The Mammoth Book of Space Exploration and Disasters

It is interesting that Skylab became overheated out in space – because Apollo 13 became unbearably cold when in trouble. Why the difference? First it should be understood that a passive body in space absorbs and radiates heat. If these are not equal the body will heat up or cool down to a stable temperature where the heat being received equals the heat loss, providing the conditions remain constant. Although there are other factors, the simplistic explanation is Skylab lost its temperature controlling thermal heat shield which was carefully designed to balance the heat absorption and losses in its planned environment. The Laboratory was also orbiting very close to Earth. As the Earth radiates roughly the same amount of heat it receives, particularly in the infrared band, Skylab was receiving heat energy from both the Sun and Earth while in daylight, so its temperature went up.

Apart from being away out in space beyond the Earth’s reflected heating influence, Apollo 13’s electrical equipment was shut down to an absolute bare minimum, so again the carefully planned temperature control for its environment was out of balance. With the lack of internal heat being generated by the spacecraft’s electronics, Apollo 13’s temperature went down.

After nearly 26 minutes into the flight the solar panels for the telescope mount were successfully set up, but when they tried to extend the two big wing-like solar panels to provide the electrical power for the workshop just before Carnarvon, nothing seemed to happen. When Skylab came up over the horizon, Carnarvon found that instead of 12,400 watts of power there was a paltry 25 watts! As these panels supplied 60% of the power to run the laboratory, added to temperatures going up by the hour, and there was also a gyro malfunction, Skylab was in deep trouble – and the mission had just begun!

EGIL, the flight controller in Houston for the spacecraft electrical and environmental systems at the launch, was John Aaron:

“Right after the spacecraft got into orbit the rules called for me to start powering it up and turn on the heaters to warm up the inside. I told Flight I didn’t want to do that because I realised something was really wrong. The power system wasn’t activating right and the temperatures were going up instead of down in the workshop.”

For ten days engineers worked to save the project before the Skylab 2 mission was launched on 25 May to fix the problems by means of EVA. Lindsay:

“Tally Ho! The Skylab. We got her in daylight at 1.5 miles, 29 feet per second.” It was 8 hours after another perfect Saturn 1B launch at 9 am EST, and Conrad could see the crippled laboratory above the bright Earth below. They did a fly-around Skylab and sent video pictures of the damage back to Houston, confirming that the micrometeorite shield was gone and the single remaining solar panel was stuck down by what looked like a strap of aluminium.

They parked the Command Module by soft docking it to the laboratory, and while the ground crews studied their television pictures of the damage, the astronauts tucked into their first meal.

“Dinner’s going pretty good,” reported Conrad, “except that Paul found another one of those tree trunks in the asparagus. I had stewed tomatoes for lunch. It turned out even as goopy as they are, they were real simple to handle, and the same way with the turkey and gravy.”

After discussions with the ground they decided to do an EVA to try and prise the solar panel loose. Working from the Command Module hatch they tried to free the solar panel beam from the aluminium strap holding it down by cutting it.

Kerwin recalls, “Weitz was hanging out the side door with a shepherd’s crook in his hand – a ten foot pole with a hook in the end – trying to stick it under the opening in the solar panel to pry it up, while I had my arms around his legs to hold him in the Command Module. Pete was flying the spacecraft and every time Weitz would pull on the shepherd’s crook the two spacecraft would move towards each other and the jets would fire on the Skylab workshop and the jets would fire on the Command and Service Module and Pete would have to haul back on the stick to keep them from colliding – it was pretty spectacular.”

Weitz explains, “I tried to pry the beam up but it didn’t work because the aluminium strap was too firmly fixed. We had another fitting on the end of the pole which was a branch cutter. This thing is wrapped around your leg and comes up over your ankle to your knee on the inside and you have these scissors held parallel to your leg. These cutters didn’t work – they just weren’t beefy enough and I couldn’t get enough purchase on it to cut through the strap, so we had to give up.”