SpaceShipTwo Unity Completes First Powered Flight

VSS Unity lands back at the Mojave Air and Space Port after its first powered flight. (Credit: Virgin Galactic)

MOJAVE, Calif. (Virgin Galactic PR) — We are delighted to report on a major step forward for Virgin Galactic today, as SpaceShipTwo VSS Unity safely and successfully completed her first supersonic, rocket-powered flight. After two years of extensive ground and atmospheric testing, the passing of this milestone marks the start of the final portion of Unity’s flight test program.

The flight was also significant for Virgin Galactic’s Mojave based, sister manufacturing organization, The Spaceship Company. Unity is the first vehicle to be built from scratch for Virgin Galactic by The Spaceship Company’s talented team of aerospace engineers and technicians. They were justifiably proud today to be a part of this compelling demonstration of their capabilities in action.

VSS Unity benefits from all the data and lessons gathered from the test program of her predecessor vehicle, VSS Enterprise. Today’s flight saw an envelope expansion for the program as a whole in terms of rocket burn duration, speed and altitude achieved.

VSS Unity took off this morning into clear Mojave skies at 8:02am with Mark “Forger” Stucky and Dave Mackay in the cockpit, attached to the WhiteKnightTwo carrier aircraft, VMS Eve, piloted today by Mike Masucci and Nicola Pecile.

The mated vehicles climbed to a launch altitude of around 46,500ft over the Sierra Nevada Mountains and while pointing back at Mojave, Eve executed a clean release of Unity. After a few seconds, Unity’s rocket motor was brought to life and the pilots aimed the spaceship upwards into an 80 degree climb, accelerating to Mach 1.87 during the 30 seconds of rocket burn. The hybrid (nitrous oxide / HTPB compound) rocket motor, which was designed, built and tested by The Spaceship Company, powered Unity today through the transonic range and into supersonic flight for the first time.

On rocket shutdown, Unity continued an upwards coast to an apogee of 84,271 feet before readying for the downhill return. At this stage, the pilots raised the vehicle’s tail booms to a 60 degree angle to the fuselage, into the ‘feathered’ configuration. This unique design feature, which is key to a reliable and repeatable re-entry capability for a winged vehicle, incorporates the additional safety mechanisms adopted after the 2014 VSS Enterprise test flight accident.

At around 50,000ft,   the tail-booms were lowered again and, while jettisoning the remaining oxidizer, Unity turned towards Mojave for the glide home and a smooth runway landing.

The flight has generated valuable data on flight, motor and vehicle performance which our engineers will be reviewing. It also marks a key moment for the test flight program, entering now the exciting phase of powered flight and the expansion to full duration rocket burns. While we celebrate that achievement, the team remains focused on the challenging tasks which still lie ahead.

Congratulations to our teams at Virgin Galactic and The Spaceship Company for a job well done today – and in recognition of their pursuit to open space and change the world for good.

Please stay tuned to this site and our social media channels (Twitter, Facebook and LinkedIn) for more information as our flight testing program progresses.

  • Hemingway

    Karman line for outer space is an altitude of 62 miles or 330,000 feet. Will SpaceShipTwo reach true outer space is the question.

  • Congratulations to everyone at Virgin Galactic and TheSpaceShipCompany for a safe and successful flight! I was watching every report with hope and prayers for Forger’s and Dave’s successful touch down.

    A lot of hard work, technical, marketing, and financing, went into this success, but, even more importantly, it is wonderful to see the investment of work life, risk to life, and sacrifice bear some fruit. My hopes are for that multiplicity of dedication to be the key that expands the vehicle’s operational envelop and realizes the Virgin Galactic dream.

    I am thankful for their good day. : )

  • windbourne

    Hey, they are finally back to flying.
    Hopefully they have addressed all the old issues, esp the lack of thrust before, and will be successful now.

    If they, or BO, can start flying passengers, it will further the space interest that is going on.

