Interplanetary spaceflight or interplanetary travel is the crewed or uncrewed travel between stars and planets,usually within a single planetary system. In practice,spaceflights of this type are confined to travel between the planets of the Solar System. Uncrewed space probes have flown to all the observed planets in the Solar System as well as to dwarf planets Pluto and Ceres,and several asteroids. Orbiters and landers return more information than fly-by missions. Crewed flights have landed on the Moon and have been planned,from time to time,for Mars,Venus and Mercury. While many scientists appreciate the knowledge value that uncrewed flights provide,the value of crewed missions is more controversial. Science fiction writers propose a number of benefits,including the mining of asteroids,access to solar power,and room for colonization in the event of an Earth catastrophe.
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
A monopropellant rocket is a rocket that uses a single chemical as its propellant. Monopropellant rockets are commonly used as small attitude and trajectory control rockets in satellites,rocket upper stages,manned spacecraft,and spaceplanes.
A nuclear thermal rocket (NTR) is a type of thermal rocket where the heat from a nuclear reaction replaces the chemical energy of the propellants in a chemical rocket. In an NTR,a working fluid,usually liquid hydrogen,is heated to a high temperature in a nuclear reactor and then expands through a rocket nozzle to create thrust. The external nuclear heat source theoretically allows a higher effective exhaust velocity and is expected to double or triple payload capacity compared to chemical propellants that store energy internally.
A nuclear electric rocket is a type of spacecraft propulsion system where thermal energy from a nuclear reactor is converted to electrical energy,which is used to drive an ion thruster or other electrical spacecraft propulsion technology. The nuclear electric rocket terminology is slightly inconsistent,as technically the "rocket" part of the propulsion system is non-nuclear and could also be driven by solar panels. This is in contrast with a nuclear thermal rocket,which directly uses reactor heat to add energy to a working fluid,which is then expelled out of a rocket nozzle.
The nuclear salt-water rocket (NSWR) is a theoretical type of nuclear thermal rocket designed by Robert Zubrin. In place of traditional chemical propellant,such as that in a chemical rocket,the rocket would be fueled by salts of plutonium or 20-percent-enriched uranium. The solution would be contained in a bundle of pipes coated in boron carbide. Through a combination of the coating and space between the pipes,the contents would not reach critical mass until the solution is pumped into a reaction chamber,thus reaching a critical mass,and being expelled through a nozzle to generate thrust.
Beam-powered propulsion,also known as directed energy propulsion,is a class of aircraft or spacecraft propulsion that uses energy beamed to the spacecraft from a remote power plant to provide energy. The beam is typically either a microwave or a laser beam,and it is either pulsed or continuous. A continuous beam lends itself to thermal rockets,photonic thrusters,and light sails. In contrast,a pulsed beam lends itself to ablative thrusters and pulse detonation engines.
The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is an electrothermal thruster under development for possible use in spacecraft propulsion. It uses radio waves to ionize and heat an inert propellant,forming a plasma,then a magnetic field to confine and accelerate the expanding plasma,generating thrust. It is a plasma propulsion engine,one of several types of spacecraft electric propulsion systems.
A solar thermal rocket is a theoretical spacecraft propulsion system that would make use of solar power to directly heat reaction mass,and therefore would not require an electrical generator,like most other forms of solar-powered propulsion do. The rocket would only have to carry the means of capturing solar energy,such as concentrators and mirrors. The heated propellant would be fed through a conventional rocket nozzle to produce thrust. Its engine thrust would be directly related to the surface area of the solar collector and to the local intensity of the solar radiation.
Nuclear propulsion includes a wide variety of propulsion methods that use some form of nuclear reaction as their primary power source. The idea of using nuclear material for propulsion dates back to the beginning of the 20th century. In 1903 it was hypothesized that radioactive material,radium,might be a suitable fuel for engines to propel cars,planes,and boats. H. G. Wells picked up this idea in his 1914 fiction work The World Set Free. Many aircraft carriers and submarines currently use uranium fueled nuclear reactors that can provide propulsion for long periods without refueling. There are also applications in the space sector with nuclear thermal and nuclear electric engines which could be more efficient than conventional rocket engines.
Project Prometheus was established in 2003 by NASA to develop nuclear-powered systems for long-duration space missions. This was NASA's first serious foray into nuclear spacecraft propulsion since the cancellation of the SNTP project in 1995. The project was planned to design,develop,and fly multiple deep space missions to the outer planets.
The Nuclear Engine for Rocket Vehicle Application was a nuclear thermal rocket engine development program that ran for roughly two decades. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". It was a joint effort of the Atomic Energy Commission (AEC) and the National Aeronautics and Space Administration (NASA),and was managed by the Space Nuclear Propulsion Office (SNPO) until the program ended in January 1973. SNPO was led by NASA's Harold Finger and AEC's Milton Klein.
Solar electric propulsion (SEP) refers to the combination of solar cells and electric thrusters to propel a spacecraft through outer space. This technology has been exploited in a variety of spacecraft designs by the European Space Agency (ESA),the JAXA,Indian Space Research Organisation (ISRO) and NASA. SEP has a significantly higher specific impulse than chemical rocket propulsion,thus requiring less propellant mass to be launched with a spacecraft. The technology has been evaluated for missions to Mars.
Spacecraft electric propulsion is a type of spacecraft propulsion technique that uses electrostatic or electromagnetic fields to accelerate mass to high speed and thus generating thrust to modify the velocity of a spacecraft in orbit. The propulsion system is controlled by power electronics.
RD-0410 was a Soviet nuclear thermal rocket engine developed by the Chemical Automatics Design Bureau in Voronezh 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 crewed mission proposal.
An orbital propellant depot is a cache of propellant that is placed in orbit around Earth or another body to allow spacecraft or the transfer stage of the spacecraft to be fueled in space. It is one of the types of space resource depots that have been proposed for enabling infrastructure-based space exploration. Many depot concepts exist depending on the type of fuel to be supplied,location,or type of depot which may also include a propellant tanker that delivers a single load to a spacecraft at a specified orbital location and then departs. In-space fuel depots are not necessarily located near or at a space station.
Project Rover was a United States project to develop a nuclear-thermal rocket that ran from 1955 to 1973 at the Los Alamos Scientific Laboratory (LASL). It began as a United States Air Force project to develop a nuclear-powered upper stage for an intercontinental ballistic missile (ICBM). The project was transferred to NASA in 1958 after the Sputnik crisis triggered the Space Race. It was managed by the Space Nuclear Propulsion Office (SNPO),a joint agency of the Atomic Energy Commission (AEC),and NASA. Project Rover became part of NASA's Nuclear Engine for Rocket Vehicle Application (NERVA) project and henceforth dealt with the research into nuclear rocket reactor design,while NERVA involved the overall development and deployment of nuclear rocket engines,and the planning for space missions.
Rocket propellant is used as reaction mass ejected from a rocket engine to produce thrust. The energy required can either come from the propellants themselves,as with a chemical rocket,or from an external source,as with ion engines.
A thermal rocket is a rocket engine that uses a propellant that is externally heated before being passed through a nozzle to produce thrust,as opposed to being internally heated by a redox (combustion) reaction as in a chemical rocket.
Blue Moon is a family of lunar landers and their associated infrastructure,intended to carry humans and cargo to the Moon,under development by a consortium led by Blue Origin and including Lockheed Martin,Draper,Boeing,Astrobotic,and Honeybee Robotics. Two versions of Blue Moon are under development:a robotic lander planned to land on the Moon in 2024,and a larger human lander planned to land a crew of four astronauts on the lunar surface for the NASA Artemis V mission in 2029.
