Voyager 1

4 Articles

Voyager 1’s Primary Thrusters Revived Before DSN Command Pause

May 15, 2025 by 43 Comments

As with all aging bodies, clogged tubes form an increasing issue. So too with the 47-year old Voyager 1 spacecraft and its hydrazine thrusters. Over the decades silicon dioxide from an aging rubber diaphragm in the fuel tank has been depositing on the inside of fuel tubes. By switching between primary, backup and trajectory thrusters the Voyager team has been managing this issue and kept the spacecraft oriented towards Earth. Now this team has performed another amazing feat by reviving the primary thrusters that had been deemed a loss since a heater failure back in 2004.

Unlike the backup thrusters, the trajectory thrusters do not provide roll control, so reviving the primary thrusters would buy the mission a precious Plan B if the backup thrusters were to fail. Back in 2004 engineers had determined that the heater failure was likely unfixable, but over twenty years later the team was willing to give it another shot. Analyzing the original failure data indicated that a glitch in the heater control circuit was likely to blame, so they might actually still work fine.

To test this theory, the team remotely jiggled the heater controls, enabled the primary thrusters and waited for the spacecraft’s star tracker to drift off course so that the thrusters would be engaged by the onboard computer. Making this extra exciting was scheduled maintenance on the Deep Space Network coming up in a matter of weeks, which would have made troubleshooting impossible for months.

To their relief the changes appears to have worked, with the heaters clearly working again, as are the primary thrusters. With this fix in place, it seems that Voyager 1 will be with us for a while longer, even as we face the inevitable end to the amazing Voyager program.

The Long Goodbye: More Instruments Shut Down On The Voyagers As End Nears

March 7, 2025 by 50 Comments

Saying farewell is hard, and in the case of the Voyager 1 & 2 spacecraft doubly so, seeing as how they have been with us for more than 47 years. From the highs of the 1970s and 1980s during their primary mission in our Solar System, to their journey into the unknown of Deep Space, every bit of information which their instruments record and send back is something unique that we could not obtain any other way. Yet with the shutting down of two more instruments, both spacecraft are now getting awfully close to the end of their extended missions.

Last February 25 the cosmic ray system (CRS) on Voyager 1 was disabled, with the Low Energy Charged Particle Instrument (LECP) on Voyager 2 to follow on March 24. With each spacecraft losing about 4 watts of available power per year from their RTGs, the next few instruments to be turned off are already known. Voyager 1’s LECP will be turned off next year, with that same year Voyager 2’s CRS also getting disabled.

This would leave both spacecraft with only their magnetometer (MAG) and plasma wave subsystem (PWS). These provide data on the local magnetic field and electron density, respectively, with at least one of these instruments on each spacecraft likely to remain active until the end of this decade, possibly into the next. With some luck both spacecraft will see their 50th birthday before humanity’s only presence in Deep Space falls silent.

Thanks to [Mark Stevens] for the tip.

Amateur Radio Operators Detect Signals From Voyager 1

December 11, 2024 by 41 Comments

At the time of its construction in the 1950s, the Dwingeloo Radio Observatory was the largest rotatable telescope in the world with a dish diameter of 25 meters. It was quickly overtaken in the rankings but was used by astronomers for decades until it slowly fell into disuse in the early 2000s. After a restoration project the telescope is now a national heritage site in the Netherlands where it is also available for use by radio amateurs. Recently this group was able to receive signals from Voyager 1.

Famously, Voyager 1 is the furthest manmade object from Earth, having been launched on a trajectory out of the solar system in 1977. As a result of distance and age, the signals it sends out are incredibly faint. The team first had to mount a new antenna to the dish, which was not originally designed for signals in this frequency which added to the challenge. They then needed to use orbital predictions of the spacecraft in order to target the telescope and also make the correct adjustments to the received signal given that there is significant Doppler shift now as well. But with that all out of the way, the team was successfully able to receive the Voyager 1 signal on this telescope.

Only a few telescopes in the world have ever been able to accomplish this feat, making it all the more impressive. Normally Voyager 1 is received using the Deep Space Network, a fleet of much larger dishes stationed around the world and designed for these frequencies. But this team is used to taking on unique challenges. They also decoded the first ham radio station on the moon and made a radar image of the moon using LoRa.

Dwingeloo telescope receives signals from Voyager 1

Voyager 1 Fault Forces Switch To S-Band

October 31, 2024 by 70 Comments

We hate to admit it, but whenever we see an article about either Voyager spacecraft, our thoughts immediately turn to worst-case scenarios. One of these days, we’ll be forced to write obituaries for the plucky interstellar travelers, but today is not that day, even with news of yet another issue aboard Voyager 1 that threatens its ability to communicate with Earth.

According to NASA, the current problem began on October 16 when controllers sent a command to turn on one of the spacecraft’s heaters. Voyager 1, nearly a light-day distant from Earth, failed to respond as expected 46 hours later. After some searching, controllers picked up the spacecraft’s X-band downlink signal but at a much lower power than expected. This indicated that the spacecraft had gone into fault protection mode, likely in response to the command to turn on the heater. A day later, Voyager 1 stopped communicating altogether, suggesting that further fault protection trips disabled the powerful X-band transmitter and switched to the lower-powered S-band downlink.

This was potentially mission-ending; the S-band downlink had last been used in 1981 when the probe was still well within the confines of the solar system, and the fear was that the Deep Space Network would not be able to find the weak signal. But find it they did, and on October 22 they sent a command to confirm S-band communications. At this point, controllers can still receive engineering data and command the craft, but it remains to be seen what can be done to restore full communications. They haven’t tried to turn the X-band transmitter back on yet, wisely preferring to further evaluate what caused the fault protection error that kicked this whole thing off before committing to a step like that.

Following Voyager news these days feels a little morbid, like a death watch on an aging celebrity. Here’s hoping that this story turns out to have a happy ending and that we can push the inevitable off for another few years. While we wait, if you want to know a little more about the Voyager comms system, we’ve got a deep dive that should get you going.

Thanks to [Mark Stevens] for the tip.