NASA and ATK Aerospace Systems successfully ground-tested the most powerful solid-fuel rocket engine ever in the Utah desert 31 Aug, though the test was conducted under a shadow of uncertainty for future funding.
The five segment demonstration motor-2 (DM-2) roared to life in a two-minute static cold-temperature test, generating 3.6 million lbs of thrust, with NASA and ATK both declaring the test to be "excellent and successful."
Preliminary data indicated this second test of the demonstration motor yielded the chamber and thrust pressures the team was expecting says Alex Priskos, first stage manager for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Ala.
Some changes were made between the first and second motor tests, he says. DM-2 incorporates singular insulation in the aft dome, which is easier and more cost effective to produce, Priskos says, and eliminated some materials obsolescence issues.
It also includes upgraded insulation in nozzle cone, he says. And DM-1 had good seals between the segments. "We couldn't get anything past them," Priskos says. "We intentionally flawed the first barrier this time to get some gases past them and we're very anxious to look at that data."
The DM-2 and its brothers were designed as the first stage of the Ares I rocket to provide the lift-off thrust for the next generation of US manned spaceflight. But President Barack Obama has said he plans to cancel the over-budget Constellation program in which the ATK boosters would be used. Next year's space programme funding is still being hashed out on Capitol Hill.
The current programme of record allows for four demonstration motors and two qualification motors, says Doug Cooke, NASA's associate administrator for exploration systems. DM-3 and DM-4 will focus on optimizing insulation, with DM-3 slated to be a "hot-fire" test and DM-4 a cold test, "which really tests performance and structural limits," he says. The three qualifying motors will be identical to assure repeatability in the manufacture process and performance.
"That was what was in the program of record, that's what we're executing to," Cooke says.
The funds for casting and testing DM-3 have already been allocated, Priskos says, and those on the government and contractor sides of the programme remain optimistic.
"The plan that we have in place concentrates on developing human space flight in the future," Cooke says. "The crew vehicle and heavy lift still being considered. We want to get beyond low Earth orbit. The work done here and the capabilities that are being developed will most certainly contribute to developing that future."
The static rocket motor tests run about $75m each. NASA has already sunk about $1b into the first-stage development of the next-generation boosters, Priskos says.