Voyager 1 Fault Forces Switch To S-Band

October 31, 2024 by Dan Maloney 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.

Voyager Command Glitch Causes Unplanned Pause In Communications

July 29, 2023 by Dan Maloney 31 Comments

Important safety tip: When you’re sending commands to the second-most-distant space probe ever launched, make really, really sure that what you send isn’t going to cause any problems.

According to NASA, that’s just what happened to Voyager 2 last week, when uplinked commands unexpectedly shifted the 46-year-old spacecraft’s orientation by just a couple of degrees. Of course, at a distance of nearly 20 billion kilometers, even fractions of a degree can make a huge difference, especially since the spacecraft’s high-gain antenna (HGA) is set up for very narrow beamwidths; 2.3° on the S-band channel, and a razor-thin 0.5° on the X-band side. That means that communications between the spacecraft and the Canberra Deep Space Communication Complex — the only station capable of talking to Voyager 2 now that it has dipped so far below the plane of the ecliptic — are on pause until the spacecraft is reoriented.

Luckily, NASA considered this as a possibility and built safety routines into Voyager‘s program that will hopefully get it back on track. The program uses the onboard star tracker to get a fix on the bright star Canopus, and from there figures out which way the spacecraft needs to move to get pointed back at Earth. The contingency program runs automatically several times a year, just in case something like this happens.

That’s the good news; the bad news is that the program won’t run again until October 15. While that’s really not that far away, mission controllers will no doubt find it an agonizingly long time to be incommunicado. And while NASA is outwardly confident that communications will be restored, there’s no way to be sure until we actually get to October and see what happens. Fingers crossed.

Listening In On A Deep-Space Satellite As It Returns Home

July 13, 2023 by Dan Maloney 1 Comment

We’ve covered dozens of projects about getting images of Earth’s weather straight from the source. It’s not too much of a trick to download images straight from our constellation of weather satellites, but what about space weather? We’ve got satellites for that too, of course, but to get a good look at the Sun, they’re out of reach of most homebrew ground stations.

That’s about to change, though, as STEREO-A returns to our neighborhood after a 17-year absence, making citizen science a reasonable proposition. The STEREO mission — Solar Terrestrial Relations Observatory — was launched in 2006 with a pair of satellites in heliocentric orbits. STEREO-B was lost in 2014 due to a navigational glitch, but STEREO-A has spent a lot of the intervening years watching the backside of the Sun relative to the Earth. As [Scott Tilley] explains, the satellite is now approaching inferior conjunction, where it will pass between the Earth and the Sun.

This close pass makes STEREO-A’s X-band deep-space beacon readily available to hobbyist-scale equipment, like [Scott]’s 66-cm dish antenna. The dish is mounted on an alt-az telescope mount for tracking, and sports a host of gear at the focus, like LNAs, filters, mixers, and an Ettus B200 SDR. It’s not a cheap setup, but compared to what’s usually needed to listen to STEREO-A, it’s a bargain. The process of demodulating and decoding the signals was a bit more involved, though, requiring not only SatDump and some custom code but also a lot of patience. The images are worth the wait, though; [Scott] shares some amazing shots of our increasingly active Sun as well as animations of recent sunspot activity.

If you’re interested in getting in on the STEREO-A action, you’d better get hopping — the satellite will only be in the neighborhood for a few more months before heading off for another pass around the back of the Sun.

THP Semifinalist: Cheap Satellite Transponder

September 20, 2014 by Brian Benchoff 7 Comments

In 2016, a communications satellite will be launched into geostationary orbit somewhere over the middle east. Normally, this is fairly ordinary occurrence. This satellite, however, will be carrying two amateur radio transponders for hams all across europe, africa, the middle east, and India. [2FTG] is building a satellite transponder to talk to this satellite, and he’s doing it with junk sitting around his workbench.

The uplink frequency for this satellite will be in the neighborhood of 2.4 GHz, and [2FTG] needed a way to deal with the out of band interference in this part of the spectrum. The easy and cheap way to do this is with filters made for the WiFi band. Instead, [2FTG] had a few cavity filters in his junk box and decided to go that route. It meant he had to retune the filters, a process that should be annoyingly hard. [2FTG] did it in thirty minutes.

Antennas are another matter, but since [2FTG] has a supply of metal coffee cans, this part of the build was just a matter of soldering a bit of wire to an SMA connector, drilling a hole (using a log as a drill stop, no less), and soldering the connector to the can.

The project featured in this post is a quarterfinalist in The Hackaday Prize.