Bharat Rakshak

SSSalvi

Lander separated from orbiter.
There is media coverage of Chandrayaan-2 lander
Landing from 1:30 AM IST onwards on Sept 7 and Pragyan rover rolling out from the lander from 5:30 AM IST.

SSSalvi

^^ Of late, ISRO has started placing ( and also releasing the captured videos to public viewing ) cameras at inter-stage junctions so we surely can expect separation video ( mostly after sometime after the separation ..... they may not - and rightly so - want to publish certain intermediate steps ) ...

SSSalvi

CY2 can't give clean image right now. Camera calibration has to be done after it reaches its final orbit.

Absence of shadows in above images means this could be Radar image.

SSSalvi

The landing point ..( (-70.90267°, 22.7811°) (Bottom of the picture - slightly left from the middle) ---- That area looks so pockmarked with craters, it will be an immense feat to pull this landing off. It is due to the projection. Actually it is as pockmarked as the equatorial region butdue to the...

SSSalvi

^ Why double sideband? The data bandwidth is very small. So it is not a big problem because the frequency band is specifically allotted for this purpose. ( There is a international body which allocates frequencies for different purposes. E.g. 2G, 4G are internationally assigned for frequency and mod...

SSSalvi

Numerical data input used to generate one of the graphics that I post is based on jpl horizon .

SSSalvi

^
Why should there be no color on Moon? ( noob question .. not comment )

SSSalvi

I really hope that ISRO has got high definition cameras in the lander/rover. Does anyone know the specs of these cameras, their resolution? If it is DD like coverage/resolution of their launches, it will be a disaster. I know data transfer rates are the bottleneck for transmitting high resolution p...

SSSalvi

^ True But with continuous R&RR one can determine the variations in X,Y, Z co-ordinates. R&RR sessions last several hours if need be .. but at typically an hour or so. ==== Pre-answer to expected corollary After 21st Aug orbit Lowering : Orbit period is about 28 hours and after 28th it will ...

SSSalvi

^ To give simple analogy: In preliminary physics we had problem of Echo ... I receive echo after 1 second so what is the distance between me and the mountain? That gives distance in stationary situation. If you are moving then do the measurement continuously at equal intervals .. you will get the ob...

SSSalvi

how do they determine distance at such large distances esp when everything is moving? By dopppler shift measurement. It is an involved theory. At least l can't explain in simple terms. Regarding accuracy, in 1975 , with the then technology, which was contained in the size of 5 racks of 6 ft height ...

SSSalvi

@Rony If Earth orbit was polar, then C2 would have traveled northwards or southwards whereas the moon is in almost equatorial orbit. So initial orbit was near to ecliptic but slightly adjusted to match the intended LOI point taking into consideration the liberation of moon orbit. ---- Final descent ...

SSSalvi

The trailer video did show the methodology. But the
recent briefing gives more numbers.

SSSalvi

Just a guess: there could be fine adjustment protruding pins on each leg to stabilize. A few years ago an ESA spacecraft which was on a unique mission of landing on a comet head met such a catastrophe when it tipped and fell in a trench killing the mission. I am sure that ISRO would have learnt a le...

SSSalvi

Continuing Chandrayaan 2 ( CH2 ) orbit details along with other other objects : First a general view of a combination of Earth, Moon and CH2 orbits(after 5th ORM ) depicting 1. What would have been the undisturbed orbit if TLI was not done 2. Post TLI new orbit carrying CH2 from Earth's Gravity to L...

SSSalvi

^^^
Perigee is near SouthAmerica and North America join.
Aug 13 around 2105 UT

SSSalvi

^ Did they? Did not know it .. interesting ... will try to see.
Thanks for the info.

SSSalvi

^^^
What can they show for TLI and LOI? It is only sending of commands.

They might perhaps show Landing if they want to. Even there they might want to keep initial images classified.

BTW, Now the operations are not from SHAR .. they may be from ISTRAC/Peenya/Bayyalu.

SSSalvi

Just enjoy!.. No scientific value. We are used to see the 2 dimensional images of Chandrayaan 2 orbits .. e.g. https://oi50.photobucket.com/albums/f314/sam0403/CH2%20Orbits%20flat_zpssj3js874.jpg But that is just half truth. When you include the motions of various objects ( as shown below ) in a tim...

SSSalvi

Some Facts related to Chandrayaan 2 orbit/orbit manuevers May be useful for any enthusiast. ( Compiled from various sources for my own personal use ) Table of Orbit Raising Manuevers (ORM ) while the Spacecraft is in Earth’s Gravitational sphere of Influence. ORM No. Date Time ( IST ) Firing Duratio...

SSSalvi

^^^
Ramana ji .. I am not offended.
It was really a wrong post ( actually a careless computation to attempt at finding numbers without proper care to convert all the units to similar system of units) .. scientifically the numbers have no meaning unless accompanied by units.

