12 Satellites Sending Signals From Empty Space
This listicle highlights 12 satellites that continue to send signals through the depths of space, revealing how these enduring machines keep communicating long after their missions were thought to be over.
- Daisy Montero
- 4 min read
Orbiting high above Earth, some satellites keep sending signals long after their missions should have ended. Others beam mysterious data that scientists still struggle to decode. These silent travelers tell a story about how technology and time can outlast human plans.
1. 1. The Aged but Active Voyager 1
NASA/JPL on Wikimedia Commons
Launched in 1977, Voyager 1 is still transmitting data across billions of miles. Its faint signal travels through interstellar space, taking over 22 hours to reach Earth. Scientists continue to receive updates about cosmic rays and magnetic fields. Even after all these years, it keeps whispering secrets from beyond our solar system.
2. 2. The Persistent Echo of LES-1 Slide Description:
USAF on Wikimedia Commons
LES-1 was launched in the 1960s and lost contact after a malfunction. Decades later, amateur radio operators picked up its signal again in 2013. Its weak transmission stunned experts who thought it was dead. Somehow, its ancient circuits kept working, sending an eerie reminder of the past.
3. 3. NASA’s Long-Lived TDRS-3
NASA/Jim Grossmann on Wikimedia Commons
The Tracking and Data Relay Satellite 3 was launched in 1988 and still sends occasional test signals. It helped link astronauts and ground control during shuttle missions. Even though it has been replaced, engineers keep it in standby mode. Its continued operation proves how durable early satellite technology can be.
4. 4. The Mystery of “ZombieSat” Galaxy 15
ZombieSat on Wikimedia Commons
In 2010, Galaxy 15 lost control but kept broadcasting TV signals. Engineers could not steer it, yet it kept transmitting as if nothing was wrong. It drifted freely, earning the nickname “ZombieSat.” Months later, it unexpectedly recovered on its own, continuing to puzzle satellite operators.
5. 5. The Unending Pulse of Vanguard 1
Daderot on Wikimedia Commons
Vanguard 1, launched in 1958, stopped sending data in 1964 but continues to orbit Earth today. It once transmitted valuable information about the planet’s shape and atmosphere. Despite its silence, radio enthusiasts continue scanning for a sign of life. Its survival makes it one of humanity’s oldest space relics.
6. 6. The Enigmatic “Black Knight” Signal
Veedar at English Wikipedia on Wikimedia Commons
For years, radio operators have claimed to detect signals from an unknown satellite dubbed the “Black Knight.” Some believe it is debris, while others think it is an unregistered probe. Its strange behavior has fueled many theories and conspiracies. Whether real or mistaken, its legend continues to echo across space forums.
7. 7. The Drifting Pioneer 10
NASA Ames Research Center on Wikimedia Commons
Pioneer 10 was launched in 1972 and was the first to travel beyond Jupiter. It sent its last signal in 2003, but some receivers still attempt to hear its faint pulse. Its mission plaque carries a message for any intelligent life that might find it. Though silent now, it remains a symbol of human reach.
8. 8. The Forgotten EchoStar 3
(Credit: NASA/CXC/M.Weiss) on Wikimedia Commons
EchoStar 3 once broadcast television signals across North America. When it stopped responding to control commands, it continued drifting in geostationary orbit. Occasionally, faint transmissions have been detected from its transponders. Its quiet persistence is a reminder that space never fully lets go of its machines.
9. 9. The Still-Talking Hubble Space Telescope
Hubble ESA on Wikimedia Commons
Hubble has been orbiting since 1990 and still transmits stunning images of distant galaxies. Even after several repairs, it keeps functioning beyond expectations. Engineers receive constant signals to fine-tune their instruments. It continues to send humanity glimpses of the farthest corners of the universe.
10. 10. The Outlasting Transit 5B-5
U.S. Navy on Wikimedia Commons
Transit 5B-5 was a navigation satellite launched in the 1960s. It was one of the first nuclear-powered satellites. Though its mission ended decades ago, it still emits weak signals picked up by some stations. It remains a fascinating relic of Cold War-era technology that refuses to fade.
11. 11. The Continuous Chirp of ACRIMSAT
NASA / JPL on Wikimedia Commons
Launched in 1999, ACRIMSAT measured solar radiation for over a decade. After losing contact in 2013, faint signals were still occasionally detected. Its body remains intact in orbit, circling Earth quietly. Scientists honor its service as one of NASA’s most efficient solar missions.
12. 12. The Living Legacy of NOAA-9
National Oceanic and Atmospheric Administration on Wikimedia Commons
NOAA-9 launched in 1984 and monitored weather systems across the globe. Even after being replaced, it sometimes sends ghost signals due to battery surges. Amateur radio enthusiasts have confirmed these occasional bursts. Its unplanned endurance shows how space hardware can surprise even decades later.