Voyager 1 is aspace probe launched byNASA on September 5, 1977, as part of theVoyager program, to study the outerSolar System and theinterstellar space beyond the Sun'sheliosphere. It was launched 16 days after its twin,Voyager 2. It communicates through theNASA Deep Space Network (DSN) to receive routine commands and to transmit data to Earth. Real-time distance and velocity data are provided byNASA andJPL.[4] At a distance of 169.27 AU (25.3 billion km; 15.7 billion mi) as of October 2025[update],[4] it is the most distant human-made object from Earth.[5]Voyager 1 is also projected to reach a distance of onelight day from Earth in November of 2026.[6]
The probe madeflybys ofJupiter,Saturn, and Saturn's largestmoon,Titan. NASA had a choice of either conducting aPluto or Titan flyby. Exploration of Titan took priority because it was known to have a substantial atmosphere.[7][8][9]Voyager 1 studied the weather,magnetic fields, and rings of the two gas giants and was the first probe to provide detailed images of their moons.
As part of theVoyager program and like its sister craftVoyager 2, the spacecraft's extended mission is to locate and study the regions and boundaries of the outer heliosphere and to begin exploring the interstellar medium.Voyager 1 crossed theheliopause and enteredinterstellar space on August 25, 2012, making it the first spacecraft to do so.[10][11] Two years later,Voyager 1 began experiencing a third wave ofcoronal mass ejections from the Sun that continued to at least December 15, 2014, further confirming that the probe is in interstellar space.[12]
In 2017, the Voyager team successfully fired the spacecraft's trajectory correction maneuver (TCM) thrusters for the first time since 1980, enabling the mission to be extended by two to three years.[13]
Voyager 1 experienced two successful revivals of several thrusters: In 2018-2019 then in 2025.[14]
Voyager 1's extended mission is expected to continue to return scientific data for several more years.[15] Itsradioisotope thermoelectric generators (RTGs) may supply enough electric power to return engineering data until 2036.[16]
A 1960s proposal for aGrand Tour to study the outer planets led NASA to begin work on a mission during the early 1970s.[17] Initially,Voyager 1 was planned asMariner 11 of theMariner program. Due to budget cuts, the mission was reduced to a flyby of Jupiter and Saturn and renamed theMariner Jupiter-Saturn probes. The name was changed toVoyager when the probe designs began to differ substantially from Mariner missions.[18]
Voyager 1 was built by theJet Propulsion Laboratory (JPL). It has abus shaped like a decagonal (ten-sided) prism. It has 16hydrazine thrusters,three-axis stabilizationgyroscopes, andreferencing instruments to keep the probe's radio antenna pointed towardEarth. Collectively, these instruments are part of the Attitude and Articulation Control Subsystem (AACS), along with redundant units of most instruments and eight backup thrusters.[19] The spacecraft also included 11 scientific instruments to study celestial objects such asplanets as it travels through space.[20]
The radiocommunication system ofVoyager 1 was designed to be used up to and beyond the limits of theSolar System. It has a 3.7-meter (12 ft)diameterhigh-gainCassegrain antenna to send and receiveradio waves via the threeDeep Space Network stations on the Earth.[21] The spacecraft normally transmits data to Earth over Deep Space Network Channel 18, using a frequency of either 2.3 GHz or 8.4 GHz, while signals from Earth to Voyager are transmitted at 2.1 GHz.[22]
WhenVoyager 1 is unable to communicate with the Earth, its digitaltape recorder (DTR) can record about 64 megabytes of data for later transmission.[23] As of 2025[update], signals fromVoyager 1 took more than 23 hours to reach Earth.[4]
Diagram of RTG fuel container, showingplutonium-238 oxide spheres
Voyager 1 has threeradioisotope thermoelectric generators (RTGs) mounted on a boom. EachMHW-RTG contains 24 pressedplutonium-238 PuO2 oxide spheres.[24] The RTGs generated about 470W ofelectric power at the time of launch, with the remainder being dissipated as waste heat.[25] The power output of the RTGs declines over time due to the 87.7-yearhalf-life of the fuel and degradation of thethermocouples, but they will continue to support some of its operations until at least 2025.[20][24]
UnlikeVoyager's other instruments, the operation of the cameras forvisible light is not autonomous, but is controlled by an imaging parameter table contained in one of thedigital computers, the Flight Data Subsystem (FDS). Since the 1990s, most space probes have been equipped with completely autonomous cameras.[26]
The computer command subsystem (CCS) controls the cameras. The CCS contains fixed computer programs, such as command decoding, fault-detection and fault-correction routines, antenna pointing routines, and spacecraft sequencing routines. This computer is an improved version of the one that was used in the 1970sViking orbiters.[27]
The Attitude and Articulation Control Subsystem (AACS) controls thespacecraft orientation. It keeps thehigh-gain antenna pointing towards Earth, controls attitude changes, and points the scan platform. The custom-built AACS systems on both Voyagers are the same.[28][29]
Principal investigator: Bradford Smith / University of Arizona (PDS/PRN website)
Data: PDS/PDI data catalog, PDS/PRN data catalog
Radio Science System (disabled)
(RSS)
Used the telecommunications system of the Voyager spacecraft to determine the physical properties of planets and satellites (ionospheres, atmospheres, masses, gravity fields, densities) and the amount and size distribution of material in Saturn's rings and the ring dimensions.
