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| Space on Sep 24, 2011

UARS satellite reenters atmosphere over Pacific Ocean

UARS penetrated the atmosphere over the Pacific. No debris has been found. There are no reports of injury or property damage. Hoax videos are circulating.

UPDATE SEPTEMBER 24, 6 PM (11 UTC)

Here is the official word from NASA about the UARS satellite, which made an uncontrolled reentry into Earth’s atmosphere on September 24, 2011:

Data indicates the satellite likely broke apart and landed in the Pacific Ocean far off the U.S. coast. Twenty-six satellite components, weighing a total of about 1,200 pounds, could have survived the fiery re-entry and reach the surface of Earth. However, NASA is not aware of any reports of injury or property damage.

That is surely a relief to many.

NASA’s official UARS page, where updates will appear, if there are any

At a NASA teleconference at 2 p.m. EDT on September 24, NASA released this map of the possible re-entry point of the UARS satellite, with the green circle above indicating the point at 31 N latitude and 219 E longitude. (NASA)

So apparently there was no debris field in western Canada.

Also, don’t be fooled by the fake vidoes circulating on the Internet, supposedly showing UARS as it falls, including the one I found and questioned earlier today. Yep, it’s fake. There’s also this one, which looks remarkably similar.

But if you’re going to watch just one fake – and remember this is a hoax, it’s just too good to be true – check out this amazing Portuguese video. It can’t be real, but it has some realistic elements, like the little pops and flares along the path of the (giant!) body flaming along through the night. One night while standing outside at Kitt Peak National Observatory near Tucson, an astronomer friend and I saw a flaming body enter the atmosphere that popped and flared in much this same way – although it was much, much farther away, of course. We both agreed it looked like space debris because of those pops, which probably occur when a particular kind or density of metal in an artificial satellite (as opposed to a natural meteor) meets its fiery end.

If you want to some real pictures of what UARS looked like in the day before it reentered, try SpaceWeather.com, which rocks as always at providing the best images taken by sky photographers from around the world. There’s this one and this one. Quite a difference from the (hoax) Portuguese video above, eh?

UPDATE SEPTEMBER 24, 5 AM CDT (10 UTC)

The Joint Space Operations Center at Vandenberg Air Force Base in California says the bus-sized Upper Atmosphere Research Satellite (UARS) satellite plunged to Earth over the Pacific late Friday night (early Saturday in the eastern U.S. time zone, Europe and Africa).

There are unsubstantiated reports of debris falling over Okotoks, a town 20 miles (30 km) south of Calgary in western Canada. Locals in Okotoks are reporting the discovery of wreckage, including a large piece that left a substantial crater and a possible debris field extending to the northeast of there. There is also a video on YouTube supposedly showing falling debris. I’m not sure I believe the video is real, which makes me question the other reports … but time will tell.

NASA says UARS re-entry took place between 10:23 p.m. CDT September 23 and 12:09 a.m. CDT September 24 (3:23-5:09 UTC September 24). The satellite penetrated the atmosphere over the Pacific Ocean. NASA is working now to substantiate reports of falling debris.

News from NASA: International Space Station will not go unmanned in November

The video below – made some days ago – shows an animation of UARS leaving orbit.

UARS was 35 feet long and 15 feet wide (about 12 by 5 meters). It was among the largest spacecraft to reenter Earth’s atmosphere and make an uncontrolled descent, although it was much smaller than NASA’s 85-ton Skylab, which fell in 1979.

Russia’s last space station, Mir, was even heavier at 150 tons. It made a guided descent in 2001 and also crashed into the Pacific Ocean.

According to Reuters, NASA now plans for the controlled re-entry of large spacecraft, but it did not when UARS was designed.

UPDATE SEPTEMBER 23, 6 PM CDT (11 UTC)

As of 6 p.m. CDT on September 23, the orbit of UARS was 90 miles by 95 miles (145 km by 150 km). It’s coming in faster now. According to NASA, re-entry is expected between 10 p.m. CDT on September 23, and 2 a.m. CDT on September 24 (3 a.m. to 7 a.m. UTC). During that time period, NASA says, the satellite will be passing over Canada, Africa and Australia, as well as vast areas of the Pacific, Atlantic and Indian oceans. NASA says the risk to public safety is remote.

UPDATE SEPTEMBER 23, 9:45 AM CDT (14:45 UTC)

Center for Orbital and Reentry Debris Studies on reentry time for UARS: September 23 @ 7:58 CDT (September 24 @ 00:58 UTC) ± 7 hours.

