Like Apollo 4, this flight was long delayed, due in part to setbacks in development of the LM, manufactured by Grumman Aircraft.

The original Saturn IB rocket that was to take the first LM (LM-1) to space was taken down during the delays and replaced with the one that would have launched Apollo 1 if the spacecraft fire that killed three astronauts had not occurred.

LM-1 arrived at the Kennedy Space Center in June 1967; the following months were occupied in testing and placing the LM atop the Saturn IB.

After final delays due to equipment trouble, the countdown began on January 21, 1968, and the space vehicle was launched the following day.

Apollo Program Manager Major General Samuel C. Phillips had originally hoped that the uncrewed test flight of LM-1, the first lunar module, would launch in April 1967.

Anticipating six months for checkout and testing of the vehicle, NASA asked Grumman to have LM-1 delivered to Kennedy Space Center in Florida by September 1966, but due to difficulties in manufacturing LM-1, delivery was repeatedly delayed.

[10] On June 23, LM-1 arrived at Cape Kennedy on board Aero Spacelines' Super Guppy; the stages were mated to each other four days later.

[9][11] A 400-person team under John J. Williams, a veteran of launch operations for both Mercury and Gemini, checked to see that LM-1 met specifications, after which they supervised Grumman technicians, who tested and modified the vehicle.

[9] As of September 6, 1967, Apollo 5 was running about 39 days behind the plan established on July 18, but all known issues were being dealt with, with the exception of some leaks from the propulsion system.

[20] The space vehicle for this mission was 55 meters (180 ft) tall but had a stubby appearance since it had neither a CSM nor a launch escape system.

[26] On January 22, 1968, Apollo 5 lifted off from Launch Complex 37B at Cape Kennedy Air Force Station[23] at 17:48:08 Eastern Standard Time (22:48:08 UTC).

[1][b] The nose cone was jettisoned, and after a coast of 43 minutes 52 seconds, the LM separated from its adapter, in a 90-by-120-nautical-mile (167 by 222 km) orbit.

[1] After two orbits, the first planned 39-second descent-engine burn was started, but this was aborted after only four seconds by the Apollo Guidance Computer, which detected that the spacecraft was not going as fast as expected.

[28] The ascent stage spun out of control eight hours into the mission, after completion of the engine burns, due to a problem with the guidance system.

"[23] Despite the trouble during the descent-engine burn, NASA deemed the mission a success in demonstrating the LM systems, and a second uncrewed flight test using LM-2 was cancelled.