President Trump can “make America great again” by planning a surprising and easily affordable human exploration mission to the red planet Mars and its two moonlets Phobos and Deimos: PH-D, for short. JFK is remembered by many people mainly for putting Americans on the Moon, but he really just initiated the program.
The two moonlets of Mars were discovered in 1877 at the US Naval Observatory in Washington, DC. They are in near-circular, near-equatorial orbits around Mars. Deimos, smaller than the island of Manhattan, orbits at a distance of 6.9 Martian radii; Phobos, about five times larger than Deimos, is at 2.8 radii, with its orbit shrinking because of tidal friction; it will be gone in just a few million years. In past lectures, I have joked that the dinosaurs might have seen more Martian moons, now gone, “if they had had better telescopes.”
Notice that I did not suggest colonization of Mars—the current rage, a replay of the massive, wildly expensive and technologically infeasible Empire Project of the 1950s, envisioned by space pioneer Wernher von Braun. Unfortunately, this premature emphasis on colonization tends to color even realistic manned Mars projects as fantasy. Nor do I favor the business-as-usual continuation of unmanned missions to Mars, promising the eventual return of Mars samples for analysis in terrestrial labs.
The feds have traditionally supported exploration—including basic science, which does not promise an immediate pay-off. Indeed, that has been the rationale for building multibillion-dollar particle accelerators for high-energy physics and telescopes for astronomy. So the PH-D project, as I have nicknamed it, would fit right in—a combination of good science and high adventure. Even its cost is relatively modest—about $30 billion over 10-20 years, well within the current NASA budget, and about that of a half-dozen unmanned Mars missions. Its scientific return would be many times greater. Its public and international impact would be tremendous.
No Showstoppers
The PH-D project is basically a manned transfer from Earth orbit to Mars orbit, taking about six months; there don’t seem to be any showstoppers at all. A rough calculation has convinced me that ordinary chemical propulsion is quite sufficient—no need for any exotic schemes that require lengthy development. Any simple fuel, like kerosene, suffices, and any of the available oxidizers can do the job. No special rocket engine is needed; existing ones will do -–as explained below. And propulsion is surprisingly cheap—only a few percent of the total project cost; more than 95% of the cost is engineering and design—and the US has many well- qualified engineers.
Electric power—again no problem. Of course, solar photo-voltaic becomes more difficult at Mars distance, where solar energy is less than half that at Earth orbit. But the Russians have space-tested nuclear reactors, and units are available for purchase. I estimate that 100 kilowatts should do nicely and would even provide an adequate reserve of power.
Other issues, relating to maintenance and life support of astronauts, present no problems either; they have been mostly solved in the International Space Station. As in the ISS, one would recycle liquid waste, but not solid waste. With cheap propulsion and essentially unlimited payload, one simply carries more food and water. The same argument applies to maintaining a healthy breathing atmosphere.
Radiation is usually cited as the major health risk; but propellants turn out to be the most effective shield, especially against heavily ionizing particles of the incident galactic cosmic radiation—GCR. Once the astronauts set up their base on Deimos, the preferred destination, they can construct also a more permanent shelter against the omni-directional cosmic rays, the unidirectional meteor showers, and the occasional solar eruptions that can lead to penetrating particle radiation. Note that none of that protection is present in the ISS, but Deimos itself provides shielding against unidirectional radiation; it is only necessary to move to the opposite side.
Absence of gravity can lead to long-term health problems. The answer here, as in the ISS, is regular exercise, aided by artificial gravity from a centrifuge; such a scheme should be tested in the ISS.
Scenario of Deimos Base
Assemble propellants in low-earth orbit—LEO; then send to Deimos as “slow freight” – including a nuclear reactor, spare habitat, spare rocket engine, penetrators and rover vehicles equipped for return of samples; release penetrators that will provide also seismic data, and some rovers while underway to Mars. Send one habitat, two rovers and some of the propellant to Phobos—for use on the later sortie to Phobos and Mars surface.
Test the habitat-lab while in LEO with 5 astronauts aboard; then send them to Deimos on a “fast express” trajectory. Upon arrival, shield and activate the reactor; surround the habitat-lab with rocket propellants to provide additional shielding; set up a GPS system and weather satellites for Mars.
Start sample-return program, analyzing initial samples—and call for follow-up samples from different Martian locations or different depths, based on the initial analyses– all the while consulting with experts on Earth.
