The Epic Journey of Voyager 1

In August 2012, Voyager 1 became the first spacecraft to cross into interstellar space, passing through the heliosphere, a sudden increase in cosmic rays and a forty-fold sudden increase in plasma density.

Voyager 1 is a space probe launched by NASA on September 5th, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin Voyager 2, Voyager 1 has been operating for 45 years, 3 months and 7 days as of December 13, 2022. It communicates through NASA's Deep Space Network to receive routine commands and to transmit data to Earth. At a distance of 158.79 AU from Earth as of November 7, 2022, Voyager 1 is the most distant human-made object from Earth.

Each Voyager space probe carries a gold-plated audio-visual disc, should the spacecraft ever be found by intelligent life forms from other planetary systems. The disc carries 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 and the President of the United States and a medley, Sounds of Earth, that includes the sounds of whales, a baby crying, waves breaking on a shore, and a collection of music including works by Wolfgang Amadeus Mozart, Blind Willie Johnson, Chuck Berry and Valya Balkanska. Other Eastern and Western classics are included, as well as various performances of indigenous music from around the world. The record also contains greetings in 55 different languages.

The probe made flybys of Jupiter, Saturn, and Saturn's largest moon, Titan. NASA had a choice of either doing a Pluto or Titan flyby; exploration of the moon took priority because it was known to have a substantial atmosphere. 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.

On February 14, 1990, an image of planet Earth dubbed the Pale Blue Dot was taken, by the Voyager 1 space probe from a record distance of about 40.5 AU, as part of that day's Family Portrait series of images of the Solar System.

In the photograph, Earth's apparent size is less than a pixel, the planet appears as a tiny dot against the vastness of space, among bands of sunlight reflected by the camera.

Voyager 1, which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and take one last photograph of Earth across a great expanse of space, at the request of astronomer and author Carl Sagan. The phrase Pale Blue Dot was coined by Sagan in his reflections on the photograph's significance, documented in his 1994 book of the same name.

As part of the Voyager program and like its sister craft Voyager 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 the heliopause and entered interstellar space on August 25th, 2012, making it the first spacecraft to do so. Two years later, Voyager 1 began experiencing a third tsunami wave of coronal mass ejections from the Sun that continued to at least December 15th, 2014, further confirming that the probe is indeed in interstellar space.

In a further testament to the robustness of Voyager 1, the Voyager team tested the spacecraft's trajectory correction manoeuvre thrusters in late 2017 (the first time these thrusters had been fired since 1980), a project enabling the mission to be extended by two to three years. Voyager 1's extended mission is expected to continue until about 2025, when its radioisotope thermoelectric generators will no longer supply enough electric power to operate its scientific instruments.