Voyager 1#Scientific instruments

{{Main|Mariner Jupiter-Saturn}}

A 1960s proposal for a Grand Tour to study the outer planets led NASA to begin work on a mission during the early 1970s.{{Cite web |title=1960s |url=http://voyager.jpl.nasa.gov/mission/index.html |url-status=dead |archive-url=https://web.archive.org/web/20121208070306/http://voyager.jpl.nasa.gov/mission/index.html |archive-date=December 8, 2012 |access-date=August 18, 2013 |publisher=JPL}} Information gathered by the Pioneer 10 spacecraft helped engineers design Voyager to better cope with the intense radiation around Jupiter.{{Cite web |date=2007 |title=The Pioneer missions |url=https://www.nasa.gov/centers/ames/missions/archive/pioneer.html |url-status=live |archive-url=https://web.archive.org/web/20210831073224/https://www.nasa.gov/centers/ames/missions/archive/pioneer.html |archive-date=August 31, 2021 |access-date=August 19, 2013 |publisher=NASA}} Still, shortly before launch, strips of kitchen-grade aluminum foil were applied to certain cables to improve radiation shielding.{{Cite web |last= |date=August 2017 |title=Preview Screening: The Farthest – Voyager in Space |url=https://informal.jpl.nasa.gov/museum/content/preview-screening-farthest-voyager-space |url-status=live |archive-url=https://web.archive.org/web/20190701213014/https://informal.jpl.nasa.gov/museum/content/preview-screening-farthest-voyager-space |archive-date=July 1, 2019 |access-date=August 18, 2019 |website=informal.jpl.nasa.gov |publisher=NASA Museum Alliance |quote=supermarket aluminum foil added at the last minute to protect the craft from radiation}}

Initially, Voyager 1 was planned as Mariner 11 of the Mariner program. Due to budget cuts, the mission was reduced to a flyby of Jupiter and Saturn and renamed the Mariner Jupiter-Saturn probes. The name was changed to Voyager when the probe designs began to differ substantially from Mariner missions.{{Cite book |last=Mack |first=Pamela Etter |title=From Engineering Science to Big Science: The NACA and NASA Collier Trophy Research Project Winners |date=1998 |publisher=National Aeronautics and Space Administration, NASA Office of Policy and Plans, NASA History Office |isbn=978-0-16-049640-0 |page=251 |language=en |chapter=11 |chapter-url=https://books.google.com/books?id=0j-4d73jQFEC&pg=PA251}}

{{Main|Voyager program#Spacecraft design}}

File:Voyager Program - High-gain antenna diagram.png used on the Voyager craft]]

Voyager 1 was built by the Jet Propulsion Laboratory (JPL). It has 16 hydrazine thrusters, three-axis stabilization gyroscopes, and referencing instruments to keep the probe's radio antenna pointed toward Earth. Collectively, these instruments are part of the Attitude and Articulation Control Subsystem (AACS), along with redundant units of most instruments and eight backup thrusters.{{cite web |url=https://starbrite.jpl.nasa.gov/ds-view/pds/viewHostProfile.jsp?INSTRUMENT_HOST_ID=VG2 |title=Voyager 2: Host Information |date=1989 |publisher=NASA |access-date=January 2, 2011 |archive-url=https://web.archive.org/web/20170220172046/https://starbrite.jpl.nasa.gov/ds-view/pds/viewHostProfile.jsp?INSTRUMENT_HOST_ID=VG2 |archive-date=February 20, 2017}} The spacecraft also included 11 scientific instruments to study celestial objects such as planets as it travels through space.{{Cite web |date=1989 |title=Voyager 1: Host Information |url=https://voyager.jpl.nasa.gov/spacecraft/ |url-status=live |archive-url=https://web.archive.org/web/20150416054228/http://voyager.jpl.nasa.gov/spacecraft/ |archive-date=April 16, 2015 |access-date=April 29, 2015 |publisher=JPL}}

The radio communication system of Voyager 1 was designed to be used up to and beyond the limits of the Solar System. It has a {{convert|3.7|m|adj=on|sp=us}} diameter high-gain Cassegrain antenna to send and receive radio waves via the three Deep Space Network stations on the Earth.{{Cite web |title=High Gain Antenna |url=https://voyager.jpl.nasa.gov/spacecraft/instruments_hga.html |url-status=live |archive-url=https://web.archive.org/web/20130921060751/http://voyager.jpl.nasa.gov/spacecraft/instruments_hga.html |archive-date=September 21, 2013 |access-date=August 18, 2013 |publisher=JPL}} 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.{{Cite web |last1=Ludwig |first1=Roger |last2=Taylor |first2=Jim |date=March 2002 |title=Voyager Telecommunications |url=https://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf |url-status=live |archive-url=https://web.archive.org/web/20130215195832/http://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf |archive-date=February 15, 2013 |access-date=September 16, 2013 |website=Descanso Design and Performance Summary Series |publisher=NASA/JPL}}

When Voyager 1 is unable to communicate with the Earth, its digital tape recorder (DTR) can record about 67 kilobytes of data for later transmission.{{Cite web |title=NASA News Press Kit 77–136 |url=http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=9476.0;attach=591860 |url-status=live |archive-url=https://web.archive.org/web/20190529081627/https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=9476.0;attach=591860 |archive-date=May 29, 2019 |access-date=December 15, 2014 |publisher=JPL/NASA}} {{As of|2023}}, signals from Voyager 1 take more than 22 hours to reach Earth.

Voyager 1 has three radioisotope thermoelectric generators (RTGs) mounted on a boom. Each MHW-RTG contains 24 pressed plutonium-238 oxide spheres. The RTGs generated about 470 W of electric power at the time of launch, with the remainder being dissipated as waste heat.{{Cite web |title=Spacecraft Lifetime |url=https://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html |url-status=live |archive-url=https://web.archive.org/web/20170301102317/http://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html |archive-date=March 1, 2017 |access-date=August 19, 2013 |publisher=JPL}} The power output of the RTGs declines over time due to the 87.7-year half-life of the fuel and degradation of the thermocouples, but they will continue to support some of its operations until at least 2025.{{Cite journal |last1=Furlong |first1=Richard R. |last2=Wahlquist |first2=Earl J. |date=1999 |title=U.S. space missions using radioisotope power systems |url=http://www2.ans.org/pubs/magazines/nn/pdfs/1999-4-2.pdf |url-status=dead |journal=Nuclear News |volume=42 |issue=4 |pages=26–34 |archive-url=https://web.archive.org/web/20181016011258/http://www3.ans.org/pubs/magazines/nn/pdfs/1999-4-2.pdf |archive-date=October 16, 2018 |access-date=January 2, 2011}}

File:Voyager Program - RTG diagram 1.png|Diagram of RTG fuel container, showing the plutonium-238 oxide spheres

File:Voyager Program - RTG diagram 2.png|Diagram of RTG shell, showing the power-producing silicon-germanium thermocouples

File:Voyager Program - RTG upclose.png|Model of an RTG unit

Unlike Voyager's other instruments, the operation of the cameras for visible light is not autonomous, but is controlled by an imaging parameter table contained in one of the digital computers, the Flight Data Subsystem (FDS). Since the 1990s, most space probes have been equipped with completely autonomous cameras.{{Cite web |title=pds-rings |url=https://pds-rings.seti.org/voyager/iss/inst_cat_wa1.html |url-status=live |archive-url=https://web.archive.org/web/20211107025433/https://pds-rings.seti.org/voyager/iss/inst_cat_wa1.html |archive-date=November 7, 2021 |access-date=May 23, 2015}}

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 1970s Viking orbiters.{{cite book

|first = James E.

|last = Tomayko

|editor-last1 = Kent

|editor-first1 = Allen

|editor-last2 = Williams

|editor-first2 = James G.

|chapter = Distributed Computing On Board Voyager and Galileo (chapter 6)

|url = https://ntrs.nasa.gov/citations/19880069935

|title = Computers in Spaceflight: The NASA Experience

|series = Encyclopedia of Computer Science and Technology

|chapter-url = https://history.nasa.gov/computers/Ch6-2.html

|publisher = NASA

|bibcode = 1988csne.book.....T

|year = 1987

|isbn = 978-0-8247-2268-5

|volume = 18. Supplement 3

|via = NASA History

|access-date = December 16, 2023

|archive-date = October 18, 2023

|archive-url = https://web.archive.org/web/20231018062947/https://ntrs.nasa.gov/citations/19880069935

|url-status = live

}}

The Attitude and Articulation Control Subsystem (AACS) controls the spacecraft orientation. It keeps the high-gain antenna pointing towards Earth, controls attitude changes, and points the scan platform. The custom-built AACS systems on both Voyagers are the same.{{Cite web |title=au.af |url=http://www.au.af.mil/au/awc/awcgate/jplbasic/bsf11-2.htm |url-status=dead |archive-url=https://web.archive.org/web/20151016052108/http://www.au.af.mil/au/awc/awcgate/jplbasic/bsf11-2.htm |archive-date=October 16, 2015 |access-date=May 23, 2015}}{{Cite web |title=airandspace |url=https://airandspace.si.edu/collections/artifact.cfm?object=nasm_A19990066000 |archive-url=https://web.archive.org/web/20160406141000/http://airandspace.si.edu/collections/artifact.cfm?object=nasm_A19990066000 |archive-date=April 6, 2016 |access-date=May 23, 2015}}

{{Main|Voyager program}}

| style="vertical-align:top;" |

|}

{{unordered list

| style=font-size:85%;

| Principal investigator: Bradford Smith / University of Arizona (PDS/PRN website)

| Data: PDS/PDI data catalog, PDS/PRN data catalog

}}

|-

| {{partial|Radio Science System
{{small|(disabled)}}}}

| (RSS)

| style="text-align:left;" | 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.

