The U.S. Defense Advanced Research Projects Agency (DARPA) has a license to take on risky endeavors, which is appropriate: A novel experiment’s payoff potential often is inversely related to its chances of panning out. DARPA’s SwiftBroadband for Satellite, or SB-Sat, project stands out as a bit unusual in that respect.
SB-Sat aims to demonstrate that commercial satellite terminals designed for airborne applications can be converted for use aboard low Earth orbiting satellites, enabling the spacecraft to receive commands from and transmit data to almost anywhere on the ground in near real time. The commercial SwiftBroadband terminals operate with the geostationary orbiting Inmarsat 4 spacecraft, which provide global L-band links to mobile users. As far as DARPA undertakings go, the project seems relatively straightforward.
Another unusual aspect of SB-Sat is that it is being carried out jointly with the European Space Agency (ESA). As an often secretive defense technology development shop, DARPA is not well known for working closely with international partners, particularly civilian space agencies.
DARPA is providing $18 million to a contracting team led by Inmarsat of London and including Com Dev Europe and Broad Reach Engineering of Tempe, Ariz. ESA is providing 5 million euros ($7 million) to the same industrial consortium, but with Com Dev in the role of prime contractor. The plan is to have a space-qualified SwiftBroadband terminal ready to fly aboard an as yet unnamed low Earth orbiting satellite around 2014.
The SB-Sat project would, in effect, make the Inmarsat 4 system a commercial version of NASA’s Tracking and Data Relay Satellite System (TDRSS), which is used to transmit data to and from U.S. government spacecraft that are not in line-of-sight contact with a ground station. Inmarsat 4 is a narrowband system, so any service based on the SB-Sat experiment would not offer anything close to the capacity of government-owned relay systems like TDRSS, which handle huge data files from complex scientific and imaging satellites. But even a poor-man’s TDRSS would have plenty of real-world applications, including direct satellite tasking from remote locations and immediate downloads of sample data that could, among other things, allow users to determine the quality or utility of a collected image.
SB-Sat represents a combination of creative thinking and resourcefulness that will come in handy as DARPA seeks to incubate new capabilities during the lean budget years ahead. DARPA and ESA are not only leveraging one another’s resources, they are also leveraging private sector investments. The result of the relatively modest overall expenditure could be a new service that’s of immediate use not only to governments but also to commercial satellite operators.
DARPA in recent years has thrown considerable sums of money at various projects that experience would suggest had little to no chance of succeeding with the budgets that were made available. One example is the Responsive Access, Small Cargo, Affordable Launch program, intended to produce a launch system based in part on a converted aircraft that would be capable of lofting satellites weighing up to 150 kilograms. It looked farfetched, especially under DARPA’s schedule and estimated $88 million price tag, and it was — the project was abandoned after two years when technical realities caused cost projections to soar.
While it is part of DARPA’s core mission to be aggressive in pushing technology, without fear of failure’s repercussions, the current budgetary environment calls for adding less-ambitious projects to the mix that leverage existing capabilities and spread the investment to the extent feasible. SB-Sat is a good example of both and demonstrates that innovation need not be synonymous with high risk. Given the number of commercial satellite projects getting off the ground in the coming months and years — including the replenishment of the low Earth orbit mobile communications constellations operated by Globalstar, Iridium and Orbcomm — the opportunity for DARPA and others to pursue similar kinds of projects may never be greater.
