In the mid-sixties, when I was still a graduate student, I have distinct memories of walking across the campus and looking up and seeing the daytime Moon in the Arizona sky very clearly. I’d be thinking to myself, gee, it’s only going to go around maybe 60 times before we actually try to land on it. Having grown up looking at the Moon through my telescope in the backyard and making drawings of the craters and so forth, it was kind of a personal relationship with the Moon.
In Kuiper’s day, it was initially planetary astronomy. He realized that going to the Moon you were looking at a rocky body. He brought in some of the first planetary geologists. Bob Strom is the most prominent of those—to this day he’s the world’s expert on Mercury, and the guy who figured out that Venus was resurfaced a few hundred million years ago.
Kuiper’s appreciation of geology actually came from a very odd thing. He got it in his head, correctly, that Mauna Kea in Hawaii would be a great astronomical observatory site. In the process of looking at Mauna Kea, he flew over the lava flows in Hawaii. He recognized what lava flows looked like from the air, and then when he looked through telescopes and subsequently orbiting spacecraft at the Moon, he realized he was looking at lava flows.
That sounds like a simple thing now—we all know the dark areas of the Moon are made of basaltic lava—but in the 1960s, before Apollo, there were other thoughts. Harold Urey, Kuiper’s great competitor—along with Kuiper one of the two founders of planetary science—thought the Moon was completely primitive, undifferentiated. He called it a Rosetta Stone: You could see what all the original building blocks looked like if you went to the Moon. But Kuiper knew what lava flows looked like from above, and realized he was seeing lava flows out there.
When Gerard Kuiper first got here, his charge was to map the Moon, and understand the geology of the Moon well enough to be able to land a person on it, because this was imminent. They were going to land somebody on there, and one of the hypotheses at the time was that the thing was just an electrostatically-charged clump of dust, and as soon as you stepped out of your spacecraft you were going to fall into dust as high as your eye.
It was an unlikely theory, but there was no way to prove it wrong, because nobody had done the research. And we were just a few years away from landing somebody there. That was why LPL got started to begin with, so one of the tasks was to make really good maps of the Moon and be able to choose places to land.
What they would do is go out to the telescope and take these gorgeous pictures of it, but of course it was what we call a point-perspective projection. It’s not even a round globe; it’s just what you see. What they would do is put those in a slide projector, take them down to the basement, and in the basement of LPL—I think it’s still hanging up there now—is a round sphere. They’d go way across the building and project this thing onto the sphere from a distance, and come around and take photographs of the sphere. They’d be able to get various perspectives of the Moon that you wouldn’t be able to see from Earth. Things that looked like ovals would become circles. The things those guys did in the days before digital image processing were amazing.
This was an exciting period of time when things were being done for the first time. In that kind of environment, this is where discoveries are made. If you’re the first person to ever look at something with a particular technique and a particular wavelength region, with some resource that no one has ever had access to before, the easy things are hanging there waiting to be plucked.
Kuiper and Frank Low and us—myself and the men who worked with me—we were plucking all the easy things. We were discovering water on Jupiter and a lot of things that with hindsight were easy. But back then none of us really felt comfortable. We were always pushing the limit of something, and never knew what was going to happen, and always surprised and amazed that we were achieving results that got national attention. It was a privileged time to be working in science.
Kuiper passed away at Christmas time, in Mexico, in 1973. That was just after the launch [of Mariner 10]. The first encounter with Mercury was March of ’74, so he missed it. That was a shame; he never got to see Mercury. But he had a crater named after him both on Mars and on Mercury.
Round about the time Kuiper died, we were beginning to get in people from outside with these other fields. The whole subject was already expanding with all this stuff, especially that came back from Apollo with all the samples, a huge amount of geophysics and oh, just the whole plethora of subjects that were coming along. People were being hired at LPL to take over or help with these other, outside subjects. So from then on we started expanding in all fields.