{{unordered list

| style=font-size:85%;

| Principal investigator: G. Tyler / Stanford University PDS/PRN overview

| Data: PDS/PPI data catalog, PDS/PRN data catalog (VG_2803), NSSDC data archive

}}

|-

| {{partial|Infrared interferometer spectrometer and radiometer
{{small|(disabled)}}}}

| (IRIS)

| style="text-align:left;" | 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 in Saturn's rings.

{{unordered list

| style=font-size:85%;

| 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

}}

|-

| {{partial|Ultraviolet Spectrometer
{{small|(disabled)}}}}

| (UVS)

| style="text-align:left;" | Designed to measure atmospheric properties, and to measure radiation.

{{unordered list

| style=font-size:85%;

| Principal investigator: A. Broadfoot / University of Southern California (PDS/PRN website)

| Data: PDS/PRN data catalog

}}

|-

| {{yes|Triaxial Fluxgate Magnetometer
{{small|(active)}}}}

| (MAG)

| style="text-align:left;" | Designed to investigate the magnetic fields of Jupiter and Saturn, the interaction of the solar wind with the magnetospheres of these planets, and the magnetic field of interplanetary space out to the boundary between the solar wind and the magnetic field of interstellar space.

{{unordered list

| style=font-size:85%;

| Principal investigator: Norman F. Ness / NASA Goddard Space Flight Center (website)

| Data: PDS/PPI data catalog, NSSDC data archive

}}

|-

| {{no|Plasma Spectrometer
{{small|(defective)}}}}

| (PLS)

| style="text-align:left;" | Investigates the microscopic properties of the plasma ions and measures electrons in the energy range from 5 eV to 1 keV.

{{unordered list

| style=font-size:85%;

| Principal investigator: John Richardson / MIT (website)

| Data: PDS/PPI data catalog, NSSDC data archive

}}

|-

| {{yes|Low Energy Charged Particle Instrument
{{small|(active)}}}}

| (LECP)

| style="text-align:left;" | Measures the differential in energy fluxes and angular distributions of ions, electrons and the differential in energy ion composition.

{{unordered list

| style=font-size:85%;

| Principal investigator: Stamatios Krimigis / JHU / APL / University of Maryland (JHU/APL website / UMD website / KU website)

| Data: UMD data plotting, PDS/PPI data catalog, NSSDC data archive

}}

|-

| {{partial|Cosmic Ray System
{{small|(disabled)}}}}

| (CRS)

| style="text-align:left;" | 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 of cosmic rays in the interplanetary medium, and the trapped planetary energetic-particle environment.

{{unordered list

| style=font-size:85%;

| Principal investigator: Edward Stone / Caltech / NASA Goddard Space Flight Center (website)

| Data: PDS/PPI data catalog, NSSDC data archive

}}

|-

| {{partial|Planetary Radio Astronomy Investigation
{{small|(disabled)}}}}

| (PRA)

| style="text-align:left;" | Uses a sweep-frequency radio receiver to study the radio-emission signals from Jupiter and Saturn.

{{unordered list

| style=font-size:85%;

| Principal investigator: James Warwick / University of Colorado

| Data: PDS/PPI data catalog, NSSDC data archive

}}

|-

| {{no|Photopolarimeter System
{{small|(defective)}}}}

| (PPS)

| style="text-align:left;" | Used a telescope with a polarizer to gather information on surface texture and composition of Jupiter and Saturn and information on atmospheric scattering properties and density for both planets.

{{unordered list

| style=font-size:85%;

| Principal investigator: Arthur Lane / JPL (PDS/PRN website)

| Data: PDS/PRN data catalog

}}

|-

| {{yes|Plasma Wave Subsystem
{{small|(active)}}}}

| (PWS)

| style="text-align:left;" | 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.

{{unordered list

| style=font-size:85%;

| Principal investigator: William Kurth / University of Iowa (website)

| Data: PDS/PPI data catalog

}}

|}

{{Gallery

| align = center

| title = Images of the spacecraft

| width = 175

| mode = packed

| File:Voyager1 Space simulator.gif

| Voyager 1 'Proof Test Model' in a space simulator chamber at JPL 3/12/1976

| File:Record is attached to Voyager 1.jpg

| Gold-Plated Record is attached to Voyager 1

| alt2 = Voyager 1 in the Space Simulator chamber

| File:P39582 2 Ed Stone.jpg

| Edward C. Stone, director of NASA JPL, standing in front of a Voyager spacecraft model

| File:Voyager Instruments.jpg|The location of Voyager's scientific instruments, indicated in a diagram

| alt3 = Gold-Plated Record is attached to Voyager 1

| footer = {{center|{{commons-inline|bullet=none|Category:Voyager spacecraft|the Voyager spacecraft}}}}

}}

{{clear}}

File:Titan 3E with Voyager 1.jpg.]]

File:Animation of Voyager 1 trajectory.gif}}{{·}}{{legend2| Cyan |Jupiter}}{{·}}{{legend2|Lime|Saturn}}{{·}}{{legend2| Yellow |Sun }}]]

The Voyager 1 probe was launched on September 5, 1977, from Launch Complex 41 at the Cape Canaveral Air Force Station, aboard a Titan IIIE launch vehicle. The Voyager 2 probe had been launched two weeks earlier, on August 20, 1977. Despite being launched later, Voyager 1 reached both Jupiter{{Cite web |title=Encounter with Jupiter |url=https://voyager.jpl.nasa.gov/science/jupiter.html |url-status=live |archive-url=https://web.archive.org/web/20130916055701/http://voyager.jpl.nasa.gov/science/jupiter.html |archive-date=September 16, 2013 |access-date=August 18, 2013 |publisher=NASA}} and Saturn sooner, following a shorter trajectory.{{Cite web |title=Planetary voyage |url=https://voyager.jpl.nasa.gov/science/planetary.html |url-status=live |archive-url=https://web.archive.org/web/20130826105129/http://voyager.jpl.nasa.gov/science/planetary.html |archive-date=August 26, 2013 |access-date=August 18, 2013 |publisher=NASA}}

Voyager 1{{'}}s launch almost failed because Titan's LR-91 second stage shut down prematurely, leaving {{convert|1200|lb}} 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 give Voyager 1 the additional velocity it needed.{{Cite web |date=September 5, 2012 |title=Voyager 1 Probe's 35-Year Trek to Interstellar Space Almost Never Was |url=https://www.space.com/17466-voyager-1-spacecraft-solar-system-35th-anniversary.html |url-status=live |archive-url=https://web.archive.org/web/20120906173924/http://www.space.com/17466-voyager-1-spacecraft-solar-system-35th-anniversary.html |archive-date=September 6, 2012 |access-date=September 5, 2012 |publisher=Space.com}}

At cutoff, the Centaur was only 3.4 seconds from propellant exhaustion. If the same failure had occurred during Voyager 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 of Voyager 1 than during the launch of Voyager 2.{{Cite web |date=September 5, 2012 |title=Voyager 1 Probe's 35-Year Trek to Interstellar Space Almost Never Was |url=https://www.space.com/17466-voyager-1-spacecraft-solar-system-35th-anniversary.html |url-status=live |archive-url=https://web.archive.org/web/20120906173924/http://www.space.com/17466-voyager-1-spacecraft-solar-system-35th-anniversary.html |archive-date=September 6, 2012 |access-date=September 5, 2012 |publisher=Space.com}}

Voyager 1{{'s}} initial orbit had an aphelion of {{Convert|8.9|AU|e6mi|abbr=unit}}, just a little short of Saturn's orbit of {{Convert|9.5|AU|e6mi|abbr=unit}}. Voyager 2{{'}}s initial orbit had an aphelion of {{Convert|6.2|AU|e6mi|abbr=unit}}, well short of Saturn's orbit.[https://ssd.jpl.nasa.gov/horizons.cgi Horizons] {{Webarchive|url=https://web.archive.org/web/20121007034731/https://ssd.jpl.nasa.gov/horizons.cgi |date=October 7, 2012 }}, JPL Solar System Dynamics (Ephemeris Type Elements; Target Body: Voyager n (spacecraft); Center: Sun (body center); Time Span: launch + 1 month to Jupiter encounter – 1 month)

{{Main|Exploration of Jupiter}}

File:Animation of Voyager 1 trajectory around Jupiter.gif

File:Voyager-1 Jupiter-flyby March-5-1979.png

Voyager 1 began photographing Jupiter in January 1979. Its closest approach to Jupiter was on March 5, 1979, at a distance of about {{convert|349000|km|mi|abbr=off|sp=us}} from the planet's center. Because of the greater photographic resolution allowed by a closer approach, most observations of the moons, rings, magnetic fields, and the radiation 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.{{Cite web |title=Voyager – Images Voyager took of Jupiter |url=https://voyager.jpl.nasa.gov/galleries/images-voyager-took/jupiter/#:~:text=Photography%20of%20Jupiter%20began%20in,and%20many%20other%20scientific%20measurements. |url-status=live |archive-url=https://web.archive.org/web/20201205001001/https://voyager.jpl.nasa.gov/galleries/images-voyager-took/jupiter/#:~:text=Photography%20of%20Jupiter%20began%20in,and%20many%20other%20scientific%20measurements. |archive-date=December 5, 2020 |access-date=December 23, 2020 |website=voyager.jpl.nasa.gov |language=en}}

The discovery of ongoing volcanic activity on the moon Io 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 entire Jovian 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 strong magnetic field. Sulfur, oxygen, and sodium, 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 the magnetosphere of Jupiter.

