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What Happened to My Ride into Space?
Saturday was the 57th anniversary of the first satellite in orbit, the Soviet Sputnik. It was also (not coincidentally, because the date was chosen) the tenth anniversary of the winning of the Ansari X-Prize, a $10M award for the first vehicle to fly into space (i.e., above 100 kilometers altitude) twice within a period of two weeks. On that date, a decade ago, SpaceShipOne made its second flight into suborbit and claimed the money (technically, it wasn’t won until a day later, because one of the prize rules was that the pilot had to survive at least 24 hours after landing, presumably to ensure that the landing was sort of “safe”).
I attended the anniversary celebration in Mojave, with a lot of people more luminary than me. My old (in both senses of the word) friend Alan Boyle at NBC (who was also in attendance) has the story.
After that historic flight, many expected that rides would soon be available to the public, with Richard Branson’s promise to fund a commercial version of the winning vehicle. His company, Virgin Galactic, took millions of dollars in deposits, and announced that the first customers would fly three years later, in 2007. But it has been a decade, and no passengers have yet flown. Over at Popular Mechanics, Michael Belfiore has the story as to why the promise remains unfulfilled.
The pilot that day, Brian Binnie, is no longer with Scaled Composites, who built the spacecraft, and has gone to work next door for XCOR Aerospace, who is developing their own suborbital vehicle, the two-person Lynx. I stopped by XCOR on Saturday morning before the event to see how it was coming along, and it looks like they have all the major components (cockpit, wings) that have been holding them up, and appear to be on track for flying the first prototype in the next few months. In any event, apparently, Brian now feels free to discuss the issues of the program:
“The delay in SpaceShipTwo has not been the development of either of the vehicles,” Binnie says. “But the rocket motor has just been problematic from the get-go.”
Those problems start with scale. Binnie says the company’s original plan was simply to scale up the design of SpaceShipOne’s motor to fit the larger SpaceShipTwo. “That sounded good to us. Our name was Scaled,” Binnie says. “Basically an airframe was built betting that the propulsion system would meet the demands that the requirements [for SpaceShipTwo] offered.”
Scaled Composites lost the bet. Binnie says every part of the original motor design has had to be revised from the ground up. Take the nitrous oxide tank, which had to be bigger while maintaining a high internal pressure, with the additional requirement that it hold up over the course of the many flights expected during commercial operations. In 2007, a version of the tank exploded during a ground test, killing three Scaled employees. The tank has since been completely redesigned.
The synthetic-rubber solid fuel in the motor is another problem for SpaceShipTwo. “It was full of instabilities initially,” he says. “We had startup instabilities and we had end-of-burn instabilities.” Even on SpaceShipOne, the uneven rate at which the solid fuel burned produced uneven thrust. That problem worsened on SpaceShipTwo. While trying to fix the problem, Binnie says, “we did everything but break down and pray to God to show us the light of day.”
This has been the inside story for years, as Doug Messier over at Parabolic Arc has been steadfastly reporting from Mojave. I’ve heard the same thing from my own sources, but this might be the first time that someone formerly on the inside has gone on the record with it.
Basically, the late Jim Benson of SpaceDev (now part of the Sierra Nevada corporation, which finally seems to have given up on its own plans to use a hybrid motor for its Dream Chaser vehicle) sold Burt Rutan a bill of goods with the hybrid, with claims of simplicity and safety. In fact, as many of us told him at the time, he’d have been a lot better off purchasing a liquid engine from XCOR, but they didn’t have a sufficient track record at the time for him to think they could meet the deadline to win the prize. Then, once they’d (sort of) succeeded in flying something into space, they continued on with what they thought they knew. They’ve been in a sunk-cost trap ever since, unable to get themselves out of the hybrid-propulsion rut.
