Cassie Conley, NASA's Planetary Protection Officer, says that humans will cause problems on Mars:
So when humans are going to go to Mars – not before, but when humans are going to go to Mars – we will allow small local regions, carefully selected regions of Mars to become somewhat contaminated with associated human commensal organisms, and organisms required for food growth. We know that it’s impossible to sterilize a human and still have the human be alive, given that humans are obligately required to have commensal organisms. It would kind of defeat the purpose to send a dead human to Mars.
I think the solution is obvious: send zombies to Mars! I'm surprised Dr. Conley didn't think of it. Zombies are already dead, so you don't have to worry about the commensal organisms. Zombies could explore all of Mars and, since they're dead, not contaminate anything once they're sterilized. Sterilization has another advantage: the zombies won't rot, so they'll last a lot longer.
How long the zombies last is the only problem I can think of. The faster we can get the zombies to Mars, the more work we get out of them before they fall apart. There's no way we're getting as many extended missions with zombies as we did with the Spirit and Opportunity rovers.
Keeping the zombies fed is simple. Freezers that automatically warms and dispense cow brains when the zombie performs the assigned tasks will be all that's needed to keep the zombies going.
Of course, only zombies resulting from curses or ill-conceived pacts with sinister forces can be used. Diseases that cause zombie formation might contaminate the Martian environment. As an added advantage, zombie masters can see through the zombies' eyes and control the zombies without the need for expensive radio equipment. The communication is instantaneous, eliminating the time lag problem.
Zombies offer many advantages over humans, anyway. First, if the spacecraft blows up or fails somehow, no one will particularly get upset about the zombies, especially since they were already dead. It's not like there's a shortage of zombies: people are killing them left and right without putting them to any good use like space exploration. Because they're dead, zombies suffer far less from radiation, a major problem in getting living humans to Mars. It's not like the zombies can get cancer or will become unable to have children because of the radiation. As the zombies break down and parts fall off, we'll all be sad, in the same way we're all sad for the Spirit rover, dragging it's broken wheel as it drives backward. Who knows, though? Perhaps important scientific discoveries will be made by damaged zombies, as was recently made by the Spirit rover when the broken wheel uncovered water-formed silica.
In the past years, zombies have become more intelligent and agile. The lumbering zombies from the 1950s, when our tame Nazis was trying to beat the Soviet's tame Nazis to space, would never function as space explorers. But as the latest movies have shown, modern zombies retain far more of their intelligence now, and can run at amazing speed. No, they won't ever be as smart as a Ph.D. trained in the planetary sciences, but zombies don't go chasing after their ex-lover's current girlfriend while wearing diapers. Yes, the zombies do try to eat non-zombie humans brains and spread their zombie-ness, but that's still far less troubling than using Nazis to jump-start your space program.
The next time you're attacked by zombies, don't slaughter them indiscriminately. Capture a few for the space program.
That's one small, badly coordinated step for a zombie, one giant leap for mankind.
(Y'know, that does bring up one problem, not technically significant, but emotionally so. The first words spoken on Mars will be "Brains!" Somehow, that's a little disappointing. On the other hand, 40 years after those first famous words on Mars, historians won't be arguing over whether the quote was screwed up…)