An interstellar probe is a space probe that has left—or is expected to leave—the Solar System and enter interstellar space , which is typically defined as the region beyond the heliopause . It also refers to probes capable of reaching other star systems .
104-478: The Voyager program is an American scientific program that employs two interstellar probes , Voyager 1 and Voyager 2 . They were launched in 1977 to take advantage of a favorable planetary alignment to explore the two gas giants Jupiter and Saturn and potentially also the ice giants, Uranus and Neptune - to fly near them while collecting data for transmission back to Earth. After Voyager 1 successfully completed its flyby of Saturn and its moon Titan , it
208-421: A SLS in the 2030s. It would perform either a fast Jupiter flyby, a powered Jupiter flyby, or a very close perihelion and propulsive maneuver, and reach a distance of 1000–2000 AU (93-186 billion miles; about 1.5-3% of one light-year) within 50 years. Possibilities for planetary, astrophysical and exoplanet science along the way are also being investigated. A technology reference study published in 2006 with
312-523: A STAR-48 booster, is on a similar escape trajectory out of the Solar System as New Horizons , but will pass millions of kilometers from Pluto. It crossed Pluto's orbit in October 2015. The third stage rocket boosters for Pioneer 10 , Voyager 1 , and Voyager 2 are also on escape trajectories out of the Solar System. In April 2016, Breakthrough Initiatives announced Breakthrough Starshot ,
416-613: A Titan flyby, while JSX served as a contingency plan. JST focused on a Titan flyby, while JSX provided a flexible mission plan. If JST succeeded, JSX could proceed with the Grand Tour, but in case of failure, JSX could be redirected for a separate Titan flyby, forfeiting the Grand Tour opportunity. The second probe, now Voyager 2 , followed the JSX trajectory, granting it the option to continue on to Uranus and Neptune. Upon Voyager 1 completing its main objectives at Saturn, Voyager 2 received
520-405: 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 our galaxy, with secondary goals being the study of the heliopause , measurements of conditions in
624-570: 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. Studies suggest various technologies including americium-241 -based RTG, optical communication (as opposed to radio), and low-power semi-autonomous electronics. Trajectory uses
728-411: A JST or JSX trajectory. After completing their flybys, the probes would communicate with Earth, relaying vital data using their magnetometers , spectrometers , and other instruments to detect interstellar , solar , and cosmic radiation . Their radioisotope thermoelectric generators (RTGs) would limit the maximum communication time with the probes to roughly a decade . Following their primary missions,
832-503: A Jupiter gravity assist and Solar Oberth maneuver to achieve 20 AU/year, allowing 1000 AU within 50 years, and a mission extension up to 20,000 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
936-470: A commandable filter wheel mounted in front of the vidicons. One has a low resolution 200 mm (7.9 in) focal length wide-angle lens with an aperture of f/3 (the wide-angle camera), while the other uses a higher resolution 1,500 mm (59 in) narrow-angle f/8.5 lens (the narrow-angle camera). Three spacecraft were built, Voyager 1 (VGR 77-1), Voyager 2 (VGR 77-3), and test spare model (VGR 77-2). There are three different computer types on
1040-512: A dish antenna that would be pointed at Earth. Each would also carry a host of scientific instruments. Some of the instruments, such as cameras, would need to be pointed at the target body it was studying. Other instruments were non-directional and studied phenomena such as magnetic fields and charged particles. JPL engineers proposed to make the Mariners "three-axis-stabilized," meaning that unlike other space probes they would not spin. Each of
1144-470: A distance of 94 AU from the Sun. At the end of 2011, Voyager 1 entered and discovered a stagnation region where charged particles streaming from the Sun slow and turn inward, and the Solar System's magnetic field is doubled in strength as interstellar space appears to be applying pressure. Energetic particles originating in the Solar System declined by nearly half, while the detection of high-energy electrons from outside increases 100-fold. The inner edge of
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#17327726981101248-556: A hexagonal or octagonal bus , which housed all of the electronics, and to which all components were attached, such as antennae, cameras, propulsion, and power sources. Mariner 2 was based on the Ranger Lunar probe. All of the Mariners launched after Mariner 2 had four solar panels for power, except for Mariner 10 , which had two. Additionally, all except Mariner 1 , Mariner 2 and Mariner 5 had TV cameras. The first five Mariners were launched on Atlas-Agena rockets , while
1352-489: A manner similar to that of Project Daedalus. The design was studied during the 1990s by NASA and the US Naval Academy . The craft was designed to reach and study Alpha Centauri . 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
1456-489: A mission extension, enabling it to proceed to Uranus and Neptune. This allowed Voyager 2 to diverge from the originally planned JST trajectory. The probes would be launched in August or September 1977, with their main objective being to compare the characteristics of Jupiter and Saturn, such as their atmospheres , magnetic fields , particle environments, ring systems , and moons . They would fly by planets and moons in either
