One student satellite is set to launch; another may fly
By Michael Gillis
Inside an air force “clean tent” at Kirtland Air Force Base in New Mexico is a small collection of hardware easy to overlook. Stacked there are two hexagonal structures weighing about 110 pounds, easily lost in the dizzying array of sophisticated military hardware. But to hundreds of Cornell students, staff, and aerospace professionals, that small package represents a real shot at advancing satellite technology.The two pieces of equipment are CUSat. This matched pair was Cornell’s 2005 entry in the University Nanosat Program’s Nanosat-4 competition, sponsored by the U.S. Air Force and the American Institute of Aeronautics and Astronautics. CUSat won the competition, which, in addition to a $110,000 grant to make the satellites spaceworthy, includes a ticket into space. The program aims to foster student satellite research and design, construction, and flight.
Mason Peck, associate professor of mechanical and aerospace engineering, said the time between victory and the launch pad can be years, a long and anxious wait to test a spacecraft’s mettle. But the wait is nearly over for the CUSat team. The experimental spacecraft is now booked—or manifested—for its one-way flight later this year aboard a SpaceX Falcon 9 rocket. That’s exciting news for Peck and the team that has spent years working on the project.
An idea takes flight
|The CUSat spacecraft hangs from a crane before being moved into a thermal vacuum chamber for testing at the Air Force’s Aerospace Engineering Facility in Albuquerque, N.M.|
Once in orbit, CUSat’s two identical satellites will navigate with the help of global positioning satellite data to inspect each other with cameras and beam that data back to Cornell for evaluation. Peck said that kind of precise inspection of spacecraft could prove invaluable to a host of future manned and unmanned missions.
“What’s important here is how CUSat does the inspection,” Peck said. “It doesn’t just circumnavigate, just fly around the other spacecraft—it does do that—but it does so using GPS. In space, what GPS offers is relative position knowledge. CUSat has some innovative algorithms developed by Mark Psiaki, another professor at Cornell, that allow CUSat to know its position remote to something else to within millimeters of accuracy, which is an extremely fine precision.”
The implications of that level of precision are significant.
“If you had a satellite that could go from one to another geosynchronous satellite, for example, you might have the means to evaluate the health of, and maybe even fix, what amounts to very expensive assets,” Peck said.
That could include everything from commercial satellites to manned spacecraft.
There’s also a financial incentive.
“Geosynchronous satellites can cost hundreds of millions of dollars to build and tens of million dollars to launch,” he said “They make their operators millions of dollars a day, so there’s a lot of money at stake.”
CUSat was one of the first proposals Peck wrote when he arrived at Cornell in 2004. He said the project was envisioned as a way to merge some of Cornell’s faculty strengths, including those of Psiaki, a professor, and Mark Campbell, an associate professor, both in mechanical and aerospace engineering.
Psiaki’s unique GPS algorithms will help CUSat navigate precisely. Campbell’s design of pulsed-plasma thrusters to move the spacecraft were specially modified for CUSat, and each satellite contains eight of the thrusters.
That kind of expertise allowed CUSat to evolve and now, near the eve of the launch, the team can size up their success so far.
Peck said there are few university projects of this scope and its accomplishments reach a wider audience.
“CUSat turns out to be the most densely packed spacecraft the Air Force has ever seen,” Peck said. “It really is chock-full of good stuff. It’s two spacecraft merged together, so it’s two for one to begin with. Each spacecraft has eight thrusters. That’s a total of 16 thrusters for the entire package, a large number. Each spacecraft has three reaction wheels. Each has three GPS receivers, two radios, two antennas, and eight solar panels. The pair tolerates any single failure of its hardware. So, we’ve created a very robust space system.”
Just as significant, though, is ownership and student and faculty pride in the project.
“It’s very impressive that the CUSat program is able to produce spacecraft in such a short time and for such low cost, that are then able to compete side-by-side with satellites from other organizations in the industry,” said Justin Hahn ’08 ME, M.Eng. ’08 AE, who was CUSat’s propulsion subsystem lead, responsible for the design, assembly, and testing of CUSat’s pulsed plasma thrusters. He also led the entire CUSat team during his final year at Cornell. “Building a spacecraft that can stand up to these industry reviews is significantly different from many other student projects, so the success of CUSat indicates how well the rigorous space systems processes have been applied to the program. Although CUSat has demonstrated numerous other technical achievements in their various subsystems, I’m most impressed with the overall ability of the program to deliver flight-ready hardware.”
Once in orbit, Cornell’s role with CUSat will be far from over.
“It’s very much a Cornell-owned, self-contained project—we build it, we send it to the Air Force who launches it, we operate it, and we get the data,” Peck said. “So it’s very much a Cornell spacecraft.” In 2006, Campbell’s ICE Cubesats were the first Cornell spacecraft to be launched. Unfortunately, the launch vehicle exploded. So, if CUSat makes it to orbit, it will be Cornell’s first satellite.
