WASHINGTON — The U.S. Army’s desire to deploy swarms of tiny satellites for various tactical missions is one of the reasons it began development two years ago of what would be the United States’ smallest orbital launch vehicle, designed to put payloads of about 20 kilograms into space, government and industry officials said.
The Army Space and Missile Defense Command (SMDC) in Huntsville, Ala., conceived the Multipurpose Nanomissile system as a liquid-fueled core booster augmented by various strap-on solid-rocket motors. Standing just a little taller than a basketball hoop, the rocket’s modularity could make it useful not only as a launch vehicle but potentially a missile defense target, sounding rocket and hypersonic test vehicle as well, John London, SMDC’s manager for nanosatellite technology programs, said. It will also be a good way to make use of aging tactical solid-rocket motors that would otherwise be decommissioned, London said in a July 29 interview.
The Army had not built a satellite in nearly 50 years until recently starting a handful of experimental satellite programs. Rather than building a small number of very expensive satellites as the Air Force does, the Army is interested in large, cheap constellations of spacecraft that can be easily replaced.
“The interest we have in the orbital part is that these nanosatellites we’re building have price points that are between $300,000 and $1 million per satellite,” London said. “One of the reasons we like satellites of this class is we can afford to put a lot of them up there to where the entire constellation is still relatively inexpensive. If one satellite up there fails, and I need to replace it with a $300,000 satellite in a very specific orbit, and the lowest cost launch vehicle out there is at least 30 to 50 times the cost of that spacecraft, that won’t work.”
To develop the Multipurpose Nanomissile System’s core booster, the Army in 2008 contracted with Colsa Corp. and Dynetics Corp., both based in Huntsville. The Army has spend about $7 million to date on the Multipurpose Nanomissile System and needs about $17 million more to complete development, London said.
The booster is 3.6 meters tall and 60 centimeters in diameter. Dynetics is mainly responsible for the booster’s propulsion system, which uses a nitrous oxide-ethane blend to produce 3,000 pounds of thrust, Steve Cook, Dynetics’ director of space technologies, said in an Aug. 4 interview. If completed, it will be the smallest launch vehicle available in the United States, he said.
The team recently completed its sixth static fire test of the propulsion system, which lasted 60 seconds, about half of a full burn, Cook said. The companies are in negotiations with the Army to extend the companies’ work and conduct a first unguided suborbital booster flight test about in about a year, he said.
In its most basic configurations, Multipurpose Nanomissiles could be purchased for as little as $150,000 apiece if they are being produced in quantity, London said. In a launch vehicle configuration, the liquid core booster alone could carry payloads of about 10 kilograms to low Earth orbit, and if fully outfitted with solid-rocket motors for additional thrust, the payload capacity is around 23 kilograms, London said. The estimated production cost for the launch vehicle configuration is around $1 million, not including range and payload integration costs, he said.
The Army’s approach to the Multipurpose Nanomissile program is unlike that of traditional government rocket programs, said Cook, a former NASA official who led the development of the U.S. space agency’s Ares family of rockets before resigning last summer. Whereas mission assurance is the ultimate goal of other rockets, a low price point is the driving force for this program. That dictates not only that the rocket be very small in size, but also the use of inexpensive components such as stainless steel fuel tanks instead composite or aluminum ones, Cook said.