1560-572: A mission extension, which began when the two spacecraft had already been in flight for over 12 years. The Heliophysics Division of the NASA Science Mission Directorate conducted a Heliophysics Senior Review in 2008. The panel found that the VIM "is a mission that is absolutely imperative to continue" and that VIM "funding near the optimal level and increased DSN ( Deep Space Network ) support is warranted." The main objective of
1664-566: A probe beyond 550 AU could use the Sun itself as a gravitational lens to observe targets outside the Solar System, such as planetary systems around other nearby stars, although many challenges to this mission have been noted. Mariner program The Mariner program was conducted by the American space agency NASA to explore other planets . Between 1962 and late 1973, NASA's Jet Propulsion Laboratory (JPL) designed and built 10 robotic interplanetary probes named Mariner to explore
1768-522: A probe, as opposed to sending an electromagnetic signal. Eugene Sanger proposed a spacecraft powered by antimatter in the 1950s. Thrust was intended to come from reflected gamma-rays produced by electron- positron annihilation. Proposed by 1964 and examined in an October 1973 issue of Analog , the Enzmann Starship proposed using a 12,000 ton ball of frozen deuterium to power thermonuclear powered pulse propulsion. About twice as long as
1872-459: A program to develop a proof of concept fleet of small centimeter-sized light sail spacecraft, named StarChip , capable of making the journey to Alpha Centauri , the nearest star system , at speeds of 20% and 15% of the speed of light , taking between 20 and 30 years to reach the star system, respectively, and about 4 years to notify Earth of a successful arrival. A CNSA space mission first proposed in 2019 would be launched in 2024 with
1976-592: A project working on small interstellar spacecraft, propelled by a laser sail in 2014 under the name of Project Dragonfly . Four student teams worked on concepts for such a mission in 2014 and 2015 in the context of a design competition. In 2016, the Breakthrough Initiatives announced a program to develop a fleet of lightweight light-sail probes for interstellar travel, aiming to make the journey to Alpha Centauri . This research program, with an initial funding of US$ 100 million imagines accelerating
2080-551: A revised power management plan was implemented to better manage the two probes' dwindling power supply. The Voyager spacecraft each weighed 815 kilograms (1,797 pounds) at launch, but after fuel usage are now about 733 kilograms (1,616 pounds). Of this weight, each spacecraft carries 105 kilograms (231 pounds) of scientific instruments. The identical Voyager spacecraft use three-axis-stabilized guidance systems that use gyroscopic and accelerometer inputs to their attitude control computers to point their high-gain antennas towards
2184-511: A scaled back mission involving flybys of only the two gas giants, though designers at JPL built the craft with the intention that further encounters past Saturn would be an option. Trajectories were chosen to allow one probe to visit Jupiter and Saturn first, and perform a flyby of Saturn's moon Titan to gather information about the moon's substantial atmosphere. The other probe would arrive at Jupiter and Saturn later, and its trajectory would enable it to continue on to Uranus and Neptune assuming
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#17327726981102288-474: A scientific subsystem that the other lacks. According to Guinness Book of Records, CCS holds record of "longest period of continual operation for a computer". It has been running continuously since 20 August 1977. The Attitude and Articulation Control Subsystem (AACS) controls the spacecraft orientation (its attitude). It keeps the high-gain antenna pointing towards the Earth, controls attitude changes, and points
2392-514: A separate program named Mariner Jupiter-Saturn (also Mariner Jupiter-Saturn-Uranus , MJS , or MJSU ), part of the Mariner program , later renamed because it was thought that the design of the two space probes had progressed sufficiently beyond that of the Mariner family to merit a separate name. On March 4, 1977, NASA announced a competition to rename the mission, believing the existing name
2496-450: A solar probe (see also Parker Solar Probe ), 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 . The "next step" interstellar probe in this study suggested a 5 megawatt fission reactor utilizing 16 metric tonnes of H 2 propellant. Targeting a launch in the mid-21st century, it would accelerate to 200 AU/year over 4200 AU and reach
2600-407: A ton (without onboard rocket propellant). Each of their missions was completed within a few months to a year or two, though one of them outlived its original mission and continued to send useful scientific data for three years. (decommissioned) (decommissioned) Mariner 1 (P-37) and Mariner 2 (P-38) were two deep-space probes making up NASA's Mariner-R project. The primary goal of the project
2704-622: Is a theoretical study for an interstellar probe and is being run under the guidance of the Tau Zero Foundation (TZF) and the British Interplanetary Society (BIS), and was motivated by Project Daedalus , 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. The Initiative for Interstellar Studies (i4is) has initiated
