Mangalyaan: ISRO's Mars Orbiter Mission

[SaiK]

del

[SaiK]

del.

dunno, how this multiple posts happen

[SaiK]

hey that is NSFW!

[Victor]

Another issue is whether they have to alter their orbit to avoid particles in the comet tail that could damage the probes.

This is from Lakdawala's blog, written in August, before MAVEN and MOM reached Mars:
October encounter with comet Siding Spring

We think they're probably safe, but out of an abundance of caution, all three orbiters currently at Mars are shifting the timing of their orbits just slightly so that they will wind up on the far side of Mars from the comet when Mars' path through the tail reaches the region of highest dust density, about 100 minutes after the closest approach of the comet. The two orbiters on their way to Mars will also perform adjustments to keep on the safe side at the right time.

Seems to indicate that MOM also plans to shield itself.

[Vayutuvan]

http://www.nasa.gov/topics/technology/f ... gxnlt.html

Bade: That is a good link. Thanks. I thought pulsars would be the preferred choice between Quasars and Pulsars. Looks like they might be but are also need more sophisticated measuring equipment.

Could you please throw light (no pun intended ) two points?

1. How hard is it to setup experiment for Methane Sink tumbler using SiO2 as given in a paper referred to in that summary article you posted from PRL? The original paper by Jensen et al. would give the detailed setup I presume. Am I way off in thinking that it would be accessible to all IITs, many NITS and old engg. colleges? Would it be possible to catalog all such experiments that can be done at college level? They would make excellent projects for National Labs/Engg. college interactions and as teaching methods.

2. What are these "specially developed algorithms" NASA publication talks about? Can parts of these be developed by IITs etc.? Again will be very good teaching tool for UG research project me thinks. I could be way off though.

[Bade]

matrimc, if there is will on part of the institutes they should be able to replicate similar experiments. If these colleges are co-located with PRL, A'bad or SPL Tvm then they can even draw upon expertise and facilities that reside in those places. As always the devil is in the details, so nothing is easy. IIT-M BTech/MSc students I know from various newsletters, are putting together a decent payload for launch with ISRO's help. So it is happening already in a few places.

This will be an interesting detailed read too in that context of space navigation.
http://smad.com/wp-content/uploads/AAS-08-054-XNAV.pdf

[Vayutuvan]

For PRL, IIT Gandhinagar will be almost hand in the glove. The kind of academic-national labs interaction that takes place in the US is very high. If some programs of that nature were to be initiated in india too, tht a low cost alternative to having sophisticated labs and equipment in Engg. colleges. When I was in UG, we were very lucky to have professors who worked in Defense Labs or had excellent networking with them. We would have weekend lectures and seminars. Just one or two at the top who are motivated researchers and are also interested in applications would do wonders for developing intuition about practice and hurdles faced in real life. That too at lower cost. There is always the negative side, i.e. insufficiently motivated students who do not do the basic homework and wil become a drag on the researchers' time. I guess the details have to come in as uniform policy from the top.

[V_Raman]

Saw this on BBC and one of the company emps makes the statement "no country has become a developed country without a good space/aerospace industry". So much for all the mangalyaan baiters.

http://www.bbc.com/news/business-29379159

The plane itself is very interesting for India.

[Amber G.]

Victor - These "ducking for cover" make nice stories and headlines. Yes, all NASA's crafts are taking cover as the stories say, but no one knows the exact (or even approx ) flux of the particles of comet's tail. Just for perspective - (Even with the best telescopes on earth, the visible coma of the comet is something like 20,000 Km - and closest the nucleus will be at about 130,000 Km from Mars )

- SS is not hitting Mars, at its nearest, will pass through at 130,000 Km from Mars(about 1/3 Earth-Moon distance).
- The particles, in the tail, will be travelling about 46Km/Sec wrt to MOM (or mars).. very fast, so even a small (say 1 mm in diameter) dust particle can cause a lot of damage.
- As days pass, more data will come in, but at present best estimates are that such for a 10 sq meter area (like MOM) the chances are 1 in 300,000 or so, that any 1 particle (size above) will hit MoM
- Also, if you "duck for cover" (whatever that means, specially in MoM's case), you may miss a nice show of Mars' aurora..