    Ideally, VG and BO can use these for initial training of future astronauts, esp for other nations. Combine with Bigelow and then SpaceX BFR, and we can do the moon in 4 years.

  • Lee

    Are you an investor? Or just a cheerleader? This thing is one giant accident just waiting to happen.

  • JS Initials

    Even though this flight topped off at a little over 25 km (80-82,000 ft+), the crew experienced a longer interval of zero-g than you can PAY for on a “Parabolic Arc aircraft flight” (Mr Messier probably likes that reference). Also…when was the last time, Mr Hemingway, that you saw a charcoal black sky with your own eyes? When was the last time you saw the curvature of the Earth with your own eyes? …When was the last time you saw the horizon some 350 miles away with your own eyes?…Not yet?…Well….even the defunct Lynx rocket-plane project never promised space for paying passengers, but I’m sure those who would have been passengers on the Lynx would have loved to have seen those things and experienced those things, even if some arbitrary line was not reached.

  • Hemingway

    All for $200,000 – wow

  • JS Initials

    The defunct Lynx project? What were they asking passengers to pay?

  • Hemingway

    $150,000!

  • ThomasLMatula

    Congratulations! It is good to see them moving forward.

  • Philip Heruterus

    Wow! You sure changed your tune from several years ago after you quit VG… Why all the sucking up now?

  • I am a former VG employee with an unvarnished (but NDA restricted) understanding of the Virgin Galactic internal challenges (and successes) over my 2011 to 2014 tenure there. I understand the various approach contrasts, having also worked at SpaceX, Firefly, and NASA. My 2009 career transition from petrochemical and finance industry software to space software has been a highlight of my professional life. I confess to being an optimistic ‘New Space Fanboi’ who can often be found effusing over the latest SpaceX achievement.

    That said, regardless of your (or my) opinion of VG’s business case or of their ((risk)(cost)(time)) : (technical achievement) ratio, there are a lot of hardworking people at VG who are trying not just to achieve Richard Branson’s dreams, but their own. It is difficult to find someone willing and able to fund new space dreams, and we can’t all work for SpaceX.

    While not close friends, I’ve worked with both pilots on today’s flights, particularly Dave, and I respect them as people who fully understand the risks and take those risks anyway in order to try and achieve something. My thoughts were with them on their flight today.

    I am continually amazed at VGs steadfast ability to fund their work at the level they do. I would love to see them be successful.

    Check my limited and constrained comment history here, if you like. ‘Cheerleader’ would likely be an overstatement.

    I have no financial interest in VG, but a few friends and many ‘work acquaintances’ are still there…

  • There are a “whole lot” of ridiculously wealthy people (not me!) that casually spend more than $250,000 a quarter per family member on vacations. When I worked in financial software, the company I worked for had a whole international bank set up just for them and each depositor had their own dedicated full time concierge team set up to arrange their fun. For those people risk is an issue, but, otherwise, the cost is minimal for a chance to one-up their friends’ adventure story at the next party.

  • Not sucking up. Just glad for a successful flight. Any successful flight.

    My technical and business opinions about VG haven’t changed, though they aren’t freely available in substantiated form to the public due to the perpetual NDA. I perceive you may have had access to confidential internal documentation of those opinions… : )

    Based on my pre-New Space career in the private sector and my phenomenal experience at SpaceX, I didn’t, then, viscerally understand the extent to which our cold war birthed aerospace industry chews up vast legions of engineering career lifetimes on projects that deliver little or nothing. In that context, VG’s persistence that has enabled their return to powered flight today ranks somewhat higher in my estimation than in might have in 2014.

    Regardless, they built something that worked today, nobody died, and I think that is worthy of a good word, even from their constrained critics.