The two Voyager space probes made a number of important discoveries about Jupiter, its satellites, its radiation belts, and its never-before-seen planetary rings.

File:Jupiter from Voyager 1 PIA02855 thumbnail 300px max quality.ogv|Voyager 1 time-lapse movie of Jupiter approach (full-size video)

File:Great Red Spot From Voyager 1.jpg|alt=The Great Red Spot as seen from Voyager 1|Jupiter's Great Red Spot, an anti-cyclonic storm larger than Earth, as seen from Voyager 1

File:Volcanic crater with radiating lava flows on Io.jpg|alt=View of lava flows radiating from the volcano Ra Patera on Io|View of sulfur-rich lava flows radiating from the volcano Ra Patera on Io

File:Vulcanic Explosion on Io.jpg|alt=A volcanic eruption plume rises over the limb of Io|The eruption plume of the volcano Loki rises {{convert|160|km|sigfig=1|abbr=on}} over the limb of Io

File:PIA01970.jpg|alt=Europa as seen from Voyager 1 at a distance of 2.8 million km|Europa's lineated but un-cratered face, evidence of currently active geology, at a distance of 2.8 million km.

File:Ganymede - PIA02278.jpg|alt=Icy surface of Ganymede as photographed from 253,000 km|Ganymede's tectonically disrupted surface, marked with bright impact sites, from 253,000 km.

{{center|{{commons-inline|bullet=none|Category:Photos of Jupiter system by Voyager 1|the Voyager 1 Jupiter encounter}}}}

File:Animation of Voyager 1 around Saturn.gif}}{{·}}{{legend2|RoyalBlue|Titan}}]]

{{Main|Exploration of Saturn}}

The gravitational assist trajectories at Jupiter were successfully carried out by both Voyagers, and the two spacecraft went on to visit Saturn 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 {{convert|124000|km|mi|-3|sp=us}} of Saturn's cloud-tops. The space probe's cameras detected complex structures in the rings of Saturn, and its remote sensing instruments studied the atmospheres of Saturn and its giant moon Titan.{{Cite web |title=Encounter with saturn |url=https://voyager.jpl.nasa.gov/science/saturn.html |url-status=live |archive-url=https://web.archive.org/web/20130916053405/http://voyager.jpl.nasa.gov/science/saturn.html |archive-date=September 16, 2013 |access-date=August 29, 2013 |publisher=NASA}}

Voyager 1 found that about seven percent of the volume of Saturn's upper atmosphere is helium (compared with 11 percent of Jupiter's atmosphere), while almost all the rest is hydrogen. 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 {{Convert|500|m/s|mph|abbr=unit}}. The wind blows mostly in an easterly direction.

The Voyagers found aurora-like ultraviolet emissions of hydrogen 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 complex hydrocarbon molecules that are carried toward the equator. 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 the rotation of Saturn (the length of a day) at 10 hours, 39 minutes, 24 seconds.

Voyager 1{{'}}s mission included a flyby of Titan, Saturn's largest moon, which had long been known to have an atmosphere. Images taken by Pioneer 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 {{convert|4000|mi|km|order=flip|abbr=on}}, passing behind Titan as seen from Earth and the Sun.

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.{{Cite book |last=Jim Bell |url=https://books.google.com/books?id=KXPoAwAAQBAJ&pg=PT93 |title=The Interstellar Age: Inside the Forty-Year Voyager Mission |year=2015 |publisher=Penguin Publishing Group |isbn=978-0-698-18615-6 |page=93}}

Because observations of Titan were considered vital, the trajectory chosen for Voyager 1 was designed around the optimum Titan flyby, which took it below the south pole of Saturn and out of the plane of the ecliptic, ending its planetary science mission.{{Cite book |last=David W. Swift |url=https://books.google.com/books?id=E-NGFqfq1LsC&pg=PA69 |title=Voyager Tales: Personal Views of the Grand Tour |date=1997 |publisher=AIAA |isbn=978-1-56347-252-7 |page=69}} Had Voyager 1 failed or been unable to observe Titan, Voyager 2's trajectory would have been altered to incorporate the Titan flyby,{{rp|94}} precluding any visit to Uranus and Neptune.{{Cite web |date=February 14, 1990 |title=Voyager – Frequently Asked Questions |url=https://www.jpl.nasa.gov/voyager/frequently-asked-questions/ |url-status=dead |archive-url=https://web.archive.org/web/20211021022802/https://www.jpl.nasa.gov/voyager/frequently-asked-questions |archive-date=October 21, 2021 |access-date=August 4, 2017 |publisher=NASA}} The trajectory Voyager 1 was launched into would not have allowed it to continue on to Uranus and Neptune,{{rp|155}} but could have been altered to avoid a Titan flyby and travel from Saturn to Pluto, arriving in 1986.

{{Clear}}

File:Crescent Saturn as seen from Voyager 1.jpg|alt=View of Saturn lit from the right. Saturn's globe casts its shadow over the rings to the left. Part of the lower hemisphere can be seen through the rings. Some of the spoke-like ring features are visible as bright patches.|Crescent Saturn from 5.3 million km, four days after closest approach

File:Voyager1-saturn-f-ring.jpg|alt=Voyager 1 image of Saturn's F Ring|Voyager 1 image of Saturn's narrow, twisted and braided F Ring.

File:Voyager 1 - view of Saturn's moon Mimas.jpg|alt=Mimas at a range of 425,000 km from Voyager 1|Mimas at a range of 425,000 km. The crater Herschel is at upper right

File:Tethys - PIA01974.jpg|alt=Tethys photographed by Voyager 1 from 1.2 million km|Tethys, with its giant rift valley Ithaca Chasma, from 1.2 million km.

File:Dione from Voyager 1.jpg|alt=Fractured terrain on Dione imaged from a distance of 240,000 km from Voyager 1|Fractured 'wispy terrain' on Dione's trailing hemisphere.

File:Rhea - PIA02270.jpg|alt=Impact craters on the surface of Rhea appear similar to Earth's Moon|The icy surface of Rhea is nearly saturated with impact craters.

File:Titan's thick haze layer-picture from voyager1.jpg|alt=Cream-colored section of a disk is separated from the black space above by a fuzzy blue curve|Titan's thick haze layer is shown in this enhanced Voyager 1 image.

File:Titan Haze.jpg|alt=orange colored area at bottom right is separated from black space at upper left by diagonal series of blue bands|Layers of haze, composed of complex organic compounds, covering Saturn's satellite Titan.

{{center|{{commons-inline|bullet=none|Category:Photos of Saturn system by Voyager 1|the Voyager 1 Saturn encounter}}}}

File:Family portrait (Voyager 1).png of the Solar System acquired by Voyager 1, February 14, 1990]]

File:Voyager 1 - 14 February 1990.png

File:Voyager speed and distance from Sun.svg

File:Pale_Blue_Dot.png image showing Earth from {{convert|6|e9km|e9mi|abbr=off}} appearing as a tiny dot (the bluish-white speck approximately halfway down the light band to the right) within the darkness of deep space.{{Cite news |last=Staff |date=February 12, 2020 |title=Pale Blue Dot Revisited |work=NASA |url=https://photojournal.jpl.nasa.gov/catalog/PIA23645 |url-status=live |access-date=February 12, 2020 |archive-url=https://web.archive.org/web/20200212230826/https://photojournal.jpl.nasa.gov/catalog/PIA23645 |archive-date=February 12, 2020}}]]

On February 14, 1990, Voyager 1 took the first "family portrait" of the Solar System as seen from outside,{{Cite web |title=Photo Caption |url=https://nssdc.gsfc.nasa.gov/photo_gallery/caption/solar_family.txt |url-status=live |archive-url=https://web.archive.org/web/20100908070243/http://nssdc.gsfc.nasa.gov/photo_gallery/caption/solar_family.txt |archive-date=September 8, 2010 |access-date=August 26, 2010 |publisher=Public Information Office}} which includes the image of planet Earth known as Pale 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.

