Chandrayan-1 moon mission

SwamyG · Post by **SwamyG** » 15 Nov 2008 03:48

What was extraordinary about the historic event of Chandrayaan-1’s probe landing on the moon on Friday night was that the spacecraft was built in India, it was put into orbit by the Indian rocket, PSLV-C11, and the launch took place from Indian soil, said a jubilant M. Annadurai, Project Director, Chandrayaan-1. Mr. Annadurai led the team that integrated the 11 scientific instruments, including the Moon Impact Probe (MIP) into the Chandrayaan-1 bus at the ISRO Satelllite Centre, Bangalore. The MIP was built by the Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram. “We have got all the data. We are working on the data and processing them,” Mr. Annadurai said.

SwamyG · Post by **SwamyG** » 15 Nov 2008 03:51

I believe that the moon cannot be left to a few countries.

Guess who said those words?

ramana · Post by **ramana** » 15 Nov 2008 04:03

SwamyG wrote:
I believe that the moon cannot be left to a few countries.
Guess who said those words?

While at it who authorised the CY-I mission? And When?

Muppalla · Post by **Muppalla** » 15 Nov 2008 04:08

ramana wrote:
SwamyG wrote: Guess who said those words?

While at it who authorised the CY-I mission? And When?

A.B. Vajpayee during Independence Day speech of 2003.

SwamyG · Post by **SwamyG** » 15 Nov 2008 04:13

The planned was hatched well before 2003, IIRC it was around 1999. Ramana garu are you asking from a political stand point?

SaiK · Post by **SaiK** » 15 Nov 2008 04:14

GoI. 2003.

BTW, ISRO should have completed received data transmitted from Chandrayaan-1. Is the satellite in synch with bylalu yet?

SwamyG · Post by **SwamyG** » 15 Nov 2008 04:19

Here is something to simply boil your blood. Now that we have done it, we can give some moo-thod jawab to others

vsudhir · Post by **vsudhir** » 15 Nov 2008 04:26

SwamyG wrote:Here is something to simply boil your blood. Now that we have done it, we can give some moo-thod jawab to others

That was a hoot. Save urself BP issues folx, read and laugh onlee.

The cowboys on that thread remind me of a genitelman guest on some BBC talk show aimed at Brit audiences who was 400% foaming at the mouth and musharraf when CY launched successfully..... The suckers' time is up and they are chicken-scared of admitting it.

Like some wise man said: "The dogs bark but the caravan moves on".

Amber G. · Post by **Amber G.** » 15 Nov 2008 04:31

All - Great pictures. Thanks.
Shalav –

Shalav wrote:
Please read my post, and many (including some scientists) make mistake here, but the figure has NO "corkscrew" or even "waves" as you pointed out. The orbit at every point is convex. (This is true, of course for earth/moon system , and not any general orbiting body)
Did not mention anything about waves, just the corkscrew orbit.

However, be that as it may, locally, the Moons orbit does seem to corkscrew around the Earths orbit of the Sun. How that orbit looks from the the sun is immaterial. It is a complex orbit locally, and twice year it is occluded during lunar eclipses.

Hence there are 2 observations

a. The orbit is a complex orbit - ie it is not a simple planar orbit - this is what I thought we were discussing.

b. That makes a sun-sync. orbit difficult if not impossible.

I can’t understand exactly what you are trying to say. Hope a little orbit understanding may be useful to aam-janata hence my point was:

There are no “cork screws” in moon orbits whether you look “locally’ or from sun. More specifically the figures and specification you gave in your previous post:

2. A corkscrew line wrapped around the Earths orbit depicting the moons orbit as it circles the Earths orbit.

see this image for a top-down 2D view

http://www.astronomyforbeginners.com/im ... -e-m-s.jpg

add on the ~5 deg. inclination and you can imagine the corkscrew - see below for a depiction in Gravity Simulator

http://www.jasondoucette.com/games/grav7l.gif
The blue lines are a good approximation of the Earth / Moon orbital relationship as they circle the Sun

It is, to put it mildly, not accurate -(Though many, who are not familiar with actual orbits make similar mistake) Main point here is there are no loops, no backward motion, and curvature is always towards the sun. (Blue line is NO WHERE near a “good approximation” ) (See my previous post and reference given there .. or any good book on celestial mechanics)

If you want to see “local perspective”..

