An orbital manoeuvres was performed on Mars Orbiter Mission (MOM) spacecraft to avoid the impending long eclipse duration for the satellite. The duration of the eclipse would have been as long as 8 hours in the coming days. As the satellite battery is designed to handle an eclipse duration of only about 1 Hour 40 minutes, a longer eclipse would have drained the battery beyond the safe limit. The manoeuvres performed on January 17, 2017 brought down the eclipse duration to zero during this long eclipse period.
On the Evening of January 17, all the eight numbers of 22N thrusters were fired for a duration of 431 seconds, achieving a velocity difference of 97.5 m/s. This has resulted in a new orbit for the MOM spacecraft, which completely avoids eclipse up to September 2017. About 20 kg propellant was consumed for this manoeuvres leaving another 13 kg of propellant for its further mission life.
The spacecraft health is normal. The next long eclipse period for MOM is expected in the year 2020.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 25 Jan 2017 02:51
by Varoon Shekhar
^
it does look to the lay viewer, that the apogee of Mangalyaan's new orbit, is lower than the previous orbit. Which is good thing, right?
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 25 Jan 2017 05:44
by disha
^ More circular and tilted towards Sun. Mangalyan will be in this orbit for a while to come and will provide an excellent referential point on various aspects of its engineering design and components.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 25 Jan 2017 06:55
by SriKumar
On the Evening of January 17, all the eight numbers of 22N thrusters were fired for a duration of 431 seconds, achieving a velocity difference of 97.5 m/s. This has resulted in a new orbit for the MOM spacecraft, which completely avoids eclipse up to September 2017. About 20 kg propellant was consumed for this manoeuvres leaving another 13 kg of propellant for its further mission life
Assuming no other orbit maneuvers were performed after Mars orbit insertion, this means that the Mangalyaan's thrusters were fired/activated after a gaps of 2 years 4 months in cold space. That's some reliability for the entire system. Also, I am assuming in this case, the dynamics of this craft would be quite different and more tricky with the antenna and solar panels all deployed (vs the earth orbit raising maneuvers and Mars orbit insertion maneuvers where the craft was not fully 'open').
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 25 Jan 2017 21:45
by Varoon Shekhar
Wouldn't those thrusters be fired every time the spacecraft is about to make an orbit around the planet? For 'correction' purposes?But it is certain that not all of them are ignited so it is still very impressive that they all came "alive" after a long dormancy
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 25 Jan 2017 23:20
by prasannasimha
No everybody keeps its state of rest or motion unless acted upon by an external unopposed force and the only need for thrusters is to correct the attitude. Even when dead MOM will be circling mars for centuries though it will not be able to orient its antenna to transmit data.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 26 Jan 2017 00:40
by Amber G.
Few short comments wrt to comments like "apogee of Mangalyaan's new orbit, is lower than the previous orbit -(Which is good thing, right?) " or "More circular and tilted towards Sun". (What does one really MEAN by "lower" or "tilted towards Sun ?).. I may put some short post later to clear some basic information and geometry.
But practically speaking eclipses are almost unavoidable -- at least one or two every martian year (about 1.9 years) -- unless one spends fuel to reorient the orbit. One can try to make them shorter and less often and that is what one tries to do using what fuel it can use. Lot of thought goes into it and they considered everything to keep this minimum for at least a year at the time of MOI.
The other orbit parameters of Inclination, Right Ascension of Ascending Node and Argument of Perigee were selected after a detailed analysis to meet the following Mission constraints:- maximum eclipse period should be less than 100 min; imaging of Mars full disc from apoapsis region should be possible from Day 1 after MOI; orbit periapsis altitude should be stable at least for one year considering all the perturbative forces. The achievable range of Martian orbit inclination values were found to be from 29 deg to 151 deg in Mars IAU frame of reference, since the declination of the V-infinity of the Mars arrival hyperbola was -29 deg. Seven orbits, two direct, one polar and four retrograde orbits were targeted in the maneuver design and studied with respect to the delta-V cost of achieving the orbit, the sun-orbit geometry after MOI, the eclipse characteristics, orbit stability and imaging opportunities. The star sensor mounting configuration requirement and occult management was also studied for each of the orbits. The retrograde orbit of size 500 x 80000 km, with 151 deg inclination, ascending node of 61 deg and argument of perigee of 206 deg, was found to be the most suitable orbit satisfying all the specified constraints as well as from the viewpoint of star sensor mounting and management of star sensor occults.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 24 Sep 2017 06:06
by Varoon Shekhar
Hey, it's worth mentioning that today/early tomorrow( Sept 24)) marks 3 years that Mangalyaan/MOM has been in orbit around Mars.And it's original lifespan was about 6 months!
