After Apollo 15 reached lunar orbit, and his crewmates departed to land on the Moon, Worden spent three days alone in the CM, becoming in the process the individual who traveled the farthest from any other human being, a distinction he still holds.

During Apollo 15's return flight to Earth, Worden performed an extravehicular activity (EVA), or spacewalk, to retrieve film cassettes from cameras on the exterior of the spacecraft.

"[8] Worden came to like the demanding life at West Point, especially once he passed the initial stages of his military education and was given greater responsibility within the Corps of Cadets.

[13] Worden received primary flight training at Moore Air Force Base, Texas, where he learned to fly on Beechcraft T-34 trainer aircraft, coming to love piloting.

[1][15] Worden first post-training assignment was with the 95th Fighter Interceptor Squadron at Andrews Air Force Base, near Washington, D.C., where he flew F-86Ds, and later, F-102 Delta Daggers.

[1] Seeking both to advance his career and to benefit the Air Force, Worden in 1961 asked to be sent to study aerospace engineering at the University of Michigan.

He then served as an instructor at the Aerospace Research Pilot School (ARPS), to which he was ordered at the specific request of its commandant, Colonel Chuck Yeager, and from which he graduated in September 1965.

[22] Worden, aged 34 when selected, was one of the 19 candidates chosen by NASA in April 1966, together with his ARPS classmates Stuart Roosa and Charles Duke; four others were previous graduates.

Budget cuts and the diversion of funds to other programs meant there would be relatively few flights, and Worden perceived some resentment at the new intake from more senior astronauts as the competition for spots on Apollo missions intensified.

[28] Worden was at North American Aviation's plant in Downey, California, where the Block II command module was being built, on January 27, 1967, when he received an urgent phone call from Slayton, informing him that all three Apollo 1 astronauts had been killed in a fire at the launch pad, where a test was under way.

After the pause, he remained on the support crew for the second Apollo mission, which was to include testing of the CM and Lunar Module (LM) in Earth orbit.

[37] As Apollo 12's backup command module pilot, Worden forged a close, lifelong friendship with the prime crew's CMP, Dick Gordon, with whom he trained.

"[38] Gordon and Worden learned navigational techniques for space so that if communications with Mission Control failed, the CMP could bring the craft home.

[39] Worden remembered that the Apollo 12 prime crew, led by Pete Conrad, had a close bond and drove matching black and gold Chevrolet Corvettes at Kennedy Space Center (KSC).

[44] He also accompanied his crewmates on geology training which took them to places where they walked over terrain resembling the Moon's, including sites in Hawaii, Mexico, and Iceland.

[45] When he was not busy with that or other training, Worden spent much of his time at North American Rockwell's facilities at Downey, supervising the construction and testing of Apollo 15's command and service module (CSM).

When the two craft failed to separate to allow Falcon and its crew to prepare for the Moon landing, Worden went into the docking tunnel and reconnected a loose umbilical, fixing the problem.

He concluded it was naive to believe Earth had the only life in the universe, and he wondered if space exploration was part of humanity's survival instinct to avoid being trapped in a single solar system.

"[61] As Falcon took off from the Moon, Worden played a recording of the Air Force Song ("Off we go, into the wild blue yonder"), intending it to be heard only in Mission Control; somewhat to his chagrin, it was relayed to the LM, to the annoyance of Scott.

In retrieving the film cassettes from the panoramic and mapping cameras, Worden performed the first deep-space EVA,[65][66] and reported his personal observations of the general condition of equipment housed there.

[1] The crew had, before the mission, agreed with an acquaintance named Horst Eiermann, who was working on behalf of a West German stamp dealer, Hermann Sieger, to carry 100 postal covers to the Moon in exchange for approximately $7,000 to each astronaut.

These were carried aboard Endeavour prior to launch by Scott in his spacesuit's pocket, were transferred into Falcon and spent three days on the lunar surface inside the lander.

NASA rules required that personal items carried aboard Apollo flights be manifested for weight and other reasons and approved by Slayton; this was not done.

[68] The astronauts stated their intent had been to set up trust funds for their children,[69] and that they intended that the covers not be sold or otherwise publicized until the Apollo program was over and they had left NASA and the Air Force.

Slayton, knowing Worden was a stamp collector, became suspicious that he had arranged both deals, and this led to repeated phone calls asking for details.

[85] He found an ally in Associate Administrator for Manned Space Flight Dale D. Myers, who helped Worden get a position at the Ames Research Center in California.

[1][67] In his first book of memoirs, Worden took responsibility for making "a decision that fucked up my life completely, utterly, and irreversibly", but felt Scott did not take enough of the blame on himself.

[88] Apollo 10 commander Thomas P. Stafford wrote an epilogue to Worden's first book and stated, "Al should not have his efforts degraded by the decades-old, short-lived publicity surrounding some postal covers carried on board.

"[8] The Apollo 15 astronauts had been required to turn in, and NASA had retained, 298 of the postal covers carried aboard by Scott, as well as 61 more envelopes from the deal with Herrick; they were transferred to the National Archives in August 1973.

[95] In 2011, Worden's autobiography, Falling to Earth: An Apollo 15 Astronaut's Journey to the Moon made the top 12 of the Los Angeles Times Bestseller list.