Voyager 1 and Its Journey Toward The Interstellar Universe
Launched on September 5, 1977, just two weeks after Voyager 2, Voyager 1 now holds the title of the farthest spacecraft from Earth. According to NASA’s Jet Propulsion Laboratory, it travels at approximately 17 kilometers per second. Importantly, Voyager 1 and its twin, Voyager 2, have become the first and only spacecraft to travel into interstellar space, venturing beyond our solar system. Voyager 1 and 2 entered interstellar space in 2012 and 2018, respectively.
NASA’s Jet Propulsion Laboratory (JPL) has stated that Voyager 1 will have enough fuel and resources to continue its mission until at least 2025. Despite being 46 years old, Voyager 1 still holds the record for being the “most distant human-made object” from Earth, at more than 24 billion kilometers, or roughly 15 billion miles away, while its twin moves slightly slower, about 20 billion kilometers (13 billion miles) from Earth. As a result, its radio signals take approximately 22.5 hours to reach Earth.
With a velocity of over 15 kilometers per second, the Voyager spacecraft will still take a considerable amount of time to approach another star. The primary goal of the Voyagers was to explore the outer planets of the Solar system: Jupiter, Saturn, Uranus, and Neptune. Voyager 1 specifically focused on the close-up investigation of Jupiter and Saturn. Originally planned as a five-year mission, they have surpassed expectations and become the longest-operating spacecraft in history.
NASA foresaw that these spacecraft would eventually step into interstellar space; therefore, they produced two golden records which comprise various different sounds from whale calls to greetings in 55 languages. They placed the records inside Voyagers, searching for traces of extraterrestrials, or what’s called an “alien,” and trying out different ways of communication in case of an encounter. Additionally, these disks include illustrations of how to use the records and a map of the universe that indicates the sun’s position among nearby neutron stars so that extraterrestrials would be conscious of where the spacecraft came from. Both spacecraft utilize 3 radioisotope thermoelectric generators which are capable of converting the heat from plutonium’s radioactive decay into electricity.
The Problem: An Unreliable Messenger
The Voyager spacecraft has exceeded expectations over its 46-year journey, venturing far beyond its initial mission parameters. However, in November, NASA announced that Voyager 1 had begun transmitting gibberish—unreadable, repeating patterns of code—back to Earth due to a computer fault. This rendered the data it transmitted since November unusable. However, unlike its sibling, Voyager 2’s communication systems remain operational.
On April 20th, Voyager finally communicated with NASA, providing updates on the health and status of its engineering systems by transmitting useful, coherent, and understandable information. According to the NASA team, the data received indicates that Voyager 1’s operating system is functioning properly. NASA promptly identified the underlying cause: 3% of the flight data system’s memory is corrupted due to the breakdown of a single chip responsible for memory restoration and some software code. The reason behind the chip’s malfunction remains unknown, but it has affected Voyager 1’s data transmission.
Considering repairing or replacing the chip is not feasible, the team decided to store the code from the chip elsewhere in the system’s memory remotely. Since they could not find a single location to host all of the code, they divided the code into sections and stored them in various spots within the system. Along the way, they adjusted the storage regions, preparing them for the addition of the affected code. Later on, after necessary changes were made, they sent the code to its new storage in the flight data subsystem (FDS) memory.
On April 18th, after a total of 45 hours of travel across space, Voyager 1 successfully transmitted its signal. Then, on April 20th, the response signal returned, indicating that the code modification had worked, and Voyager 1 was once again able to deliver readable and useful engineering data. On the same day, Voyager communicated with NASA, providing updates on the health and operating status of its engineering systems and finally sending “useful” and “understandable” information. The team will continue working on adapting the software, aiming to “enable the spacecraft to begin returning science data again.”
As Voyager Project Manager Suzanne Dodd remarked, “We never know for sure what’s going to happen with the Voyagers, but it constantly amazes me when they just keep going.”
In conclusion, Voyager 1 has provided scientists and engineers insights not only about our solar system but also about the interstellar area, leading to important scientific discoveries, which include observations of Jupiter’s rings, active volcanism on Io, and the identification of 23 new moons belonging to outer planets. Therefore, resolving Voyager 1’s technical issue is crucial for the continuation of advancements in humanity’s understanding of the universe.
