Pete Conrad and Dick Gordon flew Gemini 11 to 853 miles altitude — the highest any American had ever been, at the time.

They did it by docking with the Agena target vehicle and using the Agena’s engine to boost their orbit dramatically. From 853 miles, they could see the entire disk of the Earth and the curvature clearly — the planet as a ball, not just a horizon. Conrad described looking down at Australia and seeing the whole continent.

Gordon did two EVAs, one of which involved tying a tether between Gemini 11 and the Agena — a 100-foot tether. Then Conrad fired small thrusters to spin the combined system slowly, attempting to create artificial gravity through centrifugal force. The tether bowed outward as expected and there was a slight gravity-like effect, though not as stable or useful as hoped. The tether experiment was exploratory; nobody expected it to be a practical solution for artificial gravity.

Gordon had a hard time on his first EVA — similar to Cernan and Collins, he exhausted himself working outside the capsule. He was soaked with sweat, his heart rate was too high, and he had to cut the EVA short. His second EVA was a stand-up EVA (hatching open, standing in the capsule, not fully going outside) and went better because the workload was lower.

The pattern is clear now. Every Gemini EVA except Aldrin’s on Gemini 12 has had problems with overexertion and suit performance. Aldrin’s neutral-buoyancy training approach is the fix. But it took until the last Gemini mission to prove it conclusively.

The 853-mile altitude record is a curiosity. Not particularly useful for the Moon program, but a demonstration of what you can do with an Agena in the same orbit. Conrad and Gordon will be back: Conrad commands Apollo 12. Gordon flies with him as the CMP.