The Orbital Express flight demonstration was established by the Defense Advanced Research Projects Agency
(DARPA) to develop and validate key technologies required for
cost-effective servicing of next-generation satellites. A
contractor team led by Boeing Advanced Network and Space Systems built two mated spacecraft launched atop an
Atlas V rocket from Cape Canaveral, Florida, on March 8, 2007. The low earth orbit test flight demonstrated on orbit
transfer of hydrazine propellant, transfer of a spare battery between spacecraft and the ability to replace a spacecraft
computer on orbit. It also demonstrated autonomous rendezvous and capture (AR&C) using advanced sensor, guidance,
and relative navigation hardware and software.
This paper summarizes the results of the on-orbit performance testing of the ARCSS (Autonomous Rendezvous and
Capture Sensor System). ARCSS uses onboard visible, infrared and laser rangefinder sensors to provide real time data
and imagery to the onboard sensor computer. The Boeing-developed Vis-STAR software executing on the sensor
computer uses the ARCSS data to provide precision real-time client bearing, range and attitude as needed, from long
range to soft capture. The paper summarizes the ARCSS and Vis-STAR on orbit performance.
The Orbital Express ASTRO spacecraft carried multiple independent sensor systems for estimating relative state in
autonomous vehicle proximity operations. The on-orbit performance of pose-estimation imaging and dedicated-target
navigation solution methods are compared, for ranges between 150 meters and spacecraft capture. Variations between
performance expectations from pre-flight ground tests and actual
on-orbit performance are discussed. Analysis results
indicate the sources of solution variations.
The Orbital Express Autonomous Rendezvous and Capture Sensor System (ARCSS) ALONG WITH ITS Vision-based
Software for Track, Attitude and Ranging (Vis-STAR) provided relative target position and attitude measurements for
guidance and relative navigation during autonomous vehicle proximity operations. The use of computer and physical
models during simulation, ground testing and verification of ARCSS imaging camera and software performance prior to
and during on-orbit operations is discussed.