India successfully shoots down satellite in space • Hacker News Board

Re: India successfully shoots down satellite in space

#81

Post by dugluak » Wed, Mar 27, 2019, 6:50 PM UTC

garmaine wrote: post #79

z3phyr wrote: post #46

Earlier quoted context omitted.

Then everybody will do it secretly. It's only a travesty when someone starts it; other people have the right to respond to parity with their own.

There's no way to secretly test these weapons. To be clear, I'm not objecting to the weapons existence. I'm objecting to the tests, which are potentially worse than above-ground nuclear testing. The kessler syndrome, if realized, would permanently destroy our ability to deploy, access, and use space resources.

How many tests did US conduct since 1950s?

Re: India successfully shoots down satellite in space

#82

Post by burfog » Wed, Mar 27, 2019, 6:51 PM UTC

Pharmakon wrote: post #62

jdsully wrote: post #47

Earlier quoted context omitted.

A missile can be viewed from many angles. A beam of light is (mostly) only visible by whoever its aimed at. Light dispersion not withstanding. Sunlight is quite bright and will mask a lot of the scattered light as well.

The effects of a beam of light strong enough to push a satellite into a rapidly decaying orbit would bloom like mad through the atmosphere, and create very detectable thermal effects. It would be detectable in a number of wavelengths for a staggering distance. You’d also have to impact the satellite so strongly that its station-keeping thrusters would be insufficient, while account for losses through the atmosphere.…

Some of it makes plenty of sense.

The atmosphere is hardly a problem. You'd use numerous beams simultaneously, fired from all over the country. No single beam would be powerful enough to cause atmospheric breakdown. The sensible choice is to surround every power plant with lasers.

No, this won't be undetectable.

Light pressure is fine, but probably not as productive as ionizing the surface to produce thrust. With high power, atoms at the surface can become multiply ionized. They get blasted off the surface. This would be pulsed, since otherwise the resulting ions would absorb some of the beam and there would be a risk of melting the surface.

If the thrust isn't enough, for example due to a very high orbit, you can just keep going until the target is gone.

Weather isn't much of a problem. There is probably clear weather somewhere over the country. Station keeping won't last forever.

Oh, and if you don't insist on a neat and tidy removal, you can just use non-pulsed beams to melt the target.

Re: India successfully shoots down satellite in space

#83

Post by Pharmakon » Wed, Mar 27, 2019, 7:03 PM UTC

burfog wrote: post #82

Pharmakon wrote: post #62

Earlier quoted context omitted.

The effects of a beam of light strong enough to push a satellite into a rapidly decaying orbit would bloom like mad through the atmosphere, and create very detectable thermal effects. It would be detectable in a number of wavelengths for a staggering distance. You’d also have to impact the satellite so strongly that its station-keeping thrusters would be insufficient, while account for losses through the atmosphere.…

Some of it makes plenty of sense. The atmosphere is hardly a problem. You'd use numerous beams simultaneously, fired from all over the country. No single beam would be powerful enough to cause atmospheric breakdown. The sensible choice is to surround every power plant with lasers. No, this won't be undetectable. Light pressure is fine, but probably not as productive as ionizing the surface to produce thrust. With hig…

Right, the issue though isn’t if it’s technically possible, but that it would somehow be advantageous compared to a missile. I grant that it can be done, I’m still unsure as to why. Nonetheless I appreciate your analysis!

Re: India successfully shoots down satellite in space

#84

Post by KorematsuFred » Wed, Mar 27, 2019, 7:03 PM UTC

To give a context to why this is important (even though technologically it is much easier to shoot a satellite).

Western Nations often have this tendency of pass international laws with exceptions for themselves using ridiculous arguments. Such as nuclear proliferation treaties which allows existing nuclear powers to build more nuclear war heads but does not allow others to build even the first nuke.

India's NSA Ajit Doval in 2011 had pointed out that this is going to happen to satellite sabotage as well. The existing players will gang up to ban such weapons while making exemptions for themselves. By publicly showing and acknowledging this capability India has ensured a seat at the table in future.

Re: India successfully shoots down satellite in space

#85

Post by i2shar » Wed, Mar 27, 2019, 7:19 PM UTC

nashadelic wrote: post #70

Strangely, I'm not seeing a wide enough condemnation of this. Another country is building destructive weapons, bringing down LEOs; how is this a good thing? All the while the region suffers from chronic poverty, poor access to clean water and basic services. Sending a science mission to space is great and rightly lauded, this is wasteful and energies spent better elsewhere.

