SpaceShipTwo Can’t Reach 100 Km Boundary of Space

Looking back as SpaceShipTwo's rocket engine fires during the third powered flight. (Credit: Virgin Galactic)
Looking back as SpaceShipTwo’s rocket engine fires during the third powered flight. (Credit: Virgin Galactic)

By Douglas Messier
Parabolic Arc Managing Editor

One of the more interesting revelations that came out of the London Sunday Times story I co-wrote on WhiteKnightTwo’s wing cracks was that Virgin Galactic finally acknowledged that SpaceShipTwo won’t be able to reach the internationally recognized boundary of space, which is 100 km (62 miles).

So, just how high can this first version of SpaceShipTwo go? Virgin now says the spacecraft will be able to exceed 50 miles. Other sources I know are far less confident it will be able to reach that high.

The reason is simple: the Sierra Nevada Corporation hybrid rubber-nitrous oxide engine they are using performs very poorly. The vibrations and oscillations in the version they used for the first three test flights would have torn the ship apart well if it had been fired for anywhere near full duration of about a minute.

So, remember how after the first powered flight in April 2013 when Virgin Group Founder Richard Branson declared that engineers had finally perfected the engine, and he promised to fly into space on Christmas Day dressed as Santa Claus? Utter bollocks. It had no relation to anything happening behind the scenes.

But, Virgin Galactic has a plan to fix it. Sources tell me engineers have modified SpaceShipTwo with additional tanks to hold helium that will be to dampen out the oscillations and vibrations. However, the additional weight will at least partially offset the extra engine performance. It also will reduce the number of passengers in the back from six to four, sources tell me.

Will the ship be able to reach 50 miles? In theory, yes. In practice…we’ll have to wait for flight testing to resume sometime later this year to find out.

In short, after nearly a decade of effort, Virgin Galactic has a ship that can’t even reach the same altitude as its predecessor, SpaceShipOne. This despite having advertised and sold tickets based upon a promised altitude of 100 km or more and about five minutes of weightlessness. (The actual contract with passengers says a minimum of 50 miles, but that wasn’t widely known, much less publicized.)

Further, the spaceship will carry one-third fewer passengers than originally planned. Or to put it another way, it will carry two more passengers than SpaceShipOne would have carried if it had ever been put into commercial service. Of course, SpaceShipTwo is much roomier than its predecessor, so passengers will be able to float around.

But, no matter. Virgin Galactic is pressing forward and still targeting the 100 km target at some point in the future. Meanwhile, the company expects customers to be happy with exceeding 50 miles, which in truth would still be a significant accomplishment.

Earlier this week, CEO George Whitesides said in the following statement to Gizmodo:

“NASA and the US Air Force have a long tradition of celebrating everything above 50 miles (~80km) as spaceflight, and we look forward to joining those ranks soon as we push onward and upward. We are still targeting 100km. As we have always noted, we will have to prove our numerical predictions via test flights as we continue through the latter phase of the test program. Like cars, planes, and every other type of vehicle designed by humans, we expect our vehicle design and performance to evolve and improve over time.

“When SpaceShipTwo reaches space for the first time—which we expect will happen just a few short months from now—it will become one a very small number of vehicles to have ever done so, enabling us to commence services as the world’s first commercial spaceline; our current timetable has Richard’s flight taking place around the end of the year.”

How thrilled customers will be with the change — which will likely mean less zero-g time — remains to be seen. Despite what their passenger contract says, Virgin Galactic had no trouble marketing the experience as something more than it will deliver.

This is rocket science, and it’s not surprising that something like this could happen. But, why did the customers have to find out about it from the newspaper? Astronaut relations should be more than just an endless stream of assurances that all is well and attacks on the media.

  • Carolynne Campbell

    I figured the extra weight would be He tanks, which are pressure-vessels and therefore heavy. However more He, on it’s own wouldn’t be a great damper. To really do the job, they would need a bladder in the tank. Any idea if that’s what has been done?
    If so – that’s more weight, plus a big heavy regulator……
    Four passengers means a 33% loss in revenue per flight. What does that do to the business model?

  • Thanks for your reporting on the issue. Those engines really were an unfortunate choice. If they had chosen liquids they would be flying suborbitally by now.

    Bob Clark

  • savuporo

    Surely, the peak altitude depends on the payload ? If they fly with one passenger, it should be able to go higher.

  • Glorfindel

    Whiteside’s spin makes him sound like a con-man.

