Chandrayan-1 moon mission

[Arunkumar]

Any one know, What is the attitude control on MIP? Spin stabilized?
Thanks

Yes.....it is.

http://www.isro.org/chandrayaan/htmls/mip.htm

[manoba]

Earthe-Moone-Marse as a single complex.

An economic and Strategic importance?

Wow, where from these guys, humble, down-to-earth visionaries, sons of soils get great ideas, I wonder.

[Gerard]

Isro engineers told The Telegraph that shortly before the launch of Chandrayaan-1, they had decided to add two intermediate orbits to its journey.

The initial plan was to inject the spacecraft into three Earth orbits, each with a greater apogee — 22,800km, 37,000km and 74,000km — before it was guided into a fourth orbit that would take it close to the moon.

But mission engineers decided to add two orbits — with apogees of about 164,000km and 267,000km — instead of leaping directly from 74,000km to the final Earth orbit at 384,000km.

They believe this will give them more experience of the deep space environment where the gravitational tugs of the moon and the Sun become significant. “We’ll be able to make precise assessments of these gravitational influences,” Nair said.

“When we’re climbing stairs, it’s better to go a step at a time,” Mylswamy Annadurai, project director of Chandrayaan-1, said.

link

[Arun_S]

Ahh.. as mentioned by Arun_S, the time of burn is less and less... only 9 minutes for 75000 to 164000

This burn to move from 74K Km to 164k Km should have consumed ~ 85 Kg fuel.
Next burn to lift it to 267,000 Km should use ~29 Kg fuel,
and the last earth orbit 384,000Km use only ~13 kg fuel.

I do not have time to figure out from press reporting accurate dry weight estimate of Chandraayan, hence I am calling fuel requirements as approximate. If someone can tell me that I can get you more accurate estimate.

[juvva]

Ahh.. as mentioned by Arun_S, the time of burn is less and less... only 9 minutes for 75000 to 164000

This burn to move from 74K Km to 164k Km should have consumed ~ 85 Kg fuel.
Next burn to lift it to 267,000 Km should use ~29 Kg fuel,
and the last earth orbit 384,000Km use only ~13 kg fuel.

I do not have time to figure out from press reporting accurate dry weight estimate of Chandraayan, hence I am calling fuel requirements as approximate. If someone can tell me that I can get you more accurate estimate.

Googled: 504 KG dry mass as per wiki and other sources.

[anupmisra]

Earthe-Moone-Marse as a single complex.

Are you making fun of the way the distinguished ex-President Kalam speaks?

[svinayak]

http://www.hindu.com/thehindu/holnus/00 ... 241221.htm
Sci. & Tech.
Dhaka daily hails India's moon mission

Dhaka (IANS): A prominent Dhaka daily Friday hailed India's maiden moon mission Chandrayaan-1 and hoped that its spin-off would help the entire South Asian region.

There was "justifiable pride" in the technological feat of scientists of a developing country, The Daily Star said in an editorial.

"The launch of the lunar mission is, briefly, one very powerful sign of the advances in technology that India has been making in recent years. It is at the same time a broad hint that where the exploration of space is concerned, the Indians have finally come of age.

"We take this opportunity to congratulate the people and government of India on the launch of the Chandrayaan 1 mission to the moon. One hardly needs any telling that, for a developing country like India and indeed for the region, the venture is cause for justifiable pride."

"That sense of pride as well as belonging is enhanced by the fact that India is an important component of SAARC (South Asian Association for Regional Cooperation). As a fellow member of the South Asian regional organisation, we feel that the stride Delhi has taken in space will have a positive impact on scientific development for Indians in particular and for their neighbours and for developing countries in general.

Drawing a larger Asian picture, the newspaper said: "The achievement is but the latest step where progress in space related matters by Asian nations is concerned. China and Japan have already become part of what is now an expanding global space programme.

"Against such a backdrop, although India has achieved a remarkable feat, as a developing country it has yet to go quite some way before it can climb on to the perch that other nations have attained as members of the space club."

The newspaper added that there was little doubt that with its recent economic and technological strides, India would focus on providing its poor with better amenities.

