Bharat Rakshak

prao

I was thinking about the connectors some more and I realized that a seal like O-rings wouldn't be possible because it would make it difficult to connect the two halves together (the air inside would be resist compression). So a modified version of my theory is that after the halves were joined, the ...

prao

Ramana, I understand the mechanism. I am suggesting that the two halves of the joint enclose sufficient volume of air and form a tight enough seal. Tight enough that there is sufficient pressure force pushing them apart when the rocket reaches some altitude. Volume should be sufficient so that leaka...

prao

Here's some wild speculation about why the connectors separated: Pretty improbable I think but still who knows, worse mistakes have been made. What if the connectors chosen were: (1) new design - not flown before. (2) Did not have a positive lock (quite likely because they have to separate) (3) The ...

prao

An afterthought: ... If multiple connectors have snapped then it could be due to a rogue command impulse issued to their separation mechanism also. ... Regarding Self destruct command: A colleague who participated in assembly/evaluation of rockets at SHAR had told me that destruct command pulls a t...

prao

I'm not the mole says Arunachalam.

Now what did Nixon say? He said "I'm not a crook".

prao

I think I've been very clear about my opinion of the CY1 issue and why I think it's important. I'm sorry to say that some of you are missing the point and are addressing non-issues. If the causes of CY1's issues and early demise had been a purely technical issue, I would not have been so bothered. S...

prao

I think I've made it very clear that I consider CY1 a great achievement. Please read what I've said carefully.

Failures need analysis and you need to learn lessons from them. Closing your eyes to them only invites more failures.

prao

I hope this was not posted here before. I couldn't find it in the past few pages. Info about Santhanam by B. Raman in his inimitable point by point style with some interesting if uncomfortable questions for Santhanam. I've reproduced the full item here because it's all of great direct relevance to t...

prao

I do understand your point. my question was how can we be sure it is more than just an educated guess ? has ISRO said anything of the kind ? just curious. It is an educated guess, no doubt. And no it hasn't and I suspect that it won't since it may show them in poor light. I think what happened is t...

prao

The reason for the congestion of course is the MIP that was a late stage addition. the MIP was ejected almost as soon as CY-1 reached the moon. why do you think it continued to contribute to the heating problems via congestion ? what could have been the residual instruments left behind by it that w...

prao

From the Indian Express article: In fact, the decision to carry 11 payloads on Chandrayaan- I and whether it affected its thermal management is being actively debated. Scientists feel that had the spacecraft been less congested internal heat could have been more effectively ventilated. The reason fo...

prao

Here's a good one. The Chinese are up to their usual games of (trying to) lulling the Indian side to complacency. This time their tactic is simply to get GOI to stop HH The Dalai Lama's trip to Arunachal Pradesh and muzzle the new found voice of the Indian media. The idea being to get the MEA to thi...

prao

A clear eyed analysis means that childish emotional/jingoistic outbursts have no place in the discussion. Throwing out a list of questions, creating straw men and calling the fine engineers of ISRO names are only childish attempts at stymieing open discussion about the topic. The reason for analysis...

prao

Returning to my earlier observation of ISRO protesting too much. I would like answers to two basic questions with regard to CY1: 1. Why did ISRO underestimate the radiation/thermal load at the design orbit of 100 km? Was it a lack of available information? (I'd think that with so many missions to th...

prao

Now we hear of a " China Study Group " - a bunch of bureaucrats that's been putting restrictions on the army for a while by the looks of it. Restrictions of this kind only serve to weaken our claim on the border areas - quite simply if you don't assert ownership - by regular patrols, your ...

prao

I am really puzzled that ISRO has felt the need to recruit all and sundry to proclaim that CY1 was a 95% success. Has there been a backlash against ISRO after the CY1 mission was called off? I can't recall coming across anything on the web (no I didn't go looking for it - I dare say I could find it ...

prao

This doesn't make sense to me. How do you replace something as crucial as a bus management unit at such short notice - that too on a spacecraft waiting to be integrated to the launch vehicle? Anything put on a spacecraft needs to be individually qualified which isn't a quick process. The failure of ...

prao

Admiral Mehta's motivation could be to galvanize public opinion in favor of building up India's military, space and cyberwar capability and hopefully cause a little strengthening of the spine of the civilian leadership. It will do India's public a little good, this little shocker. I think people rem...

prao

There is nothing "disrespectful" in Sanjay M's discourse. Such a questioning attitude is quite useful in the forum. Not only is it "useful" but it is absolutely necessary for the integrity of the forum. There can be no restrictions or rules, either written or unwritten, on what ...