From earth – moon’s orbit is ellipse (pretty close to circle), it is tilted ( BTW not 5 degree but about 27 degrees (varies between 18 to 28 degree) to celestial equator. – (plane of earth’s equator) (The nodes precess at the rate of 18-19 years for a rotation)

Sure “complexity:, I guess, is in the eye of the beholder, as there are small perturbations but one will not go wrong and get pretty accurate value of moon’s positions by considering it a simple elliptical planar orbit.

From Sun – see my previous message. – One adds earth’s motion (again elliptical orbit) ..but again surprising part may be there are no cork-screws etc.. the orbit of moon is also fairly close to an ellipse around the sun.

Hope this helps.

(I think reference of "sun-synchronous" with respect to CY-I is ddm's doing .. it does not make much sense why one would like to have such an orbit for moon orbiter (and by sun-synchronous I mean the nodal points of the orbit precess at the rate of 1 per year) - but if one wanted to have it (It might be a good exercise for classical mechanics student) critical factors would be, I think, buldge/shape of moon and inclination of the orbit of CY-1 with respect to moon's equator , and how high one wants the orbit to be)

vdutta · Post by **vdutta** » 15 Nov 2008 04:43

some pics...

The scientists of Indian Space Research Organisation (ISRO) checks the data at the Mission Operation Control Room at the ISRO center in Bangalore on November 14, 2008. An Indian probe landed on the moon on November 14, the Indian Space Research Organisation announced, in a milestone for the country's 45-year-old space programme. AFP PHOTO/Dibyangshu SARKAR (Photo credit should read DIBYANGSHU SARKAR/AFP/Getty Images)

The scientists of Indian Space Research Organisation (ISRO) check the data at the Mission Operation Control Room at the ISRO center in Bangalore on November 14, 2008. An Indian probe landed on the moon on November 14, the Indian Space Research Organisation announced, in a milestone for the country's 45-year-old space programme. AFP PHOTO/Dibyangshu SARKAR (Photo credit should read DIBYANGSHU SARKAR/AFP/Getty Images)

The chairman of Indian Space Research Organisation (ISRO) Madhavan Nair (L) gifts a moon model to former president of India A.P.J. Abdul Kalam (R) during a conference at the ISRO center in Bangalore on November 14, 2008. An Indian probe landed on the moon on November 14, the Indian Space Research Organisation announced, in a milestone for the country's 45-year-old space programme. AFP PHOTO/Dibyangshu SARKAR (Photo credit should read DIBYANGSHU SARKAR/AFP/Getty Images)

hnair · Post by **hnair** » 15 Nov 2008 04:49

SwamyG wrote:Here is something to simply boil your blood. Now that we have done it, we can give some moo-thod jawab to others

geez....who hangs around such lonely places other than Mark Foley or Larry Craig? Ask them which John Deere cap they are planning to wear for Obama inauguration.

shaardula · Post by **shaardula** » 15 Nov 2008 04:53

request to admins. please dont trash this thread. please.

hnair · Post by **hnair** » 15 Nov 2008 05:00

harbans wrote:
Scientist calls for co-op between Asian space powers

BEIJING—A Chinese scientist on Wednesday called for moon probe program experts in China, India and Japan to step up cooperation to "deepen mankind's understanding of the moon."
Ouyang Ziyuan, chief scientist for China's moon exploration program, said the three countries shared goals on moon probe while each had its advantages.
—Xinhua
http://dailymailnews.com/200811/14/news ... tch06.html

Score..Chang'e 1 year: Released 1 moon picture. (Controversial, possible photoshopped copy of an earlier Apollo one); CY-1: 1 day in 100km orbit..2 pics released within 3 hours of MIP impact. Total: 3 Moon pics.