"It is our expectation as well as that of people in the bigger South Asian region that India's foray into space will yield social benefits common to all through a sharing of knowledge about space and a utilisation of such knowledge here on earth. Chandrayaan 1 will map the surface of the moon. What new facts about the lunar body such an exercise might throw up can only be imagined," it said.

Related stories:

http://www.smh.com.au/news/sport/cricke ... 40356.html

Fly me to the moon: India pass Australia as they launch into higher orbit

October 25, 2008
Page 1 of 2 | Single page
INDIA is sending a spaceship to the moon, has won the Booker Prize, is winning the World Chess Championship and is about to knock over the cricket champs as well. No wonder confidence is high.

Shrugging off a lingering inferiority complex, the nation is emerging as an affluent, ambitious place comfortable in its own skin. And the news gets worse for the embattled Australians. Anil Kumble has had a cup of chai with Radhey Shyam Sharma, his closest pal in Delhi. Mr Sharma is not a politician in a city full of them, or a businessman, or a fellow photographer, or a relation, or a school friend. He prepares the wickets at Feroz Kotla Shah Stadium, scene of the third Test.

http://www.indianmuslims.info/news/2008 ... ssion.html

[manoba]

Earthe-Moone-Marse as a single complex.

Are you making fun of the way the distinguished ex-President Kalam speaks?

On the contrary. Didn't you read the rest on my post?

Look at the way he speaks with a child's enthusiasm (Compare it with Bush or the arrogant Dick VP. Well, I know that is a nasty comparison). That too a man who has achieved so many heights.

(By the way thanks for correcting the "President" part).

[a_kumar]

the kayuga satellite looks like it released one or two comms relay satellites
to resolve the LOS issue with earth. details about kayuga are hard to
find in english part of web though.

The following link shows what the two satellites are helping with.
Kaguya - VRAD & RSAT

Another interesting link shows how the three satellites talk to Earth stations..
Kaguya - Ground Stations

As am searching for information, I am beginning to see that Kaguya (like Chandrayaan-I) have kept lot of information on the web, but am yet to find much about Change1.. Official statement rues that if it weren't for a lot of fuel spent on manuevering the craft on its way to moon, it would have lasted lot longer..
Chang'e1 may not end with a bang

Earlier reports said scientists hoped precise maneuvering might have saved 200 kg of fuel during the satellite's 380,000-km journey to its current orbit, possibly prolonging its lifespan.

[svinayak]

http://www.blinkx.com/video/india-launc ... xzmtKqJRYA

[Gerard]

but am yet to find much about Change1

At least it had Gola's blessing...

Excellency,

It gives me great pleasure to congratulate you and the friendly people of China for the successful launch of the first Chinese lunar orbiter, Chang’e 1 on a planned year-long exploration mission to the Moon.

It is indeed a glorious moment of pride for the great Chinese people. The launching is an outstanding example of China’s economic and technological modernization, a goal that China has pursued with admirable success since 1979. The people of Pakistan share this moment of happiness with our Chinese friends.

I would like to avail this opportunity to wish the Chinese Government successful completion of their future endeavours in space exploration, especially the plan for a manned mission to moon by 2020.

Please accept, Excellency, the assurances of my highest consideration.

General Pervez Musharraf

President of the Islamic Republic of Pakistan

[Gerard]

link

If three more firings of the liquid apogee motor on Chandrayaan-1 are successfully accomplished on October 29, November 3 and November 8, the spacecraft will reach its final abode of 100 km around the moon on November 14th or 15th. Commands will then be radioed from the Spacecraft Control Centre to Chandrayaan-1 to eject the Moon Impact Probe (MIP) which “sits like a hat on top of it.”

[rahulm]

Placing the Indian flag on the moon

http://au.youtube.com/watch?v=DVIE7Ph-4 ... re=related

Has some nice videos and animation. Apologies,if posted earlier.

[svinayak]

http://au.youtube.com/watch?v=LK3ohtzfk2A

[SriKumar]

During this manoeuvre which was initiated at 07:08 IST, the spacecraft’s 440 Newton liquid engine was fired for about nine and a half minutes. With this, Chandrayaan-1 entered a much higher elliptical orbit around the Earth

.
Is there any picture available of how Chandrayaan looks like, in this stage? I assume the satellite is encapsulated in a '5th stage' with a small rocket motor?

