Author Topic: ISRO Mars Orbiter Mission - Nov 2013 launch to September 2014 arrival - UPDATES  (Read 452576 times)

Offline AJA

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Official ISRO update from the Mangalyaan mission webpage


Quote
Date: 12/06/2014
   
  • The second Trajectory Correction Manoeuvre (TCM-2) of India's Mars Orbiter Spacecraft was successfully performed on June 11, 2014 at 1630 hrs IST. TCM-2 was performed by firing the spacecraft’s 22 Newton thrusters for a duration of 16 seconds.
  • At present, the radio distance between the Spacecraft and the Earth is 102 million km. A radio signal from the Earth to the Spacecraft now takes about 340 seconds. The spacecraft so far has traveled a distance of 466 million km as part of its total Journey of 680 million km.
  • ISRO is continuously monitoring Mars Orbiter Spacecraft using Indian Deep Space Network (IDSN). The spacecraft and its five scientific instruments are in good health.

  • So, RCS was used, rather than the Liquid Apogee Motor. The delta-V was small (1.577 m/s), so I guess there's nothing to be read into it.

    Still, I think this will probably the longest period between LAM burns... when it does the orbital insertion. Unless an INSAT adjusted its orbit fairly drastically late in its life, or reboosted. Anyone aware of such an occurrence?
    « Last Edit: 06/18/2014 02:34 PM by AJA »

    Offline vyoma

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    Still, I think this will probably the longest period between LAM burns... when it does the orbital insertion. Unless an INSAT adjusted its orbit fairly drastically late in its life, or reboosted. Anyone aware of such an occurrence?

    Even I'm curious to know about this. I couldn't find any instance of LAM restart after such a long gap. However, this article has some info about LAM qualification for MOM (requires free registration):
    http://www.frontline.in/cover-story/mission-to-mars/article5280848.ece

    Here are some interesting snippets:
    Quote
    The final Mars Orbit Injection (MOI) is achieved by a braking or de-boost manoeuvre of about 1.1 km (a negative Δv) at the periapsis (closest approach to Mars) of the hyperbolic MTT. This, in fact, is the largest incremental (albeit negative) velocity, which means the MOI will demand the longest retro firing of LAM and it will have to deliver after lying idle for 300 days. Together, with the incremental velocity of 1.5 km/s given up to trans-Mars injection, the magnitude of the cumulative incremental velocity required of LAM is thus 2.6 km/s. The spacecraft will enter the Martian orbit in September 2014.

    Quote
    The LAM that will be used in this mission, both for orbit raising and MOI, is the same 440 Newton thruster that is used in geostationary satellite launches by ISRO. The first operation of orbit raisings is limited to the first one week. But MOI is only after 300 plus days of MTT. Once the valves get wetted by the propellant, they can swell a little bit and the performance will come down. They may also begin to leak. So the strategy that has been adopted is to close this path after orbit raisings, isolate the engine by operating pyro valves and open additional flow lines and valves when restarting the engine 10 months later to take care of the problem. The engine has been tested for its performance for a given number of days after use.

    Quote
    “In Chandrayaan-1 the engine was qualified for 30 days. Now we are talking of 300 days,” pointed out Radhakrishnan. “The performance deterioration in propulsion efficiency, which means specific impulse, is about 2 per cent. So we know it a priori. When you finally want to calculate how much the engine should fire to impart a given retro boost to capture a Martian orbit, this information is important but not very crucial at the same time because it is done in the closed loop mode. It will be looking at the accelerometers and then adjusting automatically. Also, the trans-Martian injection being very complex, you may miss this capture. We have kept fuel for one more try,” he added

    Offline AJA

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    Not having pored over INSAT operational burns, I think the closest they've come so far is Chandrayaan. I went and checked the dates/durations of the LAM burns on that mission (Wikipedia).

    Starting on 23rd October 2008, the LAM was fired (for Earth orbit raising) a total of 5 times with intervening gaps of 2, 1, 3, and 6 days. The LOI burn followed (6th LAM burn) on 8th November 2008 (a gap of 4 days after the TLI burn). Subsequently, there were 4 burns to circularise tighten the orbit - on 9th, 10th, 11th, and 12th of November. (Cumulative burn time of 4711s, prior to the 12th November burn)

    However, I'd forgotten that Chandrayaan raised its orbit on 19th May 2009 (because of the temperature problem) - from 100 km to 200 km. That would've been the 11th LAM burn. This puts the biggest gap between successive, successful LAM burns at ~188 days.

    Here's Mangalyan for comparison (Wikipedia).

    Starting on 6th November, there have been a total of 7 LAM burns thus far, including TMI - with the gaps between subsequent burns being 1, 1, 2 (incomplete 4th burn - because ISRO were doing some redundancy testing. Cumulative burn time prior to onset of incomplete burn: 1693.6s. Chandrayaan passed this mark with its 2nd burn itself.), 1, 4 and 15 days respectively. Cumulative burn time thus far = 3569.79s.