2808-430: Is an E-sail . By harnessing solar wind, it might be possible to achieve 20-30 AU per year without even using propellant. Voyager 1 is a space probe launched by NASA on September 5, 1977. At a distance of about 162.755 AU (2.435 × 10 km) as of 22 November 2024, it is the farthest manmade object from Earth . It was later estimated that Voyager 1 crossed the termination shock on December 16, 2004 at
2912-620: Is attached to one of the bus sides. The angled square panel to the right is the optical calibration target and excess heat radiator. The three radioisotope thermoelectric generators (RTGs) are mounted end-to-end on the lower boom. The scan platform comprises: the Infrared Interferometer Spectrometer (IRIS) (largest camera at top right); the Ultraviolet Spectrometer (UVS) just above the IRIS;
3016-456: Is moving with a velocity of 55,347 kilometers per hour (34,391 mph), or 15 km/s, relative to the Sun, and is 20,439,100,000 kilometers (1.27003 × 10 mi) from the Sun reaching a distance of 136.627 AU (20.4 billion km ; 12.7 billion mi ) from Earth as of May 25, 2024. The two Voyagers are the only human-made objects to date that have passed into interstellar space—a record they will hold until at least
3120-639: Is two 16-bit word machines with modular memories and 8198 words each. The Attitude and Articulation Control System (AACS) is two 18-bit word machines with 4096 words each. Unlike the other on-board instruments, the operation of the cameras for visible light is not autonomous, but rather it is controlled by an imaging parameter table contained in one of the on-board digital computers , the Flight Data Subsystem (FDS). More recent space probes, since about 1990, usually have completely autonomous cameras. The computer command subsystem (CCS) controls
3224-459: The American space agency NASA : Voyager 1 , Voyager 2 , Pioneer 10 , Pioneer 11 and New Horizons . Also as of 2024, Voyager 1 and Voyager 2 are the only probes to have actually reached interstellar space. The other three are on interstellar trajectories. Contact to Pioneer 10 and 11 was lost long before they reached interstellar space. The termination shock is the point in
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3328-461: The Breakthrough Initiatives . Planetary scientist G. Laughlin noted that, with current technology, a probe sent to Alpha Centauri would take 40,000 years to arrive, but expressed hope for new technology to be developed to make the trip within a human lifetime. On that timescale, the stars move notably. As an example, in 40,000 years Ross 248 will be closer to Earth than Alpha Centauri. One technology that has been proposed to achieve higher speeds
3432-404: The British Interplanetary Society , and was meant to flyby Barnard's Star 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 was a proposed nuclear pulse propulsion craft that used inertial confinement fusion of small pellets within a magnetic field nozzle to provide motive force, in
3536-482: The Empire State Building 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 was a proposed nuclear pulse propulsion craft that used inertial confinement fusion of small pellets within a magnetic field nozzle to provide motive force. The design was studied during the 1970s by
3640-456: The Oort cloud in about 300 years. Voyager 2 crossed the heliopause and entered interstellar space on November 5, 2018. It had previously passed the termination shock into the heliosheath on August 30, 2007. As of 22 November 2024 Voyager 2 is at a distance of 133.101 AU (1.991 × 10 km) from Earth. The probe was moving at a velocity of 3.25 AU/year (15.428 km/s) relative to
3744-524: The Voyager 2 probe had officially reached the interstellar medium (ISM), a region of outer space beyond the influence of the solar wind , as did Voyager 1 in 2012. In August 2018, NASA confirmed, based on results by the New Horizons spacecraft, the existence of a " hydrogen wall " at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft. As of 2024,
3848-651: The heliopause on 25 August 2012, making it the first spacecraft to enter interstellar space. In December 2018, NASA announced that Voyager 2 had crossed the heliopause on 5 November 2018, making it the second spacecraft to enter interstellar space. As of 2017 Voyager 1 and Voyager 2 continue to monitor conditions in the outer expanses of the Solar System. The Voyager spacecraft are expected to be able to operate science instruments through 2020, when limited power will require instruments to be deactivated one by one. Sometime around 2025, there will no longer be sufficient power to operate any science instruments. In July 2019,
3952-499: The heliosphere where the solar wind slows down to subsonic speed. Even though the termination shock happens as close as 80–100 AU ( astronomical units ) the maximum extent of the region in which the Sun's gravitational field is dominant (the Hill sphere ) is thought to be at around 230,000 astronomical units (3.6 light-years). This point is close to the nearest known star system, Alpha Centauri , located 4.36 light years away. Although
4056-472: The interstellar medium , and (via communications with Earth) tests of general relativity . Project Orion was a proposed nuclear pulse propulsion craft that would have 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 communication via
4160-482: The solar wind . Two significant findings so far have been the discovery of a region of magnetic bubbles and no indication of an expected shift in the Solar magnetic field. The entire Voyager 2 scan platform, including all of the platform instruments, was switched off in 1998. All platform instruments on Voyager 1 , except for the ultraviolet spectrometer (UVS) have also been switched off. The Voyager 1 scan platform