On February 17, 1998, Voyager 1 reached a distance of {{Convert|69|AU|e9mi e9km|abbr=unit}} from the Sun and overtook Pioneer 10 as the most distant spacecraft from Earth.{{Cite news |date=February 17, 1998 |title=Voyager 1 now most distant man-made object in space |publisher=CNN |url=http://edition.cnn.com/TECH/space/9802/17/nasa.distant.objects/ |url-status=dead |access-date=July 1, 2012 |archive-url=https://web.archive.org/web/20120620094059/http://edition.cnn.com/TECH/space/9802/17/nasa.distant.objects/ |archive-date=June 20, 2012}}{{Cite news |last=Clark |first=Stuart |date=September 13, 2013 |title=Voyager 1 leaving solar system matches feats of great human explorers |work=The Guardian |url=https://www.theguardian.com/science/across-the-universe/2013/sep/13/voyager-1-solar-system-great-explorers |url-status=live |access-date=December 18, 2016 |archive-url=https://web.archive.org/web/20190624105328/https://www.theguardian.com/science/across-the-universe/2013/sep/13/voyager-1-solar-system-great-explorers |archive-date=June 24, 2019}} Traveling at about {{convert|17|km/s|mi/s|abbr=unit}}, it has the fastest heliocentric recession speed of any spacecraft.{{cite web |title=Voyager – NASA Probe Sees Solar Wind Decline |url=https://voyager.jpl.nasa.gov/news/details.php?article_id=20 |website=voyager.jpl.nasa.gov |access-date=April 4, 2024 |language=en |archive-date=March 8, 2024 |archive-url=https://web.archive.org/web/20240308102436/https://voyager.jpl.nasa.gov/news/details.php?article_id=20 |url-status=live }}

As Voyager 1 headed for interstellar space, its instruments continued to study the Solar System. Jet Propulsion Laboratory scientists used the plasma wave experiments aboard Voyager 1 and 2 to look for the heliopause, the boundary at which the solar wind transitions into the interstellar medium.{{Cite web |title=Voyager 1 in heliopause |url=https://voyager.jpl.nasa.gov/mission/interstellar.html |url-status=live |archive-url=https://web.archive.org/web/20120514175011/http://voyager.jpl.nasa.gov/mission/interstellar.html |archive-date=May 14, 2012 |access-date=August 18, 2013 |publisher=JPL}} {{as of|2013}}, the probe was moving with a relative velocity to the Sun of about {{convert|38026|mph|km/h|disp=flip|sp=us}}.{{Cite web |title=Mission Status |url=https://voyager.jpl.nasa.gov/mission/status/ |url-status=live |archive-url=https://web.archive.org/web/20180101025244/https://voyager.jpl.nasa.gov/mission/status/ |archive-date=January 1, 2018 |access-date=February 14, 2020 |publisher=JPL}}

With the velocity the probe is currently maintaining, Voyager 1 is traveling about {{convert|325|e6mi|e6km|disp=flip|abbr=unit}} per year,{{Cite news |last=Wall |first=Mike |date=September 12, 2013 |title=It's Official! Voyager 1 Spacecraft Has Left Solar System |work=Space.com |url=https://www.space.com/22729-voyager-1-spacecraft-interstellar-space.html |url-status=live |access-date=May 30, 2014 |archive-url=https://web.archive.org/web/20160118134211/http://m.space.com/22729-voyager-1-spacecraft-interstellar-space.html |archive-date=January 18, 2016}} or about one light-year per 18,000 years.

File:Voyager Path.svgs to both Voyagers]]

Scientists at the Johns Hopkins University Applied Physics Laboratory believe that Voyager 1 entered the termination shock in February 2003.{{Cite news |last=Tobin |first=Kate |date=November 5, 2003 |title=Spacecraft reaches edge of Solar System |publisher=CNN |url=http://edition.cnn.com/2003/TECH/space/11/05/voyager.solar.boundary/ |url-status=live |access-date=August 19, 2013 |archive-url=https://web.archive.org/web/20160304101439/http://edition.cnn.com/2003/TECH/space/11/05/voyager.solar.boundary/ |archive-date=March 4, 2016}} This marks the point where the solar wind slows to subsonic speeds. Some other scientists expressed doubt and discussed this in the journal Nature of November 6, 2003.{{Cite journal |last=Fisk |first=Len A. |date=2003 |title=Planetary Science: Over the edge? |url=https://deepblue.lib.umich.edu/bitstream/2027.42/62712/1/426021a.pdf |journal=Nature |volume=426 |issue=6962 |pages=21–22 |bibcode=2003Natur.426...21F |doi=10.1038/426021a |pmid=14603294 |doi-access=free}} The issue would not be resolved until other data became available, since Voyager 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.{{Cite journal |last1=Krimigis |first1=S.M. |last2=Decker |first2=R.B. |last3=Hill |first3=M.E. |last4=Armstrong |first4=T.P. |last5=Gloeckler |first5=G. |last6=Hamilton |first6=D.C. |last7=Lanzerotti |first7=L.J. |last8=Roelof |first8=E.C. |date=2003 |title=Voyager 1 exited the solar wind at a distance of ~85 au from the Sun |journal=Nature |volume=426 |issue=6962 |pages=45–48 |bibcode=2003Natur.426...45K |doi=10.1038/nature02068 |pmid=14603311 |s2cid=4393867}}{{Cite journal |last1=McDonald |first1=Frank B. |last2=Stone |first2=Edward C. |last3=Cummings |first3=Alan C. |last4=Heikkila |first4=Bryant |last5=Lal |first5=Nand |last6=Webber |first6=William R. |date=2003 |title=Enhancements of energetic particles near the heliospheric termination shock |journal=Nature |volume=426 |issue=6962 |pages=48–51 |bibcode=2003Natur.426...48M |doi=10.1038/nature02066 |pmid=14603312 |s2cid=4387317}}{{Cite journal |last=Burlaga |first=L.F. |date=2003 |title=Search for the heliosheath with Voyager 1 magnetic field measurements |url=https://authors.library.caltech.edu/55625/1/2003-46.pdf |url-status=live |journal=Geophysical Research Letters |volume=30 |issue=20 |pages=n/a |bibcode=2003GeoRL..30.2072B |doi=10.1029/2003GL018291 |archive-url=https://web.archive.org/web/20171202102922/https://authors.library.caltech.edu/55625/1/2003-46.pdf |archive-date=December 2, 2017 |access-date=August 2, 2018 |doi-access=free}}

In May 2005, a NASA press release said that the consensus was that Voyager 1 was then in the heliosheath.{{Cite web |date=May 24, 2005 |title=Voyager Enters Solar System's Final Frontier |url=https://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html |url-status=live |archive-url=https://web.archive.org/web/20190509100336/https://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html |archive-date=May 9, 2019 |access-date=August 7, 2007 |publisher=NASA}} In a scientific session at the American Geophysical Union meeting in New Orleans on May 25, 2005, Ed Stone presented evidence that the craft crossed the termination shock in late 2004.{{Cite web |title=Voyager crosses termination shock |url=https://voyager.jpl.nasa.gov/mission/interstellar.html |url-status=live |archive-url=https://web.archive.org/web/20120514175011/http://voyager.jpl.nasa.gov/mission/interstellar.html |archive-date=May 14, 2012 |access-date=August 29, 2013}} This event is estimated to have occurred on December 15, 2004, at a distance of {{Convert|94|AU|e6mi|abbr=unit}} from the Sun.{{Cite web |date=February 2013 |title=Voyager Timeline |url=https://voyager.jpl.nasa.gov/mission/timeline.html |url-status=live |archive-url=https://web.archive.org/web/20131120031107/http://voyager.jpl.nasa.gov/mission/timeline.html |archive-date=November 20, 2013 |access-date=December 2, 2013 |publisher=NASA/JPL}}

On March 31, 2006, amateur radio operators from AMSAT in Germany tracked and received radio waves from Voyager 1 using the {{convert|20|m|ft|0|adj=on|sp=us}} dish at Bochum with a long integration technique. Retrieved data was checked and verified against data from the Deep Space Network station at Madrid, Spain. This seems to be the first such amateur tracking of Voyager 1.{{cite web |title=Voyager 1 received by AMSAT-DL group – Official Website of AMSAT-SM Sweden |url=https://www.amsat.se/2006/04/02/voyager-1-received-by-amsat-dl-group/ |website=amsat.se |access-date=April 5, 2024 |archive-date=April 5, 2024 |archive-url=https://web.archive.org/web/20240405101446/https://www.amsat.se/2006/04/02/voyager-1-received-by-amsat-dl-group/ |url-status=live }}

