Author Topic: ISRO Mars Orbiter Mission - Nov 2013 launch to September 2014 arrival - UPDATES  (Read 453878 times)

Offline AJA

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Tech demonstration mission has to demonstrate they can use, power and operate scientific instruments successfully, get data and process them.

They've already demonstrated a lot of that in the numerous Earth observation missions they've undertaken.

The raison d'ętre of this mission is to make an Indian platform seem as a viable option for the planetary sciences payloads of other agencies (a la NASA's M3 on Chandrayaan); and have this serve as a source of revenue. (Revenue doesn't have to be, and given NASA's operating regulations - will NOT be monetary compensation - but reciprocal rights to use assets of partners, without it costing ISRO).

Given this, "all" they need to do is to demonstrate they can get a platform to Mars, operate it around Mars, and characterise the operational environment within the spacecraft; before furnishing this information to their prospective payload instrument customers. The onus to make sure the instruments themselves can operate within those parameters is then left to the customer.

In that sense, an experimental ion engine (they do have one in the works IIRC) would be as good, if not a better (as I said in my previous comment) 'payload'. Plus, I wasn't suggesting removal of ALL scientific payloads, simply the ones that are going to gather similar data to what's already been gathered. (Even MAVEN isn't carrying a camera as such... if you exclude the IUVS)

These links might help

Thanks, but they don't have numbers on delta-v required for MOI, and how that delta-v changes over time. Oh well, back to googling for me :)
« Last Edit: 09/13/2014 01:37 PM by AJA »

Offline vyoma

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...an experimental ion engine (they do have one in the works IIRC)...
ISRO had used ion thrusters in GSAT-4 in 2010 (but satellite didn't make it to orbit due to LV issues):
http://forum.nasaspaceflight.com/index.php?topic=33770.0
« Last Edit: 09/13/2014 02:02 PM by vyoma »

Offline vineethgk

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... why did they include something like a Mars Colour Camera, instead of an experimental ion engine (in addition to the LAM)? The scientific community already has a million images of Mars... taken from much closer than Mangalyaan's nominal peri-areion. They've got full-disk images too - and if AIUI, all this data is already in the public domain. Sure, more images always helps; but the tradeoff is having a system which enhances the chances of mission success, while validating a new indigenous implementation of an alternative propulsion technology.

I see your point of increasing chances of the mission's success by sacrificing one or more of the payloads and instead bundling an alternate (albeit untested) propulsion unit. But I wonder whether the MCC should be the one that needs to be axed for it.

ISRO officially says that snaps from the Mars Color Camera would provide the context for other scientific payloads. But for me personally, a much greater justification for having a Color Camera onboard MOM (which weighs lowest among its 5 instruments at 1.27 kg) is that this mission needs to be seen not just as a technology demonstrator or as an advertisement of ISRO's capabilities in the global arena, but as a domestic PR effort as well. Images are something that a common man can relate to more easily, as against heady stuff like Methane measurement, Lyman-alpha emissions etc that appeal only to the core scientific community. Imagine an average Indian reading the newspaper on Sep 25 and seeing the leading news as something like "Indian spacecraft enters Mars orbit, starts sending scientific data" accompanied by only a few graphical plots to illustrate. Chances are, that he may not understand what the ruckus is all about and would just gloss over it. But imagine if the report was titled "Indian spacecraft enters Mars orbit, sends spectacular images of the planet" bundled with a half page color snap of Mars taken by the orbiter. It may not mean much to the wider scientific community, but wouldn't the impact on an average reader in India be more pronounced (to put it mildly)? Spacecrafts from other countries may have taken a lot of better photos of the planet, but what feels more special to us than a snap taken by a spacecraft built and launched by our effort?  :)

On a more general note, an effective domestic PR effort from ISRO, in ways that more number of people on the street can relate to, would have multiple benefits. First, it would build more domestic support for ISRO  enabling the government to allocate more funds to them without fear of getting bashed by the public. Second, it would drive more talented youth to strive to take up career with such organizations here, or maybe embark on a career in the core sciences boldly. Third, on a longer term, it would also drive up the scientific temperament of the population, something the country badly needs.

I often speak passionately about the Mars mission to my colleagues in the IT firm where I work, trying to explain to them in the best of my knowledge the enormous complexities involved in merely launching something to a precise orbit, let alone managing an interplanetary space flight. But they still seem to think it is no big deal (as if it is only as difficult as building a crappy web application), and many even say their taxpayer money are getting wasted on some 'overhyped skyrockets' !! Alas, I wish they knew better!  :(
« Last Edit: 09/13/2014 05:43 PM by vineethgk »

Offline hop

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In that sense, an experimental ion engine (they do have one in the works IIRC) would be as good, if not a better (as I said in my previous comment) 'payload'.
MOM was built on an very compressed timeline for a planetary mission. Adding experimental technologies is not usually a good idea in this situation. If they get into orbit and return some data it will be tremendous success.

