Spaceship Two, affectionately christened VSS Enterprise, completed its third test flight last Thursday at the Mojave Air and Space Port in California. Under development by Scaled Composites, LLC, Enterprise is a prototype sub orbital rocket plane currently undergoing an incremental flight test program which will culminate in its certification for use as a passenger carrying spacecraft to be operated by Virgin Galactic Spacelines. Thursday’s 6 hour and 12 minute long mission was the third “captive carry” test flight during which Enterprise remained attached to the Whiteknight Two (WK2) mother ship. WK2, with its unique twin fuselage booms, is a light weight high altitude carrier aircraft developed by Scaled to serve as the launch platform for Spaceship Two. Because it has controls and systems that are nearly identical to those used by Enterprise, WK2 serves as both a test bed for systems development and a flight training device for pilots that will ultimately fly the spaceship. Unlike the previous two test flights conducted on March 22 and May 16, this was the first time that Enterprise flew with a crew on board. During the first two captive flight tests only three crew members, a pilot, copilot and flight engineer flew aboard the WK2 mother ship. For CC-03 (captive carry flight #3), test pilots Peter Siebold and Michael Alsbury were at the controls of Enterprise, and Mark Stucky, Peter Kalogiannis and Brian Maisler were aboard Whiteknight Two. The team conducted additional testing of the spaceship’s systems, evaluations of mated flutter characteristics, and a rehearsal of the procedures to be used during the upcoming “glide flights” from the point of release down to a low approach above the Mojave airport runway. Prior to taking to the air for the mated flight test, Enterprise was subjected to 3 hours of taxi tests last Monday. The ground tests allowed the team to evaluate the performance of the landing gear, brake, steering and skid shoe systems at speeds ranging from 25 to 60 mph.
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| Whiteknight Two carries VSS Enterprise aloft between the its dual fuselage booms for the third captive carry flight (CC-03) as a chase aircraft monitors the test. Photo courtesy: Virgin Galactic |
So far both Scaled Composites and Virgin Galactic have been tight lipped about the details and timing of their flight test program but many observers are predicting that the first solo glide flight of Enterprise will take place early this fall. For the glide flights, Enterprise will be carried to a launch altitude of ~45,000 to 50,000 feet where it will be released and flown to an unpowered runway landing. As the spaceship’s handling qualities and flight characteristics are evaluated and quantified, the flight test program will progress into the powered flight phase. During powered flight testing, Enterprise will fire its hybrid rocket motor – consisting of Nitrous Oxide as an oxidizer and a rubber compound as the fuel - after being dropped from WK2 at launch altitude. As the powered flights progress, Enterprise will achieve ever increasing speeds and altitudes in an effort to incrementally expand its flight envelope and ultimately certify it for sub-orbital space flight. Measuring 60 feet in length with a wingspan of 27 feet, Spaceship Two is described by Virgin Galactic as being about the size of a Falcon 900 business jet. It contains a unique and spacious 12 foot long, 7.5 foot wide, cabin covered by numerous large diameter windows. With two pilots at the controls, Virgin hopes to take 6 fair paying passengers on the ride of their life. Peaking out altitudes of up to 360,000 feet and velocities of around mach 3 (3 time the speed of sound), the passengers will be allowed to unstrap from their seats and experience a brief period of weightlessness (free fall) as the craft follows a ballistic trajectory above the majority of the earth’s atmosphere. The passengers will then return to their seats for the relatively high G forces of re-entry and the steep gliding flight back to the runway.
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