Go ISRO GO!

right, so that they can steal Chandrayaan's and Kayuga's tech and make something similar out of glue, macaroni and melamine

Wonder what sort of bandwidth the Chang'e had to download such huge amounts of data? I think some scientist from China, while on a visit to US must have sneaked back one of those install CDs that AOL used to spam US mailboxes with in the late 90s. Probably been honored for this achievement by AQKhan Academy of Sciences, Beijing.

Raj · Post by **Raj** » 15 Nov 2008 05:03

Congrats to ISRO.

A question:

I thought the descent would be video-graphed and sent to the orbiter, to be later transmitted to the command center. Is it photographed or video-graphed? Does anyone know?

vdutta · Post by **vdutta** » 15 Nov 2008 05:08

it is video graphed as for as i know. it is video graphed both by MIP and CY.
cant wait to see those videos, that will be best 25 minute video i will ever watch..

Raj · Post by **Raj** » 15 Nov 2008 05:13

vdutta wrote:it is video graphed as for as i know. it is video graphed both by MIP and CY.
cant wait to see those videos, that will be best 25 minute video i will ever watch..

Sounds great

shaardula · Post by **shaardula** » 15 Nov 2008 05:19

hnair wrote: right, so that they can steal Chandrayaan's and Kayuga's tech and make something similar out of glue, macaroni and melamine

Wonder what sort of bandwidth the Chang'e had to download such huge amounts of data? I think some scientist from China, while on a visit to US must have sneaked back one of those install CDs that AOL used to spam US mailboxes with in the late 90s. Probably been honored for this achievement by AQKhan Academy of Sciences, Beijing.

riot only saar you are.

Gerard · Post by **Gerard** » 15 Nov 2008 06:15

Breakneck suicide dive gifts India a ‘beautiful’ moon

Scientists said the MIP, or the impactor, would have struck the ground at a speed of more than 1.5km per second (5,400kmph), and the ferocity of the impact would have left only shards of metal and its electronic innards scattered on the lunar landscape.

The impactor had the Indian flag painted on its sides. A senior Isro scientist said he would not speculate on the final condition of the impactor or the flags. “Imagine what will happen when something crashes at more than 5,000km per hour,” the scientist said.

“Its job is over,” the scientist said.

vsudhir · Post by **vsudhir** » 15 Nov 2008 06:24

Posting in full from the Pioneer.

Vajpayee vision now a reality

It is like a dream come true for former Prime Minister Atal Bihari Vajpayee, the living legend of Indian politics. It was on the nation’s 56th Independence Day celebration in 2003 that Vajpayee had announced from the historic Red Fort: “Our country is now ready to fly high in the field of science. I am pleased to announce that India will send her own spacecraft to Moon by 2008. It is being named Chandrayaan-1”. In Sanskrit, “Chandrayaan” means “Moon Craft”.

Vajpayee has every reason to be pleased. The BJP patriarch noted with great pleasure the successful launch of India’s first unmanned mission to Moon. “I offer my hearty congratulations to Madhavan Nair, chairman of ISRO, and other scientists and engineers working on this mission on this historic success. They have worked relentlessly and with commendable fortitude to place an Indian spacecraft, carrying the Tricolour, on the trajectory of Moon,” Vajpayee said last month.

The former PM said he was especially pleased that this project, which was planned by the NDA Government, had been brought to a successful fruition. “I had the honour of announcing it in my Independence Day address to the nation in 2003,” he recalled.

In his words, the mission to Moon was a stupendous achievement by India in the frontier area of space research. Moreover, he outlined, what was especially creditable is that “our achievement is the fruit of self-reliant efforts”.

