China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
(OP)
China's Tiangong-1 space station will crash to Earth within weeks
Experts say it is impossible to plot where module will re-enter the atmosphere, but the chance is higher in parts of Europe, US, Australia and New Zealand
https://www.theguardian.com/science/2018/mar/06/ch...
Experts say it is impossible to plot where module will re-enter the atmosphere, but the chance is higher in parts of Europe, US, Australia and New Zealand
https://www.theguardian.com/science/2018/mar/06/ch...
John R. Baker, P.E. (ret)
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
"The US-funded Aerospace Corporation estimates Tiangong-1 will re-enter the atmosphere during the first week of April, give or take a week. The European Space Agency says the module will come down between 24 March and 19 April."
Yes, technically, there is a slight difference between 'the first week of April, give or take a week', and 'between 24 March and 19 April', but in this context, the difference is not particularly meaningful.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Andrew H.
www.mototribology.com
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Another is how many small space garbage is it collecting, vs how much is it depositing?
Is there a positive here, or is it all negative?
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
The stuff it is collecting is essentially irrelevant, as they are extremely small. Whatever it winds up generating will virtually all fall back to Earth, since they'll be in too low an orbit to be sustainable. Anything big that it hits will likely result in a spray of particles and objects, and would be a losing proposition.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Wiki says: "Orbital inclination: 42.8 degrees"
Anyone north of about 43°N or south of about 43°S is probably safe. At least from this particular risk.
Checks location, confirms 45°N. Phew!
Fairly good odds (50-50) it'll hit the Pacific... ...maybe.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Re-entry, start to finish, can cover a couple thousand miles. But once it starts, any drag or tumbling in the atmosphere would be closely followed by almost immediate disintegration into bits, so that tumbling would merely adjust the outcome within a small region. Drag while still in the very wispy upper reaches would be affected by the station's aspect angles relative to the movement; so you'd have a good point there.
Tidbit: The Apollo CM had manoeuvring capabilities during re-entry, so they could be steered to land a few miles from the recovery fleet, if they were skilled and lucky on the day. The CM actually went back up (400,000 feet ?) to cool off, and then fall back down again.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
I also assume the orbit is a little out of round, so it would have some high and low points in the orbit.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Ref: http://www.heavens-above.com/orbit.aspx?satid=3782...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
For comsats in geostationary orbits, there is a protocol that requires spacecraft to reserve enough fuel for them to be put into parking orbits away from useful slots, to prevent collisions when replacements are sent up. And at least Iridium, if not others, using low orbits, has (had?) planned for de-orbiting fuel reserves, i.e. dropping their spacecraft back into the oceans, to similarly keep their orbit stations clear and also to drop them into less populated areas.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
The Apollo CM had to be steered into a fairly narrow re-entry corridor, to avoid burning up or skipping back out. So the CSM (CM + SM still attached) was steered into the approach corridor (using thrusters) before the SM section was jettisoned. Once the CM was on its own [and in the atmosphere], they could use aerodynamic steering by rotating the CM on its yaw (?) axis, using little thrusters to turn, to have the center of mass above or below the center of pressure. It actually went back up, trading speed for huge altitude gain (for cooling). One benefit of this steering was that it widened the allowable corridor from something like 2°, which was impractically narrow and thus dangerous, to a more reasonable 8° (these numbers from memory, so might be incorrect).
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
part 2: https://www.youtube.com/watch?v=cOiVKUI07G0
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
The YouTube channel that hosts those videos does have a bunch of other old training films (from WW2 onwards), and yes, the level of information and use of humor make for good watching.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Apogee Books: http://www.cgpublishing.com/
STF
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Skylab
STF
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
- Russian satellite Kosmos 954 made a big radioactive mess in Canada's Arctic.
- Apollo 13's LM contained an RTG. Famously the LM was unexpectedly used to get home. But not so unexpectedly that NASA didn't plan for exactly this sort of thing. They put the plutonium core in a cask for safety.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
So the takeaway I am getting is, if it lands in your backyard, don't touch it. One should remember that from the old sci-fi movies.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
"Apollo 13 carried the SNAP-27 radioisotope thermoelectric generator (RTG) that was supposed to be left on the moon to power experiments. It had been engineered to make it back to Earth intact, just in the event of exactly such an incident (the LM as Lifeboat scenario). [Somebody should get a Nobel Peace Prize that that decision!] The plutonium apparently survived reentry and came to rest with what remained of the lunar module in the Tonga Trench south of Fiji, approximately 6-9 kilometers underwater (exact location is unknown). Extensive monitoring of the atmosphere in the area indicated that no radiation had escaped."