Principal investigator: G. Tyler / Stanford University PDS/PRN overview
Data: PDS/PPI data catalog, PDS/PRN data catalog (VG_2803), NSSDC data archive
Investigates both global and local energy balance and atmospheric composition. Vertical temperature profiles are also obtained from the planets and satellites as well as the composition, thermal properties, and size of particles inSaturn's rings.
Principal investigator: Rudolf Hanel / NASA Goddard Space Flight Center (PDS/PRN website)
Data: PDS/PRN data catalog, PDS/PRN expanded data catalog (VGIRIS_0001, VGIRIS_002), NSSDC Jupiter data archive
Determines the origin and acceleration process, life history, and dynamic contribution of interstellar cosmic rays, the nucleosynthesis of elements in cosmic-ray sources, the behavior ofcosmic rays in theinterplanetary medium, and the trapped planetary energetic-particle environment.
Principal investigator:Edward Stone / Caltech / NASA Goddard Space Flight Center (website)
Used a telescope with apolarizer to gather information on surface texture and composition of Jupiter and Saturn and information on atmospheric scattering properties and density for both planets.
Principal investigator: Arthur Lane / JPL (PDS/PRN website)
Provides continuous, sheath-independent measurements of the electron-density profiles at Jupiter and Saturn as well as basic information on local wave–particle interaction, useful in studying the magnetospheres.
Principal investigator: William Kurth / University of Iowa (website)
Voyager 1overtakesPioneer 10 as the most distant spacecraft from theSun, at 69.419 AU.Voyager 1 is moving away from the Sun at over 1 AU per year faster thanPioneer 10.
Voyager 1 lifted off atop aTitan IIIE.An animation ofVoyager 1's trajectory from September 1977 to December 31, 1981 Voyager 1·Earth·Jupiter·Saturn·Sun
Voyager 1's launch almost failed because Titan's LR-91 second stage shut down prematurely, leaving 1,200 pounds (540 kg) of propellant unburned. Recognizing the deficiency, the Centaur stage's on-board computers ordered a burn that was far longer than planned in order to compensate. Centaur extended its own burn and was able to giveVoyager 1 the additional velocity it needed.[40]
At cutoff, the Centaur was only 3.4 seconds from propellant exhaustion. If the same failure had occurred duringVoyager 2's launch a few weeks earlier, the Centaur would have run out of propellant before the probe reached the correct trajectory. Jupiter was in a more favorable position vis-à-vis Earth during the launch ofVoyager 1 than during the launch ofVoyager 2.[40]
Voyager 1's initial orbit had an aphelion of 8.9 AU (830 million mi), just a little short of Saturn's orbit of 9.5 AU (880 million mi).Voyager 2's initial orbit had an aphelion of 6.2 AU (580 million mi), well short of Saturn's orbit.[41]
An animation ofVoyager 1's trajectory around Jupiter Voyager 1· Jupiter· Io· Europa· Ganymede· CallistoJupiter'sGreat Red Spot as seen fromVoyager 1
Voyager 1 began photographingJupiter in January 1979. Its closest approach to Jupiter was on March 5, 1979, at a distance of about 349,000 kilometers (217,000 miles) from the planet's center.[38] Because of the greater photographic resolution allowed by a closer approach, most observations of the moons, rings, magnetic fields, and theradiation belt environment of the Jovian system were made during the 48-hour period that bracketed the closest approach. Voyager 1 finished photographing the Jovian system in April 1979.[42]
Information gathered by thePioneer 10 spacecraft helped engineers designVoyager to better cope with the intense radiation around Jupiter.[43] Still, shortly before launch, strips of kitchen-gradealuminium foil were applied to certain cables to improve radiation shielding.[44]
The discovery of ongoing volcanic activity on the moonIo was probably the greatest surprise. It was the first time active volcanoes had been seen on another body in the Solar System. It appears that activity on Io affects the entireJovian system. Io appears to be the primary source of matter that pervades the Jovian magnetosphere – the region of space that surrounds the planet influenced by the planet's strongmagnetic field.Sulfur,oxygen, andsodium, apparently erupted by Io's volcanoes and sputtered off the surface by the impact of high-energy particles, were detected at the outer edge of themagnetosphere of Jupiter.[38]
The two Voyager space probes made a number of important discoveries about Jupiter, its satellites, its radiation belts, and its never-before-seenplanetary rings.