“I am sure that, other than the scientific knowledge that Chandrayaan-1 will garner, it will serve as a beacon of inspiration to the younger generation and as a stepping stone to other great feats by India in science and technology,” he said.

Arun_S · Post by **Arun_S** » 15 Nov 2008 06:58

I love this picture.
Masterminds: Chairman of Isro Madhavan Nair with A P J Abdul Kalam in Bangalore on Friday. (AFP Photo)

vdutta wrote:

The chairman of Indian Space Research Organisation (ISRO) Madhavan Nair (L) gifts a moon model to former president of India A.P.J. Abdul Kalam (R) during a conference at the ISRO center in Bangalore on November 14, 2008. An Indian probe landed on the moon on November 14, the Indian Space Research Organisation announced, in a milestone for the country's 45-year-old space programme. AFP PHOTO/Dibyangshu SARKAR (Photo credit should read DIBYANGSHU SARKAR/AFP/Getty Images)

And here is the news on the inspiration and driving force behind the Chandrayaan and Moon-Impact-Probe: Prof APJ Kalam.

Mission Moon: Kalam’s brainchild lands succesfully

15 Nov 2008, 0257 hrs IST, Srinivas Laxman, TNN
MUMBAI: Former president APJ Abdul Kalam, who first suggested the inclusion of Moon Impact Probe in the Chandrayaan mission, said the landing of the probe on the lunar surface proves India’s superior technology.

Kalam, a rocket scientist, put forward the idea during the International Lunar Exploration Working Group Conference at Udaipur in November 2004.

Kalam told TOI: ‘‘After (the spacecraft) going so near the moon, I felt the mission will have more scientific relevance if the probe was included. I believe that the moon cannot be left to a few countries.

I strongly felt that India cannot be left behind. So, I suggested the probe, and many in ISRO enthusiastically supported the plan.’’

‘‘The landing of the probe establishes India’s presence on the moon and prove that India can do it,’’ Kalam said.

According to him, the probe will help in studying the moon’s geological features. ‘‘I visualise that in another four decades, the earth, moon and Mars will have economic and strategic importance. Well, my feeling is the way we have taken Chandrayaan and flown 3,80,000 km clicking a beautiful picture of the earth and putting it into the lunar orbit on November 8 is impressive. November 8 is, therefore, a very important day for us.’’

Strategic expert K Subrahmanyam said the landing placed India on par with powerful space powers like the US and Russia.‘‘It has some political significance because our Indian flag is on the moon. Apart from the political importance, it is also a great technological achievement for India.’’

SaiK · Post by **SaiK** » 15 Nov 2008 07:29

here is what exactly happened.. per hindu link

“After it is separated, the MIP starts spinning like a top. The aim behind spinning it like a top is to give directional stability to the MIP just like a top is stable when it is spinning,” explained B.R. Guruprasad, Public Relations Officer, ISRO. Then, the MIP’s retro-rockets were fired to reduce the speed of its descent. When the velocity was reduced, it followed a curved path towards the surface of the Moon, Mr. Guruprasad said. The MIP descended for about 25 minutes from its separation till it impacted on the Moon.

So, we can expect 25 minutes of videos and picture shots!~ cool.

--

The Shackleton crater has an undulating terrain with hills and valleys. Since the valleys are in the Moon’s permanently shadowed regions, it could harbour water ice. The dust kicked up when the MIP crashed would be analysed to check whether it contained water ice. The probe died within a few seconds of its crash.

Singha · Post by **Singha** » 15 Nov 2008 07:54

Kalam sir has a strategic mindset. when the time comes to frame "rules" on how to rape the
moon for fresh resources, the rulemakers will be only those on the high ground and well armed.

it pays to plant our flag and keep a sharp eye on activities on all fronts.

