Interstellar probe
Encyclopedia
Space probe
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
that has left—or is expected to leave—the Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
and enter interstellar space
Interstellar medium
In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
, typically defined as the region beyond the heliopause. It also refers to probes capable of reaching star system
Star system
A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
s other than the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
's (capable of interstellar travel
Interstellar travel
Interstellar space travel is manned or unmanned travel between stars. The concept of interstellar travel in starships is a staple of science fiction. Interstellar travel is much more difficult than interplanetary travel. Intergalactic travel, or travel between different galaxies, is even more...
within a galaxy).
Interstellar Probe is also the name of a proposed NASA space probe intended to travel out 200 AU in 15 years, studied in 1999.
There are perhaps three areas to consider when examining interstellar probes: existing probes on interstellar trajectories (such as Voyager 1); plans for realistic interstellar probes (such as interstellar precursors); and more extraordinary plans using extreme cost, technology, or physics.
Even though termination shock happens as close as 80-100 AU, the maximum extent of influence of the Sun's gravitational field
Gravitational field
The gravitational field is a model used in physics to explain the existence of gravity. In its original concept, gravity was a force between point masses...
, the Hill/Roche sphere
Hill sphere
An astronomical body's Hill sphere is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit that lies within the planet's Hill sphere. That moon would, in turn, have a Hill sphere of its own...
, is 230,000 AU (1.1 pc). The nearest star system is Alpha Centauri
Alpha Centauri
Alpha Centauri is the brightest star in the southern constellation of Centaurus...
at 1.34 parsec (4.36 light years).
Existing interstellar probes
Five spacecraftSpacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
(three active spacecraft) are currently on interstellar trajectories:
Functional spacecraft
Voyager 1Voyager 1
The Voyager 1 spacecraft is a 722-kilogram space probe launched by NASA in 1977, to study the outer Solar System and eventually interstellar space. Operating for as of today , the spacecraft receives routine commands and transmits data back to the Deep Space Network. At a distance of as of...
(1977+)
In May 2005 a NASA press release expressed the consensus that Voyager 1 was now in the heliosheath. As of July 30, 2010, Voyager 1 is at a distance of around 10619000000 miles (17,089,581,460 km) or 114.24 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and traveling outward at roughly 3.6 AU per year (17 km/s). Scientists believe the craft will reach the heliopause in 2015.
Voyager 2
Voyager 2
The Voyager 2 spacecraft is a 722-kilogram space probe launched by NASA on August 20, 1977 to study the outer Solar System and eventually interstellar space...
(1977+)
Voyager 2 passed the termination shock into the heliosheath on October 30, 2007. Unlike Voyager 1, it has a working plasma science instrument, and is returning data on the temperature and pressure of this region. As of July 30, 2010, Voyager 2 is at a distance of around 8631000000 miles (13,890,213,540 km) or 93 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and traveling outward at roughly 3.263 AU per year (15.47 km/s) . Voyager 2 is expected to keep transmitting into the 2020s.
New Horizons
New Horizons
New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...
(2006+)
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, New Horizons is on an interstellar trajectory via Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
. By 2008 March 7, New Horizons was 9.37 AU from the Sun and traveling outward at 3.9 AU per year, however it will slow to an escape velocity of only 2.5 AU per year as it moves away from the Sun, so it will never catch up to either Voyager. As of early 2011, it was traveling at 3.356 AU/year (15.91 km/s) relative to the Sun.
Inactive missions
Pioneer 10Pioneer 10
Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...
(1972–2003)
The last successful reception of telemetry from Pioneer 10 was on April 27, 2002, when it was at a distance of 80.22 AU. Traveling at about 2.54 AU/year (12 km/second).
Pioneer 11
Pioneer 11
Pioneer 11 is a 259-kilogram robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind, cosmic rays, and eventually the far reaches of the solar system and heliosphere...
(1973–1995)
Routine mission operations for Pioneer 11 were stopped September 30, 1995, when it was 6.5 billion km (approx 43.4 AU) from Earth. Traveling at about 2.4 AU/year (11.4 km/second).
