Learning to drive on the Moon

Scott then got into his seat in preparation for powering up the rover. He read off the critical amps, voltages and temperatures to Houston, reporting no amps or voltage on battery No. 2. This turned out to be an indicator problem and the rover did indeed have both batteries functioning. Irwin took the 16 mm film camera in hand and told Scott to let him know when he was ready to drive off so he could film the rover underway. Joe Allen admonished Scott to ''Buckle up for safety.'' And then Scott moved the hand controller forward of its detent, or neutral position.

''Okay,'' Scott said to Houston, ''out of detent. We're moving''

''Extraordinary,'' Allen remarked from Houston, as he watched Scott drive the LRV slowly away. The rover was underway, and there were smiles all around in Huntsville with the LRV team, and in Mission Control in Houston, which could watch Scott drive the rover from the images being beamed back to Earth from the temporarily stationary TV camera. The euphoria was short-lived, however, as Scott reported that he had no forward steering. At Allen's direction, Scott moved the Forward Steering switch to Bus ''C.'' but to no avail. Scott was then asked to cycle the Forward Steering circuit breaker, but the astronaut reported no change as he slowly circled the LM.

''Roger, Dave,'' Allen responded. ''Press on.'' The inherent system of redundancy demanded by NASA for the LRV to ensure mission success had just proven itself, but the Boeing engineers were baffled and vexed, and immediately set to work to debug the problem.

''On the very first EVA, Scott reported the front steering did not work,'' remembered Ferenc Pavlics. ''I was in Houston at the time, and they rushed out to me and two engineers I had with me. They said, 'OK, come up with a checkout procedure to find out what is wrong.' So we did that and rushed the checklist to the CapCom. It was only minutes but by that time, they had decided to proceed with the mission with just the rear steering operational.''

Scott had driven the rover around the LM and out of TV camera range. Jim Irwin followed him with the 16 mm Data Acquisition Camera.

Allen commented that the astronauts were not visible on the TV camera, so Scott got off the rover and loped over to the camera. He moved it slightly to the left, and viewers back on Earth were greeted with a spectacular image of the majestic Swann Range in the distance, named after Gordon Swann the Principal Investigator for Apollo 15 geology. Scott then began loading the front of the rover, starting with the telecommunications equipment that included the Lunar Communications Relay Unit (LCRU), the Television Control Unit (TCU), the High-Gain Antenna with its umbrella-like appearance and distinctive gold-mesh reflector, and then the Low-Gain Antenna. Scott announced he was moving the TV camera from to the tripod to the rover, which required disconnecting it from the cable running to the LM. The image was lost briefly while Scott moved the GCTA to its position at the front of the rover and then attached the cable from the TCU to the TV camera.

Scott verified it was hooked up and that was Ed Fendell's cue to put the TV camera through its paces. Fendell was chief of the Communications System Section of the Flight Control Division and it was his responsibility to coordinate all communication to and from the Moon, including frequencies from Al Worden in the Command Module, communication patched through the LM, and communication to and from the LRV. These communications were handled by Fendell's crew while

Ed Fendell was director of communications at Mission Control in Houston. He also was responsible for operating the Ground-Commanded Television Assembly (GCTA) for Apollo 15, 16 and 17. (Ed Fendell)

Fendell himself was in charge of operating the TV camera when the rover was at rest. The High-Gain Antenna had to remain aligned with the Earth within a very narrow field, which could not be maintained while the rover was underway. The astronauts aligned the antenna by looking through a sight until the Earth filled the small window. There was a common misconception that the TV camera was controlled using a small joystick. That was definitely not the case.

"On our console," Fendell stated, "we had a panel to send commands, and under each button was a programmed command for the computer. We had a pan left, a pan right and a pan stop. Then we had pan increment right, and a pan increment left which would pan left 3 degrees and stop, or pan right 3 degrees and stop with one depression of the button. There was also an increment tilt of 3 degrees. And we had zoom in and zoom out. When I sent these commands, there was a delay of something like three seconds before the camera would respond. I had to anticipate what might happen a lot of times. The zoom was the big item because if the crew started to move, the best thing to hit first was the zoom. The zoom allowed us to keep up with them without them running out of the picture."

Fendell panned the camera to the left to take in the LM Falcon and the impressive massifs in the distance, then performed a slow continuous pan counter clockwise to take in the surrounding lurain, until it came to a stop pointing almost directly aft of the rover. Irwin came into view on the right-hand side after having stowed the core sample tubes and caps at the rear of the rover.

''And the TV scene for us is breathtaking,'' Allen exclaimed, marveling at the TV camera's resolution and image quality.

''Good,'' Scott replied. ''Can't be half as breathtaking as the real thing, Joe. Wish we had time just to stand here and look.''

