WASHINGTON — India’s newly launched Mars orbiter, Mangalyaan, underperformed the fourth of a planned six orbit-raising maneuvers necessary to boost the spacecraft out of Earth’s orbit and on its way to the red planet by Dec. 1, according to a Nov. 11 statement from the Indian Space Research Organisation (ISRO).
A “supplementary” orbit-raising maneuver is now planned for Nov. 12, according to the statement.
Mangalyaan, a 1.3-ton orbiter launched Nov. 5 atop an Indian Polar Satellite Launch Vehicle, successfully completed three orbit-raising maneuvers prior to a Nov. 11 attempt that was cut short by a propulsion glitch. As a result, the spacecraft picked up an additional 35-meters-per-second of velocity instead of the intended 130 meters-per-second gain and raised its apogee — the highest point of its highly elliptical orbit — some 6,600 kilometers to 78,276 kilometers, well short of the day’s 100,000-kilometer target altitude.
ISRO’s original timeline called for booting Mangalyaan’s apogee to 192,000 kilometers by Dec. 1, at which time it would break free from Earth’s gravitational pull and begin its nine-month journey to Mars.
ISRO did not say whether the supplementary maneuver planned for Nov. 12 would impact that timeline.
Here’s ISRO’s full statement:
Supplementary Orbit Raising Manoeuvre Planned for Mars Orbiter Spacecraft
In the fourth orbit-raising operation conducted this morning (Nov 11, 2013), the apogee (farthest point to Earth) of Mars Orbiter Spacecraft was raised from 71,623 km to 78,276 km by imparting an incremental velocity of 35 metres/second (as against 130 metres/second originally planned to raise apogee to about 100,000 [1 lakh] km). The spacecraft is in normal health. A supplementary orbit-raising operation is planned tomorrow (November 12, 2013) at 0500 hrs IST to raise the apogee to nearly 1 lakh km.
During the orbit-raising operations conducted since November 7, 2013, ISRO has been testing and exercising the autonomy functions progressively, that are essential for Trans-Mars Injection (TMI) and Mars Orbit Insertion (MOI).
During the first three orbit-raising operations, the prime and redundant chains of gyros, accelerometers, 22 Newton attitude control thrusters, attitude and orbit control electronics as well as the associated logics for their fault detection isolation, and reconfiguration have been exercised successfully. The prime and redundant star sensors have been functioning satisfactorily. The primary coil of the solenoid flow control valve was used successfully for the first three orbit-raising operations.
During the fourth orbit-raising operations held today (November 11, 2013), the redundancies built-in for the propulsion system were exercised, namely, (a) energising the primary and redundant coils of the solenoid flow control valve of 440 Newton Liquid Engine and (b) logic for thrust augmentation by the attitude control thrusters, when needed. However, when both primary and redundant coils were energised together, as one of the planned modes, the flow to the Liquid Engine stopped. The thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters. This sequence resulted in reduction of the incremental velocity.
While this parallel mode of operating the two coils is not possible for subsequent operations, they could be operated independently in sequence.
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