  • JS Initials

    Mr Roberson? IYHO, will Virgin Galactic now become more open about the engineering issues and flight scheduling of their SS2 rocket-plane? It seems to me that VG was more tight-lipped and secretive about the engineering issues and planned flight scheduling than those folks working at Area 51 these past five years….One engineering issue that kept repeatedly coming up in forums was and is, will the SS2 Unity be able to achieve and surpass the 100 kilometer mark with six passengers onboard? Also…is the SS2 Unity using nylon or latex rubber for fuel?

  • Bob Redman

    Why is there so much hate and venom on this thread? Knock it off. I’ve been a casual observer of the program over the years and applaud TheSpaceShipCompany’s achievement in powered flight on the new bird. I only wish them the best as they go forward. Stop looking backward and hope their success continues.

  • redneck

    Looking backwards is often a clue to activity forward, and this company has earned some sceptisizm Or, those that don’t study history may watch it repeat.

  • Lee

    You applaud them for taking 14 years to go from scratch to not putting anyone above the Karman line, let alone carrying passengers there? Oh yeah, and for killing a few people along the way. In about the same amount of time, with far less money, SpaceX has gone from scratch to the most powerful booster on the planet currently in use. I also don’t think they’ve killed anyone yet, although to be fair, they haven’t launched anyone yet either. But VG managed to kill a couple of people on the ground during a motor test.

    I’m sure the people working for Branson mean well, and I’m sure they’re not looking to hurt or kill anyone. However, they are handicapped by the vehicle they are trying to make work for this purpose. If you tried, you couldn’t come up with a vehicle more wrong for the task at hand.

    I’m sure a lot of the vitriol here stems from the fact that many of us have been a part of hair-brained projects thought up by people like Branson who apparently don’t understand physics, to say nothing of mechanical engineering and kinematics. Luckily none of the couple of these I’ve been involved in have cost any lives, but they did cost millions of dollars, for no real return, all because the “money man” was trying to do things that were physically impossible. So we’ve been there and done that, and recognize the type.

    By what background do you judge the progress of VG?

  • I don’t know. My intimate knowledge of VG is out of date. I presume they have continued to improve their business, process, and technology at a pace that is acceptable to their investors. It is a very big step to go from buying a rocket plane from Scaled Composites to building one yourself based on that design…

    I think VG will remain tight-lipped about details of their technology forever. I think they are very savvy about who their audience is (the general public’s positive recognition of the Virgin brand and non-engineering members of affluent society) and their strategy toward corporate intellectual property (hyper-protective). I suggest you look to their concrete, demonstrated, and public accomplishments (like Unity’s first powered flight) for progress and don’t expect to ever learn exactly how they did it.

    I think the VG business plan has a similar chance of success whether or not they pass the 100 K mark and whether or not they carry six or fewer passengers. In a project like this, we engineers tend to undervalue the benefits investors perceive from prestige, PR, spinoff business, and association. I think their first few years of customer rides only have to provide an “awesome”, presumed safe, and enthusiastically talked about “space experience” for their investors and ticket holders to stay engaged. I don’t think they even have to come close to making an on-the-books profit.

    I don’t know for sure what fuel they are using today – the plume looks pretty much the same as earlier powered flights, don’t you think? … However, if I were building a sub-orbital rocket plane from scratch, I would build it with electric pump driven RP-1 / LOX or Methane / LOX liquid propulsion, depending on my system design business targets (Faster to market with less reuse: RP-1; Slower to market with more reuse and faster turnaround: Methane).

  • Nathan Lewis

    Since you used to work for VG I hope you don’t mind if I ask a purely technical question. What is the benefit or the perceived benefit of a hybrid rocket engine? I’m not an aerospace engineer just a lay person interested in this stuff. If one of the fuels is liquid why not make both liquid? The liquid will have to be pumped and you can’t use fuel to power the pumps because one is solid so it seems you are forced to use the electron approach. Is the benefit that you only need half the battery power that the electron requires?

  • OldCodger

    You’r not their market demographic!

  • Douglas Messier

    Presumed safe?