SSSalvi

^^^
^^^
My Apologies.. Sudarshan , for the post.

SSSalvi

^^^
M=7.35*10^22
GM=49000
R=1738+10
V= 5.3 km/sec

SSSalvi

There WILL always be better options which the experts may not have opted for. But for that there may be some other blockades .. like lack of technology for other feeder equipment equipment, cost/expertise to go in for the new tech etc. It is also possible that after putting in so much of effort in s...

SSSalvi

I can see the pictures. Ssalvi ji, are there parts of the moon in perpetual darkness? No ( At least to my knowledge. There could be some very small portion which is not illuminated anytime .. but not sure ). What is shown as bright area is mostly what is facing Earth.. Other side is not seen becaus...

SSSalvi

I can see the pictures. Ssalvi ji, are there parts of the moon in perpetual darkness? No ( At least to my knowledge. There could be some very small portion which is not illuminated anytime .. but not sure ). What is shown as bright area is mostly what is facing Earth.. Other side is not seen becaus...

SSSalvi

The LAST act decides the Beginning There have been several theories about the timing of Chandrayaan 2 Launch. From Neil Armstrong anniversary to 15th August celebrations in India. But the real reason is as follows. The Lander and the rover have to land at the specified location and .... The Locatio...

SSSalvi

^^^
Will post updated orbit images as and when the details are available in public domain to create those.

SSSalvi

Created 3 views of current orbit of Chandrayaan 2 . Whole orbit around Earth for comparing the relative sizes of Earth and Orbit ellipse. https://oi50.photobucket.com/albums/f314/sam0403/CH2%20A_zpst6xp6zki.png Orbit and also the Moon depicting the distance to be covered in the last maneuver to plac...

SSSalvi

Kakarat wrote:Can some one suggest me a free video editing software to edit the launch video for posting online

You Tube's own editor is good ... You can cut/move and give textual highlights.
Not very cumbersome to grasp the nitty gritties.

SSSalvi

Very very naive and stupid question, but its constantly bothering me, and I never knew any other place other than BRF to ask this. I know that the rover is planned for 14 earth days as this is the time its going to get enough sunlight. Is it possible that after another 15 days, its battery starts c...

SSSalvi

That is a nice catch Mort. 24 Meters ( 0.024 ) is the right value

SSSalvi

https://images.firstpost.com/wp-content/uploads/2019/07/Comparison-between-former-and-present-launch-sequence-_ISRO.jpg https://images.firstpost.com/wp-content/uploads/2019/07/Former-and-current-approach-plan-for-Chandrayaan-2_ISRO.jpg This is actually a nice timeline comparison between earlier att...

SSSalvi

https://timesofindia.indiatimes.com/india/chandrayaan-2-landing-likely-on-september-6-7-launch-on-july-22/articleshow/70283493.cms “Now, nothing in the initial approach is changing. We’ll still take 22 days to insert Chandrayaan-2 into the lunar orbit because we need 17 days around Earth for five o...

SSSalvi

Sorry for late reaction. There are some words like Jugaad, quickfix about ISRO's wording " Learning Curve". Should there not be a learning curve in every new attempt? In fact the safety gates in Launch sequence software did its job of aborting the flyoff because the designers had put appro...

SSSalvi

^^^ Care! Better rely only on ISRO updates ... otherwise conclusions drawn from half sentences create chaos. No such update from ISRO. One news source gives it more clearly “We will have to dismantle the rocket to get to the root of the problem… we have window till month end to launch the mission,” ...

SSSalvi

^^^ AS far as launches are concerned ISRO has mastered the Launch process ( evolved through SLV,PSLV, GSLV and so on) and the softwares have been foolproof in detecting glitches and reporting those during countdown period. Anyway there is no human involvement in the process so there can't be any 'to...

SSSalvi

^^^
Thanks SwamyJI ( Sorry, I played around your personal property.. Your Name )

SSSalvi

Some Numbers , if anyone is interested. Can't post the source link link because I have lost the link. :( Launch Sequence .. Graphical Representation and Tabulated. https://lh3.googleusercontent.com/XvSUMxfjtZfb_3kFto5-I31bBI-Dtc9lhDxjCyUj5wTvlo_nimU19ovxVPAYzdL1klq5CIVEyMp9Y4OE0rYysu1eCWH6zDSMr2dWVi...

SSSalvi

Each fragment has it's own apogee/perigee depending on it's orbit. I can draw each orbit but it causes a clutter in image. 95% have perigee of about 250 kms. 5 or 6 orbits have apogee of 1500 plus kms. Rest are mostly between 300 and 500 apogee. Will give a table of statistics in a day or two. Or re...

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