The satellites found unencrypted data, including phone calls and some military communications

Security researchers have discovered that as many as half of all geostationary satellites in Earth orbit carry sensitive unencrypted information for consumers, businesses and the military, leaving this data wide open to eavesdropping.

Researchers at UC San Diego and the University of Maryland spent $800 on an off-the-shelf satellite receiver and pointed it skyward for three years. They found large amounts of unencrypted data traveling to and from space, including people’s private voice calls and text messages, and consumer Internet traffic from onboard Wi-Fi services.

The unencrypted data also included communications between critical infrastructure systems, such as energy and water suppliers, and offshore oil and gas platforms, according to Wiredwhich was first published The results reached by the researchers.

Researchers spent the past year alerting affected organizations to this exposure, including T-Mobile and AT&T’s network in Mexico, which began encrypting its data soon after to prevent future eavesdropping.

But researchers warn that not everyone has been able to process their exposed data, including some critical infrastructure providers, and that large amounts of satellite data will be exposed for several years to come.