Image credit KGET 17. Notice workers circled in red for scale.
A series of still images from an upcoming tv news story about Stratolaunch Systems has been released, providing a rare glimpse into the project. The original Aviation Week article, with more images, is here.
Background and Analysis
One of the least visible launch development programs underway at the moment is Paul Allen’s Stratolaunch Systems. After offering a few artist concepts of it massive twin fuselage carrier aircraft and its original intended rocket, a modified SpaceX Falcon 5, the program got underway without any of the publicity and hype which surrounded its smaller winged counterpart, Virgin Galactic’s SpaceShipTwo rocketplane and White Knight carrier aircraft.
Changes soon came, with the substitution of Orbital Sciences for SpaceX as the booster supplier. The switch occurred after SpaceX indicated it did not want to interrupt production of the Falcon line with the type of structural changes which would be required for a booster to be carried to altitude horizontally rather than launched vertically. The new booster, eventually named Thunderbolt, and not Pegasus II as some has speculated, would consist of two solid fueled stages built by ATK, (topped?) with a liquid fueled third stage powered by two RL-10C hydrogen/oxygen engines.
Eventually, the carrier aircraft got a name as well, “Roc” after the mythic giant bird of prey. And it is certainly of mythic proportions. Powered by six 747 engines, the twin fuselage aircraft being built by Scaled Composites will have a wingspan of 385 feet, eclipsing the Airbus A380 by 123 feet. Or, in the uniquely American unit of measurement, the football field, a Roc perched on the 50 yard line would have its wings overlap the goal posts by 15 feet per side. In other words, longer even than Auburn cornerback Chris Davis ran back Alabama’s missed field goal attempt in the closing second of the 2013 Iron Bowl.
For all its impressive size however, there is still a very real question as to what market StratoLaunch will be able to serve, particularly with the Thunderbolt booster. With a targeted capacity of 13,500 lbs. to 220 nautical mile orbit, the Thunderbolt will fit into the traditional medium class launch category. As an alternate or successor to the Orbital ATK Antares, the air launched booster will offer the clear advantage of all weather, any orbit capability. Compared to the frequently problematical conditions, some self imposed, which afflict Cape Canaveral, Stratolaunch Systems will fit a niche, but at what price?
Even gaining the benefits of reduced overhead for the first two stages from the Orbital ATK merger, the Thunderbolt rocket may prove more a blast from the past than a cutting edge strike out of clear blue sky. Fully expendable and powered by a pair of very expensive Aerojet Rocketdyne RL10-C upper stage engines, which even ULA is seeking to replace for its future launch vehicles, it is difficult to see how it will fit into a market where it will likely have to compete against a partially reusable Falcon 9 with launch locations on three coasts.
Given the investment required to produce the world’s largest airplane, it seems that much like the mythical creature for which it is named, this Roc will ultimately carry aloft more than one type of “prey.” Could it eventually prove the basis for a fully reusable two stage system?
The September 30th, 2014 press release from Sierra Nevada Corporation that it is considering a scaled down version of its Dream Chaser space plane to be carried by Stratolaunch is one possibility and a step in the direction of reusability, albeit one which overlooks the booster itself.
Still, with all that carrying capacity, and the world of launch development as fluid as it has ever been, it would be more than a little surprising if someone, somewhere, wasn’t crunching the numbers on the giant aircraft and wondering “What if….?”