It's not really clear an ion engine would benefit the mission either. MOM has relatively little power available and no mass margin to add more.

Offline Mader Levap

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Tech demonstration mission has to demonstrate they can use, power and operate scientific instruments successfully, get data and process them.
They've already demonstrated a lot of that in the numerous Earth observation missions they've undertaken.
Not really. Data gathering and transmission from another planet is sufficiently different.

In that sense, an experimental ion engine (they do have one in the works IIRC) would be as good, if not a better (as I said in my previous comment) 'payload'.
Not realistic. In fact, trying to force newest and untested techologies into mission not specifically dedicated to test them is good way to fail project. So this is really bad idea.
Be successful.  Then tell the haters to (BLEEP) off. - deruch
...and if you have failure, tell it anyway.

Offline sdsds

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In comparing Mars Orbit Insertion maneuvers, it looks like MOM and Maven are taking slightly different approaches. AIUI, Maven will be capturing into an orbit with a 590 km periapsis; MOM into an orbit with a 365 km periapsis. Each needs to get well below escape speed for that altitude: for Maven that's 4640 m/s; for MOM it is 4780 m/s.

So the task for MOM looks easier. I wonder why didn't Maven choose to insert into a capture orbit with a lower periapsis, or put differently what enables MOM to do so when Maven (apparently) can't? I'm speculating it's because the MOM engine is higher thrust and can thus impart the needed impulse quickly enough, whereas Maven's monoprop thruster couldn't. Or is there another reason?
-- sdsds --

Offline vyoma

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Superb press kit on sequence of events so far, MOI plan, LAM propulsion system:
http://www.isro.org/mars/pdf/press%20briefing%20on%20MOI.pdf

Simulation video:
http://www.isro.org/mars/moi-video.aspx
« Last Edit: 09/15/2014 02:03 PM by vyoma »

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 antriksh

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« Last Edit: 09/15/2014 02:17 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 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 antriksh

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Quote
1) ISRO engineers will start the final orbit insertion operation at 4.17 am on September 24 morning when the Mars Orbiter will switch to the Medium Gain Antenna for communications.

2) At 6.56 am, the Orbiter will be rotated in a forward direction.

3) At 7.12, a solar eclipse starts and two minutes later the thrusters will be used to get the Orbiter aimed in the right attitude.

4) At 7.17 am, the liquid engine burn will start and it will go on for 1454 seconds burning 249.5 kg of propellant to decelerate the spacecraft by 1098.7 Meters/second.

5) Around the same time, telemetry machines would be switched off as the Orbiter will lose communications with ground control being on the other side of the planet.

6) News of the confirmation that burn has started will reach ground control only after 12.5 minutes at 7.30 am.

7) The communication gap will end at 7.45 am and telemetry and doppler tracking will resume at 7.47 if all goes according to plan.
« Last Edit: 09/16/2014 01:41 AM 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 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 vineethgk

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http://www.thehindu.com/sci-tech/science/indias-mars-mission-to-enter-mars-orbit-on-september-24/article6413143.ece?homepage=true

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In the run-up to the D-day, the mission scientists will do course (trajectory) correction on September 22.
“The course correction has been postponed to September 22 from Sunday (September 14) to conserve the precious liquid fuel weighing (852 kg) and ensure the orbital insertion takes place when the spacecraft is closer to Mars for smooth transition from the sun’s orbit,” Mr. Rao said.

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“The liquid apogee motor (LAM) or fuel engine at the bottom of the spacecraft will be fired on September 22 for four seconds to enter the Martian sphere of influence and the course correction will consume about 500gm of fuel,” Mr. Rao said.

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The speed of the spacecraft will also be reduced to 2.14 metre per second from 22.2 km per second for enabling smooth transition into the Martian orbit from the sun’s orbit Sep 24.
  Must be a typo - maybe they meant the 2.14 m/s delta-v?

 
Quote
At 6.56 a.m., the spacecraft will be rotated towards Mars and five minutes later when sunlight is not falling on the Martian surface causing eclipse, the thrusters beneath the engine will give the Orbiter altitude control.

“The liquid engine will start firing at 7.17 a.m. and at 7.21 a.m., Mars occult begins. A minute later at 7.22 a.m., telemetry (radio signals) will be off or out of receiving radars on the earth,” Mr. Rao pointed out.

Scientists at the space agency’s deep space network at Byalalu, about 40 km from Bangalore, NASA’s Earth station at Goldstone on the U.S. west coast, the ESA’s Earth station at Madrid will confirm the insertion into the Martian orbit 24 minutes later at 7.54 a.m.

