ISRO Mars Orbiter Mission (MOM) came in for a momentary scare on Monday, when routine procedure to check for all eventualities shut out the supply of fuel to the engine at the start of the fourth orbit raising manoeuvre. The moment, however, became an unintentional but successful demonstration of a technology that would prove critical to the mission’s success.
Later in the day, ISRO announced that it will perform a previously unscheduled supplementary orbit raising manoeuvre to bring the mission back on schedule.
The incident occurred when the Spacecraft Command Centre in Bangalore charged both the primary and back-up solenoid coils as part of routine procedures to check their functioning.
The solenoid valve, which controls the flow of liquid propellant to the main 440 Newton engine of the Mars Orbiter, shut down the fuel supply as a result of this. Both the primary and the redundancy coils had been fired separately with success previously, but failed to work together.
A supplementary operation has been planned for Tuesday morning in order to achieve the target. However, ISRO maintained that all systems were normal and that the Mars Orbiter Mission was on track.
In a statement, ISRO said the original operation planned to fire the engine to impart an incremental velocity of 130 metres per second. Instead, scientists restricted the velocity to 35 metres per second and achieved an apogee of 78,276 km. The Mars Orbiter’s autonomy is critical to its functioning on its way to Mars, thanks to the fact that the spacecraft may have to fend for itself as it waits for commands from the Spacecraft Command Centre to reach it over the vast distance.
ISRO chief K Radhakrishnan told a news channel in Delhi the spacecraft encountered “a problem” during a specific redundancy test, and that the spacecraft “failed to reach the desired velocity”.