Thursday, December 16, 2004
Jeffrey Kargel, a USGS scientist, published a discussion about the significance of Mars's watery past to the prospect of life on Mars today. Eleven paragraphs of dry science are followed by one paragraph on what the possibility that life might exist on Mars today means to human exploration of the red planet. Kargel's conclusion: "Given what we now know about Mars, planetary protection considerations require the assumption that Martian life exists, until we learn otherwise. All possible care must be taken to avoid cross-contamination between Earth and Mars. Before proceeding with sample returns or human missions to Mars, we must review measures for planetary biological protection." (Science, vol. 306, 3 December 2004, p. 1691.)
That's quite a bombshell conclusion Kargel, an expert on cold climates, comes to: we should assume life exists on Mars until we learn otherwise. The significance of his assumption is the worrying part for those of us who advocate human exploration of Mars, not just by sending robots, but by sending people. Kargel's desire to protect Martian microbes and avoid back contamination on Earth leads him to promote very strict limits on sending humans to Mars. He is said to favor sending robots to Mars to search for life there, rather than bringing samples back to Earth or sending humans. If humans do go, he says here "To be humane to them, you send them to Mars first with some reasonable knowledge that they're not going to be infected, so you have to do your homework first." He adds, "Secondly, you give them the means to live on Mars the rest of their natural lives."
It's hard to imagine waiting to send humans to Mars until we have "some reasonable knowledge that they're not going to be infected." First, Mars is a planet. Even though it is smaller than Earth it's surface area roughly equals our planet's land area. To rule out human infection we'd have to send lots and lots of robots to search for life there and essentially rule it out. Waiting until the robots discover life on Mars or rule it out would delay human exploration of the planet for multiple decades. Some space scientists would prefer that approach anyway. Dr. Jeffrey Bada, of UCSD, in a talk hosted by the San Diego Mars Society in 2004 argued against sending humans until we are sure Mars has no life. His rationale was to protect the Martian environment from contamination so that if we do discover life there, we can be sure it is native Martian life and not an Earthling invader.
Second, it's a completely unrealistic and unaffordable mission requirement to ensure that any astronauts we send to Mars will have "the means to live on Mars the rest of their natural lives." Sending humans to Mars will be expensive enough as it is without requiring that the first mission send enough resources for 4-6 people to live on Mars for 25 years or more. (Don't believe the trillion dollar myth. Reasonable estimates for a humans to Mars program range from $30 to $60 billion over 10 years and $2-5 billion per mission after that.) Now, if Kargel were proposing a colonization scheme in which we would send people one way to colonize the planet, that might be something advocates of human exploration could get behind. But that's not what he appears to favor. What he seems to have in mind is a one-way mission sent one time and that's it. That's not reasonable.
Third, although it's more expensive to send humans to space, humans on the scene would do much better science than robots would. Just think about the fact that Spirit and Opportunity travel at about 2 inches per second and consider the distances they've traveled in the year they've been there. Then imagine how far humans might have gone in the same time. Then think about the wealth of knowledge discovered by the rovers and imagine how much more would have been discovered by several scientists working on Mars with a full lab in the same time. There is no comparison. Humans would have accomplished so much more.
We can't let concerns over whether life on Mars is dangerous to us or we are dangerous to it stop us from going there. That would be giving too much counsel to our fears.
NASA already has planetary protection protocols for protecting Mars from contamination and Earth from back contamination. Indeed, the Outer Space Treaty requires such protocols. And it would be irresponsible not to take reasonable protective measures. Which is why it's painful to see Robert Zubrin, founder and head of the Mars Society, saying this: "For NASA to spend hundreds of millions of dollars to prevent Martian microbes from coming to Earth in their samples would make as much sense as for the U.S. government to set up a program to stop travelers from bringing Canada geese across the U.S.-Canadian border."
Well, no, actually, it's not quite the same. While it's true that meteorites from Mars land on Earth occasionally. There is to date no evidence (the controversial Antarctica meteorite notwithstanding) that any Martian microbes have piggybacked their way to Earth on any one of those rocks. As far as we know, nature is not already doing what NASA seeks to avoid. Unlike the flocks of geese which migrate from Canada to the U.S., there are no flocks of microbes migrating from Mars to Earth.
Wednesday, December 08, 2004
Let's just build a new Hubble
Now the National Academy of Sciences has weighed in on the side of sending a shuttle mission.
They have a point. The cost of sending a robot to the Hubble simply to de-orbit it has been estimated at about $300 million. However, the estimated cost of sending a robot to do the tricky repair work necessary to keep Hubble running is a hefty $1.6 to $2.3 billion. Worse than this is the fact that the work is so hard for a robot to do that the prospect of a successful robotic rescue mission is not good.
Shuttle astronauts have successfully serviced Hubble four times in the past. However, the cost of each of those missions has been about $1.3 billion, meaning Hubble's cost is $5.2 billion more than its original cost of $2 billion.
Hubble was designed to last about 15 years. It was launched in 1990 so 2005 is when it was designed to end anyway. For the life of me I don't understand why nobody on the inside is stepping back and simply recommending that we build a new Hubble and launch that into orbit. For the cost of fixing a telescope that is near the end of its designed useful life we could have a brand new telescope.
We shouldn't save Hubble. If people weren't so sentimental about Hubble, or weren't using it to advance an unrelated agenda (for instance the way my own Mars Society is using the issue to promote humans in space) we would look at this issue practically and scrap the old telescope and launch a new one. When you own an old car you don't spend as much money to fix it as it cost to buy it in the first place. You sell the old car and buy a new one. Why should it be any different for space telescopes?
Saturday, December 04, 2004
Recognizing the right of humans to occupy Mars.
Unknown to many outside the space community environmental concerns are gaining currency among advocates of space exploration and threatening human exploration of space. On one side are those who fear that human activity in space will contaminate the pristine environments of other planets. Mars is a special concern because of the possibility that life might exist there. On the other side are those who don't believe that environmental concerns should stop human exploration. There is a vast middle ground between those who oppose human exploration entirely because of the risk and those who would ignore completely any environmental concerns.
But here's a proposal from the environmental side that appears to open the door to human exploration of Mars. The two scientists in the article below propose setting aside seven regions on Mars for preservation and protection from human influence. In the course of their proposal they make a remarkable concession to human exploration of the planet: "It is the right of every person to stand and stare across the beautiful barrenness and desolation of the Martian surface without having to endure the eyesore of pieces of crashed spacecraft scattered across the landscape."
Although this statement makes a fetish of the barrenness and desolation of Mars's current surface condition, which is a problem many space environmentalists have, they come down in favor of recognizing that humans have a right to be on Mars. After all, one pretty much needs to be on Mars to "stand and stare" at its landscape, whatever the condition of that landscape. That's a step in the right direction.