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The spacecraft, with five scientific instruments, will be placed in an elliptical orbit, with the nearest distance from the Martian surface being 423 km and the furthest 80,000 km, to rotate around it in a duration equivalent to 3.2 earth days.

Has the periapsis been increased from the original plan of around 300km? Or maybe this the initial periapsis at injection which will be reduced in a subsequent burn?

Offline Steven Pietrobon

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According to the press briefing, the delta-V is 1098.7 m/s.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline vineethgk

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According to the press briefing, the delta-V is 1098.7 m/s.

Yes, and the predicted delta-v for the 4 second test firing on 22nd is mentioned as 2.142 m/s.

Are there any optimistic guesses that can be made now as to what the achievable orbit could be if the LAM test were to fail and only the eight 22N thrusters are available for firing on 24th (which ISRO mentions as Plan B)?
« Last Edit: 09/16/2014 09:11 AM by vineethgk »

Offline seshagirib

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As per the propulsion diagram ( Page:8 ) in the press briefing document, both the LAM and the attitude thrusters use the same propellant and oxidizer.

How come there is so much concern about the restarting and operation performance of LAM, but no apparent concerns on the thrusters operation?

Offline vineethgk

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As per the propulsion diagram ( Page:8 ) in the press briefing document, both the LAM and the attitude thrusters use the same propellant and oxidizer.

How come there is so much concern about the restarting and operation performance of LAM, but no apparent concerns on the thrusters operation?

Maybe the greater amount of propellant flow and longer duration of thrust in the Main engine increases chances of clogging and corrosion in its fuel lines and valves compared to the smaller thrusters? Or some difference in construction between the two? Maybe someone knowledgeable on these things can shed light on it.

Apologies if this has been shared before, but I found a link with details of the 440N and 22N thrusters used in ISRO satellites.

http://articles.adsabs.harvard.edu//full/1999ESASP.430..579S/0000579.000.html


« Last Edit: 09/16/2014 12:34 PM by vineethgk »

Offline hop

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How come there is so much concern about the restarting and operation performance of LAM, but no apparent concerns on the thrusters operation?
My guess: The smaller thrusters are designed to operate for many years, and have done so on previous missions. They have also been used for the TCMs during the flight. The LAM was originally designed for a few firings immediately after launch, and doesn't have the same kind of record for long term use.

That said, the fact ISRO decided to do a test firing so late in the process might indicate some more specific concerns were identified post launch. If it were a NASA mission, I would expect a test like this to be planned out before launch, unless it was driven by issues identified later. That logic might not apply to MOM though, given that it's ISRO's first deep space mission and was developed on such a tight schedule.

How come there is so much concern about the restarting and operation performance of LAM, but no apparent concerns on the thrusters operation?
My guess: The smaller thrusters are designed to operate for many years, and have done so on previous missions. They have also been used for the TCMs during the flight. The LAM was originally designed for a few firings immediately after launch, and doesn't have the same kind of record for long term use.

That said, the fact ISRO decided to do a test firing so late in the process might indicate some more specific concerns were identified post launch. If it were a NASA mission, I would expect a test like this to be planned out before launch, unless it was driven by issues identified later. That logic might not apply to MOM though, given that it's ISRO's first deep space mission and was developed on such a tight schedule.

I think it's more of them needing a TCM anyway (remember that a planned TCM was deemed unnecessary a few months ago) and deciding to use it as a test firing of LAM. The delta V requirement of this TCM is low enough to be easily accomplished by the thrusters but high enough to fire the LAM for a few seconds and make sure all the fuel lines are open. It is too late for them to plan and execute a contingency in case of LAM failure, MOI cannot be achieved by the thrusters alone.

Offline sanman

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Indian PM interested in witnessing Mars Orbital Insertion:

http://www.newindianexpress.com/states/karnataka/Modi-Keen-on-Witnessing-Mars-Moment/2014/09/17/article2434963.ece

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BANGALORE: Prime Minister Narendra Modi has expressed interest in witnessing the entry of  Mars Orbiter Mission into the red planet around 7.30 am on September 24.

Modi would arrive in Karnataka on September 23 on his maiden visit, after taking over the country’s top job.

The Prime Minister is likely to visit ISRO Telemetry, Tracking and Command Network (ISTRAC) near Peenya here to witness the historic event and congratulate the ISRO team. The BJP state leadership has planned a grand reception for Modi on his arrival at the HAL airport in the evening.  Former Deputy Chief Minister R Ashok and others inspected the airport on Tuesday to select a suitable spot for erecting a shamiana for the purpose.

BJP state president Prahlad Joshi, Union Minister H N Ananth Kumar and others would felicitate Modi, Subbanna of the BJP Bangalore city unit told Express.

Modi would stay at Raj Bhavan for the night and leave for Tumkur the next morning. He is keen on visiting ISTRAC before leaving for Tumkur.

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