The gravitational assist trajectories at Jupiter were successfully carried out by both Voyagers, and the two spacecraft went on to visitSaturn and its system of moons and rings.Voyager 1 encountered Saturn in November 1980, with the closest approach on November 12, 1980, when the space probe came within 124,000 kilometers (77,000 mi) of Saturn's cloud-tops. The space probe's cameras detected complex structures in therings of Saturn, and itsremote sensing instruments studied the atmospheres of Saturn and its giant moonTitan.[45]
Voyager 1 found that about seven percent of the volume of Saturn's upper atmosphere ishelium (compared with 11 percent of Jupiter's atmosphere), while almost all the rest ishydrogen. Since Saturn's internal helium abundance was expected to be the same as Jupiter's and the Sun's, the lower abundance of helium in the upper atmosphere may imply that the heavier helium may be slowly sinking through Saturn's hydrogen; that might explain the excess heat that Saturn radiates over energy it receives from the Sun. Winds blow at high speeds on Saturn. Near the equator, the Voyagers measured winds about 500 m/s (1,100 mph). The wind blows mostly in an easterly direction.[39]
The Voyagers foundaurora-likeultraviolet emissions ofhydrogen at mid-latitudes in the atmosphere, and auroras at polar latitudes (above 65 degrees). The high-level auroral activity may lead to the formation of complexhydrocarbon molecules that are carried toward theequator. The mid-latitude auroras, which occur only in sunlit regions, remain a puzzle, since bombardment by electrons and ions, known to cause auroras on Earth, occurs primarily at high latitudes. Both Voyagers measured therotation of Saturn (the length of a day) at 10 hours, 39 minutes, 24 seconds.[45]
An animation ofVoyager 1 around Saturn Voyager 1· Saturn· Mimas· Enceladus· Tethys·Rhea·Titan
Voyager 1's mission included a flyby of Titan, Saturn's largest moon, which had long been known to have an atmosphere. Images taken byPioneer 11 in 1979 had indicated the atmosphere was substantial and complex, further increasing interest. The Titan flyby occurred as the spacecraft entered the system to avoid any possibility of damage closer to Saturn compromising observations, and approached to within 6,400 km (4,000 mi), passing behind Titan as seen from Earth and the Sun.[46]
Voyager's measurement of the atmosphere's effect on sunlight and Earth-based measurement of its effect on the probe's radio signal were used to determine the atmosphere's composition, density, and pressure. Titan's mass was also measured by observing its effect on the probe's trajectory. The thick haze prevented any visual observation of the surface, but the measurement of the atmosphere's composition, temperature, and pressure led to speculation that lakes of liquid hydrocarbons could exist on the surface.[46]
Because observations of Titan were considered vital, the trajectory chosen forVoyager 1 was designed around the optimum Titan flyby, which took it below the south pole of Saturn and out of the plane of theecliptic, ending its planetary science mission.[47] HadVoyager 1 failed or been unable to observe Titan,Voyager 2's trajectory would have been altered to incorporate the Titan flyby,[46]: 94 precluding any visit to Uranus and Neptune.[7] The trajectoryVoyager 1 was launched into would not have allowed it to continue on to Uranus and Neptune,[47]: 155 but could have been altered to avoid a Titan flyby and travel from Saturn toPluto, arriving in 1986.[9]
CrescentSaturn from 5.3 million km, four days after closest approach
Voyager 1 image ofSaturn's narrow, twisted and braidedF Ring.
