Virgin Galactic Statement on Upcoming Flight Test

SpaceShipTwo Unity during third flight test. (Credit: & Trumbull Studios)

MOJAVE, Calif. (Virgin Galactic PR) — Our SpaceShipTwo, VSS Unity, is entering the next stage of testing. During this phase of the flight program we will be expanding the envelope for altitude, air speed, loads, and thermal heating. We also plan to burn the rocket motor for durations which will see our pilots and spaceship reach space for the first time. Although this could happen as soon as Thursday morning, the nature of flight test means that it may take us a little longer to get to that milestone. It has taken years of design and manufacturing work by The Spaceship Company to get to this exciting stage and has required testing of all the parts and subsystems that make up SpaceShipTwo.
Only once we had completed all vehicle ground testing did we take Unity airborne; first mated to her carrier aircraft and mobile “wind tunnel” VMS Eve, then through a series of glide tests and finally to the three successful rocket powered supersonic flights we completed this year.

Incremental flight test programs are by definition open-ended and, to a great extent, each test depends on the data from the test that precedes it. There is no guarantee that everything will work perfectly first time and, like all programs seeking to take bold steps, we will inevitably have times when things don’t go as planned. Our team’s biggest priority is to use meticulous planning and preparation to ensure that stages are dealt with safely, and that every outcome informs and improves future performance.

In any human spaceflight program there is a high level of attention paid to crew safety—including not only what happens when everything is going as planned, but also when something unexpected occurs at any stage of flight. At Virgin Galactic, this approach is brought sharply into focus by the fact that SpaceShipTwo is crewed by two pilots. This means that circumstances may require the team to cancel or change plans either before take-off or in-flight in order to bring our pilots and the spaceship home safely. None of this though, takes away the excitement, anticipation and great pride of being at the vanguard of a new space age and of history in the making.


So, what are the plans for the next flight? Our window for our fourth powered test flight opens on December 13, 2018. We are currently planning to fly at the opening of that window on Thursday, pending acceptable weather and technical readiness. Overall the goal of this flight is to fly higher and faster than previous flights. We plan to burn the rocket motor for longer than we ever have in flight before, but not to its full duration. At the end stages of the rocket burn in the thin air of the mesosphere and with the speeds that we expect to achieve, additional altitude is added rapidly. That results in new and important data points, particularly relating to supersonic handling qualities and thermal dynamics, both of which we will be watching closely in the cockpit and on the ground in Mission Control. These observations will largely determine at what stage we decide to shut the rocket motor down. If all goes to plan our pilots will experience an extended period of micro-gravity as VSS Unity coasts to apogee, although – being pilots – they will remain securely strapped in throughout. They should also have some pretty spectacular views which we look forward to sharing as soon as possible post flight.

We are at a stage now in our testing program where we want to start simulating the commercial weight distribution in the spaceship represented by our future passengers. Excitingly, we are partly achieving that on the next flight by carrying four research payloads that are part of the NASA Flight Opportunities Program.

Whether we complete all our objectives during the next flight or need to wait a little longer, we remain committed to completing the final stages of this extraordinary flight test program as quickly, but more importantly as safely, as possible.

  • SamuelRoman13

    American manned spaceplane. Study
    2015. The Rocketplane XP Vehicle was a proposed suborbital manned
    spaceplane with accommodations for four crew.

    Status: Study 2015. Thrust: 160.00 kN (35,960 lbf). Gross mass: 8,840 kg (19,480 lb). Unfuelled mass: 4,340 kg (9,560 lb). Height: 13.00 m (42.00 ft). Diameter: 1.50 m (4.90 ft). Span: 7.50 m (24.60 ft).

    The vehicle would take off from a conventional airfield using turbojets,
    then use a rocket engine to accelerate to 1100 m/s, which would allow
    it to zoom to 100 kilometers and provide three to four minutes of

    The fighter-sized vehicle was fitted with a delta wing and
    a V-tail which provided good flight characteristics both subsonically
    and supersonically. The cabin environment was designed to maintain a
    comfortable temperature and pressure for the occupants while providing
    an excellent view of the Earth from space. It was constructed with many
    of the same systems as a conventional jet aircraft, but included
    features required for flight in space including a rocket engine,
    reaction control system (RCS), and internal air supply to provide a 0.7
    atmosphere cabin pressure.

    The thermal protection system, wing propellant tanks, and other systems
    were designed with the possibility of eventual upgrade to a longer-range

    In a typical mission, rocket ignition would take place between 6000 and
    9000 m altitude with the spaceplane in horizontal jet flight. A 3 to 4-G
    ascent profile would be flown, with engine cut-off at Mach 3.5 at
    45,000 m after 70 seconds of rocket powered flight. After up to four
    minutes of weightlessness, the passengers would pull 3 to 4 G’s on
    re-entry, followed by a glide to a landing at the departure airfield
    after a one-hour flight. After a three to five day turnaround, the
    rocketplane would be ready for another flight.

    Rocketplane XP subsystems included:

    Environmental Control and Life Support System using cryogenic liquid
    nitrogen and liquid oxygen and a chemical scrubbing agent to remove
    carbon dioxide.

    Two CJ610 business jet engines, derived from the military J-85, for takeoff and ascent to rocket ignition altitude.

    A Polaris Propulsion AR-36 160 kN liquid oxygen / kerosene
    regeneratively-cooled rocket engine with the injector based on the Atlas
    sustainer engine design. All composite tanks in the aft fuselage would
    be helium pressurized. A Barber Nichols turbopump, driven by hydrogen
    peroxide monopropellant, would deliver the propellants to the combustion

    A Space Vector reaction control system consisting of 12 cold nitrogen gas thrusters placed in opposing pairs.

    A Utah State University Flush Air Data System to determine
    pressure, airspeed, air density, alpha, and stall warning at all speeds,
    attitudes, and altitudes.

    An all electric, fly-by-wire flight control system with an
    elevon and aileron on each wing, and all-moving tail. Pilot inputs were
    processed by triple redundant flight control computers.
    Electromechanical actuators operating on 270VDC power drive the control

    An Electrical Power System mainly driven by a set of large lithium-ion batteries.

    An advanced fault tolerant BD Systems GN&C control and
    navigation system which takes inputs from the Flush Air Data System, a
    Global Positioning System (GPS), and an Inertial Navigation System.

    An ARINC, Data Acquisition and Integrated Vehicle Health Management System

    A thermal protection system to handle the 300 deg C re-entry
    heating, consisting of titanium leading edges and control services, and a
    special ceramic paint with a 93% emissivity on the rest of the

    Crew Size: 6. Crew: 430 kg (940 lb).
    Sounds safer and with better performance.

    Looks like a SRB attached to belly of Phantom Express. Using a expendable might up the cost per lb. They might as well stack the 2nd stage on the booster and get the same result. Which ATK did a long time ago.

  • ThomasLMatula

    I am praying that it goes well and they are not pushing it again.

  • Douglas Messier

    Amen to that! Last time around was a nightmare.

  • windbourne

    They did not push things at the accident. THe problem was pilot-error. Literally. Now, things are a great deal more automated .

  • redneck

    I would go with “induced pilot error”, but yeah.