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“The crew needs to get operational experience for EVAs and we need to get EVA inputs for space station design — it's a perfect match," Whitsett said.
By coincidence, Ross was the last American to shut the door on space, after conducting two spacewalks on STS-61B in late November 1985.
"When I got back inside after my second EVA on 61B, I thought that was the finale … I'd never have that opportunity again," Ross said. “But through a strange twist, I'm going to do this one. You know, I smile a lot thinking about it. It is really a fantastic experience you just can never fully explain to anyone.”
A method for crew members to move up and down the 400-foot long space station truss structure has always been planned, but the original concept was akin to a large space golf cart.
"We thought it was overkill," Whitsett said. “It was like taking a bus when all you need to do is go out to the back field on your motorcycle."
Although the simplest method of movement would be a hand-over-hand pull down the truss, with no special equipment except a tether, such a method could cause excessive wear and tear on the truss and suit. Also, it would be difficult to carry cargo.
CETA may be the answer. It is a small cart that runs along a track which can be built into the Space Station Freedom truss. Astronauts would ride prone on CETA, and could pull equipment along behind them. But how to propel the cart, how much stress the various methods of movement would put on the truss and the astronaut, and how fast it can be comfortably and safely moved are questions to be studied on STS-37.
The cart will be mounted on a track in the payload bay, skirted by two handrails for half of the bay and by one rail, to be extended following deployment of the Gamma Ray Observatory (GRO), for the entire distance 46 feet. Apt and Ross will move the cart in three different fashions: lying prone, one crewman will pull himself along the track hand over hand; with the astronaut angled upward slightly, the cart will be changed to accommodate a lever that can be pumped to move it up and down the track, much like an old railroad handcar; and, also with the crewman at about a 45-degree angle, the cart will be propelled by hand-pushed pedals similar to a bicycle - the pedals will generate electricity to drive the cart.
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