Un-related question: The moon mission was supposed to be launched earlier this year, and was postponed. Outside of fueling up the rocket, are there other things one has to be concerned with, when there is a postponement of a launch by several months? Or can a rocket (and payload) sit around for a bit and not be affected by delays?

[UPrabhu]

SriKumar,

Satellite itself is the 5th stage. Most satellites, especially the geostationary ones have a LAM (Apogee motor). Chandrayaan just has a similar motor but one which fires at Perigee to increase the Apogee. It also carries more fuel as fraction of total mass to reach the moon, compared to say Communication satellites.

[SriKumar]

Satellite itself is the 5th stage. Most satellites, especially the geostationary ones have a LAM (Apogee motor). Chandrayaan just has a similar motor but one which fires at Perigee to increase the Apogee.

Thanks. It surprises me a bit that the satellite has no hard-shell protection, but if orbiting statellites dont need it, I suppose neither does CY. I found this wiki pic. http://en.wikipedia.org/wiki/Image:Chandrayaan-05.jpg I assume that the red nozzles in the first picture are the rockets used to accelerate and orient the satellite (and perhaps there are other nozzles not seen in the picture).

[Praveen]

Satellite itself is the 5th stage. Most satellites, especially the geostationary ones have a LAM (Apogee motor). Chandrayaan just has a similar motor but one which fires at Perigee to increase the Apogee.

Thanks. It surprises me a bit that the satellite has no hard-shell protection, but if orbiting statellites dont need it, I suppose neither does CY. I found this wiki pic. http://en.wikipedia.org/wiki/Image:Chandrayaan-05.jpg I assume that the red nozzles in the first picture are the rockets used to accelerate and orient the satellite (and perhaps there are other nozzles not seen in the picture).

Nope, those Red ones are star sensors.
http://www.isro.org/pslv-c11/brochure/page8.htm

[SSridhar]

link

If three more firings of the liquid apogee motor on Chandrayaan-1 are successfully accomplished on October 29, November 3 and November 8, the spacecraft will reach its final abode of 100 km . . .

What about the firings to change the plane midcourse and then to insert Chandrayaan-I into lunar orbit once moon captures the spacecraft ?

[NRao]

India's First Lunar Mission Heralds New Cooperation

Oct 26, 2008

By Neelam Mathews

India is moving into a more active role in the international community of spacefaring nations as its Chandraýýyaan-1 probe heads toward lunar orbit following a flawless launch Oct. 22.

With the start of its first mission beyond low Earth orbit, the Indian Space Research Organization (ISRO) is moving ahead on its joint Chandrayaan-2 robotic lunar lander mission with Russia, and is laying plans for a new $122-million launch complex and astronaut-training facility, pending the expected government approval for a two-seat manned Earth orbiter.

A formal government nod to the human-rated vehicle likely will come in the next few months, following approval by India's Space Commission. While the human flights would originate at this ISRO facility on Sriharikota Island in the Bay of Bengal, ISRO Chairman G. Madhavan Nair holds open the door to possible international cooperation.

"Technology elements required for improving the reliability of launch systems have been identified," he says. "Crew escape and mission management system have to be in place. We do not have any proposal for cooperation with other countries, but we are not averse to it."

Controllers at ISRO's Spacecraft Control Center (SCC) in Bangalore are maneuvering Chandrayaan-1 toward lunar orbit, using the spacecraft's 99-lb.-thrust Liquid Apogee Motor (LAM) - derived from the Insat program - to raise its apogee in steps. The first firing Oct. 23 lifted the probe's highest point from 22,860 km. (14,200 mi.) to 37,900 km. in an 18-min. burn.

Chandrayaan-1 is scheduled to reach its target orbit 100 km. above the Moon's surface on Nov. 8, after a final kick from the LAM to send the probe to the Moon and another to slow it into orbit there. If the maneuvering is successful, India will join China and Japan with satellites in orbit around the Moon, where the European Space Agency, Russia and the U.S. also have placed robotic orbiters in the past.

