November 12, 2013
A day after an engine anomaly slowed its progress, India’s Mars Orbiter successfully raised its orbit to an apogee above 118,000 km (73,000 mi.) on Nov. 12.
The country’s first Mars orbiter suffered a setback on Nov. 11 as attempts were made to raise the spacecraft’s orbit around Earth to built momentum for its trip to Mars. A minor problem with the liquid fuel thruster caused the 1,350-kg (3,000-lb.) vehicle to fall short of the mark.
“The fourth supplementary orbit-raising maneuver of Mars Orbiter Spacecraft, starting at 05:03 local time, with a burn time of 303.8 seconds has been successfully completed,” Indian Space Research Organization (ISRO) spokesman Deviprasad Karnik says. “The observed change in apogee is from 78,276 km to 118,642 km.”
The velocity added to the Mars Orbiter was 124.9 meters per second. “Everything is normal,” Karnik tells Aviation Week.
The Mars Orbiter Mission (MOM) was boosted by a Polar Satellite Launch Vehicle (PSLV-C25) from the Sriharikota spaceport in south India on Nov. 5. Over the next 10 days, scientists at the ISRO are scheduled to raise the apogee of the orbiter to around 200,000 km (120,000 mi.) in preparation for leaving Earth orbit and reaching Mars by September 2014.
On Nov. 11 the maneuver to raise the apogee of the “Maangalyaan” probe from 71,623 km to 100,000 km could only achieve 78,276 km, since the incremental velocity imparted to the spacecraft was only 35 m/s against a targeted 130 m/s, the spokesman says. This was the first orbit-raising move to fall short of the objective after three successful burns in a series of five, known as “midnight maneuvers,” that began following the launch.
While conducting the orbit-raising operations since Nov. 7, ISRO scientists have been testing and exercising other functions essential for Trans-Mars Injection and Mars Orbit Insertion.
During the first three orbit-raising operations, mission controllers successfully exercised the spacecraft’s prime and redundant chains of gyros, accelerometers, 22-Newton attitude control thrusters, and attitude and orbit control electronics, as well as the associated logics for their fault detection isolation and reconfiguration, ISRO says.
“The prime and redundant star sensors have been functioning satisfactorily,” an ISRO official adds. “The primary coil of the solenoid flow control valve was used successfully for the first three orbit-raising operations.”