Mimas at a range of 425,000 km. The craterHerschel is at upper right
TheFamily Portrait of the Solar System acquired byVoyager 1, February 14, 1990The position ofVoyager 1 above the plane of the ecliptic on February 14, 1990, the dayFamily Portrait was taken.Voyager 1 and2 speed and distance from the SunThePale Blue Dot image showing Earth from 6 billion kilometers (3.7 billion miles) appearing as a tiny dot (the bluish-white speck approximately halfway down the light band to the right) within the darkness of deep space.[48]
On February 14, 1990,Voyager 1 took the first "family portrait" of the Solar System as seen from outside,[49] which includes the image of planet Earth known asPale Blue Dot. Soon afterward, its cameras were deactivated to conserve energy and computer resources for other equipment. The camera software has been removed from the spacecraft, so it would now be complex to get them working again. Earth-side software and computers for reading the images are also no longer available.[7]
On February 17, 1998,Voyager 1 reached a distance of 69 AU (6.4 billion mi; 10.3 billion km) from the Sun and overtookPioneer 10 as the most distant spacecraft from Earth.[50][51] Traveling at about 17 km/s (11 mi/s), it has the fastest heliocentricrecession speed of any spacecraft.[52]
AsVoyager 1 headed for interstellar space, its instruments continued to study the Solar System. Jet Propulsion Laboratory scientists used theplasma wave experiments aboardVoyager 1 and2 to look for theheliopause, the boundary at which thesolar wind transitions into theinterstellar medium.[53] As of 2013[update], the probe was moving with a relative velocity to the Sun of about 61,197 kilometers per hour (38,026 mph).[4]With the velocity the probe is currently maintaining,Voyager 1 is traveling about 523 million km (325 million mi) per year,[54] or about onelight-year per 18,000 years.
Close flybys of gas giants gavegravity assists to both Voyagers
Scientists at theJohns Hopkins UniversityApplied Physics Laboratory believe thatVoyager 1 entered thetermination shock in February 2003.[55] This marks the point where the solar wind slows to subsonic speeds. Some other scientists expressed doubt and discussed this in the journalNature of November 6, 2003.[56] The issue would not be resolved until other data became available, sinceVoyager 1's solar-wind detector ceased functioning in 1990. This failure meant that termination shock detection would have to be inferred from the data from the other instruments on board.[57][58][59]
In May 2005, a NASA press release said that the consensus was thatVoyager 1 was then in theheliosheath.[60] In a scientific session at theAmerican Geophysical Union meeting inNew Orleans on May 25, 2005,Ed Stone presented evidence that the craft crossed the termination shock in late 2004.[61] This event is estimated to have occurred on December 15, 2004, at a distance of 94 AU (8,700 million mi) from the Sun.[61][62]
On March 31, 2006,amateur radio operators fromAMSAT in Germany tracked and received radio waves fromVoyager 1 using the 20-meter (66 ft) dish atBochum with a long integration technique. Retrieved data was checked and verified against data from theDeep Space Network station at Madrid, Spain. This seems to be the first such amateur tracking ofVoyager 1.[63]
It was confirmed on December 13, 2010, thatVoyager 1 had passed the reach of the radial outward flow of thesolar wind, as measured by the Low Energy Charged Particle device. It is suspected that solar wind at this distance turns sideways because of interstellar wind pushing against the heliosphere. Since June 2010, detection of solar wind had been consistently at zero, providing conclusive evidence of the event.[64][65] On this date, the spacecraft was approximately 116 AU (17.4 billion km; 10.8 billion mi) from the Sun.[66]
Voyager 1 was commanded to change its orientation to measure the sideways motion of the solar wind at that location in space in March 2011 (~33yr 6mo from launch). A test roll done in February had confirmed the spacecraft's ability to maneuver and reorient itself. The course of the spacecraft was not changed. It rotated 70 degrees counterclockwise with respect to Earth to detect the solar wind. This was the first time the spacecraft had done any major maneuvering since theFamily Portrait photograph of the planets was taken in 1990. After the first roll the spacecraft had no problem in reorienting itself withAlpha Centauri,Voyager 1's guide star, and it resumed sending transmissions back to Earth.Voyager 1 was expected to enter interstellar space "at any time".Voyager 2 was still detecting outward flow of solar wind at that point but it was estimated that in the following months or years it would experience the same conditions asVoyager 1.[67][68]
