Project Longshot was a conceptual interstellar spacecraft design. It would have been an uncrewed

starship A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for interstellar travel, traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" appears as early as 188 ...

(about 400 tonnes), intended to fly to and enter orbit around

Alpha Centauri B Alpha Centauri ( Latinized from α Centauri and often abbreviated Alpha Cen or α Cen) is a triple star system in the constellation of Centaurus. It consists of 3 stars: Alpha Centauri A (officially Rigil Kentaurus), Alpha Centaur ...

nuclear pulse propulsion Nuclear pulse propulsion or external pulsed plasma propulsion is a hypothetical method of spacecraft propulsion that uses nuclear explosions for thrust. It originated as Project ''Orion'' with support from DARPA, after a suggestion by Stanislaw ...

History

Developed by the

US Naval Academy The United States Naval Academy (US Naval Academy, USNA, or Navy) is a federal service academy in Annapolis, Maryland. It was established on 10 October 1845 during the tenure of George Bancroft as Secretary of the Navy. The Naval Academy is ...

and

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

, from 1987 to 1988, Longshot was designed to be built at Space Station ''Freedom'', the precursor to the existing

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...

. Similar to

Project Daedalus Project Daedalus (named after Daedalus, the Greek mythological designer who crafted wings for human flight) was a study conducted between 1973 and 1978 by the British Interplanetary Society to design a plausible uncrewed interstellar probe.Proj ...

, Longshot was designed with existing technology in mind, although some development would have been required; for example, the Project Longshot concept assumes "a three-order-of-magnitude leap over current propulsion technology".

Mission

Unlike Daedalus, which used an open-cycle fusion engine, Longshot would use a long-lived

nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radio ...

reactor for power. Initially generating 300 kilowatts, the reactor would power a number of

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...

s in the engine that would be used to ignite

inertial confinement fusion Inertial confinement fusion (ICF) is a fusion energy process that initiates nuclear fusion reactions by compressing and heating targets filled with thermonuclear fuel. In modern machines, the targets are small spherical pellets about the size of ...

similar to that in Daedalus. The main design difference is that Daedalus also relied on the

fusion reaction Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifeste ...

to power the ship, whereas in the Longshot design the internal reactor would provide this power. The reactor would also be used to power a laser for communications back to Earth, with a maximum power of 250 kW. For most of the journey, this would be used at a much lower power for sending data about the

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

; but during the flyby, the main engine section would be discarded and the entire power capacity dedicated to communications at about 1 kilobit per second. Longshot would have a mass of at the start of the mission including 264 tonnes of

helium-3 Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron (the most common isotope, helium-4, having two protons and two neutrons in contrast). Other than protium (ordinary hydrogen), helium-3 is the ...

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two Stable isotope ratio, stable isotopes of hydrogen (the other being Hydrogen atom, protium, or hydrogen-1). The atomic nucleus, nucleus of a deuterium ato ...

pellet fuel/propellant. The active mission payload, which includes the

fission reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from ...

but not the discarded main propulsion section, would have a mass of around 30 tonnes. A difference in the mission architecture between Longshot and the Daedalus study is that Longshot would go into orbit about the target star while the higher speed Daedalus would do a one shot fly-by lasting a comparatively short time.

References

Bibliography

Beals, K. A., M. Beaulieu, F. J. Dembia, J. Kerstiens, D. L. Kramer, J. R. West and J. A. Zito
''Project Longshot: An Unmanned Probe To Alpha Centauri.''
U S Naval Academy. NASA-CR-184718. 1988.

External links

(This article refers to an Alpha and Beta Centauri as the orbital target of the mission, but the correct nomenclature for these two components of the Alpha Centauri binary star system is Alpha Centauri A and B.

Beta Centauri Beta Centauri is a triple star system in the southern constellation of Centaurus. It is officially called Hadar (). The Bayer designation of Beta Centauri is Latinised from β Centauri, and abbreviated Beta Cen or β Cen. The sys ...

is an entirely different, unassociated star.) {{Nuclear propulsion Hypothetical spacecraft Longshot Interstellar travel NASA programs United States Naval Academy Alpha Centauri 1987 in science 1988 in science

History

Mission

See also

References

Bibliography

External links