After having successfully completed three orbit raising manoeuvres, ISRO’s Mars Orbiter mission on Monday suffered a glitch as it failed to achieve the targeted apogee (farthest distance from Earth) of one lakh km during the fourth orbit raising operation in the early hours. However, the national space agency clarified that the Mars Orbiter was ‘normal’ and said a supplementary orbit raising operation has been planned at 5 am (IST) on Tuesday to raise the apogee to nearly one lakh km.
During the fourth orbit raising operations which commenced at 2:06 am on Monday, the redundancies built-in for the propulsion system were exercised, including energising the primary and redundant coils of the solenoid flow control valve of 440 Newton Liquid Engine and logic for thrust augmentation by the attitude control thrusters.
‘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,’ ISRO said in a statement. The space agency said while this parallel mode of operating the two coils was not possible for subsequent operations, they could be operated independently in sequence.
During the fourth orbit raising operations which commenced at 2:06 am on Monday, the redundancies built-in for the propulsion system were exercised, including energising the primary and redundant coils of the solenoid flow control valve of 440 Newton Liquid Engine and logic for thrust augmentation by the attitude control thrusters.
‘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,’ ISRO said in a statement. The space agency said while this parallel mode of operating the two coils was not possible for subsequent operations, they could be operated independently in sequence.