Apollo 13 launches toward Moon carrying astronauts Lovell, Swigert, and Haise

On April 11, 1970, at 13:13 CST (18:13 UTC), Saturn V rocket SA-508 lifted off from Launch Complex 39A at Kennedy Space Center, carrying Apollo 13 on America's third targeted lunar landing mission. The flight was commanded by veteran astronaut James A. Lovell Jr., accompanied by Lunar Module Pilot Fred W. Haise Jr. and Command Module Pilot John L. "Jack" Swigert Jr. Just three days prior to launch, Swigert had been moved up from the backup crew to replace prime Command Module Pilot Thomas "Ken" Mattingly, after Mattingly was exposed to rubella (German measles) by backup Lunar Module Pilot Charles Duke.

During the powered ascent into Earth orbit, the mission encountered an early anomaly when the center J-2 engine of the S-II second stage shut down over two minutes ahead of schedule due to severe pogo oscillations. To compensate, the flight computer burned the remaining four outer engines for an additional 34 seconds, followed by an extended burn of the S-IVB third stage. This burn successfully inserted Apollo 13 into a temporary Earth parking orbit. After two orbits, the S-IVB reignited for Trans-Lunar Injection (TLI), placing the spacecraft Odyssey (Command and Service Module) and Aquarius (Lunar Module) onto a precise trajectory toward the Fra Mauro highlands of the Moon.

By 1970, public interest in the Apollo program had declined significantly following the historical success of Apollo 11 and Apollo 12. Major television networks declined to broadcast the crew's live broadcasts from space during the early trans-lunar flight. Despite the routine appearance of the early mission phase, technical oversights and pre-flight damage to an oxygen tank inside Service Module 2 were already setting the stage for one of the most perilous emergencies in the history of human exploration.

Why it matters

The launch of Apollo 13 marked NASA's transition from demonstrating basic lunar landing capabilities to executing sophisticated scientific exploration of the lunar highlands. It demonstrated NASA's capability to execute rapid crew swaps under tight medical quarantine constraints when Jack Swigert replaced Ken Mattingly 72 hours before liftoff. The flight also showcased the dynamic flight control capabilities of the Saturn V guidance system, which seamlessly compensated for an unexpected in-flight engine failure during launch.

Interesting fact

Command Module Pilot Jack Swigert realized shortly after launch that he had forgotten to file his federal income tax return before liftoff, prompting a lighthearted radio exchange where Mission Control assured him he could apply for an extension.