Another beauty from Mangalyaan/MOM. And these latest pics are from that new orbit MOM found itself in, after the reorientation( because of an eclipse) ISRO did in Jan/2017
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 20 Mar 2018 00:35
by Amber G.
^^^From a scientist/engineer's point of view, more one reads about details, one gets more and more impressed about the work done by ISRO scientists.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 20 Mar 2018 00:48
by Katare
We need to start naming features at Mars in Sanskrit now........Mars has become westernized all ready..
I have never before seen a picture with such a clear and bright ice clouds on Mars. I must have spent 100s of hours pouring over Mars pictures from NASA and at google pro but don't remember seeing anything like this before.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 20 Mar 2018 01:48
by Amber G.
^^^ There are already a few.. for example this is - Ganges Chasma (or River Ganges)
(From: https://phys.org/news/2015-11-witness-early-mars.html
(The above picture is from ESA but if you look through my earlier posts - I remember posting picture of Ganges Chasma from one of the first photos taken by Mangalyaan)
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 24 Sep 2018 11:01
by Varoon Shekhar
Today(Sept 24/2018) is four years of Mangalyaan being in orbit. I hope they mark the event by posting some more photos. It's been many months since the last public ones. What an achievement to be orbiting Mars for 4 years, when the original lifespan was supposed to be 6 months!
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 24 Sep 2018 11:41
by ArjunPandit
[youtube]=https://www.youtube.com/watch?v=aIAq9UEPSWU[/youtube]
Such TFTA that it gives me goose bumps, came across as an ad on youtube, ended up watching a 23 min ad for the first time, in the meanwhile a young teammate came and she too got hooked had to watch it again. Didnt mind either
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 24 Sep 2018 14:58
by suryag
^^^^ Thanks AP ji, Can we put this video as a sticky. Extremely good acting by Prakash Belawadi(actually all others too) playing Radhakrishnan.
ArjunPandit wrote:[youtube]=https://www.youtube.com/watch?v=aIAq9UEPSWU[/youtube]
Such TFTA that it gives me goose bumps, came across as an ad on youtube, ended up watching a 23 min ad for the first time, in the meanwhile a young teammate came and she too got hooked had to watch it again. Didnt mind either
You have to put only {youtube]aIAq9UEPSWU [/youtube] the video id for embedding the youtube video
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 24 Sep 2018 16:14
by ArjunPandit
suryag wrote:^^^^ Thanks AP ji, Can we put this video as a sticky. Extremely good acting by Prakash Belawadi(actually all others too) playing Radhakrishnan.
ISRO statement on the fourth year of Mangalyaan in orbit.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 24 Sep 2018 22:42
by arshyam
ArjunPandit wrote:[youtube]=https://www.youtube.com/watch?v=aIAq9UEPSWU[/youtube]
Such TFTA that it gives me goose bumps, came across as an ad on youtube, ended up watching a 23 min ad for the first time, in the meanwhile a young teammate came and she too got hooked had to watch it again. Didnt mind either
This is a great find, Arjun-ji. Thanks for sharing.
I am sharing it with some groups that are involved in teaching rural kids.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 26 Sep 2018 14:09
by abhijitm
If Mangalyaan has enough fuel left then can we make it escape from mars like sling shot and travel towards Jupiter?
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 26 Sep 2018 14:29
by prasannasimha
The delta V to escape Martian orbit is too hogh. Gravity assist cannot be used after capture ! You can accelerate or decelerate using gravity assist but cannot escape once you are captured and are orbiting.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 27 Sep 2018 07:55
by Aarvee
Genuine question.