BTW, SS's perigee (closet it will come to Sun) will occur on October 25th. Then it will head back to outer solar system. No one knows the time period, or if the comet will ever come back to visit the inner solar system, but if it does, it will not do so for about a million years.

[Amber G.]

This is from Lakdawala's blog, written in August, before MAVEN and MOM reached Mars:
October encounter with comet Siding Spring

...Seems to indicate that MOM also plans to shield itself.

May be of interest, from the same blog but more recent articles.. (essentially echoing what I posted)..
(sept 9) Why isn't Siding Spring going to sandblast Mars?

...The really good news is that, because the risks are fairly minimal, the spacecraft teams are planning to study the comet and its effects on Mars...

And more recent blog (from the same place):

(Sept 15): Comet Siding Spring Mars encounter:

...By the middle of this summer, published estimates (based on new images and additional modelling) were indicating a flux of around 10^-6 particles per square meter, .... It's starting to look like our comet C/2013 A1/Siding Spring will manifest itself as a more friendly passer-by than initially thought and that it won't be hurling clouds of large particles at unthinkable speeds towards Mars and its human-made satellites..

(conclusion very similar to what I posted)

And the most recent:
Oct 3 -Preparing for A-MAVEN Science

We’ve established that any dust from Comet Siding Spring that reaches Mars’ atmosphere will sparse in number. Chances are that Mars will encounter no more dust than it does on any other given day of the year.

(Lot of good information, so please read in full, if interested)

[SaiK]

from bade saab's bade bade link: (awesome doc)

The baseline XNAV approach uses observations of the X-ray emissions of highly stable, rotation powered, millisecond pulsars as a kind of natural celestial beacon. Accurate pulse time-of-arrival estimates from multiple non-coplanar sources allow simultaneous determination of both position and velocity autonomously anywhere in the solar system. Accurate time can be maintained on a spacecraft through the use of onboard atomic clocks or the monitoring of the long-term stability of several well-characterized pulsars. In addition, brighter, less stable X-ray sources may have utility as well, particularly in applications that require only relative navigation information.

- The system is passive, requiring only infrequent pulsar ephemeris updates, and can operate in an autonomous mode, independent of Global Positioning System (GPS) and DSN systems.
- It can provide measurements that are in a direction perpendicular to the line of sight (LOS) from Earth to the
spacecraft.
- The detectors are highly resistant to blinding or contaminating events. Detectors used within the XNAV system are intrinsically radiation hard due to their design for recording photon events.

read the math part determining the error, perhaps matrimc/amberji could explain that better.
read the conclusion that it can be used with DSN.

thanks for the link bade.

[SriKumar]

(For me, it is amazing that perhaps NGC 4438, which is 50 million light-years away, helped pinpoint MOM to an accuracy of about 1 meter from antennas placed on Earth.. and it's speed within 3 meters per hour - 1 mm/sec)... think about that folks.)

The accuracy above is borderline unbelievable. For a craft that's traveling roughly 23 km/sec (=Mars velocity around sun), the accuracy in measurement is as refined as 1mm/sec (~ 6th decimal point). How are they able to verify this? Do they use 2 different methods of estimating velocity and the answers are within 1mm/sec of each other? Similarly, the nano-radian accuracy is also amazing. I mean, the instruments (i.e. the onboard camera) and the craft on which they are riding will all be subject to vibration (parts may move/rotate more than a nano-radian), expansion/contraction due to cold of space/effect of sunlight- they will warp/change shape even if minutely, how much can onboard instrumentation be trusted to capture this level of accuracy.

And one small detail to complete the GPS discussion: what is the accuracy of the clock in a GPS receiver- would that be 10-7 sec (i.e. voltage-based oscillators) per Mort's post?

[member_28108]

Accuracy of a GPS receiver is different from the GPS clock.

http://gpsinformation.net/main/gpstime.htm

[Amber G.]

