Finding Cheaper Ways to Get to Space

November 16, 2014 – A few years ago Paul Allen, of Microsoft and X-Prize fame, proposed buying two Boeing 747s, removing an outside wing on one and an inside wing on the other and joining them together using a central spar which would be strong enough to hold a suspended chemical rocket beneath. This would replace having to launch payloads into low-Earth orbit from Earth’s surface.

Since Allen first proposed this scheme it has evolved to become Stratolaunch Systems, a project to design an airframe on a scale much larger than the White Knight Two of Virgin Galactic. Yet to be realized, what Allen’s air launch system (seen below) could do is go well beyond the sub-orbital limits of Sir Richard Branson’s space tourism project which last month came to a halt because of a fatal accident.

Stratolaunch could put humans into low-Earth orbit at high frequency and low cost when compared to ground-based rockets. Current designs will be capable of low-Earth delivery of payloads up to 6,800 kilograms (approximately 15,000 pounds), and smaller satellites to geostationary orbits. First flight tests of the airframe and rocket launch system are planned for 2016.

Air launching of payloads is not a new idea. NASA and the American military have toyed with this idea in the past. Experimental launches from commercial and military aircraft go back to the 1990s. NASA has even proposed the use of high altitude gliders to serve as platforms for air launches.

The latest NASA creation is the Towed Glider Air-Launch System (TGALS).  Like White Knight Two and the Stratolaunch concept, TGALS uses a twin-fuselage joined by a central spar. Towed behind an airplane the glider reaches altitudes of  12,200 meters (40,000 feet). The glider, with a rocket attached is then released to serve as the launch platform.

On October 21 of this year NASA successfully tested a 1/3 scale prototype of the glider (8.2-meter, 27-foot wing span  and seen in the picture above) with no rocket payload aboard. The pilot  on board reported that the glider flew flawlessly.

Built largely from commercial off-the-shelf materials (actually two gliders joined together by a central span) TGALS will eventually be tested carrying a full payload. A test launch is anticipated as early as 2015. Of course there are payload limitations to using a glider to launch satellites into low-Earth orbit this way, but for smaller packages, this may be the way to get to space.

And not to be outdone, Boeing, under contract with U.S. Defense Advanced Research Projects Agency (DARPA) is developing the Airborne Launch Assist Space Access (ALASA) program, an air launch system that can place a 45 kilogram (100 pound) micro-satellite into orbit for less than $1 million per mission. ALASA is designed to attach to the fuselage of an F-15E jet. Like NASA’s TGALS and Allen’s Stratoguard, ALASA would be released at 12,200 meters (40,000 feet) before firing its multi-stage launcher.

Meanwhile Paul Allen’s Stratoguard has joined forces with Orbital Sciences in the past month in the hope to realize his dream. Orbital has more previous experience with airborne space launch systems than any other company. Through its Pegasus, program it has flown 42 missions over the last 24 years using a commercial jetliner as a launch platform.

But Orbital is still dealing with the recent fallout from the launchpad explosion of its Antares rocket with Cygnus supply module aboard for the International Space Station. So I would guess Stratoguard may be shunted to the side for the moment.