The breakdown in communication began in mid-March when NASA announced that Deep Space Station 43 (DSS-43) in Canberra, Australia—the only antenna on the planet that can send commands to Voyager 2—needed critical upgrades. One of its two radio transmitters had not been upgraded in nearly fifty years.
DSS-43 was slated to be shut down for nearly a year, but enough of the upgrades were completed for communication with the craft to start again. The work on the antenna is still underway and will likely be finished in February.
Suzanne Dodd, the director of Jet Propulsion Laboratory’s Interplanetary Network Directorate and project manager for the Voyager Interstellar Mission, told The National Interest that she was satisfied with the work on the antenna and knew that sending commands to Voyager 2—currently about twelve billion miles away from Earth—would begin again relatively quickly.
“The work on the antenna upgrades went smoothly, especially considering travel to Australia was very restricted,” she said. “We were not able to send the engineers from JPL that we normally would have to participate in the work. But the team in Australia did a great job in keeping the work on schedule and consulting with JPL engineers remotely.”
Voyager 1 and Voyager 2 launched a few weeks apart in 1977 and were given the monumental task of performing an unprecedented “grand tour” of the solar system’s giant planets. Voyager 1 managed to fly by Jupiter and Saturn, and Voyager 2 followed suit and then zipped past Uranus and Neptune as well.
In August 2012, Voyager 1 made its historic entry into interstellar space, a first for a man-made object. Then Voyager 2 did the same on November 5, 2018—amazing to think that these two probes, launched four decades ago, are still technically within our solar system.
And they won’t be leaving anytime soon, as the boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, an assortment of objects that are still under the influence of the sun’s gravity. It will likely take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly past it.
Voyager 2’s achievement in reaching interstellar space was confirmed by comparing data from different instruments—namely, the cosmic ray subsystem, the low-energy charged particle instrument, and the magnetometer—aboard the spacecraft. Mission scientists have determined that the probe crossed the outer edge of the heliosphere, the protective bubble of particles and magnetic fields created by our sun. This particular boundary, which is called the heliopause, is where the hot solar wind meets the cold and dense interstellar void.
For Chris Laws, teaching professor of astronomy at University of Washington, he believes that “since the region of interstellar space around the sun is not especially well understood, any direct data we can get is immensely valuable.”
“I also think it’s important from a somewhat more emotional, existential point of view,” he told TNI. “Voyagers 1 and 2 really introduced us to the outer solar system, and they represent the parts of us that have traveled farthest from home—it’s good to hear from your students, and to know that they’re doing well.”
The Voyager probes are powered by using heat from the decay of radioactive material, which is contained in a device called a radioisotope thermal generator. The power output falls by about four watts per year, which means that they will run out of power supply likely within this decade.
“The Voyager spacecraft were designed very robustly, with the goal of getting all the way to Neptune for Voyager 2. Obviously, it has lasted another thirty-one years since then, traveling through the heliopause and now since November 2018 through interstellar space. Its longevity is a testament to the excellent spacecraft design and the hard work of dedicated engineers who have stayed with the mission for the last three decades,” Dodd told TNI.
“It’s anticipated the Voyager spacecraft will continue operations for another five-plus years, assuming that no anomalies occur. We are turning off science instrument heaters and science instruments yearly in order to reduce the power consumption as the power output gets less each year.”
When that dreaded day eventually arrives, Dodd said that it will be “very difficult to say goodbye to Voyager.”
“It’s had such a long and exciting mission,” she added. “It will be missed by the team members, but also by all the folks in the general public who follow the mission.”
Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn. Image: Reuters