The launch teams that will work together Dec. 4 to launch the Orion spacecraft practiced the countdown today that will included fueling the core stages of the Delta IV Heavy rocket that will lift Orion on its unmanned flight test. Working in control rooms at Cape Canaveral Air Force Station in Florida, countdown operators followed the same steps they will take on launch day. The simulation also allowed controllers to evaluate the fuel loading and draining systems on the complex rocket before the Orion spacecraft is placed atop the launcher next week.
The Delta IV Heavy – seen on the left as it was when rolled to the pad – is made up of three core stages, each powered by cryogenic liquid oxygen and liquid hydrogen, some of the coldest materials known. The second stage of the rocket also uses the same cryogenic propellants. During the actual flight test, Orion will be launched on a two-orbit mission that will reach 3,600 miles above Earth and take the spacecraft more than 60,000 miles before Orion’s heat shield is tested with a high-speed reentry through the atmosphere. That portion of the test will give engineers what they need to make sure the heat shield can withstand the searing conditions of bringing back astronauts from missions into deep space destinations including, eventually, Mars.