Alliant Techsystems said in a statement earlier this month that it had "recently demonstrated a critical capability of its liquid oxygen -- LOX/Methane rocket engine by igniting it in a vacuum chamber. The successful ignition test was designed to demonstrate the viability of a LOX/Methane rocket engine for a lunar ascent mission."

"This test engine was designed for 3,500 lbf thrust to bracket the expected thrust range of a lunar ascent engine. The successful vacuum chamber test is the latest in a series of tests that establishes ATK as the industry leader in LOX/Methane rocket engine technology. The company previously test-fired a 7,500 lbf LOX/Methane engine at sea-level," the company said.

ATK said it "expects to conduct additional tests of its LOX/Methane engine technology over a wide range of operating conditions to simulate the environment an operational engine must perform in during a lunar ascent. The data collected from this test series will be instrumental in determining performance parameters and the optimal scale of a flight-weight LOX/Methane engine. The company will conduct these tests at its test facility in Ronkonkoma, N.Y."

"The ascent engine is a critical propulsion system on the Lunar Lander and its operation is required to return the astronauts from the lunar surface to rendezvous with the orbiting Crew Exploration Vehicle -- CEV," ATK said.

"A LOX/Methane propellant combination offers significant performance benefits over other propellant combinations. The engine is also significantly lighter weight and can provide increased safety margins for the Lunar Lander's design, in terms of allowable weight of the ascent module," the company said.

"Initial tests have already shown performance levels that meet or exceed engine requirements," said Bill Rutley, ATK senior program manager. "We took what we learned on the 7,500 lbf engine and incorporated design changes into the 3,500 lbf engine to improve its performance. Based on the latest test data, our vacuum specific impulse will surpass 350 seconds."