(For me, it is amazing that perhaps NGC 4438, which is 50 million light-years away, helped pinpoint MOM to an accuracy of about 1 meter from antennas placed on Earth.. and it's speed within 3 meters per hour - 1 mm/sec)... think about that folks.)

The accuracy above is borderline unbelievable. For a craft that's traveling roughly 23 km/sec (=Mars velocity around sun), the accuracy in measurement is as refined as 1mm/sec (~ 6th decimal point). How are they able to verify this? Do they use 2 different methods of estimating velocity and the answers are within 1mm/sec of each other? Similarly, the nano-radian accuracy is also amazing. I mean, the instruments (i.e. the onboard camera) and the craft on which they are riding will all be subject to vibration (parts may move/rotate more than a nano-radian), expansion/contraction due to cold of space/effect of sunlight- they will warp/change shape even if minutely, how much can onboard instrumentation be trusted to capture this level of accuracy.

And one small detail to complete the GPS discussion: what is the accuracy of the clock in a GPS receiver- would that be 10-7 sec (i.e. voltage-based oscillators) per Mort's post?

Good question(s). Few comments...

First - Let me give one reference (but others can find out more good sources) which talks about all issues your raised, and gives a detailed technical account.

(Report Concerning Space Data System Standards - Technical characteristics and performance)

http://public.ccsds.org/publications/ar ... 00x1g1.pdf

Check out chapter 4, where all different uncertainties/noise is discussed..including quasar's contribution etc.

(What I said, though not too detailed or "accurate" in precise mathematical sense, but true in general sense - sort of summary or main points. The values (1mm/sec or 1 nano-radians were "limits" of achievable accuracy - not the actual values needed/achieved )

Now few comments -
- There are about 200,000 standard quasars listed in typical standard "guide books" with their accurate position (better than 1 nano-radian) for reference.

-The next "update" to the ICRF will be done in space. (The European Space Agency satellite called Gaia (with reference to about a half-million quasars). Gaia uses an optical telescope, but because it is above the atmosphere, the satellite will be able to clearly see these quasars and precisely locate them in the sky and expects to have enough observations by 2018 to produce the next-generation ICRF (sub uas resolution) (For example see: http://syrte.obspm.fr/journees2013/powe ... _jsr13.pdf


- Main benefit of quasar readings is to compensate errors/uncertainty caused by waves travelling in earth's atmosphere. (which does effects radio signals, and introduces uncertainty because of weather change)- Since quasar's readings are more accurately known - by many previous observations - one can "calibrate" the readings.

- One good example is our ordinary GPS in the car. Typical accuracy is about 20 meters. (Again main cause of uncertainty is errors introduced by local weather or similar conditions). With quasar type corrections, one can reduce that uncertainty to a few centimeters (or better)! This is not hard, by the way. (The Wide Area Augmentation System (WAAS) used in air navigation is accurate, perhaps to about 1 meter - uses ground based references instead of quasars - Best GPS used in surveying can reach accuracy about a cm)

- You don't have to have a super accurate clocks in GPS. As long as the frequency is stable ( even for a short time while GPS calculates and gives the reading), it can be calibrated with accurate frequencies from GPS transmitters in the satellites. (Actually, GPS can thus be used as a cheap and accurate "atomic clock", if you are ready to provide a little software to do this)

Lastly - A pulsar clock was installed in the European Parliament in Brussels, Belgium, some time ago. Here is
the picture of first Pulsar clock installed in Gdańsk, Poland (in 2011)

[Amber G.]

...The accuracy above is borderline unbelievable. .. Similarly, the nano-radian accuracy is also amazing..

Yes, to put in perspective, as some describing ICRF2 .. said - about the thickness of a 0.7-millimeter mechanical pencil lead in Los Angeles as viewed from Washington, D.C.

Also just for fun, check out Nasa's RISE (ROTATION AND INTERIOR STRUCTURE EXPERIMENT) to be sent with Insite.. has this on the website:
http://insight.jpl.nasa.gov/rise.cfm

RISE uses the lander's X-band radio link for Doppler tracking of the lander's location with an accuracy of a handful of cm.
(vs about few meter(s), as I mentioned for MOM's case in my post..)

