Watch Out

[oskar]

Nasa satellite to fall to earth on Friday, showering debris
A defunct NASA science satellite is expected to fall back to Earth on Friday, showering debris somewhere on the planet although scientists cannot predict exactly where, officials said
The 6.5-ton Upper Atmosphere Research Satellite, or UARS, was carried into orbit during a space shuttle mission in 1991. It operated for 14 years, collecting measurements of ozone and other chemicals in the atmosphere.
Since completing its mission in 2005, UARS has been slowly losing altitude, tugged by Earth's gravity. On Friday, the 35-foot-long, 15-foot diameter (10.6-metres long, 4.5-metres diameter) satellite is expected to plunge into the atmosphere, NASA reported on its website.
While most of the spacecraft will be incinerated, scientists expect up to 26 pieces, with a combined mass of about 1,100 pounds (500kg) to survive the fiery re-entry and fall down somewhere on Earth.
The satellite's orbit passes over most of the planet, from as far north as northern Canada to the southern part of South America.
NASA said the chance a piece of UARS debris will strike a person is about one in 3,200. The debris will mostly likely fall into an ocean or land in an uninhabited region of Earth
Satellites as large as UARS re-enter Earth's atmosphere about once a year.
NASA said there have been no reports of any deaths or injuries to people from falling debris.
The largest chunk of wreckage from UARS is expected to be about 331 pounds (151kg), says Nicholas Johnson, chief scientist of NASA's Orbital Debris Program office at the Johnson Space Center in Houston.
As of Sunday, UARS was in a 133-mile by 149-mile (215-km by 240-km) high orbit around Earth. Re-entry is expected some time on Friday, although it could happen as early as Thursday or as late as Saturday

If you want you can keep track of it here
http://www.n2yo.com/?s=21701
Cheers Oskar

[Darrell]

I find this situation totally unacceptable!!!!! NASA should employ a self destruct device that reduces low orbit satellites to smithereens when about to terminate orbit. Expect a gigantic law suit the day one of these crashing satellites causes real damage or kills someone.

[Carol Nistri]

I think that was discussed once Darrell,seems someone came up with the notion that if they did have a self destruct on one of these gizmos then those bits and pieces would make matters worse.

[Darrell]

Originally Posted by Carol Nistri

I think that was discussed once Darrell,seems someone came up with the notion that if they did have a self destruct on one of these gizmos then those bits and pieces would make matters worse.

The smaller the pieces, the more likely they will burn up on reentry. A high explosive plastic charge of about one half pound C4 should significantly reduce size and integrity of a satellite weighing less than half that of a small automobile. And the composite materials that make up most aerospace structures these days should fragment very nicely.

Perhaps you are confusing this with the idea of shooting down comets and meteoroids prior to entering the atmosphere. In that case, exploding the object would be worse because all the pieces would still be super large and massive, creating a shotgun effect at the impact sites.

[oskar]

NASA space junk experts have refined the forecast for the anticipated death plunge of a giant satellite, with the U.S. space agency now predicting the 6 1/2-ton climate probe will plummet to Earth around Sept. 23, a day earlier than previously reported.

The defunct bus-size spacecraft is NASA's Upper Atmospheric Research Satellite (UARS), which launched in 1991 and was shut down in 2005 after completing its mission. The satellite was expected to fall to Earth sometime this year, with experts initially pegging a weeks-long window between late September and early October, then narrowing it to the last week of this month.

That window, NASA now says, has been trimmed to just three days.

"Re-entry is expected Sept. 23, plus or minus a day. The re-entry of UARS is advancing because of a sharp increase in solar activity since the beginning of this week," NASA officials wrote in a status update today (Sept. 16). The projection is a day earlier than a previous forecast released by NASA yesterday.

NASA spokeswoman Beth Dickey confirmed with SPACE.com earlier today that the reason UARS is expected to fall early in its re-entry window is because of the sharp uptick in solar activity. Solar effects from the sun can create an extra drag on satellites in space because they can heat the Earth's atmosphere, causing it to expand, agency officials have said. [Photos: Space Debris & Cleanup Concepts]

Where will UARS fall?

But exactly where the UARS spacecraft will fall is still unknown.

NASA expects at least 26 large pieces of the massive satellite to survive the scorching temperatures of re-entry and reach Earth's surface. Titanium pieces and onboard tanks could be among that debris, but the UARS satellite carries no toxic propellant (NASA used up all the fuel in 2005).

The debris is expected to fall over a swath of Earth about 500 miles (804 kilometers) long, NASA officials said. [Video: Where Could UARS Satellite Debris Fall?]

There is a 1-in-3,200 chance of satellite debris hitting a person on the ground, odds that NASA says are extremely remote. Outside experts agree.

Constant satellite watch

NASA officials expect the UARS satellite to fall over a region somewhere between the latitudes of northern Canada and southern South America, which leaves a vast swath of the world open as a possible re-entry point. About 75 percent of the Earth's surface is covered in water, which makes an ocean splashdown likely, NASA and experts have said.

NASA and the Joint Space Operations Center of U.S. Strategic Command at Vandenberg Air Force Base, Calif., are keeping a close watch on the falling satellite, but will only be able to pinpoint its actual crash zone to within about 6,000 miles (10,000 km) about two hours before re-entry.

As of Thursday, the UARS satellite was flying in an orbit of between 143 and 158 miles (230 to 255 km) above Earth. That orbit is dropping lower each day, NASA officials said. [Infographic: NASA's Falling UARS Satellite Explained]

NASA has advised the public not to touch any debris that may reach the surface, should it be discovered. Instead, the space agency says that anyone who finds satellite debris should contact their local law enforcement agency.

The $750 million UARS mission was designed to measure ozone and other chemical compounds found in Earth's ozone layer in order to better understand how the upper atmosphere affects our planet. It also recorded wind speeds and temperatures in the stratosphere, as well as the energy Earth received from the sun.

This report was updated to reflect new estimates of the UARS re-entry released by NASA after this story first appeared.

http://www.n2yo.com/?s=21701

[Carol Nistri]

Your right Darrell,I was thinking of a meteorite.

[dr wu23]

Originally Posted by Darrell

I find this situation totally unacceptable!!!!! NASA should employ a self destruct device that reduces low orbit satellites to smithereens when about to terminate orbit. Expect a gigantic law suit the day one of these crashing satellites causes real damage or kills someone.

You mean like the girl in Dead Like Me who was killed by a toilet seat from an orbiting space station..?

[Darrell]

Probability is valued differently in different situations. The probability of 1/10 is too low for winning the lottery; yet the probability of 1/1,000,000 is too large for getting hit by a bus-size satellite falling to earth from low orbit. You know?