In a press conference on February 27, millionaire Dennis Tito introduced the world to Inspiration Mars. The plan for this so-called "mission for America" is to send a manned spacecraft hurtling around the far side of Mars where the planet's gravity will slingshot the astronauts back to Earth. The mission's purpose, as its name suggests, is to inspire a new generation to pursue careers in sciences, technology, engineering, and maths. More than one speaker likened this mission to Apollo 8, NASA's first flight to the Moon in December of 1968.

What struck me about this statement is the almost selective recollection of Apollo 8. The decision to send that mission to the Moon had nothing to do with inspiring Americans to pursue careers in science nor was it designed to boost national confidence that NASA could land a man on the Moon in time for Kennedy's end-of-decade deadline. It was a decision motivated by increasingly tight schedules and fear.

NASA organised its Apollo programme by systematically breaking down the manned lunar landing task into incremental goals. Each mission type was designated by a letter, and it was these lettered missions that were designed to fly sequentially; numeric designations were added later. As the sequence was in 1967, the "A" was an unmanned launch of the Command and Service Module (CSM) on a Saturn V rocket into low Earth orbit. The "B" mission would repeat the "A" mission but with an unmanned Lunar Module (LM) added to the payload. The "C" mission would be the first manned flight, a test of the CSM in Earth orbit. The "D" mission would see a manned CSM and LM tested in low Earth orbit before the "E" mission would take both spacecraft into a high elliptical orbit around the Earth as a sort of local dry run for the lunar landing. The "F" mission would take both spacecraft into lunar orbit for an in situ dry run. The "G" mission would be the first to attempt landing on the Moon.

From A to D

As Apollo missions started to fly, NASA seemed poised to stick more or less to this sequential flight plan. Apollo 4 was an "A" mission and the first launch of a Saturn V rocket in November, 1967. Apollo 5, which launched on the smaller Saturn IB rocket in January of 1968, was the "B" mission. Apollo 6, another "A" mission, was the programme's first technical failure; two of the Saturn V's second stage engines failed, putting the spacecraft in too low an orbit to fire its main engine and launch towards the Moon. In spite of the technical failure, Apollo 6 was considered a success and NASA decided to move on with manned flights. Apollo 7 was scheduled to fly in October of 1968 as the "C" mission with Apollo 8 flying the "D" mission in December.

Moon landings significant 40 years later

But when Apollo 6's Command Module splashed down on April 4, 1968, NASA was falling behind its own rigorous schedule. The Lunar Module was plagued with problems. Its ascent engine, the one designed to launch two astronauts off the lunar surface for a reunion with their third crew member orbiting in the Command Module, was stymied by fuel injector problems. The spacecraft's windows cracked during heat and stress testing. Broken wiring was common, as was stress corrosion. To top it all off, the LM was still overweight.

Putting the whole Apollo programme on hold on account of the Lunar Module was not an option in 1968. NASA simply didn't have time. The agency needed practice dealing with a crew in deep space and experience in translunar navigation, the tricky business of launching a spacecraft to a point in space where the Moon will be when the spacecraft arrives after three days of travel. Astronauts and engineers in mission control alike needed to familiarise themselves with the challenges of flying a mission in lunar orbit, communicating across a quarter of a million miles, and keeping the Apollo spacecraft healthy far from the Earth's protective magnetic field.

It was George Low, head of the Apollo Spacecraft Program Office, who came up with an elegant and daring solution: send Apollo 8 to the Moon without the troubled LM. Add ballast instead; a 9,000-kilogram LM test article would give the Saturn V the correct mass at launch for a lunar mission. The next flight, Apollo 9, would take a step backwards in the plan and fly the "D" mission in Earth orbit.

It was risky, but it was the best option. The new plan for Apollo 8 was to send the crew in their Command Module into orbit around the Moon; it was deemed senseless to go that far from home only to whip around the far side and return. The flight plan was finalised on August 19.

Inspiring, but politically-driven

Something else happened early in 1968 that helped push Apollo 8 to the Moon: the Central Intelligence Agency learned that the Soviet's Zond programme, their lunar-capable equivalent to Apollo, was making headway. The Zond 4 mission launched in March. Though unmanned, it was the first spacecraft of its family designed with a life support system. It was clear Zond would carry cosmonauts before long. It's also possible that the communications between cosmonauts Popovich and Sevastyanov in an isolated bunker and the Yevpatoriya Flight Control Center in the Ukraine via a relay on the spacecraft led NASA to believe the programme was further along than it really was. Zond's apparent progress wasn't a deciding factor in making Apollo 8 a lunar mission, but it did help justify perhaps the riskiest decision NASA has ever made.

Apollo 8's flight plan was kept secret until after Apollo 7 demonstrated that the Command Module was safe to fly in October of 1968. A little more than two months later on December 21, Frank Borman, Jim Lovell, and Bill Anders became the first men to ride a Saturn V into orbit. A burn of their main engine set them on a course for the Moon. After a three day transit, they arrived in lunar orbit on December 24. They stayed in orbit for 20 hours before beginning the three-day journey home. The crew splashed down, safely, on December 27.

There's little question that Apollo 8 turned out to be one of the more inspirational missions of the entire programme. Apollo 8 gave citizens of the world their first look at the Earth from the Moon, the famous Earthrise picture of the three-quarter Earth hanging over the lunar horizon. And it was this mission that sparked Bill Anders to observe that he and his crew had gone to explore the Moon but ended up discovering the Earth.

But we would do well to remember the circumstances surrounding Apollo 8 when calling for another like mission. This flight broke the pattern of Apollo missions out of a politically-driven necessity, a step towards achieving President Kennedy's politically charged lunar landing goal. It was spurred on by the fear, grounded on somewhat scant evidence, that the Soviet adversary might still be the first nation to send men to the Moon. Apollo 8 wasn't designed to inspire a nation or the world. Rather, its inspirational qualities were a happy consequence of a mission that was conceived of and launched in a time of war.

Amy Shira Teitel has an academic background in the history of science and now works as a freelance science writer specialising in spaceflight history. She maintains her own blog, Vintage Space, and contributes regularly to Discovery News, Scientific American, Motherboard, DVICE.

Follow her on Twitter: @astVintageSpace