Once the Chandrayaan-1 orbit is circularized, the spacecraft's Moon Impact Probe will be ejected. The impactor is designed to demonstrate technology for a future Indian soft landing on the Moon, although Russia is scheduled to build the lander for the Chandrayaan-2 follow-on mission.

Under an agreement between ISRO and the Russian space agency Roscosmos signed last year in Moscow (AW&ST Nov. 19, 2007, p. 17), India will provide its Geosynchronous Satellite Launch Vehicle (GSLV) and develop another lunar orbiter. Like the current mission, Nair says that vehicle may be open to international participation as well.

"Based on our scientists' requirements, we will open up Chandrayaan-2 to foreign payloads," he tells Aviation Week & Space Technology.

The solar-powered Chandrayaan-2 rover will have an operating lifespan of about a month and will weigh 30-100 kg. (66-220-lb.), depending on whether engineers decide on a semi-hard or soft landing. Among potential partners on the Chandrayaan-2 mission is NASA, which signed a framework agreement on future cooperation with ISRO earlier this year.

"It's very possible that NASA will fly on future Indian missions," says NASA spokesman David Agle.

India is also in the early stages of studying a mission to Mars, again using the GSLV. The mission would take place within five years after the government gives clearance.

"Our scientific community has proposed an outline of a Mars exploration," Nair says. "We are studying the proposal. If [it] is interesting, we will pursue that."

Chandrayaan-1 enjoyed a textbook launch at 6:22 a.m. local time Oct. 22 (8:52 p.m. Oct. 21 EDT) on its Polar Satellite Launch Vehicle (PSLV), after a 52-hr. countdown, following a day of rain and lightning that threatened a postponement.

"With this success we are ready to take on many more challenges," said Mission Director George Koshy. "This proved PSLV is a weatherproof vehicle that can be used for taking a spacecraft to Mars."

Another emotional ISRO scientist said, "Our baby is on its way to the Moon."

After an unsuccessful debut in 1993, the PSLV has come a long way. In its 14th consecutive successful flight - of 30 conducted from this facility 80 km. north of Chennai - PSLV-C11 took 18 min., 12 sec. to get Chandrayaan-1 into its initial transfer orbit with a perigee of 255 km., inclined 17.9 deg. to the Equator with a 6.5-hr. orbital period.

The four-stage launcher used for Chandrayaan-1 weighed 320 metric tons at liftoff, using six uprated strap-on boosters carrying 12 metric tons of solid propellant each, instead of the standard nine metric tons. The first and third stages also use the same solid propellant, while the second and fourth stages use storable liquid hypergolic propellants.

The 1,380-kg. spacecraft carries a suite of 11 instruments - divided among those produced domestically and those supplied by ISRO's international partners in the mission - all intended to better characterize the Moon's terrain and mineralogy in support of future robotic and human exploration. Indian scientists and engineers developed five instruments for the mission: The Terrain Mapping Camera, to map surface topography; the Hyperspectral Imager, for mapping minerals on the lunar surface; the Lunar Laser Ranging Instrument, to determine the height of surface features; the High Energy X-Ray Spectrometer, to search for uranium, thorium and possible water-ice deposits at the poles; and the Moon Impact Probe.

There are six foreign instruments on the spacecraft. The European Space Agency's Imaging X-ray Spectrometer was developed by the Rutherford Appleton Laboratory in the U.K. and the ISRO Satellite Center in Bangalore to look for magnesium, aluminum, silicon, iron and titanium with an X-ray fluorescence technique. ESA also funded the Smart Near Infrared Spectrometer, a mineral mapper developed by Germany's Max Planck Institute to study how lunar surface features were formed.

Sweden's Institue of Space Physics and the Space Physics Laboratory at ISRO's Vikram Sarabhai Space Center, Tiruvananthapuram, developed the Sub-kiloelectronvolt Atom Reflecting Analyser for ESA to study the Moon's surface composition and magnetic anomalies. A Radiation Dose Monitor developed by the Bulgarian Academy of Sciences will characterize the radiation environment around the Moon.