    The TMI was completed on 1st December 2013 (01:12 IST), and a nominal MOI is expected on 24th September 2014 (IST). That's a gap of ~297 days.

    So yeah, they'd need to beat the current record by 110 days (~160%).

    Having said that, even without the alternative flow lines, the hardware isn't EXACTLY identical. The engine may be, but the tanks are either larger, or more numerous - which imply either different fuel pressures after the same del-V, and different temperatures, OR more valves/flow pressure regulators. And obviously, the external environment (including other parts of the S/C other than the propulsion system) isn't the same.
    « Last Edit: 06/20/2014 04:10 PM by AJA »

    Offline AJA

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    Offline plutogno

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    Offline antriksh

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    India plans another Mars mission in 2017-20

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    follow-on" mission to the Red Planet between 2017 and 2020 having a lot of scientific content. the final decision will depend upon the success of the Mars Orbiter Mission (MOM) orbit insertion on September 24, 2014

    http://timesofindia.indiatimes.com/india/India-plans-another-Mars-mission-in-2017-20/articleshow/38565995.cms
    Nasadiya Sukta:
    Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

    From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

    Offline Star One

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    India plans another Mars mission in 2017-20

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    follow-on" mission to the Red Planet between 2017 and 2020 having a lot of scientific content. the final decision will depend upon the success of the Mars Orbiter Mission (MOM) orbit insertion on September 24, 2014

    http://timesofindia.indiatimes.com/india/India-plans-another-Mars-mission-in-2017-20/articleshow/38565995.cms

    Excellent news, you have to admire their ambition on this.

    Offline antriksh

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    Nasadiya Sukta:
    Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

    From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

    Offline vyoma

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    Third trajectory correction manoeuvre planned in August deemed not necessary.

    Quote
    ISRO on Thursday said, "The mission officials have just ruled out the need for a trajectory correction manoeuvre, originally planned for August. This means MOM needs only three out of four TCMs originally planned for the entire heliocentric journey."

    http://www.deccanchronicle.com/140801/nation-current-affairs/article/mission-mars-schedule

    Offline vyoma

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    http://www.financialexpress.com/news/in-final-lap-isros-mars-spacecraft-to-burn-240-kgsfuel-to-slowdown-enter-martian-orbit/1275814/0

    Quote
    "It is currently about 163 million kilometers away from Mars. It is travelling at a speed of 1.2 million kilometers per day. It is on schedule and on target. Originally we were planning to have a corrective manoeuvre on August 19. But in the current situation, we don't think it is necessary. So the next (trajectory) correction is scheduled for September 14 and on September 24, the orbiter is supposed to reach Mars and perform the manoeuvre to orbit the red planet,"

    Quote
    "We have 290 kilograms of fuel left, and we will require about 240 kilograms for the manoeuvre to enter the Mars orbit. The process will involve reducing the velocity of the spacecraft and allowing it to get captured by Mars' (gravity),"

    Quote
    he said adding that all the commands will be fed in to the spacecraft three days in advance (before the manoeuvre on September 24) and the manoeuvre is expected to happen using the autonomous features of the spacecraft at 7:30 am on September 24.




    Offline antriksh

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    Quote
    After the spacecraft is captured in the Mars' orbit, we will encounter the Siding Spring comet that will engulf Mars in October

    Quote
    The MOM will be using the instruments onboard to observe the Siding Spring's passage and its effects on the Martian atmosphere which is much thinner that compared to Earth.

    ISRO's Mangalyaan to encounter Siding Spring comet in October
    Nasadiya Sukta:
    Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

    From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

    Offline ss1_3

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    Offline seshagirib

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    Will ISRO test fire the LAM ( for a short duration ) prior to the actual MOI burn to check out and calibrate the LAM?

    Offline vyoma

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    Will ISRO test fire the LAM ( for a short duration ) prior to the actual MOI burn to check out and calibrate the LAM?

    These posts have some info on LAM firing after 300 days:
    http://forum.nasaspaceflight.com/index.php?topic=29440.msg1216254#msg1216254
    http://forum.nasaspaceflight.com/index.php?topic=29440.msg1216393#msg1216393

    But, am not sure if ISRO will be test firing LAM.

    Offline antriksh

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    Will ISRO test fire the LAM ( for a short duration ) prior to the actual MOI burn to check out and calibrate the LAM?

    I guess not. The original plan was to use all the redundant lines for the fuel  during MOI, but a similar test in the earth orbit didnt work. Apparently, each line works individually but not in parallel. My guess, they will program it to open other line if one fails  to produce required deceleration during MOI. 

    BTW, MOI will happen behind mars (just like chandrayaan 1), so any guesses how long we will have to wait for a confirmation?
    Nasadiya Sukta:
    Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

    From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

    Offline vyoma

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    http://timesofindia.com/india/Mars-orbiter-mission-spacecraft-readies-to-hide-behind-Red-Planet/articleshow/40557929.cms

    Quote
    The spacecraft is travelling at a speed of 22km/second. The challenge before Isro would be to reduce this drastically to 1.6km/second, so that the rules of gravity around Mars are employable and the spacecraft is sucked into the desired orbit.