  • therealdmt

    If I were a passenger, I’d be sorely disappointed about not reaching the advertised 100km, considering the small fortune involved (not to mention the time value of money). However, a much, much, MUCH bigger concern would be safety. Whitesides and Branson and family going up first would help alleviate those fears, but it looks like large nitrous oxide-using engines may be inherently dangerous, which is concerning to say the least.

    Anyway, I would be THRILLED however to find out that less passengers would be going up with me. Having that nice big semi-empty cabin to float around in without a bunch of rich strangers kicking me in the head when I’m trying to look out a window or posing for a picture, etc. would more than make up for missing the rather arbitrary target of 100km.

    But that the rocket motor is basically safe (or not), that would trump all.

  • Terry Stetler

    Then you’re better off in a Lynx save for floating – you at least have a front row seat.

  • Terry Stetler

    Makes one wonder if there’s behind the scenes work to adapt a VG LauncherOne ‘Newton’ engine variant.

  • Michael Vaicaitis

    Seems to me the main the reasons for going on SS2 are: 1) to go to “space” and be able to say so, and 2) the view.

    With SS2 now at $250,000, there might be better value options.

    From XCOR website:
    “This two-seat, piloted space transport vehicle will take humans and payloads on a half-hour suborbital flight to 100 km…”
    “Lynx suborbital flight tickets are now available. A ticket aboard Lynx Mark I is $95,000 per flight and Lynx Mark II is $100,000 per flight”

    From wikipedia page for ZERO-G Corporation (vomit comet):
    “A flight lasts 90 to 100 minutes, and consists of fifteen parabolas, each of which simulates about 30 seconds of reduced gravity: one that simulates Martian gravity (one third of Earth’s), two that simulate Lunar gravity (one sixth of Earth’s), and 12 that simulate weightlessness.”
    “As of May 2013, the price of a flight for a single passenger is USD $4,950 plus tax.”

    You could take two trips each in Lynx AND a vomit comet and have $40,000 in change for the price of one trip on SS2.

  • Carolynne Campbell

    This is a company who describes Nitrous Oxide as ‘Safe, stable and benign’, on the website which advertises their services, Three people died in one accident and the test stand was destroyed in another a year ago. They know from their own direct experience that the claim is untrue.
    I do wish someone, in a public forum would ask Whitesides if he stands by those claims. There is no ‘good’ answer to the question.
    I’ve worked with the stuff for over a decade. I still work with it. Do I think it’s ‘Safe stable and benign’? No. I know better. From direct experience.
    There is no such thing as a ‘safe’ rocket, but some are much safer than others’
    I’d rather ride LOX any day!

  • Douglas Messier

    It’s not good for the business model. Not only are you losing money per flight with the reduced passenger numbers, helium is extremely expensive.

    The margins on the flights have just gotten worse over the years. Throw in the enormous cost, and I don’t know if Virgin will make money off this program. They say otherwise, but there are folks with serious doubts.

  • Douglas Messier

    Yes, probably.

    The point is that there’s a 33 percent decline in ticket revenues per flight ($400,000 to $500,000) and an increase in cost for the helium (not cheap). That’s a tough blow.

  • Douglas Messier

    The interesting thing was how Branson announced a 25 percent increase in ticket prices the day of the first powered flight. Went from $200,000 to $250,000. Part of it was to get late adopters — people who were waiting to see if the engine worked. There was a week or something like that for them to get tickets at the lower price.

    But it was, hey it works and I’m going to space by the end of the year, buy your tickets now. The reality behind the engine they had was different. They couldn’t get to space with that engine, and they were still searching for options on how to make it work.

  • Nickolai

    I think XCOR’s initial flights on the Mark I will be <100km as well

  • Greg Zsidisin

    Maybe this is a job for Elon. 🙂 Of course, they’re probably too far across the stream to switch horses.

  • cdevboy

    Don’t forget the fees that have been promised to the people of New Mexico for use of Spaceport America which they paid for. Is the Fee based on launches or number of people launched?

  • cdevboy

    I would have never paid in advance for a situation like this. Let them fly, then buy a ticket. All those people who paid the 25k have gotten no interest all these years. To all those rich people I say ask for a refund and forget about the bragging rights of being a ticket holder. Eating crow is not that expensive. They never should have gotten in bed with an establishment aerospace company and pushed Burt Rutan out.

  • patb2009

    Helium isn’t that expensive. It’s about $250/MC
    The tankage and design work is going to be the expensive part

  • patb2009

    yes, but it’s not like you think. Any aircraft has Dry structure weight, Fuel weight and Payload weight. Payload is both Pilots and passengers. International flights will sometimes eliminate passengers to meet range and safety requirements, but, it’s a tough fix.

