Nuclear
All Nuclear power energy is derived from converting Mass into Energy using Einstein's famous equation E=mc2
There are two types of Nuclear power, Fission and Fusion, both can be used for space propulsion systems, and energy sources.
Interplanetary Nuclear Fusion Rockets, A Mini-Documentary | AsteronX
Fusion is when two atoms are combined this is the reaction that our Sun (Sol) uses. Due to the high temperatures and pressures we have so far not been able to use this method of Nuclear energy except for making hydrogen bombs that currently require a Fission Nuclear Bomb to start the Fusion reaction although there some very promising research.
Fission (Splitting the Atom) releases energy from the use of the atomicly heavy isotopes of Uranium or Plutonium.
We have successfully used fission
The main problem for using Fission is controlling the radioactivity that cannot be converted to energy, unlike fusion the radioactive particles give off by splitting atoms have very long half lives(radioactive decay), this is less of an issue in space as our Sun also generates a lot of radiation so as long as any crew or sensitive cargo is shielded correctly this form of nuclear energy can be used, for example the Voyager probes used a radioisotope nuclear power source.
Nuclear fission rockets and spacecraft(See British Project Orion) were successfully been designed in the 1960s
1967 Nuclear fission propulsion - working design YouTube
Full Nuclear fission designs have not been used for political reasons like the SALT2 treaty and partly due to safety issues, as if a nuclear generator was to be destroyed in the atmosphere during launch, this has not stopped the use of safer fission radioisotope power supplies for probes going to deep space missions where solar panels would have problems.
Meanwhile more research is still being made as most likely some form of nuclear power supply will be need for early manned Mars missions.
Russia
RD-0410
This was a Soviet nuclear thermal rocket engine developed from 1965 through the 1980s using liquid hydrogen propellant. The engine was ground-tested at the Semipalatinsk Test Site, and its use was incorporated in the Kurchatov Mars 1994 manned mission proposal.
The RD-0410 was "the only operational nuclear engine in the USSR". First flight 1985.
It had a Specific impulse of 910 s and a Burn time of 3,600 s.
There were three nuclear thermal rocket engine models - RD-0411, -0412, and -0413 (also known as RO-31/41/51). The engine was designed in the early 1970s, using experience gained from the RD-0410 project. The RD-0413 Engine was designed in the early 1980s, as a cheap upgrade to the RD-0411 engine.
But the Soviet Union imploded during the 1980s, development slowed, then halted completely by 1994.
TEM Russian nuclear engine
Russian nuclear rocket engine may get mankind to other planets
Update 3 March 2016 from Sputnik News
The nuclear engine currently being developed in Russia by the nuclear agency Rosatom and the Russian Federal Space Agency (Roscosmos) will allow a spaceship to reach Mars in an unprecedentedly short period of just 1.5 months, Rosatom's General Director Sergei Kirienko said Wednesday.
According to Kirienko, using existing technology, a spacecraft takes around 18 months to reach Mars and it has no way of returning back to Earth or to maneuver while en route.
"Installing a nuclear engine will allow [a spacecraft] to fly to Mars in a month and a half and to come back, as the spacecraft would retain the ability to maneuver," Kirienko said, addressing the Federation Council.
Moscow is a world leader in the sphere of atomic energy. At the moment, Rosatom, which incorporates many enterprises and nuclear institutions, is constructing 41 nuclear reactors, of which 34 are abroad.
Published: 28 January, 2010, 10:37
Humans on Mars and beyond and protecting the Earth from asteroids… A new nuclear propulsion system to be used in spacecrafts is set to be developed in Russia.
The technology will allow bigger vehicles to be sent into space, making manned missions to Mars possible. It will also mean new and more efficient type of satellites to monitor weather and gather intelligence.
“It’s a kind of inter-orbital tow spacecraft for launching new heavy satellites and spacecraft to far-destined orbits, as well as to the Moon and other planets in the Solar system. At present we have rockets with chemical fuel that can launch a vehicle weighing 5-6 tonnes. While these new vehicles will weigh two, or even four times more,” explained Igor Afanasyev from Cosmonautics News Magazine.
The Kremlin has set aside some 17 billion rubles to help develop a nuclear-powered rocket engine. 500 million rubles of that money are set aside for 2010.
Russia's space company Energia, which helps to develop the engine, estimates the new spacecraft could be tested by 2015.
Currently rockets use solid or liquid fuel boosters, which are very energy-inefficient. With the new system, once the payload gets into space using conventional fuel, they can then stop using that booster and switch over to the new nuclear-powered drive that has the potential to bring payloads to much greater distances.
That is something that can help get payloads to the ISS, and this is even more important, as the US space shuttle program is going to end in 2010 and not resumed until 2015.
It also has implications for getting mankind even further to the Moon, possibly to Mars, and even exploration further in the cosmos.
This new technology also has potential applications for military defense. For instance it could be used to monitor troop movements in the field.
But what rocket and space corporation Energia is trying to really stress is the new system’s civil defensive potential.
“Some media outlets have misinterpreted our words on the application of the system – saying it might be used to propel a military spacecraft with offensive capabilities into space. In reality the system will help provide communications in regions hit by natural disasters and military conflicts. It will also be used to avert an asteroid threat and to monitor our territories,” Energia’s statement says.
Russia has successfully built a nuclear powered rocket engine that is used on its 9M730 Burevestnik intercontinental cruise missile.
USA
NASA Nuclear propulsion
NASA has looked into many Nuclear propulsion systems over the years, especially between 1955 and 1972 including tests on fully working systems with 17 hours of run time.
Work since has been very intermittent in 2013 a Marshall Space Flight Center reference work looked at developing a Nuclear Cryogenic Propulsion Stage.
One proposal was a Bimodal Nuclear Thermal Rocket (artistic rendering)
Currently some work is being done on looking into Fusion based systems, but not with any solid commitment on behalf of NASA.
Nuclear Thermal Rocket
The air enhanced nuclear thermal turbo rocket can have an ISP of 1663. This is five times better than a chemical rocket and almost double the nuclear thermal rockets tested in the 1960s.
An air breathing chemical rocket could get to an ISP of 3600 while in the atmosphere.
DRACO
Since 2023 NASA and DARPA have started on the Demonstration Rocket for Agile Cislunar Operations (DRACO) program that aims to launch in 2027.
How Nuclear rockets will get us to Mars and beyond
Nuclear power plants
One exciting development in this field id NASA and DoE to test and produce a new kilowatt reactor for space purposes for powering satellites, planetary exploration probes and rovers to support for Mars habitats and Mars chemical production.
Another Small Reactor for Deep Space Exploration by Los Alamos National Lab