Where does this come from, and can I check it?

Mission planners relied on a free return path that looped around the Moon. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a space fact?

Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Apollo 13 used the Moon as a slingshot home

Mission planners relied on a free return path that looped around the Moon After an oxygen tank exploded in April 1970, Apollo 13 could not fire its main engine normally. The crew stayed on a trajectory that swung behind the Moon and let lunar gravity curve them back towards Earth. They survived in the lunar module, rigging square canisters to fit the round carbon dioxide scrubbers. It sits in Mondo's space collection, one of 200 facts that each trace back to the reference below.

Where this comes from

NASA Science

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Space & Astronomy trivia

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Gravity assists trade planetary motion for spacecraft speedA flyby borrows a little orbital energy from the planet it passes The Apollo guidance computer held about 72 kilobytesIts core memory stored roughly 36,000 words of 15 bits each Apollo 11 landed through a cascade of computer alarms1202 and 1201 program alarms meant the guidance computer was shedding low priority work Moon dust smelled like spent gunpowderAstronauts reported the odour inside the cabin after dust came back on their suits Each Saturn V fuel pump produced 55 megawattsThe five F-1 engines burned kerosene and oxygen at about 13 tonnes a second A Moonwalking spacesuit weighed about 127 kilogramsOn the Moon it pressed down with only about a fifth of that

Tags: apollo, trajectory, rescue

Apollo 13 used the Moon as a slingshot home: the short answers

Where does this come from, and can I check it?: Mission planners relied on a free return path that looped around the Moon. The figure is taken from NASA Science, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a space fact?: Yes. It sits on the Space shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.