It was confirmed on December 13, 2010, that Voyager 1 had passed the reach of the radial outward flow of the solar 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.{{Cite web |date=December 13, 2010 |title=Voyager 1 Sees Solar Wind Decline |url=http://solarsystem.nasa.gov/news/display.cfm?News_ID=36121 |url-status=dead |archive-url=https://web.archive.org/web/20110614073203/http://solarsystem.nasa.gov/news/display.cfm?News_ID=36121 |archive-date=June 14, 2011 |access-date=September 16, 2013 |publisher=NASA}}{{Cite journal |last1=Krimigis |first1=S.M. |last2=Roelof |first2=E.C. |last3=Decker |first3=R.B. |last4=Hill |first4=M.E. |year=2011 |title=Zero outward flow velocity for plasma in a heliosheath transition layer |journal=Nature |volume=474 |issue=7351 |pages=359–361 |bibcode=2011Natur.474..359K |doi=10.1038/nature10115 |pmid=21677754 |s2cid=4345662}} On this date, the spacecraft was approximately {{Convert|116|AU|e9km e9mi|abbr=unit}} from the Sun.{{Cite news |last=Amos |first=Jonathan |date=December 14, 2010 |title=Voyager near Solar System's edge |work=BBC News |url=https://www.bbc.co.uk/news/science-environment-11988466 |url-status=live |access-date=December 21, 2010 |archive-url=https://web.archive.org/web/20211122034204/https://www.bbc.co.uk/news/science-environment-11988466 |archive-date=November 22, 2021}}

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 the Family Portrait photograph of the planets was taken in 1990. After the first roll the spacecraft had no problem in reorienting itself with Alpha 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 as Voyager 1.{{Cite web |last=NASA |title=Voyager – The Interstellar Mission |url=https://voyager.jpl.nasa.gov/news/answer_wind.html |url-status=live |archive-url=https://web.archive.org/web/20130927125706/http://voyager.jpl.nasa.gov/news/answer_wind.html |archive-date=September 27, 2013 |access-date=September 16, 2013 |publisher=NASA}}{{Cite news |date=March 9, 2011 |title=Voyager: Still dancing 17 billion km from Earth |work=BBC News |url=https://www.bbc.co.uk/news/science-environment-12688246 |url-status=live |access-date=June 20, 2018 |archive-url=https://web.archive.org/web/20180928220350/https://www.bbc.co.uk/news/science-environment-12688246 |archive-date=September 28, 2018}}

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 constellation Ophiuchus as observed from the Earth on May 21, 2011.

On December 1, 2011, it was announced that Voyager 1 had detected the first Lyman-alpha radiation originating from the Milky 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.{{Cite magazine |date=December 1, 2011 |title=Voyager Probes Detect 'invisible' Milky Way Glow |url=https://www.nationalgeographic.com/science/article/111201-voyager-probes-milky-way-light-hydrogen-sun-nasa-space |archive-url=https://web.archive.org/web/20210421164043/https://www.nationalgeographic.com/science/article/111201-voyager-probes-milky-way-light-hydrogen-sun-nasa-space |url-status=dead |archive-date=April 21, 2021 |magazine=National Geographic |access-date=December 4, 2011}}

NASA announced on December 5, 2011, that Voyager 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.{{Cite news |date=December 6, 2011 |title=Spacecraft enters 'cosmic purgatory' |work=CNN |url=http://lightyears.blogs.cnn.com/2011/12/06/spacecraft-enters-cosmic-purgatory/ |url-status=dead |access-date=December 7, 2011 |archive-url=https://web.archive.org/web/20190607115011/http://lightyears.blogs.cnn.com/2011/12/06/spacecraft-enters-cosmic-purgatory/ |archive-date=June 7, 2019}}

NASA announced in June 2012 that the probe was detecting changes in the environment that were suspected to correlate with arrival at the heliopause.{{Cite web |date=June 18, 2012 |title=NASA Voyager 1 Spacecraft Nears Interstellar Space |url=https://www.space.com/16167-voyager1-spacecraft-interstellar-space.html |url-status=live |archive-url=https://web.archive.org/web/20130705080432/http://www.space.com/16167-voyager1-spacecraft-interstellar-space.html |archive-date=July 5, 2013 |access-date=August 19, 2013 |publisher=Space.com}} 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 the heliosphere from the Sun. The craft thus began to enter the interstellar medium at the edge of the Solar System.{{Cite web |date=June 14, 2012 |title=Data From NASA's Voyager 1 Point to Interstellar Future |url=https://www.nasa.gov/mission_pages/voyager/voyager20120614.html |url-status=live |archive-url=https://web.archive.org/web/20120617040828/http://www.nasa.gov/mission_pages/voyager/voyager20120614.html |archive-date=June 17, 2012 |access-date=June 16, 2012 |publisher=NASA}}

Voyager 1 became the first spacecraft to cross the heliopause in August 2012, then at a distance of {{Convert|121|AU|mi km|abbr=unit}} from the Sun, although this was not confirmed for another year.{{Cite web |last1=Cook |first1=J.-R.C. |last2=Agle |first2=D.C. |last3=Brown |first3=D. |date=September 12, 2013 |title=NASA Spacecraft Embarks on Historic Journey into Interstellar Space |url=https://www.nasa.gov/mission_pages/voyager/voyager20130912.html |url-status=live |archive-url=https://web.archive.org/web/20200413080742/http://www.nasa.gov/mission_pages/voyager/voyager20130912.html |archive-date=April 13, 2020 |access-date=September 14, 2013 |website=NASA}}

As of September 2012, sunlight took 16.89 hours to get to Voyager 1 which was at a distance of 121 AU. The apparent magnitude of the Sun from the spacecraft was −16.3 (about 30 times brighter than the full Moon).{{Cite web |last=Peat |first=Chris |date=September 9, 2012 |title=Spacecraft escaping the Solar System |url=https://www.heavens-above.com/SolarEscape.aspx |url-status=live |archive-url=https://web.archive.org/web/20180511013456/http://www.heavens-above.com/SolarEscape.aspx |archive-date=May 11, 2018 |access-date=March 16, 2014 |publisher=Heavens-Above}} The spacecraft was traveling at {{Convert|17.043|km/s|mi/s|abbr=on}} relative to the Sun. At this rate, it would need about 17,565 years to travel a single light-year. To compare, Proxima Centauri, the closest star to the Sun, is about 4.2 light-years ({{val|2.65|e=5|u=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 constellation Ophiuchus.

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 be cosmic rays emanating from supernova 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.{{Cite web |last=Wolchover |first=Natalie |date=October 9, 2012 |title=Did NASA's Voyager 1 Spacecraft Just Exit the Solar System? |url=https://www.livescience.com/23822-voyager-spacecraft-solar-system.html |url-status=live |archive-url=https://web.archive.org/web/20131003054345/http://www.livescience.com/23822-voyager-spacecraft-solar-system.html |archive-date=October 3, 2013 |access-date=August 20, 2013 |publisher=livescience}}

Ed Roelof, space scientist at Johns Hopkins University and principal investigator for the Low-Energy Charged Particle instrument on the spacecraft, declared that "most scientists involved with Voyager 1 would agree that [these two criteria] have been sufficiently satisfied". However, the last criterion for officially declaring that Voyager 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), 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 the California 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."{{Cite magazine |last=Matson |first=John |date=December 4, 2012 |title=Despite Tantalizing Hints, Voyager 1 Has Not Crossed into the Interstellar Medium |url=https://blogs.scientificamerican.com/observations/2012/12/04/despite-tantalizing-hints-voyager-1-has-not-crossed-into-the-interstellar-medium/ |magazine=Scientific American |access-date=August 20, 2013 |archive-date=March 13, 2013 |archive-url=https://web.archive.org/web/20130313051418/http://blogs.scientificamerican.com/observations/2012/12/04/despite-tantalizing-hints-voyager-1-has-not-crossed-into-the-interstellar-medium/? |url-status=live }} The magnetic field in this region was 10 times more intense than Voyager 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.{{Cite web |date=December 3, 2012 |title=Voyager 1 Can 'Taste' the Interstellar Shore |url=http://news.discovery.com/space/voyager-1-flys-into-a-mystery-magnetic-highway-121203.html |url-status=dead |archive-url=https://web.archive.org/web/20121205081342/http://news.discovery.com/space/voyager-1-flys-into-a-mystery-magnetic-highway-121203.html |archive-date=December 5, 2012 |access-date=September 16, 2013 |website=Discovery News |publisher=Discovery Channel}}{{Cite web |last=Oakes |first=Kelly |date=December 3, 2012 |title=Voyager 1 is still not out of the Solar System |url=https://blogs.scientificamerican.com/basic-space/2012/12/03/voyager-1-is-still-not-out-of-the-solar-system/ |url-status=live |archive-url=https://web.archive.org/web/20130310144859/http://blogs.scientificamerican.com/basic-space/2012/12/03/voyager-1-is-still-not-out-of-the-solar-system/ |archive-date=March 10, 2013 |access-date=September 16, 2013 |website=Basic Space Blog |publisher=Scientific American}}{{Cite news |date=December 4, 2012 |title=Voyager 1 probe leaving Solar System reaches 'magnetic highway' exit |work=Daily News & Analysis |agency=Reuters |url=http://www.dnaindia.com/scitech/report_voyager-1-probe-leaving-solar-system-reaches-magnetic-highway-exit12-4-2012-8-04-28-am_1773168%7C |url-status=live |access-date=December 4, 2012 |archive-url=https://web.archive.org/web/20230813133221/https://www.dnaindia.com/technology/report_voyager-1-probe-leaving-solar-system-reaches-magnetic-highway-exit12-4-2012-8-04-28-am_1773168%7C |archive-date=August 13, 2023}}

