Showing posts with label nasa. Show all posts
Showing posts with label nasa. Show all posts

Thursday, March 31, 2011

Space Travel: Science Fiction's Biggest Underachiever

In 1968, futurist Arthur C. Clarke wrote 2001: A Space Odyssey, which quickly became one of the most popular science fiction novels of the 20th century. In Clarke’s vision of tomorrow, mankind in 2001 would have ring-shaped space stations that rotate to provide gravity, permanent lunar colonies which people routinely visit for business meetings, and fully-functional (if evil) artificial intelligence. The zeitgeist of the late 1960s, at the height of the space race, was one of unbridled optimism in the future of space travel. Just two years before Clarke’s novel was published, Star Trek had first premiered. It seemed inevitable that we were destined for the stars.

Looking at the world around us, it is easy to be disappointed at how space travel has progressed. The world today looks nothing like Star Trek, or even 2001: A Space Odyssey. After the Apollo missions ended in 1972, something strange happened that few futurists anticipated: mankind stopped exploring space, and turned inward to focus on problems at home. NASA’s budget was slashed. To the extent that space exploration progressed, it was done almost exclusively by robots rather than manned missions. If we were able to go back in time to the late 1960s and tell people that we would indeed have a permanent space settlement today, they would almost certainly envision something far grander than the International Space Station.

Why were the space enthusiasts wrong? The biggest obstacle has been political, not technological. In my opinion, political trends are much more difficult to predict than technological trends. From a 1968 perspective, the US and USSR were locked in a Cold War that would soon extend far above the earth’s surface. It was much easier to forecast the trends in space technology than to predict that the USSR would throw in the towel on the space race by the mid-1970s, and cease to exist at all soon thereafter. With the collapse of the USSR, the impetus for a space race has disappeared. No nation is willing to spend large sums of money exploring space without the threat of a rival beating them to it.

In light of this political reality, the exploration of other worlds seems to be permanently on hold. I do not envision this changing any time in the next couple decades. Although President George W. Bush called for the United States to return to the moon by 2020 and NASA stated that a permanent manned lunar base would be operational by 2024, it is highly unlikely that these goals will be fulfilled. The US is simply not motivated to do so.

Additionally, the economics of space travel have changed significantly since the Apollo missions. Due to advances in computer technology, it is now much cheaper to send robots to explore other worlds than it is to send human astronauts. Robots don’t need food, water, and air to keep them alive, and don’t need a return trip to earth. They can do almost everything a human astronaut can do, and can wirelessly transmit the data back home. Indeed, NASA has had some great achievements exploring our solar system, but the pioneers have all been robots.

It is possible that the private sector will be able to pick up part of the slack left by governments. SpaceShipOne, the first privately-owned spacecraft, claimed the Ansari X Prize in 2004. However, private space travel will never progress beyond orbital missions for super-rich adventure-seekers until there are some fundamental breakthroughs in rocketry. It currently costs $10,000 to send one pound into orbit, because rocket fuel itself is responsible for 90% of the weight of a rocket. As long as fossil fuels are the standard propulsion technology, human space travel will continue to be unaffordable for most people. Futurist and theoretical physicist Michio Kaku suggests that rockets could be powered by lasers instead of by fuel. Lasers on earth could fire at a water tank, vaporizing the water and propelling a rocket upward. Since the thrust would come from the ground instead of the rocket itself, it would eliminate the need for fuel and make rocketry 10 times more efficient.

Although this technique has been demonstrated to work in prototypes, it will be a long time before it can be applied to something as large as a rocket. Although many emerging technologies few people have imagined will suddenly take us by surprise, I think that space travel is something that will continue to disappoint us for many years.

PREDICTIONS:

As of 2025 – No human being has set foot on the moon since the Apollo missions.

As of 2035 – No human being has ever set foot on Mars.

Saturday, December 4, 2010

Arsenic-Based Life

This week, NASA geobiologist Felisa Wolfe-Simon announced the discovery of arsenic-based microbes in Mono Lake in Yosemite National Park. This is a major scientific bombshell that is causing biologists to re-examine much of the conventional wisdom about what life is. All life, from the smallest bacteria to the largest redwood tree, was thought to be based on five elements: Carbon, hydrogen, oxygen, nitrogen, and phosphorus. These elements are crucial ingredients in life’s software – DNA and RNA molecules – as well as life’s fuel – ATP molecules. But now scientists have discovered organisms that use arsenic instead of phosphorus in their biochemistry, which was thought to be impossible. Most organisms are poisoned by arsenic because it is highly reactive, destroying the DNA and ATP found in living cells. But this new species of extremophile not only thrives in a lake with an arsenic concentration 700 times what the EPA deems safe, but actually manages to incorporate it into its DNA and ATP. This is more than just a strange new species with an interesting quirk; many of those are discovered every year. This is a radical redefinition of what “life” is.

Although these microbes appear to have evolved from more traditional forms of life, their mere existence opens up the possibility of a "shadow biosphere" on earth. All known living things have descended from a common ancestor, but what if organisms with other biochemistries are living right under our noses undetected? Might they provide evidence of a second genesis on earth? If life has developed twice, with two different biochemistries, it would prove that the evolution of life on earth was not just a one-in-a-trillion fluke, and would greatly increase the likelihood of life developing on any suitable world.

The discovery of arsenic-based life has important applications in the search for extraterrestrial life, which is where NASA comes in. For ages, scientists have pondered about the possibility of completely new types of life. A handful of astrobiologists (and a slew of science fiction writers) have speculated that extraterrestrial life might be too alien for us to even recognize as life. In fact, this is one possible explanation for Fermi's Paradox, which questions why we haven't already found life if it is commonplace in the universe. In light of this week's discovery, this explanation has become a lot more plausible. Perhaps DNA, reliance on water, and cells are just unique traits of life on earth, and we are barking up the wrong tree if we focus solely on finding them elsewhere.

Others have believed that “life as we know it” was the only type of life possible. This has been the dominant mindset of NASA for several decades, and is the basis of NASA’s search for life. NASA has concentrated its efforts on locating worlds similar to our own, where the conditions exist to permit the development of life as we know it. This generally means finding worlds with water on them, located in the “Goldilocks Zone” of their solar systems where they are neither too hot nor too cold to sustain life. This, of course, has been premised on the assumption that any extraterrestrial life is probably not too different from the life we know.

The discovery of arsenic-based life has cast doubt on this approach. If a new form of life can be found in Yosemite National Park, we can scarcely imagine how different extraterrestrial life must be. NASA’s obsessive search for earth-like planets may be overlooking a huge number of worlds where life may exist, in forms unknown to us earthlings. If it is possible for life to exist with a completely different biochemistry from our own, then it’s equally possible that it could thrive on worlds far different from our own, under conditions that have traditionally been regarded as hostile to life.

NASA will need to do a lot of soul-searching in light of this week’s discovery, and reevaluate how it determines if a world is potentially suitable for life. For the first time in history, a long-standing astrobiological question has been answered: Is “life as we know it” the only type of life possible? We now have our answer: It is not.