The US Defense Advanced Research Projects Agency (DARPA) Orbital Express Space Operations Architecture’s ASTRO prototype satellite servicing vehicle suffered a guidance failure after its 8 March launch.
Orbital Express’ goal is to validate the feasibility of robotic autonomous on-orbit satellite re-fuelling and electronic system improvement to support future US national security and commercial space programmes.
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The Orbital Express demonstration vehicle consists of a pair of mated satellites, ASTRO and NextSat, a next generation serviceable client satellite.
After its release from the Centaur upper stage of the Lockheed Martin Atlas V rocket that launched it into its proper orbit from Cape Canaveral, the ASTRO vehicle had what DARPA describes as a “a guidance anomaly”.
ASTRO then attempted to achieve a Sun-safe attitude, to ensure its solar arrays were pointing toward the Sun, but the guidance error prevented the system from achieving the right attitude.
“To correct for this problem control of the mated pair was shifted from ASTRO to NextSat and the Orbital Express team used NextSat’s guidance system to successfully point the mated stack towards the Sun,” says DARPA.
Since then NextSat has continued to control the stack while the Orbital Express team determined the root cause of the problems experienced during ASTRO’s in-orbit initialization and Sun-safe pointing.
A software fix has been uploaded to ASTRO to correct the guidance anomaly and the Orbital Express team will resume the originally planned ASTRO/NextSat checkout and mission operations early next week.
DARPA says NASA plans to use Orbital Express autonomous rendezvous and proximity operations sensors and software to reduce risk for collaborative human-robotic space operations.