Since the lander is attached to the planet, this allows the measurement of the rotation of Mars, and particularly variations in its rotation axis. (extremely small wobbling)

These rotational variations are related primarily to the size and state of the core, through its effect on the moment of inertia and damping of Mars.

(By tracking wobble, scientists can determine the distribution of the Mars internal structures.. etc)
I am just giving one example of how accurate these navigation systems have evolved now ..

[Amber G.]

And one small detail to complete the GPS discussion: what is the accuracy of the clock in a GPS receiver- would that be 10-7 sec (i.e. voltage-based oscillators) per Mort's post?

As I posted before, GPS receivers do not have to have super accurate clocks (or oscillators)..as a GPS receiver do not directly computes time or frequency, rather they use GPS to discipline an oscillator that may range from a quartz crystal ( low-end as I have in my car) to oven-controlled crystal oscillators (OCXO - see Mort's message) in some units, to rubidium at high end.(see Mort's post - this, some times is also classified as atomic oscillator -type some places use for synchronization in telecommunications networks which can not afford true atomic clocks).

So in Mort's classification, perhaps one may include GPSDO - as these devices are technically known as GPS-disciplined oscillators .

(BTW the first GPS unit I bought (Magellan GPS with a magnetic hard disk), a few years ago, was sort of "jail broken" and was made into an accurate clock by me and my sons - it was fun and easy)

Added later: from wiki

GPSDOs are capable of generating frequency accuracies and stabilities on the order of parts per billion for even entry-level, low-cost units, to parts per trillion for more advanced units within minutes after power-on, and are thus one of the highest-accuracy physically-derived reference standards available.

[Amber G.]

Sorry for multiple postings.. but there are a few nice pictures at:

Glorious Global 3-D Mars from ISRO’s MOM and ESA’s Rosetta
such as:

[SriKumar]

AmberG Thanks for the links....the one on Delta DOR is pretty detailed....pretty recent (2013), will go through it. The pulsar clock picture was interesting too....the last digit in the time (1/1000 sec) is very clear....fast camera/film.

[Amber G.]

Meridiani Plains was clearly seen in MOM's photo. Here is a panoramic view from the ground perspective..

Taken by Opportunity in mid-September 2014 (Images that compose the Wdowiak Panorama- beautiful view of Wdowiak Ridge from the south looking north, and beyond that you can see the Meridiani Plains, Murray Ridge, and into Endeavour .. Although the official Pancam version has not yet been released, Stuart Atkinson, MER poet, planetary author, and member of UMSF.com, "stitched" the panels together and processed them in his Martian Technicolor version



(Source: http://www.planetary.org/ )

[JayS]

The accuracy above is borderline unbelievable.

Everything about the space is unbelievable. I remember to have read about this spacecraft from NASA (can't remember name, but i think it was used for experimentation regarding gravitational wave) which had an accuracy so high, to put it in perspective, it could measure difference in distance equivalent to thickness of normal paper sheet from from some ~250 miles away.

[SaiK]

mort, you are an atomic clock man!

you are right on mom's dock!:

3. Rubidium clock. Accuracy 10^-11 sec. Commercially available for around $2K and are used as reference clocks for communication systems and computer networks. If I were designing MOM, I would consider using a rubidium clock.

some online refs:

http://wap.business-standard.com/articl ... 195_1.html
A highly accurate Rubidium atomic clock is part of the navigation payload of the satellite.

http://seemasingh.in/tag/isro/
The clock system works by having an IRNSS Network Timing facility (IRNWT) on ground and a Rubidium Atomic Frequency Standard, or a Rubidium clock, on-board the satellite. The ground facility established at Byalalu, near Bangalore, provides extremely accurate and highly stable IRNSS network time which consists, to use the orchestra analogy, an ensemble of Hydrogen Masers and Caesium clocks. These run a timescale with a stability specification of 5 x 10 -15 seconds over a day. (In other words, their drift, which all clocks exhibit, is of the order of a millionth of 5 nanoseconds in a day.)

The IRNSS time is provided with an uncertainty of less than 20 nanoseconds with respect to the UTC (Co-ordinated Universal Time).