4264-421: The 1990s, Voyager 1 overtook the slower deep-space probes Pioneer 10 and Pioneer 11 to become the most distant human-made object from Earth, a record that it will keep for the foreseeable future. The New Horizons probe, which had a higher launch velocity than Voyager 1 , is travelling more slowly due to the extra speed Voyager 1 gained from its flybys of Jupiter and Saturn. Voyager 1 and Pioneer 10 are
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4368-494: The 2040's—and Voyager 1 is the farthest human-made object from Earth. Voyager did things no one predicted, found scenes no one expected, and promises to outlive its inventors. Like a great painting or an abiding institution, it has acquired an existence of its own, a destiny beyond the grasp of its handlers. The two Voyager space probes were originally conceived as part of the Planetary Grand Tour planned during
4472-515: The ESA proposed an interstellar probe focused on leaving the heliosphere. The goal would be 200 AU in 25 years, with traditional launch but acceleration by a solar sail . The roughly 200–300 kg probe would carry a suite of several instruments including a plasma analyzer, plasma radio wave experiment, magnetometer, neutral and charged atom detector, dust analyzer, and a UV-photometer. Electrical power would come from an RTG . NASA proposal to send
4576-458: The Earth and their scientific instruments towards their targets, sometimes with the help of a movable instrument platform for the smaller instruments and the electronic photography system. The diagram shows the high-gain antenna (HGA) with a 3.7 m (12 ft) diameter dish attached to the hollow decagonal electronics container. There is also a spherical tank that contains the hydrazine monopropellant fuel. The Voyager Golden Record
4680-527: The Earth. Electrical power is supplied by three MHW-RTG radioisotope thermoelectric generators (RTGs). They are powered by plutonium-238 (distinct from the Pu-239 isotope used in nuclear weapons) and provided approximately 470 W at 30 volts DC when the spacecraft was launched. Plutonium-238 decays with a half-life of 87.74 years, so RTGs using Pu-238 will lose a factor of 1−0.5 = 0.79% of their power output per year. In 2011, 34 years after launch,
4784-600: The Earth. For example, the data rate used from Jupiter was about 115,000 bits per second. That was halved at the distance of Saturn, and it has gone down continually since then. Some measures were taken on the ground along the way to reduce the effects of the inverse-square law. In between 1982 and 1985, the diameters of the three main parabolic dish antennas of the Deep Space Network were increased from 64 to 70 m (210 to 230 ft) dramatically increasing their areas for gathering weak microwave signals. Whilst
4888-559: The Mariner program was approximately $ 554 million. The Mariner program began in 1960 with a series of JPL mission studies for small-scale, frequent exploration of the nearest planets. They were to take advantage of the soon-to-be-available Atlas launch vehicles as well as the developing capability of JPL's Deep Space Instrumentation Facility (later named the Deep Space Network), a global network of ground stations designed to communicate with spacecraft in deep space. The name of
4992-409: The Mariner program was decided in "May 1960 – at the suggestion of Edgar M. Cortright" to have the "planetary mission probes ... patterned after nautical terms, to convey 'the impression of travel to great distances and remote lands.'" That "decision was the basis for naming Mariner, Ranger, Surveyor, and Viking probes." Each spacecraft was to carry solar panels that would be pointed toward the Sun and
5096-411: The Mariner projects was designed to have two spacecraft launched on separate rockets, in case of difficulties with the nearly untried launch vehicles. Mariner 1, Mariner 3, and Mariner 8 were in fact lost during launch, but their backups were successful. No Mariners were lost in later flight to their destination planets or before completing their scientific missions. All Mariner spacecraft were based on
5200-494: The Solar System is understood, and traverse an area previously only in the domain of interstellar missions or precursor 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 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,
5304-448: The Sun on its way to interstellar space in 2013. It's moving at a velocity of 15.4 km/s (55,000 km/h) relative to the Sun as of December 2014. Voyager 2 is expected to provide the first direct measurements of the density and temperature of the interstellar plasma. New Horizons was launched directly into a hyperbolic escape trajectory, getting a gravitational assist from Jupiter en route. By March 7, 2008, New Horizons
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#17327726981105408-485: The Sun. The Heliosphere's termination shock was crossed by Voyager 1 at 94 astronomical units (AU) and Voyager 2 at 84 AU according to the IBEX mission. If New Horizons can reach the distance of 100 AU , it will be traveling at about 13 km/s (29,000 mph), around 4 km/s (8,900 mph) slower than Voyager 1 at that distance. The last successful reception of telemetry from Pioneer 10
