As NASA prepares for the first test flight of its next-generation Orion crew capsule, meant to someday take astronauts to Mars, scientists are carefully gauging the risks -- and they are considerable.
Set for this week, the Exploration Flight Test-1 launch will test Orion's key systems as a crucial test of the capsule that may take humans beyond Earth to asteroids and to the Red Planet.
"Everyone is very excited about this mission," said NASA spokeswoman Stephanie Schierholz. "Orion's flight test is a critical step on NASA's journey to Mars."
Although this test will be an unmanned mission, that doesn't mean there aren't risks to people involved in it, NASA acknowledges, especially those handling the recovery effort when the capsule returns from space to splash down in the Pacific Ocean.
"The environment in the open ocean is a hazardous environment in and of itself," said Jeremy Graeber, recovery director for the test flight. "Nominally, the vehicle coming down should not pose any threats to the recovery forces, but it's a test flight, so there are systems that we are not 100 percent sure we know what position they're in once we're splashed down."
Those systems include the spacecraft's propellant, plus ammonia and some "radiating elements" used in Orion's telemetry systems, he explained, but safeguards are in place to ensure everyone handling the spacecraft remains safe, he said.
Of course the spacecraft itself will face some risks and extreme conditions in its first flight, set for Dec. 4, which will see it lifted by a United Launch Alliance Delta 4 Heavy rocket into two orbits of the Earth at as distance of about 3,600 miles.
After about 4.5 hours, Orion will plummet into the Earth's atmosphere at high speed and put its heat shield -- the largest of its kind ever created -- to the test.
"Orion will reenter the atmosphere at speeds of 20,000 mph and experience temperatures of about 4,000 degrees Fahrenheit before splashing down in the Pacific Ocean about 600 miles southwest of San Diego," Schierholz said.
Assuming the heat shield does its job, then it's up to Orion's giant parachute system to further slow its velocity in preparation for splashdown.
NASA will be watching the test closely to gather data to fine-tune Orion's design and to reduce any possible risk to the astronauts that will one day fly in it, Schierholz said.
"The flight test basically is a compilation of the riskiest events we'll see when we fly astronauts in Orion," he said. "The test will stress systems critical to safety, including the heat shield, parachutes, avionics and attitude control, to help us learn as much as possible before Orion carries astronauts on missions to explore an asteroid and on the journey to Mars."
"The best testing we can do of Orion is to fly it in space."
