Engineers Continue Ground Tests on SpaceShipTwo’s Engine(s)

Nitrous nylon engine test on Jan. 16, 2014. (Credit: Ken Brown)
Nitrous nylon engine test on Jan. 16, 2014. (Credit: Ken Brown)

With Virgin Galactic Founder Richard Branson once again supremely confident (90 percent probability!) that he will be flying to space by a definitive date (end of September!), you would think that all the ground testing of SpaceShipTwo’s engine would have been completed long ago.

But, you’d be wrong. As usual. Engineers have been testing up a storm lately, with static engine firings every couple of weeks. And with SpaceShipTwo having not flown for nearly four months, you’d be right to wonder why Sir Richard’s predictions are always so at odds with any known reality in Mojave.

Once again, I managed to witness one of these tests quite by accident. I was driving into Mojave on Highway 14 on Thursday afternoon, and suddenly these giant flames shoots up from the ground off in the test area. For most people, that would be rather shocking, once in a lifetime event. But around Mojave, that’s just what we call Thursday.

The flames looked a lot like the picture shown above, which is from the test of a hybrid nylon-nitrous oxide engine in January. I believe this test was of the same engine design. The engine fired for close to a minute, and it looked pretty good, although I admittedly don’t know all that much about such things. The flames were clear and the combustion seemed stable, at least until just before shutdown when it seemed to burp. That’s not a technical term, but the flame sort of went down and then went up briefly before shutting down. That was followed by venting of some white gas, which was probably the nitrous oxide.

Others who do know about these things told me it looked pretty good to them. They also told me that it sounded good. Experienced rocket engineers develop an ear for such things; they can hear anomalies in an engine when it’s fired. They know it when they hear it. This is akin to starting up your car and hearing the engine run roughly.

This was the second time I’d been driving down the 14 at a random time and happened to witness a SpaceShipTwo hot fire. On the previous occasion, I noticed a gaggle of Virgin Galacticans led by CEO George Whitesides standing on the frontage road, peering intently toward the test stand. That was a pretty good that something was about to happen. I managed to pull off the highway and park in time to see the engine test.

This time, there was no on the frontage road watching this test. Whether they were viewing it from some other, less conspicuous location, I cannot say. If they weren’t, they missed a pretty big show.

Below are the latest updates to Scaled’s hot fire test summaries page. As usual, the entries provide no information about which engines have been tested (nitrous-nylon or nitrous-rubber), how long they were fired, or other information that would give anyone outside the company any clue as how the testing is progressing. And, of course, all objectives were achieved.

RocketMotorTwo Hot-Fire Test Summaries

Fire:48
Date:07 May 14

Objectives:
Forty-eighth 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:47
Date:17 Apr 14

Objectives:
Forty-seventh 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:46
Date:17 Apr 14

Objectives:
Forty-sixth 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:45
Date:09 Apr 14

Objectives:
Forty-fifth 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.