After Eight-Month Break, Deep Space Network Reconnects With Voyager 2

When the news broke recently that communications had finally been re-established with Voyager 2, I felt a momentary surge of panic. I’ve literally been following the Voyager missions since the twin space probes launched back in 1977, and I’ve been dreading the inevitable day when the last little bit of plutonium in their radioisotope thermal generators decays to the point that they’re no longer able to talk to us, and they go silent in the abyss of interstellar space. According to these headlines, Voyager 2 had stopped communicating for eight months — could this be a quick nap before the final sleep?

Thankfully, no. It turns out that the recent blackout to our most distant outpost of human engineering was completely expected, and completely Earth-side. Upgrades and maintenance were performed on the Deep Space Network antennas that are needed to talk to Voyager. But that left me with a question: What about the rest of the DSN? Could they have not picked up the slack and kept us in touch with Voyager as it sails through interstellar space? The answer to that is an interesting combination of RF engineering and orbital dynamics.

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It Came From Outer Space: Listening To The Deep Space Network

Ham radio operators love to push the boundaries of their equipment. A new ham may start out by making a local contact three miles away on the 2m band, then talk to somebody a few hundred miles away on 20m. Before long, they may find themselves chatting to fellow operators 12,000 miles away on 160m. Some of the adventurous return to 2m and try to carry out long-distance conversations by bouncing signals off of the Moon, waiting for the signal to travel 480,000 miles before returning to Earth. And then some take it several steps further when they listen to signals from spacecraft 9.4 million miles away.

That’s exactly what [David Prutchi] set out to do when he started building a system to listen to the Deep Space Network (DSN) last year. The DSN is NASA’s worldwide antenna system, designed to relay signals to and from spacecraft that have strayed far from home. The system communicates with tons of inanimate explorers Earth has sent out over the years, including Voyager 1 & 2, Juno, and the Mars Reconnaissance Orbiter. Because the craft are transmitting weak signals over a great distance (Voyager 1 is 14 billion miles away!), the earth-based antennas need to be big. Real big. Each of the DSN’s three international facilities houses several massive dishes designed to capture these whispers from beyond the atmosphere — and yet, [David] was able to receive signals in his back yard.

Sporting a stunning X-band antenna array, a whole bunch of feedlines, and some tracking software, he’s managed to eavesdrop on a handful of spacecraft phoning home via the DSN. He heard the first, Bepi-Colombo, in May 2020, and has only improved his system since then. Next up, he hopes to find Juno, and decode the signals he receives to actually look at the data that’s being sent back from space.

We’ve seen a small group of enthusiasts listen in on the DSN before, but [David]’s excellent documentation should provide a fantastic starting point for anybody else interested in doing some interstellar snooping.

NASA Making Big Upgrades To Their Big Dish DSS43

When it comes to antenna projects, we usually cover little ones here. From copper traces on a circuit board to hand-made units for ham radio. But every once in a while it’s fun to look at the opposite end of the spectrum, and anyone who craves such change of pace should check out DSS43’s upgrade currently underway.

Part of NASA’s Deep Space Network (DSN) built to communicate with spacecraft that venture far beyond Earth, Deep Space Station 43 is a large dish antenna with a diameter of 70 meters and largest of the Canberra, Australia DSN complex. However, the raw reflective surface area is only as good as the radio equipment at its center, which are now outdated and thus focus of this round of upgrades.

The NASA page linked above offers a few pieces of fun trivia about DSS43 and its capabilities. If that whets an appetite for more, head over to Twitter for a huge treasure trove. Whoever is in charge of Canberra DSN’s Twitter account has an endless fountain of facts and very eager to share them in response to questions, usually tagged with #DSS43. Example: the weight of DSS43 is roughly 8.5 million kilograms, 4 million of which is moving structure. They also shared time lapse video clips of work in progress, one of which is embedded after the break.

Taking the uniquely capable DSS43 offline for upgrades does have some consequences, one of which is losing our ability to send commands to distant interplanetary probe Voyager 2. (Apparently smaller DSN dishes can be arrayed to receive data, but only DSS43 can send commands.) Such sacrifices are necessary as an investment for the future, with upgrade completion scheduled for January 2021. Just in time to help support Perseverance (formerly “Mars 2020”) rover‘s arrival in February and many more missions for years to come.

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Clock Monitors Deep Space Network, Keeps Vigil Over Lost Mars Rover

It’s been a long, long time since we heard from Opportunity, the remarkable Mars rover that has shattered all expectations on endurance and productivity but has been silent since a planet-wide dust storm blotted out the Sun and left it starved for power. Right now, it’s perched on the edge of a crater on Mars, waiting for enough sunlight to charge its batteries so it can call home. All we can do is sit, and wait.

