Is the Pentagon's robotic satellite refueler lost in space? Apparently not, according to the Defense Advanced Research Projects Agency, which says its Autonomous Space Transport Robotic Orbitor and Next Generation Satellite are safe and sound. But the two spacecraft making up the Orbital Express demonstration program suffered a setback that program officials are scrambling to correct after the ASTRO vehicle traveled farther away from the NextSat vehicle than planned last Friday. The spacecraft were supposed to separate to a distance of 10 meters and then remate, but a "serious sensor flight computer anomaly" put the ASTRO into an abort trajectory that sent it 120 meters from NextSat.
But it's not time to get too gloomy about the program. Just one week earlier, the spacecraft successfully separated to a distance of 7 meters and remated.
Darpa is attempting a three month demonstration designed to prove that spacecraft can be refueled and upgraded on orbit, extending their lifecycle and reducing the costs associated with high-risk satellite launches.
Here's Darpa's May 15 explanation of what happened:
During Scenario 3-1 execution on the evening of May 11, Orbital Express encountered a serious sensor flight computer anomaly on the ASTRO while stationkeeping at 10 meters separation distance from the NextSat. Onboard fault protection reacted immediately, placing the ASTRO into an abort trajectory which carried it to a hold-point 120 meters from the NextSat. The Orbital Express team has spent the past several days recovering from this fault and from problems associated with loss of relative navigation at the longer-than-anticipated separation distances for this scenario. The ASTRO has since coasted at distances of up to several kilometers from the NextSat. Both vehicles are safe. The ASTRO powered up its redundant sensor flight computer and is processing sensor data nominally. The team is in the process of developing a recovery scenario for ingress and remate, and hopes to execute this ingress in the next several days.
--Catherine MacRae Hockmuth