Helios (propulsion system)
Encyclopedia
Helios is a design for a spacecraft propulsion system such that small (0.1 kiloton) nuclear bombs
would be detonated in a chamber roughly 130 feet in diameter. Water would be injected into the chamber, super-heated by the explosion and expelled for thrust.
It was a precursor concept to the Orion project
. Like Orion, it would have achieved constant acceleration through rapid "pulsed" operation.
This design would have yielded a specific impulse
of about 1150 seconds (compared to a modern chemical rocket’s 450 seconds). However, a number of technical problems existed, most prominently how to keep the combustion chamber from exploding from the great pressures of the atomic detonations.
The Helios propulsion system was conceived originally by Freeman Dyson
.
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...
would be detonated in a chamber roughly 130 feet in diameter. Water would be injected into the chamber, super-heated by the explosion and expelled for thrust.
It was a precursor concept to the Orion project
Project Orion (nuclear propulsion)
Project Orion was a study of a spacecraft intended to be directly propelled by a series of explosions of atomic bombs behind the craft...
. Like Orion, it would have achieved constant acceleration through rapid "pulsed" operation.
This design would have yielded a specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
of about 1150 seconds (compared to a modern chemical rocket’s 450 seconds). However, a number of technical problems existed, most prominently how to keep the combustion chamber from exploding from the great pressures of the atomic detonations.
The Helios propulsion system was conceived originally by Freeman Dyson
Freeman Dyson
Freeman John Dyson FRS is a British-born American theoretical physicist and mathematician, famous for his work in quantum field theory, solid-state physics, astronomy and nuclear engineering. Dyson is a member of the Board of Sponsors of the Bulletin of the Atomic Scientists...
.
See also
- Project OrionProject Orion (nuclear propulsion)Project Orion was a study of a spacecraft intended to be directly propelled by a series of explosions of atomic bombs behind the craft...
(1958-1965), follow on to Helios using pusher-plate technology - Operation PlumbbobOperation PlumbbobOperation Plumbbob was a series of nuclear tests conducted between May 28 and October 7, 1957, at the Nevada Test Site, following Operation Redwing, and preceding Operation Hardtack I...
(1957), nuclear fission explosion test with steel plate experiment for Pascal-B
Further reading
- Project Orion: The True Story of the Atomic Spaceship By George Dyson (2003) (Google Books Link)