In March 2013, it was announced that Voyager 1 might have become the first spacecraft to enter interstellar 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.{{Cite web |date=March 20, 2013 |title=Voyager 1 has entered a new region of space, sudden changes in cosmic rays indicate |url=http://www.agu.org/news/press/pr_archives/2013/2013-11.shtml |url-status=dead |archive-url=https://web.archive.org/web/20130322025117/http://www.agu.org/news/press/pr_archives/2013/2013-11.shtml |archive-date=March 22, 2013 |publisher=American Geophysical Union}}{{Cite web |last=Cook |first=J.-R |date=September 12, 2013 |title=How Do We Know When Voyager Reaches Interstellar Space? |url=https://www.jpl.nasa.gov/news/news.php?release=2013-278 |url-status=live |archive-url=https://web.archive.org/web/20190322195142/https://www.jpl.nasa.gov/news/news.php?release=2013-278 |archive-date=March 22, 2019 |access-date=September 15, 2013 |publisher=NASA / Jet Propulsion Lab}}

In 2013 Voyager 1 was exiting the Solar System at a speed of about {{Convert|3.6|AU|e6mi e6km|abbr=unit}} per year, which is 61,602 km/h, 4.83 times the diameter of Earth (12,742 km) per hour; whereas Voyager 2 is going slower, leaving the Solar System at {{Convert|3.3|AU|e6mi e6km|abbr=unit}} per year.{{Cite web |title=Voyager – Fast Facts |url=https://voyager.jpl.nasa.gov/mission/fastfacts.html |url-status=live |archive-url=https://web.archive.org/web/20111008174443/http://voyager.jpl.nasa.gov/mission/fastfacts.html |archive-date=October 8, 2011 |access-date=August 2, 2018 |website=voyager.jpl.nasa.gov}} Each year, Voyager 1 increases its lead over Voyager 2.

Voyager 1 reached a distance of {{Convert|135|AU|e9mi e9km|abbr=unit}} from the Sun on May 18, 2016. On September 5, 2017, that had increased to about {{Convert|139.64|AU|e9mi e9km|abbr=unit}} from the Sun, or just over 19 light-hours; at that time, Voyager 2 was {{Convert|115.32|AU|e9mi e9km|abbr=unit}} from the Sun.

Its progress can be monitored at NASA's website.See § External links.

File:Cosmic Rays at Voyager 1.png|Plot showing a dramatic increase in the rate of cosmic ray particle detection by the Voyager 1 spacecraft, October 2011 to October 2012

File:Solar wind at Voyager 1.png|Plot showing a dramatic decrease in the rate of solar wind particle detection by Voyager 1, October 2011 to October 2012

File:Interstellar probes (cropped).jpg.]]

File:Voyager Captures Sounds of Interstellar Space.webm from interstellar space]]

On September 12, 2013, NASA officially confirmed that Voyager 1 had reached the interstellar 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.{{Cite journal |last=Cowen |first=R. |year=2013 |title=Voyager 1 has reached interstellar space |journal=Nature |doi=10.1038/nature.2013.13735 |s2cid=123728719 |doi-access=free}}{{Cite journal |last=Kerr |first=R. A. |year=2013 |title=It's Official – Voyager Has Left the Solar System |journal=Science |volume=341 |issue=6151 |pages=1158–1159 |bibcode=2013Sci...341.1158K |doi=10.1126/science.341.6151.1158 |pmid=24030991}}{{Cite journal |last1=Gurnett |first1=D.A. |last2=Kurth |first2=W.S. |last3=Burlaga |first3=L.F. |last4=Ness |first4=N.F. |year=2013 |title=In Situ Observations of Interstellar Plasma with Voyager 1 |journal=Science |volume=341 |issue=6153 |pages=1489–1492 |bibcode=2013Sci...341.1489G |doi=10.1126/science.1241681 |pmid=24030496 |s2cid=206550402 }} By this point, most space scientists had abandoned the hypothesis that a change in magnetic field direction must accompany a crossing of the heliopause; a new model of the heliopause predicted that no such change would be found.{{Cite journal |last1=Swisdak |first1=M. |last2=Drake |first2=J.F. |last3=Opher |first3=M. |year=2013 |title=A Porous, Layered Heliopause |journal=The Astrophysical Journal |volume=774 |issue=1 |page=L8 |arxiv=1307.0850 |bibcode=2013ApJ...774L...8S |doi=10.1088/2041-8205/774/1/L8 |s2cid=118459113}}

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 of plasma oscillations observed beginning on April 9, 2013, triggered by a solar outburst that had occurred in March 2012 (electron density is expected to be two orders of magnitude higher outside the heliopause than within).

Weaker sets of oscillations measured in October and November 2012{{Cite news |last=Morin |first=Monte |date=September 12, 2013 |title=NASA confirms Voyager 1 has left the Solar System |work=Los Angeles Times |url=http://www.latimes.com/science/sciencenow/la-sci-sn-nasa-confirms-voyager-1-has-exited-the-solar-system-20130912,0,3406650.story |url-status=live |access-date=September 12, 2013 |archive-url=https://web.archive.org/web/20130913013722/http://www.latimes.com/science/sciencenow/la-sci-sn-nasa-confirms-voyager-1-has-exited-the-solar-system-20130912,0,3406650.story |archive-date=September 13, 2013}} provided additional data. An indirect measurement was required because Voyager 1's plasma spectrometer had stopped working in 1980. In September 2013, NASA released recordings of audio transductions of these plasma waves, the first to be measured in interstellar space.{{Cite web |title=Voyage 1 Records "Sounds" of Interstellar Space |url=https://www.space.com/22777-voyager-1-records-sounds-from-interstellar-space-video.html |url-status=live |archive-url=https://web.archive.org/web/20131227211216/http://www.space.com/22777-voyager-1-records-sounds-from-interstellar-space-video.html |archive-date=December 27, 2013 |access-date=December 20, 2013 |publisher=Space.com}}

While Voyager 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 the aphelion of Sedna, and it has not yet entered the Oort cloud, the source region of long-period comets, regarded by astronomers as the outermost zone of the Solar System.{{Cite web |last=Ghose |first=Tia |date=September 13, 2013 |title=Voyager 1 Really Is in Interstellar Space: How NASA Knows |url=https://www.space.com/22797-voyager-1-interstellar-space-nasa-proof.html |url-status=live |archive-url=https://web.archive.org/web/20130915213629/http://www.space.com/22797-voyager-1-interstellar-space-nasa-proof.html |archive-date=September 15, 2013 |access-date=September 14, 2013 |website=Space.com |publisher=TechMedia Network}}

In October 2020, astronomers reported a significant unexpected increase in density in the space beyond the Solar System as detected by the Voyager 1 and Voyager 2 space probes. According to the researchers, this implies that "the density gradient is a large-scale feature of the VLISM (very local interstellar medium) in the general direction of the heliospheric nose".{{Cite news |last=Starr |first=Michelle |date=October 19, 2020 |title=Voyager Spacecraft Detect an Increase in The Density of Space Outside The Solar System |work=ScienceAlert |url=https://www.sciencealert.com/for-some-reason-the-density-of-space-is-higher-just-outside-the-solar-system |url-status=live |access-date=October 19, 2020 |archive-url=https://web.archive.org/web/20201019133221/https://www.sciencealert.com/for-some-reason-the-density-of-space-is-higher-just-outside-the-solar-system |archive-date=October 19, 2020}}{{Cite journal |last1=Kurth |first1=W.S. |last2=Gurnett |first2=D.A. |date=August 25, 2020 |title=Observations of a Radial Density Gradient in the Very Local Interstellar Medium by Voyager 2 |journal=The Astrophysical Journal Letters |volume=900 |pages=L1 |bibcode=2020ApJ...900L...1K |doi=10.3847/2041-8213/abae58 |s2cid=225312823 |doi-access=free |number=1}}

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.{{Cite news |last1=Hatfield |first1=Miles |last2=Cofield |first2=Calla |date=May 11, 2021 |title=As NASA's Voyager 1 Surveys Interstellar Space, Its Density Measurements Are Making Waves |work=NASA |url=https://www.jpl.nasa.gov/news/as-nasas-voyager-1-surveys-interstellar-space-its-density-measurements-are-making-waves |url-status=live |access-date=May 11, 2021 |archive-url=https://web.archive.org/web/20210511183247/https://www.jpl.nasa.gov/news/as-nasas-voyager-1-surveys-interstellar-space-its-density-measurements-are-making-waves |archive-date=May 11, 2021}}

