Endeavour Re-Rendezvous for STORRM Begins

At 1:36 a.m. EDT, space shuttle Endeavour’s engines were fired a second time, the first maneuver to bring Endeavour back toward the station for the Sensor Test for Orion Relative-navigation Risk Mitigation, or STORRM. Commander Mark Kelly is piloting Endeavour for the re-rendezvous. Endeavour will approach within about 600 feet of the station.

STORRM is examining sensor technologies that could make it easier for future space vehicles to dock to the International Space Station. STORRM’s visual navigation system will provide an image of the space station. The visual navigation system is an eye-safe flash lidar system that operates very much like a stop sign reflecting headlights. On the docking port of the space station are specialized retro-reflectors — which are made from material similar to that used on stop signs — that bounce light back with minimal scattering. The lidar targets the retro-reflectors to calculate the range and line-of-sight angle measurements that the system then provides to the relative navigation software.

Nearly five hours after undocking, Endeavour’s engines will fire again to depart the station’s vicinity. The shuttle will begin to increase its distance behind the station with each trip around Earth.