital insertion conditions.

The Indian Space Research Organization sent the commands for the Mars Orbit Insertion Sequence to the MOM spacecraft on September 14/15 to leave sufficient time for validation of the crucial sequence that had no room for error.

Image: ISRO

One of the biggest unknowns of the orbital insertion maneuver was the performance of the Liquid Apogee Motor and the propellant system that, by design, was only built to operate for a few weeks and not sit idle for 295 days before a re-start. To mitigate the issue of leaky valves due to the corrosive nature of the propellants, MOM is equipped with two sets of propellant lines, valves and regulators. The first set was used for orbit-raising and the first trajectory correction before being isolated using pyro valves. Also utilizing pyro valves, the second set of lines was primed in the days leading up to MOI.

To test out the engine and the second set of propellant lines, the Mission Team implemented a Trajectory Correction that was performed on Monday to serve as a test of the LAM and also refine MOM's course to Mars. Using a minimal burn duration of under four seconds, the firing delivered just enough data points to allow teams to assess the operational fuel flow and thrust conditions of the engine - confirming that LAM was working.

Successfully conducting the mission's third TCM, the spacecraft lowered its periapsis attitude from 723 Kilometers to just over 500 Kilometers, optimizing the orbital insertion conditions in order to reach its planned orbit.

With renewed confidence in the LAM engine, ISRO approved their Mars Orbiter to use "Plan A" to enter orbit - firing the 440-Newton LAM instead of reverting to the smaller 22-Newton Attitude Control Thrusters that would have been put to use in case LAM was not operational.

MOM entered the Martian Sphere of influence at 1 UTC on Monday, passing the 577,000-Kilometer-mark as Martian gravity became the primary force acting on the spacecraft.

MOM was left on its own throughout the days leading up to MOI, only operating essential systems and running pre-loaded commands, not requiring any more interaction with Earth. However, the craft continued sending telemetry received by NASA's Deep Space Network Stations and ISRO's tracking station in Bangalore.

Tensions were rising at the Mission Control Center as the Mars Orbiter approached the final crucial steps leading up to MOI. The critical sequence picked up three hours ahead of ignition when the vehicle switched from its directional High Gain Antenna to the Medium Gain Antenna in preparation for the re-orientation to the burn attitude that pointed the HGA boresight off Earth.

On Wednesday, signals from Mars traveled 12 minutes and 28 seconds before arriving at Earth where they were received by NASA's Stations in Canberra and Goldstone, being immediately relayed to ISRO to track the progress of their spacecraft via status telemetry and doppler tracking.

At MOI-21 minutes, the spacecraft began the re-orientation to its retrograde burn attitude, pointing LAM forward to be able to slow down and get captured in orbit. This attitude maneuver used MOM's reaction wheels and was completed as planned, indicated by telemetry from the navigation platform of the vehicle. Five minutes ahead of ignition, the spacecraft passed into the Martian shadow, entering eclipse for the first time since leaving Earth orbit.

Three minutes before MOI, the vehicle handed from the reaction wheels to the eight 22-Newton thrusters for attitude control.

At 1:47:32 UTC, the Liquid Apogee Motor ignited on one of the most important burns performed by any LAM to date since most missions have backup plans and margin for error, but India's Mars Orbiter did not have that luxury - to get into orbit around Mars, there was only one chance. Signals confirming LAM's ignition and it reaching operational conditions arrived on Earth at 2:00 UTC.

Image: ISRO

Image: ISRO

The Mission Control team was able to track MOM's progress until four minutes and 18 seconds after ignition when the spacecraft disappeared behind Mars, causing a 23-minute loss of signal. Without signal from Mars, tensions at Mission Control peaked as teams could only hope that their spacecraft was behaving well while in occultation.

Photo: ISRO

Delta-v progress until Mars Occultation

The Mars Orbit Insertion Burn had a planned change in velocity of 1,098.7 meters per second with an anticipated burn time of 24 minutes and 14 seconds. However, engine shutdown was triggered by the navigation system when accelerometers sensed that the proper delta-v was achieved, dynamically adjusting for actual engine performance by extending of shortening the burn slightly.