5512-452: The VIM was to extend the exploration of the Solar System beyond the outer planets to the heliopause (the farthest extent at which the Sun's radiation predominates over interstellar winds) and if possible even beyond. Voyager 1 crossed the heliopause boundary in 2012, followed by Voyager 2 in 2018. Passing through the heliopause boundary has allowed both spacecraft to make measurements of the interstellar fields, particles and waves unaffected by
5616-481: The Voyager spacecraft, two of each kind, sometimes used for redundancy. They are proprietary, custom-built computers built from CMOS and TTL medium-scale CMOS integrated circuits and discrete components, mostly from the 7400 series of Texas Instruments . Total number of words among the six computers is about 32K. Voyager 1 and Voyager 2 have identical computer systems. The Computer Command System (CCS),
5720-529: The Voyagers are still in operation beyond the outer boundary of the heliosphere in interstellar space . Voyager 1 is moving with a velocity of 61,198 kilometers per hour (38,027 mph), or 17 km/s, (10.5 miles/second) relative to the Sun, and is 24,475,900,000 kilometers (1.52086 × 10 mi) from the Sun reaching a distance of 162 AU (24.2 billion km ; 15.1 billion mi ) from Earth as of May 25, 2024. As of 2024, Voyager 2
5824-819: The additional dish antennas available there. Also, in Australia, the Parkes Radio Telescope was brought into the array in time for the fly-by of Neptune in 1989. In the United States, the Very Large Array in New Mexico was brought into temporary use along with the antennas of the Deep Space Network at Goldstone. Using this new technology of antenna arrays helped to compensate for the immense radio distance from Neptune to
5928-474: The cameras. The CCS contains fixed computer programs such as command decoding, fault detection, and correction routines, antenna-pointing routines, and spacecraft sequencing routines. This computer is an improved version of the one that was used in the Viking orbiter . The hardware in both custom-built CCS subsystems in the Voyagers is identical. There is only a minor software modification for one of them that has
6032-476: The central controller of the spacecraft, has two 18-bit word, interrupt-type processors with 4096 words each of non-volatile plated-wire memory . During most of the Voyager mission the two CCS computers on each spacecraft were used non-redundantly to increase the command and processing capability of the spacecraft. The CCS is nearly identical to the system flown on the Viking spacecraft. The Flight Data System (FDS)
6136-427: The chill Martian evening. The Mariner 4 spacecraft, expected to survive something more than the eight months to Mars encounter, actually lasted about three years in solar orbit, continuing long-term studies of the solar wind environment and making coordinated measurements with Mariner 5, a sister ship launched to Venus in 1967. Status: The Mariner 5 spacecraft was launched to Venus on June 14, 1967, and arrived in
6240-466: The craft were between Saturn and Uranus the onboard software was upgraded to do a degree of image compression and to use a more efficient Reed-Solomon error-correcting encoding . Then between 1986 and 1989, new techniques were brought into play to combine the signals from multiple antennas on the ground into one, more powerful signal, in a kind of an antenna array . This was done at Goldstone, California , Canberra (Australia) , and Madrid (Spain) using
6344-513: The dark features long seen from Earth, but no canals. Status: Both Mariner 6 and Mariner 7 are now defunct and are in a heliocentric orbit . Mariner 8 and Mariner 9 were identical sister craft designed to map the Martian surface simultaneously, but Mariner 8 was lost in a launch vehicle failure. Mariner 9 was launched in May 1971 and became the first artificial satellite of Mars. Its launch mass
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#17327726981106448-428: The data for transmission . The DTR is used to record high-rate Plasma Wave Subsystem (PWS) data, which is played back every six months. The Imaging Science Subsystem made up of a wide-angle and a narrow-angle camera is a modified version of the slow scan vidicon camera designs that were used in the earlier Mariner flights. The Imaging Science Subsystem consists of two television-type cameras, each with eight filters in
6552-495: The heliosheath (90–1000 AU). The NASA probe New Horizons may explore this area now that it has performed its Pluto flyby in 2015 (Pluto's orbit ranges from about 29–49 AU). Some of these large objects past Pluto include 136199 Eris , 136108 Haumea , 136472 Makemake , and 90377 Sedna . Sedna comes as close as 76 AU, but travels out as far as 961 AU at aphelion, and minor planet (87269) 2000 OO 67 goes out past 1060 AU at aphelion. Bodies like these affect how
6656-432: The heliosheath is not smooth, but filled with giant magnetic bubbles, theorized to form when the magnetic field of the Sun becomes warped at the edge of the Solar System. In June 2012, Scientists at NASA reported that Voyager 1 was very close to entering interstellar space, indicated by a sharp rise in high-energy particles from outside the Solar System. In September 2013, NASA announced that Voyager 1 had crossed
6760-402: The inner Solar System – visiting the planets Venus , Mars and Mercury for the first time, and returning to Venus and Mars for additional close observations. The program included a number of interplanetary firsts, including the first planetary flyby , the planetary orbiter , and the first gravity assist maneuver. Of the 10 vehicles in the Mariner series, seven were successful, forming
