A 6.3-ton NASA science satellite, decommissioned in 2005, is expected to plunge into Earth's atmosphere later this month, breaking up in a shower of debris. Experts said today they expect 26 components, the largest weighing more than 330 pounds, to survive re-entry heating to hit the surface somewhere between 57 degrees north and south latitude.

But a NASA space debris expert said the threat to the public is minimal and that statistically, the odds are good the debris will land in an ocean or some other sparsely populated area.

"We looked at those 26 pieces and how big they are and we've looked at the fact they can hit anywhere in the world between 57 north and 57 south and we looked at what the population density of the world is," said Nick Johnson, chief scientist with NASA's Orbital Debris Program at the Johnson Space Center in Houston.

"Numerically, it comes out to a chance of 1 in 3,200 that one person anywhere in the world might be struck by a piece of debris. Those are obviously very, very low odds that anybody's going to be impacted by this debris."

The centerpiece of a $750 million mission, the Upper Atmosphere Research Satellite, or UARS, was launched from the shuttle Discovery in September 1991. The solar-powered satellite was designed to address a wide variety of atmospheric questions, including the depletion of Earth's ozone layer 15 to 30 miles up, a trend blamed on the release of man-made chemicals called chlorofluorocarbons, or CFCs, used in refrigerants, foam products, and various solvents.

The long-lived satellite was decommissioned in 2005 and one side of its orbit was lowered using the last of its fuel to hasten re-entry. No more fuel is available for maneuvering and the satellite's re-entry will be "uncontrolled."… Read more

Almost 20 years to the day after it was launched into space to collect data on Earth's atmosphere and interactions with the sun, NASA's Upper Atmosphere Research Satellite is coming back home--in pieces--and there's a higher than normal chance one of them will hit someone.

But before you run to grab your diamond and titanium alloy umbrella that I know you have somewhere in the back of the hall closet for just such an occasion, it's important to note that there's only a 1 in 21 trillion chance that a piece of the space junk will hit you specifically, according to an AP report. A NASA scientist apparently told the AP that there is a 1 in 3,200 chance that a piece of the satellite will hit someone on Earth, which is much higher than the 1 in 10,000 threshold NASA has adopted as an acceptable risk. That rule was put in place after the UARS satellite was launched in 1991.

CNET attempted to confirm the figure, but NASA's East Coast media headquarters is closed for the day. We've reached out through other channels, but did not immediately receive a response. I called U.S. Strategic Command at Vandenberg Air Force Base in California, which also houses the Joint Space Operations Center that "works around the clock detecting, identifying, and tracking all manmade objects in Earth orbit, including space junk," according to a NASA release.

A communications officer there told me that she believed NASA had worked with another agency to come up with a risk model for the UARS re-entry. NASA often uses software called--in typical NASA naming style--ORSAT, for Object Re-entry Survival Analysis Tool, to figure these sorts of things out.

Point is, NASA says in a posting on its Web site, there's a very small risk of a piece of UARS damaging anything or anyone.… Read more

The failure of an unmanned Russian Soyuz booster during launch last week has thrown a wrench into International Space Station operations, with upcoming fights to and from the lab complex facing delays that likely will result in extended operations with a reduced crew of three, a senior NASA manager said today.

During the launch of an unmanned Progress supply capsule atop a Soyuz booster last Wednesday, a sudden loss of pressure downstream of a turbo-pump in the third-stage engine resulted in a computer-commanded shutdown 5 minutes and 20 seconds after liftoff from the Baikonur Cosmodrome in Kazakhstan.

The Progress capsule, … Read more

The upper stage of a Soyuz-U booster carrying an unmanned Russian Progress supply ship malfunctioned and shut down just over five minutes after launch today in Kazakhstan, sending 2.9 tons of space station supplies and equipment crashing back to Earth, NASA officials said.

It was the first post-shuttle launch to the lab complex. Officials said they believe the ship came down in the Altai Republic, part of the Russian Federation, near the border with Mongolia.