    I dunno. Just to fly their shrinking manifest of around 650 passengers (down from over 700) that would mean more than 100 flights. Statistically, there’s a high probability of at least one catastrophic failure that scatters a half dozen high net worth individuals and two pilots all over the desert.

    Then what happens to all that prestige? Branson blamed the press, Alsbury and Scaled (in that order) for the two previous accidents that took four lives. Now, he’s got no one to blame but himself if anything goes wrong.

  • I think their investors and customers would be ‘OK’ with ‘presumed safe + no customer accidents (lucky) + no profits’ … and that then they would springboard to their next thing.

    By the way: I was surprised when working on another project (not VG) where I found the ‘official view’ and ‘team training’ definition of ‘risk’ was “The stakeholder’s perception of the probability of failure” rather than the “actual (and perhaps unknown) probability of failure.” Under that definition, concealing the actual probability of failure from the stakeholders and convincing them of a lower probability of failure was officially tagged as “risk reduction.” ‘Just one of the jaw dropping ‘noob in big aerospace’ moments I’ve experienced….

  • Hybrid:
    ‘Hybrid’, in this case, means solid fuel and liquid oxidizer. Published reports state that VG uses HTPB (~ the same stuff as automotive tires) for the solid fuel and NitrousOxide for the oxidizer.
    (1) The primary safety benefit of this sort of hybrid is in its comparison to a solid rocket booster (SRB= both fuel and oxidizer premixed in the fuel grain). A fueled hybrid engine like this is separate from the oxidizer and is not particularly hazardous. You can make it in a fairly standard industrial fixture and transport it safely by normal freight. In contrast, an SRB is a hazardous explosive that requires much more specialized equipment, crews, permits, handling, and transport.
    (2) Another safety benefit, over an SRB, is that by closing a valve to shut off the oxidizer you can turn the hybrid rocket off in mid-boost (where an SRB just burns until it is used up and can’t be turned off).
    (3) A theoretical safety benefit of a hybrid over a liquid rocket engine is that is might be simpler (fewer pumps, valves, plumbing, etc…) thus having fewer failure modes, but this is difficult to actually realize in a large scaled stable thrust hybrid.

    Operational challenges of hybrid compared to liquid rocket engines include: thrust instability at larger scale (shakes the spacecraft too much) and less predictable overall thrust (you aren’t as sure you will go as high/fast as you would like), among other things…

    Liquid:
    (1) Why not use a fully liquid rocket engine? For reusable human flight I think one of the several possible liquid rocket solutions is the best choice (e.g.: Blue Origin). I can’t really comment on details of why VG didn’t use a liquid rocket except to say that I don’t think their reasons are particularly technical other than that they started with the successful, but smaller, SpaceShipOne design.
    (2) Pumping liquid fuel and oxidizer? The simplest way to pump liquids on a rocket is to build your tanks to be able to handle engine chamber pressure, carry a highly pressurized inert gas (e.g. He) in a separate tank, and then use the inert gas to push the Fuel/Oxidizer liquids from their tanks and into the engine. This makes the tanks heavy and the pressurization system heavy, but it is pretty simple mechanically. A higher overall performance design would use lower pressure (lighter) tanks and a pump system that pumps the liquids up to engine chamber pressure. Pumps can be powered several different ways: gas generator, battery-electric, staged combustion, tapoff… Each with their own tradeoffs. Mechanical pumps are complex so they offer more failure modes that must be considered in the design.

    NitrousOxide
    Incidentally, it is very dangerous to mechanically pump high pressure NitrousOxide (because it can spontaneously decompose), so such systems are ‘pumped’ using the first method of simply pressurizing the tanks with an inert gas to push the liquid out. (Some solutions might use of NitrousOxide’s self pressurization properties, but this is not particularly high performance.) Handling NitrousOxide at high pressure, particularly at warm temperatures, can be highly hazardous and would be a key concern for any rocket (hybrid or liquid) that uses high pressure NitrousOxide. Ways to mitigate this hazard (other than to lower the pressure, temperature, or both) and their demonstrated effectiveness are not well understood in the public literature.

