NASA / JPL-CaltechWhile Pioneer 10 and 11 are now inactive, New Horizons and both Voyager spacecrafts remain operational, powered by radioisotope thermoelectric generators. Since the coronavirus pandemic in mid-March, NASA has had no contact with Voyager 2, but an upgraded deep space network dish made a successful call on October 29.
At distances of 148 and 125 Astronomical Units, respectively, both Voyager 1 and 2 have passed the ... menopause and have successfully entered interplanetary space. This means that increased power and signal strength are needed to communicate over greater distances.
As of 2020, the plutonium-238 onboard is producing just 69% of the initial heat energy, and that translates into only about ~50% of the original output power. The key is through NASA’s Deep Space Network : a collection of radio antennae designed to communicate with humanity’s most distant spacecraft.
Crews conduct critical upgrades and repairs to the 70-meter-wide (230-foot-wide) radio antenna Deep ... Space Station 43 in Canberra, Australia. CSIROThere are three major radio antenna facilities around the world: one in Canberra, Australia, one in Madrid, Spain, and one in Gold stone, California.
NASA / Jet Propulsion Lathe trip to Neptune still, even to this day, represents the only close encounter humanity has ever had with our Solar System’s eighth and final (for now) planet, as well as with Triton, the largest known object to originate in our Kuiper belt. The discoveries from that flyby were spectacular, as a number of fantastic features were discovered: Neptune’s ring system, a number of small, inner moons, and a series of features on Triton, including cryovolcanism and varied terrain similar to what we’d discover some 26 years later when New Horizons flew past Pluto.
Over the past 31 years, it’s continued to follow that trajectory, rendering it invisible to every member of the Deep Space Network except for the one dish in Australia. This image of NASA's Deep Space Station 43 (DSS43) radio telescope belies its massive size.
At 70 ... meters in diameter, it's the only transmitter in the Southern Hemisphere that's large enough and powerful enough to send commands to Voyager 2. Fortunately, the decision was made to upgrade all of these, which should enable NASA to do what no other facility can do: send commands to Voyager 2.
Voyager 2 can only be sent commands from one telescope now: NASA's Deep Space Network's sole member in the Southern Hemisphere. Image: Phoenix7777/Wikimedia Commons; Data: HORIZONS System, GPL, NASA On October 29, 2021, enough of the upgrades had been executed that mission operators for Voyager 2 decided to perform a critical test: to send a series of commands to Voyager 2 for the first time since the upgrades began.
Although it takes about 36 light-hours for a signal to travel round-trip from Earth to Voyager 2, NASA announced on November 2 that the test was successful. Voyager 2 returned a signal that confirmed the call was received, followed by a successful execution of the commands.
Both worlds ... are covered in a mix of nitrogen, carbon dioxide, and water-based ices, but Triton is larger and has a significantly higher density. The upgraded infrastructure will play a critical role in any upcoming Moon-to-Mars exploration efforts, will support any crewed missions such as Artemis, will provide communication and navigation infrastructure, and will also assist with communications to NASA’s Mars Perseverance rover, scheduled to land on Mars on February 18, 2021.
It was expanded to 70 meters (230 feet) 15 years later, but none of the subsequent repairs or upgrades compare to the work being done today. As long as these spacecraft remain operational in some capacity, simply continuing to upgrade our facilities here on Earth will enable us to gather data for years, and likely even decades, to come.
Voyager 1 and 2 are already the most distant operational spacecraft ever launched from Earth, and continue to set new records. They’ve both passed the menopause and entered interstellar space, probing different celestial hemispheres as they go.
Each new piece of data they send back is a first: the first time we’ve directly sampled space outside our Solar System from so far away. I guess as healthy as we are at the table right now,” Suzanne Dodd, the Voyager project manager at NASA's Jet Propulsion Laboratory (GPL) said, drawing a big laugh from the audience at the Spaciest VI conference in Pasadena, California, on May 11.
The unmanned Voyager 1 and 2 probes were launched in 1977 on a mission to visit all the outer planets of the solar system. (Image credit: Karl Tate, SPACE.com)Dodd was actually the youngster on the Voyager reunion panel.
She was joined by Voyager Project Scientist Ed Stone and retired Voyager Mission Design Manager Charley Koalas, who were both on the project when it was in the planning stages in the early 1970s. When the Voyagers were launched in 1977, NASA expected them to last four or five years, long enough to get them through close encounters with Jupiter and Saturn.
