Are there senior citizens who need prescription drugs on the Moon? Does the religious right favor a Moon base? How about illegal immigrants, would they be willing to take Moon jobs that Americans don't want?
I'm sitting here trying to figure out what possible reason--other than science illiteracy at the White House--there could be for George W. Bush to announce a plan to build a Moon base. Manned exploration of Mars is even crazier.
As this space pointed out last month, minimum weight at departure from low-Earth orbit for a stripped-down, austere Moon base might be 600 tons, and at current NASA launch prices, it costs $15 billion to place 600 tons into low-Earth orbit. Fifteen billion is NASA's entire budget--and that's just the cost to launch the Moon thing, not to build it, staff it, and support it.
An Apollo spacecraft at departure from low-Earth orbit for the Moon weighed about 45 tons, and the manned part was
tiny--astronauts could not stand up or move inside--as most of the weight was fuel. Considering that Moon-base weight would also be mostly fuel, numerous launches firing 600 tons toward the Moon for the purpose of making a base would actually result in little more than a couple of metal huts, some supplies and some antennas. Program cost for the International Space Station, currently losing air pressure, is about $100 billion, and it does not leave orbit. A rough guess would be that to build something about the size of the International Space Station (ISS) on the Moon would cost at least twice as much, $200 billion. And the ISS itself is mainly cramped modules, supplies, and antennas.
What would astronauts at a Moon base do? I haven't the foggiest notion. Note that NASA has not so much as sent a robot probe to the Moon in 30 years, because as far as space-exploration advocates can tell, there is nothing, absolutely nothing, of value to do on the Moon. Geologists are interested in the Moon's formation. If there is ever a fusion reactor to meet the world's energy needs, the "helium three" on the Moon might prove useful, but fusion reactors are decades away from practicality, assuming they ever work. Spending $200 billion on a Moon base that does nothing would be pure, undiluted government waste.
And a Moon base would not only not be useful to support a Mars mission--it would be an
obstacle to a Mars mission. Any weight bound for Mars can far more efficiently depart directly from low-Earth orbit than a first stop at the Moon; a stop at the Moon would require huge expenditures of fuel to land and take off again. The landing, in turn, would accomplish absolutely nothing--any mission components on the Moon would have been sent there from Earth, which means they could have departed directly for Mars from low-Earth orbit at a far lower cost.
In the days to come, any administration official who says that a Moon base could support a Mars mission is revealing himself or herself to be a total science illiterate. When you hear, "A Moon base could support a Mars mission," substitute the words, "I have absolutely no idea what I am talking about." Hint to reporters: If any administration official says "a Moon base could support a Mars mission," quickly ask, "What was the fuel fraction of the Lunar Excursion Module?" The answer is two-thirds. The LEM was what landed on the Moon during Apollo, and rocket propulsion has not changed much since, meaning that any future Mars spacecraft that stops at the Moon will expend two-thirds of its weight merely to land there and take off again. This renders the idea of stopping at the Moon on the way to Mars patent drivel. (Actually only about 15 percent of the descent weight of the LEM returned to lunar orbit, so the fuel-fraction calculation for a Moon stopover is even worse.)
Now, about this business of going to Mars. The Red Planet is plenty interesting, and men and women are sure to go there someday. For the moment, talk of a Mars mission is complete bunkum.
The Apollo spacecraft weighed 45 tons at departure from low-Earth orbit: it was gone for about ten days, carried three people and traveled about 800,000 miles total. A Mars mission would be gone for a minimum of a year (probably longer), carry at least six people (a geologist, a biologist, two physicians, and two career astronauts would be a skeleton crew), and travel 100 million miles or more total (the distance to Mars varies significantly depending on the launch year). So let's make a conservative guess and say an austere Mars-bound mission would weigh 25 times what an Apollo mission weighed, at departure from low-Earth orbit.
Now we're up to an 1,125-ton spacecraft and a $28 billion launch cost. (Probably a Mars mission would operate in segments, with several robot supply ships departing long before the manned craft; but for the cost calculation, the driving factor is total weight.) Twenty-eight billion is twice NASA's budget and, again, that is just the cost to launch the thing, not to build the ship, staff it and support it. When Bush's father asked NASA in 1989 about a Mars mission, the agency shot back a total program cost of $400 billion. That's $600 billion in today's money, and sounds about right as a Mars mission estimate. This is assuming no pointless stopover at the Moon; add a Moon base and the price zooms toward $1 trillion!
We're getting into the range here of the national debt.
Some lunatics--I use that word in its astronomical context--have suggested a Mars mission could be done with a total spacecraft weight of only a couple hundred tons. Not if we want the people back! The manned part of a Mars ship would need incredible redundancy, perhaps two complete operating sections each capable of return to Earth, in case some failure occurs on the long transit. Radiation exposure will be far more of a factor in Mars travel than it was going to the Moon, which orbits within Earth's magnetic field, so many tons of shielding will be needed. The Mars ship will require a full operating theater and at least two surgeons on the crew, since what if the doctor is the one who gets injured? Probably an entire Mars ship would have to be assembled and sent there and back unmanned, just to ensure that the hardware works: meaning dozens of billions of dollars to fly an empty ship to Mars, and imagine how voters will like that. And even if the mission involves a very well-made spaceship with incredibly redundant system--and no president will authorize anything less, who would risk having to sit watching CNN show images of stranded astronauts dying on Mars?--there is risk a tragedy or fiasco.
One parting thought on the practicality of Mars.
Spirit, the rover that just landed there, weighs half a ton. Spirit cost $410 million to build and place on Mars--and it's about the size of a refrigerator, and does not come back. Mars-mission proponents want to send something to the Red Planet the size of an office building, and bring it back.
What NASA needs right now is not an absurd, bank-breaking grand mission: It needs to spend a decade researching a safer lower-cost alternative to the space shuttle.
And why might George W. Bush endorse a Moon base or Mars mission? Either he's a science illiterate surrounded by advisors who are science illiterates, or it's a blank check for aerospace contractors.
posted 11:32 a.m.
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