  • savuporo

    They could borrow a trampoline to compensate.

  • therealdmt

    Basically, it was your posts that made me aware of the issue, and made me feel like this might be an inherently unsafe (or not very safe) vehicle.

    Before that, I was just of the opinion of, well, if they certify it, it must be pretty safe. I know from my experience in aviation that getting FAA certification for a new aircraft is very involved and certified aircraft are in a whole different work from uncertified aircraft (experimental category aircraft, such as most of Rutan’s designs fall under, actually) in terms of saftey and things working within certain parameters. But, what does the FAA know about hybrid rocket engines? Probably mostly what you tell them. Certifying spacecraft will be a new area for them too.

  • Carolynne Campbell

    Unfortunately the legislation does not require ‘Certification’. It requires ‘a license’, when it comes to spacecraft. There is no inspection or verification required.
    The issue is less clear regarding White Knight 2.

  • Dave Salt

    I believe the key ‘safety’ factor here is storage/operating pressure and that this was reduced after the 2007 fatalities, which also reduced engine’s performance. I’m not sure if the reduced pressure is ‘safe’ but I’m sure they’ll claim it’s ‘safer’.

  • Foliobook

    Does explain why RB has said he will make his first flight with his son, as I suspected, SS2 can’t lift a full passenger complement. Flight must also be pretty hairy with the vibration described.

    VG has always said that the future flight cost would come down over time, presumably this is less and less likely, though maybe if there was a new engine technology eventually (liquid fuel) maybe lower costs and better performance would be achieved.

    The question is my mind about the business model. New Mexico has been counting on the long term sustainability of the tourist business model, the difficulty of building the rocket and presumably of a rapid turnaround for repeat flights questions the sustainability.

    It will be interesting to see whether the Spaceport authority can raise the money for the southern access road given this new information. It makes further large investment by the state rather difficult I’d have thought. Meanwhile the inhabitants of Truth or Consequences hope that road is never built.

    The burning question we should all be asking… will Lady Gaga still appear in 2015? 🙂

  • Douglas Messier

    No certification, only licensing. Passengers fly under an informed consent regime.

    One VG passenger I’ve talked to doesn’t think that will be a very useful regime. The person isn’t sure how informative the company will be about risks because it hasn’t been very candid about the delays and problems to date. Informed consent doesn’t place any restrictions on what companies can say in their marketing and promotional campaigns.

    If you’re in the space industry, you have a pretty good idea of the risks. If you’re not, you could go into it thinking it’s a lot safer than it is.

  • Douglas Messier

    Mixed signals on that. At one point last year, they were looking to adapt the liquid Newton engine for SS2. Then that seems to have been taken off the table. But, more recently VG’s Mark Butler was down in Las Cruces and seemed to imply their were going to do that .

  • Dennis

    Well, I wouldn’t hope so 😛 Surely, SpaceX could probably build a system that WILL get SS2 to space, but why would they. That would require a R&D program, teststands, people to hire… and for what? A distraction from what SpaceX’s goal is!

    There is a reason they backed out of that Stratolaunch project as well! It just doesn’t fit in with their agenda!

  • Abdul M. Ismail

    Doug – out of curiosity, have you ever looked into why AMROC’s hybrid (from the 1990s) was never successful? Was it technical or business? The answer to this may explain why Virgin Galactic are experiencing so many technical difficulties because AMROC, as you may know, declared bankruptcy and the late Jim Benson’s SpaceDev bought the technology. I believe Scaled Composites then bought the technology from SpaceDev.

    While I see the logic of buying technology because it cuts development cost and drastically reduces to-market lead time; surely Virgin’s propulsion engineers should have performed a detailed trade-off in order to determine if the concept would be feasible for their specific application. I find this bizarre and it seems that someone succeeded in pulling the wool over Branson’s eyes who has also been naive to trust his “yes-sir” employees. His mistake could have been resolved by employing technically minded Devil’s Advocates to ensure he doesn’t make himself look like a fool by making promises he can’t keep.

    From a technical perspective, the reduction of propulsion system oscillation can typically be achieved by injecting a low molecular energy fuel. They use helium but methane can also be used. They could also replace aluminium (or aluminum, as you say) powder with magnesium powder to ensure complete combustion. The problem there is that the latter is less energetic than the former so the system won’t deliver the desired performance. One final method would be to reduce the aluminium metal particle size within the fuel grain. This allows for a faster burn rate resulting in lower oscillations and higher energy but the vehicle’s acceleration would increase which may prove uncomfortable for the passengers.

