Launched by the National Aeronautics and Space Administration (NASA) in 1978, the International Sun-Earth Explorer-3 (ISEE-3) was the first spacecraft to measure the solar wind, a high-speed stream of electrons and protons released from the sun’s atmosphere, as it approaches Earth. In the mid-1980s, ISEE-3 became the first spacecraft to fly past a comet. But NASA stopped using the spacecraft in 1997, and since then it has been looping around the sun, waiting for a command that never came. Now, a group of civilians is working to reestablish contact with the vintage spacecraft and bring it home.
By orbiting the sun between the sun and Earth, the 1970s-era spacecraft dubbed ISEE-3 enabled scientists the unprecedented ability to observe the solar wind before it reached Earth. At the suggestion of the craft’s flight director, Dr. Robert W. Farquhar, ISEE-3 was then aimed at Comet Giacobini-Zinner, and passed through its tail in September 1985. After that, the craft was used for a few more observations of interplanetary space before 1997, when NASA shut it down. According to Dr. Farquhar’s estimates, ISEE-3 was on course to travel about 30 miles above the surface of the moon on August 10, 2014. The gravitational pull of this lunar encounter would be enough to pull the craft into Earth’s orbit, when (as Dr. Farquhar suggested) a space shuttle could bring it home.
But in 1999, all the transmitters that could communicate with ISEE-3 were discarded when NASA upgraded its system of radio telescopes, known as the Deep Space Network. With no way of talking to the craft, the likelihood of bringing it back to Earth seemed dim. In 2008, the Deep Space Network managed to listen briefly at its far-flung location and heard the carrier frequency of the spacecraft’s radio, which was never turned off and still awaited its next command from Earth.
Though supporters of ISEE-3 argued it could be used to train future scientists and engineers, NASA concluded it wasn’t worth the expense or effort to revive communications with the craft for the occasion of the 2014 lunar fly-by. That’s when Dennis Wingo and his company, Skycorp, stepped in to accept the challenge. With the help of Keith Cowing, editor of the Web site NASA Watch, and about 20 other people across the country (including many members of the original ISEE-3 team), Wingo raised $160,000 from more than 2,200 donors to help pay the costs of the project. Wingo, an engineer and entrepreneur, had previously teamed with Cowing to take on another task NASA considered unfeasible: extracting high-resolution images taken by the administration’s lunar orbiters in the 1960s from 50-year-old magnetic tapes. Of taking on the ISEE-3 project, he told the New York Times: “No one else was going to do it, and it seemed like the right thing to do.”
Wingo and his team of “techno-archaeologists” have been working out of a former McDonald’s restaurant on a closed Navy base outside San Jose, California, which NASA converted to a research campus for small tech companies, nonprofits and academics. They began their project in April, and made a breakthrough last month, when they were able to talk to ISEE-3 using the Arecibo Observatory radio telescope in Puerto Rico. With that achievement, Skycorp became the first private organization to command a spacecraft outside Earth’s orbit.
After signing an agreement with NASA, Wingo’s team was able to benefit from recent advances in so-called software-defined radios, which enabled them to build and install a new transmitter on Arecibo telescope within a few weeks, much more quickly and cheaply than was possible before. The ship appears to be in good working order, though the challenge now lies in figuring out how to command it, as no one has access to a full operational manual. Now Wingo has persuaded NASA to use the Deep Space Network to determine the craft’s exact trajectory and calculate the rocket burn required to put it on a path to Earth’s orbit. In a couple of weeks, if all goes as planned, the engines will fire up and the “zombie spaceship” (as the Times calls it) will head home.