Aerojet Rocketdyne has completed a series of hot-fire tests on two launch abort engines (LAE) that feature new propellant valves for Boeing's Crew Space Transportation (CST)-100 Starliner service module propulsion system.

Carried out in the Mojave Desert in California, US, the tests confirmed the ability for the new valves to modulate propellant flow and control peak LAE thrust in the event of a launch abort.

Designed by Aerojet Rocketdyne, the LAEs feature a fuel valve and oxidiser valve, which were developed and tested under the firm's Commercial Crew Transportation Capability (CCtCap) subcontract to Boeing.

"This is another important step forward as our nation prepares to safely and reliably send humans back to the space station from American soil."

Aerojet Rocketdyne CEO and president Eileen Drake said: "These innovative valves successfully enabled the engine to demonstrate precise timing, peak thrust control and steady-state thrust necessary during a mission abort. This testing culminates a year of dedicated hard work by the LAE integrated product team at Aerojet Rocketdyne.

"This is another important step forward as our nation prepares to safely and reliably send humans back to the space station from American soil."

According to the terms of the CCtCap subcontract to Boeing, Aerojet Rocketdyne will offer propulsion system hardware, which includes LAEs, orbital manoeuvring and attitude control (OMAC) thrusters, and reaction control system (RCS) thrusters.

Boeing will assemble propulsion hardware kits into the service module section of the Starliner spacecraft at its commercial crew and cargo processing facility at Nasa's Kennedy Space Center in Florida.

Aerojet Rocketdyne also offers hardware supporting service module hot-fire testing, which will take place at Nasa's White Sands Test Facility in New Mexico; the pad abort and system qualification testing, which will occur at White Sands Missile Range in New Mexico; and the orbital flight test, which will be launched from Cape Canaveral Air Force Station in Florida.

The Starliner service module propulsion system offers launch abort capability on the pad and during ascent, as well as propulsion needs during flight – from launch vehicle separation, docking to and undocking from the space station, to separation of the crew and service modules when the spacecraft begins to re-enter the Earth's atmosphere.

At separation, Aerojet Rocketdyne crew module monopropellant thrusters support re-entry control.

The Starliner service module and launch abort propulsion system is intended to quickly push a crew capsule to safety if an abort is required.

If unused for an abort, the propellant is used to complete the spacecraft's mission operations.

The Starliner service module propulsion system comes with four 40,000lb thrust launch abort engines used only in an abort; 1,500lb thrust class OMAC thrusters that offer low-altitude launch abort attitude control; manoeuvring and stage-separation functions, along with high-altitude direct abort capability and large orbital manoeuvres; and 100lb thrust class RCS engines that offer high-altitude abort attitude control, on-orbit low delta-v manoeuvring and space station re-boost capability.