Is it worth the cost to continue sending humans into space when technology is advancing rapidly in robotics and unmanned “flight?” Robin McKie, writing for The Observer, presents an argument for the less popular automated future (2014). By centering the debate firmly around cost, the debate is framed as a return on investment in scientific knowledge and economic benefit.
The scientific argument for human-led missions is data collection rate and localized volume. Humans can simply outperform their robotic counterparts in mobility and environmental assessment with respect to time. A human can pick up and look for fossils in one hundred seashells on a planetary beach in the time a rover may examine only one. Further, some of those can be brought back with the human for more detailed analysis in the laboratories of earth, yielding even more scientific discovery. This last part about the return of humans is a key differentiator as the unmanned camp relies heavily on smaller, one-way vehicles that need not have any lift off capability from wherever they set down. Moreso, the human advocates argue that unmanned vehicles cannot discern the context of what they are surrounded by to look where experience, not programming, tells them to for a key discovery. In sum, citing Professor Ian Crawford of Birkbeck College, London, in the article:
“[The 1972 manned mission] Apollo 17 spent three days on the Moon while its astronauts made journeys across the lunar surface that totalled 31 kilometres…They also drilled a three-metre hole into the surface, the deepest made in an object outside Earth, left a range of instrument packages behind them, and then brought back a 76kg of rock back to Earth…[The 2004 Mars rover] Opportunity took 10 years before it managed to run up a travel total of 31km. More to the point, it returned no samples of any kind, did no drilling and returned only limited data.”
But, the unmanned proponents have the clear case of mission variety in their favor. With manned missions costing orders of magnitude greater than unmanned, the unmanned missions can launch to multiple locations not only on the same planet, but throughout the solar system as a whole. So, it is argued, that while science may lose a seashell on Mars, it has gained knowledge about multiple planetary moons, visited an asteroid or two, and captured imagery of Pluto. According to Martin Rees, Britain’s Astronomer Royal, “…the future of planetary exploration will continue to be dominated by robot probes which will be spread throughout the solar system. You can imagine robot fabricators mining the asteroids and building large structures in space or on the Moon.”
So, it seems that what is being argued is the depth of human exploration against the breadth of unmanned ventures. And who wins? As always, it depends. If the totality of scientific knowledge about our solar system is the goal, then the flooding of space with unmanned systems is the most cost effective method in the near term. But, there will be crossover point where we’ve been everywhere and it’s time to start digging deeper, literally. And, it will be at this critical juncture that the humans will again be able to argue a justification for their presence for scientific return on a costly investment.
So, in reality, both sides are right. Unmanned systems can saturate the cosmos and provide initial discoveries that greatly expand our knowledge of the universe around us. But, to truly understand the ecosystems we’ve discovered, either significant technological advances must be made or humans must be sent. This is a well-understood tradeoff between the two sides. Along, the way we must also continue to develop the technologies and experience that will allow the humans to explore when the time has come and they are needed, or can no longer sit idly by. Humans will long be reluctant to yield their exploratory nature to machines and be unable to resolve our fundamental desire to experience. Knowledge for the sake of knowledge has never been enough. Maritime chronometers were not invented to simply keep better time, they were invented to solve the longitude problem and safely send men to sea, far away from home. Similarly, scientific knowledge is not valuable unless it advances us as a civilization. We go to Mars to learn about Mars, but more intrinsically valuable, to find out if we can overcome the obstacles to cross that ocean of space and make that New World ours. That is a uniquely human endeavor and gives purpose to the unmanned missions. In a logical world, the robots win, but, the human spirit will not be denied and a cost benefit analysis will never satisfy the yearning of expansion.
McKie, R. (2014, December 06). Astronauts lift our spirits. But can we afford to send humans into space? Retrieved from https://www.theguardian.com/science/2014/dec/07/can-we-afford-to-send-humans-into-space