  • (Rewritten repost, prior post appears to have been lost somehow)
    Hybrid:
    In this case “hybrid” means solid fuel, liquid oxidizer. VG is publicly reported to use HTPB (synthetic rubber like in roller coaster tires) for fuel and NitrousOxide for oxidizer.
    Hybrid benefits include:
    (1) Safer, compared to a Solid Rocket Booster (SRB), to manufacture, store, and transport. A fueled hybrid rocket can be manufactured, handled, and transported in a manner similar to automotive tires, where an SRB is a hazardous explosive that requires special training, equipment, and permits.
    (2) Safer, compared to an SRB, because it can be turned off after ignition by shutting off the oxidizer where and SRB must burn until it burns out.
    (3) Safer for the environment, compared to an SRB, because it puts out fewer toxic chemicals than a typical SRB.
    (4) Theoretically, compared to liquid rockets, requires only half the plumbing and pumping (this benefit may be difficult to realize for a large scale stable thrust hybrid rocket).
    Hybrid disadvantages include:
    (1) Compared to liquid fueled rockets, less stable thrust at larger scales (may shake the spacecraft too much).
    (2) Compared to liquid fueled rockets, less predictable total thrust over burn (may not achieved target delta-V).

    NitrousOxide:
    (1) Can’t be mechanically pumped at high pressures (e.g.: 800 PSI) because this is likely to cause rapid decomposition (causing an effect rather like an “explosion”).
    (2) Difficult to handle safely at high pressures, and there isn’t good public literature on how to mitigate this hazard.
    (3) (Benefit) For low performance applications, NitrousOxide can self pressurize.
    (4) (Benefit) At low pressure, NitrousOxide is relatively safe.

    Liquid rockets:
    If I were making a suborbital rocket plane from scratch, I would use a liquid rocket engine, either RP-1/LOX or Methane/LOX.
    Liquids, whether both fuel and oxidizer (liquid engine) or just oxidizer (hybrid), must be delivered to the rocket engine at slightly above operating rocket chamber pressure. There are two basic ways to achieve this:
    (1) Use higher pressure tanks than can handle the engine chamber pressure (this makes the tanks heavy). Use another very high pressure tank to hold a very high pressure inert gas (e.g.: He). Use the very high pressure He through a regulator to displace the liquids in the high pressure tanks as they are used up by the engine.
    (2) Use lower pressure (lighter) tanks with mechanical pumps to pump the liquids up to engine pressure. A number of different power sources for the pumps might be used: gas generator, staged combustion, battery electric, tapoff, piston… Inert gas pressurizing is still required to displace the liquid, but it isn’t nearly as much since it is lower pressure. Disadvantage: Complex mechanical pumps have more failure modes. Advantage: Mechanical pumps are the only practical solution for the highest engine chamber pressures (higher performing engines).

    Why did VG choose a hybrid rocket motor?
    I think it is mainly because the successful SpaceShipOne used a hybrid rocket motor (though it was much smaller) and that VG felt it was good PR to stay with that design despite the engineering challenges of scaling the engine up for SpaceShipTwo. Why did Burt Rutan pick a hybrid for SpaceShipOne? There is a public story about him watching a video of a liquid engine exploding and another one of a hybrid engine performing as planned – that plus the theoretical simplicity of the hybrid may be what inspired him to make the selection.
    Why did they pick NitrousOxide for the oxidizer? I think it may have been presumed safe based on its ubiquitous low pressure use, but the reality turned out to be more complicated than initially thought.