Up in the satellite, the Rubidium clock provides the frequency reference on which the navigation signals are generated and broadcast by the satellite. But placing this clock in the satellite posed a challenge of its own. It required a thermal management of the spacecraft because the stability of a Rubidium clock is highly dependent on the temperature. It has to be maintained within a temperature range of +/- 1 ⁰C, when the satellite itself is subjected to the harsh environment of space where the temperature variation is from +150 ⁰C to – 50 ⁰C depending on the side of the satellite that faces the blazing sun or the freezing outer space.

The engineers had to devise a state of the art thermal control systems, says Ganeshan, using a procedure called ‘Yaw flipping” in which gradual rotation of the satellite on its Yaw (the earth pointing) axis is adopted. This flipping maneuver avoids the sun from directly illuminating the panel where the Rubidium clocks are placed. This ensures the stability of the on-board clock which is continuously monitored from the ground control centres and is synchronized with the IRNSS network time through the navigation software.

Simply put, the navigation system works like this: the satellites transmit their position and a precise time; using this information and the speed of light, a ground receiver calculates its distance from a satellite. By using data from four or more navigation satellites, a typical GPS/GLONASS/Galileo/IRNSS receiver determines its location to within 20 metres.

and
http://www.ijapm.org/papers/109-P20007.pdf

[member_28108]

https://twitter.com/raju/status/518917700597612544

Raju Narisetti ‏@raju 2h1 hour ago
The @nytimes editorial page editor Andrew Rosenthal has issued an apology for this cartoon on India's Mars success

Conveniently not in the original format but in facebook.

[SaiK]

yeah! they bomb the hell outta Iraq, and would not hesitate an apology for misdirected weapons falling on bad targets (especially women and children). after the damage has done, they go apologizing. a tit4tat is what needed and not apologies. it is their game after all. days are not far, that their wrong doings going to return back as evil for them... and it will happen as an eventuality.. they think these sins are temporal and purgatory which is totally wrong.

[Amber G.]

May be of interest to a few hakim sahibs here in this thread.. specially after all this talk of GPS and navigation and things of that nature...

The noble prize in Medicine went for "discoverers of brain’s 'inner GPS'..and navigational system...

Also interesting is the fact - O'Keefe switched to Medicine in school, after jumping from subject to subject including aeronautics at college ...

[Amber G.]

It was reported that ISRO received some thing like 15,000 congratulatory messages from across the globe (10000+ were on September 24 itself)

Virtually all from most of the countries and India were good. (US reaction, specially from ordinary people and scientific community was very positive).

OTOH, for fun and amusement, Here is reaction from Prof Xerox Khan who tweeted -

..India had reached Mars at a price seven times less than that of a metro bus project while Pakistani PM Nawaz Sharif was enjoying his US visit spending $1 lakh per day of taxpayers' money.
...
India was once a child to us in terms of technology, but corrupt politicians arrested our scientists, closed researches on US direction..

(BTW Prof Xerox Khan calls himself as "A Muslim, a human being , a Pakistan lover, a person who created balance of power & stopped wars in South Asia, founder of Islamic bomb in eyes of western media.")

Just for record, Dawn, and other newspapers/website were not bad.. (for example - Dawn said ""This is an example of supreme expertise of Indian scientists and technology. Hats off to you all. We should feel proud as India has broken the superiority of the West in space." )

[member_28108]

Full disc image from @MarsOrbiter. South of the cloud formation is Elysium- the 2nd largest volcanic province on Mars

[Mort Walker]

AmberG,

You bring up an excellent point about Pulsars being very accurate clocks. The question is why? And perhaps you can explain this better.

A Pulsar is a neutron star which should exhibit the qualities of a Bose-Einstein condensate. That is, it is very cold and near absolute zero, or between 0-1 degree Kelvin. If you have an oscillator who's material is near absolute zero, then the thermal noise floor power will be very low. Hence, it will have very low phase noise and excellent accuracy. The problem is that the tools we have to measure the oscillations of the Pulsar are not as good as the Pulsar itself.

