SPHERES Flight Experiments
Flight testing, evaluating both testbed and control algorithm performance, has been conducted on board NASA's KC-135 "Weightless Wonder" and will be continued on board the International Space Station in 2003.
Tests on the KC-135 have confirmed the functionality of SPHERES as a formation flight testing platform with dynamics representative of true spacecraft. Tests on the International Space Station will allow long duration testing of more complex control algorithms. Flight experiments provide dynamics that will allow control designers to see exactly how their algorithms will perform in the space environment.
KC-135 Flight Experiments
The Reduced Gravity Program at NASA's Johnson Space Center provides the unique "weightless" or "zero-g" environment of space flight using a specially modified KC-135A. The KC flies parabolic arcs to produce weightless periods of 20 to 25 seconds. This capability is ideal for the development and verification of space hardware, experiments, crew training and basic research.
Flight tests of the SPHERES testbed onboard NASA's KC-135 accomplished two objectives: (1) establish the functionality of testbed systems and subsystems and (2) perform limited formation flight experiments. Flight experiments were conducted over two separate weeks in early 2000, once in mid-February and again in late March. The time between flights was used to refine operations protocols, improve testbed systems, and develop more complicated experiments using lessons learned from the first week of flights.
International Space Station Experiments
Two SPHERES satellites have been launched to the International Space Station. The third satellite is scheduled for launch on Flight 12A.1 on December 15, 2006.