The prototype satellite NextSat poses with the Earth as a backdrop in this orbital view taken by its robotic refueling partner, the ASTRO spacecraft.

NextSat and the unseen ASTRO satellites form the Orbital Express mission, a three-month spaceflight by the Defense Advanced Research Project Agency that launched into orbit on March 8, 2007. The $300 million spacecraft duo are designed to demonstrate technology for autonomous satellite refueling, docking and undocking, as well as component installation, replacement or repair.

ASTRO, short for Autonomous Space Transport Robotic Operations, and NextSat have already autonomously transferred fuel between themselves as they orbit high above the Earth. Mission controllers also stitched together a short video animation from more than 1,600 images taken by a camera on ASTRO’s robotic arm.

Earlier this week, a mating ring securing the two spacecraft together jettisoned, allowing ASTRO to undock from NextSat, and then reattach itself to the target satellite. This view was taken during that undocking-redocking procedure on April 17.

• VIDEO: The View for Orbital Express
• Prototype Satellites Demonstrate In-Orbit Refueling
• VIDEO: Orbital Express Mission Overview
• Atlas 5 Rocket Launches Six Military Research Satellites into Orbit
• Orbital Express: Prototype Satellites Primed for In-Flight Service
• All About Satellites

-- Tariq Malik

Credit: DARPA.