See also: Spacecraft escaping the Solar System, Probes leaving the Solar System, Artificial objects escaping the solar system
Trans-neptunian probes at precursor distances
In the early 2000s many new, relatively large planetary bodies were found beyond what was at the time planet Pluto, and with orbits extending hundreds of AU out past the heliosheath (90-1000 AU). The NASA probe New Horizons may explore this area after it performs its planned Pluto flyby in 2015 (Pluto ranges from about 29-49 AU). Some of these large objects past Pluto include Eris (136199), Haumea (136108), Makemake (136472), and Sedna90377 Sedna
90377 Sedna is a trans-Neptunian object discovered in 2003, which was about three times as far from the Sun as Neptune. For most of its orbit it is even further from the Sun, with its aphelion estimated at 960 astronomical units , making it one of the most distant known objects in the Solar System...
(90377). Sedna comes as close as 76 AU, but travels out as far as 961 AU at aphelion, and minor planet 87269
(87269) 2000 OO67
' is a small trans-Neptunian object discovered by Deep Ecliptic Survey in 2000.It is remarkable for its highly eccentric orbit. At aphelion it is over 1,000 AU from the Sun and, with a perihelion of 21 AU, almost crosses the orbit of Uranus at closest approach. is probably composed of rock and...
goes out past 1060 AU at aphelion. Bodies like these have an impact on how the Solar System is understood, and traverse an area previously only in the domain of interstellar missions or precursors probes. After the discoveries, the area is also in the domain of interplanetary probes; some of the discovered bodies may become targets for exploration missions, an example of which is preliminary work on a probe to Haumea (136108) and its moons (at 35-51 AU). Probe mass, power source, and propulsion systems are key technology areas for this type of mission. In addition, a feature of this area is the gravitational lensing point of the Sun at about 550 AU.
Proposed interstellar probes
Missions intended to reach the interstellar medium.Innovative Interstellar Explorer
Innovative Interstellar Explorer
Innovative Interstellar Explorer was a NASA "Vision Mission" study funded by NASA following a proposal under NRA-03-OSS-01 on 11 September 2003. This study has focused on the elusive quest to reach and measure the interstellar medium, the "undiscovered country" outside of the influence of the...
(2003+)
NASA proposal to send a 35 kg science payload out to at least 200 AU. It would achieve a top speed of 7.8 AU per year using a combination of a heavy lift rocket, Jupiter gravitational assistance, and an ion engine powered by standard radioisotope thermal generators. The probe suggested a launch in 2014 (to take advantage of Jupiter gravitational assist), to reach 200 AU around 2044.
Realistic Interstellar Explorer & Interstellar Explorer (2000–2002)
Studies suggesting various technologies including Am-241 based RTG, optical communication (as opposed to radio), and low-power semi-autonomous electronics. Trajectory uses a Jupiter and Sun gravity assist to achieve 20 AU/year, allowing 1000 AU within 50 years, and a mission extension up to 20 thousand AU and 1000 years. Needed technology included advanced propulsion and solar shield for perihelion burn around the sun. Solar thermal (STP), nuclear fission thermal (NTP), and nuclear fission pulse, as well as various RTG isotopes were examined. The studies also included recommendations for a solar probe (see also Solar Probe Plus), nuclear thermal technology, solar sail probe, 20 AU/year probe, and a long term vision of a 200 AU/year probe to the star Epsilon Eridani
Epsilon Eridani
Epsilon Eridani is a star in the southern constellation Eridanus, along a declination 9.46° south of the celestial equator. This allows the star to be viewed from most of the Earth's surface. At a distance of 10.5 light years , it has an apparent magnitude of 3.73...
.
The "next step" interstellar probe in this study suggested a 5 megawatt fission reactor utilizing 16 metric tonnes of H2 propellant. Targeting a launch in the mid-21st century, it would accelerate to 200 AU/year over 4200 AU and reach the star Epsilon Eridani
Epsilon Eridani
Epsilon Eridani is a star in the southern constellation Eridanus, along a declination 9.46° south of the celestial equator. This allows the star to be viewed from most of the Earth's surface. At a distance of 10.5 light years , it has an apparent magnitude of 3.73...
after 3400 years of travel in the year 5500 AD. However, this was a 2nd generation vision for a probe and the study acknowledged that even 20 AU/year might not be possible with then current (2002) technology. For comparison, the fastest probe at the time of the study was Voyager 1
Voyager 1
The Voyager 1 spacecraft is a 722-kilogram space probe launched by NASA in 1977, to study the outer Solar System and eventually interstellar space. Operating for as of today , the spacecraft receives routine commands and transmits data back to the Deep Space Network. At a distance of as of...
at about 3.6 AU/year (17 km/s), relative to the sun.