    To achieve this, the space agency must fire its LAM engine, which would have remained idle for 299 days by September 24. Not only will the engine have to be fired but it has to be done after changing the orientation completely.

    "Right now MOM is travelling in one direction, if we just fire the engine, it will only add to the velocity. So we will have to re-orient it to look the opposite direction and then fire the engine. What this does is it will push the spacecraft in the opposite direction and thereby reduce velocity," a senior scientist said.

    Offline seshagirib

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    Will ISRO test fire the LAM ( for a short duration ) prior to the actual MOI burn to check out and calibrate the LAM?

    I guess not. The original plan was to use all the redundant lines for the fuel  during MOI, but a similar test in the earth orbit didnt work. Apparently, each line works individually but not in parallel. My guess, they will program it to open other line if one fails  to produce required deceleration during MOI. 

    BTW, MOI will happen behind mars (just like chandrayaan 1), so any guesses how long we will have to wait for a confirmation?

    Maybe ( just guessing ) - if the LAM has issues in both the modes ( primary lines and redundant lines ) the MOI software could try to put the MOM in some kind of orbit around Mars using the attitude thrusters. This will buy time to try and fix the LAM issues.

    Offline antriksh

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    Will ISRO test fire the LAM ( for a short duration ) prior to the actual MOI burn to check out and calibrate the LAM?

    I guess not. The original plan was to use all the redundant lines for the fuel  during MOI, but a similar test in the earth orbit didnt work. Apparently, each line works individually but not in parallel. My guess, they will program it to open other line if one fails  to produce required deceleration during MOI. 

    BTW, MOI will happen behind mars (just like chandrayaan 1), so any guesses how long we will have to wait for a confirmation?

    Maybe ( just guessing ) - if the LAM has issues in both the modes ( primary lines and redundant lines ) the MOI software could try to put the MOM in some kind of orbit around Mars using the attitude thrusters. This will buy time to try and fix the LAM issues.

    Actually that is what happened when the parallel mode failed during the test in earth orbit. Thrusters will come into action but my guess is that it wont be sufficient to reduce the velocity of the spacecraft to required 1.6 km/s to be captured by Mars gravity.

    BTW

    Quote
    "On Sept 24, the manoeuvring of the spacecraft will begin around 7.30 a.m. The spacecraft's speed will be reduced from the current speed so that the Mars Orbiter enters the Martian orbit. Whether the spacecraft has entered the Martian orbit or not will be known around 8.30 or 9 a.m."

    http://www.business-standard.com/article/news-ians/mars-orbiter-to-enter-red-planet-s-orbit-sept-24-114082300454_1.html
    « Last Edit: 08/23/2014 02:03 PM by antriksh »
    Nasadiya Sukta:
    Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

    From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

    Offline AJA

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    Will ISRO test fire the LAM ( for a short duration ) prior to the actual MOI burn to check out and calibrate the LAM?

    I guess not. The original plan was to use all the redundant lines for the fuel  during MOI, but a similar test in the earth orbit didnt work.

    Are we sure we know what it is EXACTLY that they tested?

    Here are some interesting snippets:
    Quote
    The final Mars Orbit Injection (MOI) is achieved by a braking or de-boost manoeuvre of about 1.1 km (sic: it should be 1.1 km/s) (a negative Δv) at the periapsis (closest approach to Mars) of the hyperbolic MTT. This, in fact, is the largest incremental (albeit negative) velocity, which means the MOI will demand the longest retro firing of LAM and it will have to deliver after lying idle for 300 days.

    Quote
    Once the valves get wetted by the propellant, they can swell a little bit and the performance will come down. They may also begin to leak. So the strategy that has been adopted is to close this path after orbit raisings, isolate the engine by operating pyro valves and open additional flow lines and valves when restarting the engine 10 months later to take care of the problem. The engine has been tested for its performance for a given number of days after use.


    ^So why would they test the second set of lines? The second set of lines are not so much redundant, as much as required. If they wet them with propellant - in Earth orbit itself - it'd destroy the entire point of having a second set in the first place. Also, if they used the pyro valves to isolate the first flow path... then they're now down to only one set of fuel lines. i.e. there's no redundancy.

    Plus, the fact that the MOI burn - though autonomous - is being executed as one big burn, rather than being split over the hyperbolic approach trajectory - makes me think that they don't want to close and open the valve repeatedly... and risk it getting jammed.

    Can someone (else) ask them on Facebook/Twitter?
    « Last Edit: 08/30/2014 05:25 PM by AJA »

    Offline seshagirib

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    As the s/c approaches Mars will it focus the camera and other instruments on the planet before MOI burn to (e/i)nsure some science return from the mission ?
    « Last Edit: 08/31/2014 04:51 PM by seshagirib »

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