X-37B Might Not be Spying on China’s Space Station

So remember the Internet hubbub last week when the BBC reported that the Air Force’s X-37B space plane may well be spying on China’s new space station, Tiangong-1, since their orbits are very close? Well, it turns out that the source behind that story, Spaceflight, the magazine of the respected British Interplanetary Society ignored one key fact; the X-37B and the Chinese space station whip past each other at insanely fast speeds when their orbits intersect, points out James Oberg, a former member of the organization that came up with the claim over at Tech Talk.

The American plane’s orbit is at a steep angle with respect to that of the Chinese space station. When the two vehicles pass, they do so at speeds of up to 8000 meters per second, making it practically impossible for one to gather intelligence on the other.

Both orbits are tilted to the equator at about the same amount, 43 degrees, and both fly about 300 kilometers high. But that is as far as the resemblance goes. According to aBBC account of the article, to be published this weekend in the 55-year-old journal Spaceflight, the author and all the editorial reviewers forgot one additional parameter that you need to specify relationships between orbits. This is the point on the equator where the orbit begins its pass over the northern hemisphere: in technical terms, the RAAN.

That information is readily available for the X-37B and Tiangong-1, and it show the two satellites are orbiting in nearly perpendicular planes. The difference in RAAN is about 95 degrees, and combined with their orbital inclinations, spherical trigonometry shows the two planes are tilted 60 degrees apart.

As others have noted, the X-37Bs orbit places it in a good position to spy on the Middle East. The image above shows the X-37Bs orbit in yellow and Tiangong-1’s orbit in red. Image via Tech Talk.

  • crackedlenses

    “X-37B Might Not be Spying on China’s Space Station”

    Remind that this isn’t a parody making fun of defense blogs……

  • Skyepapa

    On a slightly tangential note: It’s interesting that Sinolab’s orbit carries it right over DC with every circumference…

    • blight

      Well, certainly the Northeast, but it looks like New England is getting more scrutiny than DC.

    • kim

      My first thought too….

  • nary

    Perhaps its an ultra-sensitive monitor for global warming…

  • Lance

    Course not this is a test craft NOT a spy plane.

  • Dfens

    As long as the inclination is the same, the rest is just timing. Hell, it’s not like it is such a damn big deal to change the inclination plane. The shuttle did it every time it went to the space station. Thanks to the “partnership” with the Russians we put the station in a 52 degree orbit instead of 23 degrees like we should have. Yeah, but why use it as a staging point for a lunar or interplanetary mission anyway? There’s nothing of value on any other moons, asteroids, or planets other than Earth. NASA has already spoken on that one, and it wasn’t just propaganda to cover the failures of the shuttle program or an astonishing lack of imagination, just so you know.

  • anonimouse9

    Or Richard Branson.

  • gt350

    It looks to me China is flying over NV–I wounder why?

  • jhouse

    what if it were deploying mini-satellites that could maneuver to any orbit or trajectory and do their thing and return to dock in the cargo bay virtually undetected?