Interstellar Probe was a proposed solar sail
Solar sail
Solar sails are a form of spacecraft propulsion using the radiation pressure of light from a star or laser to push enormous ultra-thin mirrors to high speeds....
propulsion spacecraft planned by NASA Jet Propulsion Laboratory. It was planned to reach as far as 200 AU within 10 years at a speed of 14 AU/year (about 70 km/s), and function up to 400+ AU. A critical technology for the mission is a large 1 g/m2 solar sail. The probe itself hoped to use an advanced RTG for electrical power, Ka-band radio for communication with Earth, Delta 2 for Earth launch, and a 25 kg instrument package using 20 watts.
(Mewaldt et al., 1995)
Study for 200 kg probe traveling at 6 to 14 AU/ year using chemical and planetary or solar gravity assists.
(Holzer et al., 1990)
Study for 1000 kg probe traveling at 10 AU/year using chemical and a solar gravity assist, to collect data out to 200 AU from the Sun.
TAU mission
TAU mission
TAU was a proposed unmanned space probe to a distance of one thousand astronomical units from the Earth and Sun by NASA/JPL in 1987 using tested technology...
(1987)
TAU mission (Thousand Astronomical Units) was a proposed nuclear electric rocket
Nuclear electric rocket
In a nuclear electric rocket, nuclear thermal energy is changed into electrical energy that is used to power one of the electrical propulsion technologies. Technically the powerplant is nuclear, not the propulsion system, but the terminology is standard. A number of heat-to-electricity schemes...
craft that used a 1 MW fission reactor and an ion drive with a burn time of about 10 years to reach a speed of 106 km/s (about 20 AU/year) to achieve a distance of 1000 AU in 50 years. The primary goal of the mission was to improve parallax measurements of the distances to stars inside and outside of our galaxy, with secondary goals being the study of the heliopause, measurements of conditions in the interstellar medium
Interstellar medium
In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
, and (via communications with Earth) tests of general relativity
General relativity
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...
.
Interstellar Precursor Mission (Jaffe, 1977–1979)
Proposed nuclear electric power/propulsion for a probe to 370 AU in 20 years and 1030 AU in 50 years from launch.
Interstellar concepts
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)
Project Orion was a proposed nuclear pulse propulsion
Nuclear pulse propulsion
Nuclear pulse propulsion is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1947...
craft that used fission or fusion bombs to apply motive force. The design was studied during the 1950s and 1960s in the United States of America, with one variant of the craft capable of interstellar travel
Interstellar travel
Interstellar space travel is manned or unmanned travel between stars. The concept of interstellar travel in starships is a staple of science fiction. Interstellar travel is much more difficult than interplanetary travel. Intergalactic travel, or travel between different galaxies, is even more...
.
Bracewell probe
Bracewell probe
A Bracewell probe is a hypothetical concept for an autonomous interstellar space probe dispatched for the express purpose of communication with one or more alien civilizations. It was proposed by Ronald N...
(1960)
Interstellar communication
Interstellar communication
Interstellar communication is the transmission of signals between planetary systems. Sending Interstellar messages is potentially much easier than interstellar travel, being possible with technologies and equipment which are currently available...
via a probe, as opposed to sending an electromagnetic signal.
Sanger Photon Rocket (1950s-1964)
Eugene Sanger proposed a spacecraft powered by antimatter in the 1950s. Thrust was intended to come from reflected gamma-rays produced by electron-positron
Positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1e, a spin of ½, and has the same mass as an electron...
annihilation.
Enzmann Starship
Enzmann starship
The Enzmann starship is a concept for a manned interstellar spacecraft proposed in 1964 by Robert Enzmannn. A 1973 iteration, projected using a 12,000,000 ton ball of frozen deuterium to power thermonuclear powered pulse propulsion units, similar to Project Orion engines...