In May 2022, NASA reported that Voyager 1 had begun transmitting "mysterious" and "peculiar" telemetric data to the Deep 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.{{Cite web |last=Kooser |first=Amanda |title=NASA's Voyager 1 Space Probe From the '70s Troubled by Mysterious Glitch |url=https://www.cnet.com/science/space/nasas-voyager-1-space-probe-from-the-70s-troubled-by-mysterious-glitch/ |url-status=live |archive-url=https://web.archive.org/web/20220523190122/https://www.cnet.com/science/space/nasas-voyager-1-space-probe-from-the-70s-troubled-by-mysterious-glitch/ |archive-date=May 23, 2022 |access-date=May 24, 2022 |website=CNET |language=en}}{{Cite web |title=Humanity's most distant spacecraft is sending back weird signals from beyond our solar system |url=https://www.msn.com/en-us/news/technology/humanitys-most-distant-spacecraft-is-sending-back-weird-signals-from-beyond-our-solar-system/ar-AAXDut6 |url-status=live |archive-url=https://web.archive.org/web/20220523235958/http://www.msn.com/en-us/news/technology/humanitys-most-distant-spacecraft-is-sending-back-weird-signals-from-beyond-our-solar-system/ar-AAXDut6 |archive-date=May 23, 2022 |access-date=May 24, 2022 |website=MSN |language=en-US}}

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.{{Cite news |last=Tariq Malik |date=August 30, 2022 |title=NASA solves Voyager 1 data glitch mystery, but finds another |language=en |work=Space.com |url=https://www.space.com/voyager-1-data-glitch-solved |url-status=live |access-date=September 1, 2022 |archive-url=https://web.archive.org/web/20220831232300/https://www.space.com/voyager-1-data-glitch-solved |archive-date=August 31, 2022}}{{Cite web |last=Greicius |first=Tony |date=August 30, 2022 |title=Engineers Solve Data Glitch on NASA's Voyager 1 |url=https://www.nasa.gov/feature/jpl/engineers-solve-data-glitch-on-nasa-s-voyager-1 |url-status=live |archive-url=https://web.archive.org/web/20220831053515/https://www.nasa.gov/feature/jpl/engineers-solve-data-glitch-on-nasa-s-voyager-1/ |archive-date=August 31, 2022 |access-date=September 1, 2022 |website=NASA}}

Voyager 1 began transmitting unreadable data on November 14, 2023. On December 12, 2023, NASA announced that Voyager 1{{'s}} flight data system was unable to use its telemetry modulation unit, preventing it from transmitting scientific data.{{Cite web |last=Paul |first=Andrew |date=December 14, 2023 |title=Voyager 1 is sending back bad data, but NASA is on it |url=https://www.popsci.com/science/voyager-computer-issue/ |access-date=December 15, 2023 |website=Popular Science |language=en-US |archive-date=December 22, 2023 |archive-url=https://web.archive.org/web/20231222034606/https://www.popsci.com/science/voyager-computer-issue/ |url-status=live }} On March 24, 2024, NASA announced that they had made significant progress on interpreting the data being received from the spacecraft.{{Cite web |date=March 13, 2024 |title=NASA Engineers Make Progress Toward Understanding Voyager 1 Issue – The Sun Spot |url=https://blogs.nasa.gov/sunspot/2024/03/13/nasa-engineers-make-progress-toward-understanding-voyager-1-issue/ |access-date=April 28, 2024 |website=blogs.nasa.gov |language=en-US |archive-date=May 1, 2024 |archive-url=https://web.archive.org/web/20240501122208/https://blogs.nasa.gov/sunspot/2024/03/13/nasa-engineers-make-progress-toward-understanding-voyager-1-issue/ |url-status=live }} 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.{{Cite web |first1=Monisha |last1=Ravisetti |date=February 6, 2024 |title=NASA's interstellar Voyager 1 spacecraft isn't doing so well – here's what we know |url=https://www.space.com/nasa-voyager-spacecraft-mission-deep-space-update |access-date=March 1, 2024 |publisher=space.com |archive-date=March 1, 2024 |archive-url=https://web.archive.org/web/20240301232621/https://www.space.com/nasa-voyager-spacecraft-mission-deep-space-update |url-status=live }}

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.{{Cite web |author1=Stephen Clark |date=February 15, 2024 |title=Humanity's most distant space probe jeopardized by computer glitch |url=https://arstechnica.com/space/2024/02/humanitys-most-distant-space-probe-jeopardized-by-computer-glitch/ |access-date=March 1, 2024 |publisher=ARS Technica |archive-date=March 1, 2024 |archive-url=https://web.archive.org/web/20240301232622/https://arstechnica.com/space/2024/02/humanitys-most-distant-space-probe-jeopardized-by-computer-glitch/ |url-status=live }} The Voyager team began developing a workaround,{{cite web |url=https://arstechnica.com/space/2024/04/the-diagnosis-is-in-bad-memory-knocked-nasas-aging-voyager-1-offline/ |title=NASA knows what knocked Voyager 1 offline, but it will take a while to fix |first=Stephen |last=Clark |publisher=Ars Technica |date=April 6, 2024 |access-date=April 6, 2024 |archive-date=April 6, 2024 |archive-url=https://web.archive.org/web/20240406130959/https://arstechnica.com/space/2024/04/the-diagnosis-is-in-bad-memory-knocked-nasas-aging-voyager-1-offline/ |url-status=live }}{{Cite web |date=April 4, 2024 |title=Engineers Pinpoint Cause of Voyager 1 Issue, Are Working on Solution – Voyager |url=https://blogs.nasa.gov/voyager/2024/04/04/engineers-pinpoint-cause-of-voyager-1-issue-are-working-on-solution/ |access-date=April 13, 2024 |website=blogs.nasa.gov |language=en-US |archive-date=April 12, 2024 |archive-url=https://web.archive.org/web/20240412203857/https://blogs.nasa.gov/voyager/2024/04/04/engineers-pinpoint-cause-of-voyager-1-issue-are-working-on-solution/ |url-status=live }} 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.{{Cite news |last=Strickland |first=Ashley |date=April 22, 2024 |title=Voyager 1 is sending data back to Earth for the first time in 5 months |url=https://www.cnn.com/2024/04/22/world/voyager-1-communication-issue-cause-fix-scn/index.html |access-date=April 24, 2024 |language=en |website=CNN |archive-date=April 24, 2024 |archive-url=https://web.archive.org/web/20240424020430/https://www.cnn.com/2024/04/22/world/voyager-1-communication-issue-cause-fix-scn/index.html |url-status=live }}

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 69.63 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.{{cite web |last1=Rak |first1=Gwendolyn |title=How NASA is Hacking Voyager 1 Back to Life |url=https://spectrum.ieee.org/voyager-1 |website=IEEE Spectrum |access-date=9 May 2024 |language=en}} On May 22, NASA announced that Voyager 1 "resumed returning science data from two of its four instruments", with work towards the others ongoing.{{cite web | url=https://blogs.nasa.gov/voyager/2024/05/22/voyager-1-resumes-sending-science-data-from-two-instruments/ | title=Voyager 1 Resumes Sending Science Data from Two Instruments – Voyager | date=May 22, 2024 }} On June 13, NASA confirmed that the probe returns data from all four instruments.{{Cite web|url=https://www.jpl.nasa.gov/news/voyager-1-returning-science-data-from-all-four-instruments|title=Voyager 1 Returning Science Data From All Four Instruments|website=NASA Jet Propulsion Laboratory (JPL)}}

In October 2024, the probe turned off its X-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 the S-band transmitter, that was previously used in 1981.{{cite web |last=Greicius |first=Tony |url=https://blogs.nasa.gov/voyager/2024/10/ |title=After Pause, NASA's Voyager 1 Communicating With Mission Team |publisher=NASA |date=October 28, 2024 |access-date=October 31, 2024 }} NASA reported that the team reactivated the X-band transmitter and then resumed collecting data in mid-November.{{cite web |title=NASA's Voyager 1 Resumes Regular Operations After Communications Pause |publisher=NASA |url=https://blogs.nasa.gov/voyager/2024/11/26/nasas-voyager-1-resumes-regular-operations-after-communications-pause/ |date=26 November 2024}} {{PD notice}}

File:Voyager 1 Radio Signal 21 Feb 2013.jpg

In December 2017, NASA successfully fired all four of Voyager 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 allowed Voyager 1 to continue transmitting data to NASA for two to three more years.{{Cite news |date=December 4, 2017 |title=Voyager 1 spacecraft thrusters fire up after decades idle |newspaper=The Irish Times |url=https://www.irishtimes.com/news/science/voyager-1-spacecraft-thrusters-fire-up-after-decades-idle-1.3315654 |url-status=live |access-date=December 4, 2017 |archive-url=https://web.archive.org/web/20190428121442/https://www.irishtimes.com/news/science/voyager-1-spacecraft-thrusters-fire-up-after-decades-idle-1.3315654 |archive-date=April 28, 2019}}

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.{{Cite web |title=Voyager – Frequently Asked Questions |url=https://voyager.jpl.nasa.gov/frequently-asked-questions/ |url-status=live |archive-url=https://web.archive.org/web/20230813133216/https://voyager.jpl.nasa.gov/frequently-asked-questions/ |archive-date=August 13, 2023 |access-date=June 26, 2020 |website=voyager.jpl.nasa.gov |language=en}}

Some thrusters 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 their hydrazine 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 with Ars Technica.{{Cite web |last=Clark |first=Stephen |date=October 24, 2023 |title=NASA wants the Voyagers to age gracefully, so it's time for a software patch |url=https://arstechnica.com/space/2023/10/nasa-wants-the-voyagers-to-age-gracefully-so-its-time-for-a-software-patch/ |access-date=October 27, 2023 |website=Ars Technica |archive-date=October 27, 2023 |archive-url=https://web.archive.org/web/20231027215228/https://arstechnica.com/space/2023/10/nasa-wants-the-voyagers-to-age-gracefully-so-its-time-for-a-software-patch/ |url-status=live }} 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 on Voyager 2, which is less distant from Earth, before deploying it on Voyager 1.

