In the March 27th Space News, Mars Society President Robert Zubrin again seeks to direct the national space agenda to his ends in his Commentary [“The Vision at Risk,” page 26]. While Dr. Zubrin is generally on the right path with regards to the Vision for Space Exploration being at risk, I must nevertheless mark strong disagreement with one of his early contentions, in which he sets up three points from an editorial by Dr. Paul Spudis, advocating a strong lunar focus in our near-term efforts, in order to refute them.
The first point is that “studying lunar cratering will allow us to understand the processes of mass extinctions on Earth,” which he refutes with “the Moon’s lower gravity gives it a lower impact rate than the Earth, and it’s lack of an atmosphere or biosphere makes impossible any studies of the relevant post-impact terrestrial phenomenon that cause and shape mass extinction.”
It is true that the Moon receives a lower number of overall hits than the Earth due to its lower gravity (also because of it’s smaller cross-section, as well as the gravitational warps created by its proximity to Earth), but there is still no better place to study the impact flux over time than on the Moon. The Earth herself is too ever-changing, Mars is out where Jupiter provides a larger impact on object trajectories, Venus is still worse with its volcanism, and Mercury is too close, for the moment, to the Sun.
There is no better place to do so than the Moon (see 25 Good Reasons below). The importance of doing so rests on an astrophysical theory that in the Sun’s 225 million to 250 million year elliptical orbit around the galactic core, the Sun moves up and down — something like a carousel horse — through the galaxy’s equatorial plane where the bulk of the material is located. The period between the passes through this plane is estimated to be about 30 million to 35 million years, or about eight times per turn around the galactic core.
I doubt this theory, but what gives it currency is the spooky pattern being found in the impact record as we accumulate confirmed craters here on Earth. So while I disagree with the theory, I have no better explanation and cannot dismiss it because the historical record is there. I believe it is important to go to the Moon to look at the crater record (what I call sizing, counting and dating), not just to look at the composition of impactors, but also to see if there is in fact periodicity in the crater record, and if there is, where are we in the cycle?
This is pretty important stuff, because it ties directly in to the security aspect of the Vision for Space Exploration, as well as the scientific and commercial aspects. We do need to know more about the threat of potentially hazardous objects, both nearer the Sun and farther away, because asteroids do not care if they destroy our civilization. Asteroids and comets have no hate; they are indifferent to our existence. The ballistics were worked out aeons before we came along.
This is why Dr. Zubrin’s emphasis on the terrestrial post-impact effects is misdirected. The point is to tie the changes in the impact record as recorded on the Moon with geological data we are accumulating here on Earth. This can be supplemented by studying the high-energy particles that have accumulated in the regolith [lunar surface material] over the aeons to tell us more about the regions of the galaxy that our Sun has moved through, as well as the changing isotopic ratios of solar wind implanted elements to tell us how our Sun has changed over time.
So I think Dr. Zubrin is dead wrong on this one. His next point of refutation is: “Lunar activities will provide us with practice for exploration of other worlds,” which he dismisses as “false because while we can practice for operating on other worlds on the Moon, we can do much more in that line at 1/1000th the cost in the Artic.”
Again, I disagree. This time because of vacuum discipline. I maintain that nothing substitutes for the dread paranoia of vacuum on the other side of the space suit/spacecraft than actually being in a vacuum. This can be done in space and on the Moon, but this cannot be done in the arctic, nor underwater, no matter how good the pretend factor. Another factor is practicing the movement of equipment in partial gravity, where our mind has to relearn the rules for motion vectors of objects being moved. Ultimately, I believe we will use a mix of arctic stations, underwater stations, space stations and lunar stations in preparing for the trip to Mars to give us the solid experience base we will need.
Dr. Zubrin’s last point for refutation is “the Moon base will provide an economic return by enabling the development of lunar solar power stations that will beam electricity back to Earth.” His reply being “a photovoltaic panel only receives twice the solar flux as it does in Arizona, and all of its increased output would be lost in the inefficiencies of the transmission system. Thus the useful output of a photovoltaic power station on the Moon would only be equal to one on Earth, while logistics costs to support it would be 100,000 times as great.”
True, but going back to the Moon to build photovoltaic power stations solely for Earth is a silly idea, though Dr. David Criswell, director of the Institute for Space Systems Operations at the University of Houston, does make some good points in that regard. It makes more sense to build a network of relays and beam the power to lunar robots (either autonomous or tele-operated), or practice beaming it to an L-1 station, so that when we finally get our act together and start building photovoltaic arrays in geostationary orbits we will have a solid base of experience for doing so.
So again, I think Dr. Zubrin is arguing the wrong point, and he pretty much clinches it for me when he states ” that goal can only be humans to Mars” later in the article. No, humans spreading out to the solar system and Mars is but one of the destinations — one that will be almost as important as our Moon and, in my opinion, the asteroids out to the belt.
But Mars is neither the destination nor the goal. The goal is for humanity, as stewards of this good Earth, to take her life out to the solar system and the stars (and to try to understand the life that may exist out there beyond our current ken). The destinations are beyond counting. Dr. Zubrin is right, though. The vision is at risk, though perhaps not in the ways he perceives.
This editorial is adapted from a blog post at the Selenian Boondocks website. Ken Murphy has over 15 years of experience in the international banking and finance fields, and currently works as an aviation analyst/underwriter at a private investment bank in Dallas. He graduated with honors from International Space University in 2001, and is co-chair of the 2007 International Space Development Conference.