It was the second failure in a row for the Russian space program after the Breeze-M upper stage of a more powerful Proton rocket … Read more

KENNEDY SPACE CENTER, Fla.--NASA's $2.4 billion Mars Science Laboratory has completed an exhaustive series of functional tests to verify the car-size rover's readiness for launch in November on an eight-and-a-half-month voyage to the Red Planet and a dramatic rocket-powered "sky crane" descent to the surface, officials said today.

Engineers now plan to carefully fold up the rover's robot arm, camera mast, wheels, and suspension so it can be packed inside a protective aeroshell that, in turn, will be attached to the bottom of a rocket-powered descent stage. The entire spacecraft then will be … Read more

KENNEDY SPACE CENTER, Fla.--A powerful United Launch Alliance Atlas 5 rocket roared to life today and launched NASA's solar-powered Juno space probe on a five-year voyage to Jupiter, the first step in a $1.1 billion mission to look for clues about the origins of the solar system in the hidden heart of its largest planet.

"What we're really going after are some of the most fundamental questions of our solar system--how Jupiter formed, how it evolved, what really happened early in the solar system that eventually led to all of us and the terrestrial planets," said Scott Bolton, the principal investigator. "These are really basic questions: who are we, where did we come from, how did we get here?

"We're kind of going after this recipe of how planets are made. We're getting the ingredients of Jupiter, we're going to understand what the structure is like inside, how was it built, and that will give us guidance as to what happened in that early time that eventually led to us."

The towering 197-foot-tall Atlas 5, equipped with five solid-fuel strap-on boosters for extra power, ignited with a ground-shaking roar at 12:25 p.m. EDT, generating 2.5 million pounds of thrust and instantly pushing the spacecraft away from launch complex 41 at the Cape Canaveral Air Force Station. It was only the second launch of a five strap-on Atlas 5, the most powerful version offered by United Launch Alliance.

Liftoff was delayed 51 minutes to resolve two technical issues and to make sure a boat that strayed into the launch danger zone cleared the area.

Climbing away atop a brilliant plume of fiery exhaust, the rocket accelerated through the sound barrier 34 seconds after liftoff, arcing away to the east and putting on a spectacular lunchtime show for tourists and area residents. The strap-on boosters burned out and peeled off about a minute later and the first stage shut down and fell away as planned four and a half minutes after launch.

The rocket's hydrogen-fueled Centaur upper stage then carried out a six-minute burn to boost the spacecraft into a temporary parking orbit. A second nine-minute Centaur firing 31 minutes later accelerated Juno to 25,000 mph, or 7 miles per second--interplanetary escape velocity--and three minutes later, the 4-ton spacecraft separated from the Centaur to fly on its own.… Read more

A NASA spacecraft in orbit around Mars has detected signs of what appear to be seasonal flows of salty water on the surface of the red planet during warmer summer months, an "eye-opening" finding that could help scientists target future missions to look for signs of microbial life in the frigid soil, researchers said today.

"We have found repeated and predictable evidence suggesting water flowing on Mars," said Michael Meyer, lead scientist with NASA's Mars Exploration office.

The Mars Reconnaissance Orbiter, launched in 2005 and conducting continuous observations of Mars since November 2006, spotted the … Read more

Boeing will use United Launch Alliance Atlas 5 rockets for initial test flights of the company's proposed CST-100 manned spacecraft, a seven-seat capsule being developed for commercial missions to and from government and private-sector space stations in low-Earth orbit, company officials announced today.

John Elbon, vice president and program manager of Boeing commercial crew transportation systems, said four test flights of the CST-100 spacecraft are envisioned, assuming continued NASA funding, including an on-the-launch-pad abort test in 2014 that will not require a booster.

The other three flights will use a version of the Atlas 5 that includes one solid-fuel … Read more

Four years after launch from Cape Canaveral, NASA's ion-drive Dawn spacecraft is finally in orbit around the asteroid Vesta, studying the second largest body in the rubble-strewn belt between Mars and Jupiter in unprecedented detail. Pictures released today show a strangely tortured world with huge parallel grooves separating the heavily cratered northern hemisphere from smoother terrain in the south dominated by the chaotic remnants of a catastrophic impact.

"These photos have been already a great revelation to the team about what the surface is like," Christopher Russell, the mission's principal investigator, told reporters today. "We … Read more