The Mammoth Book of Space Exploration and Disasters

The crew spent almost two days, while the two spacecraft were still linked, checking out the LM’s many redundant systems and making sure the thrusters were in working order. Then Rusty and Jim crossed over to the lander once more and connected both their portable life support system (PLSS-pronounced “pliss”) backpacks and the LM’s oxygen hoses to their suits, before depressurizing their spacecraft, Jim McDivitt opened up the waist-high forward door – which took a lot of muscle – and Rusty crawled out onto the porch on the edge of the descent stage. From that porch he could see almost a quarter of Earth’s blue-and-white surface – quite a view.

The crew now had three radio call signs: Scott in Spider, Jim in Gumdrop, and Schweickart, the EVA man, now known as “Red Rover.” Rusty used the same golden slipper foot restraints I had used on Gemini XII. With these and the handrails on the outside of the LM, he had no trouble moving around.

The next day the crew put the LM through its most crucial task: fully testing the LM’s two engines and the spacecraft’s rendezvous radar, guidance computers, and docking system. Despite the playroom names they bantered with during the mission, there were real hazards involved in free-flying Spider up to 90 miles away from Gumdrop. If any of the LM’s components failed, McDivitt and Schweickart could be marooned in the LM. Spider had no heat shield, so they could not reenter Earth’s atmosphere.

In the CSM, Dave Scott flipped a switch to release the latches gripping the LM, but they hung up. It wasn’t a good start. He flipped the button back and forth – “recycling” in NASA-ese – and finally the LM broke free. Now came the test of the descent engine. Jirn McDivitt stood on the left side of the flight deck, and Rusty Schweickart occupied the similar place on the right. Ignition and the throttle-up to 10 percent were smooth. But suddenly there was a harsh chugging at 20 percent. After several loud thumps, Jim released the throttle hand grip and the noise stopped. When he opened the throttle again, the problem had gone away.

Now they were completely on their own. The spacecraft’s four dangling legs, braced by shorter angular struts, actually did make the LM look like a spider.

I was at Mission Control, standing behind the flight directors as they bent over their consoles, monitoring this critical maneuver as Gumdrop changed orbit to simulate its position during an actual lunar rendezvous. Many of these maneuvers were near repeats of the rendezvous exercises I’d helped develop during Gemini. Next, Jim and Rusty “staged,” breaking the Spider into two separate sections. Now the part of the spacecraft they were in was only the bulbous cabin of the LM ascent stage, perched atop its squat engine nozzle. When they ignited that engine, they felt the sudden sagging weight of their limbs as they left Zero G.

Approaching Gumdrop in the darkness, McDivitt fired his thrusters to maneuver, “illuminating the LM cabin like the Fourth of July.” Dave Scott watched the fireworks, carefully matching what he saw with the radar data on his computer display. The final approach and docking went smoothly as Spider and Gumdrop were joined again, and the two men in the LM had completed their most critical maneuver. The lunar module, which had been the program’s bottleneck for years, had just performed flawlessly in space.

Apollo 10: the full-scale rehearsal

Apollo 10 was a full-scale rehearsal of the moon landing expedition, flown by Tom Stafford, Gene Cernan and John Young. They made two orbits of the moon and flew the LEM less than 50,000 feet above the surface.

In January 1969, the Soviets still needed to test their re-entry module before they were ready for a circumlunar fly-by. On 14 January Soyuz 4 and Soyuz 5 made a rendezvous which included an EVA transfer.