Tiangong-1 reentry window narrowed to only 3.4 hours and two orbits

The sky is falling! The Tiangong-1 reentry window has now been narrowed to only 3.4 hours and two orbits, centered on 8:30 pm (Eastern) on April 1.

It appears the world might be dodging this very minor bullet. The new window, which the spacecraft has just now entered as I write this, has allowed for the first prediction on where it should come down, and it appears that this will be in the southern hemisphere in the Pacific west of South America.

Update: Tiangong-1 came down in the Pacific Ocean at 8:15 pm (Eastern) on April 1.

Tiangong-1 re-entry window narrowed further

New calculations have narrowed the reentry window for Tiangong-1 to sixteen thirty-six hours, centered at 6:30 am (Eastern) on April 1.

This means reentry could come anytime during the 11 or so orbits from 10:30 pm (Eastern) on Saturday March 31 to 4:30 pm (Eastern) on Sunday April 1.

This post was incorrect, as the estimate was really 32 hours centered on 6:30 am (Eastern on April 1st, not 16. See my more recent post with an update.

Tiangong-1 reentry window narrowed to 24 hours centered on April 1st

Tiangong-1 landing possibilities

The reentry window for Tiangong-1 has now been narrowed to 24 hours, centered on April 1st. It is still too soon, however, to determine where it will land. The map on the right shows the likeliest regions in yellow, the next likeliest in green, and areas with no chance of impact in blue.

The focus so far has been on where the surviving pieces of Tiangong-1 might land. The summary at the link notes that it also will provide an interesting fireworks display.

It may be possible to see Tiangong-1 reentering depending on your location, the time of day, and visibility during reentry which will not be known until a few days prior to the event…. Visibly incandescent objects from this reentry will likely last tens of seconds (up to a minute or more) in contrast with the vast majority of natural meteors which last mere seconds.

…Depending on the time of day and cloud visibility, the reentry may appear as multiple bright streaks moving across the sky in the same direction. Due to the relatively large size of the object, it is expected that there will be many pieces reentering together, some of which may survive reentry and land on the Earth’s surface.

The spacecraft does carry toxic hydrazine fuel, so if by some miracle a piece falls near you don’t touch it.

Tiangong-1 re-entry narrowed to four days centered on April 1

Tiangong-1's likely landing locations

China’s first space station, Tiangong-1, is now predicted to crash to Earth in a window that has been narrowed to four days centered on April 1. The map to the right shows the station’s most likely landing areas, with yellow the most likely, green less likely, and blue not at all. Essentially, there is about a 50-50 chance the station will come down in the north mid-latitudes, with about a 70 percent chance it will land in water if it does so.

Thus, the odds of the station hitting a populated area is not large, but it definitely exists. We will not know the exact area of impact until very close to the moment the station finally comes down.

Tiangong-1 reentry window narrowed

Tiangong-1 re-entry map

New estimates by the European Space Agency of when China’s Tiangong-1 space station prototype will re-enter the atmosphere have now been narrowed to one week, centered on around April 4.

The map on the right, created by the Aerospace Corporation, indicates the latitudes where the module is most likely to fall. Yellow is the more likely, green is less likely, and blue is no chance at all. Note that Aerospace has not yet narrowed its re-entry window, still holding it at two weeks centered on April 4.

Tiangong-1 reentry update: April 3rd, give or take a week

Tiangong-1 landing map

Link here. Right now the de-orbit window of the dead Chinese space station suggests it will come down to Earth sometime around April 3, plus or minus a week. As we get closer this will get refined somewhat, but the uncertainties are always going to be great, until the actual moment it hits the atmosphere.

The map on the right, reduced to post here, comes from the link and was produced by the Aerospace Corporation and indicates the relative possibilities of debris falling in a given region.

Yellow indicates locations that have a higher probability while green indicates areas of lower probability. Blue areas have zero probability of debris reentry since Tiangong-1 does not fly over these areas (north of 42.7° N latitude or south of 42.7° S latitude). These zero probability areas constitute about a third of the total Earth’s surface area.

Depending on orbit, and whether the station is heading north or south in its orbital inclination, the odds of it crashing in populated areas changes significantly. If it is moving north the odds of coming down in the populated mid-latitudes of the northern hemisphere go up considerably. Of course, it could just as well come down in the northern mid-latitudes above the Pacific.

Regardless, the risks remain tiny, no matter what. Tiangong-1 is a small module, just large enough for some of it to survive reentry.