prao

For orbital/fuel consumption etc calculation, simple calculation (using Newton's Mechanics) can give the rough amount of delt-V, energy (fuel -consumption etc needed) - basically energy of an (elliptic - stable) orbit depends on its semi-major axis -only- and if you need to calculate the change in ...

prao

The theoretical resolving power of an optical system is not really relevant to CY1 with regards to orbital changes, no? The thermal issue has to do with thermal radiation from the moon not the sun. Do you have any lunar radiation numbers that might tell us how it will increase at lower orbits? I thi...

prao

How about an asteroid intercept if one is around? That should be exciting no? If requirements are reasonable (1st calculation to perform - 440 N? thrust, fuel specific impulse, available fuel ..?) all sorts of things can be tried.

prao

Something half as far away will appear twice as big. A 5 m object that was one pixel wide will be two pixels wide - hence 2.5 m resolution (approximately). It is an approximately linear relationship between the inverse of the distance and the size. However, you'll see four times the detail - conside...

prao

Due to communication time lag between earth and moon, the final descent to and landing on the moons surface has to be autonomous. I suppose this would require non trivial re-configuration of the yaan's mission profile and therefore unlikely. De-orbiting to lower altitute seems doable and more usefu...

prao

Would it be possible to attempt an kind of survivable soft landing for the CY mother ship at eom. May be spin up and use the LAM and attitude thrusters.....?? Thanks Interesting idea. Some points to consider: Currrently CY1 has 50% more fuel than it requires for the 2 yr mission so perhaps there wi...

prao

Good points all.

prao

Cutting edge An afterthought The MIP might have been an afterthought and may have been added because a person of Shri. Abdul Kalam's stature suggested it. It is also possible to claim that its inclusion compromised the mission's original objectives. But these arguments do not take into consideratio...

prao

SSSalvi wrote:
Thanks Rao for bringing out the woes of a design engineer. You said it!

prao

hmm... how the orbital height has any significant effect on CY1's temperature ? Reports from ISRO indicated that reflected radiation from the Moon was one of the factors that caused the temperature rise. Apparently an increase in orbital height to reduce these effects was one of the options conside...

prao

8. The reality is that we built a more functional, utilitarian probe for much less than the Japanese. 9. The heat issue is not a major problem in that simple measures like not using the high voltage instruments continously + changing the orientation of the craft with respect to the sun while keepin...

prao

does this video match or better kayuga? Way better than Kayuga. Screw the HDTV. Screw too their crystal clear blue Earth and gray gray grayish lunar terrain, as if someone vomited Tejas' gray color scheme on a ship deck. ...deleted Why? Why be so jingoistic? Is there any purpose served? And just to...

prao

It certainly does look like the camera has been turned sideways. I wonder if its a consequence of the 20 deg rotation performed recently. All available info indicates that the camera is normally to point straight down. The camera also has CCD's ahead and behind the central CCD that view the terrain ...

prao

Woo hoo! :D Congrats ISRO! From this link posted above by SaiK: The 35-kilo payload crash-landed on the lunar surface at around 2030 hrs IST. The MIP has started sending its first signals to the satellite. and Closer to the surface, rockets were fired to slow down its speed and soften impact . This...

prao

At least now I hope the events up to the landing (crashing?) of the MIP will be made clear. Main uestions in my mind: Was the MIP completely destroyed upon reaching the Lunar surface? Did any rocket fire anytime before touchdown to slow down the descent? Did it continue transmitting after touching t...

prao

Wonderful wonderful achievement

Congratulations ISRO! India and Indians the World Over are proud of you!

prao

Chinese scientist calls for co-op between Asian space powers http://www.chinaview.cn 2008-11-12 21:06:43 Print BEIJING, Nov. 12 (Xinhua) -- 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...

prao

The problem is that the Moon has a more complex motion than the Earth ( orbiting both Earth and Surya) FWIW - Don't know exactly what one means by "more complex motion" but both earth and moon orbit around the sun in a more or less an elliptical, orbit (with nearly same "e" and ...

prao

There is a time delay integral tutorial for pushbroom imagers here that may be relevent to the TMC functioning.. In addition, with only a single pixel to collect photons for that very short amount of time, there's two serious limits on the sensitivity: dynamic range and signal-to-noise ratio of the...

prao

Indeed, plastic models of Indian rockets was what I was looking for when I came across the paper models. You'd think (hope?) that there might be some enterprising company that would try to leverage the pride among Indians to build and sell models of Indian rockets and satellites but I could find no...

prao

Came across this very interesting website of a Mexican gentleman who builds ingenious paper models. One of his paper models is India's very own GSLV! Indications are that a PSLV paper model is in the works too. Plans are posted. Here's the website: http://www.chihuahuadepapel.com/index.htm He is go...

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