While the former Soviet Union released over thirty nuclear reactors into space , the United States have only used this system in a single mission (that we know, of course). With a mass of 290 kg, the SNAP-10A had a thermal power of 30 kW, although only 500 W of electricity generated. It was released in 1965 and became the first and last U.S. space nuclear reactor.
SNAP-10A: officially, the only U.S. nuclear reactor in space (NASA).
Since then, NASA has chosen the radioisotope generators (RTG) when electricity supply the spacecraft could not use solar panels (Viking, Pioneer 10 and 11, Voyager 1 and 2, Galileo, Cassini, New Horizons or Curiosity). In fact, technological advances in the field of photovoltaic panels has allowed its use in missions to the outer planets, as is the case with Juno . So "NASA has decided to forget about nuclear reactors in space? Well apparently not, at least not on paper. In fact, the space agency made last year a study to demonstrate the feasibility of a small nuclear reactor to power a large class ships Flagship (with a value higher than 2500 million dollars) traveling beyond the orbit of Mars.
What are the advantages of nuclear reactors against radioisotope generators? Several, see what they are. The RTGs use plutonium-238 from Russia, but the reserves available for NASA missions are diminishing rapidly. The agency has launched several programs to develop more advanced RTGs type Stirling (ASRG) , more efficient, yet very little plutonium is available for the missions of the next decade. Although the Department of Energy (DOE) plans to produce plutonium-238 back in 2016 at a rate of about 2 kg per year, the subject of Reservations Plutonium-238 is still a very sensitive issue that threatens to paralyze the outer Solar System exploration. A nuclear reactor could easily supply more than 1 kW of power required by the probes without the need for Flagship plutonium. As for security, remember that a nuclear reactor is not tripped no danger of any radiation, unlike plutonium-238, which is highly radioactive and toxic. That is, a spacecraft with a nuclear reactor is safer from the environmental point of view that RTGs equipped.
comparison chart of different space reactors.
According to the NASA study, the reactor of 1 kW of electrical power would have a size of 4.5 meters in diameter once deployed radiators and emit a radiation dose of 25 krad at most, which would allow the use commercial electronics on the ship. It would be a fast neutron reactor, ie, fuel use highly enriched in uranium-235. This type of reactor can reduce the amount of moderator used in the structure and minimize their total mass.
Reactor BES-5 Buk (Kosmonavtiki Novosti.)
The fuel would be a U-Mo alloy to 10% (10% uranium by weight of molybdenum) and use a reflector of beryllium oxide (BeO), an anti-radiation shield of tungsten and lithium hydride. As coolant would be used an alloy of sodium and potassium (NaK) that maintain the core temperature below 1200 K. To generate electricity would be used a thermoelectric system. As a control bar, there would be a central element boron carbide. The bar would be removed once in orbit to activate the reactor and ensure optimal criticality over time. The mass of the reactor would be 133-159 kg, although the installation would have a total mass of 600-770 kg. Would be located about ten meters from the rest of the ship to minimize the radiation dose and the mass of the structure of sepración. In short, some characteristics similar to the reactors Buk (BES-5) Soviet the SNAP-100A.
reactor details of NASA (NASA).
Details Core (NASA).
features reactor (NASA).
Budget Project (NASA).
This reactor could serve a new generation of probes to explore outer solar system, such as JEO mission (Jupiter-Europa Orbiter). This small nuclear reactor could also serve as a basis for developing electric propulsion systems. Unfortunately, last week we learned of the sad state exploration program at NASA's unmanned , so the possibility of developing a reactor of this type is, at present, rather small.
Tube Europe with a nuclear reactor (NASA).
References:
SNAP-10A: officially, the only U.S. nuclear reactor in space (NASA).
Since then, NASA has chosen the radioisotope generators (RTG) when electricity supply the spacecraft could not use solar panels (Viking, Pioneer 10 and 11, Voyager 1 and 2, Galileo, Cassini, New Horizons or Curiosity). In fact, technological advances in the field of photovoltaic panels has allowed its use in missions to the outer planets, as is the case with Juno . So "NASA has decided to forget about nuclear reactors in space? Well apparently not, at least not on paper. In fact, the space agency made last year a study to demonstrate the feasibility of a small nuclear reactor to power a large class ships Flagship (with a value higher than 2500 million dollars) traveling beyond the orbit of Mars.
What are the advantages of nuclear reactors against radioisotope generators? Several, see what they are. The RTGs use plutonium-238 from Russia, but the reserves available for NASA missions are diminishing rapidly. The agency has launched several programs to develop more advanced RTGs type Stirling (ASRG) , more efficient, yet very little plutonium is available for the missions of the next decade. Although the Department of Energy (DOE) plans to produce plutonium-238 back in 2016 at a rate of about 2 kg per year, the subject of Reservations Plutonium-238 is still a very sensitive issue that threatens to paralyze the outer Solar System exploration. A nuclear reactor could easily supply more than 1 kW of power required by the probes without the need for Flagship plutonium. As for security, remember that a nuclear reactor is not tripped no danger of any radiation, unlike plutonium-238, which is highly radioactive and toxic. That is, a spacecraft with a nuclear reactor is safer from the environmental point of view that RTGs equipped.
comparison chart of different space reactors.
According to the NASA study, the reactor of 1 kW of electrical power would have a size of 4.5 meters in diameter once deployed radiators and emit a radiation dose of 25 krad at most, which would allow the use commercial electronics on the ship. It would be a fast neutron reactor, ie, fuel use highly enriched in uranium-235. This type of reactor can reduce the amount of moderator used in the structure and minimize their total mass.
Reactor BES-5 Buk (Kosmonavtiki Novosti.)
The fuel would be a U-Mo alloy to 10% (10% uranium by weight of molybdenum) and use a reflector of beryllium oxide (BeO), an anti-radiation shield of tungsten and lithium hydride. As coolant would be used an alloy of sodium and potassium (NaK) that maintain the core temperature below 1200 K. To generate electricity would be used a thermoelectric system. As a control bar, there would be a central element boron carbide. The bar would be removed once in orbit to activate the reactor and ensure optimal criticality over time. The mass of the reactor would be 133-159 kg, although the installation would have a total mass of 600-770 kg. Would be located about ten meters from the rest of the ship to minimize the radiation dose and the mass of the structure of sepración. In short, some characteristics similar to the reactors Buk (BES-5) Soviet the SNAP-100A.
reactor details of NASA (NASA).
Details Core (NASA).
features reactor (NASA).
Budget Project (NASA).
This reactor could serve a new generation of probes to explore outer solar system, such as JEO mission (Jupiter-Europa Orbiter). This small nuclear reactor could also serve as a basis for developing electric propulsion systems. Unfortunately, last week we learned of the sad state exploration program at NASA's unmanned , so the possibility of developing a reactor of this type is, at present, rather small.
Tube Europe with a nuclear reactor (NASA).
References:
- Small Fission Power System Feasibility Study Final Report (NASA, November 18, 2010).
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