6864-592: The intention to research the heliosphere. Both probes would use gravity assists at Jupiter and fly by Kuiper belt objects , and the second is also planned to fly by Neptune and Triton. The other goal is to reach 100 AU from the Sun by 2049, the centennial of the People's Republic of China's foundation. A NASA funded study, led by the Applied Physics Laboratory , on possible options for an interstellar probe. The nominal concept would launch on
6968-588: The last five used the Atlas-Centaur . All Mariner-based probes after Mariner 10 used the Titan IIIE , Titan IV uncrewed rockets or the Space Shuttle with a solid-fueled Inertial Upper Stage and multiple planetary flybys. The Mariners were all relatively small robotic explorers, each launched on an Atlas rocket with either an Agena or Centaur upper-stage booster, and weighing less than half
7072-604: The late 1960s and early 70s that aimed to explore Jupiter , Saturn , Saturn's moon , Titan , Uranus , Neptune , and Pluto . The mission originated from the Grand Tour program , conceptualized by Gary Flandro , an aerospace engineer at the Jet Propulsion Laboratory, in 1964, which leveraged a rare planetary alignment occurring once every 175 years. This alignment allowed a craft to reach all outer planets using gravitational assists . The mission
7176-612: The magnetometer science data. The two spacecraft continue to operate, with some loss in subsystem redundancy but retain the capability to return scientific data from a full complement of Voyager Interstellar Mission (VIM) science instruments. Both spacecraft also have adequate electrical power and attitude control propellant to continue operating until around 2025, after which there may not be electrical power to support science instrument operation; science data return and spacecraft operations will cease. Interstellar probe As of 2024, there are five interstellar probes, all launched by
7280-493: The most widely separated human-made objects anywhere since they are travelling in roughly opposite directions from the Solar System . In December 2004, Voyager 1 crossed the termination shock , where the solar wind is slowed to subsonic speed, and entered the heliosheath , where the solar wind is compressed and made turbulent due to interactions with the interstellar medium . On 10 December 2007, Voyager 2 also reached
7384-473: The plane of the ecliptic, ending its planetary science mission. Had Voyager 1 been unable to perform the Titan flyby, the trajectory of Voyager 2 could have been altered to explore Titan, forgoing any visit to Uranus and Neptune. Voyager 1 was not launched on a trajectory that would have allowed it to continue to Uranus and Neptune, but could have continued from Saturn to Pluto without exploring Titan. During
7488-508: The planet with infrared and microwave radiometers, revealing that Venus has cool clouds and an extremely hot surface (because the bright, opaque clouds hide the planet's surface, Mariner 2 was not outfitted with a camera). Status: Sisterships Mariner 3 and Mariner 4 were Mars flyby missions. Mariner 3 was launched on November 5, 1964, but the shroud encasing the spacecraft atop its rocket failed to open properly and Mariner 3 did not get to Mars. Mariner 4, launched on November 28, 1964,
7592-450: The planet, covering half the globe (Mercury's slow rotation left the other half always in the dark when Mariner returned). Status: Mariner 10 – Defunct and now in a heliocentric orbit . Mariner Jupiter-Saturn was approved in 1972 after the cancellation of the Grand Tour program , which proposed visiting all the outer planets with multiple spacecraft. The Mariner Jupiter-Saturn program proposed two Mariner-derived probes that would perform
7696-447: The probes to about 15% or 20% of the speed of light, resulting in a travel time of between 20 and 30 years. Geoffrey A. Landis proposed for interstellar travel future-technology project interstellar probe with supplying the energy from an external source ( laser of base station) and ion thruster. In the early 2000s many new, relatively large planetary bodies were found beyond Pluto, and with orbits extending hundreds of AU out past
7800-529: The probes will be under the influence of the Sun for a long time, their velocities far exceed the Sun's escape velocity , so they are leaving forever. Interstellar space is defined as the space beyond a magnetic region that extends about 122 AU from the Sun, as detected by Voyager 1, and the equivalent region of influence surrounding other stars. Voyager 1 entered interstellar space in 2012. Currently, three projects are under consideration: CNSA's Shensuo , NASA's Interstellar Probe , and StarChip from
7904-456: The probes would continue to drift into interstellar space. Voyager 2 was the first to be launched. Its trajectory was designed to allow flybys of Jupiter, Saturn, Uranus, and Neptune. Voyager 1 was launched after Voyager 2 , but along a shorter and faster trajectory that was designed to provide an optimal flyby of Saturn's moon Titan , which was known to be quite large and to possess a dense atmosphere. This encounter sent Voyager 1 out of
8008-563: The scan platform. The custom-built AACS systems on both craft are identical. It has been erroneously reported on the Internet that the Voyager space probes were controlled by a version of the RCA ;1802 (RCA CDP1802 "COSMAC" microprocessor ), but such claims are not supported by the primary design documents. The CDP1802 microprocessor was used later in the Galileo space probe , which