(1964/1973)
Proposed by 1964 and examined in a October 1973 issue of Analog
Analog Science Fiction and Fact
Analog Science Fiction and Fact is an American science fiction magazine. As of 2011, it is the longest running continuously published magazine of that genre...
, the Enzmann Starship
Enzmann starship
The Enzmann starship is a concept for a manned interstellar spacecraft proposed in 1964 by Robert Enzmannn. A 1973 iteration, projected using a 12,000,000 ton ball of frozen deuterium to power thermonuclear powered pulse propulsion units, similar to Project Orion engines...
proposed using a 12,000 ton ball of frozen deuterium to power thermonuclear powered pulse propulsion. About twice as long as the Empire State Building
Empire State Building
The Empire State Building is a 102-story landmark skyscraper and American cultural icon in New York City at the intersection of Fifth Avenue and West 34th Street. It has a roof height of 1,250 feet , and with its antenna spire included, it stands a total of 1,454 ft high. Its name is derived...
and assembled in-orbit, the spacecraft was part of a larger project preceded by large interstellar probes and telescopic observation of target star systems.
Project Daedalus
Project Daedalus
Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society to design a plausible unmanned interstellar spacecraft. Intended mainly as a scientific probe, the design criteria specified that the spacecraft had to use current or near-future technology and had to...
(1973–1978)
Project Daedalus was a proposed nuclear pulse propulsion
Nuclear pulse propulsion
Nuclear pulse propulsion is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1947...
craft that used inertial confinement fusion
Inertial confinement fusion
Inertial confinement fusion is a process where nuclear fusion reactions are initiated by heating and compressing a fuel target, typically in the form of a pellet that most often contains a mixture of deuterium and tritium....
of small pellets within a magnetic field nozzle to provide motive force. The design was studied during the 1970s by the British Interplanetary Society
British Interplanetary Society
The British Interplanetary Society founded in 1933 by Philip E. Cleator, is the oldest space advocacy organisation in the world whose aim is exclusively to support and promote astronautics and space exploration.-Structure:...
, and was meant to flyby Barnard's Star
Barnard's star
Barnard's Star, also known occasionally as Barnard's "Runaway" Star, is a very low-mass red dwarf star approximately six light-years away from Earth in the constellation of Ophiuchus . In 1916, the American astronomer E.E...
in under a century from launch. Plans included mining Helium-3 from Jupiter and a pre-launch mass of over 50 thousand metric tonnes from orbit.
Project Longshot
Project Longshot
Project Longshot was a conceptual design for an interstellar spacecraft, an unmanned probe intended to fly to Alpha Centauri powered by nuclear pulse propulsion. Developed by the US Naval Academy and NASA from 1987 to 1988, Longshot was designed to be built at Space Station Freedom, the precursor...
(1987–1988)
Project Longshot was a proposed nuclear pulse propulsion
Nuclear pulse propulsion
Nuclear pulse propulsion is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1947...
craft that used inertial confinement fusion
Inertial confinement fusion
Inertial confinement fusion is a process where nuclear fusion reactions are initiated by heating and compressing a fuel target, typically in the form of a pellet that most often contains a mixture of deuterium and tritium....
of small pellets within a magnetic field nozzle to provide motive force, in a manner similar to that of Project Daedalus. The design was studied during the 1990s by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
and the US Naval Academy. The craft was designed to reach and study Alpha Centauri
Alpha Centauri
Alpha Centauri is the brightest star in the southern constellation of Centaurus...
.
Starwisp
Starwisp
Starwisp is a hypothetical unmanned interstellar probe design proposed by Robert L. Forward. It is propelled by a microwave sail, similar to a solar sail in concept, but powered by microwaves from a man-made source.- Description :...
(1985)
Starwisp is a hypothetical unmanned interstellar probe design proposed by Robert L. Forward. It is propelled by a microwave sail, similar to a solar sail in concept, but powered by microwaves from an artificial source.
