Published online 16 July 2009 | Nature | doi:10.1038/news.2009.697

News: Q&A

The moonwalker

Harrison Schmitt was the first and last scientist to touch the lunar surface.

The only geologist in NASA's batch of 'scientist-astronauts' in 1965, Harrison Schmitt was also the only scientist to walk on the Moon. He served in the US Senate from 1977 to 1983, and now works as an author, consultant and businessman. He talks to Nature about his role in the Apollo programme and beyond.

The obvious question I have to ask is: what was it like, being on the Moon?

The visual image you get is awesome. Particularly the black sky, with a brilliant Sun — that's something you don't normally think about having anywhere, certainly not on Earth. The overall experience is dominated just by being there.

After your geological work on the Moon was finished, you threw your rock hammer to see how far it would go. Tell me about that.

The hammer was just extra weight that we'd rather have in the form of samples, and we were going to leave it there. So I just took a little rotation and tried to throw it as far as I could. Just to do it.

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You were one of six astronauts selected in 1965 specifically for your science backgrounds; you were the only geologist among them. Are there more geologist-astronauts in NASA's future?

They just announced the latest set of astronauts and there are no Earth scientists or field geologists in that group, in spite of my efforts. I think we need more than just one person who suddenly appears, by accident almost.

You were on the last mission to the Moon, Apollo 17, in 1972. Do you think we should go back?

The United States in particular needs to be capable and active in deep space. The Moon is the easiest part of deep space to get to, one with a tremendous amount of scientific potential. It is also a place where we can begin to learn many aspects of what it's going to be like to finally get to Mars. It opens the door to some extremely important energy resources that are present on the Moon and really available nowhere else: the fusion fuel helium-3.

Many people have argued that it is economically unfeasible to retrieve that helium-3.

Click here to read our Apollo special.

People say that, but it's sort of an offhand remark. I think it's based on a feeling that everything you do in space has to be expensive. It has been so far because it has been mainly the government doing it, and government projects are expensive. Private-sector projects tend to be less expensive by a significant margin.

Most people push for fusion as an alternative energy source for environmental reasons. What is your motivation?

I think it's going to take just about everything we have — every energy source that makes economic sense — to supply the demand that's going to result from 10–12 billion people on this planet all aspiring to the standard of living we're used to in the United States and Europe.

Most scientists believe that the Moon was formed when a giant asteroid slammed into Earth. You favour the theory that the Moon was captured by Earth's gravity. Why?

Computer models that give a very elegant solution to a Mars-sized asteroid collision with Earth haven't yet been able to take into account all of the information from the samples brought back by Apollo. The primary fact that makes me sceptical is that we know, from the group of samples brought back from the Moon called pyroclastic glasses, that there is a reservoir of volatile elements deep in the Moon that, under the hypothesis of a giant impact, should not be there.

Why do you think your view on Moon formation differs from that of the majority?

Since the early 1980s, there has been a growing love affair with computer modelling. We not only see that with respect to space science but also with respect to climate science.

Harrison SchmittCALTECH

You have been called a climate-change denialist. How do you respond to that?

I'm a geologist and an observer of nature, and I consider myself a realist. I think the geological evidence is very clear that Earth has been warming for several hundred years, about 0.5 °C every hundred years. It's not an unusual rate of warmth. There is, I think, absolutely no evidence whatsoever that carbon dioxide has much, if anything, to do with that. If you really study the process behind the Intergovernmental Panel on Climate Change, it's mostly the bureaucrats that have come to that conclusion because they want more power and control. It's a real problem that people who are trying to be realistic about climate are basically being shut out of the discussion.

As the only scientist who has walked on the Moon, a lot of people look to you as an inspiration. How do you think the fact that you are out of step with some majority views on science interacts with being a role model?

I hope it's very positive. Because if there's anything science should do, it's to continue to ask questions. The last thing science should do is to accept consensus.

President Barack Obama doesn't seem very enthusiastic about space or manned space travel. What message would you send to convince him of the importance of ongoing space exploration?

Strategically, it's extraordinarily important that the United States does not give up its leading role in space. It would directly and indirectly affect our relationship with essentially every other major nation on Earth if we did that. I would also say that, economically, having a very strong, vibrant and innovative space programme has paid extraordinary dividends in the past. There's no reason to think it would not do so in future.

China and India are planning manned trips to the Moon, and even some private companies are talking about it. Is having so many players a good thing?

I always believe competition is a good thing; I just wish the United States and Europe would wake up and recognize they're in a competition. I think that the American people, the Europeans and the Canadians would all find it highly unacceptable if China became the dominant space-faring nation and the United States withdrew from that arena. I think it would be the beginning of the end, frankly.

There are some who believe people have never been to the Moon. How do you deal with that?

In a population of more than six billion people, you are going to have a few who have some really strange ideas. 

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