This could be big trouble, ol’ buddy. After trying to close the big payload bay doors in a test, we smell the hint of possible disaster. It’s June 30, 1982, Flight Day 4 of our STS -4 mission. Overnight, in a change of plan, we’ve conduced a 10-hr. heat soak of Columbia’s belly, with underside pointed continuously toward the sun. This was done to bake out the rainwater that soaked into the tiles during a downpour the day before launch. The fear was that on re-entry, the water would turn to steam and pop off the surfaces of the critical black tiles. That accomplished, the question then was, what were the effects on the doors, made of composite material, of the temperature extremes ? On STS-3, they had trouble closing the clamshell doors after they’d been distorted by prolonged heat/cold soaks.
So we closed the big, one at a time, in a test. . .
As we watched the port door come down, we saw it too late. It was warped and hit the aft bulkhead before we could stop it. We could see a gap at the aft seal. Damn — the door appeared bent.
If it is, if it won’t seal on reentry, we very likely will burn up. We calmly reported to Houston that the door has a “very substantial distortion.”
OK, let’s open the door and see what happens. It pops loose as if on a spring. “The back end of it really gave a big jump . . .” And that seems to straighten up the deflection in the door. We’re told to begin 10-hrs. of “barbecue mode” — a slow roll to even out the temperatures on the vehicle. Then we’ll see for sure if the door will seal.
Actually things have been going smoother on our flight than the previous three. We’ve had fewer failures and glitches — and are able to fix one. Commands initially were not reaching the Getaway Specials (GAS) suite of small experiments in canisters in the payload bay. The circuit to activate the payloads apparently suffered a broken wire. So we “hot wire” the system, using a jumper to feed commands through a ground wire.
The other major (secret) failure involves a stuck lens cap on the Air Force’s CIRRIS infrared sensor telescope. Discussions were made about trying to jar it with the Shuttle’s 50-ft. long robot arm. Or even conducting a spacewalk. No, Mission Control decided, not on a test flight.
Systems testing remains the priority, gathering engineering data on the performance of various subsystems to verify the models developed to predict how they will function. And that keeps us plenty busy. For example, take the testing of the Remote Manipulator System (RMS), as the robot arm is named, we conducted on Flight Day 3. That was a long day with hardly a break. We flexed the arm to lift a desk-size contamination monitor for a survey of the area around the payload bay, mapping the effects of outgassing from the shuttle that could affect sensitive instruments. And then we conducted, in the same vein, a survey of the contamination produced when we fire our small maneuvering jets. That took three hours of teamwork between the two of us, maneuvering the arm while firing jets and keeping careful watch of the positioning, especially when the arm was moved over Columbia’s nose. In total we operated the arm for 5 hours.
And we’ve begun operations in the middeck with the Continuous Flow Electrophoresis System that separates biological samples using an electric field. And we’re testing the livability of the Shuttle, including a new exercise treadmill. Yes, we’re damn busy.
Early on Flight Day 5, it’s time to try to close the payload bay doors again. “I propose to watch it like a hawk. The first time I see it bend upward, I’m going to stop.” And you bet our eyes are pinned on that port door, ready to back off the test. The clamshell door swing toward closed. Looking good, looking good. “Stand by . . . Mark! Closed. They closed perfectly.” Yes! We can report, “The door closed in the ready-to-latch position without hitting a thing. It worked perfect.”
And Capcom Brewster Shaw concurs. “Everything looks good. Continue with your mission.”