40 years old and still going strong

Overview

Launched in 1977 from Cape Canaveral, Voyager 1 was designed to fly past Jupiter, Saturn, and Titan. After completing its primary mission in 1980, the probe was re-purposed to study the Outer Solar System. Since then, it has become the first craft to cross into interstellar space. Voyager 1 has vastly increased what we know about the Solar System; after 38 years, the probe continues to send back valuable data about space far from the Sun. Truly, Voyager 1 has gone where no spacecraft has gone before.

Mission Details

Originally designed as part of the Mariner program, Voyager 1 was separated from that probe family due to budget cuts. Designed by JPL, the craft was equipped with 11 scientific instruments, of which 5 are currently active. These 5 active instruments are the spectrometer (UVS), magnetometer (MAG), charged particle detector (LECP), cosmic ray detector (CRS), and the plasma wave system (PWS). The other 6 instruments, including the camera, are either disabled or defective. Several subsystems form the craft’s computer, including the Computer Command Subsystem (CCS) and the Attitude and Articulation Control Subsystem (AACS). The craft transmits data using its high-gain dish antenna, which operates at 2.3 or 8.4 GHz. Signals are received using the Deep Space Network, which broadcasts commands at 2.1 GHz. Powering the craft is an array of radioisotope thermoelectric generators, or RTGs. These power sources use the natural decay of plutonium to power the craft. However, due to the nature of radioactive decay, the generator cannot provide as much power today (420 watts) as it could at launch (470 watts). As a result, scientific instruments have to be turned off to ensure that the computer receives enough power. Voyager 1’s RTGs are expected to last until 2025, at which point they will no longer be able to power any of the craft’s instruments. Despite this flaw, RTGs are well suited for use in the Outer Solar System, where there is not enough sunlight to use solar power. At launch, the craft massed 722 kg.

Voyager 1 launched atop a Titan III-Centaur with an added 4th stage. The craft arrived at Jupiter during the January of 1979, with a closest approach of 349 km from the center of the gas giant. At Jupiter, the probe analyzed radiation belts and magnetic fields. Notably, Voyager 1’s photographs led to the discovery of volcanic activity on Io, one of Jupiter’s moons. After obtaining a gravity assist from the massive planet, the probe continued towards Saturn. Arriving near the end of 1980, Voyager 1 flew as close as 124 km above Saturn’s clouds, analyzing the planet’s atmosphere and rings. The probe also found auroras at varying latitudes across the gas planet. As part of the Saturn flyby, Voyager 1 encountered Titan, Saturn’s largest moon. It used telemetry systems light measurement to determine the composition of the moon’s atmosphere, and Titan’s mass was calculated through its effect on the craft’s trajectory. If the Titan encounter was not possible for some reason, the probe’s trajectory could have been altered to include a flyby of Pluto; however, this was not necessary. Having completed its primary mission, the probe continued on its trajectory into the Outer Solar System, boosted by a gravity assist from Saturn. Voyager 1 officially passed Pioneer 10 in 1998, becoming the farthest spacecraft from the Sun. In August of 2012, the probe officially crossed the heliopause, though this was not confirmed by NASA until September of next year. As of January 2016, Voyager 1 is the only spacecraft to officially enter interstellar space.

Historical Significance

The pale blue dot is Earth

Voyager 1’s missions have had a huge impact on our knowledge of the Solar System. Through the probe, we have learned valuable information about Jupiter and Saturn. We discovered volcanic activity on Io and analyzed the atmosphere of Titan. Using Voyager 1, we’ve also been able to take amazing photographs, including the famous “Pale Blue Dot” photo of Earth from afar.

We’ve also gathered mountains of information about the edge of the Solar System. Voyager 1 is the only craft able to measure cosmic rays and solar wind at the boundary between the Sun and the rest of the Milky Way. We’ve learned about the heliosphere, the bubble of solar radiation which marks the beginning of the interstellar medium. The forerunner of such missions as Cassini and Galileo, Voyager 1 represents our furthest venture into the science of space.

Conclusion

The amount of data we’ve obtained through Voyager 1 is second to none.

Rating: ★★★★★