They’re calling it the first space time capsule. Under the mantle of the University of Michigan’s Bicentennial, a team of students will launch a small satellite called a CubeSat, containing interviews from 1,000 members of the U-M community and an experiment to test DNA as a medium for storing data in space. Their goal is to build a satellite that can orbit the Earth for 100 years—the first U-M CubeSat built with a propulsion system.
The Michigan Bicentennial Archive (M-BARC) team believes that time capsules should not be left buried in the ground. “Like history itself, a time capsule should be alive, a thing of power and will. It should wrestle against the laws of nature and in turn its recipients must do the same. M-BARC will not sit dormant for a century, but rather send our successors on a glorious chase, and they must emerge triumphant to hear our voices.”
The issue with storing 1,000 interviews in a satellite is physical space and storage without protection from radiation. Radiation wreaks havoc on digital data, flipping their bits. Physically printed data like CDs are safe, but too big. So the team is working with the Lurie Nanofabrication Facility to nanoprint 8 to 30 GB of data on a 1-inch silicon chip. At least ten chips will be placed at different orientations in the satellite to provide backups in case of collisions.
Radiation also plays an important role in the team’s DNA radiation experiment, which tests the genetic code’s ability to store information in space. One microgram of DNA can hold 900 terabytes of data. That’s about 11,000 iPhones. The team had tried to encode the Michigan fight song into the DNA but according to Christopher Twilling, team lead of sequencing, because “the fight song is redundant within itself, it read like cancer to the DNA.” Instead, they are using the University of Michigan mission statement.
Future U-M scientists can see how well the synthetic DNA holds up. “They’ll know exactly what the sequence should be. When we get the satellite back, we can see how messed up it is over 100 years,” said faculty lead Aaron Ridley, a professor in the Department of Climate and Space Sciences and Engineering.
If it sounds like building the satellite is the easiest part, maybe it would’ve been—if it didn’t need to stay in Earth’s orbit for a century. From the moment it launches, the satellite’s orbit would start to decay. It wouldn’t last twenty years, let alone for one hundred, without a propulsion system.
“Small satellites typically don’t have propulsion,” Ridley said. “There’s just not room for a lot of fuel.” The team is currently comparing electric and chemical thruster systems for use in the CubeSat.
The original idea for M-BARC was to design the payload and send the time capsule to the moon, an idea proposed by Dr. Thomas Zurbuchen, a former U-M planetary science professor who is now now head of NASA’s Science Directorate. “It’s probably why it was so appealing to the engineering students—it was achievable!” said Kevin Tebbe (MSE AERO 16’), former student lead and one of five founding team members who worked on feasibility studies.
As the team grew to 30 students across 20 majors as part of the Multidisciplinary Design Program, ambitions for the project grew; they took on the bigger challenge of designing the satellite and orbit pattern themselves, in addition to the ISR-approved DNA experiment and the capture and encoding of 1,000 interviews. Finishing all of them in concert over the next two years requires the continued, persistent progress from students in engineering, science, and liberal arts disciplines as well as the expertise of faculty, staff and scientists across the globe.
The team expects construction of at least the payload portion of the CubeSat to begin in the middle of the Winter 2017 semester. The payload includes the DNA experiment and data chips containing interviews.
M-BARC will actually launch two satellites. The first, expected in late 2017, is a test satellite, about a third of the size of the eventual CubeSat.The students recently received a free launch for their test satellite from the United Launch Alliance, worth approximately $150,000. As part of their launch grant, they are working with students from Ypsilanti High School’s STEMP Middle College, home of a highly competitive FIRST Robotics program. While UM students work to build the electrical and most of the structural components of the satellite, the high school students will be assisting with the satellite’s structural fabrication.
Ultimately, in the next century, U-M hopes to retrieve the time-capsule by using a laser to find the satellite’s built-in reflectors.