Throughout the years, humanity has embarked on an incredible journey into space, launching a wide array of objects. Many of these have remained in orbit around the Earth or eventually returned to our atmosphere, where they either burned up or sometimes made their way back to the surface.
However, if we truly want to send something deep into space, it requires significant effort—specifically, rocket-fueled propulsion. The spacecraft that venture out towards the farthest parts of our solar system require an initial boost to escape Earth’s gravitational pull and then further assistance from the gravity of the planets they encounter. Thanks to the minimal friction in space paired with the vastness of the universe, these spacecraft keep moving forward. The furthest human-made object from Earth, and the one likely to keep that title, is the Voyager 1 spacecraft, with Voyager 2 trailing behind.
Voyager 1 was launched just a few weeks after its sibling, Voyager 2, in 1977. It earned its name because it was on a faster route to Jupiter, making it the first Voyager to reach that planet. Today, Voyager 1 is more than 15 billion miles away from our home planet, while Voyager 2 hovers at over 12 billion miles.
This year marks 47 years of operation for both probes, making them NASA’s longest-running spacecraft. Both Voyager missions have passed by Jupiter and Saturn, and Voyager 2 has made additional flybys of Uranus and Neptune.
According to NASA, these are the only two spacecraft that have “directly sampled interstellar space.” Interstellar space is the region that exists beyond the heliosphere, the protective bubble formed by solar wind. This bubble diminishes where the solar wind’s force meets interstellar wind. Voyager 1 and 2 have successfully exited the heliosphere and are now in interstellar space, although they are technically still considered part of the solar system for the time being, until they cross the boundary of the Oort Cloud. Voyager 1 is expected to reach the outer edge of this cloud in about 300 years.
NASA engineers continue to send commands to Voyager 1 and receive valuable data in return. Given the immense distance, it takes over 22 and a half hours for light to travel from Earth to the spacecraft, and the same amount of time for signals from Voyager 1 to reach back. This means engineers have to wait two days to confirm if a command has been successful.
In May 2024, Voyager 1 resumed transmitting scientific data from two of its four instruments after a computer malfunction sidelined them in November 2023. By June 2024, all four instruments were up and running again, thanks to troubleshooting efforts by NASA. According to NASA, these four instruments study “plasma waves, magnetic fields, and particles.”
Voyager 1 is also known for capturing one of the most famous images in space exploration history. In 1990, while still a relatively close 3.7 billion miles away, it took a photograph that became known as the “pale blue dot.”
In this stunning image, Earth appears as a tiny dot in the vastness of space, suspended in a ray of sunlight. The photograph was created from a series of 60 images taken as Voyager passed beyond Neptune. Project managers directed the probe to look back at its home planet and capture this final series of shots. According to NASA, Voyager 1 is one of only three spacecraft capable of taking such an image (with Voyager 2 and New Horizons being the others). The Solar System Family Portrait also included Neptune, Uranus, Saturn, Jupiter, and Venus.
The images that formed this iconic photo were captured just half an hour before Voyager’s cameras were permanently switched off in February 1990. All file data were successfully transmitted back to Earth and processed by May of that same year.
Both Voyager 1 and Voyager 2 continue their journeys through space, gradually losing power and capabilities until they can no longer communicate. Depending on their power reserves, scientific data may still be sent back to Earth for several more years even after the instruments are shut down.