Tiangong-1 reentry now estimated between March 25 and April 17

China’s first space station, a test module called Tiangong-1, is now expected to reenter the atmosphere and crash to Earth sometime between March 25 and April 17.

The Tiangong-1 space lab was launched in 2011 to test docking technology and life support by hosting two crews, but loss of control over the spacecraft’s propulsion means it cannot be deorbited in a controlled manner.

The spacecraft’s orbit is decaying due to atmospheric drag and that process is accelerating as Tiangong-1 runs into denser concentrations of particles at lower altitudes.

The station will break-up during reentry, and most of it will burn up. However, some chunks will hit the ground. The article gives details about how they are tracking it in preparation for reentry.

ESA to lead international effort to track falling Chinese space station

The European Space Agency has taken the lead position in an international effort to track China’s falling Tiangong-1 test space station module.

The goal of the effort is to improve the accuracy of predicting the fall of such objects. Tiangong-1, at 8.5 tons, is big enough for some pieces to survive re-entry and crash to the ground. Improving the predictions of where it will fall will reduce the chances of the debris causing harm.

I first read of this effort from this news story, which contained in its last sentence one piece of interesting news having nothing to do with Tiangong-1:

The next such launch [of a Chinese space station module] will be of the Tianhe core module around 2019 on a new Long March 5B rocket, the country’s largest and most powerful so far. [emphasis mine]

It appears China has quietly renamed its big Long March 5 rocket, adding a “B” to the name. This name change strongly indicates what I have suspected for months, that the July launch failure has required China to significantly redesign the rocket. Apparently, the poor performance of the rocket’s first stage engines was caused by fundamental design problems.

China’s first test space station, Tiangong-1, is out-of-control

The orbit of China’s first test space station, Tiangong-1, is quickly decaying and the station is shut down with no way to bring it down in a controlled manner.

The Chinese space station is accelerating its fall towards us and will reach the ground in the coming months, Harvard astrophysicist Jonathan McDowell told the Guardian. It is decaying quickly and he expects “expect it will come down a few months from now – late 2017 or early 2018”, he told the paper.

The Tiangong 1 station was launched in 2011 as one of the great hopes of the Chinese ambitions in space, and as part of a plan to show itself off as a global superpower. The country’s space agency referred to the station as the “Heavenly Palace” and conducted a range of missions, some of which included astronauts.

But last year scientists at Chinese’s CNSA space agency said that they had lost control of the lab, and that it would now be heading towards Earth. That put an end to months of speculation, as experts watching the path of the station suggested that it had been behaving strangely.

As with many other similar objects coming down from orbit, the odds of any pieces hitting anyone is quite small. Still, China is a signatory to the Outer Space Treaty, and that makes them liable for any damage done by their spacecraft when they return to Earth.

China shuts down its first space station

Though still in orbit, China has turned off Tiangong-1, its first space station, launched in 2011 and since visited by three manned crews.

The news story, from the state-run Chinese news organization, notes that the module’s orbit will slowly decay and eventually burn up in the atmosphere. It does not say how the Chinese intend to control that re-entry, since Tiangong-1 is likely large enough for some parts of it to survive and hit the ground.

An update on the Chinese manned program.

An update on the Chinese manned program.

The original script called for [the space station] Tiangong 1 to be followed by Tiangong 2, which would have been a module of the same basic design as Tiangong 1. Tiangong 2 was expected to have tested more advanced life-support systems than Tiangong 1, but there would be no major changes to the spacecraft. It was expected that two or three crews would be launched to this module.

Towards the end of the decade, China would then launch Tiangong 3, which was slated to be an entirely different class of spacecraft. It would be larger and more capable. Tiangong 3 was expected by some analysts to be a precursor to the types of modules to be used in China’s future space station, slated for launch around 2020.

According to Yang’s presentation, we can forget about Tiangong 2. Or at least, we can forget about Tiangong 2 as it was originally planned. China still plans to launch a mission with this name, but it would seem that the large laboratory module originally known as “Tiangong 3” has now been designated as the new Tiangong 2.

In other words, China is accelerating the admittedly slow pace of their manned program.

China is in its final preparations for the launch of its next manned mission.

The new colonial movement: China is in its final preparations for the launch of its next manned mission, expected any day now.

This is the key quote from the article:

China aims to build a space station around 2020 based on the space rendezvous and docking technology that is currently being tested. Several components will be sent into space separately before being assembled into a space station through a variety of docking procedures.

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