8112-413: The solar wind, a constant stream of charged particles flowing outward from the Sun. It also measured interplanetary dust, which turned out to be more scarce than predicted. In addition, Mariner 2 detected high-energy charged particles coming from the Sun, including several brief solar flares, as well as cosmic rays from outside the Solar System . As it flew by Venus on December 14, 1962, Mariner 2 scanned
8216-475: The spacecraft used a digital tape-recorder rather than film to store images and other science data. The spacecraft was thus able to wait until the storm abated, the dust settled and the surface was clearly visible before compiling its global mosaic of high-quality images of the surface of Mars. It also provided the first closeup pictures of Mars’ two small, irregular moons, Phobos and Deimos. Status: The Mariner 10 spacecraft launched on November 3, 1973, and
8320-477: The stagnation region is located approximately 113 astronomical units (AU) from the Sun. In 2013 it was thought Voyager 1 crossed the heliopause and entered interstellar space on August 25, 2012 at distance of 121 AU from the Sun, making it the first known human-manufactured object to do so. As of 2017 , the probe was moving with a relative velocity to the Sun of about 16.95 km/s (3.58 AU/year). If it does not hit anything, Voyager 1 could reach
8424-408: The star Epsilon Eridani after 3400 years of travel in the year 5500 AD. However, this was a second-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 at about 3.6 AU/year (17 km/s), relative to the Sun. Interstellar Probe
8528-535: The starting point for many subsequent NASA/JPL space probe programs. The planned Mariner Jupiter-Saturn vehicles were adapted into the Voyager program , while the Viking program orbiters were enlarged versions of the Mariner 9 spacecraft. Later Mariner-based spacecraft include Galileo and Magellan , while the second-generation Mariner Mark II series evolved into the Cassini–Huygens probe. The total cost of
8632-401: The termination shock, about 1.6 billion kilometres (1 billion miles) closer to the Sun than from where Voyager 1 first crossed it, indicating that the Solar System is asymmetrical . In 2010 Voyager 1 reported that the outward velocity of the solar wind had dropped to zero, and scientists predicted it was nearing interstellar space . In 2011, data from the Voyagers determined that
8736-433: The thermal power generated by such an RTG would be reduced to (1/2) ≈ 76% of its initial power. The RTG thermocouples , which convert thermal power into electricity, also degrade over time reducing available electric power below this calculated level. By 7 October 2011 the power generated by Voyager 1 and Voyager 2 had dropped to 267.9 W and 269.2 W respectively, about 57% of the power at launch. The level of power output
8840-673: The two Imaging Science Subsystem (ISS) vidicon cameras to the left of the UVS; and the Photopolarimeter System (PPS) under the ISS. Only five investigation teams are still supported, though data is collected for two additional instruments. The Flight Data Subsystem (FDS) and a single eight-track digital tape recorder (DTR) provide the data handling functions. The FDS configures each instrument and controls instrument operations. It also collects engineering and science data and formats
8944-427: The two Voyagers have been carried out using their 3.7-meter (12 ft) high-gain antennas. The high-gain antenna has a beamwidth of 0.5° for X-band, and 2.3° for S-band. (The low-gain antenna has a 7 dB gain and 60° beamwidth.) Because of the inverse-square law in radio communications , the digital data rates used in the downlinks from the Voyagers have been continually decreasing the farther that they get from
9048-418: The vicinity of the planet in October 1967. It carried a complement of experiments to probe Venus ' atmosphere with radio waves , scan its brightness in ultraviolet light , and sample the solar particles and magnetic field fluctuations above the planet. Status: Mariner 5 – Defunct and now in a heliocentric orbit . Mariners 6 and 7 were identical teammates in a two-spacecraft mission to Mars. Mariner 6
9152-497: Was 9.37 AU from the Sun and traveling outward at 3.9 AU per year. It will, however, 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. On July 14, 2015, it completed a flyby of Pluto at a distance of about 33 AU from the Sun. New Horizons next encountered 486958 Arrokoth on January 1, 2019, at about 43.4 AU from
9256-419: Was a novel spacecraft design, proposed by Johndale C. Solem, using a large lightweight sail (spinnaker) driven by pressure pulses from a series of nuclear explosions . The design, published by the British Interplanetary Society , was studied during the 1990s as a means of interplanetary travel. Starseed launcher was concept for launching microgram interstellar probes at up to 1/3 light speed. AIMStar
9360-449: Was a proposed antimatter catalyzed nuclear pulse propulsion craft that would use clouds of antiprotons 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 from the Sun in 50 years. Project Icarus
9464-411: Was a proposed solar sail propulsion spacecraft planned by NASA Jet Propulsion Laboratory. It was planned to reach as far as 200 AU within 15 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/m solar sail. TAU mission (Thousand Astronomical Units) was a proposed nuclear electric rocket craft that used