NASA on reentry time for UARS agrees: Re-entry is expected late Friday, Sept. 23, or early Saturday, Sept. 24, Eastern Daylight Time.

NASA says that solar activity is no longer the major factor in the satellite’s rate of descent, and that the satellite’s orientation or configuration apparently has changed, and that is now slowing its descent. According to NASA, there is a low probability any debris that survives re-entry will land in the United States, but the possibility cannot be discounted because of this changing rate of descent. It is still too early to predict the time and location of re-entry with any certainty, but NASA expects predictions to become more refined throughout the day today.

Don’t miss the video below! It’s an actual video os UARS in orbit, taken September 15, 2011.

This video shows the tumbling and clearly uncontrolled motion of the UARS satellite. It’s from Thierry Legault, a wonderful astrophotographer, who obtained this footage of UARS with his 14-inch telescope in northern France, when the satellite at an altitude of 250 kilometers (155 miles) above Earth. That’s in contrast to UARS current altitude of approximately 160 kilometers (100 miles), as of 9:30 a.m. EDT (14:30 UTC) on September 23. In the video, you can see UARS body and its solar arrays.

UPDATE SEPTEMBER 22, 2011 09:01 PM CDT (SEPTEMBER 23 1:01 UTC)

The orbit of UARS was 110 mi by 115 mi (175 km by 185 km). Re-entry is possible sometime during the afternoon or early evening of September 23, Eastern Daylight Time.

UPDATE SEPTEMBER 22, 2011 10:06 AM CDT (15:06 UTC)

Predicted Reentry Time: September 23, 2011 5:07 p.m. CDT (22:07 UTC) ± 9 hours.

Real time satellite tracking for UARS

UARS re-entry twitter feed

UARS reentry zone. Predicted reentry time: 23 SEP 2011 22:07 UTC ± 9 hours (as at 22 SEP 11:06UT)

SEPTEMBER 22, 2011 5 CDT (10 UTC) NASA has now refined its prediction slightly for when this bus-sized satellite will fall to Earth. The predicted re-entry is now scheduled for 3 p.m. CDT (20:36 UTC) on September 23, 2011, plus or minus 20 hours.

It has been known for some time that the 6.5-ton satellite would leave orbit and return to Earth. Experts initially suggested a weeks-long window between late September and early October, then narrowed the window to the last week of this month. Later, NASA trimmed the interval to a three-day period centered on September 23.

The 20-year-old satellite – the Upper Atmosphere Research Satellite (UARS) – will make an uncontrolled re-entry through the Earth’s atmosphere. Pieces of the 6.5-ton satellite are expected to survive the fiery plunge and hit our planet, although no one knows exactly where.

The chances of being hit by the falling UARS satellite are small. Nick Johnson, chief scientist with NASA’s Orbital Debris Program, told Universe Today last week:

Numerically, it comes out to a chance of one in 3,200 that one person anywhere in the world might be struck by a piece of debris.

When you think about the seven billion people on Earth today, you see how vanishingly small the probability of being struck really is. After all, most of Earth is ocean, so chances are UARS will go from the fires of re-entry directly to a watery grave in the ocean depths. It’s also important to note that no injury has ever been caused by orbital debris during the half-century that we humans have been placing objects in Earth orbit.

Tongue-in-cheek debris map for UARS re-entry developed by The WeatherSpace.com

NASA says the satellite is likely to begin re-entry on September 23, 2011, give or take a day. Hurtling at five miles (eight kilometers) per second, they say it could land anywhere between 57 degrees N. latitude and 57 degrees S. latitude – basically, most of the populated world.

The satellite was launched in 1991 by the space shuttle Discovery. Designed to operate for three years, six of its ten instruments are still functioning, according to NASA’s UARS page. However, the satellite was officially decommissioned in 2005, at the same time that other satellites took over its work.

This isn’t the first time a massive satellite left orbit and made an uncontrolled re-entry back to Earth. In 1979, Skylab re-entered the atmosphere, causing some nail-biting before it finally struck safely in Australia.

Bottom line: NASA’s UARS satellite made an uncontrolled reentry into Earth’s atmosphere on September 24, 2011. According to NASA, the satellite likely broke apart and landed in the Pacific Ocean far off the U.S. coast. Twenty-six satellite components, weighing a total of about 1,200 pounds, could have survived the fiery re-entry and reach the surface of Earth. However, NASA is not aware of any reports of injury or property damage.

Space debris a growing problem