Digital Sprocket

If the VSE (Vision for Space Exploration) is to become a reality, then engineers must develop several critical path technologies. These include autonomous rendezvous and docking, and robotic assembly of space structures. NASA’s Exploration Systems Directorate is not the only organization interested in these technologies. DARPA, the military’s high-risk, high-reward research arm is working to develop the same capabilities.

At this moment, DARPA’s Orbital Express mission is testing out these technologies on orbit. Launched on March 8, the mission consists of two purpose built vehicles: ASTRO, and NextSat. The two spacecraft were boosted into space together on an Atlas V and are scheduled to separate, and then rendezvous and re-dock. Before separation, they have some impressive mission goals. ASTRO carries an extra supply of hydrazine, and will demonstrate refueling techniques by transferring the liquid to NextSat. ASTRO is also equipped with a robotic arm, resembling the little brother of that on the Shuttle and the ISS. The arm will replace electronics components on NextSat with spares carried on ASTRO. If all goes well, ASTRO will demonstrate rendezvous, docking, refueling, assembly, and repair capabilities.

All of these are on NASA’s wish list, if for different reasons than those of the Defense Department. In fact, NASA engineers are heavily involved in Orbital Express, and supplied software and sensors to the program. Although DARPA sees vital national security uses for these technologies, they also envision spawning a military/civilian space infrastructure around in-space servicing of satellites and manned facilities.

Of course, success is not guaranteed. DARPA’s first attempt at autonomous rendezvous and docking failed spectacularly two years ago when DART bumped into it’s docking target and sent it into a new orbital path. Perhaps that is why they are testing out the refueling and repair systems before undocking and performing rendezvous maneuvers. If successful, it will have applications for crew and cargo delivery to the ISS in Orion or COTS capsules. It will allow for robotic missions to upgrade future orbiting telescopes. There are many possible applications that we are only beginning to dimly perceive.