Sunday, April 12, 1970

For Jim Lovell and Fred Haise, walking on the moon was looking like a ticket to anonymity.

After all, Lovell and Haise would be the fifth and sixth men to walk on the moon. How many people could name the second person to fly solo across the Atlantic -- let alone the fifth and sixth people? The world paid relatively little attention to Apollo 13 as Jim Lovell and his crew sped moonward.

But for geologists who studied the moon -- in Houston, and around the country -- Apollo 13 promised to be a scientific bonanza. Lovell and Haise's two moonwalks, scheduled for Thursday, April 16 and Friday, April 17, offered a major step forward in lunar exploration.

The promise of Fra Mauro

Already, two teams of astronauts had walked on the moon, collected rock samples and taken photos -- and in the process, had enormously increased scientists' understanding of Earth's nearest celestial neighbor.

Both of these landings, though, had taken place on the relatively flat areas of the moon, called maria (Latin for "seas," since astronomers once thought they were lunar oceans) which were relatively safe choices for the initial landing missions. The maria, formed by outpourings of lava from the lunar interior, had given scientists a window into the distant past, more than 3 billion years ago.

For Apollo 13, NASA was confident enough to send Lovell and Haise to a more rugged area. It was called the Fra Mauro highlands. The lure, for scientists, was that the highlands had formed much earlier than the lava plains. The rock samples Lovell and Haise picked up at Fra Mauro, they hoped, might reveal secret's from the moon's distant past.

The promise of Fra Mauro could only be realized by trained explorers -- and that is what Jim Lovell and Fred Haise had to become before they left Earth. Under the tutelage of some of the country's finest geologists, they came to understand that going to the moon is like being let into the rare book room of a cosmic library. The moon rocks were nothing less than pages from the earliest chapters of solar system history.

With that in mind, Lovell had chosen a motto for the Apollo 13 mission insignia: Ex Luna Scientia. In English, it meant "From the Moon, Knowledge."

The terrain in the left portion of this photograph is the Fra Mauro Formation.

Of course, Lovell and Haise were still test pilots, first and foremost. But they also understood that after two moon landings, simply getting to the lunar surface was no longer the goal of Apollo. Now, it was even more important what the astronauts did once they got there.

But getting to Fra Mauro meant departing from the usual path for a lunar mission. On Apollo 8, when Lovell had been one of the first three men to journey to the moon, he and his crewmates had followed a path called a free-return trajectory. It was aptly named: it meant that if the astronauts could not fire their main rocket engine to go into lunar orbit, the moon's gravity would bend their path onto a course for Earth.

But beginning on Apollo 12, there was a change: On the way to the moon, the astronauts briefly fired their service module's main engine to throw away their free ticket home and go onto a so-called hybrid trajectory. The hybrid trajectory was necessary in order to reach certain landing sites on the moon, including Apollo 12's target in the Ocean of Storms and Apollo 13's spot in the Fra Mauro highlands.

Abandoning the free return did entail some extra risk. But there was an underlying logic behind the change. When the engine fired to get the astronauts off the free-return, went the thinking, everyone would know it was working properly. Surely, it would work again to get them back on a path to Earth, if necessary.

At 7:53 p.m. Houston time on Sunday April 12, Lovell, Swigert and Haise were strapped into their couches inside their command module Odyssey. Under control of the on-board computer, Odyssey's main engine fired briefly to put Apollo 13 onto the hybrid trajectory.

But that was the only major task of this first full day in space. So far, this trip to the moon was relatively uneventful. At one point, capcom Joe Kerwin told the astronauts, "We're bored to tears down here."

Before long, however, those words would take on an ironic twist.