Another good excuse for a sunset or sunrise date: Last Chance to See Doomed Chinese Space Station - Sky & Telescope Launched in September 2011, Tiangong-1 (Chinese for "heavenly palace") was China's first space station. After several successful manned and unmanned missions, Chinese National Space Administration (CNSA) officials extended the spacecraft's life for two years until they lost telemetry in March 2016. By June of that year, amateur satellite watchers reported that the station was out of control, a fact that the CNSA finally conceded three months later. The original plan was to de-orbit the space station with a controlled thruster burn for a safe breakup over the Pacific Ocean. But without telemetry, the craft can no longer be controlled, so re-entry depends entirely on the vagaries of atmospheric drag complicated by the effects of Sun-driven space weather. . . . To find out when and where to look from your location, go to Heavens Above and login. If you're not registered, you can still click the Change Your Observing Location link in the column on the left side of the opening page to add your city. Then return to the opening page and click the Tiangong-1 link to get a table of upcoming passes. If you click the date link, a map showing its path pops up. Because of its evolving orbit, pass times may vary a bit. The space station will look just like a star moving from west to east across the sky. . . . Bob Wilson
One of my wife's friends lived on a very big farm in Western Australia. A piece of Skylab landed on her farm when it fell back to Earth. She said it was all very exciting.
Gravity was very little besides visual special effects. Difficult to care much about the (1 and a half) characters in the movie. Tiangong zinging in was a good special effect, all the same.
Yes, I'd heard this. And the only opportunity I've had to watch it was on a 10" screen on a plane, and I thought that wasn't really the place to watch a film that was all about the effects.
An airplane is the perfect place to see a good scary movie...especially one with plane crashes in it. But Gravity has no gravitas on such a small screen. As for that space station, to quote an infamous song: "....this could be heaven or this could be hell..." Looks like the heavenly palace is going to meet a fiery end.
Tiangong-1, soon to descend, is a single module. In Gravity movie, it was a double connected at right angles. Which is not the case for Tiangong-2 either, but movies, OK?. AFAIK, TG-2 is not going to have any more visitors. Presumably, when its deorbit time comes, controllers will still be controlling and they'll dump it in Pacific as is the normally done thing. Next year maybe China will begin construction of their 'keeper' called large modular space station. Needs a better name. That is planned to have 3 separately launched modules linked. After anticipated 10 years it'll get a similar dump. So not only is ISS the biggest and most expensive, it is of longest duration and still going. Have heard rumors that it has become a bit odoriferous over time.
If this event gets folks out looking for orbiting sats. after sunset I'd call that a good thing. They are pretty nifty especially ISS it is big and bright.
Also try to get out to spot the (almost useless space junk) Humanity Star before it dramatically de-orbits in several months time. Their web site has the tracking info, hit the Find My Location button and look to the far right which has scrollable viewing info on the next closest pass. Just before dawn or right after sunset are the only real viewing times. It has been too cloudy here to see it yet.
Link@13 is not getting updated and shows minimum altitude (apogee) about 255 km on Feb. 8 Now it's Mar. 12 (0n this side of the 'line') and apogee on previous orbit was 235 km according to Stuff in Space stuffin.space gets their orbital elements daily from Space-Track.org. Later seems to have best available public data but one must log in etc. stuffin.space has impressive computing behind impressive graphics. Made by a college freshman??? Dang. == Anyway TG1 orbital decay will continue to steepen, towrds final day which is ??? Read somewhere that solar panels would come off at 95 km. That's also altitude where asteroids get all glowy.
If stuff in space is accurate, TG1 lost a km of apogee in the most recent orbit. To me this suggests 130 orbits or less remain. 90 minutes each would suggest 8 days. Not more. Is this consistent with anything new you've read?
Heavens-Above is showing orbital height of 230-252 km, and 16.12038581 revs per day (89.33 minutes/rev), as of 11 March 2018 17:40:45 UTC.
Apogees vary vary among geographical models. I missed a couple of orbits, but interested in SIS next time around low. Apogee is when an orbiter carries the most kinetic energy but also encounters most drag. So neat that we can now observe (even approximations of) down going.
Updated to 229-251 km, 16.12386309 rev/day (89.31 minutes/rev) as of 12 March 2018 10:31:20. That is a drop of 1 km in just under 17 hours. But because of rounding to the nearest km, that doesn't tell us much yet. The higher resolution of the revs/day figure should reveal far more, but the handy-dandy equations that I used to use are buried very deep in my library back home (not where I am now), and haven't seen daylight this century. Perhaps someone else is more fresh on this. ========================= A quick online lookup of Kelpler's Laws plus a bit of calculation from the period, suggests this was a drop of 0.951 km. Scaled to 24 hours, that is dropping 1.35km/day. But someone else with less sleep deprivation should recheck this. I could easily have botched some calculation.