Medusa (1990s)
Medusa was a proposed nuclear pulse propulsion
Nuclear pulse propulsion
Nuclear pulse propulsion is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1947...
craft that used fission or fusion bombs to provide propulsion, with a structure similar to a light sail
Solar sail
Solar sails are a form of spacecraft propulsion using the radiation pressure of light from a star or laser to push enormous ultra-thin mirrors to high speeds....
used to derive motive force from the bombs' blast waves. The design was studied during the 1990s by the British Interplanetary Society
British Interplanetary Society
The British Interplanetary Society founded in 1933 by Philip E. Cleator, is the oldest space advocacy organisation in the world whose aim is exclusively to support and promote astronautics and space exploration.-Structure:...
as a means of interplanetary travel.
Starseed launcher
Starseed launcher
Starseed is a proposed method of launching interstellar nanoprobes at one-third light speed suggested by Forrest Bishop of the Institute of Atomic-Scale Engineering....
(1996)
Starseed launcher was concept for launching microgram interstellar probes at up to 1/3 light speed.
AIMStar (1990s-2000s)
AIMStar was a proposed antimatter catalyzed nuclear pulse propulsion
Antimatter catalyzed nuclear pulse propulsion
Antimatter catalyzed nuclear pulse propulsion is a variation of nuclear pulse propulsion based upon the injection of antimatter into a mass of nuclear fuel which normally would not be useful in propulsion...
craft that used clouds of antiproton
Antiproton
The antiproton is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived since any collision with a proton will cause both particles to be annihilated in a burst of energy....
s to initiate fission and fusion within fuel pellets. A magnetic nozzle derived motive force from the resulting explosions. The design was studied during the 1990s by Penn State University. The craft was designed to reach a distance of 10,000 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
in 50 years.
Project Icarus (Interstellar Probe Design Study)
Project Icarus is a theoretical design study aimed at designing a credible nuclear fusion-based interstellar spacecraft that will stand as a blueprint for a possible unmanned mission...
(2009+)
Project Icarus is theoretical study for a interstellar probe and is being run under the guidance of the Tau Zero Foundation (TZF) and the British Interplanetary Society
British Interplanetary Society
The British Interplanetary Society founded in 1933 by Philip E. Cleator, is the oldest space advocacy organisation in the world whose aim is exclusively to support and promote astronautics and space exploration.-Structure:...
(BIS), and was motivated by Project Daedalus
Project Daedalus
Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society to design a plausible unmanned interstellar spacecraft. Intended mainly as a scientific probe, the design criteria specified that the spacecraft had to use current or near-future technology and had to...
, a similar study that was conducted between 1973 and 1978 by the BIS. The project is planned to take five years and began on September 30, 2009
Other interplanetary probes of interest
Other probes of interest to suggested interstellar missions.- NASA Dawn (launched 2007), Using solar powered xenon ion thrusters, achieving a velocity changeDelta-vIn astrodynamics a Δv or delta-v is a scalar which takes units of speed. It is a measure of the amount of "effort" that is needed to change from one trajectory to another by making an orbital maneuver....
of over 10 km/s - Solar Probe Plus, planned probe approaches Sun within about 8-9 solar radii. (Interstellar probes using Solar gravity assist need to survive Sun perihelion)
- Deep Space 1Deep Space 1Deep Space 1 is a spacecraft of the NASA New Millennium Program dedicated to testing a payload of advanced, high risk technologies....
(1999–2001), demonstrated ion engines and Ka-band radio communications. - Ulysses (1990–2009), Out-Of-The-Ecliptic mission meant large velocity change of 15.4 km/s (IUS & Pam-S booster) and Jupiter gravity assist. Used RTG for power.
- IKAROSIKAROSIKAROS is a Japan Aerospace Exploration Agency experimental spacecraft. The spacecraft was launched on 21 May, 2010, aboard an H-IIA rocket, together with the Akatsuki probe and four other small spacecraft...
(2010) & NanoSail-D2NanoSail-D2NanoSail-D2 is a small satellite built by NASA's Marshall Space Flight Center and Ames Research Center to study the deployment of a solar sail in space. It is a three-unit CubeSat measuring 30 by 10 by 10 centimeters , with a mass of...
, solar sail propulsion tests
See also
Selected programs- NERVANERVANERVA is an acronym for Nuclear Engine for Rocket Vehicle Application, a joint program of the U.S. Atomic Energy Commission and NASA managed by the Space Nuclear Propulsion Office until both the program and the office ended at the end of 1972....
