The nation needs an overarching goal for space that encompasses science and creates popular interest and excitement. Human exploration of Mars fits the bill perfectly. It would completely transform our understanding of the origin of the solar system and of the possibility of life beyond our small blue planet. And it can be done within the present NASA budget.
First, however, a true confession: I have been active in space projects since the very beginning, more than 50 years ago. To me, a base on the Moon is just the Space Station writ large ? and a lot more expensive. The scientific payoff is minimal and the cost exorbitant. Besides, we've done that. Habitation of Mars has at least some novelty -- but it too will soon wear off. Bases on asteroids or colonies out there in space? Forget it.
I don't buy all of the "human destiny in space" slogans -- I want exploration. Mars is the most promising target. There is nothing like it in the solar system -- Earth-like and accessible. So, let's look at the why and the how.
I want to know how Mars came about, how a planet assembled out of little planetesimals. How did it get hot enough to melt? Did radioactivity provide the missing energy or was there some other planetary heating process? Is the core still molten as on Earth, and what happened to Mars' magnetic field?
What about the Martian oceans whose historic existence is quite evident? Where did they go to and why? How much water is left? Volcanoes were once active producing huge mountains. Could the same events happen on Earth?
We can see evidence for weather in the Martian atmosphere, which in some respects resembles ours, yet is quite unique. Ice caps that shrink and grow with the seasons and over time. Giant dust storms that blanket the planet's surface. Can the climate models developed for the Earth account for what we see on Mars? And once we study the sediments in Martian rocks, will we find past climate changes that match what we know about the Earth's climate of the past millions of years?
The big question is the existence of life on Mars. One no longer expects to see "canals" or evidence of intelligent life, but we might find primitive organisms in the subsurface soil or in polar regions where there is moisture. Or maybe it will just be evidence of past life, now died out. Will it resemble any kind of terrestrial life in chemistry and form? More fundamentally, is creation of life a given if environmental conditions are right or is there something unique about the Earth? Answers to these questions impinge on philosophy and even theology -- and also on whether there is intelligence somewhere out in the universe beyond our solar system.
There is also the mystery about the origin of the two moons of Mars. Phobos and Deimos are tiny rocks, about the size of Manhattan, discovered by Asaph Hall in 1870 at the Naval Observatory in Washington. Are they captured asteroids? Not likely. Were they formed along with Mars? Not likely. Are they similar in composition? To find the answer we will need samples. How did they get into their peculiar orbits, with Phobos slowly shrinking into Mars, destined to crash? Were there other moons that have now disappeared? We don't yet know the answers, but they could hold the key to the puzzle of the origin of planets and their moons, including ours.
It's now nearly 30 years since the first unmanned probes landed on Mars -- and we are still a long way from bringing back samples for direct examination. The truth is that we are still decades away from answering the burning questions if we proceed with occasional probes -- ones that often fail and are not cheap. Beagle is but the latest example. Here is where a human presence can make a decided difference -- not necessarily on the planet's surface but close enough to control exploration in real time by tele-robotic rover vehicles. The ideal base would be on Deimos -- almost within reach of the planet -- directing exploration to different locations, returning and studying samples in a fully equipped laboratory and following up with more probes as necessary.
A Deimos base would be safer and a lot cheaper than a base on the Mars surface -- and would accomplish more. A manned mission to Phobos and Deimos amounts to a simple transfer of a habitat from Earth orbit to Mars orbit. It could be done sooner than establishing a Mars base, for about $30 billion over 10-15 years, well within the present NASA budget. A comparable sum has been spent since 1967 on 36 unmanned missions to Mars, more than half of which failed.
How to kick it off? I think that the initiative has to come from the private sector. It would take only one person, a real visionary, to get it started -- mainly through publicity: a book, a documentary, a TV special. The next step is to get the aerospace industry to contribute the necessary design and detailed engineering studies, including all the trade-off calculations. How much does it cost in extra propulsion to shorten the time of transit to Deimos and back, and what is gained by keeping the mission to less than a year or so?
The manned Ph.D. project to Mars is a worthy goal: It is not just a publicity stunt, but true scientific exploration that also benefits life on Earth. At the same time, it provides inspiration for all of the citizens of the planet Earth.
S. Fred Singer is a physicist and was the first director of the U.S. Weather Satellite Service.