NASA provided two instruments for Chandrayaan-1, the Miniature Synthetic Aperture Radar (MiniSAR) prototype developed by the Johns Hopkins University Applied Physics Laboratory and the U.S. Naval Air Warfare Center to look for water ice in the permanently shaded craters at the lunar poles, and the Moon Mineralogy Mapper (M3), an imaging spectrometer. Developed at Brown University and the Jet Propulsion Laboratory, the M3 is designed to assess and map lunar mineral resources at high spatial and spectral resolutions.

[Lalmohan]

question for orbital mechanics gurus - i was under the impression that lunar shots did an elliptical boosting (earth) orbit and then flew a 'S-shaped' trajectory towards the moon and set up a new (lunar) orbit. The Chandrayan appears to be doing larger ellipses until it captures the lunar orbit... have i got that right?

secondly - i appreciate that deep space effects, e.g. gravitational disturbances from jupiter and other bodies play a larger role in the lunar mission than say LEO/MEO and even HEO missions - are these deeply guarded secrets by NASA and the Russians? Or is ISRO doing some new fundamental experimentation?

finally - i don't think India should rush towards a manned mission soon - it only adds expense. a more cunning bania way forward is to collaborate with ESA and/or Japan to commercialise large vehicle launches from India and participate in Space Lab/Mars Mission type programmes which builds our overall knowledge base and pools expense with like minded nations. leave the manned mission/space walk on table mijjile slapping to the ever-inferior feeling Chini bhais and their little gubo partners in green princess dresses.

[svinayak]

Chandrayaan’s orbit raised again

Special Correspondent
http://www.hindu.com/2008/10/27/stories ... 981200.htm

— Photo: K. Murali Kumar

Alert eyes: Scientists manning the monitoring consoles on October 25 at the Indian Deep Space Network Control Centre at Byalalu village near Bangalore, where two huge bowl-shaped antennae have been set up to track and communicate with Chandrayaan-1.

CHENNAI: “An air of professionalism and cool-headedness” prevailed at the Spacecraft Control Centre (SCC) at the ISRO Telemetry Command, Control and Tracking Network (ISTRAC), headed by S.K. Shivakumar at Bangalore, where radio frequency specialists radioed commands on Sunday morning to the engine on board Chandrayaan-1 to fire, an ISRO official said.

The engine fired for about nine-and-a-half minutes from 7.08 a.m. on Sunday. This successful firing lifted the spacecraft’s orbit from an apogee of 74,715 km and a perigee of 336 km on Saturday to its present apogee of 1.64 lakh km and a perigee of 348 km. The spacecraft has almost reached half the distance to the moon, which is 3,84,000 km away from the earth. In this orbit, Chandrayaan-1 takes about 73 hours to go round the earth once.

At this distance from the earth, the electric transmitter power with which Chandrayaan-1 “whispers” is so low that the signals received from it are very feeble and they have to be amplified, the official explained. “So it is quite a big challenge to communicate with the spacecraft when it is travelling deep in space,” he added.

The two antennae with a diameter of 32 metres and 18 metres that belong to the Indian Deep Space Network (IDSN) of ISRO at Byalalu village, near Bangalore, were playing a crucial role in tracking and communicating with Chandrayaan-1 in such a high orbit. When the spacecraft becomes operational, these huge bowl-shaped antennae will also receive scientific information from the 11 instruments on board Chandrayaan-1.

If three more firings of the liquid apogee motor on Chandrayaan-1 are successfully accomplished on October 29, November 3 and November 8, the spacecraft will reach its final abode of 100 km around the moon on November 14th or 15th. Commands will then be radioed from the Spacecraft Control Centre to Chandrayaan-1 to eject the Moon Impact Probe (MIP) which “sits like a hat on top of it.”

The MIP, which will crashland on the moon’s surface, will be a technological forerunner to India landing a rover in the moon around 2012-2013 as part of Chandrayaan-2 mission with Russia.

After the MIP is ejected, the remaining 10 scientific instruments on the spacecraft will be switched on, one after the other.