''It was amazing when the camera first came up and we started to move it,'' Fendell remembered. ''The next thing I knew, I had a hand on my shoulder. It was Christopher Kraft, who was looking at the TV image and just shaking his head. Everybody in the control center came to a dead stop. They had no idea that this thing was going to look this good.''

Scott and Irwin wished they had time to admire the Hadley-Apennine region that surrounded them. The indescribable blackness of space contrasted with the brilliant silver-gray of the lunar landscape and they stood knowing they were the only life on a barren, airless Moon that was billions of years old. Irwin was responsible for loading the geopallet and all the related equipment on the rear of the rover and after he had finished the loading, Scott took the dust brush to dust him off. Irwin had fallen and his lower suit was now covered with lunar dust. He would have to re-enter the LM to change some switch settings and stow the contingency sample, and he needed to be as dust-free as possible.

''Dave, this is Houston,'' Allen communicated. ''While you are stowing the brush there, just thinking ahead, we've got a couple of checks to carry out on the rover before you drive off from the site.''

''Yeah, that's good, Joe. Glad [to],'' Scott responded.

''Roger,'' Allen came back. ''We'll want you to look at the front wheel steering decoupling lanyard for us and then after that, physically try to turn the front wheels for us.'' Scott noted that the lanyard was taped down and that trying to move the front wheels produced no movement. The astronauts were about 25 minutes behind their timeline and Allen urged them to prepare to move out on their first traverse. Scott passed the lunar contingency sample up to Irwin, who stowed it in the LM while Scott returned to the rover and announced he was taking the TV camera off line, in preparation for the first EVA and to initialize the navigation system. Irwin returned from the LM and both astronauts mounted their Hasselblad cameras to their chest mounts. Then they climbed onto the rover, buckled their seatbelts and set off on the first traverse of EVA No. 1.

Because the crew was some 25 minutes behind the planned schedule, Scott drove with deliberate speed southwest to the edge of Hadley Rille, and would then follow the rim of the Rille toward Elbow Crater and their Station 1 stop nearby. Scott found the LRV to be very nimble in /6 -G, even with just rear steering. Four minutes into the first traverse, he reported the LRV's performance to Houston.

''The Rover handles quite well. We're moving at an average of about eight kilometers an hour. It's got very low damping compared to the one-G Rover, but the

Mare Imbrium basin was formed 3.8 billion years ago from the impact of a comet or asteroid, which created the Apennine Mountains and caused molten material to rise to the lunar surface and spread out, eventually cooling. Sample No. 15556 is a vesicular basalt having many gaseous bubble pockets. (NASA)

Mare Imbrium basin was formed 3.8 billion years ago from the impact of a comet or asteroid, which created the Apennine Mountains and caused molten material to rise to the lunar surface and spread out, eventually cooling. Sample No. 15556 is a vesicular basalt having many gaseous bubble pockets. (NASA)

stability is about the same. It negotiates small craters quite well, although there's a lot of roll. It feels like we need the seat belts, doesn't it, Jim?'' ''Yeah, really do,'' Irwin responded.

''The steering is quite responsive even with only the rear steering,'' Scott continued. ''It does quite well. There doesn't seem to be too much slip. I can maneuver pretty well with the thing. If I need to make a turn sharply, why, it responds quite well. There's no accumulation of dirt in the wire wheels.'' ''Just like in the owner's manual, Dave,'' CapCom Allen answered. ''Well, we were bouncing and skimming along,'' Irwin wrote in his memoir, ''and to our amazement no dust was being thrown up. The big concern had been that we'd be surrounded by a cloud of dust that might keep us from seeing where we were going and prevent us from making any observations. Not so. The fenders worked like a dream in keeping the dust down.

''At one point we came over a little rise and there was a crater about twenty feet deep right in front of us. Dave made a quick left turn that threw the vehicle right up on the two right wheels. I felt sure we were going to flip. What if the thing did roll over and pin us underneath it? Could we ever release those seat belts so we could get out from under and turn the Rover back over? We never had to find out.''

Scott quickly learned that he could not take his eyes off the route directly in front of them at the speed they were traveling because of the blocks and subdued craters. Driving the LRV required focused concentration, but the spectacular panorama in front of them made this difficult. Irwin had the task of looking wherever they drove and describing to Houston what he saw. He also conducted geologic observations while Scott was driving. The two astronauts finally spotted Hadley Rille and while Scott drove along the edge of the Rille, Irwin gave detailed descriptions of their observations. Both exclaimed how large the Rille was, at approximately 300 meters deep and over 1.5 kilometers wide. Allen asked Scott how the rover was handling with the loss of front steering.

"Apparently, your front wheels are tracking straight ahead, is that correct?" Allen asked.

"That's correct,'' Scott responded. "And, of course, when we turn, they dig in, and it makes the rear end break out. But it's okay; we can handle it.''

