In the boardrooms, laboratories and command centres of space agencies around the world a war is coming — a war, which will pit burley astronauts, who excel at winning the hearts and minds of the space-exploration funding taxpayers, against the metallic reason and spider-like appendages of space probes, and their bespectacled, and pocket protected creators.
Since Laika — the stray dog sent into orbit by the Russians who proved a living thing could survive in zero G — gained the auspicious honour of being the first living creature to orbit our planet, humankind has made more and more inroads into space. From Yuri Gagarin, the first person in space, to Neil Armstrong, the first earthling to set foot on another planetoid, human spaceflight has stirred the passions of the world with romantic images and speeches. But despite this, the workhorse of space exploration has always been, up to this point, the cheap and expendable unmanned space probe.
With multi-billion dollar proposals to send people to Mars, and a scheduled return to the moon, the question of whether the cost-to-discovery ratio of manned missions — which is significantly lower than that of probes — is justifiable is starting to be asked more and more often by scientists, politicians, taxpayers and journalists.
Impact of human space exploration
In 1961 Yuri Gagarin became the first person to orbit our planet. His trip was but the tip of the iceberg, kicking off almost 50 years of human spaceflight, whose crowning achievement, it could be argued, was landing people on the moon. But, scientifically speaking, what was accomplished by the Apollo missions?
A Smithsonian Institution website lists the 10 most important scientific discoveries of the Apollo missions. All are geological in nature, revealing truths about the composition and formation of the Earth and the moon. But none required a human hand to be completed.
While the Apollo program, which landed astronauts on the moon six times between 1969 and 1972, costing an estimated US$25 billion, required massive scientific and technological leaps, none of the 10 most important discoveries listed by the Smithsonian would be out of the reach of an unmanned probe, such as a Mars rover. Ironically, as it turns out, the most significant scientific contribution of the Apollo program might not have had anything to do with the moon.
A Journal of Nature poll conducted earlier this year asked 800 active scientists, who had published in the past three years, about the impact Apollo had on their lives. Half of the respondents said that the program directly inspired them to choose science as a career, and 90 per cent felt that human spaceflight would inspire the next generation of scientists. However, paradoxically, 80 per cent favoured shifting funds from human exploration to unmanned missions.
Why would people, whose lives were shaped by humans walking on the moon, feel that unmanned missions should take priority over human exploration? Perhaps a look at the Voyager missions will help answer that question.
Voyager 1 and 2
In the mid-1960s NASA presented an ambitious proposal to its funding committees. Taking advantage of a “once every 175 years” planetary alignment of Jupiter, Saturn, Uranus and Neptune, NASA would send four probes to explore the outer planets of our solar system.
At the time, most of the knowledge of the outer planets had come from earth-bound observation with telescopes. NASA saw an opportunity to greatly add to that knowledge and was subsequently given the green light for the project.
However the Voyager project soon ran into funding conflicts, with Nixon unwilling to pay for both the Mariner-Jupiter-Saturn-1977 (MJS-77) project — as Voyager was originally named — and the space shuttle. Fearing a complete cancellation the MJS-77 team proposed a significantly paired down mission, utilizing only two probes, Voyager 1 and 2.
Launched in 1977, at a cost of US$865 million — or less than four per cent of the Apollo budget — the Voyager 1 and 2 probes were sent toward Jupiter in a staggered fashion, allowing Voyager 2 to take over for Voyager 1, should some sort of malfunction occur.
The Voyager 1 and 2 probes had three computers, each with a memory capacity totaling 8,000 words. This small amount of memory meant that for each phase of the mission the controllers on earth would have to delete the old code for the previous mission and upload a new set of instructions. This also allowed the controllers to change and expand the mission as they saw fit.
Voyager 1 reached Jupiter in march of 1979, and began transmitting our first close-up photographs of an outer planet back to earth, along with vast amounts of data on things such as the planet’s electromagnetic field and atmospheric composition and the active volcanoes on the moon Io. It was joined by the Voyager 2 probe in June. Both probes then proceeded to Saturn where they continued to expand our knowledge of the solar system, including information on Titan, a moon of Saturn, which was thought to contain liquid water.
At Saturn, the probes went their separate ways, with Voyager 2 continuing on to Uranus and Neptune, while Voyager 1 headed north, above the plane of our solar system.
The Voyager probes are still active and send back data to this day, and although they were only designed to last five years, current estimates predict that the probes will continue to function until the mid-2020s, when their batteries will finally run out. The probes, which already have many “firsts” to their credit, and exponentially expanded our knowledge of the outer planets, are set to make a final “first” in 2014, when they will completely exit our solar system, becoming the Earth’s first interstellar probes.
Probe versus Person
Given the multitude of things we have learned from just two of the hundreds of space probes we have sent into the stars, it becomes hard to argue for human space exploration. Even more so when you consider that, for the cost of Apollo (US$25 billion), more than 50 Voyager-type probes could have been launched. Even NASA’a current crop of superstar probes, the Mars rovers — which, like the Voyager probes have performed beyond their mission specifications, cost less than US$1 billion, or 1/450th of the current projected cost to send human beings there. Furthermore, in addition to the monetary cost, there is the human cost to factor in.
In an article titled “How to get humans to Mars: make it a one way trip,” Phillip Yam, of Scientific American, points out that one of the most daunting technological challenges of a manned mars mission wouldn’t be getting there, or landing, or navigation, but ensuring that the astronauts stay alive for the duration of the journey.
Our planet does many things for us. Its gravity keeps us grounded, its atmosphere lets us breathe and its magnetic field prevents our DNA from being “torn to pieces” by cosmic rays. However, once we leave the earth’s protective barriers, we expose ourselves to those energetic particles given off by the sun.
Exposure to cosmic rays was not an issue for the Apollo crews, as there were very few major solar particle events — the source of cosmic rays — during their trips. However the trip to and from the moon was relatively short — lasting just over eight days — compared to the 6-12 months projected for a mission to mars, during which time several solar particle events could occur.
Regardless of the cost or the danger, it is impossible to deny, as was illustrated by Journal of Nature’s poll, that human space flight has the ability to inspire great things in others. Despite their long lists of “firsts” and discoveries, unmanned probes cannot duplicate that excitement.
Before writing off manned space travel we must ask ourselves, if we had never sent astronauts to the moon, would anyone have cared enough to fund the Voyager project?
(See pg. 8, “The need to continue
our journey into space,” for a comment about human space travel.)