[Bade]

question for orbital mechanics gurus - i was under the impression that lunar shots did an elliptical boosting (earth) orbit and then flew a 'S-shaped' trajectory towards the moon and set up a new (lunar) orbit. The Chandrayan appears to be doing larger ellipses until it captures the lunar orbit... have i got that right?

secondly - i appreciate that deep space effects, e.g. gravitational disturbances from jupiter and other bodies play a larger role in the lunar mission than say LEO/MEO and even HEO missions - are these deeply guarded secrets by NASA and the Russians? Or is ISRO doing some new fundamental experimentation?

finally - i don't think India should rush towards a manned mission soon - it only adds expense. a more cunning bania way forward is to collaborate with ESA and/or Japan to commercialise large vehicle launches from India and participate in Space Lab/Mars Mission type programmes which builds our overall knowledge base and pools expense with like minded nations. leave the manned mission/space walk on table mijjile slapping to the ever-inferior feeling Chini bhais and their little gubo partners in green princess dresses.

Once captured in Moon orbit the orbital plane can be corrected to be in moon's polar orbit as part of the final firings. SSridhar too had earlier referred to it.

There is nothing fundamental which is a state secret as far as orbital mechanics goes for planetary bodies. Astronomers do it routinely and the ability definitely exists in India even at some universities.

Waiting to collaborate with ESA/NASA/JAXA etc though good on paper it can delay things. One cannot expect to attract and retain the best talent at ISRO if the only thing they do would be to do commercial PSLV/GSLV launches. That is not challenging enough IMO for an organization as large as ISRO.

[vsunder]

Lalmohan: The Chandrayaan spacecraft is on a perfect Hohmann transfer orbit to the moon so S shape is very bad energetically. Google Hohmann transfer and find out what it is. It is energetically the most efficient orbit for obvious reasons. However it takes the longest possible time. I was very happy to see that the energetically efficient orbit was selected.

John Snow: Your question earlier is related to the libration points in the three body problem, also called the Lagrange points. You can wiki it and see the five Lagrange points in a restricted three body problem. The graphics in the wiki entry show very clearly the equipotential lines and the valleys and saddles.
The Lagrange points also occur in Science fiction.
In principle stationing a spacecraft at L5 as has been suggested is a way to communicate with the dark side of the moon. Stability analysis of these Lagrange points shows that L3, L2 and L1 are saddle points. Perhaps Chandrayaan will be at L1 or L2, with some marginal stability in Lunar orbit perhaps, since L1 and L2 are saddles and unstable in certain maybe equatorial directions. In general the general solution of the three body problem is chaotic see Jurgen Moser's book.
However the restricted three body problem which Chandrayaan approximates has definite solutions and so
orbital mechanics calculations work. Restricted, because here the assumption is one of the masses is almost negligible compared to the other two and even sometimes one assumes the motions are planar.

The three body problem was first claimed by Poincare to be solved in his monumental paper in Acta Mathematica 1906. However there were serious gaps in his proof. But in the same paper he introduced such marvellous ideas, Poincare return map, twist maps, Poincare-Birkhoff fixed point theorem and amazing ideas in hamiltonian dynamics and symplectic geometry still basic tools in today's research.

Rahum M: Perturbation theory in this problem even appears in a problem in Loney's book, Dynamics of a particle, it was very instructive to do this problem 40 years ago, little realizing I was doing a toy problem on soemthing so serious and rich mathematically.
The general problem of variations in gravity was done as a formal power series by Linstedt around 1908 and
it was Sundmann a Finn who essentially proved Linstedt series converges in 1912. Lindstedt won a prize for the Swedish academy for this marvellous piece of work. However, for practical matters the convergence of Sundmann series is very slow and not very good for orbital mechanics calculations on a practical level. About 8,000,000 terms are needed. See google for all this or wiki entries.

Better methods are available nowadays. Here is web page with very detailed eigenvalue/stability analysis of the 5 Lagrange points in say the Earth-Moon-Chandrayaan system.
http://www.physics.montana.edu/faculty/ ... grange.pdf

The wiki entries have spectacular graphics for Lagrange points, wish I had that when I learnt all that.
Look at L5 and maybe India should put something there next in a earth-sun system.

[SwamyG]

Bade:
In one of the interviews Madhavan Nair had said ISRO has been receiving indications that people of Indian origin from NASA are interested to work in ISRO projects. Also he mentioned there are even some "foreigners" who are showing interest to work on ISRO projects. There was some talk off reverse brain drain.

