On the morning of August 5, 1971, we, Apollo 15, are headed home. It’s 14 hrs. since we left lunar orbit. At 7:49 a.m. in the Eastern U.S., the Moon rides 38,000 mi. in our past and the Earth 204,000 in our future, we pass the invisible line into the Earth’s gravitational influence. We’ll pick up speed from this moment on, until on August 7 when we will scorch into the atmosphere toward splashdown.
We’ve completed the longest stay in lunar orbit, working the cameras and sensors in the Scientific Instrument Module (SIM) in an open bay of the cylindrical Service Module behind us. We tell the ground, “As we go around in lunar orbit here, I can look down, I can just spend weeks and weeks, and I can pick out any number of superb sites down there . . .” Alas, after returning from our surface exploration, we only have two days in orbit.
Then on our 73rd circuit of the moon, one orbit before departing, we performed another first — the first launch of a subsatellite in lunar orbit. The tiny creature, 31 in. long, hexagonal shaped with a diameter of 14 inches, weighs 78.5 lbs. and carries three experiments probing the lunar gravity field, the magnetic fields and their interaction with the solar flux. The little fellow traveler is held in the SIM bay, spring eject along a curved groove to give it stabilizing spin. We can hear it, through Endeavour‘s structure, rifle out, the spin extending three 5-ft. sensor booms. “Tally ho!” And there it is, sides studded with solar cells glittering in the sun. “A very pretty satellite out there.”
Even after leaving lunar orbit, we’re not done making firsts. In 4 hrs, we’re about to perform yet another one. Our our Command Module Pilot, Al Worden, will perform the first walk in deep space. The SIM bay his objective; his task: Retrieve two large film cassettes from the panoramic and mapping cameras.
“The hatch is open.” It’s 11:41 a.m. EDT. Al’s wearing one of our EVA visor assemblies with the reflective gold visor. He doesn’t have an backpack like we wore on the moon — his oxygen, power and cooling are coming through a 24-ft. umbilical line — but he does wear one of our small emergency air packs that once sat on top of the backpack. Just in case. As it’d never been done before, the timeline allocates 48 min. for the spacewalk.
In the 4 hrs. since we entered the Earth’s influence, we’ve traveled 8,000 mi. closer to Earth, now 196.000 mi. away. As we’re positioned pointed back at the moon, the Earth appears behind the big engine bell of the Service Module. Al grabs one of the many handrails that will assist him and pulls himself out into the perfect blackness of deep space. Waits until Jim Irwin floats waist-high out the hatch to observe and help manage the long umbilical. “You ready, Jim?” I’ll start working my way down.”
The SIM bay stretching behind us is slightly left of the hatch, set into the curved surface of the Service Module. So Al moves across the module’s near edge and then back. He “walks” his hands on the handrails, feet straight up. He can only carry on of the large cassettes at a time. His first goal is the panorama camera.
He encounters an obstacle. “First thing, the mapping camera is all the way out.” Not unexpected — we’ve had trouble retracting it to the stowed position. It’s extended like a big wedge blocking his path. He’s able to keep hold of the handrail and float himself over the camera. He quickly passes over it without problem, swings around and anchors his feet in foot restraints in the SIM Bay. The cover comes off the pan camera easily. He tethers the cassette to himself so we’ll have no chance of losing it. It releases easily, and in a blink, Al is back at the hatch, handing the cassette over to Jim.
Capcom Karl Henize says, “Beautiful job, Al, baby. Remember there’s no hurry up there at all.”
“Roger, Karl. Come up and join us!”
Al moves out again, movements more fluid, assured. He hovers over the mass spectrometer. We’ve had trouble with it, and he tries to see if he can locate the problem. “I see nothing . . . nothing obscuring the field of view. There’s nothing in the way, Karl,” he tells Henize. The spectrometer is fully retracted but the cover isn’t closed.
The inspection only takes a moment before he moves to the mapping camera. He encounters a bit of trouble removing the cover — it takes a few tugs. “OK, Jim, we’re ready to bring the other one back.” Again his legs swing up and around from the surface of the module and he walks himself back. As he looks up, quite a sight greets him: There is the moon centered perfectly behind the Command Module and Jim Irwin halfway out the hatch. The sun, from his left, illuminates three-quarters of the moon, brushing the craters into sharp relief. “Jim, you look absolutely fantastic against the moon back there. That is really a most unbelievable, remarkable thing!”
The spacewalk has gone extremely smoothly and fast, consuming not much more than 10 min. Plenty of time. So Al makes a bit of an excuse to make a third pass to the back. “Maybe I should take another quick check back here and see if I can see anything on the mapping camera.”
In one direction, he can see the Earth and with an easy turn, takes in the moon in the opposite direction. But he doesn’t take long, later will regret he didn’t linger longer taking in the sight.
“OK, you ready, guys?” He calls, hauls himself feet first into the Command Module. The world’s first walk in deep space is over in just 16 min.
Henize congratulates him. “You sure made it look easy up there.”
Next stop, Earth, in about 53 hours.