  • Sorry Nathan…. I’ve tried to post this two times before, but it doesn’t ever show up… I’m not looking for an audience, just wanted to respond to you personally… So, I’ll try to post it directly to the Disqus website:

    (Rewritten repost, prior post appears to have been lost somehow)

    Hybrid:

    In this case “hybrid” means solid fuel, liquid oxidizer. VG is publicly reported to use HTPB (synthetic rubber like in roller coaster tires) for fuel and NitrousOxide for oxidizer.

    Hybrid benefits include:

    (1) Safer, compared to a Solid Rocket Booster (SRB), to manufacture, store, and transport. A fueled hybrid rocket can be manufactured, handled, and transported in a manner similar to automotive tires, where an SRB is a hazardous explosive that requires special training, equipment, and permits.

    (2) Safer, compared to an SRB, because it can be turned off after ignition by shutting off the oxidizer where and SRB must burn until it burns out.

    (3) Safer for the environment, compared to an SRB, because it puts out fewer toxic chemicals than a typical SRB.

    (4) Theoretically, compared to liquid rockets, requires only half the plumbing and pumping (this benefit may be difficult to realize for a large scale stable thrust hybrid rocket).

    Hybrid disadvantages include:

    (1) Compared to liquid fueled rockets, less stable thrust at larger scales (may shake the spacecraft too much).

    (2) Compared to liquid fueled rockets, less predictable total thrust over burn (may not achieved target delta-V).

    NitrousOxide:

    (1) Can’t be mechanically pumped at high pressures (e.g.: 800 PSI) because this is likely to cause rapid decomposition (causing an effect rather like an “explosion”).

    (2) Difficult to handle safely at high pressures, and there isn’t good public literature on how to mitigate this hazard.

    (3) (Benefit) For low performance applications, NitrousOxide can self pressurize.

    (4) (Benefit) At low pressure, NitrousOxide is relatively safe.

    Liquid rockets:

    If I were making a suborbital rocket plane from scratch, I would use a liquid rocket engine, either RP-1/LOX or Methane/LOX.

    Liquids, whether both fuel and oxidizer (liquid engine) or just oxidizer (hybrid), must be delivered to the rocket engine at slightly above operating rocket chamber pressure. There are two basic ways to achieve this:

    (1) Use higher pressure tanks than can handle the engine chamber pressure (this makes the tanks heavy). Use another very high pressure tank to hold a very high pressure inert gas (e.g.: He). Use the very high pressure He through a regulator to displace the liquids in the high pressure tanks as they are used up by the engine.

    (2) Use lower pressure (lighter) tanks with mechanical pumps to pump the liquids up to engine pressure. A number of different power sources for the pumps might be used: gas generator, staged combustion, battery electric, tapoff, piston… Inert gas pressurizing is still required to displace the liquid, but it isn’t nearly as much since it is lower pressure. Disadvantage: Complex mechanical pumps have more failure modes. Advantage: Mechanical pumps are the only practical solution for the highest engine chamber pressures (higher performing engines).

    Why did VG choose a hybrid rocket motor?

    I think it is mainly because the successful SpaceShipOne used a hybrid rocket motor (though it was much smaller) and that VG felt it was good PR to stay with that design despite the engineering challenges of scaling the engine up for SpaceShipTwo. Why did Burt Rutan pick a hybrid for SpaceShipOne? There is a public story about him watching a video of a liquid engine exploding and another one of a hybrid engine performing as planned – that plus the theoretical simplicity of the hybrid may be what inspired him to make the selection.

    Why did they pick NitrousOxide for the oxidizer? I think it may have been presumed safe based on its ubiquitous low pressure use, but the reality turned out to be more complicated than initially thought.

  • Sorry, Nathan, but the answer is too complex to make it through the spam filter… (3 tries now)

  • Thanks to Doug for “de spamming” my long winded Hybrid vs. Liquid post! Sorry there are copies due to my not realizing they were being blocked. : )

  • Douglas Messier

    They got caught in the automatic spam filter. I’m glad you mentioned it. I probably wouldn’t have seen them otherwise.