The spacecraft was reported at 12.44° declination and 17.163 hours right ascension, and at an ecliptic latitude of 34.9° (the ecliptic latitude changes very slowly), placing it in the constellationOphiuchus as observed from the Earth on May 21, 2011.[7]
On December 1, 2011, it was announced thatVoyager 1 had detected the firstLyman-alpha radiation originating from theMilky Way galaxy. Lyman-alpha radiation had previously been detected from other galaxies, but because of interference from the Sun, the radiation from the Milky Way was not detectable.[69]
NASA announced on December 5, 2011, thatVoyager 1 had entered a new region referred to as a "cosmic purgatory". Within this stagnation region, 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 decline by nearly half, while the detection of high-energy electrons from outside increases 100-fold. The inner edge of the stagnation region is located approximately 113 AU from the Sun.[70]
NASA announced in June 2012 that the probe was detecting changes in the environment that were suspected to correlate with arrival at theheliopause.[71]Voyager 1 had reported a marked increase in its detection of charged particles from interstellar space, which are normally deflected by the solar winds within theheliosphere from the Sun. The craft thus began to enter the interstellar medium at the edge of the Solar System.[72]
Voyager 1 became the first spacecraft to cross the heliopause in August 2012, then at a distance of 121 AU (1.12×1010 mi; 1.81×1010 km) from the Sun, although this was not confirmed for another year.[73][74][75][76][77]
As of September 2012, sunlight took 16.89 hours to get toVoyager 1 which was at a distance of 121 AU. Theapparent magnitude of the Sun from the spacecraft was −16.3 (about 30 times brighter than the full Moon).[78] The spacecraft was traveling at 17.043 km/s (10.590 mi/s) relative to the Sun. At this rate, it would need about 17,565 years to travel a singlelight-year.[78] To compare,Proxima Centauri, the closest star to the Sun, is about 4.2 light-years (2.65×105 AU) distant. If the spacecraft was traveling in the direction of that star, it would take 73,775 years to reach it.Voyager 1 is heading in the direction of the constellationOphiuchus.[78]
In late 2012, researchers reported that particle data from the spacecraft suggested that the probe had passed through the heliopause. Measurements from the spacecraft revealed a steady rise since May in collisions with high energy particles (above 70 MeV), which are thought to becosmic rays emanating fromsupernova explosions far beyond the Solar System, with a sharp increase in these collisions in late August. At the same time, in late August, there was a dramatic drop in collisions with low-energy particles, which are thought to originate from the Sun.[79]
Ed Roelof, a space scientist atJohns Hopkins University and principal investigator for the Low-Energy Charged Particle instrument on the spacecraft, declared that "most scientists involved withVoyager 1 would agree that [these two criteria] have been sufficiently satisfied".[79] However, the last criterion for officially declaring thatVoyager 1 had crossed the boundary, the expected change in magnetic field direction (from that of the Sun to that of the interstellar field beyond), had not been observed (the field had changed direction by only 2 degrees),[74] which suggested to some that the nature of the edge of the heliosphere had been misjudged.
On December 3, 2012, Voyager project scientist Ed Stone of theCalifornia Institute of Technology said, "Voyager has discovered a new region of the heliosphere that we had not realized was there. We're still inside, apparently. But the magnetic field now is connected to the outside. So it's like a highway letting particles in and out."[80] The magnetic field in this region was 10 times more intense thanVoyager 1 encountered before the termination shock. It was expected to be the last barrier before the spacecraft exited the Solar System completely and entered interstellar space.[81][82][83]
In March 2013, it was announced thatVoyager 1 might have become the first spacecraft to enterinterstellar space, having detected a marked change in the plasma environment on August 25, 2012. However, until September 12, 2013, it was still an open question as to whether the new region was interstellar space or an unknown region of the Solar System. At that time, the former alternative was officially confirmed.[84][85]
In 2013Voyager 1 was exiting the Solar System at a speed of about 3.6 AU (330 million mi; 540 million km) per year, which is 61,602 km/h, 4.83 times the diameter of Earth (12,742 km) per hour; whereasVoyager 2 is going slower, leaving the Solar System at 3.3 AU (310 million mi; 490 million km) per year.[86] Each year,Voyager 1 increases its lead overVoyager 2.