[Rahul M]

thanks for the explanation vsunder sir.

my experience in this is limited to helping a coursemate develop an algo for numerically solving for the restricted 3-body problem, approximately equivalent to the one being talked about here. that was however a long time back !
the almost counter intuitive nature of L4 and L5 was really fun.

[Bade]

Bade:
In one of the interviews Madhavan Nair had said ISRO has been receiving indications that people of Indian origin from NASA are interested to work in ISRO projects. Also he mentioned there are even some "foreigners" who are showing interest to work on ISRO projects. There was some talk off reverse brain drain.

Honestly, if one has a permanent job at NASA why would he/she take the trouble to quit and head home to work for ISRO. More to the point, to be a NASA employee the first requirement is a US citizenship. ISRO only hires Indian citizens. Not even OCIs AFAIK. People who went back to ISRO whom I know, kept their Indian passports while in the US.

I think he is referring to Post-docs and other NASA contractor employees very likely, who have very few options to stay on in their field of choice in the US and are forced to search for employment elsewhere in the world. India now will be high up in their list from now on. No to belittle it, but that is how many US returned PhDs get back to the IITs/TIFR etc. when opportunities dry up in the west at the individual level.

[John Snow]

vsunder garu>> as always
mitha bhashyam
amitha vigyanam
sada bhoditham
Pranamahyam

V sunder garu
(speaks less
but infinite in knowledge
always imparts
I bow to thee)

Thanks for the gyaan.

[Lalmohan]

VSunder-ji - thanks, you've re-activated some memory cells

Bade-ji - I didn't express myself too well, I had assumed that ISRO (based on their comments) wanted empircal data on the planetary gravitational effects to augment their theoretical assumptions. my question was more like - what is the need if this is well known already?

point taken about sexiness of space research to keep geekbhais happy, but at the end of the day, space has to pay for itself

[prao]

Lalmohan: The Chandrayaan spacecraft is on a perfect Hohmann transfer orbit to the moon so S shape is very bad energetically. Google Hohmann transfer and find out what it is. It is energetically the most efficient orbit for obvious reasons. However it takes the longest possible time. I was very happy to see that the energetically efficient orbit was selected.

and from he Hindu ..

The engine fired for about nine-and-a-half minutes from 7.08 a.m. on Sunday. This successful firing lifted the spacecraft’s orbit from an apogee of 74,715 km and a perigee of 336 km on Saturday to its present apogee of 1.64 lakh km and a perigee of 348 km. The spacecraft has almost reached half the distance to the moon, which is 3,84,000 km away from the earth. In this orbit, Chandrayaan-1 takes about 73 hours to go round the earth once.

vsunderji - a question for you, if you'd be so kind:
It looks like the firing of the LAM is not only increasing the apogee as it should but also the perigee (336 to 348 km). If the engine is fired at perigee as I think it normally should be, would that not only increase the apogee?

[samuel]

Vsunder,

I am wondering if earth-sun-sat-moon system is ever of interest either as a unified system, or decoupled into two interacting systems. But it seems to me the more stationary points you have, the easier it might be to develop low energy budget orbital transfers. Take this as a question from someone who knows chaotic and nonlinear dynamics, but not celestial mechanics.

Also, is there any realtime or near-realtime prediction and control in trajectory planning in this application, i.e. do you ever need to ingest observational data and re-simulate as the mission progresses or is this all bang-bang control?

S

[JaiS]

A few research papers, apologies if these have been posted here before.

MINI-SAR: AN IMAGING RADAR FOR THE CHANDRAYAAN 1 MISSION TO THE MOON from "Lunar and Planetary Science"

Chandrayaan Mission Objectives and future lunar programs


India begins Chandrayaan-2 work

Following the successful launch of India's first lunar orbiter Chandrayaan-1 on 22 October the Indian Space Research Organisation is preparing for its second Moon probe, the Rp4.2 billion ($84 million) lander/rover mission Chandrayaan-2.

This mission is a joint venture with Russia scheduled for 2011-12. It will use the three-stage ISRO Geosynchronous Satellite Launch Vehicle with a cryogenic upper stage to send Chandrayaan-2's lander and rover to the Moon's surface. Russia is to provide the rover.