For reference about thermal noise, see:

http://en.wikipedia.org/wiki/Johnson%E2 ... uist_noise

[SaiK]

what is that white spot on right-edge in the middle (at about 20* angle from center)?

[SagarAg]

Looks like a cloud saik garu.
The first image sent by @MarsOrbiter was of the bottom part of this new release, right?

[SBajwa]

Check this out.

Plan to colonize Mars

http://www.mars-one.com/mission/roadmap

[Amber G.]

AmberG,

You bring up an excellent point about Pulsars being very accurate clocks. The question is why? And perhaps you can explain this better.

A Pulsar is a neutron star which should exhibit the qualities of a Bose-Einstein condensate. That is, it is very cold and near absolute zero, or between 0-1 degree Kelvin. If you have an oscillator who's material is near absolute zero, then the thermal noise floor power will be very low. Hence, it will have very low phase noise and excellent accuracy. The problem is that the tools we have to measure the oscillations of the Pulsar are not as good as the Pulsar itself.

For reference about thermal noise, see:

http://en.wikipedia.org/wiki/Johnson%E2 ... uist_noise

Yes, a Pulsar is a neutron star (or binary neutron star-system), but the 'oscillations' are not "nuclear" in nature. The basis is simply due to gravitational forces - conservation of angular momentum makes it spin (or rotation of binary stars) very fast when the star (whole solar system) system compressed into a very small sphere (aka an often given analogy of a skater spinning faster when arms are brought in). This small sphere (highly magnetized, a rotating neutron star) emits a beam of electromagnetic radiation. This radiation can only be observed when the beam of emission is pointing toward the Earth..

(This is why, basis of Pulsar is "Ephemeris Time" (and not "atomic time)) which is based on Gravitation
, and for example, studying these can also tell about things like gravitational waves and if the gravitational constant is changing compared to "nuclear forces" over time etc)

(BTW, definition of unit of time, second, was based on gravitation (movement of planets) till 1967 and then it was changed to be based on Cs clock)(Historically "second" was based on spin of earth( 1 day = 86400 days)..but since spin of earth is not that stable, in 1960 it was changed to movement of planets wrt to Sun, and in 1967 it changed to atomic standard)

***

Coincidentally there is a post by Bade in Physics dhaga, which gives a link: http://www.slate.com/articles/health_an ... nobel.html which talks about Jocelyn Bell Burnell, who discovered the first Pulsar and ought to have gotten/shared the Noble. That is an interesting read about
the discovery of pulsars.

***
nileshjr, yes the resolution you gave ( thickness of normal paper sheet from from some ~250 miles away) is on the mark. And yes, pulsars are involved in finding gravitational waves. (Actually there was some excitement about people finding a credible proof for gravitational waves - (March of this year ) but most current thinking is having a little doubt in those results.

[Amber G.]

Okay folks -

Those with Fast (Better F stop - as large as aperture - more resolving power) and telephoto lenses try to
photograph Sididng Spring - The comet MOM/Mars will encounter on October 19th)

If you can attach your DSLR to a telescope, it will be better, but I think, if the conditions are good, a good DSLR with 200 mm lens and tripod may work.

Any interest?

[SaiK]

nearest observatory for me is 15 miles.. interested but may not have time. normally they will loan take home telescopes against membership.

[member_28108]

I have a 3 inch reflector.Can it be seen with that ?
Prasanna

[NRao]

FE-3 + 500mm?

[Amber G.]

^^^ I think, if the you get a clear dark sky, both should work. (A binocular should work too).. (500 mm lens will work, IMO very very well -specially if one can find a good tripod - equatorial mount will be super)

(Of course, no one knows for sure, Comets have a history of disappointing (or surprising) aam-janta a lot- as brightness of comet can change the way it "heats up" )

More - There is a NASA briefing (http://mars.nasa.gov/news/whatsnew/inde ... ewsID=1723 and opportunity for Q&A (See above for details)

Also, the site, for example http://mars.jpl.nasa.gov/comets/sidingspring/ gives very good information about how to view the event.

There are very good experts in brf, (see the photography dhaga) so I will leave it to them.

