(WHNT) — The Apollo 13 mission launched 53 years ago today, but it wasn’t long before the crew phoned Houston to say “We’ve had a problem.”

The Apollo 13 mission was the seventh crewed mission apart of the Apollo space program and was supposed to be the third to land on the moon.

The spacecraft was set to land on the Fra Mauro area on the side of the Earth’s moon. But, an explosion in one of the oxygen tanks just over 55 hours after launch caused them to circle the moon without landing.

The original crew included:

  • James A. Lovell Jr., Commander
  • Fred W. Haise Jr., Lunar Module Pilot
  • John L. “Jack” Swigert Jr., Command Module Pilot

But unforeseen problems came for the mission even before the explosion.

Just days before Apollo 13 was set to launch, a backup lunar module pilot Charles Duke unintentionally exposed the crew to German measles. Mattingly, the Command Module Pilot for the mission, had no immunity to measles. He was replaced by backup command module pilot, John “Jack” Swigert.

Also prior to the launch, ground testing had shown it was possible a “poorly insulated supercritical helium tank in the lunar module.” The flight plan had to be modified to account for this tank.

Despite these setbacks, the launch was still on for April 11, 1970. The spacecraft launched from Cape Kennedy, Florida launchpad 39A at 1:13 p.m. CST.

NASA’s recap of the launch says that apart from a few minor surprises, the first two days of the Apollo 13 mission had looked like the “smoothest flight of the program.” Crew members on the ground were discussing how it was going so well that they were “bored to tears.”

At 55 hours and 46 minutes into the mission, the crew finished a 49-minute broadcast showing the world how comfortably they were living and working.

Just nine minutes later, service module oxygen tank no. 2 blew up after a routine stir ignited a damaged wire inside, causing oxygen tank no. 1 to fail as well. The spacecraft was about 200,000 miles from Earth and the command module lost its normal supply of electricity, water, and light.

Swigert heard a bang, felt a vibration, and saw the warning light. “Houston, we’ve had a problem,” Swigert famously said.

Two of three fuel cells were also lost, with warning signs indicating the trouble. Moments later, Lovell noticed something venting out of the spacecraft while looking out the left-hand window.

“We are venting something out into the… into space,” Lovell reported to Houston. “It’s a gas of some sort.”

Pressure in the oxygen tanks continued to fall following the explosion, and fear they would lose all oxygen and the last fuel cell was rising. Ground controllers had to write and test new procedures quickly before passing them up to the crew in space, so they could return home safely.

Running low on power and water and dealing with a wet, chilly environment, the crew moved to the lunar module and worked with the mission controllers to create a solution. Several hours later, the spacecraft was realigned and after rounding the far side of the moon, a long burn was completed to speed up the return home.

The crew returned to the command module and splashed down in the Pacific Ocean on April 17.

The Apollo 13 mission may not have landed on the moon as it was intended to, but it was classified as a “successful failure” because of the knowledge gained from having to rescue the crew.