As I’ve long noted, the delays in the arrival of commercial spaceflight have been a combination of people who knew what to do not having money, and the people who had money not understanding the problem, and being too arrogant to listen to the veterans. Only now is the crucial combination of money and know how finally coming together. Note that Doug also has a video on the webcast of the event, with a lot of war stories from Burt, Branson, Peter Diamandis, Anousheh Ansari (who funded the prize and for whom it was named), a representative of Paul Allen (who funded Burt’s efforts) and the pilots. Burt in particular was (as usual) quite unplugged. It’s a little over an hour, I think, but quite entertaining for those interested in that history, with a lot of new info about those events. Note particularly the awkward group hug of Burt at the end, orchestrated by Sir Richard, after some oblique criticisms of the latter by the former with regard to management style.
[Tuesday-morning update]
Per discussion in comments, there seems to be some confusion about the difference between high-altitude flight, suborbital flight, and orbital flight. As anonymous points out, orbital flight requires a minimum speed to sustain the orbit, but while that is necessary, it is not a sufficient condition. In fact, a flight can be suborbital with the same speed (energy) as an orbital flight. The best or, at least, most rigorous way to define a “suborbit” is an orbit that intersects the atmosphere and/or surface of the planet. So if you launched straight up at orbital velocityspeed*, it would still be a suborbit, because it would (after an hour or two, I haven’t done the math) fall back to the ground. So while John’s numbers in terms of comparative energy are roughly correct for the particular vehicles being discussed here (XCOR Lynx and VG SpaceShipTwo), they can’t be generalized for any suborbital vehicle (e.g., a sounding rocket isn’t orbital, but it goes much higher than those passenger vehicles, often hundreds of kilometers in altitude).
The speed necessary to achieve orbit is partly a function of the mass of the body being orbited, but it is also a function of its diameter, and whether or not it has an atmosphere. If the earth were a point mass, an object tossed out at an altitude equivalent to the earth radius (that is ground level) would have very little velocity, but it would have a lot of potential energy. It would fall, gain speed, whip around the center and come back up to the person who had tossed it. That is, it would orbit. So even for the relatively low-energy suborbital vehicles discussed in this post, the reason that they’re not orbital is simply that the planet gets in the way.
One other interesting point is that, under the definition above, subsonic “parabolic” aircraft flights in the atmosphere, to offer half a minute or so of weightlessness (offered by the Zero G company), are suborbital flights, in terms of their trajectory. I put “parabolic” in quotes because in actuality, if properly flown, they are really elliptical sections, as all orbits and suborbits are. The parabola is just a close approximation if you assume a flat earth, which is a valid assumption for the short distances involved. Galileo did his original artillery tables based on flat earth, which is why beginning physics students model cannonball problems as parabolas, but modern long-range artillery has to account for the earth curvature, and it does calculate as elliptical trajectories.
Finally, one more extension. Ignoring the atmosphere, every artillery shell fired, every ball thrown or hit, every long jumper, every person who simply hops up into the air, is in a suborbit. The primary distinction for the vehicles discussed is that they are in a suborbit that reaches a specific altitude (at least a hundred kilometers to officially be in “space”), and leaves the atmosphere.
* I changed this, because orbital “velocity” implies a direction that would allow a sustained orbit. “Velocity” is a vector, with a direction (60 MPH, headed NW), while “speed” is the absolute value of it (60 MPH).
Image Credit: Flickr user Santosh Dawara.
Published in General
I’m still waiting for my hover board.
What about SpaceX? Is SpaceX’s more traditional rocket technology too expensive for space tourism?
At this point yes. I have see predictions of $60 million a launch with a reusable vehic to LEO. That is still $10 million a seat minimum. However, as things progress they may get cheaper.
So, doesn’y any of the blame for delay rest with meddling by the FAA?
I need a government agency to redirect my antipathy! I NEED IT!
;-)
No, that hasn’t been a problem at all.
That’s a separate issue. SpaceX delivers payload and people to orbit. The X-Prize, and this post, are about (much less costly) suborbital flight.