Voyager 1, which flew out of the plane of the solar system after its 1980 flyby of Saturn, is in interstellar space at 127 AU's. Stone and Koalas recalled their astonishment when an image showing two exploding volcanoes on Jupiter's moon Io came into GPL late on a Friday afternoon in March 1979.
The plumes went hundreds of miles above the surface, and the fallout covered an area the size of France. “It was an incredible time when every day there were so many things we were discovering that we just moved on to the next one,” Stone added.
(Image credit: NASA/Carla Coffin)The Voyager missions also forever changed the way spacecraft were built and operated. “The key thing about Voyager that was a revolution was it was a totally computer-controlled spacecraft that flies itself and has fault protection on board so that if something goes wrong, it takes action,” he said.
He used computers to determine which ones would allow the spacecraft to make the best approaches to Jupiter, Saturn and their moons. GPL uses the powerful antennas of the Deep Space Network to communicate with the distant spacecraft.
“Looking forward, we expect to get 10 more years of scientific data out of the Voyager spacecraft,” Dodd said. Engineers are already in discussions with the Deep Space Network about what experiments could be conducted with those signals before the spacecraft fall silent.
As of February 5, Voyager 2 remains stable, has resumed taking science data and it's continuing to be evaluated, the agency said. One overall struggle for both Voyager spacecraft is maintaining power, which is needed for the science instruments and the heaters that keep them from freezing in deep space.
That boundary is the outermost edge of the Oort Cloud, a group of small objects influenced by the gravity of our sun. They will be able to take unprecedented observations in this part of interstellar space and send them back to mission scientists.
The scientists can still communicate with Voyager 2, even in interstellar space, but the data takes about 16.5 hours to travel back to Earth. The spacecraft was expected to make a scheduled maneuver and rotate360 degrees to help calibrate its magnetometer, or magnetic field instrument.
But data from Voyager 2 showed a delay in this maneuver, which also left two systems running on high power at the same time. That triggered the spacecraft's fault protection software routine, which responds if it senses that Voyager 2 is consuming too much energy.
On Tuesday, engineers were able to shut down one of the systems using a large amount of power and turn the science instruments back on, according to NASA. Mission operators report that Voyager 2 continues to be stable and that communications between Earth and the spacecraft are good.
At NASA's Jet Propulsion Laboratory in Pasadena, California, engineers are still communicating with the spacecraft and receiving telemetry. On Saturday, Jan. 25, Voyager 2 didn't execute a scheduled maneuver in which the spacecraft rotates 360 degrees in order to calibrate its onboard magnetic field instrument.
Analysis of the telemetry from the spacecraft indicated that an unexplained delay in the onboard execution of the maneuver commands inadvertently left two systems that consume relatively high levels of power operating at the same time. The team is now reviewing the status of the rest of the spacecraft and working on returning it to normal operations.
Due to the natural decay of the material inside the RTG, Voyager 2's power budget goes down by about 4 watts per year. If, for example, the spacecraft fuel lines were to freeze and break, Voyager would no longer be able to point its antenna back at Earth to send data and receive commands.
The temperature of the spacecraft is maintained either through the use of heaters or by taking advantage of excess heat from other onboard instruments and systems. As a result, mission engineers have to wait about 34 hours to find out if their commands have had the desired effect on the spacecraft.
Launched in 1977, Voyagers 1 and 2 are the longest-running spacecraft, still operating at more than 11 billion miles from home, decades after the end of their nominal goal of exploring the outer solar system planets. The craft has five functioning instruments remaining, which it still uses to collect data and send back to Earth on its long journey into deep space.
After all these years The Voyager spacecraft launched in 1977 as twin spacecraft, each with ten instruments to explore space and tour the solar system, sending back humanity’s first close-up look at most of the outer planets. But since 1989, both have been exploring the empty space beyond the planets, and returning priceless information about how far the solar atmosphere extends its influence.
Most of them have been switched off intentionally, as the imaging cameras, for instance, are not useful so far from any sunlight or photographical objects. But they are still measuring cosmic rays, magnetic fields and other charged particles that fill interstellar space far beyond the worldly realm of the planets.
By measuring these particles, astronomers are learning just how far the Sun’s energy extends, and how those fields interact with the interstellar medium beyond the solar system’s edges. In 2017, engineers turned on Voyager 1’s older thrusters, ones that hadn’t been used in 37 years.
They have pushed the instruments to new limits, and are proving that these pioneers, aged as they are, can still reveal powerful information about the cosmos.