(ending 1972), tested nuclear fission thermal rocket engine - NASA Project PrometheusProject PrometheusProject 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 NERVA project in 1972...
(ending 2006)- Jupiter Icy Moons OrbiterJupiter Icy Moons OrbiterThe Jupiter Icy Moons Orbiter was a proposed spacecraft designed to explore the icy moons of Jupiter. The main target was Europa, the suspected ocean of which is one of the places where simple alien life is a possibility in our solar system...
(ending 2005), nuclear fission electric ion engine
- Jupiter Icy Moons Orbiter
- Breakthrough Propulsion Physics ProgramBreakthrough Propulsion Physics ProgramThe Breakthrough Propulsion Physics Project was a research project funded by NASA from 1996 through 2002, to study various proposals for "revolutionary" methods of spacecraft propulsion which would require breakthroughs in physics before they could be realized, hence the name...
(1996–2002), evaluated advanced propulsion technology - Interstellar Boundary Explorer (IBEX)Interstellar Boundary ExplorerInterstellar Boundary Explorer is a NASA satellite that will make the first map of the boundary between the Solar System and interstellar space. The mission is part of NASA's Small Explorer program. The IBEX satellite was launched with a Pegasus-XL rocket on October 19, 2008, at 17:47:23 UTC...
(2008), space observatory that measured energetic neutral atoms from interstellar boundary.
Outer Space
- List of nearest stars (nearest to Earth)
- HeliosphereHeliosphereThe heliosphere is a bubble in space "blown" into the interstellar medium by the solar wind. Although electrically neutral atoms from interstellar volume can penetrate this bubble, virtually all of the material in the heliosphere emanates from the Sun itself...
& Interstellar MediumInterstellar mediumIn astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space... - Kuiper beltKuiper beltThe Kuiper belt , sometimes called the Edgeworth–Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune to approximately 50 AU from the Sun. It is similar to the asteroid belt, although it is far larger—20 times as wide and 20 to 200 times as massive...
(30-50 AU) & Oort cloudOort cloudThe Oort cloud , or the Öpik–Oort cloud , is a hypothesized spherical cloud of comets which may lie roughly 50,000 AU, or nearly a light-year, from the Sun. This places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun...
(2,000 to 200,000 AU) - Local Interstellar CloudLocal Interstellar CloudThe Local Interstellar Cloud is the interstellar cloud roughly 30 light years across through which the Earth's solar system is currently moving. The Solar System is thought to have entered the Local Interstellar Cloud at some time between 44,000 and 150,000 years ago and is expected to remain...
(aka Local Fluff & 30 light years across) & Local BubbleLocal BubbleThe Local Bubble is a cavity in the interstellar medium of the Orion Arm of the Milky Way. It is at least 300 light years across and has a neutral hydrogen density of about 0.05 atoms per cubic centimetre, or approximately one tenth of the average for the ISM in the Milky Way , and half that for...
(300 light years across) (1 light-year ≈ 63,241 AU) - Examples of distance in AU
Space travel
- Interplanetary travelInterplanetary travelInterplanetary spaceflight or interplanetary travel is travel between planets within a single planetary system. In practice, spaceflights of this type are confined to travel between the planets of the Solar System....
- Interstellar travelInterstellar travelInterstellar space travel is manned or unmanned travel between stars. The concept of interstellar travel in starships is a staple of science fiction. Interstellar travel is much more difficult than interplanetary travel. Intergalactic travel, or travel between different galaxies, is even more...
- Intergalactic travelIntergalactic travelIntergalactic travel is space travel between galaxies. Due to the relatively enormous distances between our own galaxy and even its closest neighbors, any such venture would be far more technologically demanding than even interstellar travel...
Further reading
- NASA's Interstellar Probe Mission (1999) (.pdf)
- Leonard David - Reaching for interstellar flight (2003) - MSNBC (MSNBC Webpage)
- Ralph L. McNutt, et al. - A Realistic Interstellar Explorer (2000) - Johns Hopkins University (.pdf)
- McNutt, et al. - Radioisotope Electric Propulsion (2006) - NASA Glenn Research Center (includes Centaur orbiter mission)
- Scott W. Benson - Solar Power for Outer Planets Study (2007) - NASA Glenn Research Center (with SEP booster)