Edit:
See diagrams and pictures here: https://en.wikipedia.org/wiki/Apollo_Lunar_Surface...
"The RTG cask stored the plutonium-238 fuel element. It was located to left of the SEQ bay. The cask was designed to withstand a launch vehicle explosion in the event of an abort or a re-entry into Earth's atmosphere (which is [EXACTLY] what occurred on Apollo 13). The picture shows Edgar Mitchell practicing the removal of the fuel element."
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
http://www.dailymail.co.uk/news/article-5486985/Lo...
BTW, my wife and I are flying to Detroit on April 10th, which is at the edge of the current impact 'window', and we'll be staying, at least for the first few days, well within the 43 degrees North Latitude limit.
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
1) "cone of silence" (get smart), and
2) "surround the camp with a ring of steel" (hogan's heroes)
another day in paradise, or is paradise one day closer ?
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
I cant wait to see what the locals do this time. :D
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
A space station from China is expected to crash into Earth next week
http://wjla.com/news/offbeat/a-space-station-from-...
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
From logic, I can't figure out the forces that would make an orbiting body launched due east to move back across the equator.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
What causes orbital perturbations? A couple of things - gravity tides from the moon and sun will tend to pull on a spacecraft in a purely equatorial orbit, shifting its orbital plane over time. Also the gravity field of earth is not uniform, there are some significant mass concentrations (google image search for earth gravity map) that perturb spacecraft orbits.
https://en.wikipedia.org/wiki/Orbital_station-keep...
But Tiangong was not in a purely equatorial orbit, it was launched at a latitude some distance above the equator, so it orbits at an angle to the equator. Not all spacecraft are launched due east, necessarily, they are launched and gain velocity in whatever direction you want the final orbit to be in, or whatever vector the rocket engines pushed in, hopefully those were the same. If launched from say, 45 deg. N, earth's rotation only gives you some 70% of the eastward velocity vector that you get at the equator, which is significant, but it's still only a fairly small fraction of the velocity needed for a stable orbit. And remember, the orbit has to be centered on earth's mass, so if you launch :due east" from 45N, you will still end up in an orbit with at least 45 deg. of inclination, your extra east velocity ends up pushing your orbit inclination more northerly. You might need to grab a ball and some rubber bands to help you visualize it, or a good map with "great circle" shipping/flying routes shown on it. In general, the minimum fuel to low orbit puts you in an orbit with an inclination close to the launch latitude.
FWIW, it's not "intuitive", it takes a bit of study and/or practice. Watching my kids figure out Kerbal Space Program was a lot of fun - and I was surprised how quickly they started to figure this stuff out. Now #2 son is off doing some programming to put KSP-type interfaces to work for real spacecraft.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
It's moving in an orbital plane, it's just that the orbital plane is inclined to the Earth's equator. As you hinted, that's due to the latitude of the launch site (unless actively compensated).
And it's not sync to the Earth, so the equator crossings move around the Earth in longitude.
Basically, put away the map and refer to a globe. It's actually fairly simple referenced to a globe.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
...among others....stand by adventure fans!
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Do you realize that if you made a bulletproof catcher's mitt, somebody would feel obligated to try it out?
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Out-of-control Chinese space station 'will crash into Earth over weekend'
The European Space Agency has revised its prediction for when free-falling Tiangong-1 will crash into Earth.
https://www.mirror.co.uk/science/chinas-free-falli...
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Dan - Owner
http://www.Hi-TecDesigns.com
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
I'll take $50 on "if".
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
If I need to be more specific, then: the Pacific.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Also - https://xkcd.com/1337/
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
The odds of it hitting the earth are less than 25%.
The odds of it hitting the Earth are essentially 100%.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
http://www.freerepublic.com/focus/f-chat/3642715/p...
Link
Tracker link is expecting a 2 April impact.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Steve
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
http://www.satview.org/?sat_id=37820U
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
https://www.space.com/40089-china-space-station-ti...
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Link
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
Besides, if part of this thing landed in my yard, I believe it would be like winning the lottery. Who wants to buy a used Chinese space station?
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
BBC News
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...
11:33 PM, Sunday night. Claims the space station is now down about 7 minutes ago: About midway between the Brazil and West African coast.
RE: China's Tiangong-1 space station: Perhaps not a disaster yet, but keep looking-up just in case...