Shuttle Endeavour backed away from the International Space Station late Sunday, initiating a five hour "fly around" and looping re-rendezvous maneuver that provided a successful first flight test of relative navigation sensors developed for NASA's Multi-Purpose Crew Vehicle -- the four person capsule designed to carry U. S. explorers to a variety of deep space destinations.
One of the Sensor Test for Orion Relative Navigation Risk Mitigation (STORRM) instruments, the high definition docking camera, was inactive during the demonstration because of a data recorder problem that surfaced while Endeavour was docked to the station.
However, the Hi Def recordings of the lighting conditions around the station during Endeavour's May 18 linkup should be sufficient for future development, according to Heather Hinkel, NASA's principal investigator for the STORMM test.
"We've been able to assess enough to feel the camera will be good to use on Orion," said Hinkel prior to the STORRM test.
Endeavour, with its crew of six astronauts, undocked at 11:55 p.m., EDT, ending a lengthy visit to the orbiting science laboratory that featured delivery of the $2 billion Alpha Magnetic Spectrometer and external spare parts as well as four spacewalks for external upgrades.
The International Space Station as Endeavour's crew conducts a departing "fly around."
Photo Credit/NASA TV
A ship's bell sounded as the 19-year-old orbiter began the Earth-bound leg of her 25th and final mission. Endeavour's crew is scheduled to descend to Earth on Wednesday, touching down at NASA's Kennedy Space Center at 2:35 a.m., EDT, to end a 16-day flight.
"It was a pleasure serving with you boys," NASA's Ron Garan, one of three U. S. and Russian astronaut serving as station residents, radioed the departing shuttle astronauts.
Endeavour's crew departed with a flourish.
After backing away to 400 feet, shuttle pilot Greg H. Johnson maneuvered the winged ship slowly around the orbiting science laboratory while his colleagues gathered photo documentation of the new AMS and Express Logistics Carrier-3, an external platform holding large volume spare parts for thermal control, communications and robotic systems.
"We are coming up on orbital sunrise, and we can clearly see the AMS and the ELC," announced Endeavour commander Mark Kelly. "This is really a new day for science aboard the space station."
Seventeen years in the making, the AMS is a physics particle detector developed through the efforts of experts from 16 countries to search for and characterize primordial antimatter, dark matter and other high energy particles that shape the evolution of the universe.
During the proximity operations, Endeavour astronaut Drew Feustel monitored the active STORRM hardware, the new flash LIDAR Vision Navigation Sensor developed for future MPCV orbital rendezvous and docking maneuvers and data recorders.NASA announced the transition of Orion from the cancelled Constellation Program to the Multi-Purpose Crew Vehicle project.
The VNS and Hi Def camera sensors developed by a NASA/Lockheed Martin/Ball Aerospace & Technologies team could also furnish critical range and relative velocity information to guidance systems for robotic as well as crewed planetary encounters.
Shuttle Endeavour as seen from the International Space Station during STORRM demonstration
of the flash LIDAR relative navigation sensor. The 16,500 foot separation marked the distance
the sensor acquired its station docking target. Photo Credit/NASA TV
The new flash LIDAR and Hi Def camera are expected to furnish a 16-fold improvement in docking target resolution over the shuttle's trajectory control system performance.
As Johnson’s one lap “fly around” came to an end early Monday, Kelly took over Endeavour's flight and maneuvered the spacecraft through a second larger loop that swept the shuttle crew up, over and behind the space station. At a distance of nearly 30,000 feet behind the station, Endeavour headed back and toward a position 4,500 below the station. Endeavour then advanced on the station on a gently ascending trajectory that would mimic an MPCV final docking approach.
All the while, the STORRM recorders gathered data on the performance of the flash LIDAR as it pulsed five pre-positioned reflectors on the shuttle's station-mounted docking target 30 times a second. The lighting conditions were ever changing as the background shifted from Earth to space and daylight to darkness.
The VNS sensor achieved lock at a separation of 16,500 feet.
At 4:38 a.m., EDT, and a point 950 feet below the orbital outpost, Kelly broke off the rendezvous exercise as planned.
Once the shuttle lands, the data recorded by the STORRM hardware during the Memorial Day test as well as Endeavour's initial May 18 rendezvous and docking will be flown to Lockheed Martin's new Space Operations Simulation Center in Denver.
There, experts will verify the test equipment function and integrate the data into spacecraft simulation software.