    Many highlight hybrids as the “best of both worlds” but what they don’t point out is that they can also be the “worst of both worlds” too.

  • ThomasLMatula

    There is an interview in the Scotsman with the Chief Test Pilot, David Mackay, who is from Scotland. For what its worth he estimates there will be three test flights this summer before flight testing is finished.

    Sunday 18th May 2014

    The Scotsman flying Virgin’s SpaceShipTwo


  • Douglas Messier

    That’s a very aggressive schedule that I believe is a result of a need to get Branson into space this year. My sources say that they need to under the agreement with Aabar. Virgin denies the claim.

  • Douglas Messier

    Alan Boyle did a story in which he gingerly tiptoed around most of the major issues:

    This is basically focused on where space begins and has little about the engine issues or how realistic VG’s goal of reaching 62 miles is at this point, which is now nearly a decade into the program.

    The reason is that Boyle’s parent company is in business with Virgin Galactic, with the goal of promoting Branson’s flight. This is a strategy Virgin used before. It had a previous exclusive agreement with National Geographic earlier in the development process.

    NBCUniversal has established a multi-platform partnership with Virgin Galactic to track the development of SpaceShipTwo and televise its inaugural commercial spaceflight.

  • Carolynne Campbell

    Interesting points! My understanding is Amroc went into liquidation, its technical assets were sold to Spacedev, who sold the N2O hybrid idea to Burt Rutan. Much later,,Sierra Nevada (the present propulsion contractor) bought Spacedev. Amroc had its best success with LOX hybrids, which seemed to work quite well.
    Making the fuel grain more and more energetic kind of defeats the idea of a hybrid – but it’s one solution.
    Helium is not fuel -it’s pressurant. Methane injection would improve performance -but then why not just dispense with the fuel-grain and build a methane bi-prop?
    Mixing methane with the N2O is not a good idea.

  • patb2009

    Given the spaceport is at coming together, perhaps,
    they could host Burning Man or some other big festivals while they are waiting. The benefit there is the facilities will give you an anchor for showers, cooking, fire/safety,

  • patb2009

    The hard part of a rocket engine isn’t the fuel system, it’s the
    oxidizer system. We have a century and a half experience with fuel systems. (Kerosene, Diesel, Propane, Methane, Butane, Ethane, Gasoline, Turpentine,alcohol,,,,,) But Oxidizer systems those are always touchy and tricky. LOX clean and OX clean are important.

  • patb2009

    SpaceShip one flew 4 times building up the experience before the X Prize trials. It was a very aggressive program. 6 flights in 10 months.

  • Curt

    Mr. Messier,
    VG has been experiencing more than just rocket motor
    whether it be rubber or plastic motor. Many huge technical issues VG
    must overcome are flight control systems, more safety and redundancy
    systems, feather actuators, weight growth and performance, etc. In
    particular, both SS2 and WK2 have the exact same flight control systems
    designed by Scaled with pulleys and cables and the test reports by
    Scaled years ago shows more than half of 15 items in the report failed

    Scaled never have the funding to redesign the flight
    control systems properly and they got away with it because of their
    prototype licensing.

    As for the weight growth, SS2 Serial 001
    built and flight test by Scaled and its weight has growth so much that
    VG cannot carry 6 passengers because of additional Helium tanks in the
    wings. It is projected to only carry 3 passengers at most and they have
    to limit the weight of male passengers to lower than 200 lbs and female
    passengers to lower than 150 lbs. The industry standard weight for
    each passenger is 200 lbs which was what VG had hope for.

    engineers had advice VG to not carry passengers on SS2 Serial 001
    because of weight growth but VG didn’t listen because they do not have
    experience or expertise to design, build and operate SS2. To make
    matter worse, VG is building the exact copy of SS2 Serial 002 as 001.
    They also planning to build Serial 003 to be fitted with liquid motor
    which is currently in development by VG internal funding if they are
    successful with both SS2 serial 001 and 002.

    My gut feeling is SS2-001 will never achieve all it’s goal and so VG can never be successful to carry passengers up to space.

    VG is currently running into regulatory issues with FAA. FAA will
    never issued VG commercial licenses to operate out of Spaceport because
    of lack of flight test data and AST-400 is way too general. It needs to
    develop in much more details for safety systems. FAA was counting on
    VG to supply and develop more flight test data since VG is the first to
    develop space tourism. VG will never reveal to their future astronauts
    about safety consent of SS2.

