Category Archives: Space

SpaceX has launched a space telescope!

In their first launch of a scientific satellite for NASA, SpaceX has placed the Transiting Exoplanet Satellite Surveyor (TESS) into Earth orbit and successfully recovered the first stage.  TESS is a follow-on to the massively successful Kepler space observatory.  Like Kepler, it will use the transit observation method to detect exoplanets, but unlike Kepler, it will be an all-sky survey, reliant upon an unusual orbit in a 2:1 resonance with the Moon (to avoid ever coming too close to the Moon and having the orbit disrupted).  The orbit is completely outside the Van Allen Belts, with a period of 13.7 days.  TESS will be able to downlink to ground stations during its perigees, at a distance of 108,000 km (about three times further away than the geosynchronous ring).  Although TESS has a nominal primary mission duration of two years, this orbit is expected to remain stable for decades, and the spacecraft will almost certainly be used to destruction like so many other NASA spacecraft, finding mission extension after extension until there is nothing more that it can do.

Falcon 9’s upper stage performed two burns, and then released TESS in a supersynchronous transfer orbit; the satellite itself will finish refining the orbit.  The upper stage has by now disposed of itself over the Pacific Ocean, and the payload fairing conducted a water landing as part of SpaceX’s effort to reuse the fairings.  (The company only has one fairing-catcher ship, Mr Steve, which is currently in California, unavailable for this mission.  So far, the closest a returning fairing has gotten to Mr Steve is a few hundred yards, so there is still some refinement needed.)

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Virgin Galactic returns to powered flight!

It was three years ago that Virgin Galactic lost a vehicle and pilot in a tragic mishap caused by human error and poor human factors engineering.  But the defects have been changed so that the same mistake cannot be made again, and after an incremental test campaign with the newer version of SpaceShipTwo, VSS Unity, they were able to light the engine for the first time:

It was only a thirty second burn, but it went off flawlessly, and it puts them a step closer to operational flights!

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The Dragon Flies Again: CRS-14 Launches to the ISS

A reused Dragon capsule launched by a reused Falcon 9 first stage is now en route to the ISS.  The first stage was not recovered; it’s one of the older model stages, and SpaceX sacrificed it in order to conduct engineering tests during a water landing.  There was no attempted fairing recovery, as the Dragon capsule does not require a fairing.  But the launch was 100% successful:

Dragon is expected to rendezvous with the station on Wednesday, where it will go free-floating and be captured by the station’s SSRMS, which will pull it in to berth.

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Tiangong-1 is no more

It came down at 00:16 UTC April 12, 2018, in the Pacific Ocean, as confirmed by USSTRATCOM:

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Tiangong-1 is incoming this weekend

Well, incoming somewhere, anyway.  I can be assured of it not hitting my house, as I’m just a bit too far north, but it’s still impossible to predict where under its orbital path it will actually fall.  With luck, it will fall somewhere where it can be observed but not actually threaten anything or anyone on the ground.  😉  I’m hopeful it will fall within the gaze of the newest GOES spacecraft, which take multi-spectral images of the hemisphere containing North America approximately every fifteen seconds.  It would be a remarkably helpful bit of science.

Where will it come down?  Well, that mostly depends on *when* it will come down.  And that in turn depends on the atmosphere.  The lack of solar activity has kept our atmosphere relatively settled, which has allowed Tiangong-1 to survive in orbit a bit longer than originally predicted.  (For comparison, Skylab crashed considerably earlier than predicted, because solar maximum greatly puffed out the atmosphere, an effect which was not adequately understood at the time.)  Predicting deorbit for something with a very circular orbit is tricky; it could fall almost anywhere under its orbital path, with the extremes of the orbit being slightly more likely simply because it spends more time at those latitudes.  Here are the current predictions from the major authorities on the subject:

SatFlare: 1 Apr 2018, 06:56 (±36 hours)

Aerospace.org: 1 Apr 2018 (±2 days)

Satview.org: 2 Apr 2018, 03:09 (±8 hours)

ESA: the morning of 31 March to the early morning of 2 April (in UTC time)

So these are all circling around Easter, more or less.  What’s your bet?  😉

 

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Tiangong 1 is coming down

The first Chinese space station has been slowly sinking ever since China publicly acknowledged that control had been lost nearly two years ago, on March 21, 2016.  It’s large enough that portions are expected to survive reentry, but where they will come down is impossible to predict more than a few weeks out from reentry.

Well, we’re now less than a month from reentry; the current prediction is April 3, give or take a week.  A year ago, all that could be said was that it would reenter somewhere under its orbital path, which rules out about a third of the planet.  (It never goes further north or south than 42.7 degrees, so anywhere beyond that is safe.)  Although it could fall anywhere in that band, the current prediction from aerospace.org is that it is most likely to fall at the extreme ends of that.

The band of greatest risk in North America include: most of Oregon, northernmost California, bits of Idaho and Utah, most of Wyoming, a bit of Colorado, a bit of South Dakota, all of Nebraska, a bit of Kansas, all of Iowa, northernmost Missouri, a bit of Wisconsin, the northern half of Illinois and Indiana and the lower peninsula of Michigan, Ohio, the peninsula of Ontario, a bit of West Virginia, Pennsylvania, most of New York, New Jersey, Connecticut, Rhode Island, Massachusetts, part of New Hampshire, and part of Vermont.

In South America, the greatest risk is in a strip of Chile and Argentina.

In Europe, the greatest risk is in Portugal, Spain, Italy, Greece, Croatia, Serbia, Bosnia & Herzegovina, Montenegro, Kosovo, Macedonia, Albania, Bulgaria, a bit of Romania, and Turkey (including the Bosporus).

In Asia, the greatest risk is in Turkey, Armenia, Azerbaijan, a tiny bit of Iran, Turkmenistan, Uzbekistan, Kyrgyzstan, Kazakhstan, Afghanistan, China (including of course the launch site in Jiuquan), a bit of Mongolia, North Korea, and Japan.

Africa is completely within the risk area, but does not touch the areas of greatest risk.

Australia’s island of Tasmania is in the southern greatest risk band, as is most of New Zealand’s North Island and part of the South Island.

The good news is that the vast majority of these bands are still over ocean, and statistically, you are a million times more likely to win the Powerball jackpot than you are to be hit by debris.  Personally, I rather hope it reenters someplace where GOES-East can see it.  The role of GOES-East is currently being filled by one of NOAA’s newest satellites, and it’s got the fastest refresh rate of any geosynchronous spacecraft (well, apart from the new GOES satellite that launched last week; that one has all the same features but isn’t yet in service).  It would be wonderful to get some useful data on the behavior of reentering spacecraft.  As LEO becomes increasingly cluttered, that knowledge becomes progressively more urgent.

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Starman flies on to 20th magnitude

The new observation record stands at 3.2 million km, acquired with the 0.4 meter telescope at the McCarthy Observatory in Connecticut, and is now close to magnitude 20, dimming with distance from both Earth and Sun.   Realistically, if it weren’t for the attached Falcon upper stage, it would have long since faded to invisibility, but it will be interesting to see how long it can be visibly tracked.

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