Voyager 1 reached a distance of 135 AU (12.5 billion mi; 20.2 billion km) from the Sun on May 18, 2016.[4] On September 5, 2017, that had increased to about 139.64 AU (12.980 billion mi; 20.890 billion km) from the Sun, or just over 19 light-hours; at that time,Voyager 2 was 115.32 AU (10.720 billion mi; 17.252 billion km) from the Sun.[4]
Its progress can be monitored at NASA's website.[4][87]
Plot showing a dramatic increase in the rate ofcosmic ray particle detection by theVoyager 1 spacecraft, October 2011 to October 2012
Plot showing a dramatic decrease in the rate ofsolar wind particle detection byVoyager 1, October 2011 to October 2012
Voyager 1 and the other probes that are in or on their way to interstellar space, exceptNew Horizons.Voyager 1 transmitted audio signals generated byplasma waves from interstellar space
On September 12, 2013, NASA officially confirmed thatVoyager 1 had reached theinterstellar medium in August 2012 as previously observed. The generally accepted date of arrival is August 25, 2012 (approximately 10 days before the 35th anniversary of its launch), the date durable changes in the density of energetic particles were first detected.[75][76][77] By this point, most space scientists had abandoned the hypothesis that a change in magnetic field direction must accompany a crossing of the heliopause;[76] a new model of the heliopause predicted that no such change would be found.[88]
A key finding that persuaded many scientists that the heliopause had been crossed was an indirect measurement of an 80-fold increase in electron density, based on the frequency ofplasma oscillations observed beginning on April 9, 2013,[76] triggered by asolar outburst that had occurred in March 2012[73] (electron density is expected to be two orders of magnitude higher outside the heliopause than within).[75]
Weaker sets of oscillations measured in October and November 2012[85][89] provided additional data. An indirect measurement was required becauseVoyager 1's plasma spectrometer had stopped working in 1980.[77] In September 2013, NASA released recordings of audiotransductions of these plasma waves, the first to be measured in interstellar space.[90]
WhileVoyager 1 is commonly spoken of as having left the Solar System simultaneously with having left the heliosphere, the two are not the same. The Solar System is usually defined as the vastly larger region of space populated by bodies that orbit the Sun. The craft is presently less than one-seventh the distance to theaphelion ofSedna, and it has not yet entered theOort cloud, the source region oflong-period comets, regarded by astronomers as the outermost zone of the Solar System.[74][85]
In October 2020, astronomers reported a significant unexpected increase in density in thespace beyond the Solar System as detected by theVoyager 1 andVoyager 2space probes. According to the researchers, this implies that "the density gradient is a large-scale feature of theVLISM (very localinterstellar medium) in the general direction of theheliospheric nose".[91][92]
In May 2021, NASA reported on the continuous measurement, for the first time, of the density of material in interstellar space and, as well, the detection of interstellar sounds for the first time.[93]
In May 2022, NASA reported thatVoyager 1 had begun transmitting "mysterious" and "peculiar"telemetric data to theDeep Space Network (DSN). It confirmed that the operational status of the craft remained unchanged, but that the issue stemmed from the Attitude Articulation and Control System (AACS). NASA's Jet Propulsion Laboratory published a statement on May 18, 2022, that the AACS was functional but sending invalid data.[94][95]
The problem was eventually traced to the AACS sending its telemetry through a computer that had been non-operational for years, resulting in data corruption. In August 2022, NASA transmitted a command to the AACS to use another computer, which resolved the problem. An investigation into what caused the initial switch is underway, though engineers have hypothesized that the AACS had executed a bad command from another onboard computer.[96][97]
Voyager 1 began transmitting unreadable data on November 14, 2023. On December 12, 2023, NASA announced thatVoyager 1's flight data system was unable to use its telemetry modulation unit, preventing it from transmitting scientific data.[98] On March 24, 2024, NASA announced that they had made significant progress on interpreting the data being received from the spacecraft.[99] Engineers reported in April 2024 that the failure was likely in a memory bank of the Flight Data Subsystem (FDS), one of the three onboard computer systems, probably from being struck by a high-energy particle or that it simply wore out due to age. The FDS was not communicating properly with the telemetry modulation unit (TMU), which began transmitting a repeating sequence of ones and zeros indicating that the system was in a stuck condition. After a reboot of the FDS, communications remained unusable.[100]
