I just noticed how when the feather is deployed the shape of the vehicle as seen from the bottom looks like the STS shuttle wing shape.
...The problem is that despite public claims to the contrary, the nitrous oxide-rubber hybrid has never been hot fired on the ground at full duration, sources indicate. And the engine is not powerful enough even when fully fired to get SpaceShipTwo into space with any actual payloads (i.e., six wealthy passengers).
Even as Scaled Composites has pursued the flight test program and Virgin Galactic has issued optimistic flight predictions that commercial flights are only months away, the two companies have been secretly working on alternatives to the nitrous oxide-rubber engine they have been using to explore SpaceShipTwo’s flight envelope.
Sources report that the development of alternative hybrid designs has been running into trouble. An engine that used nitrous oxide and nylon exploded on Scaled Composites test stand on May 17. The nozzle and rocket casing were thrown clear and the test stand was wrecked. The composite tank holding the nitrous oxide did not explode, but it was damaged to the point where it could not be reused.
Scaled said they were testing an experimental, non-flight engine into which they had introduced flaws on that day. Sources say this is true; however, the explosion and wrecked test stand were not part of the test plan.
There has been work done on developing a liquid-fuel engine, which many experts see as a better long-term solution. A hybrid engine must be replaced after each flight, a process that is a delicate, complicated and expensive. A robust, reusable liquid engine would allow SpaceShipTwo to be refueled and fly again the same day.
It is not clear whether a liquid-fuel replacement is in active development at the moment, or how long it might take to get one ready for flight test on a SpaceShipTwo vehicle.
http://www.parabolicarc.com/2013/09/27/virgin-galactic-aiming-spaceflight-february/
I know Aerojet was offering a LOX/hydrocarbon engine of some sort for SS2. However, they opted for the hybrid for the time being because of simplicity.
As for an LH2 powered stage: :shifty: I'd prefer LOX/CH4, but there's none on the market. LOX/RP1 would probably be a good bet.
It would also necessitate a major redesign of the spacecraft.
Transitioning SpaceShipTwo to liquid fueled engines: a technology driver to reusable orbital launchers.
Exactly. Also, the post is another spam of him pointing to his own blog and no news or at least anywhere based on facts. His blog points to a rubbish book about Richard Branson, written by some guy who appears to be just another boulevard journalist. Thats where it all begins and ends.
http://www.parabolicarc.com/2014/01/22/scaled-updates-rm2-hot-fire-logs-boy-useless/
This is the only interesting thing there - but it means little. The lack of information can also be related to business secrets, remember, this is not the public NASA development.
That hybrid engines are pretty unknown for larger scales is no secret (do you know any example larger than RocketMotorOne?)... but the power density of a bipropellant rocket would be much lower and thus, have even LESS impulse available to reach suborbital flight for the given size of the spacecraft.
Any change in propulsion would mean a full redesign of everything. Including White Knight 2.
There is no evidence for any plans of a liquid fueled SS2. And I fail to see the link between SS2 and an orbital launcher.
Not just this author of the book on Branson but the author of that parabolicarc.com site have noted that the discussion at Mohave is that the original hybrid engine is underpowered to reach suborbital flight. The blog author Doug Messier is a respected reporter on space issues.
Any suborbital craft can serve as a lower stage to an orbital launch system. For instance XCOR is considering it for Lynx:
The problem is, that you have the criminal quoting habit to put words into the mouth of the people you quote, that have never said it in the source you link. As if you just read every third line, shout out in enthusiasm and post the link, saying "They are building reusable liquid engines, they are building SSTOs".
The fact that a different company plans to use liquid engine for a different craft designed for a different mission, is not evidence that Scaled are considering switching to liquid fuel.
Oh, but they DID consider it in the design phase: They approached Aerojet Sacramento about it briefly, then opted not to use liquids for simplicity and maintenance reasons.