The video is a great initiative. But I thought even radio signals would take at least 4 minutes or so to reach mars from earth.
I was under the impression that the instructions for burn etc were per-programmed or at least sent much in advance. In the video, it looked like the operator would push a switch and the change happens in MOM. Is that just for fictionalisation?
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 27 Sep 2018 08:30
by SriKumar
At that time (and placement of Mars relative to earth in 2013) the time for one-way travel of signal was 8 minutes- quoting from memory here. There are some technically incorrect things...one guy talks about escape velocity. The craft did not reach escape velocity (it does not need to). Then he says the craft reached a velocity of 22 km/sec. I think it was about 32 km/sec of which 31 km/sec was from earth's speed of revolution; so the delta is about 1.0 km/sec. Initiative is good, but the drama seemed a bit over-done. The look-alike for Radhakrishnan was really good...it seemed like he played himself.
Added later: The velocity of the craft was about 32 km/sec after it left earth orbit; but it had to slow down as it reached Mars, and that was down to 22 km/sec. (The 8-minute figure- could not confirm it).
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 27 Sep 2018 21:37
by arshyam
Some of the details were indeed off, but it explains the complicated challenge in a relatively easy to understand way.
--- There are some headlines about "Mission is ending" or "Mangalyaan runs out of fuel" which are not quite accurate.. from what I know (and from my talk with people who ought to know)..
We will know soon and wait for ISRO's announcement - ISRO s working out the details of whether the spacecraft ran out of fuel and battery power, or whether communication was lost because of an automated manoeuver while moving out of a long eclipse changing the direction of the antenna. (I don't think it ran out of 'fuel' - very small fuel is needed -- most likely after coming out of eclipse - in a rollover maneuver it lost a fix - to communicate with earth --- we will know soon)
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 05 Oct 2022 10:10
by ramana
Looks like ISRO announced end of mission for this satellite.
Thanks Mangalyaan team!!!
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 05 Oct 2022 10:37
by Zynda
Many thanks to Mangalyaan team & ISRO for outstanding work. Hopefully they will get a chance to do more with Mangalyaan-2 sat...Launch is still 2+ years away...long time but hopefully will give team time tor realize their goals.
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 05 Oct 2022 23:21
by Amber G.
Yes end of the mission .. (that was expected/feared)..I was just amused to see *many* newspapers calling it 'ran out of fuel'. ..In all probability there may still be some fuel (IIRC 2Kg fuel was estimated to be there before the eclipse - per some people), enough to do few more course correcting but without communication control will be lost anyway. Even without fuel the orbit will last for years\)..Practically, speaking fuel means less, if the communication with earth is lost (or batteries ran out and (they can't face sunlight to charge etc)..
May be in a few years we will locate/pick up a radar blip on future mars missions or on powerful radio telescopes from earth...
It was also discussed that despite being designed for a life-span of six months as a technology demonstrator, the Mars Orbiter Mission has lived for about eight years in the Martian orbit with a gamut of significant scientific results on Mars as well as on the Solar corona, before losing communication with the ground station, as a result of a long eclipse in April 2022. During the national meet, ISRO deliberated that the propellant must have been exhausted, and therefore, the desired attitude pointing could not be achieved for sustained power generation. It was declared that the spacecraft is non-recoverable, and attained its end-of-life. The mission will be ever-regarded as a remarkable technological and scientific feat in the history of planetary exploration.
Rest in peace...!
----
(The reason is the inability of solar panels to be kept in the required attitude for power generation post-eclipse, however whether that was due to fuel depletion is not confirmed - as said, it matters little as if one can't recharge the batteries control is lost. Why I was getting amused at many newspaper headlines was their headlines was "fuel ran out". MOM needs fuel for attitude or orbit correction, does not need it to orbit)
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 06 Oct 2022 22:51
by Cyrano
What a stellar achievement by ISRO ! Take a bow !!
Re: Mangalyaan : ISRO's Mars Orbiter Mission
Posted: 07 Jan 2023 18:47
by SSSalvi
Late as usual.
( Actually I was regularly getting message that this is a scam site and can't be opened ... for last few years. )
It ( MOM ) really was a great achievement and we had one of the most fascinating discussions here.