The probe still received commands from Earth, and was sending a carrier tone indicating it was still operational. Commands sent to alter the modulation of the tone succeeded, confirming that the probe was still responsive.[101] TheVoyager team began developing a workaround,[102][103] and on April 20 communication of health and status was restored by rearranging code away from the defective FDS memory chip, three percent of which was corrupted beyond repair.[36][104]
Because the memory is corrupted, the code needed to be relocated, but there were no place for an extra 256 bits; the spacecraft's total memory is only 68 kilobytes. To make it work, the engineers deleted unused code, for example the code used to transmit the data from Jupiter, that cannot be used at the current transmission rate. All the data from the "anomaly period" is lost.[105] On May 22, NASA announced that Voyager 1 "resumed returning science data from two of its four instruments", with work towards the others ongoing.[106] On June 13, NASA confirmed that the probe returns data from all four instruments.[107]
In October 2024, the probe turned off itsX-band radio transmitter that was used for communications with the DSN. It was caused by the probe's fault protection system that was activated after NASA turned on one of the heaters on October 16. Fault protection system lowered the transmission rate, but the engineers were able to find the signal. Later, on October 19, the transmission stopped; the fault protection system was triggered once again and switched to theS-band transmitter, that was previously used in 1981.[108] NASA reported that the team reactivated the X-band transmitter and then resumed collecting data in mid-November.[109]
Between 4 May 2025 and February 2026, Deep Space Station 43 in Canberra—the only antenna capable of sending commands to Voyager 1 and 2—will be offline for major upgrades, with only limited operational windows in August and December 2025. This created a critical deadline for engineers to revive backup roll thrusters before any full loss of communication.[14]
An image ofVoyager 1's radio signal on February 21, 2013.[111]
In December 2017, NASA successfully fired all four ofVoyager 1's trajectory correction maneuver (TCM) thrusters for the first time since 1980. The TCM thrusters were used in the place of a degraded set of jets to help keep the probe's antenna pointed towards Earth. Using the TCM thrusters allowedVoyager 1 to continue transmitting data to NASA for two to three more years.[112][33]
Due to the diminishing electrical power available, the Voyager team has had to prioritize which instruments to keep on and which to turn off. Heaters and other spacecraft systems have been turned off one by one as part of power management. The fields and particles instruments that are the most likely to send back key data about the heliosphere and interstellar space have been prioritized to keep operating. Engineers expect the spacecraft to continue operating at least one science instrument until around 2025.[113][needs update]
Year
End of specific capabilities as a result of the available electrical power limitations
Termination of Data Tape Recorder (DTR) operations (limited by ability to capture 1.4 kbit/s data using a 70 m/34 m antenna array; this is the minimum rate at which the DTR can read out data).[114]
Unknown date
Termination ofgyroscopic operations (previously 2017, but backup thrusters active for continuation of gyroscopic operations).[114]
2025–2036
Will no longer be able to power even a single instrument. After 2036, both probes will be out of range of theDeep Space Network.[16]
Somethrusters needed to control the attitude of the spacecraft and point its high-gain antenna in the direction of Earth are out of use due to clogging problems in theirhydrazine lines. The spacecraft no longer has a backup available for its thruster system and "everything onboard is single-string," according to Suzanne Dodd, Voyager project manager at JPL, in an interview withArs Technica.[115] NASA has accordingly decided to modify the spacecraft's computer software in order to reduce the rate at which the hydrazine lines clog. NASA will first deploy the modified software onVoyager 2, which is less distant from Earth, before deploying it onVoyager 1.[115]
In September 2024, NASA performed a "thruster swap", switching from a clogged set of thrusters to less clogged ones that had not been used since 2018.[116]
