Virgin Galactic Set to Attempt Spaceflight on Thursday

View of SpaceShipTwo Unity from the tail boom. (Credit: Virgin Galactic)

Virgin Galactic announced today that it would attempt the fourth flight of SpaceShipTwo Unity as early as Thursday morning from the Mojave Air and Space Port. The launch window runs through Saturday, Dec. 15.

“We plan to burn the rocket motor for longer than we ever have in flight before, but not to its full duration,” the company said in a statement that indicated the vehicle could reach a “space altitude.”

A full duration burn of Unity’s hybrid rubber-nitrous oxide engine would take approximately 60 seconds. This week’s flight will likely include a pilot and co-pilot but no passengers.

During its most recent flight test on July 26, Unity fired its hybrid engine for 42 seconds and reached an altitude of 32.3 miles (170,800 ft/52 km). It was the longest engine burn and highest flight in the program’s 14-year history.

By space altitude, Richard Branson’s space company apparently means the 50-mile (264,000 ft/80.4 km) boundary set by the U.S. Air Force for awarding astronaut wings to X-15 pilots in the 1960’s.

The Fédération Aéronautique Internationale (FAI), which is the world governing body for air sports, sets the boundary of space at 100 km (62.1 miles/328,084 ft) . FAI recently announced it was exploring whether to lower the boundary to 80 km.

The 4.5-month long gap in powered flights is the longest for Virgin Galactic’s second SpaceShipTwo. The previous three tests came at roughly 2-month intervals.

Sources in Mojave say engineers have been grappling with several issues since July. The most serious one is a crack that was discovered in one of SpaceShipTwo’s major structural components. It’s not clear how the problem was addressed.

  • The Other Dr. Phil

    I saw the NOTAM earlier this morning (keeping my eyes out for something else) and it only goes to 17,999 feet MSL… ?

  • Kenneth_Brown

    That is really strange on the altitude. I don’t find anything on the sectional chart that would make 18k’ make sense.

  • ThomasLMatula

    Isn’t 18K the start of controlled air space? If so then it makes sense to limit it to 17,999 ft since ATC would be in charge about that altitude.

  • The Other Dr. Phil

    Blue Origin’s past NOTAMS (only thing I have on hand for reference) are “From the surface up to Unlimited”

  • Kenneth_Brown

    No, controlled airspace varies by location. Class A airspace begins at 18,000′ MSL which is where jets normally operate. The whole of the area around the Mojave airport is covered with MOA’s (Military Operating Areas). R-2515 is the airspace surrounding Edwards AFB and is restricted from the surface on up to the top of the atmosphere as near as I can make out. SS2/WK2 also fly in the Isabella MOA which is 1,500′-3,000′ and up.

    Just the captive portion of the flight spends a lot of time in Class A airspace. SS2 is going to go way above that. I’m guessing that ATC is going to be routing all flights around the NOTAM area. Since IFR flights are filed and approved in advance and also require constant radio communication with controllers, it’s not hard to keep the area clear. That there is a lot of military stuff going on makes it even easier since not much goes overhead to start with.