A US spaceship designed to fly astronauts beyond Earth's orbit for the first time since the 1960s-era Apollo moon program is due to blast off on Thursday in a long-awaited debut test flight.
An unmanned version of an Orion capsule, built by Lockheed Martin for NASA, will lift off aboard a Delta 4 Heavy rocket at 7:05 a.m. EST/1205 GMT from Cape Canaveral Air Force Station in Florida, officials said on Tuesday.
Thursday's test run will be followed in four years with the launch of a second Orion capsule, also unmanned, on the debut flight of NASA's still-under-development Space Launch System rocket. That flight will send the capsule around the moon.
Orion's third flight, slated for around 2021, is expected to include astronauts.
Eventually, NASA intends to use Orion and the SLS rocket to send crews to Mars, the ultimate goal of the US human space program. Astronauts have not ventured beyond Earth's orbit since the 1969-1972 Apollo moon program.
"Thursday is a huge day for us," NASA Orion Program Manager Mark Geyer told reporters. "Part of me hopes that everything is perfect, but really on a flight test like this ... we want to discover things that are beyond our modeling capability and beyond our expertise so we learn (about) it and fix it."
The rocket, built and flown by United Launch Alliance, a joint venture of Lockheed Martin and Boeing, will catapult the capsule as far as 3,600 miles (5,800 km) from Earth so it can slam back into the atmosphere at a speed of 20,000 miles per hour (32,200 km per hour).
One of the primary goals of the 4-1/2-hour flight is to test how well Orion's heat shield withstands temperatures of about 4,000 Fahrenheit (2,200 Celsius) it will experience during
re-entry.
Another key test comes when the capsule's 11 parachutes deploy to slow its descent to 20 mph (32 kph) so it can gently splash down in the Pacific Ocean for recovery.
NASA wants to reuse the capsule to test an emergency escape system needed in case of an accident during liftoff. Engineers also are eager to retrieve data collected by sensors aboard Orion that will record conditions experienced during Thursday's flight.