SaiK · Post by **SaiK** » 15 Nov 2008 08:14

Everything depends on the chemical analyzer. Should it find what is needed for the fusions, then see how the race begins.. we have to be very careful what the analyzer reports.. it should be top secret mission. We have already seen how Russia goes under the oceans and plants flags.

Arun_S · Post by **Arun_S** » 15 Nov 2008 11:40

Indian Probe Impacts Moon: SpaceDaily

by Staff Writers
Bangalore, India (AFP) Nov 14, 2008
An Indian probe landed on the moon on Friday, the Indian Space Research Organisation announced, in a milestone for the country's 45-year-old space programme.

The probe touched down on the moon at 8:34pm (1504 GMT), 25 minutes after it was ejected from an unmanned spacecraft orbiting the moon, spokesman S. Satish said.

"During its descent from Chandrayaan-1 an onboard video camera transmitted lunar pictures to the ISRO command centre," Satish said in the southern Indian city of Bangalore where the national space agency is headquartered.

Scientists monitoring the probe cheered as ISRO chairman Madhavan Nair announced the success of the country's first lunar mission, which began on October 22 when a rocket transported Chandrayaan-1 into space.

The probe, carrying three instruments and with the Indian flag painted on its outer panes, settled in a crater in the moon's south pole.

Nair said the landing was perfect.

"We have now successfully put our national flag on the lunar surface," he told a news conference.

"The moon has been very favourable to us and this is a very productive and fruitful mission," he said, and added: "We have also emerged as a low-cost travel agency to space," referring to the mission's 80-million dollar tag.

Chandrayaan-1 is on a two-year orbital mission to provide a detailed map of the mineral, chemical and topographical characteristics of the moon's surface.

Buoyed by its success, ISRO plans to send a second unmanned spacecraft to the moon in 2012 and separately launch satellites to study Mars and Venus.

India started its space programme in 1963, developing its own satellites and launch vehicles to reduce dependence on overseas agencies.

It first staked its case for a share of the commercial launch market by sending an Italian satellite into orbit in April last year. In January, it launched an Israeli spy satellite.

India is also hoping the mission will boost its space programme into the same league as regional powerhouses Japan and China.

As well as looking to grab a larger slice of the global commercial satellite launch market, India, Japan and China also see their space programmes as an important symbol of their international stature and economic development.

But India still has a long way to go to catch up with China which, together with the United States, Russia and the European Space Agency, is already well established in the commercial launch sector.

China's immediate goal is the establishment of a space lab, with Beijing's long-term ambition to develop a rival to the International Space Station, a project involving the US, Russia, Japan, Canada and some European countries.

Japan has also been boosting its space programme and has set a goal of sending an astronaut to the moon by 2020.

Japan's first lunar probe, Kaguya, was successfully launched in September last year, releasing two baby satellites to study lunar gravity and other projects.

SSSalvi · Post by **SSSalvi** » 15 Nov 2008 12:47

SSSalvi wrote:
UPrabhu wrote:If ISRO guys visit this site, please don't keep your "ANNADAATAA" .. the taxpayers in dark... we will happily foot the bill for future missions.. but keep us aam juntaa in the loop.. not a single picture released after LOI
I ( as an ex-isro ), have requested today to ISRO website that now ISRO is being watched by the people around the whole world so please update the website continuously. ( Today the website says : Last update on 12th Nov ) .

Infact after writing that email I stumbled on your post.

Please help O God!

Whether my request or otherwise - Thanks ISRO for website updates even at 11:55PM ( Of course for ISRO day or night should not matter. Events decide the working hours not other way round )

juvva · Post by **juvva** » 15 Nov 2008 13:37

SaiK wrote:Waiting!...

Saik

Nice pic, any chance of a full sized wallpaper image? Thanks

vina · Post by **vina** » 15 Nov 2008 15:38

Bhailog. Is the Chini Khujli because while they got to Lunar orbit earlier, the Injuns actually upstaged them by planting their flag on lunar soil ? . History will always record first 4 as USSR, US, Japan and india.. The first moon landing by the Chinese is in the Change'3 mission, which seems quite far away.

