SpaceShipTwo Back on the Ramp

mojave_tower_sunset_smBy Douglas Messier
Managing Editor

After a couple of months inside the hangar undergoing modifications, SpaceShipTwo is outside on the ramp today at the Mojave Air & Space Port in California.

Scaled Composites engineers are running the suborbital space plane through pressure tests on the cockpit, according to sources. The vehicle does not have an engine installed.

Virgin Galactic’s SpaceShipTwo last flew under power on Jan. 10, completing a 20-second burn of its hybrid nitrous oxide-rubber engine and reached an altitude of 71,000 feet. The ship flew again in an un-powered glide flight one week later before going into the hangar for changes.

Sources report that Sir Richard Branson’s space plane is undergoing a series of modifications to accommodate significant alterations in its propulsion system. The changes are designed to deal with oscillations and vibrations in the hybrid engine. Those oscillations are so severe that the engine cannot be fired to full duration without injuring the crew and damaging the ship.

It’s not clear when SpaceShipTwo will be flying under power again. Sources indicate powered flights might not resume until June or later. However, Scaled Composites and Virgin Galactic have been hoping to resume flights sooner than that.

After nearly 10 years of development, the goal is to fly SpaceShipTwo into space this year in a series of test flights. Scaled Composites, which is building and testing the craft, would then turn it over to Virgin Galactic.

The plan is for Branson to take the first flight near the end of the year with his two children, Sam and Holly. The flight will be broadcast live on NBC’s The Today Show.

Meanwhile, Scaled Composites has released hot fire summary logs for static hot fires conducted on the test stand in Mojave. As usual, the summaries are light on detail, indicating that an engine was fired and that all objectives were achieved. However, I can shed some light on one of them.

I saw hot fire no. 43 on Feb. 27. It appeared to be a firing of a nitrous oxide-nylon engine that Scaled is testing as an alternative to the nitrous oxide-rubber one that SpaceShipTwo has used for its three powered flights to date. I say that because it was very similar to a hot fire I saw in January that I know used nitrous oxide and nylon.

The Feb. 27 hot fire was clearly for SpaceShipTwo. I saw Virgin Galactic CEO George Whitesides and a number of subordinates watching the test from a frontage road off of Highway 14, not far from where I viewed the hot fire.

Sources say the alternative nitrous oxide-nylon engine is being tested because it could provide better performance. The modifications to SpaceShipTwo required for the revamped nitrous oxide-rubber engine will have an negative impact on the space vehicle’s performance.

RocketMotorTwo Hot-Fire Test Summaries
Via Scaled Composites

Fire:43
Date:27 Feb 14

Objectives:

Forty-third full scale flight design RM2 hot-fire. Continued evaluation of all systems and components:
– Pressurization
– Valve/Injector
– Fuel formulation and geometry
– Nozzle
– Structure
– Performance

Results:

All objectives completed.


Fire:42
Date:20 Jan 14

Objectives:

Forty-second full scale flight design RM2 hot-fire. Continued evaluation of all systems and components:
– Pressurization
– Valve/Injector
– Fuel formulation and geometry
– Nozzle
– Structure
– Performance

Results:

All objectives completed.