Graham Warwick/WASHINGTON DC

The US Defense Advanced Research Projects Agency (DARPA) plans to demonstrate a robotic spacecraft capable of refuelling, repairing or reconfiguring satellites in orbit.

If it is funded, the Advanced Space Transportation and Robotic Orbiter (ASTRO) technology demonstrator would be flown in late 2001.

With additional fuel delivered by a space tanker, it would be possible to manoeuvre military satellites between orbits, DARPA says, to reposition spacecraft to monitor crises, to avoid anti-satellite systems or to make it harder to hide activity from reconnaissance craft. A robotic vehicle could also be used to make on-orbit modular repairs and upgrades to appropriately designed satellites.

The first phase of the programme will look at novel launch techniques, including gas guns and small expendable and recoverable vehicles, able to launch payloads of less than 100kg at low cost. Payload concepts for refuelling, repair and reconfiguration missions will be examined, along with robotic space operations and modular serviceable satellite designs.

One concept is a small shuttle vehicle that would be boosted into a low-cost orbit from which it would manoeuvre to refuel a satellite before returning to earth to pick up more fuel.

If the $3 million first phase produces an economically viable and technically feasible approach, DARPA plans a $10 million second phase to develop the needed technologies and demonstrate the ASTRO concept in orbit.

The proposed schedule calls for DARPA to select the preferred ASTRO concept, including low-cost launch system and robotic transfer vehicle, in January next year, leading to a proof-of-concept ground demonstration in September next year and an on-orbit test in September 2001.

Source: Flight International