In 1965, the US Air Force and the Lincoln Laboratory at MIT launched two Lincoln Experimental Satellites (LES) into orbit around the Earth: LES-1 and LES-2.<\/p>\n
These were the first super-high-frequency satellites, using the X-band of the electromagnetic spectrum.<\/p>\n
“Lincoln Laboratory\u2019s space communications program after Project West Ford began in 1963 with a charter to build and demonstrate military space communications systems. The initial program objective was to build, launch, and field a LES and a LET [Lincoln Experimental Terminals] that would work together as a system and demonstrate practical military satellite communications,” NASA’s History Office explains<\/a> of the project, which had mixed success.<\/p>\n “LES-1, launched from Cape Canaveral on 11 February 1965, accomplished only a few of its objectives,” NASA adds.\u00a0“Apparently because of miswiring of the ordnance circuitry, the satellite never left circular orbit and ceased transmitting in 1967. LES-2, the twin of LES-1, fared much better; it achieved its planned final orbit on 6 May 1965.”<\/p>\n LES-1, no longer sending any signals, continued on its orbit around the Earth for nearly half a century, another piece of dead space junk littering up Earth’s orbit. But in 2013, an amateur radio astronomer in Cornwall, UK, picked up a signal that could only be from LES-1. It had become what is known as a “zombie satellite”; satellites that \u2013 sometimes mysteriously<\/a> \u2013 become active once more.<\/p>\n<\/p>\n According to Phil Williams, who found the space zombie, the signal coming from the satellite faded in and out on a four-second loop. He attributed this to LES-1 tumbling on its end every four seconds, with the engines blocking its solar panels.<\/p>\n “This gives the signal a particularly ghostly sound as the voltage from the solar panels fluctuates,” Williams said at the time<\/a>.<\/p>\n \u00a0\u00a0\u00a0<\/p>\n After the satellite came back to life, a team from the Lincoln Laboratory set up a system to record LES-1 every time it passed over the main university campus.<\/p>\n “LES-1 is one of the oldest satellites in space and part of Lincoln Laboratory’s legacy in SATCOM [satellite communications], so to see it still transmitting after all these years is remarkable,” Navid Yazdani, leader of the Laboratory’s Advanced SATCOM Systems and Operations Group, said in a statement<\/a>. “LES-1 introduced several innovative SATCOM technologies and techniques for its time, and lessons learned during the launch and testing of LES-1 enabled engineers to refine the design of subsequent experimental satellites that paved the way for future military and civil systems.”<\/p>\n So, what caused this satellite to go zombie mode? We aren’t entirely sure, but of course, it is nothing to worry about.<\/p>\n “Though we don’t know for certain why this ‘zombie’ satellite came back to life, one possibility is that LES-1 experienced an electrical short (caused by its batteries or circuitry degrading over time), allowing power from its solar cells to directly reach the transmitter,” the Lincoln Laboratory explains.\u00a0<\/p>\n