A U.S. spy satellite has left orbit and is currently descending to Earth. It has lost power and cannot be controlled and is expected to hit in late February/early March.
Now I understand that there are many factors that go into an object staying in orbit (namely gravity and things that could disrupt gravity), but this satellite was launched in December 2006, and January 2008 seems rather soon for it to have already messed up. According to one AP article, “Initial estimates were that the satellite would take years to degrade and re-enter the atmosphere.” I think “years” gives them a lot of leeway to begin with, but it’s barely over a year, so they entirely missed the mark.
Skepticism aside, here are some facts:
- “In the past 50 years of monitoring space, 17,000 manmade objects have re-entered the Earth’s atmosphere.” (AP 1/29)
- “Where it lands will be difficult to predict until the satellite falls to about 59 miles above the Earth and enters the atmosphere. (AP 1/30)
- “the satellite was not all that large to begin with—estimated at 13 feet by 16 feet—and it will break up on reentry; any pieces likely to survive the descent will probably be small. And the odds are they will come down somewhere in the geographic feature that covers three-quarters of the planet: the oceans.” (NY Times blog, 1/30)
- “It is fairly common for satellites to drop out of orbit and enter Earth’s atmosphere, but most break up before they reach the surface, [said Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics and an analyst of various government space programs.] Such incidents occur every few months, and it is often difficult to control the satellite’s trajectory or its re-entry into the atmosphere. The debris, if any survives the fiery descent, typically lands in remote areas and causes little or no harm.” (NY Times, 1/27)
- a group of amateur satellite watchers has compiled a list of “memorable decays” (re-entries) here