SpaceShipThree to be Orbital Spacecraft

FleaPlus writes "The president of spaceflight company Virgin Galactic has recently stated that if the upcoming suborbital service with SpaceShipTwo is successful, the follow-up SpaceShipThree will be an orbital craft. Although orbital spaceflights would be much longer and could potentially dock with orbital space stations, they are also considerably more difficult than suborbital spaceflights. Other private firms working on orbital spaceflight (and potentially in the running for Robert Bigelow's $50 million America's Space Prize for orbital flight) include t/Space and SpaceX."

Comments

Re:PR bullshit

[dabigpaybackski]

IANARS, but I think Rutan ought to start thinking really big and start a privately-funded consortium to build a spaceport down in Ecuador. They build a launch ramp on the western slope of a mountain, as the Skyramp people are proposing, and rapidly put all of their competitors out of business.

Then, when the materials tech becomes practical, they build a space elevator on the very same site. Makes perfect sense; at that point, they have the name and a shitload of capital to make it happen. Taxpayers have spent enough on incremental baby steps and aerospace subsidies.

May dreams such as these take wing and I'd be happy just to watch: (link)

Re:Why SpaceShip[One|Two|Three] will not reach orb

[FleaPlus]

I'm under the impression that the direct speed/altitude benefits are fairly small. Rather, the main benefits are from safer abort methods (you can parachute back down if your engines fail) and being able to build an engine optimized for the upper atmosphere and space. You also don't have to pay launch site fees, and liability insurance becomes easier to deal with. Here's a relevant quote from t/Space's site:

http://www.transformspace.com/index.cfm?fuseaction =projects.view&workid=CCD3097A-96B6-175C-97F15F270 F2B83AA

The major benefits of air launch come in safety, simplicity and flexibility. Crew safety is enhanced because abort-at-ignition is easier when the capsule already is high enough for parachute deployment, vs. the on-the-pad challenge of releasing sufficient energy in the correct direction to send the capsule high enough for the parachutes to deploy. Public safety is enhanced because the launch takes place over open ocean, well away from any populated areas.

Air launch also allows simpler engines, which don't need to be designed to operate at both sea-level air pressure and at altitude. The "all-airborne" operation also reduces the performance penalty of using inexpensive low-pressure tanks and engines.

Flexibility and responsiveness is greatly enhanced by air launch. Most winds and precipitation at the airport runway -- launch site -- don't delay a launch; the carrier aircraft simply flies to clear weather. In addition, responsive launch often requires matching a particular inclination and orbit phasing. The carrier aircraft over open ocean can launch the CXV to any azimuth, and by flying across longitudes, can quickly match a desired orbit phasing.

The t/Space version of air launch provides only modest performance gains, in the 10-25% range, compared to a ground launch. It does not attempt technically difficult challenges such as accelerating the launch aircraft to supersonic speeds, or reaching very high altitudes.

Re:Only assuming thye use the same design

[Capt'n Hector]

The grandparent has a point though. A scalable SSTO (single stage to orbit) engine is a holy grail of sorts because it must provide lift in various situations while being near maximally efficient the whole time. Nasa (and everybody else) solved this by using multiple engines: liquid main engines, solid boosters for the shuttle). Now perhaps SC has found an engine that will get them to orbit, who knows, but it's a bigger problem than you might think. Fuel is an issue:

Fuels that are used in space must carry their own oxygen, but when going at high speeds in the earth's atmosphere, why not make like a jet engine and get oxygen from the atmosphere? Perhaps there could be two fuels, one for use in the atmosphere and one for use in space. The engine would start using one, then as pressure dropped would slowly switch to the other. But of course with an air intake that must work from zero to hypersonic speeds, you run into some pretty nasty physics in designing the thing. End result is you end up with a non-constant flow of oxygen to your engine, no matter how well you design your system. Thus the engine must be designed with this tolerance in mind.

So, anyone trying this: good luck!