Automatic docking spacecraft will enable agency to catch up with Europe and Russia
Launch of NASA's Demonstration of Autonomous Rendezvous Technology (DART) spacecraft, delayed from November last year, is expected to take place on 15 April. DART is to rendezvous with Northrop Grumman's Multiple Paths, Beyond-Line-of-Sight Communications (MUBLCOM) satellite, which happens to have the laser reflectors required for proximity operations.
As well as rendezvous, these operations will include automated station-keeping, docking axis approach, collision avoidance and target circumnavigation. Air launched from Vandenberg, California on an Orbital Sciences Pegasus XL, the Orbital-built DART will be inserted into a circular orbit.
Dart will perform a series of orbit transfers to arrive at a point where it is following MUBLCOM. The spacecraft's AVGS video guidance sensor will detect the satellite 1km (0.6 miles) away and provide guidance to within 300m (1,000ft) of MUBLCOM.
"DART was originally for NASA's Space Launch Initiative and then for Orbital Space Plane. We will roll the lessons learned into the Lockheed Martin [Crew Exploration Vehicle] team and use the [AVGS] for DARPA's Orbital Express," says Robert Richards, Orbital Sciences' orbital launch systems vice-president.
Although Russia has had automatic rendezvous and docking capability for many years, and the European Space Agency has developed the technology for its Automated Transfer Vehicle, NASA has always used pilots for the final stages of docking.
ROB COPPINGER/COLORADO SPRINGS
Source: Flight International