Cowing teamed up with Dennis Wingo, the CEO of Skycorp, which develops low-cost space technology using creative design and manufacturing processes. It’s not the first time Cowing and Wingo have worked together to recover vintage NASA assets. The duo are the driving force behind the Lunar Orbiter Image Recovery project, an effort to restore original photographs taken by the five Lunar Orbiter spacecraft sent to the moon in 1966 and 1967 ahead of the Apollo astronauts. The LOIRP team has recovered and cleaned up numerous unique views of the moon, including the famous first “Earthrise” photo captured by Lunar Orbiter 1 in 1967. Both the Lunar Orbiter Image Recovery Project and ISEE-3 Reboot Project are headquartered at McMoons, a repurposed McDonald’s located on grounds of NASA’s Ames Research Center.

The ISEE crowdfunding effort, which raised nearly $160,000 through RocketHub, has been called a citizen science effort. Cowing isn’t a huge fan of the term. “Citizen science sounds like a fancy way to say amateurs,” he said. “Bob Farquhar is on our team. Mike Loucks, from LADEE [NASA’s Lunar Atmosphere and Dust Environment Explorer spacecraft] is on our team. I designed spacecraft back in the day; so has Dennis, so it’s not like we don’t know what we’re talking about.”

After a long effort to cut through remaining red tape, Cowing and Wingo received the official go-ahead from NASA on May 21. The ISEE-3 Reboot Project was permitted to move forward.

How to talk to a 36-year-old spacecraft

Because the original hardware used to contact ISEE-3 was thrown out decades ago, the ISEE-3 team needed to find a new way to communicate with the spacecraft. They wouldn’t be able to spend the millions NASA was quoting to rebuild original hardware from scratch, so they turned to an alternative: Software Defined Radio (SDR).

“Radios have traditionally been built using ‘black-box’ designs,” said Balint Seeber, an applications specialist and SDR evangelist for Ettus Research, which specializes in the technology. “They are built against specific specifications to serve a specific purpose, and they will only understand or generate signals of a particular kind.”

Seeber was brought on board to help with the ISEE project. He said small SDR boxes are often “orders of magnitude” cheaper than the original hardware they replace. The devices take a raw radio signal and feed it to a connected computer. Using a free, open-source software package called GNU Radio, any run-of-the-mill computer can interpret the signal and decode it according to specifications the user enters. Whereas the interpretation of ISEE's radio signals used to be done using bulky hardware, it can now be achieved virtually.

Likewise, when the ISEE team needs to transmit a command to the spacecraft, they use GNU Radio to input NASA’s original communications specifications. “You feed it the raw ones and zeroes that only the spacecraft knows how to interpret,” Seeber explained. The SDR box translates the ones and zeroes into a radio signal, and sends the signal to a transmitter, where it is beamed into deep space toward ISEE.

All of this requires a really big satellite dish, so the ISEE team teamed up with Arecibo Observatory in Puerto Rico. Arecibo is typically used to study astronomical, planetary and atmospheric phenomena, but it is also versatile enough to regain control of wayward spacecraft.