Sortie to Phobos and Mars Surface
Two astronauts depart for Phobos and meet two rovers, collect samples of regolith and deeper, and send them back to Deimos base, then move on for a powered landing on a preselected Mars site, meet rover vehicle there, collect samples, set up an experimental equipment, and then take off for return to Phobos and thence to Deimos base. Note that take-off from Mars requires only our small rocket—while a direct return to Earth would have required a special, high-thrust rocket, capable of lifting the large propellant load necessary for transit to Earth.
Deimos Base vs Mars Base
There is no question that a Deimos base is easier to set up, much cheaper, safer, and better in all respects than a base on Mars. Besides, it can be accomplished much sooner, perhaps within 10-15 years.
A Mars base does not confer mobility, does not provide a view of the rovers; from Deimos one can view the surface from pole to pole for up to 40 hours. [Deimos is in a near-synchronous orbit, with an orbital period of 30.3 hours, just a little longer than the spin period, 24.7 hours, of the planet.]
On Mars, because of its gravity field, meteor impacts are more frequent and also more energetic; there is interference from Mars’ atmosphere, from winds, and from dust storms—while on Deimos one gets a ‘free’ vacuum, essential for most lab instruments, such as mass spectrometers, electron microscopes, etc.
Scientific Questions: Planetology (and learn also about the early history of Planet Earth)
The origin of Phobos and Deimos is a real puzzle: Initially, I applied a modified (‘push-pull’) tidal theory[1] to extrapolate their present orbits backward in time; but I do not believe they are captured asteroids—although that’s what many textbooks claim; it’s just too improbable. Nor were they formed along with Mars; it leads to an unstable solution. I now believe they are the remnants of a Mars-moon --M-m, captured gravitationally, akin to Earth-Moon, but into a retrograde orbit; the other, heavier fragments of the M-m have already spiraled in and disappeared, impacting on or near Mars’ equator.
Some research questions—and learn also about the early history of Planet Earth
1. Why do Phobos and Deimos, presumably related, look so different? Is it just the regolith and is it based on the difference in their orbits?
2. Are Ph and D solid rock or rubble piles?
3. Are there tiny moonlets orbiting Mars between Ph and D?
4. Explore orbiting dust at Ph and D.
5. Explore evidence for ancient impacts of fragments near Mars’ equator.
6. Establish history of Mars’ obliquity by tracing W-182 tungsten isotope, from the radioactive decay of hafnium.
7. Was capture of M-m essential in heating Mars by tidal friction to produce its iron core?
Scientific Questions --Meteorology And Climatology—and test theories of causes of climate change and ice ages
1. Test forecast models developed for Earth on Mars weather predictions.
2. Test current climate models against Mars observations: predictions of dust storms; test analyses of Martian polar -layer deposits against ice-age theories and periods of oscillation of Mars obliquity, precession and orbit eccentricity.
Scientific Questions—Crypto-Life And Paleo-Life
Is life unique to the Earth—as some believe? This is a very basic issue with philosophical and even theological overtones
Look for hidden life forms, taking into account that life may have developed several times, independently, at different locations, and been wiped out subsequently. These life forms may be ephemeral and unable to survive for more than a few hours—hence undetectable in Mars samples returned to Earth, as currently planned. It may be advisable to develop also techniques for detecting life in situ, for ultra-fresh sampling.
Ancient life, now dead, may be detectable in some sort of fossil form. Its formation likely required the presence of liquid water—i. e., survival of oceans, lakes, or simply pools of water for a sufficient length of time. Note that these life forms may not have been based on carbon, but possibly on silicon. Note also that use of a Deimos base minimizes chances of both forward and back-contamination of Mars with terrestrial biota.
Conclusion
We believe that the scientific yield of the PH-D mission more than justifies such a project. Its impact on the public here and abroad would be akin to the Apollo project and fully supports president Trump‘s goal of “making America great again.”
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A Brief History of the Ph-D Concept
In 1977, NASA awarded me a $8,000 study grant [H-27272B and H-343115B], administered by its Marshall Space Flight Center in Huntsville, Alabama; I delivered a 2-volume report a year later, but heard nothing more from NASA. My first talk exposing the concept was given at JPL, invited by Don Rea. The first open publication was based on my presentation at the 1981 The Case for Mars conference in Boulder, CO, and published in the conference book by the American Astronautical Society, Penny Boston, ed. ISBN 0-87703-197-5 or -198-3, San Diego, CA, 1984.
