Suborbital Spotlight: Virgin Galactic’s SpaceShipTwo

Gear down on SpaceShipTwo. (Photo: Mark Greenberg)

NASA’s Office of Chief Technologist has published detailed information about suborbital vehicles that will be available beginning in 2011 for researchers to conduct microgravity experiments. The vehicles are being built by Armadillo Aerospace, Blue Origin, Masten Space Systems, Virgin Galactic, and XCOR.

Today we will look at Virgin Galactic’s SpaceShipTwo.  The eight-seat suborbital vehicle built by Scaled Composites is currently being tested in Mojave, Calif.

PLATFORM

SpaceShipTwo (SS2) uses all the same basic technology, carbon composite construction and design as SpaceShipOne (SS1). However it is around twice as large as that vehicle and will carry six passengers and two pilots. It is 18.3 m (60 ft) long with a 2.28 m (90″) diameter cabin which is similar in size to a Falcon 900 executive jet albeit with no floor dissecting the cabin allowing maximum room for the astronauts to float in zero gravity.

FLIGHT PROFILE

SpaceShipTwo is carried to its launch altitude of approximately 15 km (approx. 45,000 ft) by the purpose-built carrier aircraft WhiteKnightTwo (WK2). This climb up to altitude takes around an hour. SpaceShipTwo is subsequently air-launched from the carrier and fires its rocket motor, executing a turn for a steep climb which lasts ~70 seconds before the motor shuts down.

A nominal SS2 payload (including passengers and crew) is expected to result in an apogee of 110 km (360,000 ft) using the flight profile described above. VG expects to fly the described nominal mission profile with high accuracy and repeatability.

SpaceShipTwo then follows a typical ballistic arc and deploys its ‘feathered’ configuration for re-entry. Following ~70 seconds of re-entry and descent into the atmosphere, SS2 de-feathers and glides to a horizontal landing at its launch base.

Passengers and payload will experience up to 4 G on launch and a peak of 6 G on re-entry. Launch g’s reach a maximum of 4 g.’s in both gx and gz vectors during boost, though gz vectors are of short duration during the pull up maneuver only. Any passengers are seated during boost, taking the boost g forces through the chest for the long duration component. Re-entry G’s are taken in a supine position for passengers, directing the g through the chest (gx axis relative to the passenger), which is more tolerable.

There are two opportunities to do atmospheric science, on ascent and descent of approximately 20 seconds each, and one opportunity of approximately 4 minutes to undertake microgravity science.

Accuracy and repeatability, as well as safety are critical operational characteristics for the VG tourism and science markets. However, VG also anticipates the ability to be able to accurately target a specific altitude and hence microgravity times, within the design range of the spaceflight system, on demand. This design range (to be confirmed during flight testing) is between 70 – 130km.

PAYLOAD CONFIGURATION

SpaceShipTwo will have a baseline seat for tourism operations and baseline rack for individual (direct passenger replacement) payloads. VG will be able to offer researchers several services:

  • Researchers will be able to tend and optimize their experiments in space by mounting them inside the SS2 flight cabin. SS2’s large volume, substantial payload capacity, and multiple windows make the cabin well suited to a wide variety of research applications.
  • Alternatively researchers will be able to request the management of experiments by VG staff or provide autonomous experiment set ups.
  • Researchers will be able to mount experiments in the interior, pressurized cabin of the SS2 and/or in unpressurized bays of the SS2 for research requiring direct access to the space environment. Such experiments can for example, take atmospheric samples and allow exposure to the external spaceflight environment.
  • WK2 will offer an excellent proving and training environment for SS2’s cabin, as well as an excellent high altitude research platform in itself. By design, WK2’s cabin is virtually identical to that of SS2, and WK2 is capable of flying zero G parabolas.

VG will have a baseline seat for tourism operations and baseline rack for individual (direct passenger replacement) payloads. Details of the payload rack will be provided when available, however VG is willing to work with NASA and/or other payload customers to accommodate different types of payloads and racks.

POTENTIAL FLIGHT RATES

SS2 is being designed to fly twice daily. WK2 is being designed to support four spaceflights daily. VG aims to fly 500 passengers in the first year of commercial operations and an estimated 30,000 passengers over 10 years.

During initial commercial operations, VG is targeting a conservative flight rate of once per week rising to 3 times per week towards the end of year 1. Within two years VG expects to be flying daily and is planning to have the operational capacity to turn around multiple flights per day within three years from the start of commercial operations. Virgin Galactic hopes to eventually be able to support back to back flights with a three-hour turnaround.

LAUNCH/LANDING SITES

Commercial operations are baselined for New Mexico’s Spaceport America, being constructed adjacent to the White Sands Missile Range. Test flights of the system are expected to be performed at the Mojave Air and Space Port.

Terminal Hangar Facility at Spaceport America.

With proper spaceport and commercial licensing, the SS2/WK2 spaceflight system will be capable of operating from any typical airfield with a runway of more than 9,000 ft. Specialist equipment is limited allowing operations from alternate locations with relative ease. The WK2 will be capable of ferrying an empty SS2 over 2000 nautical miles allowing access to a wide range of potential launch locations in the US.

Editor’s Note: The above information was compiled from NASA’s Flight Opportunities Program website and Virgin Galactic’s public Request for Information (RFI) response for the CRuSR program. A shout out to Clark Lindsey of Hobby Space for originally finding the published information.