Apollo 13: Bring Them Home — an interactive Space Academy mission

Apollo 13 launched from Kennedy Space Center on April 11, 1970, the third mission NASA intended to land astronauts on the Moon. Commander James Lovell, Command Module Pilot Jack Swigert, and Lunar Module Pilot Fred Haise were roughly 205,000 miles from Earth and coasting toward the Moon when the mission changed forever. At about 55 hours and 55 minutes of mission elapsed time — around 9:08 p.m. CST on April 13 — Swigert flipped a switch to routinely stir the cryogenic oxygen tanks in the Service Module. Damaged wiring inside oxygen tank No. 2 sparked, the tank ruptured, and a bang shuddered through the spacecraft. Swigert first radioed, 'Okay, Houston, we've had a problem here,' and Lovell repeated the words that entered history: 'Houston, we've had a problem.' A whole panel of the Service Module had been blown away, and the ship was venting oxygen into space.

With oxygen tank No. 2 gone and tank No. 1 bleeding down, the fuel cells that generated the Command Module's electricity, water, and air were dying. The Moon landing was instantly abandoned; the only mission now was survival. Flight controllers in Houston, working under flight directors including Gene Kranz and his teams, had the crew power down the crippled Command Module Odyssey and move into the Lunar Module Aquarius — a craft designed to sustain two men for about 45 hours, now the lifeboat for three men facing a roughly 90-hour trip home. Because Apollo 13 was not on a free-return trajectory, engineers fired the Lunar Module's descent engine to swing the ship around the far side of the Moon and back toward Earth, deliberately avoiding the suspect Service Module engine. When rising carbon dioxide threatened the cabin, ground teams devised the famous 'mailbox' — an improvised adapter of canisters, plastic bags, a hose, cardboard, and tape that let the square Command Module scrubbers work in the round Lunar Module system.

A second critical burn about two hours past the Moon (the 'PC+2' burn), flown by hand with Earth held in the window because the guidance platform was powered down to save the re-entry batteries, sped the ship up by roughly 580 miles per hour, cut about ten hours off the return, and moved splashdown into the Pacific. In the final hours, backup crew member Ken Mattingly and the controllers worked out an unprecedented cold-start procedure to wake the freezing, condensation-soaked Command Module on its limited batteries — and nothing shorted. After a longer-than-normal communications blackout during re-entry, three parachutes bloomed over the South Pacific, and Apollo 13 splashed down safely near the recovery ship USS Iwo Jima on April 17, 1970, after 5 days, 22 hours, and 54 minutes in space. All three astronauts survived. Though it never reached the lunar surface, Apollo 13 became known as the 'successful failure' — an enduring testament to improvisation, teamwork, and the discipline of the people who brought a broken ship home from a quarter million miles away.