It seems ISRO was using the redundant paths introduced in the fuel line for this engine firing. Quote it encountered a problem when a specific redundancy test was being conducted and it failed to reach the desired velocity it was to achieve.http://www.ndtv.com/article/india/india-s-mars-mission-hits-first-hurdle-444424
it encountered a problem when a specific redundancy test was being conducted and it failed to reach the desired velocity it was to achieve.
Supplementary Orbit Raising Manoeuvre Planned for Mars Orbiter SpacecraftIn 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.
Quote from: antriksh on 11/11/2013 07:55 amIt seems ISRO was using the redundant paths introduced in the fuel line for this engine firing. Quote it encountered a problem when a specific redundancy test was being conducted and it failed to reach the desired velocity it was to achieve.http://www.ndtv.com/article/india/india-s-mars-mission-hits-first-hurdle-444424Thanks for that. I see that article is again talking about it slingshoting out of Earth orbit.
Was testing the parallel mode intentional to trigger thrust augmentation by attitude control thrusters?
So it sounds like they have 2 fuel lines - a main one and an extra one for backup - and the fuel flow through each is regulated by their respective solenoid valve. So as a systems check, they tried to use the main fuel line / flow valve and that worked, then they tried to use the backup fuel line / flow valve and that worked, but when they tried to use both fuel lines / flow valves at the same time, then that resulted in a stoppage of the fuel flow to the rocket motor and its shutoff.The automatic thrust augmentation logic then kicked in to restart the motor, however the resulting orbit achieved was only 78K km instead of 100K km.So what they've learned from this is that they cannot use both valves / fuel lines together at the same time.I wonder why. Is it a pressure issue? Maybe they can't get the required pressure to push enough fuel through, if both valves are open instead of just either one?Isn't this something that should have been tested on the ground first? I recall reading that ISRO did not build a duplicate mockup of the spacecraft for testing on the ground, but only tested using software simulations. Maybe this is something which would have turned up had they tested on a physical duplicate of the spacecraft.
“The satellite’s engine doesn’t work when both coils are simultaneously on,” a spokesman for the ISRO told The Wall Street Journal.“This is not at all a setback, we got our redundancies [backup plans] checked by this process,” said the spokesman, who declined to be named. He said it was not necessary for both coils to be on at the same time during the rest of the flight plan.
http://blogs.wsj.com/indiarealtime/2013/11/11/first-hiccup-for-indias-mars-mission/
They have tested propulsion system at sea level and simulated vacuum conditions. What could be use of a mode with both the valves opened?
BTW, from this, it seems it was intentional to test the augmentation logic. But they could have very well regulated the thrust of the main engine to trigger the same logic.
Quote“The satellite’s engine doesn’t work when both coils are simultaneously on,” a spokesman for the ISRO told The Wall Street Journal.“This is not at all a setback, we got our redundancies [backup plans] checked by this process,” said the spokesman, who declined to be named. He said it was not necessary for both coils to be on at the same time during the rest of the flight plan.http://blogs.wsj.com/indiarealtime/2013/11/11/first-hiccup-for-indias-mars-mission/So their are two levels of redundancies for propulsion: 1) first is a redundant fuel line to the main engine that would be used in case the prime fuel line suffers failure and 2) is the use of attitude thrusters for augmentation/provision of thrust. Now we know that the 2nd and the last option can provide 1/3 rd thrust required. Hoping for the best!!
“The satellite’s engine doesn’t work when both coils are simultaneously on,” a spokesman for the ISRO told The Wall Street Journal.“This is not at all a setback, we got our redundancies [backup plans] checked by this process,” said the spokesman, who declined to be named. He said it was not necessary for both coils to be on at the same time during the rest of the flight plan.http://blogs.wsj.com/indiarealtime/2013/11/11/first-hiccup-for-indias-mars-mission/
Mr Bagla told BBC News that the attempt on Monday morning used up about 2kg of the craft's 852kg fuel load.But Mr Bagla added that the spacecraft's insertion into Earth orbit after launch on 5 November had been so precise, 6kg of liquid fuel had been saved. Even with Monday's glitch, the mission still had a fuel surplus of 4kg.
http://www.bbc.co.uk/news/science-environment-24900271QuoteMr Bagla told BBC News that the attempt on Monday morning used up about 2kg of the craft's 852kg fuel load.But Mr Bagla added that the spacecraft's insertion into Earth orbit after launch on 5 November had been so precise, 6kg of liquid fuel had been saved. Even with Monday's glitch, the mission still had a fuel surplus of 4kg.Okay, so they're still ahead of the game
Quote from: sanman on 11/11/2013 01:52 pmhttp://www.bbc.co.uk/news/science-environment-24900271QuoteMr Bagla told BBC News that the attempt on Monday morning used up about 2kg of the craft's 852kg fuel load.But Mr Bagla added that the spacecraft's insertion into Earth orbit after launch on 5 November had been so precise, 6kg of liquid fuel had been saved. Even with Monday's glitch, the mission still had a fuel surplus of 4kg.Okay, so they're still ahead of the gameIt seems to me it was really good to find this problem in Earth orbit. Typically, planetary injection firings use all possible redundancy, since they are mission critical and can't be fixed from the ground, due to delays. So I suspect the normal Mars-insertion mode would have been both coils/valves energized. If so, and if the same problem re-occurred, it would be fatal to the mission.So at least now they can re-program the burn to be try A, then if that does not work, try B. MUCH better to find this now, rather than when you try to insert around Mars!
ISRO's Mars Orbiter Mission6 minutes agoMOM’s Midnight Manoeuvers !The supplementary orbit raising manoeuver of ISRO's Mars Orbiter Mission spacecraft, to raise the apogee height to about 1 lakh km completed successfully.
Fourth supplementary orbit raising manoeuvre of Mars Orbiter Spacecraft, starting at 05:03:50 hrs(IST) on Nov 12, 2013, with a burn Time of 303.8 seconds has been successfully completed.The observed change in Apogee is from 78276km to 118642km.
Question: Could you please check with ISRO whether energizing primary and redundant coils TOGETHER is a mandatory requirement for successful MOI? Now that this mode is ruled out, is ISRO confident of achieving MOI by energizing ONLY ONE COIL AT A TIME (either the primary, or redundant)? Thanks.ISRO's Mars Orbiter Mission: energizing primary and redundant coils together is not a mandatory requirement for MOI or any other phase.
here's an update from http://isro.org/mars/updates.aspx:QuoteFourth supplementary orbit raising manoeuvre of Mars Orbiter Spacecraft, starting at 05:03:50 hrs(IST) on Nov 12, 2013, with a burn Time of 303.8 seconds has been successfully completed.The observed change in Apogee is from 78276km to 118642km.
Quote from: vyoma on 11/12/2013 02:42 amhere's an update from http://isro.org/mars/updates.aspx:QuoteFourth supplementary orbit raising manoeuvre of Mars Orbiter Spacecraft, starting at 05:03:50 hrs(IST) on Nov 12, 2013, with a burn Time of 303.8 seconds has been successfully completed.The observed change in Apogee is from 78276km to 118642km.Excellent news! The next opportunity for a burn near perigee (one orbit later than this) appears to be around 46h45m later. That's almost two days, so ~02:45 IST on Nov 14, if my spreadsheet calculations are correct. It would be great to get a confirmation of that timing from ISRO, though!
Next burn early morning 16th. Now waiting for colored Earth shots!!