Maybe , they really didnt think that the Indians could go to the moon in the first place.

Singha · Post by **Singha** » 15 Nov 2008 15:56

its actually a bit unclear what is the current condition of Chang'e and if all its payloads are working properly. their culture of hiding failure + Chang'e carrying no foreign payloads makes the program opaque, even though they promised to share data.

is the ESA getting regular data from Chang'e ? ESA helped them out with ground monitoring
station support.

VRao · Post by **VRao** » 15 Nov 2008 16:11

This image shows a closer view of the moon's surface taken by Moon Impact Probe on Friday, Nov. 14, 2008 as it approached it after separating from India's Chandrayaan-1 spacecraft. The first lunar probe from India landed successfully on the moon Friday as part of a two-year mission aimed at laying the groundwork for further Indian space expeditions, the ISRO said. (Pic:Indian Space Research Organization, HO)

Source: http://www.chandrayaan.bharatchronicle.com

narayana · Post by **narayana** » 15 Nov 2008 18:18

Saw on TV Yesterday Fmr President Kalam has said in the manned Moon mission in 2020 Indians on Moon May find "New Very Important Things" .may be he is implying the existence of UFO's Moon Base made public by Indians.

SSridhar · Post by **SSridhar** » 15 Nov 2008 18:20

CY-I validates our assumptions - Shri Madhavan Nair

The successful landing of the Moon Impact Probe on the lunar surface has not only boosted the confidence of ISRO to undertake inter-planetary travel in future, but also conveyed a firm message to the world that India means business in the field of space, ISRO chief G Madhavan Nair said here today.

"It (the landing of the Moon Impact Probe (MIP) and the Chandrayaan-1 mission) has validated many of our assumptions and many of the principles involved in interplanetary travel. It's really a big boon for ISRO. We can now take up travel to any other planet with confidence," a jubilant Nair told PTI in an interview, a day after the historic event.

France & EU congratulate India

"France, on behalf of the European Union, warmly congratulates India for the successful landing of the Moon Impact Probe and the launch of the lunar exploration programme," a statement issued by the French Embassy said.

France is the current chair of the 27-nation European Union.

"This remarkable success of the Indian space vehicle confirms anew India's eminent position among the world-class scientific and technological powers," the statement said.

It said France and the European Union "look forward to the strengthening of the existing scientific cooperations with India in the field of space, which are particularly promiseful for the development of science and knowledge worldwide."

SwamyG · Post by **SwamyG** » 15 Nov 2008 18:31

Chandrayaan project an investment for future: Kasturirangan The leadership must have some serious plan up their sleeves. Human settlements in moon? Very nice onlee.

Bhailog, how is the sentiment over in the desh? Is the aam admi on the street gaga over this, or this still playing only on "select theaters"? Is the doodhwala talking about this?

sumishi · Post by **sumishi** » 15 Nov 2008 18:32

narayana wrote:Saw on TV Yesterday Fmr President Kalam has said in the manned Moon mission in 2020 Indians on Moon May find "New Very Important Things" .may be he is implying the existence of UFO's Moon Base made public by Indians.

Beware! You are venturing into areas where angels fear to tread in this forum. I happen to know, trust me -- I am the fallen angel !!

juvva · Post by **juvva** » 15 Nov 2008 18:56

Hi Q launch video:

http://www.youtube.com/watch?v=WaMLYBoyQNk&eurl

enjoy!

Lalmohan · Post by **Lalmohan** » 15 Nov 2008 19:00

sumishi wrote:
narayana wrote:Saw on TV Yesterday Fmr President Kalam has said in the manned Moon mission in 2020 Indians on Moon May find "New Very Important Things" .may be he is implying the existence of UFO's Moon Base made public by Indians.
Beware! You are venturing into areas where angels fear to tread in this forum. I happen to know, trust me -- I am the fallen angel !!

sumishi - do you have an elongated skull made of crystalline material by any chance?

