This is an archived article that was published on sltrib.com in 2005, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
This time around, NASA is counting on a softer landing.
As crews prepare for the Stardust mission's sample return probe to land in Utah's west desert next month, they hope to avoid having to scrape a craft off the desert floor again.
In September 2004, Hollywood stunt pilots waited in helicopters to snag another incoming NASA probe in midair as it floated over the U.S. Air Force's Utah Test and Training Range.
Instead, the trained helicopter crews became spectators as the Genesis mission's probe - carrying bits of the sun - hurtled into the mud at nearly 200 mph. Investigators blamed the 2004 crash on gravity sensors that were installed backward. Had they been properly installed, they would have triggered a parachute.
When NASA lands the Stardust probe in Utah on Jan. 15, officials are confident they will avoid the same parachute problem.
"We feel very comfortable that we don't have any errors like the reversed [gravity] sensor for Genesis," said Thomas Duxbury, project manager for NASA's Stardust mission.
While Genesis collected solar particles coming off the sun, Stardust is hauling back bits of a comet. The spacecraft in 2004 flew through the tail of the Wild 2 comet to collect microscopic debris streaming from the nucleus of the flying iceball.
Researchers designed Genesis and Stardust to collect material from the earliest building blocks of our solar system and return to Earth.
Genesis researchers seek a better understanding of the composition of the sun. This material could tell more about the origins of the solar system.
For Stardust, scientists believe comets preserve the solar system's original building material. Details gleaned from these samples could give new insight into the processes involved in forming the sun, planets and other objects in the solar system.
Despite the Genesis crash, scientists managed to salvage much of the solar science from the Genesis collector equipment. The delicate nature of the Genesis collector plates, where solar particles became embedded, prompted engineers to design the softest possible landing.
Hollywood stunt pilots spent several years training to catch the Genesis probe's parachute in midair to gently ease it to the ground. NASA envisioned a spectacular daytime catch, which instead turned to disaster when the parachute failed to open.
Expect less glitz for Stardust, which will land at 3 a.m. Helicopters will be ready, but they will fly out to the probe after it has landed. Stardust's collector material is sturdier than that of Genesis, meaning it can handle a parachute landing.
A major reason for optimism about Stardust's gravity sensors is the thorough review process scientists and engineers undertook during the mission. Design plans, photographs and reports indicate the sensors are properly installed and that everything else is up to specifications.
"There were no smoking guns," Duxbury explained, "everything was designed and implemented and tested correctly."
The gravity sensors are designed to detect the force of gravity as the probe tears through the atmosphere. When "G" forces reach a certain level, a circuit should prompt the parachute to deploy.
Everything about Stardust appears to have been built as specified.
"Now does that mean it's going to work?" asked Duxbury. "That's another question."
Stardust has been touring the inner solar system since its 1999 launch. Components that have sat dormant for seven years need to operate properly for a smooth landing. In many cases during landing, this will be the first and only time the components will be activated.
Donald Brownlee, Stardust's principal investigator from the University of Washington, said the launch and comet fly-by carried greater risk for failure than what will happen in the home stretch.
"Frankly, the return is one of the least uncertain aspects of the whole mission," he said.
About a day before landing, Stardust team members release the return probe from the main spacecraft.
"We aim this thing at Utah and we release the capsule," he said. "It's all on its own."
And if there is a problem, mission controllers can divert the entire spacecraft into a new orbit before ejecting the capsule. The next landing window would take place in about three years.
While waiting for the landing, scientists and engineers are going through various worst-case scenarios and how they would respond. After the spacecraft releases the return probe, all the Stardust team can do is watch and wait.