  • George

    The X-15 was in space over 46 years ago with engines that work.

    Why people are comparing space flights to airplane flights, e.g., the Wright Brothers is ridiculous, like comparing apples to oranges.

    That being said, Virgin Galactic has not come close to achieving the speed or altitude that is needed and they have only had two pilots in the SpaceShipTwo, not two pilots and 6 passengers. And, suborbital spaceflight has already been done by the Air Force over 50 years ago with the X-15.

    Virgin Galactic’s SpaceShipTwo’s goal is to reach an apogee (i.e., the point in the orbit of a heavenly body, especially the moon, or of a man-made satellite at which it is farthest from the earth) of 110 km (68.3508 mi) in the lower thermosphere at a speed of 2,600 mph. The thermosphere is directly above the mesosphere and below the exosphere. It extends from about 90 km (56 miles) to between 500 and 1,000 km (311 to 621 miles) above our planet, 10 km (6.21370 mi) higher than the Kármán line. The SpaceShipTwo will then freefall back to earth so that its passengers can feel about 4-5 minutes of actual freefall without the feeling of gravity and to see the curvature of the earth.

    “The Kármán line is an artificial boundary in Earth’s atmosphere that divides space missions from aeronautics missions — passing the line turns a run-of-the-mill pilot into an astronaut. And this obscure boundary may become extremely important as we enter the era of space tourism. A plane, aircraft, or other object relies on the density of the atmosphere to keep it aloft. The atmosphere thins as the distance from Earth increases, forcing a craft to increase velocity in order to stay airborne. This push and pull can be illustrated by an equation proposed by Theodore von Kármán, with the eponymous line becoming the distance from the planet at which a craft must meet or exceed orbital velocity in order to prevent a loss of altitude. Kármán rounded his initial calculated result to 100 kilometers (i.e., 328,084 feet or 62.1371 miles), and, in the process, selected the boundary by which pilots and passengers become astronauts.”

    At this height, you cannot rely on the atmosphere to keep your airplane or spaceplane afloat; air is virtually nonexistent at this point. Wings on a plane are of no use. It takes a speed of 17,000 mph to safely orbit the earth beyond the Karman line, which can only be done with rocket power.

    What is the highest and fastest SpaceShipTwo has flown?

    “in the skies above California’s Mojave Air and Space Port on January 10, 2014, the rocket-powered commercial spaceliner, known as SpaceShipTwo, attained a maximum altitude of 71,000 feet (44.12 miles) at a top speed of Mach 1.4 (1,065.68 mph – miles per hour) — 1.4 times the speed of sound, which is 761.2 mph at sea level.” SpaceShipTwo has never flown higher than 50 miles. SpaceShipTwo needs to fly 18.0171 miles higher to reach the Karman line; and; it also needs to fly 1,534 mph faster or 1.49 times faster than it has ever flown; and, that was with only two pilots, not two pilots and 6 passengers. SpaceShipTwo is not capable of doing that and many more people will be murdered for nothing but Sir Richard Branson’s ego.

    Wow, how impressive. The X-15 had 13 flights beginning on July 17, 1962 and ending on August 21, 1968 that reached higher than 50 miles, which is an altitude yet to be reached by SpaceShipTwo. So the X-15 did it over 51 ½ years ago. Richard Branson’s Virgin Galactic is proving nothing except that Richard Branson suffers from egomania, megalomania and delusions of grandeur.

    “As of 2014, the X-15 holds the official world record for the highest speed ever reached by a manned, powered aircraft. Its maximum speed was 4,520 miles per hour (7,274 km/h)”, which occurred on November 18, 1966 and an altitude of 18.7 miles – 47 years earlier than Virgin Galactic reached a mere speed of 761 mph, or a mere 16.8% of the top speed of the X-15 47 years earlier. The highest altitude flight made by the X-15 occurred on August 22, 1963 when it reached at altitude of 67 miles, which is 152% (67 miles divided by 44.12 miles) higher than the SpaceShip Two’s record of 44.12 miles.

    Again, SpaceShipTwo will never achieve this feat and run out of money soon. I just wonder how many more test pilots will have to die unnecessarily before Branson gets off his ego trip.

  • Abdul M. Ismail

    Just reviewing past communication.

    Out of curiosity, why do you say that mixing methane with NSO is not a good idea? As far as I’m aware, this is precisely what VG are going. They’re using helium for engine shut-down.