In addition to the fixed-base lunar module simulators in Houston and at the Cape, astronauts also practiced at Langley Research Center on the suspended lunar landing trainer which was equipped with realistic surface views and lighting.
As the lunar module approached, Young saw it through his sextant at a distance of 259 kilometers. Stafford and Cernan got a radar lock on the command module shortly after the insertion burn and watched with interest as the instrument measured the dwindling gap between the vehicles and demonstrated the theories of orbital mechanics in actual practice. Cernan especially liked the steady communications that kept both crews aware of what was happening.
After a shaky but successful S-IVB burn Apollo 10 was on the way to the Moon. Now the first order of business was for John Young to move to the command module pilot seat.
On May 18th 1969, a king, some congressmen, other distinguished guests, and a hundred thousand other watchers waited at scattered vantage points around the Cape area. At 49 minutes past noon, Rocco Petrone’s launch team sent Apollo 10 on its way to the United States’s second manned rendezvous with the moon.