Mars orbiter bounces back; raring to go at 1.18 lakh kilometres - The Times of India
CHENNAI: India's first Mars orbiter spacecraft bounced back into action after a day of concern, when Isro scientists raised its apogee (farthest point from Earth) to more than 1 lakh kilometres on Tuesday.
"The orbit-raising operation was a success, " Isro chairman K Radhakrishnan messaged TOI early on Tuesday. "We are expecting an apogee of 1.18 lakh km." This means that the spacecraft is ready to leave Earth's orbit. This exercise, called the trans-Martian injection is planned on December 1.
On Monday, a halt in the flow of the liquid engine had slowed down the orbit-raising operation, as an apogee of only 71,623km could be achieved as against the desired orbit of 1 lakh km. This was corrected with Tuesday's exercise.
What saved the spacecraft were the redundancies (back-up systems) on board the spacecraft.
"When both the 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 incremental velocity," Isro said in a statement.
Scientists said the spacecraft is in good health to achieve its objectives including the trans-Martian injection on December 1, and the 400-million km cruise to the red planet in 300 days.
"During the orbit-raising operations conducted since November 7, 2013, Isro has been testing and exercising the autonomy functions progressively. 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," Isro said.
The drawback means the planned simultaneous operation of two coils would not be possible anymore, but if the rest of the operations happen as planned, the spacecraft will reach the Martian orbit on September 24.
Success! ISRO raises Mars orbiter beyond 1 lakh km apogee | Firstpost
Chennai: A day after suffering a glitch during the fourth orbit raising operation on its Mars Orbiter Mission, ISRO today successfully completed the supplementary manoeuvre this morning, raising the spacecraft’s apogee (farthest distance from Earth) to over 1,18,000 km.
“The fourth supplementary orbit raising manoeuvre of Mars Orbiter spacecraft started at 5.03 AM (IST) with a Burn Time of 303.8 seconds and it has been successfully completed. The observed change in apogee is from 78,276 km to 1,18,642 km,” ISRO said.
The supplementary manoeuvre, which was completed by 5.10 AM, added a velocity of 124.9 m/s to the spacecraft, it said.
After suffering a glitch during the fourth orbit raising operation yesterday, ISRO planned for a supplementary manoeuvre at 5 AM to achieve the targeted apogee of one lakh km.
PTI
The fifth of the five orbit raising operation to raise the spacecraft’s apogee of over 1,92,000 km is scheduled for 16 November.
During the fourth orbit raising operations yesterday, the 440 Newton liquid engine stopped, while both primary and redundant coils were energised together, however the thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters and the spacecraft was “normal” and “100 per cent safe,” according to ISRO.
Following the glitch, the apogee was raised only to 78,276 km against the target of about one lakh km.
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 were exercised successfully.
After successfully completing these operations, the mission is expected to take on the “crucial event” of the trans-Mars injection around 12:42 AM on 1 December.
ISRO’s PSLV C 25 successfully injected the 1,350-kg Mangalyaan Orbiter (Mars craft) into orbit around Earth some 44 minutes after a textbook launch at 2:38 PM from Satish Dhawan Space Centre at Sriharikota on Tuesday last, marking the successful completion of the first stage of the Rs 450-crore mission.
CHENNAI: India's first Mars orbiter spacecraft bounced back into action after a day of concern, when Isro scientists raised its apogee (farthest point from Earth) to more than 1 lakh kilometres on Tuesday.
"The orbit-raising operation was a success, " Isro chairman K Radhakrishnan messaged TOI early on Tuesday. "We are expecting an apogee of 1.18 lakh km." This means that the spacecraft is ready to leave Earth's orbit. This exercise, called the trans-Martian injection is planned on December 1.
On Monday, a halt in the flow of the liquid engine had slowed down the orbit-raising operation, as an apogee of only 71,623km could be achieved as against the desired orbit of 1 lakh km. This was corrected with Tuesday's exercise.
What saved the spacecraft were the redundancies (back-up systems) on board the spacecraft.
"When both the 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 incremental velocity," Isro said in a statement.
Scientists said the spacecraft is in good health to achieve its objectives including the trans-Martian injection on December 1, and the 400-million km cruise to the red planet in 300 days.
"During the orbit-raising operations conducted since November 7, 2013, Isro has been testing and exercising the autonomy functions progressively. 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," Isro said.
The drawback means the planned simultaneous operation of two coils would not be possible anymore, but if the rest of the operations happen as planned, the spacecraft will reach the Martian orbit on September 24.
Success! ISRO raises Mars orbiter beyond 1 lakh km apogee | Firstpost
Chennai: A day after suffering a glitch during the fourth orbit raising operation on its Mars Orbiter Mission, ISRO today successfully completed the supplementary manoeuvre this morning, raising the spacecraft’s apogee (farthest distance from Earth) to over 1,18,000 km.
“The fourth supplementary orbit raising manoeuvre of Mars Orbiter spacecraft started at 5.03 AM (IST) with a Burn Time of 303.8 seconds and it has been successfully completed. The observed change in apogee is from 78,276 km to 1,18,642 km,” ISRO said.
The supplementary manoeuvre, which was completed by 5.10 AM, added a velocity of 124.9 m/s to the spacecraft, it said.
After suffering a glitch during the fourth orbit raising operation yesterday, ISRO planned for a supplementary manoeuvre at 5 AM to achieve the targeted apogee of one lakh km.
PTI
The fifth of the five orbit raising operation to raise the spacecraft’s apogee of over 1,92,000 km is scheduled for 16 November.
During the fourth orbit raising operations yesterday, the 440 Newton liquid engine stopped, while both primary and redundant coils were energised together, however the thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters and the spacecraft was “normal” and “100 per cent safe,” according to ISRO.
Following the glitch, the apogee was raised only to 78,276 km against the target of about one lakh km.
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 were exercised successfully.
After successfully completing these operations, the mission is expected to take on the “crucial event” of the trans-Mars injection around 12:42 AM on 1 December.
ISRO’s PSLV C 25 successfully injected the 1,350-kg Mangalyaan Orbiter (Mars craft) into orbit around Earth some 44 minutes after a textbook launch at 2:38 PM from Satish Dhawan Space Centre at Sriharikota on Tuesday last, marking the successful completion of the first stage of the Rs 450-crore mission.
