There’s always that one guy, and on February 10 that guy was amateur operator Scott Tilley, VE7TIL, snagging a hard-to-get signal from China’s Tianwen-1 probe as it orbited Mars. It’s no small feat to track down a spacecraft signal, but Ham hobbyist Tilley, who intrepidly stalks what he calls “zombie satellites” in deep space, is practically a pro.
While Tianwen-1 did post its frequency with the International Telecommunication Union (ITU), the information was not specific enough for precise tuning (X-band between 8 GHz and 12GHz)—so the real work began. Tilley told Spaceweather.com that “it was like a treasure hunt” to locate the signal, but once found the X-band signal from Tianwen-1 (that you can listen to HERE) was “loud and audible.” Tienwen-1 is part of China’s first mission to Mars and consists of an orbiter and rover that are scheduled to land on the Red Planet in May or June of this year.
Tilley is no stranger to deep space searches. He found the signature of IMAGE (Imager for Magnetopause-to-Aurora Global Expedition) in 2018—a thrilling discovery for scientists who had declared the NASA spacecraft dead as of 2005. Then in 2020, he identified signals from the experimental UHF military communication satellite LES-5. Launched in 1967, the satellite was shut down in 1972 but is still able to operate without assistance as long as its solar panels are facing the sun—which, as Tilley found out, they most certainly still are.
But how is this type of extreme DXing possible? According to Tilley, “It helps to have a big antenna, but the real key is the advent of Software Defined Radios (SDRs).” SDRs are cheap, sensitive, and provide fine-tuned control over frequency that’s great for tuning into spacecrafts—even ones more than 200 million kilometers away in deep space. Tilley also uses a homemade 60-centimeter dish. Using just this equipment, he has recently been able to pick up signals from NASA’s Mars Reconnaissance Orbiter and the United Arab Emirates Hope probe—both of which currently orbit Mars.