In May 2025, the team was able to revive the backup thrusters used for roll motion that were unusable since 2004.[117]
In about 50,000 yearsVoyager 1 will be as distant as several nearby stars
ProvidedVoyager 1 does not collide with anything and is not retrieved, theNew Horizons space probe will never pass it, despite being launched from Earth at a higher speed than either Voyager spacecraft. The Voyager spacecraft benefited from multiple planetary flybys to increase its heliocentric velocities, whereasNew Horizons received only a single such boost, from its Jupiter flyby in 2007. As of 2018[update],New Horizons is traveling at about 14 km/s (8.7 mi/s), 3 km/s (1.9 mi/s) slower thanVoyager 1, andNew Horizons, being closer to the sun, is slowing more rapidly.[118]
Voyager 1 is expected to reach the theorized Oort cloud in about 300 years[119][120] and take about 30,000 years to pass through it.[74][85] Though it is not heading towards any particular star, in about 40,000 years, it will pass within 1.6light-years (0.49parsecs) of the starGliese 445, which is in the constellationCamelopardalis and 17.1 light-years from Earth (as of 2010).[121] That star is generally moving towards the Solar System at about 119 km/s (430,000 km/h; 270,000 mph).[121] NASA says that "The Voyagers are destined – perhaps eternally – to wander the Milky Way."[122] In 300,000 years, it will pass within less than 1 light-year of the M3V star TYC 3135–52–1.[123]
Both Voyager space probes carry a gold-platedaudio-visual disc, a compilation meant to showcase the diversity of life and culture on Earth in the event that either spacecraft is ever found by any extraterrestrial discoverer.[124][125] The record, made under the direction of a team includingCarl Sagan andTimothy Ferris, includes photos of the Earth and its lifeforms, a range of scientific information, spoken greetings from people such as theSecretary-General of the United Nations (Kurt Waldheim) and a medley, "Sounds of Earth".[126]
It includes the sounds of whales, a baby crying, waves breaking on a shore, and a collection of music spanning different cultures and eras including works byWolfgang Amadeus Mozart,Blind Willie Johnson,Chuck Berry andValya Balkanska. Other Eastern and Western classics are included, as well as performances of indigenous and folk music from around the world. The record also contains greetings in 55 different languages.[126] The project aimed to portray the richness of life on Earth and stand as a testament to human creativity and the desire to connect with the cosmos.[125][32]
^"1960s". JPL. Archived fromthe original on December 8, 2012. RetrievedAugust 18, 2013.
^Mack, Pamela Etter (1998)."11".From Engineering Science to Big Science: The NACA and NASA Collier Trophy Research Project Winners. National Aeronautics and Space Administration, NASA Office of Policy and Plans, NASA History Office. p. 251.ISBN978-0-16-049640-0.
^Ludwig, Roger; Taylor, Jim (March 2002)."Voyager Telecommunications"(PDF).Descanso Design and Performance Summary Series. NASA/JPL.Archived(PDF) from the original on February 15, 2013. RetrievedSeptember 16, 2013.
^HorizonsArchived October 7, 2012, at theWayback Machine, JPL Solar System Dynamics (Ephemeris Type Elements; Target Body: Voyagern (spacecraft); Center: Sun (body center); Time Span:launch + 1 month toJupiter encounter – 1 month)
^"Preview Screening: The Farthest – Voyager in Space".informal.jpl.nasa.gov. NASA Museum Alliance. August 2017.Archived from the original on July 1, 2019. RetrievedAugust 18, 2019.supermarket aluminum foil added at the last minute to protect the craft from radiation
^Krimigis, S.M.; Decker, R.B.; Hill, M.E.; Armstrong, T.P.; Gloeckler, G.; Hamilton, D.C.; Lanzerotti, L.J.; Roelof, E.C. (2003). "Voyager 1 exited the solar wind at a distance of ~85 au from the Sun".Nature.426 (6962):45–48.Bibcode:2003Natur.426...45K.doi:10.1038/nature02068.PMID14603311.S2CID4393867.
^McDonald, Frank B.; Stone, Edward C.; Cummings, Alan C.; Heikkila, Bryant; Lal, Nand; Webber, William R. (2003). "Enhancements of energetic particles near the heliospheric termination shock".Nature.426 (6962):48–51.Bibcode:2003Natur.426...48M.doi:10.1038/nature02066.PMID14603312.S2CID4387317.
Missions are ordered by launch date. Sign† indicates failure en route or before intended mission data returned.‡ indicates use of the planet as agravity assist en route to another destination.
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated inunderline. Uncatalogued launch failures are listed initalics. Payloads deployed from other spacecraft are denoted in (brackets).
.png)
.jpg)
.jpg)