To pass the time until Opportunity stirs again, [G4lile0] built this Deep Space Network clock. Built around an ESP32 and a TFT display, the clock monitors the Deep Space Network (DSN) website to see if mission control is using any of the huge antennas at its disposal to listen for signals from the marooned rover. If the DSN is listening, it displays a special animation exhorting the rover to phone home; otherwise, it shows which of the many far-flung probes the network is communicating with, along with a slideshow of Mars mission photos to keep the spirits up. When the day finally comes that Opportunity checks in, an alarm will sound so [G4lile0] can pop the champagne and celebrate with the rest of us.

We realize that the odds that Opportunity will survive this ordeal are decreasing by the Sol. It’s an uphill battle; after all, the machine was 55 times its original 90-day design life when it went dark, so it’s an uphill battle. Then again, it has beaten the odds before, so there’s still hope.

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Serious DX: The Deep Space Network

Humanity has been a spacefaring species for barely sixty years now. In that brief time, we’ve fairly mastered the business of putting objects into orbit around the Earth, and done so with such gusto that a cloud of both useful and useless objects now surrounds us. Communicating with satellites in Earth orbit is almost trivial; your phone is probably listening to at least half a dozen geosynchronous GPS birds right now, and any ham radio operator can chat with the astronauts aboard the ISS with nothing more that a $30 handy-talkie and a homemade antenna.

But once our spacecraft get much beyond geosynchronous orbit, communications get a little dicier. The inverse square law and the limited power budget available to most interplanetary craft exact a toll on how much RF energy can be sent back home. And yet the science of these missions demands a reliable connection with enough bandwidth to both control the spacecraft and to retrieve its precious cargo of data. That requires a powerful radio network with some mighty big ears, but as we’ll see, NASA isn’t the only one listening to what’s happening out in deep space. Continue reading “Serious DX: The Deep Space Network”

Talking To ISEE-3

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ISEE-3, the plucky interplanetary spacecraft fueled by the dreams of thousands of crowdfunding backers and hydrazine is now transmitting data to Earth.

Where all radio contact with ISEE-3 this year has only been a carrier frequency, the folks at the reboot project have successfully commanded ISSE via the huge Arecibo telescope to transmit data back to Earth. Usable data are now being received at 512 bits/second at ground stations in Germany, Kentucky, and California, surely being looked over by the ISEE reboot project engineers.

Simply transmitting the commands to put the data multiplexers into their engineering telemetry mode was no small task; a power amplifier needed to be built, shipped to Arecibo, and installed in the giant dome hanging over the Arecibo dish. The amplifier was only installed in the last day, during an earthquake, no less.

There’s still a lot of work to be done before the project can go any further; the team will need to check the status of the spacecraft from the data received, more systems will be checked out, and eventually the spacecraft will be commanded to perform a 17-hour long burn with its small thrusters, putting it on course to be captured by Earth some time in August.

It’s an amazing achievement to do any sort of communication on this scale, and now events in the ISEE-3 mission timeline will be coming rather quickly. We’re trying to organize a video/blog/cast thing with the team from NASA Ames or Morehead State, but the team is, understandably, a little busy right now.

ISEE-3: We Get Signal

ISSE-3

Out in the depths of space, more than 100 times the distance from the Earth to the moon, there’s a lonely spacecraft gracefully spinning towards an August encounter with our planet. It’s ICE/ISEE-3, a probe long-forgotten by official space agencies. Now, the team dedicated to repurposing this satellite has made contact with this probe using a 20-meter satellite dish in Germany.

When we first heard about the planned communication by volunteers, no one was certain the probe was still alive. It shouldn’t be a surprise this satellite was still functioning; it was launched in 1978, and most of the instruments were still functioning in 2008. Still, this is the first time amateurs – not NASA – had received a signal from the probe

ICEteam, the group of volunteers dedicated to reviving this spacecraft used the huge dish at Boshum observatory to detect the 5 Watt carrier signal coming from the spacecraft. That’s all the probe is sending out right now – no data was received – but this is a huge accomplishment and the first step towards directing ICE/ISEE-3 into an orbit around one of the Earth-Sun Lagrange points.

Side note: Looking at the ephemeris data (target -111) I *think* ICE/ISEE-3 will be above the night side of Earth at closest approach. Can anyone confirm that, and does that mean a future mission at L2?

Video from the ICEteam below.

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