Virgin Galactic incident

[Dr Jekyll]

An 'in flight anomaly' apparently. Worrying to say the least.

http://www.bbc.co.uk/news/world-us-canada-29857182

[Dr Jekyll]

Don't know, apparently 2 chutes spotted.

http://news.sky.com/story/1364455/virgin-galactic-...

[Dr Jekyll]

Rower said:

Very sad news indeed .

Listening to the radio this morning where the whole scheme was being discussed It was said that this engine was using different fuel as prior to this the fuel was 'rubber' . Can anyone explain how that works .....

HTPB, better described as synthetic rubber.
http://aeroconsystems.com/cart/motor-making-suppli...

Mix it with nitrous oxide and it burns rapidly, which is all rocket fuel needs to do. The HTPB is solid but the nitrous oxide is liquid and can be throttled giving the kind of control impossible with a pure solid fuel rocket.

The new fuel is plastic, similar to nylon I think, but still solid and used with nitrous oxide.

[Dr Jekyll]

dr_gn said:

Nothing to do with the propulsion system - apparently:

http://www.bbc.co.uk/news/world-us-canada-29876154

I don't get why deploying it at "Mach 1" would cause a disaster, yet if deployed at "Mach 1.4" it's normal.

Deployed at 1.4 isn't normal. The point is that they can unlock it at 1.4 without the danger of it deploying on it's own, at less than that the airflow can deploy it. It's unlocking it at Mach 1 that's the issue.