I know orbital flight is much more costly than sub-orbital flight, but I would think a trip to orbital flight might be worth the extra cost to a billionaire space tourist. It is more about economics than physics. How many customers are willing to pay $500K for 20 minutes? of sub-orbital flight vs. orbiting the earth for a couple days at $10M? Both prices are substantially more than the vast majority of people would ever be able to afford, so the economics might not be so bad if SpaceX can get their price down to the $10M level.
If sub-orbital flight is all that is desired, would a balloon based system (like the one that guy who set the skydiving record used) be even more economical?
Speaking for myself (if I ever became a billionaire), I would hesitate to pay $500K for a short sub-orbital trip (like dipping your toe into space), but I might pay $10 million to actually go into orbit. To each his own.
Does anybody know if the U-2 can be owned by a private entity? The U-2 is a well proven aircraft (it has been in service since 1955!) that cruises at 20 km (more than twice what commercial airliners fly at), and would seem to me it could be a cheap tourism option (say $20k for a few hour flight).
Burt Ruatan is a real life John Galt.
This is one of the saddest songs I know.
I asked one of my team about this. He wrote:
Yes, it costs less, and it’s more luxurious (there is a company planning to offer them in Arizona), but it doesn’t get all the way into space, and it doesn’t offer any weightlessness. Also, it’s not “sub-orbital” flight.
anonymous:
Did they have some kind of reaction-control system? How did they ensure proper orientation for entry?
If I remember my Chuck Yeager correctly, real progress was being made with Dyna-Soar program in the late 50s and early 60s, but Sputnik grabbed the headlines and everyone wanted something done now, so it was discontinued. Not sure if that’s accurate, but curious if that technology (reusable aircraft, landing rather than parachuting to earth) was/is involved here.
No, Dyna-Soar died in the sixties. It was a space plane, but was to go up on an expendable launcher. A more Yeager-like path would have been X-15 extensions and follow on.
Typically such a published value is either the service ceiling or the absolute ceiling, and is not applicable to the type of parabolic arc flights we are talking about.
For the nontechnical folks: In an oversimplified sense, there are basically two ways to climb in an aircraft. You can do a steady climb at a shallow angle maintaining roughly constant airspeed and use the engine’s power to gain altitude, or you can do a zoom climb at a steep angle and sacrifice airspeed for altitude. In general an aircraft’s ability to execute a steady climb decreases with altitude as the air becomes thinner and both the engines and wings become less effective. The ability to zoom climb depends mostly on its initial airspeed and how fast it can pull up.
The standard definition of absolute ceiling is the maximum altitude at which the aircraft can maintain level flight. This means the maximum steady climb rate is zero. Note that the absolute ceiling can never be reached using a steady climb. However, it can easily be exceeded by pulling up into a zoom climb, after which the aircraft will reach some maximum altitude, possibly stall, and then drop back down below the absolute ceiling until it recovers sufficient airspeed to level out again.
The service ceiling is the altitude at which the maximum steady rate of climb is 100 feet per minute. This is just a convention and that’s a little lower and a lot more practical than the absolute ceiling.
Any non-rocket aircraft that has flown over about 80 thousand feet (except the Blackbird) achieved it using a zoom climb.
Two quibbles:
The test of an idea is in the doing. Looking back its easy to spot dead ends, but never at the time. The guys who had the money knew what to do until it didn’t pan out. Don’t be quick to assume the other guys know what to do just because they haven’t had the money to test their ideas out.
Beginning physics students train on parabolas because the parabola equations are easy to solve. Any number of outmoded conventions have been discarded. We don’t write papers in Latin just because Newton did so.
Modern artillery only goes for the more correct equations because the guns shoot for miles and miles. On the scale of steel ball bearing lab experiments there’s no practical difference.
But those are, as I said, quibbles. In the end I’d really like to go into space too.
A lot of people (including me) told Burt (who had no experience with rocketry) not to use a hybrid, and we were even more adamant after he’d won the prize and was developing SpaceShipTwo. It was obvious to those of us in the business, at the time, that it was a terrible design choice. But I will confess to not realizing just how bad it was.