While I share Dr. Park's frustration with the lack of distance traveled by astronauts since the Apollo Program (especially because the last lunar landing occurred before my birth), I disagree with his implication that robots are more suited for missions to Mars than humans. I appreciate Dr. Park's enthusiasm for science, but in my opinion, exploration is much more exciting.
In his editorial, Dr. Park stated that "astronauts on Mars, assuming they are in any condition to go exploring after nine months in zero gravity, would be trapped in their spacesuits, with no sense of touch or smell. They would have only the sense of sight -- and we can put eyes on Mars that are better than human eyes."
It is quite possible to transport astronauts to Mars within six months. Shannon Lucid was able to walk without help when she returned to Earth from a 6-month stay on Mir. It is true that being able to walk and being able to explore are two different things, and it is also true that not all cosmonauts and astronauts were able to walk immediately after returning from long stays on Mir. However, martian gravity is approximately two-fifths that of Earth, making the acclimation a bit easier. Also, it is likely that a human crew would stay on the martian surface for about a year -- plenty of time to get acclimated and get a lot of exploring done.
Tele-robots will be very useful in the exploration of Mars. They will be able to sense things differently, and in some ways in more detail, than humans. Dr. Park pointed this out, with his use of the words "sight," "touch" and "smell." However, a few comparisons between human and robotic missions demonstrate that robots are not a substitute for human explorers.
During the Mars Pathfinder mission, the Sojourner rover was "active for more than 80 days on the surface". It traveled "over 100 meters" total and "never strayed more than 12 meters from the lander". It did not return any soil or rocks from Mars. (
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Compare these figures with the Apollo 17 mission, where the astronauts traversed 35 kilometers of the moon's surface in only a little over three days (75 hours) and returned 110 kilograms of moon rocks. (www.nasm.edu/apollo) In other words, the human explorers of Apollo 17 traveled approximately 350 times the distance Sojourner traveled, and their length of stay was only one-twentieth that of Sojourner. They also collected 1,000 times more material than the Sample Return Mission will.
One can argue that it is much more difficult to travel to Mars and collect martian soil and rock samples than it is to travel to the moon and collect lunar samples. This is precisely why we need human explorers. Noting the recent failure and possible crash of Mars Polar Lander, one cannot help but be reminded of Neil Armstrong's lunar landing on Apollo 11. The lunar lander's computer was suggesting landing in an unsafe area filled with boulders and craters. Armstrong saw this and manually piloted the lander to a safe place.
Had a computer been the only pilot on-board Apollo 11, the lander would have crashed. Robots do not have the ability to analyze and adapt to unknown situations the way that people do. With a communications time delay of 8 to 20 minutes each way, martian exploration will need people who can assess an unknown and potentially dangerous situation and act without having to wait for commands from Earth.
It is true that human explorers cost more to transport and maintain than tele-robots. I will also admit that advancements in artificial intelligence could improve a robot's performance and capability to adapt to adverse situations. However, thus far, I've only mentioned practical comparisons of performance and considerations of cost.
The most important component of space exploration cannot be measured by tax dollars. It is not scientific and cannot be analyzed with charts and graphs. It is the human component.
Put simply, robots cannot take "giant leaps for mankind." While it is true that Pathfinder was popular, a person walking around on the martian surface would be much more inspirational. If you are old enough to remember, try to compare what you felt watching Neil Armstrong and Buzz Aldrin walking on the moon to what you felt seeing the pictures of Pathfinder on Mars. I've been told that in the first few seconds that Neil Armstrong could be seen standing on the moon, anyone around the world who had a television could watch this person from Earth walking on another celestial body and feel as though they were there with him. We cannot relate to robots in this way.
Robots cannot tell us how it feels to look up and see Earth as just a dot in the sky. Robots cannot shed tears at the beauty of a martian sunrise. Robots cannot understand the meaning and consequences of finding evidence of life on another planet. Robots do not have souls.
The nearly impossible work that the people at Jet Propulsion Laboratory do every day is impressive and necessary, and should be recognized and commended more often. Robotic exploration is a necessary precursor to human exploration, and robots will be a great help to human explorers on the surface of Mars. But robots, even if operated from Earth by people, are no substitute for human explorers.
Jenny R. Gruber
Rhodes Scholar
Research student, Engineering Science
University College
Oxford University
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