So you mean US shouldn't spend a dime on technology before the last homeless person in SF is rehabilitated?

Re: India successfully shoots down satellite in space

#86

Post by [deleted] » Wed, Mar 27, 2019, 7:22 PM UTC

vtbprog wrote: post #77

stunt wrote: post #57

Such a huge step toward more peace in the world. What do you expect when world major democracy advocates are also the world major weapon sellers. I don't think there is any technological glory on destroying a satellite that deserves such a public announcement. Perhaps it is far less complicated than putting a satellite into space which is what India was already good at it.

>>I don't think there is any technological glory on destroying a satellite We are talking about the capability to track and destroy a live satellite in space in under a span of 3 minutes with precision. There is a significant amount of technology involved here right from the types of propellants, precise navigation controls to steer rock in a specific direction...all of which has been developed indigenously. This tec…

[deleted]

Re: India successfully shoots down satellite in space

#87

Post by nindalf » Wed, Mar 27, 2019, 7:26 PM UTC

eklavya wrote: post #55

nindalf wrote: post #17

Earlier quoted context omitted.

Modi takes the credit for anything achieved by the government or government backed entities like the space organisation. He singlehandedly opened bank accounts (that are empty), surgically struck Pakistan (with his bare hands), got us to space, developed missiles, brought the black money back, won the cricket world cup, created jobs, built the mandir (that's built, right?) and a million other achievements. What's cur…

Sure, why not? Take credit for whatever you have done, it's naive to think that politicians will not showcase their work. Tell me what do you write in your resume? Finding personal faults with any public person is pointless (as in having an effect on you). What matters is whether the results are good/bad.

I have 2 issues with what Modi does

* His list of achievements is absurd and factually incorrect, and he rarely gives credit to others who contributed.

* He hates criticism and tries to muzzle it. A politician should not interfere with the press but he does so. He has gotten journalists fired because they criticised him.

Re: India successfully shoots down satellite in space

#88

Post by [deleted] » Wed, Mar 27, 2019, 7:29 PM UTC

MiroF wrote: post #50

thevardanian wrote: post #38

Earlier quoted context omitted.

So... Don't announce scientific achievements by your national space agency during an election? Talk about skewed perspectives.

Wait, now I'm confused... is it a military national security issue or a scientific achievement? China managed to not have Xi Jinping announce when they did it.

[deleted]

Re: India successfully shoots down satellite in space

#89

Post by lodi » Wed, Mar 27, 2019, 7:44 PM UTC

natch wrote: post #65

yumraj wrote: post #61

Earlier quoted context omitted.

According to the FAQ put out by Gov of India [0] V. Does the test create space debris? The test was done in the lower atmosphere to ensure that there is no space debris. Whatever debris that is generated will decay and fall back onto the earth within weeks. [0] https://www.ndtv.com/india-news/soon-after-pm-address-foreig...

Unless some pieces were boosted higher by the explosion. But I guess they are confident this could never happen.

When you boost an orbiting object in this manner there's only two possibilities for what can happen next:

a) you give it enough energy to reach escape velocity, in which case there's no problem.

b) you blow out the circular orbit into a long ellipse. The far end, apogee, can be very far out depending on how much energy you added, but the near end, perigee, is always at the same altitude as it was at the moment of impact. Therefore, as long as the satellite is "within" thin atmosphere at the moment of impact, the fragments will periodically pass through thin atmosphere as well.

To properly boost yourself into a higher (circular) orbit you need to give yourself two kicks: one to raise your apogee, and then half an orbit later another to raise your perigee to match.

Re: India successfully shoots down satellite in space

#90

Post by natch » Wed, Mar 27, 2019, 8:03 PM UTC

6gvONxR4sf7o wrote: post #69

natch wrote: post #65

Earlier quoted context omitted.

Unless some pieces were boosted higher by the explosion. But I guess they are confident this could never happen.

Orbits are periodic. If it is boosted up, it'll come back down. Orbital decay will still happen.

Yeah it will come down... nobody is disputing that. The worry is that in the meantime it could hit some other satellite, causing more debris. Yes the likelihood is vanishingly small. But the consequences of an unlucky event could be large.