Abhijit N · Post by **Abhijit N** » 15 Nov 2008 19:08

Bhailog, how is the sentiment over in the desh? Is the aam admi on the street gaga over this, or this still playing only on "select theaters".

Sadly the aam janta hardly knows much...I was showing the images to some of mah friends yesterday and they were asking me...oh! so how many guys landed ?!!!

Is the doodhwala talking about this?

In your dreams!!!.....he is really too busy after roti, kapra & makan

A Sharma · Post by **A Sharma** » 15 Nov 2008 19:48

KARVACHOTH will not be same anymore

vsunder · Post by **vsunder** » 15 Nov 2008 21:48

This is an excellent paper that answers all the questions about "sun-synchronicity" on the Moon and how
ISRO proposes to handle it.

http://www.springerlink.com/content/260l2310k85350pw/

The next paper outlines a very clever idea of Del Bruno that was used for Hiten. By the way Samuel it answers your questions in part of de-coupling in a 4 body problem. Basically you cant but only under some assumption as the authors do.
Such passageways and "tunnels" exist between various heavenly bodies and should be exploited as a low cost way of getting from one to another.
What I am saying is that the Hohmann transfer is a low energy way to get us to the Moon in a Keplerian framework
of a Moon-Earth system. What Del Bruno found is that in a Moon-Earth-Sun system there are even more energetically
favorable ways to getting to the Moon; more energetically favorable than even the Hohmann transfer. This was used for Hiten. It uses the Lagrange points of the Earth-Sun system. The graphics in the paper are excellent. Note the stable periodic orbit around L1 the black circle and the unstable orbit through L1. Chandrayaan must have taken that path
before firing rockets.
Off course Hohmann is tried, tested and a very conservative approach and a good idea in a first attempt.
Del Bruno has a nice book on all this in Princeton University Press series.

http://www.cds.caltech.edu/~koon/resear ... y/koon.pdf

By the way Chandrayaan's orbit around the Moon is more or less fixed at 95 degrees inclination since my previous post
and the VSSC paper linked therein indicates such an orbit will have maximal orbital stability of >2 years. So imaging
will be done with this constraint. One should read the two papers, the one linked earlier by me on orbital stability
and the one linked above of ISRO on imaging in tandem. Both questions are tied isnt it?

sumishi · Post by **sumishi** » 15 Nov 2008 21:52

Lalmohan wrote:
sumishi wrote: Beware! You are venturing into areas where angels fear to tread in this forum. I happen to know, trust me -- I am the fallen angel !!
sumishi - do you have an elongated skull made of crystalline material by any chance?

There you go again!

Nefertiti is my distant ancestor!!

SSSalvi · Post by **SSSalvi** » 15 Nov 2008 22:00

Don't know if it is relevent/useful.

There is some discussion about Sun-Synchronous orbit. Just some loud thinking on that.

To understand Sun-Synchronous orbit around Moon one should get out of Earth and look down from above the Earth's orbit around Sun.

The figure shows Earth's orbit ( Red line ) over the period of a Lunar month. ( for simplicity say 28 days period ... so each position is seperated by 7 days )

Always same face of Moon is oriented towards Earth ( indicated with a small dot over Moon's sphere as it rotates around Earth )

The Sun-Synchronous satellite orbit is shown as a blue ellipse. Notice that it makes a constant angle with Sun's rays shown as parellel arrows near the bottom of image.

So the orbit should cover the entire moon in one Lunar Month. ( about 29 days )

For simplicity the Sun's rays are shown parellel but actually it should make about 30 deg angle over a month ( 360 deg rotation / 12 months ).

By incorporating all these corrections we can compute the rate at which the ellipse of satellite should rotate around moon ( Omega dot ) for Sun - Synchronization.