It was then the two astronauts got the same idea of perhaps venturing down into the Rille with the rover, and decided to have some fun with their CapCom.

"I might add to Jim's comment,'' Scott told Allen, "that the near side of the Rille wall is smooth without any outcrops, there by St. George. The far side has got all sorts of debris. It almost looks like we could drive down in on this side, doesn't it?''

"Stand by on that, Dave,'' Allen cautioned, obviously worried. Irwin decided to really give Houston a start.

"I'm sure we could drive down,'' Irwin added. "I don't think we could drive back out.'' Both astronauts chuckled at that, knowing Mission Control was alarmed at the possibility. In truth, each EVA was very carefully established and would be followed according to their Cuff Check List. Driving into the Rille was not part of the plan. The idea was discussed in the traverse planning meetings because of the variety of rocks that could be collected that had rolled down the sides of the Rille. However, doing so entailed considerable risk as the angle of the Rille walls could exceed the rover's hill-climbing ability. The idea was discarded in the discussion meetings.

Scott drove on to Elbow Crater, and soon found it, though it had not been easy to spot because it was such a subdued crater. He stopped the rover and the astronauts unbuckled their seatbelts and dismounted for their Station 1 sampling and photography. Scott aligned the High-Gain Antenna toward Earth to permit video of their activities and in Houston, Ed Fendell punched the controls to bring the TV camera to life and begin the pan of the area.

"When you see the pictures at each stop,'' said Fendell, "you'll notice that the first thing that happened is an almost 360-degree pan in 3-degree increments. That was something that was worked out between me, my guys and the USGS guys who were doing that for the Lunar Surface Team in the Backroom. We did a Wide Angle Pan (WAP) at every site. At the Lunar Module or when the crew pulled up to a site, the first thing we did was a complete pan in 3 degree increments. The team in the Backroom would take a Polaroid picture of the TV set each time the camera stopped. Then they pasted those photos together so they would have something in front of them on their desk so they could request things they wanted to see for their planning. They did this because they couldn't get the videotape back soon enough from the TV people. This gave them a complete panorama of each station stop.''

Scott commented that there was a fair amount of dust on the rover from their traverse, and Irwin complained there was so much dust on his camera that he could hardly see the camera settings. The astronauts spent fifteen minutes at Elbow crater taking their samples and additional photographs. When they discovered a desirable rock they wanted to collect, Scott would hold the sampling bag and Irwin would pick it up with the tongs and place it in the bag. They were always careful to call out the sample bag number. More interesting discoveries awaited, however, and they were admonished by Allen to proceed onto St. George Crater. Already, the astronauts had learned that the first order of business once on the rover was to fasten their seatbelts.

''Okay, Joe, the time consumer here is the seatbelt operation,'' Scott told Allen, ''because we definitely need them; and in /6 -G, we don't compress the suits enough to be able to squish down and get the seatbelt locked without a certain amount of effort.''

''Roger. We understand,'' Allen responded.

''I'll tell you, it's a good seatbelt design,'' added Scott. ''It's a great seatbelt design. Okay, let's check the Drive Enable. They're all on. Drive Power is on. Steering Forward to Bus A. Fifteen Volts DC. Ready to go, Jimmy?''

It took Scott and Irwin about seven minutes to drive to St. George Crater, which was Station 2 of EVA-1. They got off and Scott once again oriented the High-Gain Antenna and powered up the TV camera. Fendell brought the camera up to begin surveying the area around Station 2 while Scott and Irwin began examining a large rock up slope of where they parked the rover. The massive Rille dominated their view down slope and Scott could not help himself, exclaiming it was the most beautiful thing he had ever seen. The stark beauty of the Moon was something virtually all the astronauts would comment on during their explorations. As Fendell focused the camera on the rock Scott and Irwin were examining, Joe Allen ventured a guess that the rock was probably not older than 3.5 billion years old.

''Can you imagine that, Joe? Here sits this rock, and it's been here since before creatures roamed the sea in our little Earth,'' Scott marveled. The thought must have occurred to Scott that the rock he was looking at had been resting at that location undisturbed for a duration of time that was nearly inconceivable to the human mind. It also occurred to him that after billions of years, he - Capt. David R. Scott - was about to move it from its position of nearly eternal rest. He reveled in that moment in time as he turned the rock over to examine the soil beneath. At this stop, the astronauts employed a new tool, a rake designed by geologist Lee Silver. The rake permitted lunar soil to pass through but retained pieces of rock larger than half a centimeter. The astronauts put the rake to good use during their three EVAs. Scott and Irwin took samples broken from the rock and then took core samples using the core tubes that Irwin drove into the lunar surface with the hammer. The core tubes were removed, each end was capped and they were then returned to the rover. The astronauts were on the slope of Hadley Delta near the rim of St. George Crater for over three-quarters of an hour.

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