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X-37B

December 2, 2011 by · Comments Off on X-37B 

X-37B, The US Air Force has officially confirmed that the second flight of their X-37B robot spaceplane is on overtime. This small experimental spacecraft, which resembles a car-sized space shuttle, has been in orbit since early March. At the end of November, the spacecraft passed its semi-official endurance limit of 270 days in space.

The USAF had been very quiet about this mission for months, but broke the silence as the deadline approached. We have been told that the X-37B is in good health, and is now flying an extended mission. Exactly when the vehicle will return to Earth remains unclear.

Why stretch the mission beyond its previously advertised endurance level? It’s probably because the true endurance of the spacecraft is known to be much longer. Engineers are conservative, and tend to favor safe numbers in their predictions. The publicized endurance figure is probably fudged with wide safety margins. There’s also the benefit of the previous mission in 2010, which lasted around 224 days.

Data from the spacecraft returned during this first flight, and obtained after its return, probably showed that it was performing better than expected. Earlier predictions of how some of its systems would degrade have probably been found to be inaccurate. The result is a new, better-informed estimate of the endurance for X-37B. How large is the new figure? Beyond closed doors, nobody seems to know.

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