For MOM, the sun came up 19.5 minutes into its burn, but Earth was not coming into view until three minutes after the scheduled end of the Mars Orbit Insertion burn. The spacecraft was programmed to start the re-orientation back to its comm attitude one minute after shutdown, followed five minutes later by the re-activation of the communications system when MOM was visible from Earth again.

Anxiously awaiting the signal of the spacecraft, Mission Controllers were standing by as the first pieces of data arrived after traveling 224 million Kilometers through space. Loud applause and cheering emerged when initial data indicated that MOM reached the full burn duration with an achieved delta-v of 1,099m/s. ISRO provided the actual burn duration as 23 minutes and 8.67 seconds, indicating a slight overperformance of the engine that was automatically corrected by shortening the burn.

Initial doppler tracking also pointed to a successful orbital insertion, however, it took several hours of tracking until the exact orbit of the Mars Orbiter could be determined. MOM was targeting an insertion orbit of 423 by 80,000 Kilometers inclined 150 degrees and reached a 421.7 by 76,993.6-Kilometer orbit illustrating the accuracy of the spacecraft's insertion maneuver when looking at the periapsis (the slightly lower apoapsis is no problem and will likely prove favorable for science operations).

The orbit has a period of 72 hours, 51 minutes and 51 seconds.

Just like the rest of its mission, this orbit is constrained by propellant availability. Having already consumed the majority of its propellant load to get to Mars, MOM consumed another 250kg of propellant during orbital insertion, leaving just around 40 Kilograms for orbit adjustments and reaction wheel desats, becoming the limiting consumable of the mission.

A lower orbit that would have been benefiting the science return would have required a longer MOI burn which was not possible given the performance limitation of PSLV.

Photo: ISRO

Image: ISRO

Now in orbit, the MOM spacecraft will complete a series of reconfigurations to transition to science operations using its five instruments.

If everything goes according to plan, the first picture of Mars taken by the craft's color camera should arrive on Earth later on Wednesday. The other instruments will complete several days of calibration and checkout before MOM can begin science operations that had been identified as a secondary goal of the mission from the very beginning.

The goal of the Mars Orbiter Mission was primarily to serve as a pathfinder.

Being the first mission of this nature for ISRO, the aim of MOM was to demonstrate the construction of a spacecraft capable of cruising through the solar system and entering orbit around another body, also focusing on mission operations such as navigation, trajectory planning, spacecraft maintenance and the autonomous execution of the mission due to long communication delays. Most of these objectives were fulfilled with Wednesday's orbital insertion, but the operation of the spacecraft in orbit with the bonus of science operations is another milestone ISRO aims to complete.

Image: ISRO

Five instruments are installed on the MOM spacecraft to conduct a number of scientific studies with focus on the Martian atmosphere and the planet's topography. The Lyman-Alpha Photometer will be used to measure the Deuterium-to-Hydrogen ratio in the atmosphere which can serve as tracer for atmospheric loss processes that played an extremely important role in the evolution of planet Mars.

MENCA, the Martian Exospheric Neutral Composition Analyzer is a quadrupole mass spectrometer that will be used to study the composition of the outermost layers of the Martian atmosphere, tracking even minute variations of its composition over time. The Methane Sensor for Mars will support the ongoing search for Methane on Mars as a specialized instrument to detect Methane down to a concentration of a few parts per billion.

TIS, the Thermal Infrared Imaging Spectrometer, will track thermal emissions from the Martian surface to deduce surface composition and mineralogy while the Mars Color Camera delivers visible imagery of the surface for an assessment of the Martian topography.

ISRO hopes to operate the Mars Orbiter Spacecraft for at least 160 days in orbit around Mars, but the mission is open-ended and will continue as long as the spacecraft continues to function, paving the way for future missions to distant targets.

Image: ISRO

Image: NASA JPL Solar System Simulator

source-http://www.spaceflight101.com/mars-orbiter-mission-updates.html

UPDATE

Image of Mars tweeted by Mangalyaan from its official Twitter handle. Photograph: @marsorbiter/Twitter

[dcs18]

A truly commendable feat by the Indian scientists as they achieved it on the very first try - moreover, the total expenditure incurred was the lowest of its kind.

[windowsvistas]

Proud To Be An Indian :wub:

Next is 4 Ton Payload Launch

And After That Manned Mission to Moon :showoff:

[OrioNeXus]

Superb Achievements Hurray and Cheers for the Scientists ^_^