9568-400: Was better than pre-launch predictions based on a conservative thermocouple degradation model. As the electrical power decreases, spacecraft loads must be turned off, eliminating some capabilities. There may be insufficient power for communications by 2032. The Voyager primary mission was completed in 1989, with the close flyby of Neptune by Voyager 2 . The Voyager Interstellar Mission (VIM) is
9672-493: Was decided to send Voyager 2 on flybys of Uranus and Neptune . After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from Voyager 2 indicated that it also had entered interstellar space. On 4 November 2019, scientists reported that on 5 November 2018,
9776-420: Was designed and built years later. The digital control electronics of the Voyagers were not based on a microprocessor integrated-circuit chip. The uplink communications are executed via S-band microwave communications . The downlink communications are carried out by an X-band microwave transmitter on board the spacecraft, with an S-band transmitter as a back-up. All long-range communications to and from
9880-494: Was destroyed approximately 5 minutes after liftoff by the Air Force Range Safety Officer when its malfunctioning Atlas-Agena rocket went off course. Mariner 2 (designated Mariner R-2) was launched on August 27, 1962, sending it on a 3½-month flight to Venus. The mission was a success, and Mariner 2 became the first spacecraft to have flown by another planet. On the way it measured for the first time
9984-445: Was launched on February 24, 1969, followed by Mariner 7 on March 21, 1969. They flew over the equator and southern hemisphere of the planet Mars . They analyzed atmosphere and surface with remote sensors as well as recording and relaying hundreds of pictures. By chance, both flew over cratered regions and missed both the giant northern volcanoes and the equatorial grand canyon discovered later. Their approach pictures did, however, show
10088-521: Was nearly doubled by the onboard rocket propellant needed to thrust it into orbit around Mars, but otherwise it closely resembled its predecessors. It entered Martian orbit in November 1971 and began photographing the surface and analyzing the atmosphere with its infrared and ultraviolet instruments. Since 1969, Mariner spacecraft operations such as science sequencing and pointing had been programmable, using simple flight computers with limited memory, and
10192-481: Was not appropriate as the mission had differed significantly from previous Mariner missions. Voyager was chosen as the new name, referencing an earlier suggestion by William Pickering , who had proposed the name Navigator . Due to the name change occurring close to launch, the probes were still occasionally referred to as Mariner 11 and Mariner 12, or even Voyager 11 and Voyager 12. Two mission trajectories were established: JST aimed at Jupiter, Saturn, and enhancing
10296-456: Was on April 27, 2002, when it was at a distance of 80.22 AU, and the last signal from the spacecraft was received on January 23, 2003, at a distance 82 AU from the Sun traveling at about 2.54 AU/year (12 km/s). 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/s). New Horizons' third stage,
10400-410: Was scheduled to go off-line in late 2000 but has been left on to investigate UV emission from the upwind direction. UVS data are still captured but scans are no longer possible. Gyro operations ended in 2016 for Voyager 2 and in 2017 for Voyager 1 . Gyro operations are used to rotate the probe 360 degrees six times per year to measure the magnetic field of the spacecraft, which is then subtracted from
10504-475: Was the first successful flyby of the planet Mars and gave the first glimpse of Mars at close range. The spacecraft flew past Mars on July 14, 1965, collecting the first close-up photographs of another planet. The pictures, played back from a small tape recorder over a long period, showed lunar-type impact craters (just beginning to be photographed at close range from the Moon), some of them touched with frost in
10608-473: Was the first to use a gravity assist trajectory, accelerating as it entered the gravitational influence of Venus, then being flung by the planet's gravity onto a slightly different course to reach Mercury. It was also the first spacecraft to encounter two planets at close range, and for 33 years the only spacecraft to photograph Mercury in closeup. Here a fortuitous gravity assist enabled the spacecraft to return at six-month intervals for close mapping passes over
10712-408: Was to develop and launch two spacecraft sequentially to the near vicinity of Venus, receive communications from the spacecraft and to perform radiometric temperature measurements of the planet. A secondary objective was to make interplanetary magnetic field and/or particle measurements on the way to, and in the vicinity of, Venus. Mariner 1 (designated Mariner R-1) was launched on July 22, 1962, but
10816-775: Was to send several pairs of probes and gained momentum in 1966 when it was endorsed by NASA 's Jet Propulsion Laboratory . However, in December 1971, the Grand Tour mission was canceled when funding was redirected to the Space Shuttle program . In 1972, a scaled-down (four planets, two identical spacecraft) mission was proposed, utilizing a spacecraft derived from the Mariner series, initially intended to be Mariner 11 and Mariner 12 . The gravity-assist technique, successfully demonstrated by Mariner 10 , would be used to achieve significant velocity changes by maneuvering through an intermediate planet's gravitational field to minimize time towards Saturn. The spacecrafts were then moved into
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