[member_28108]

FE-3 + 500mm?

This telescope
http://www.meade.com/catalogsearch/result/?q=114EQ-ASTR
(Actually 4.5" My Son got it as a prize for winning a competition hosted by TI when he was in school).

My Son used to rig it up for me to see but now he is in College so I have to read it up and set it !

[VinodTK]

India's Mars Orbiter sends back first 3D images of Mars

[SaiK]

as usual, a gem from TSS
http://www.frontline.in/science-and-tec ... epage=true

The reverse manoeuvre of the spacecraft began at 7-42 a.m. to orient its antenna towards the earth to resume communication. The orbiter’s solar panel was oriented towards the sun to generate power. The Mars occult ended at 7-45 a.m.

Kesava Raju explained why it was necessary to reduce the spacecraft’s velocity by 1.09 km/s to enable the spacecraft’s entry into the Martian orbit. He said: “When we reach Mars, the spacecraft will have a velocity of 22.57 km/s, whereas Mars’ velocity is 25.71 km/s. It means the spacecraft is slower. When the spacecraft is under the influence of Mars’ gravity, it reaches the closest point to Mars. At that time, it will attain a velocity of 5.7 km/s. But we do not require 5.7 km/s for our spacecraft to reach the desired orbit. We require 4.6. So the orbiter’s velocity is reduced from 5.7 km/s to 4.6 km/s. The velocity decrement is 1.1 km/s.”

and then...

The accuracy of our prediction comes from our communication system, which has worked to perfection. We were able to communicate about 224 million km of radio distance with our orbiter. Our ability to communicate can go up to 375 million km of radio distance,” Arunan said.
..............
“…We have sensors and transmitters on board the orbiter that can sense the failure and reconfigure the redundant system on the spacecraft on their own. The reconfiguration will take place autonomously in the orbiter,” said M. Annnadurai,.....

“In case of unexpected events, the spacecraft has to survive on its own. If the spacecraft’s attitude is not proper, we will not be able to communicate with it from the earth. So the eight thrusters should simultaneously burn with the LAM and orient the spacecraft’s attitude in such a way that we can contact it from the earth. All these manoeuvres should take place on [commands from on] board itself and they should happen automatically at the required time.” In Radhakrishnan’s assessment: “If one were to identify two important elements in the Mars orbiter, it is its autonomy and navigation towards Mars.”

..lot more info! read it!

and another great article:
http://www.frontline.in/science-and-tec ... epage=true
Giant leap

[SagarAg]

Mars Orbiter Mission shifts orbit to take cover from Siding Spring

With only 10 days remaining until the arrival of Comet Siding Spring at Mars, ISRO has shielded the Mars Orbiter Mission (MOM) from the comet.

Siding Spring's closest approach to Mars will be on October 19 at 18:32 UTC / 11:32 PDT, or midnight IST. It will pass by at a distance of 134,000 kilometers and a relative velocity of 57.4 kilometers per second.

Following orbit insertion on September 24, MOM’s orbit had been 423 by 80,000 kilometers. Kiran Kumar, Director of ISRO’s Space Application Centre, said that on Tuesday MOM’s orbit was altered so as to move it behind the Red Planet when the comet arrives. For this maneuvering on Tuesday, the spacecraft consumed 1.9 kilograms of fuel.

At the comet's closest approach, MOM will be 400 kilometers away from the surface of the Red Planet on the opposite side from the comet. Kumar said that MOM’s highest altitude was currently 72,000 kilometers, which is expected to remain unchanged even after the departure of the comet. The minimum distance between MOM and the comet on October 19 will be around 140,000 kilometers. According to him the comet will have no negative impact on the future performance of the spacecraft or its science mission. A few days ago, the mission tweeted:

Kumar said that MOM will carry out observations of the comet and its Mars Colour Camera will click images of it. ISRO's chairman, K.Radhakrishnan, had stated earlier that the arrival of the comet will be viewed as an opportunity for doing scientific observations. ISRO and NASA scientists will collaborate in analyzing data generated by MOM and MAVEN related to the Comet Siding Spring.