India Ruined Space? - Page 1
Forum section: electronics / general

author: metrologist
author_rank: Super Contributor
timestamp: April 03, 2019, 01:47:56 am
content: I came across this article and it seems quite worrisome. But then I realize a country like the US has an order of magnitude+ more garbage out there. Is this really significant?https://amp.businessinsider.com/nasa-space-junk-india-destroying-missile-threaten-international-space-station-terrible-thing-2019-4I recall something about the US blowing out millions of copper needles into orbit for some experiment, and that is still a problem. Space could be the new terrorist frontier...

author: golden_labels
author_rank: Super Contributor
timestamp: April 03, 2019, 02:52:59 am
content: The event itself seems to be true:AlJazeera,Routers.According to ESAthere is over 934k human-produced objects bigger than 10mm around Earth and over 128M pieces larger than 1mm.According to the Business Insider’s article, the test produced 6.5k of objects >5mm. That is between 0.7% and 0.05% increase.According toBBC,space.comandthe video of Jim Bridenstine explaining the issue, the estimates are at 400 pieces of debris (0.04%–0.0003%) with 60 pieces (0.006%–0.00005%) being big enough to be tracked and 24 being above ISS orbit.According tospace.com, India’s Ministry of External Affairs claims that the satellite has been chosen to produce debris that will decay quickly.This is the 7th object destroyed in space as a part of military tests, with the first to do so being PRC (Wikipedia article on the test), followed by United States (Wikipedia description of Operation Burnt Frost).____¹ I have issues recognizing faces, so I am not 100% sure this is Bridenstine — but he looks like him.

author: extide
author_rank: Regular Contributor
timestamp: April 03, 2019, 04:05:17 am
content: Actually, the first was the soviets in 1970, I believe, and then the US in 1985. Those were the first successes, at least, with tests going back to the late 50's or early 60's.The Chinese one was a bit of an issue because it was so high up meaning the debris will stay up there for a long time.The Indian sat was in a much lower orbit, which means there is quite a bit of debris risk to ISS as it's also in a pretty low orbit, but the most of the debris should re-enter pretty soon. (within weeks, vs the Chinese one that happened over a decade ago and much of it still remains and will do so for quite some time)

author: metrologist
author_rank: Super Contributor
timestamp: April 03, 2019, 04:08:26 am
content: He  said, we are charged with commercializing low space orbit. That is NASA's new charge?He said the risk to ISS was increased 44%, in ten days.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 03, 2019, 04:38:12 am
content: Something is funny here. First to think that they have an estimate of the increase in risk of 44% (not 43%, not 45%) based on debris they can't track and can only estimate size and quantity indicates someone is playing fast and loose with numbers. Also, if the risk without the Indian experiment is within 44% of a totally unacceptable value someone is playing a fools game. The shuttle program indicated that we cannot predict risk correctly within a couple of orders of magnitude. The risk is virtually always substantially higher than calculated because risk calculations only account for what you understand and know about. Its those unknown unknowns that really get you. The histrionics about the danger to the ISS are some sort of political gambit, nothing based on real science in my opinion.That said, space junk is a real problem, and the Indian approach of doing the test at low altitude where the junks lifetime is shorter at least shows they may have been trying to do the right thing (we won't mention that low altitude intercepts are easier energetically, easier to do telemetry and so on). If India really intends to be a space power as they state, it will be in their own self interest to limit the amount of junk flying around.

author: extide
author_rank: Regular Contributor
timestamp: April 03, 2019, 05:00:04 am
content: Well, remember they said the risk increasedby44%. That increase was based on what was tracked an modeled.Say their risk was 1% beforehand, it would now be 1.44% (of course the real numbers are significantly lower than this, I believe, but you get the idea). Also that risk number is only talking about an MMOD strike, so it isn't including unknown unknowns, or even the other known unknowns.

author: golden_labels
author_rank: Super Contributor
timestamp: April 03, 2019, 07:05:08 am
content: extide:I wasn’t aware that either of them succeeded in destroying an actual object on an orbit. Thanks. But still the general image is right: India is far from being the first one to conduct such an experiment and the criticism comes from an agency of a state that did it earlier.CatalinaWOW:I believe that value is calculated using the same method as they use for the typical risk estimation. Whatever that method is and how big error it introduces becomes unimportant, because in both estimates the relative error may be similar: by both magnitude and direction. (a + ε) / (x·(a + ε)) is 1/x for any positiveaandε.What is missing from the message is the duration of that risk increase. The debris may pass the orbit of ISS only once and then never visit it again; it may cross it but never be at the same place as ISS; it may share the position with ISS for 10 minutes or 10 days. 44% increase during 10 minutes is not the same as 44% increase during 10 days.

author: TerraHertz
author_rank: Super Contributor
timestamp: April 03, 2019, 08:09:54 am
content: The important point is not some calculation of risk from _this_ increment in the amount of orbital debris.Rather it's when the orbital debris reaches some critical density, that starts a chain reaction of collisions with intact satellites. A 'collision cascade', with each impact producing a lot more random orbital crap. Ending up with so much that any new space mission passing through the junk zone, has a probability of getting hit that is too high to risk.No one is able to calculate when that might happen. Just that when it does, space will be closed to humans for generations.If I was planning a series of missions to set up a colony on Mars, I'd bear in mind the detail that an orbital collision cascade might happen around Earth anytime, making further supply missions (and return of the Mars crews) impossible. This is the kind of scenario Murphy lives for.Another possibly relevant detail. Who remembers that Nth Korea launched two quite large objects into orbit some time ago? These appeared to be inert, in that they never sent any messages or did any maneuvering. So everyone wonders what they are.My thought: insurance policies. A ton or so of gravel, with an explosive charge. To fire upon command, or perhaps loss of dead-man signals. Nth Korea saying "if you nuke us, you lose all your military and civilian satellites and access to space, for a long time."

author: EEVblog
author_rank: Unknown
timestamp: April 03, 2019, 08:25:08 am
content: Quote from: extide on April 03, 2019, 05:00:04 amYes. If the risk was really 44% of an impact in a given time (say a month) then the ISS would already have holes in and they would be bring the crew home.

author: EEVblog
author_rank: Unknown
timestamp: April 03, 2019, 08:27:36 am
content: Quote from: TerraHertz on April 03, 2019, 08:09:54 amTime to send up Clint Eastwood and Tommy Lee Jones!

author: soldar
author_rank: Super Contributor
timestamp: April 03, 2019, 09:50:06 am
content: Quote from: golden_labels on April 03, 2019, 02:52:59 amThanks for a well researched and documented post.

author: bd139
author_rank: Super Contributor
timestamp: April 03, 2019, 10:16:14 am
content: Quote from: EEVblog on April 03, 2019, 08:27:36 amJust keep Bruce away

author: bsudbrink
author_rank: Frequent Contributor
timestamp: April 03, 2019, 03:05:22 pm
content: Quote from: EEVblog on April 03, 2019, 08:27:36 amNa, send Quark:https://en.wikipedia.org/wiki/Quark_(TV_series)

author: Red Squirrel
author_rank: Super Contributor
timestamp: April 03, 2019, 03:21:17 pm
content: We need TARS... JANITARS.

author: Gyro
author_rank: Super Contributor
timestamp: April 03, 2019, 09:05:39 pm
content: To quote the late, great, Douglas Adams...QuoteLuckily the human race only capable of ruining the neighbourhood.