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Mangalyaan : ISRO's Mars Orbiter Mission

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sanjaykumar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby sanjaykumar » 11 Dec 2016 04:54

Having said that, I am sure there is more to it than this. This is too trivial an error to be wholly credible. Considerations of specificity are intrinsic to any test, it is not an afterthought.

Varoon Shekhar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Varoon Shekhar » 19 Jan 2017 23:01

http://economictimes.indiatimes.com/new ... 667570.cms

Realigned so that the spacecraft was not overly affected by the eclipse

Amber G.
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Amber G. » 25 Jan 2017 00:23

^^^ x post
Long Eclipse Avoidance Manoeuvres Performed Successfully on MOM Spacecraft
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.Image

Varoon Shekhar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Varoon Shekhar » 25 Jan 2017 02:51

^
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?

disha
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby disha » 25 Jan 2017 05:44

^ 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.

SriKumar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby SriKumar » 25 Jan 2017 06:55

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').

Varoon Shekhar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Varoon Shekhar » 25 Jan 2017 21:45

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

prasannasimha
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby prasannasimha » 25 Jan 2017 23:20

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.

Amber G.
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Amber G. » 26 Jan 2017 00:40

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.

First : From <this old issfd> -
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.

Varoon Shekhar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Varoon Shekhar » 24 Sep 2017 06:06

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!

ambati
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby ambati » 24 Sep 2017 18:00

any new result this year

Varoon Shekhar
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Varoon Shekhar » 25 Sep 2017 18:27

http://www.isro.gov.in/update/25-sep-20 ... ience-data

Data from 2014-2016. The last year's results will then come out next year and so on.

Amber G.
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby Amber G. » 26 Sep 2017 04:20

Let me repost my favorite -first snap after coming out of blackout..
Image

ArjunPandit
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Re: Mangalyaan : ISRO's Mars Orbiter Mission

Postby ArjunPandit » 26 Nov 2017 10:05

Alt balaji (online content from balaji telefilms) will make a series on mangalyaan. Not that i have very high hopes from them.
http://www.republicworld.com/s/13507/he ... e-based-on


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