Student Satellite to Hitch Ride With John Glenn
By Petty Officer 1st Class Diane Jacobs
American Forces Press Service
MONTEREY, Calif., March 11, 1998 When John Glenn makes his historic return to space after 36 years this October, another, yet smaller feat will also make history. The Navy's first amateur satellite -- designed and built by students at the Naval Postgraduate School -- will hitchhike on the same space shuttle mission.
The Petite Amateur Navy Satellite has been at the heart of student-driven research since its pen-and-paper conception in 1989 and is the thesis work of close to 60 students.
Measuring about two feet wide, and weighing 150 pounds, the communications satellite will orbit the Earth once every 95 minutes to provide communications using ham radio, and serve as a space-based laboratory for students in the space systems engineering and space systems operations section of the postgraduate school.
"We're designing and building everything. There's only two things we went out and bought: solar cells and batteries," said Dan Sakoda systems engineer for the project. "Every circuit board was designed here, and all components down to smallest level was selected, purchased and soldered into the boards. I don't think any other university does that."
While past students created the satellite's hardware, current student Navy Lt. Ken Hunter has invested 15 months to develop the satellite's user service software.
"This performs the communications functionality in the software," he said. "Not only do I have to do the satellite's software, but also the ground station software, which is a network of computers. It's a lot larger project than I first anticipated."
Hunter had to start from scratch, learning the basics of computer software. It took five months "just to get comfortable enough to do anything," he admitted. And, he didn't quite make the "grandiose plans" he originally intended either.
"When I finish, it will be working, and provide all functionalities. It just won't have a lot of the bells and whistles," he said. "But, I'll have those bells and whistles already designed, so a new student can come in and put them in."
Hunter, who graduates this month with a master's degree in computer science, added that his work actually doesn't go up with the satellite. Once the satellite is launched and orbiting, his software is sent up, and then it becomes operational.
Okay, once this satellite is up orbiting the Earth with its student-designed software and hardware, what about a computer "crash?"
The engineers and students have thought this through, too. One field Hunter studied was "fault tolerance" and how software can correct itself.
"I've figured that if something happens with the program, you just can't reach up and press 'Control, Alt, Delete.' So, I've designed the software to detect errors as they occur and fix the simple errors on its own. For a complicated error, it will notify someone down here for remote repair. It's a bit of artificial intelligence -- it's self-aware to see when something's wrong," Hunter said.
Sakoda said the space shuttle mission that will launch the satellite is primarily to support research with the Hubble Telescope. He considered this a piece of good luck for the student satellite, since it, too, is then assigned a high-altitude orbit. "This means there's more distance to fall, and a longer time to return to Earth," he said. He figures the satellite will remain in orbit between four to six years.
Students can add software, make adjustments, and upload or download information when the satellite orbits within a two-to-eight-minute window over the ground station in Monterey.
"Students really gain a lot as far as getting the big picture of a space system development. They're not just getting a master's degree in designing a filter, or software. They see the whole spectrum, the life cycle of development," said Sakoda. "No one said, 'Build us a small communications satellite.' We looked at the curriculum, and looked for something that could fill a void and get students that span across this highly inter-disciplinary type of curriculum. Students who come through our curric will be able to fly the spacecraft. You don't get this kind of opportunity elsewhere."
Sakoda predicts this program will continue, especially since its sponsors -- the Naval Space Command, and Space and Naval Warfare Systems Command -- support such education.
As for the Navy, said Hunter, which uses a lot of satellite systems, this may be the start of a new way of thinking.
"The Navy's leasing and using some aging satellites. We're looking at using small, cheap spectrum satellites," he said. "A network of these could replace the existing satellite infrastructure."
(Jacobs is a journalist at the Naval Postgraduate School)