“I will say, categorically, we cannot effectively explore space without nuclear power and, in the longer run, nuclear propulsion,” NASA administrator Michael Griffin told the U.S. Congress in May 2005.
Since solar energy falls off with distance squared, exploration of the outer solar system and deep space will truly be possible only through nuclear technology, such as nuclear thermal propulsion or nuclear engine-powered rockets, explains Bruce Behrhorst, President of the Nuclear Space Technology Institute.
But whether through purposeful deception or simple ignorance, several vocal organizations are calling for a moratorium on the use of nuclear technology in space exploration. One such is the Global Network Against Weapons & Nuclear Power in Space, based in Gainesville, Florida and led by Bruce Gagnon. Gagnon claims that nuclear-powered rockets “are the foot in the door, the Trojan horse, if you will, for the militarization of space,” He sees their peaceful uses as a cover for the creation of space-based weapons.
Gagnon cites protection of astronauts from radiation as one of his main concerns. Ironically, astronauts tend to be the biggest supporters of nuclear-powered technology. Compared to onboard nuclear material, “the risk is much greater from the normal radiation environment from space-by orders of magnitude,” explains Roger Crouch, who was himself a space shuttle astronaut. In fact, in speaking of a possible human mission to Mars based on nuclear power, Crouch says that the increased speed would translate to reduced time spent in space, actually lowering radiation exposure and reducing health concerns.
Perhaps the public is starting to get the message. While hundreds protested at the launch in 1997 of the Cassini spacecraft to Saturn for its use of a nuclear power source, only a few dozen showed up on NASA’s doorstep at Cape Canaveral to protest New Horizons this year.
New Horizons was launched January 19 for its ten year, three-billion-mile voyage to the furthest reaches of the solar system, which are still in fact unexplored. It will become the first spacecraft to perform a flyby of Pluto, its moon Charon, and mysterious Kuiper Belt objects. Protesters fail to realize that getting to these distances requires nuclear technology.
Instead, behind most of the protests one tends to find a simple paranoia of the government and a general fear of science and technology. When faced with facts about the real risks involved, which are negligible, and the benefits of nuclear power, without which future exploration is nearly impossible, protesters can only imagine a giant conspiracy between scientist and legislator.
To dispel the most obvious fallacy, a spacecraft with onboard nuclear material is not equivalent to an out of control nuclear bomb. Nuclear technology in space is mostly comprised of a Radioisotope Thermoelectric Generator (RTG). The way an RTG generates electricity is different from a nuclear weapon; an RTG also uses plutonium-238-a non-fissionable atom-while a nuclear bomb uses highly enriched plutonium-239. Like all other radioactive atoms, plutonium-238 is unstable; it breaks apart after a specific amount of time. RTGs generate electricity by harnessing the energy of these spontaneous break-ups. Where the RTG and the bomb are similar is in their power potential. Scientists have calculated that a golf ball of plutonium is equivalent to the energy of 20,000 tons of TNT, allowing a few grams to power energy sources in space instruments far, far away for a long, long time.
Legislative safeguards are also in place. The U.N. Convention on International Liability for Damage Caused by Space Objects forces RTG units to be adequately shielded to ensure that in the event of an explosion or impact, vaporization would be prevented. Non-nuclear proliferation policies signed by Canada and European countries disallow them from putting most nuclear material in space, while the United Nations Committee on the Peaceful Uses of Outer Space and the Outer Space Treaty of 1967, signed by 91 countries, forbids weapons of mass destruction in space. Even the organization People Against Weapons in Space, which opposed Canadian involvement in the Ballistic Missile Defense program, issued a statement recognizing that RTGs are not weapons.
Many special mission safeguards, as well as special process and procedure requirements, such as product reliability, quality assurance and tireless testing, are put in place whenever a spacecraft contains nuclear material, said Leopold Summerer of the European Space Agency’s Advanced Concepts Team, and member of the International Astronautical Federation.
Summerer also affirms the staggering benefit to risk ratio in nuclear-powered spacecraft. NASA’s Project Prometheus is an example. Though now cancelled, Prometheus was set to develop nuclear reactors on the order of 100-200 kilowatts, about a thousand times more powerful than current RTGs, for further in the future deep space missions.
All is not lost. Prometheus technology may be rerouted towards the development of small nuclear reactors to power lunar outposts. According to John Logsdon, director of the Space Policy Institute, nuclear power would play an important role in returning humans to the moon. NASA administrator Griffin is in fact requesting assistance from other nations, including France and Japan, in providing the reactor. Considering the main reason for opposing nuclear power in space tends to be the inevitable weapons arms race they are imaged to engender, the reality is that such a complicated technology actually forces nuclear countries to cooperate, the usual by-product of space exploration in general.
Near-future space exploration will continue to owe its ever more advanced capabilities to nuclear technology. With six wheels, over twice the size and ten times the payload of the current Mars Rovers, the Mars Science Laboratory-touted as NASA’s 2009 “extraterrestrial SUV”-will be made possible through a next generation Multi-Mission RTG. Picking up where Viking left off, its ultimate goal is to analyze soil scooped from the surface and drilled from rocks and to search for the building blocks of life, while recording daily atmospheric conditions. Put simply, you cannot run a wide-roaming science SUV on solar panels alone.
In ten years time New Horizons will arrive at the planet which lent its name to the now controversial radioactive element powering its core. In the intervening time, many new spacecraft bearing radioactive fuel are set to launch as the exploration of the solar system continues. It is public fear, and not the myriad technical issues often cited as reasons for this fear, may be the decisive factor in deciding whether this necessary technological development, and the scientific progress which it engender, will be allowed to continue.
