NASA says satellite will hit Earth Sept 23 US time

September 21, 2011

The US space agency has narrowed down its prediction of when a defunct six-ton satellite will crash back to Earth, saying on Wednesday that it is expected to land on September 23, US time.

"The time reference does not mean that the satellite is expected to re-enter over the United States. It is simply a time reference," NASA said on its website.

"Although it is still too early to predict the time and location of re-entry, predictions of the time period are becoming more refined."

NASA had previously said the satellite could hit Earth as early as Thursday, September 22 or as late as Saturday, September 24.

All but 26 pieces of the Upper Atmosphere Research Satellite (UARS) are expected to burn up on re-entry into Earth's atmosphere, but where exactly they will land remains a mystery.

Orbital debris scientists say the pieces will fall somewhere between 57 north latitude and 57 south latitude, which covers most of the populated world. The debris footprint is expected to span 500 miles (800 kilometers).

UARS is the biggest to come back in three decades, after Skylab fell in in 1979.

The risk to human life and property from UARS is "extremely small," NASA said, adding that in 50 years of no one has ever been confirmed hurt by falling .

More frequent updates are scheduled for 12, six and two hours before it lands.

But even at two hours out, debris trackers will not be able to predict landing with an accuracy greater than 25 minutes of impact, or within a potential span of 7,500 miles (12,000 kilometers), NASA said.

"Part of the reason it is so uncertain is the spacecraft itself is rather unwieldy looking and it tumbles and we can't predict exactly how it is going to be tumbling," said Mark Matney, an expert at NASA.

"Even as it tumbles that could change exactly where it is going to land."

Explore further: Space junk safely passes space station; crew OK (Update 2)

Related Stories

Earth to satellite: When will you hit -- and where?

September 20, 2011

(AP) -- NASA scientists are doing their best to tell us where a plummeting six-ton satellite will fall later this week. It's just that if they're off a little bit, it could mean the difference between hitting Florida or ...

Recommended for you

Dense star clusters shown to be binary black hole factories

July 29, 2015

The coalescence of two black holes—a very violent and exotic event—is one of the most sought-after observations of modern astronomy. But, as these mergers emit no light of any kind, finding such elusive events has been ...

Image: Hubble sees a dying star's final moments

July 31, 2015

A dying star's final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star's demise is still quite ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Skepticus
not rated yet Sep 22, 2011
UARS can do JWST and America a huge favor by taking out the entire current crop of Congress idiots.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.