Endeavour To Demo Orion Relative Navigation

HOUSTON — Endeavour’s final flight, a 14-day STS-134 mission to the International Space Station, could feature an unusual amount of activity around the orbiting science laboratory, including a re-rendezvous demonstration of the relative navigation sensors developed for the Orion spacecraft.

The mission also could include a “family portrait” of the outpost and docked spacecraft that would be taken by a Soyuz crew. The portrait was proposed for Discovery’s last mission, but the idea was eventually rejected.

Endeavour is tentatively scheduled to launch from NASA’s Kennedy Space Center on April 19 at 7:48 p.m. EDT, on the 19-year-old spacecraft’s 25th trip to orbit.

AMS

A six-member crew, led by veteran astronaut Mark Kelly, has trained to deliver the Alpha Magnetic Spectrometer, a $2 billion external astronomical observatory, and a spare parts platform.

However, NASA’s next-to-last shuttle mission also will support Storrm (Sensor Test for Orion Relative Navigation Risk Mitigation), the first flight demonstration of the relative navigation sensor package developed for the automated rendezvous and docking operations of Orion with secondary spacecraft.

The sensor package, a flash lidar and high-definition camera located close to the orbiter docking system, will shadow the Endeavour crew’s initial approach and docking. As they undock, pilot Greg Johnson will carry out the traditional “fly around” of the station before the astronauts maneuver through a co-elliptical trajectory to a point 29,000 ft. behind and below the station.

There, Kelly’s crew will initiate a second rendezvous, using NASA Mission Control-generated rendezvous solutions and onboard radar while the Storrm sensor package follows and records the approach for post-mission analysis.

The test brings the orbiter to a point 1,000 ft. below and 300 ft. behind the station before Endeavour is released for eventual return to Earth.

“It’s an outstanding way to take advantage of the spaceflight capabilities we have today, with both the shuttle and the space station, to demonstrate new technologies,” says NASA’s Gary Horlacher, STS-134 lead flight director.“This capability is being developed for Orion, but it’s very applicable to any spacecraft that will be docking — even in lunar orbit or Mars orbit,” Horlacher says. “It’s a very significant advance in technology.”

Family portrait

During Discovery’s STS-133 mission that concluded earlier this month, the Russian space agency vetoed a proposal to undock one of two Soyuz spacecraft at the station, piloted by a crew equipped with cameras to take photos of the docked orbiter surrounded by European, Japanese and Russian cargo craft.

But Russia objected to the hour-long glam shot, proposed two weeks before Discovery’s Feb. 24 liftoff, because it disrupted the initial test flght of the new Soyuz equipped with digital avionics (Aerospace DAILY, March 2).

However, discussions are under way to re-attempt the portrait during Endeavour’s stay, although Japan’s HTV-2 will be absent.

“They had a lot of work to do in a very shot period of time,” says NASA’s Derek Hassman, the lead station flight director. “We have the benefit of the work they did. My expectation is [we] will have a decision before we launch.”