"We are looking at having a soft landing for Chandrayaan-2 instead of a hard landing. We should be working on technologies that will be part of the proposed Moon base. If we are to become a developed country by 2020, it will be crucial for us to develop such technologies," says ISRO's Chandrayaan-1 project director, M Annadurai, referring to the proposed international lunar outpost expected in the 2020s.

Chandrayaan-2's rover will use a robotic arm to collect samples and conduct in situ analysis of the Moon's soil. Chandrayaan-1 passed the 150,000km (93,000 miles) mark from Earth on 26 October. After its launch ISRO's Vikram Sarabhai Space Centre's projects director S Ramakrishnan said that Mars probe studies have started and that the GSLV could put a 1,000kg (2,200lb) spacecraft into Martian orbit.

[Bade]

Bade-ji - I didn't express myself too well, I had assumed that ISRO (based on their comments) wanted empircal data on the planetary gravitational effects to augment their theoretical assumptions. my question was more like - what is the need if this is well known already?

I would hazard a guess that it was to calibrate ISRO's tracking systems in real time. Any calibration methodology is incremental information gathering in the absence of absolute measurements.

[John Snow]

Bade saab absolutely on dot, also this is the best time to delta between comparator values , caliberated values etc

[Bade]

It looks like the firing of the LAM is not only increasing the apogee as it should but also the perigee (336 to 348 km). If the engine is fired at perigee as I think it normally should be, would that not only increase the apogee?

Perigee is a 'point' on the elliptical orbit, the engine was firing away for 9 minutes or so right ? The satellite must have moved a considerable distance beyond this 'point' during this firing. This will naturally lead to the idea of a dynamic perigee, won't it for all practical purposes increase the perigee, but will never decrease it with each impulse given.

To take a geometric view of the situation, draw a half-circle touching the perigee of the elliptical orbit. Any instantaneous engine firing will move the object at perigee to the space out of the circle. This automatically implies a larger distance from the reference center of the circle drawn or the foci of the elliptical orbit. A cumulative sequence of firings will leave the perigee growing in value.

If you could have given an instantaneous impulse at the perigee point rather than over the 9 minutes, then and only then can you have preserved the original perigee value.

[SSridhar]

I had assumed that ISRO (based on their comments) wanted empircal data on the planetary gravitational effects to augment their theoretical assumptions. my question was more like - what is the need if this is well known already?

There are several methods to reach the moon. Hohmann Transfer is one of them, which is what ISRO has chosen for Chandrayaan. Again, ISRO has chosen GTO to be the orbit from which to repeatedly raise the apogee rather than an from an LEO, for reasons of energy efficiency as the launch vehicle itself would have imparted a higher energy so that the fuel budget for the spacecraft is correspondingly less. In this GTO, Chandrayaan-I was inserted into an elliptical 255 x 22,860 orbit at an inclination of 18 deg. The apogee has been constantly raised. Once it went into deep space, the effects of the sun and the moon on the orbit becomes significant. It becomes a 4-body problem of Sun-Earth-Moon-Chandrayaan-I. For different orbits, the effects are different and this problem needs empirical solution because of the infinite possibilities. The orbits of the Americans, Russians, Japanese and Chines have been different before. They have also employed varying techniques of transfer, some of them a direct transfer and some of them exotic techniques. This is also a reason that ISRO has introduced two more intermediate orbits in order to be quite precise.

[vavinash]

http://www.chandrayaan-i.com/chandrayaan2/index2.html
http://www.chandrayaan-i.com/chandrayaan2/how2.html

Nice details of chandrayaan-2.

[lakshmikanth]

Looks like the babooze dont like a manned space mission:

http://www.indianexpress.com/news/upa-m ... an/378611/

[vavinash]

The next govt can give the permission by around 2010. I wouldn't worry too much about it.

[hnair]

So a lameduck govt can sign a politically divisive deal with an external power, but cannot find enough political consensus on the one thing that any average Indian taxpayer would gladly support?

Where is Amar Singh when we need him.

Anyways, I think it is early stages and they have already sanctioned the necessary moolah to keep the pot boiling. In India, all these programs needs an element of stealth, thanks to the bevy of Outlook/Frontline writers.