Sensor Flight Computer Anomaly

Launched in March, the Orbital Express mission has been progressing nicely. We blogged this cool space video last month, and I like the possibilities of this mission: on-orbit servicing of satellites. Potentially saving millions for all dependent on commercial space systems.

Then we read this from the DARPA Public Affairs Office, via

15 May 2007 Update from Jan Walker, DARPA PAO:

"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."

Editor’s 14 May 2007 note: At this point ASTRO and NextSat should be a few meters apart. Some observers are suggesting that they are kilometers apart. No word from DARPA.

OE observed with Nextsat, SeeSat-L

"… NEXTSAT appeared to trail by about 0.5 deg, when at a range of about 600 km, which indicates a distance of about 5 km."

The account by New Scientist was more alarming than that:

The US military’s experimental satellite mission, Orbital Express, may be in peril. The lead spacecraft ASTRO has drifted several kilometres away from where it should be.

No updates from Boeing yet, but they’ve got a great team of people working on this mission. I’m sure they’ll recover from this without a scratch.