The Pentagon could assuage concerns that its automated satellite rendezvous experiments are aimed at developing space-based weapons by including international partners in the work, according to a critic of the experiment.

Theresa Hitchens, director of the Center for Defense Information, said there might be some validity to the U.S. Defense Department’s stated goals for the rendezvous experiments, such as extending the lives of satellites via on-orbit servicing. But skepticism about the cost-effectiveness of that concept and what she characterized as the Pentagon’s silence on plans for space-based weapons, fuel suspicion that the real purpose of the

experiments is to test anti-satellite capabilities, she said.

Recent examples of such experiments

include the Front-end Robotics Enabling Near-term Demonstration (FREND), which is being developed by the Naval Research Laboratory in Washington with funding from the Defense Advanced Research Projects Agency. FREND is intended



the ability of what the laboratory describes

as a

space tow truck

to reposition or de-orbit satellites, or dispose of large pieces of space debris. In an Aug. 28 press release, the laboratory said

it recently completed algorithms

that will be key to enabling the autonomous grappling operations envisioned for the FREND concept.

“A simulation of a realistic geostationary communications satellite with no visual aids or docking aids was grappled reliably in realistic on-orbit lighting conditions,”

the news release said.” The demonstration was completed under full autonomy with no human-in-the-loop assistance.”

Dick Thompson, a spokesman for the Naval Research Laboratory, and Jan Walker, a spokeswoman for the Defense Advanced Research Projects Agency, did not respond to requests for comment by press time.

The FREND system could be ready for an orbital demonstration following testing to be conducted in the laboratory next year, according to the news release.

Grappling that has been conducted in the laboratory thus far has featured a “research grade” robotic arm controlled by software that enabled autonomous grapples, according to the news release.

The Pentagon’s most recently conducted, known

autonomous rendezvous demonstration was the

Orbital Express in-orbit servicing experiment

, which was launched in March. The mission consisted of two satellites that separated from and then closed with one another on orbit and exchanged fuel and hardware. The satellites were de-orbited in July.

To be serviced on orbit in the manner demonstrated by Orbital Express, satellites would have to be specially designed, which means that for the Pentagon’s current fleet of spacecraft, and those well along in development, this is not an option.

The FREND concept gets around the compatibility

issue with robotic arms that can grab onto features that are found on just about any satellite, such as the holes for the bolts that connect spacecraft to their launch vehicles, the news release said. Robotics specialist Alliance Space Systems of Pasadena, Calif., is building a pair of prototype arms that are slated for delivery to the lab in July 2008, according to the release.

Alliance has built similar robotic hardware for NASA Mars spacecraft, according to the company’s Web site.

points out that that a spacecraft capable of grappling others regardless of their design has inherent potential as an anti-satellite weapon.