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.{{cite web |last1=Rabie |first1=Passant |title=NASA Pulls Off Delicate Thruster Swap, Keeping Voyager 1 Mission Alive |url=https://gizmodo.com/nasa-pulls-off-delicate-thruster-swap-keeping-voyager-1-mission-alive-2000497434 |website=Gizmodo |access-date=26 September 2024 |date=11 September 2024}}

File:VoyagerOne Aug 2 2018.png|A simulated view of Voyager 1 relative to the Solar System on August 2, 2018.

File:Voyagerprobes Aug 2 2018.png|A simulated view of the Voyager probes relative to the Solar System and heliopause on August 2, 2018.

File:NearSunStarsSimple.jpg|In about 50,000 years Voyager 1 will be as distant as several nearby stars

Provided Voyager 1 does not collide with anything and is not retrieved, the New 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, whereas New Horizons received only a single such boost, from its Jupiter flyby in 2007. {{As of|2018}}, New Horizons is traveling at about {{Convert|14|km/s|mi/s|abbr=unit}}, {{Convert|3|km/s|mi/s|abbr=unit}} slower than Voyager 1, and New Horizons, being closer to the sun, is slowing more rapidly.{{Cite web |date=August 17, 2006 |title=New Horizons Salutes Voyager |url=http://pluto.jhuapl.edu/news_center/news/081706.php |url-status=dead |archive-url=https://web.archive.org/web/20141113224847/http://pluto.jhuapl.edu/news_center/news/081706.php |archive-date=November 13, 2014 |access-date=November 3, 2009 |publisher=New Horizons}}

Voyager 1 is expected to reach the theorized Oort cloud in about 300 years{{Cite web |title=Catalog Page for PIA17046 |url=https://photojournal.jpl.nasa.gov/catalog/PIA17046 |url-status=live |archive-url=https://web.archive.org/web/20200612114300/https://photojournal.jpl.nasa.gov/catalog/PIA17046 |archive-date=June 12, 2020 |access-date=April 27, 2014 |website=Photo Journal |publisher=NASA}}{{Cite web |date=September 12, 2013 |title=It's Official: Voyager 1 Is Now In Interstellar Space |url=https://www.universetoday.com/104717/its-official-voyager-1-is-now-in-interstellar-space/ |url-status=live |archive-url=https://web.archive.org/web/20191230182842/https://www.universetoday.com/104717/its-official-voyager-1-is-now-in-interstellar-space/ |archive-date=December 30, 2019 |access-date=April 27, 2014 |website=UniverseToday}} and take about 30,000 years to pass through it. Though it is not heading towards any particular star, in about 40,000 years, it will pass within {{Convert|1.6|ly|pc|lk=on|abbr=off}} of the star Gliese 445, which is at present in the constellation Camelopardalis and 17.1 light-years from Earth. That star is generally moving towards the Solar System at about {{convert|119|km/s|km/h mph|abbr=on}}.{{Cite web |date=August 9, 2010 |title=Voyager – Mission – Interstellar Mission |url=https://voyager.jpl.nasa.gov/mission/interstellar.html |url-status=live |archive-url=https://web.archive.org/web/20120514175011/http://voyager.jpl.nasa.gov/mission/interstellar.html |archive-date=May 14, 2012 |access-date=March 17, 2011 |publisher=NASA}} NASA says that "The Voyagers are destined{{snd}}perhaps eternally{{snd}}to wander the Milky Way."{{Cite web |title=Future |url=https://voyager.jpl.nasa.gov/mission/interstellar.html |url-status=live |archive-url=https://web.archive.org/web/20120514175011/http://voyager.jpl.nasa.gov/mission/interstellar.html |archive-date=May 14, 2012 |access-date=October 13, 2013 |publisher=NASA}} In 300,000 years, it will pass within less than 1 light-year of the M3V star TYC 3135–52–1.{{Cite journal |last1=Bailer-Jones |first1=Coryn A.L. |last2=Farnocchia |first2=Davide |date=April 3, 2019 |title=Future stellar flybys of the Voyager and Pioneer spacecraft |journal=Research Notes of the AAS |volume=3 |issue=4 |page=59 |arxiv=1912.03503 |bibcode=2019RNAAS...3...59B |doi=10.3847/2515-5172/ab158e |s2cid=134524048 |doi-access=free}}

{{Main|Voyager Golden Record}}

File:The Sounds of Earth - GPN-2000-001976.jpg

File:Voyager Golden Record greeting in English.ogg) in English recorded on the Voyager Golden Record]]

Both Voyager space probes carry a gold-plated audio-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.{{Cite magazine |last=Ferris |first=Timothy |date=May 2012 |title=Timothy Ferris on Voyagers' Never-Ending Journey |url=https://www.smithsonianmag.com/science-nature/Timothy-Ferris-on-Voyagers-Never-Ending-Journey.html |url-status=dead |archive-url=https://web.archive.org/web/20131104221550/http://www.smithsonianmag.com/science-nature/Timothy-Ferris-on-Voyagers-Never-Ending-Journey.html |archive-date=November 4, 2013 |access-date=August 19, 2013 |magazine=Smithsonian Magazine}}{{Cite web |last1=Gambino |first1=Megan |title=What Is on Voyager's Golden Record? |url=https://www.smithsonianmag.com/science-nature/what-is-on-voyagers-golden-record-73063839/ |access-date=January 15, 2024 |website=Smithsonian Magazine |language=en |archive-date=April 8, 2020 |archive-url=https://web.archive.org/web/20200408014620/https://www.smithsonianmag.com/science-nature/what-is-on-voyagers-golden-record-73063839/ |url-status=live }} The record, made under the direction of a team including Carl Sagan and Timothy Ferris, includes photos of the Earth and its lifeforms, a range of scientific information, spoken greetings from people such as the Secretary-General of the United Nations (Kurt Waldheim) and the President of the United States (Jimmy Carter) and a medley, "Sounds of Earth".{{Cite web |title=Voyager Golden record |url=https://voyager.jpl.nasa.gov/spacecraft/goldenrec.html |url-status=live |archive-url=https://web.archive.org/web/20110927062632/http://voyager.jpl.nasa.gov/spacecraft/goldenrec.html/ |archive-date=September 27, 2011 |access-date=August 18, 2013 |publisher=JPL}}

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 by Wolfgang Amadeus Mozart, Blind Willie Johnson, Chuck Berry and Valya 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.{{Cite web |title=Voyager Golden record |url=https://voyager.jpl.nasa.gov/spacecraft/goldenrec.html |url-status=live |archive-url=https://web.archive.org/web/20110927062632/http://voyager.jpl.nasa.gov/spacecraft/goldenrec.html/ |archive-date=September 27, 2011 |access-date=August 18, 2013 |publisher=JPL}} 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.{{Clear}}

{{cmn|colwidth=45em|

• The Farthest, a 2017 documentary on the Voyager program
• Interstellar probe
• List of artificial objects leaving the Solar System
• List of missions to the outer planets
• Local Interstellar Cloud
• Space exploration
• Specific orbital energy of Voyager 1
• Timeline of artificial satellites and space probes

}}

{{Reflist|30em}}

{{Commons category}}

• [https://science.nasa.gov/mission/voyager/ NASA Voyager website]
• [https://web.archive.org/web/20150215231024/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Voyager_1 Voyager 1 Mission Profile] by [https://solarsystem.nasa.gov/ NASA's Solar System Exploration]
• Where is Voyager? – Powered by NASA's Eyes [https://eyes.nasa.gov/apps/solar-system/#/sc_voyager_1 Eyes on the Solar System – NASA/JPL]
• [https://live-counter.com/where-is-voyager-1/ Position of Voyager 1 (Live-Counter)]
• [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1977-084A Voyager 1 (NSSDC Master Catalog)]
• [https://www.heavens-above.com/SolarEscape.aspx Heavens-above.com: Spacecraft Escaping the Solar System] – current positions and diagrams
• [https://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf JPL Voyager Telecom Manual]
• [https://www.universetoday.com/81662/voyager-1-has-outdistanced-the-solar-wind/ Voyager 1 Has Outdistanced the Solar Wind]
• {{Cite web |last=Gray |first=Meghan |title=Voyager and Interstellar Space |url=http://www.deepskyvideos.com/videos/other/voyager.html |website=Deep Space Videos |publisher=Brady Haran}}

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Category:1977 in spaceflight

Category:1977 in the United States

Category:1977 robots

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Category:Missions to Jupiter

Category:Missions to Saturn

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Category:September 1977 in the United States

Category:Spacecraft escaping the Solar System

Category:Spacecraft launched by Titan rockets

Category:Spacecraft launched in 1977

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