WASHINGTON
- The Pentagon decommissioned its experimental Orbital Express satellites this
week, bringing the on-orbit satellite-servicing and robotics demonstration to
an irreversible end.
The two spacecraft
that comprise Orbital
Express - the Boeing-built Autonomous Space Transport Robotic Operations
(ASTRO) servicing spacecraft and the Ball Aerospace & Technologies-built
NextSat - were launched
together in early March on an Atlas 5 rocket. The in-orbit satellite
servicing experiment was sponsored by the U.S. Defense Advanced Research
Projects Agency, or DARPA.
Over the
last four and a half months, ASTRO has demonstrated its ability to approach
NextSat with limited interaction from the ground, grapple
the spacecraft with its robot arm and transfer fuel and hardware.
According
to an update posted Sunday on DARPA's Web site, the two satellites were
decommissioned after successfully completing one last maneuver that
demonstrated ASTRO's ability to find and home in on NextSat from long range
with an assist from the U.S. Space Surveillance Network. ASTRO then switched
over to on-board sensors to complete the rendezvous.
The
decommissioning was to have begun July 5, but the Pentagon extended the
mission two weeks to allow the team to attempt the long-range rendezvous
maneuver. The final demonstration entailed putting enough distance between the
satellites that ASTRO's sensor suite lost track of NextSat, and thus required
input from the ground-based Space Surveillance Network to locate the target
satellite and close in.
The
maneuver was initiated July 16 and completed over the next few days. By early
July 21, Orbital Express flight controllers confirmed that they had
successfully repositioned NextSat's solar arrays away from the sun and turned
off the spacecraft's on-board computer. Flight controllers confirmed the
following day that ASTRO, too, had been successfully decommissioned, a process
that in addition to turning off the computer entailed dumping the satellite's
remaining onboard fuel.
"The
DARPA Orbital Express program met all of its mission success criteria,"
the agency said. "The end-of-life maneuver demonstrated a capability for
long-range rendezvous and track."
advertisement
