What happend to the ROTON rotary rocket?

Whatever happened to the ROTON?

Easy question! Because I'm a friend of Tom Brosz, who worked
with Gary Hudson, on the project.


ANSWER: They ran out of money;
they then gave many of the components
[including rocket motor] to XCOR;
and Gary Hudson is currently working on a project involving used Titan rockets.

cheers.

It's a long story, and people here have accurately gotten pieces of it. Some other people have put out less-accurate stories, including a book that was out there for a while.

Note: All of the following is my own take on it, from my viewpoint at Rotary Rocket, and represents NO official statement, or even the opinions of other workers.

The original Roton concept was created by Bevin McKinney, and was a design that would propel itself into space using tip rockets spun on the end of a rotor, or as it would probably have ended up, a sort of supersonic propellor. The tip motors would be high-pressure liquid rockets, pumped by the centrifugal force of the rotor spinning. The rotor would be used for aerodynamic lift at the beginning of the flight, greatly enhancing performance. When the atmosphere ran out, the rotor would be tilted to allow the rockets to operate with downward thrust, with enough tilt to keep the spin going.

The synergy of the concept was impressive. The original design was a small unit targeted for the many hundreds of small satellites that were a big thing at the time.

Then, as has been pointed out, the small satellite market collapsed while the company was well under way. Our target niche vanished almost overnight, and at this stage of the game, NOBODY was looking at space tourism, something the small Roton was almost made for.

To save the company and concept, a major attempt was made to redesign and scale up for larger commercial payloads, up to and including comsats with their kick motors. Then the problems began. A rotor's lifting capacity varies (very roughly) with its area as you increase the size. But as you increase the size of a vehicle which is mostly propellant, its mass--a function of volume--increases much faster.

Relatively early in the game, it became apparent that a reasonably-sized rotor was no longer able to lift the larger vehicle off the ground with any efficiency. At one point, it was apparent that almost full rocket thrust, from much larger engines, directed downward, would be needed to augment the lift of a spinning rotor at ground level. Given this, integrating the launch engines with the rotor no longer made much sense. A decision was made to create a new engine package, at the base of the vehicle, which would launch under rocket thrust from the ground. The rotors became a system only used for the last phases of the landing, almost beside the point now, but at least saving the landing fuel and complex restart procedures that would have been required to land under rocket thrust.

This new engine, a large "carousel" of small chambers, was still centrifugally-pumped, with the entire engine spinning on its axis, and propellants fed through the axle at the center. A lot of work was done on this by talented engineers, and the concept was, and still is, sound. But the all-important Isp increase using aerodynamic lift, that had been an important feature of the original, smaller concept, was gone. We now had to force our way into space like any other rocket.

However, a larger vehicle, larger propulsion package, and other issues began to create financial problems. Items cost more than expected, and while this is not unusual, it can be a major issue if you're on a tight budget.

Attempts to raise money from more investors did not go well. At the time, we were competing with a healthy dot.com industry, and why put cash into something that will make you rich in five years when you can put your cash into something that will make you rich in a month? That, and the amounts required had grown with the vehicle size.

A test vehicle, the ATV, was built to test rotor-driven aerodynamic flight. This test program was only one of many required to develop the full vehicle, but it was seen as the most impressive possible on limited funds, and the test of the engine was many months away at best.

Main engine problems, a combination of technical hurdles and short funds, continued. Backoff positions were considered that used bell-nozzle engines (of various types) stuck up the Roton's backside. The Fastrac was way too heavy, and either a new engine would have to be developed, or something done with existing engines. One design actually had an NK-33 stuck up the center(!)

We had started out building a small, reusable vehicle to throw small Teledesic satellites into low orbit for very low cost.

Now, for all intents and purposes, we were now building the DC-Y, and we didn't have those kind of resources.

The ATV, built by Rutan's crack team, and wearing a surplus helicopter rotor outfitted with tip jets, was a great success. It had a spectacular rollout, and later low-altitude flight tests were successful.

But it didn't accomplish its second function: helping to raise funds. Sophisticated investors realized that the ATV tests were only a small part of the design, and wanted to see much more, particularly main engine tests. Reasonable enough, to be sure, but far beyond the funding we had in hand. Overhead was eating as much as research. We even tried to sell Richard Branson on the vehicle idea, but he passed. I figured that he would probably only come in after we had a real flight or two under our belts. Also reasonable enough, I suppose.

The money ran out, and we all dispersed. Many engineers did end up at XCOR, and are doing some good work there, which I am watching as enthusiastically as I am the efforts of other pioneers.

Scheduled high-altitude flights of the ATV were cancelled, deemed to be too risky for a project that looked doomed anyway. Contrary to some urban myths, nobody involved with Rotary Rocket walked away rich. I would know. And everyone involved in the project was doing their level best to carry it off, many of them far beyond what was expected of them.

Currently I'm working with Gary, Bevin, and a number of others on DARPA's FALCON project, and a NASA exploration contract. For the record, the Titan II work was part of our low-cost Alternate Access concept, but we didn't get the followon contract for it. Too bad...on its original schedule it would have been almost ready to fly to the ISS when the Columbia went down.

I would love to see the ATV preserved in a museum, but it would cost over $100,000 to move it. Certainly Scaled would be skilled enough to break it up and reassemble it, but that wouldn't be cheap either.

The above is oversimplified, and again, just from my own point of view. But maybe it clears a few things up.

tbrosz, thanks for the fascinating tidbit. Your first hand account of aviation history does much to enrich this board.

Rumor has it the Roton ATV will soon be displayed in front of the Voyager Restaurant at Mojave Airport, the nation's first inland spaceport.

Hmm. The front page at Mojave Airport Civilian Aerospace Test Center -- www.mojaveairport.com -- says "Next Flight of SpaceShipOne: To the Smithsonian!"

Does this mean the VERY next flight? What about the third rocket motor? Will it be going to the Smithsonian, too? Will the exhibit include the napkin with the sketch for #316?

it suprises me a little that they aren't going to use SpaceShipOne for tests relevant to SpaceShipTwo class vehicles. There is a lot of money to be made using an X-Prize vehicle to lift payloads formerly used by sounding rockets, and Rutan is not interested in being sidetracked by this, either.. Hopefully that fact might help some of the remaining teams secure whatever funding they need. There is plenty of market share to go around.

See, I'm figuring that he *really* wants SS1 in a museum. It's accomplished it's design goal -- convincing people that routine spaceflight is possible and attracting commercial investment. A contract has already been signed with Branson. Sure the design's safe, but what if it lands a little hard and is ruined?

Virgin Galactic does, of course, have the option of renting their craft for research.

And, really, SS1 was never intended to be used for any sort of commercial service. Voyager only flew a few times, you know, even though it could have been flown more often...

Or it could just be that he's got a nice streak and is giving other folks time to try to get research-oriented flights since he's got the funding he needs right now.

hmm. sorry, false alarm. Just catching up on the x prize news ... according to 'No experiments' for SpaceShipOne by Irene Mona Klotz in Mojave, California.

Before SpaceShipOne is retired, however, it has one very important mission left. It is to serve as the test flight vehicle for a new series of commercial passenger spaceliners that will be operated by Virgin Atlantic Airways.

"My gut tells me that the additional flying we may do on this airplane before it goes to the Air and Space Museum should be focused on developing the very best space tourism vehicle," Rutan said.

http://www.xprizenews.org/index.php?p=586