Voyager 1
First spacecraft to enter interstellar space, launched in 1977.
Voyager 1, a NASA space probe launched on September 5, 1977, was built to explore the outer Solar System and the interstellar region beyond the Sun’s heliosphere. Its twin, Voyager 2, had launched 16 days earlier. The probe communicates with Earth via the NASA Deep Space Network, which sends commands and receives data. Real-time distance and velocity information comes from NASA and JPL. At 171.19 AU from Earth, it holds the record as the farthest human-made object. It is expected to reach a distance of one light-day from Earth by November 2026.
The probe flew past Jupiter, Saturn, and Saturn’s largest moon, Titan. NASA chose the Titan flyby over a Pluto encounter because Titan was known to have a thick atmosphere. Voyager 1 examined the weather, magnetic fields, and rings of both gas giants and was the first to send back detailed images of their moons.
As part of the Voyager program, the spacecraft’s extended mission involves locating and studying the outer heliosphere’s boundaries and regions, as well as beginning exploration of interstellar space. On August 25, 2012, Voyager 1 crossed the heliopause and became the first spacecraft to enter interstellar space. Two years later, it experienced a third wave of coronal mass ejections from the Sun, which continued until at least December 15, 2014, confirming its interstellar location.
In 2017, the Voyager team fired the spacecraft’s trajectory correction maneuver thrusters for the first time since 1980, extending the mission by two to three years. Successful thruster revivals followed in 2018, 2019, and 2025. The extended mission is expected to keep returning scientific data for several more years. Its radioisotope thermoelectric generators may provide enough power for engineering data until 2036. As of 2026, only two instruments remain operational: the Plasma Wave Subsystem and the magnetometer.
The mission’s origins trace back to a 1960s proposal for a Grand Tour of the outer planets, which led NASA to begin work in the early 1970s. Voyager 1 was initially planned as Mariner 11 under the Mariner program. Budget cuts reduced the mission to a Jupiter and Saturn flyby, and it was renamed the Mariner Jupiter-Saturn probes. The name changed to Voyager when the probe designs diverged significantly from earlier Mariner missions.
Voyager 1 was built by the Jet Propulsion Laboratory. Its bus is a decagonal prism.
Quick Facts
- Mission Type
- Outer planetary, heliosphere, and interstellar medium exploration
- Operator
- NASA/Jet Propulsion Laboratory
- Cospar Id
- 1977-084A
- Satcat
- 10321
- Spacecraft Type
- Mariner Jupiter-Saturn
- Manufacturer
- Jet Propulsion Laboratory
- Dry Mass
- 721.9 kg
- Launch Mass
- 815 kg
- Power
- 470 watts (at launch)
- Launch Rocket
- Titan IIIE
- Launch Site
- Cape Canaveral Launch Complex 41
Facts from the source article.
Lore & Background
Voyager 1 was built by the Jet Propulsion Laboratory (JPL) and launched from Cape Canaveral Air Force Station aboard a Titan IIIE launch vehicle. Its launch almost failed because the Titan's LR-91 second stage shut down prematurely, leaving 1200 lb of propellant unburned, but the Centaur stage compensated. The probe made flybys of Jupiter, Saturn, and Saturn's largest moon, Titan, with the Titan flyby prioritized over a Pluto flyby because Titan was known to have a substantial atmosphere. It studied the weather, magnetic fields, and rings of the two gas giants and was the first probe to provide detailed images of their moons.
The spacecraft has a 3.7 m diameter high-gain Cassegrain antenna for communication via the Deep Space Network, transmitting data on Deep Space Network Channel 18 at 2.3 GHz or 8.4 GHz, while signals from Earth are sent at 2.1 GHz. It carries three radioisotope thermoelectric generators (RTGs) that generated about 470 W at launch, with power declining over time due to the 87.7-year half-life of plutonium-238 and thermocouple degradation. As of 2026, only two instruments remain operational: the Plasma Wave Subsystem and magnetometer. The probe's extended mission is to locate and study the regions and boundaries of the outer heliosphere and begin exploring the interstellar medium.
Reader's Guide
Voyager 1's significance lies in its unprecedented journey beyond the Solar System. As the first human-made object to cross the heliopause and enter interstellar space on August 25, 2012, it provided direct measurements of the interstellar medium. Its extended mission continues to return scientific data, with the RTGs expected to supply enough power for engineering data until 2036. The probe's legacy includes detailed studies of Jupiter and Saturn, their moons, rings, and magnetic fields, as well as the first close-up images of Titan. The Voyager team's successful firing of trajectory correction maneuver thrusters in 2017, after decades of inactivity, extended the mission by two to three years, with further thruster revivals in 2018, 2019, and 2025. Voyager 1 is projected to reach a distance of one light day from Earth in November 2026, cementing its role as a pioneer in deep-space exploration.
Did You Know?
- Voyager 1 was launched 16 days after its twin, Voyager 2, but reached Jupiter and Saturn sooner.
- It crossed the heliopause and entered interstellar space on August 25, 2012, the first spacecraft to do so.
- The probe's RTGs may supply enough electric power to return engineering data until 2036.
- As of 2026, only two instruments are operational: the Plasma Wave Subsystem and magnetometer.
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