A radio antenna on Mt. Pleasant in Ithaca, adjacent to the Hartung-Boothroyd Observatory, will link CUSat with the mission control center in the basement of Ward Hall. The CUSat team operates another ground station on the Kwajalein Atoll in the Pacific Ocean, which had been created for a previously planned CUSat launch that never happened.
Peck points out that enthusiasts won’t be able to spot CUSat in space—it’s simply too small—but can listen in.
“These will not be visible from the ground, probably not even with telescopes,” he said. “Instead, they’ll be in a low enough orbit that you’ll be able to pick up their transmissions using off-the-shelf radio equipment. Any radio hobbyist can easily listen in and pick up the transmissions.”
Not your typical homework problem
|A close-up of the ‘isogrid’ pattern machined into Violet’s structure. This gives the structure a high strength-to-weight ratio, necessary for surviving launch.|
There’s no denying that hands-on or experiential education is invaluable. However, that level of experience on a project such as CUSat can be daunting and challenging to even the most disciplined students.
“This is much more than simply a set of homework problems or even a garage mechanic’s kind of project,” Peck said. “This is the kind of activity where students get experience they’re not likely to get at any other university, and one that prepares them for a career in a way they won’t get elsewhere. They are learning the professional context for the more abstract engineering. They also get the sense of ownership, beyond simple interest, which helps mature them.”
That maturity, he added, is shaped by a recognition that if students fall short of their work on the project, there isn’t time for someone else to pick up the slack.
Graduate student Dan Milavitch ’10 EP, who is lead systems engineer on CUSat’s successor project, Violet, explains the challenge.
“Working with a group of young, inexperienced students is difficult for any project,” he said. “Working with a group of young, inexperienced students on the design and fabrication of a spacecraft is much harder. Now add a Cornell engineering workload to the mix and you start to see what we have to deal with here.”
However, Milavitch said that because the projects look to industry standards, the work directly relates to sought-after skills in the professional aerospace industry.
Simmie Berman ’06 ME understands. Berman worked on CUSat during her junior and senior years. She said the project was hard work, long hours, and a lot of fun. It was also some of the best practical experience she had, which helped plot a career course.
“Working on CUSat has had a direct impact on my current position,” she said. “I’m currently working as a mechanical engineer in the Space Department at the Johns Hopkins University Applied Physics Laboratory on the Radiation Belt Storm Probes. My experience on CUSat was a lot like my work experience, just on a smaller scale. We faced similar challenges on CUSat and on my current program, and I have been able to draw from that experience to help me figure out how to solve problems in my current work. Being familiar with a lot of the terminology, processes, and requirements of designing a satellite definitely was to my advantage when applying for my current position.”
Hahn, who is also at Johns Hopkins’ Applied Physics Laboratory, agrees.
“Working on CUSat directly prepared me for the job I have now and allowed me to come in with a ‘running start’ when I began work,” he said. “At a minimum, working on the project familiarized me with the basics of spacecraft engineering. When I started working here, I was already familiar with the process for designing and building a spacecraft as well as the subsystems involved. I also had a grasp of the terminology and vocabulary of spacecraft design and build.”
Hahn added the leadership experience gained from working with the team was a direct benefit to his professional career.
A bright future
|Members of the Violet team display their award plaques in their booth after the Nanosat-6 Flight Competition Review in Albuquerque, N.M. Left-to-right: Amanda Kuczun ’12 ME; William Bruey ’11 EP; Lucas Ackerman ’11 ECE; Dan Milavitch ’10 EP, M.Eng. ’10 SYSEN; MAE Assoc. Prof. Mason Peck; Stuart Jackson ’12 EP; M.Eng student Kevin Meissner ’10 ME; Benjamin Miller ’12 CS, EP; John Meluso ’13 EP; and Joshua Abeshaus ’12 ME.|
Cornell was not allowed to enter Nanosat-5 because of the victory in the previous competition. Violet, Cornell’s Nanosat-6 entry, won second place after a Flight Competition Review in January. Peck says the Air Force was impressed enough with the project that it may launch Violet regardless of the outcome of the competition.
Violet shares very little in common with CUSat, Peck said, the exception being the GPS receivers, built by Paul Kintner, the well-respected professor of electrical and computer engineering who died in November, 2010.
“It’s disappointing he never got to see his receivers on the satellite, but we’ll be doing that in remembrance of him,” Peck said.
Peck said Violet’s mission is to achieve unparalleled agility in space to improve imaging. Violet’s science team, led by astronomy Assistant Professor Jamie Lloyd, focused on ultraviolet astronomy.
“The ultraviolet data we’ll gather with the spectrometer will tell him information about the Earth’s atmosphere in a way that he can then use to calibrate how he might look at extrasolar planets,” Peck said.
And it will be fast.
“Violet will conduct experiments that show a very small satellite can actually move much faster than a larger satellite,” he said. “Violet, when you stretch its capabilities, should be able to rotate about 40 degrees per second. That’s faster than a race car and as fast as an athlete rotates in gymnastics.”
Violet will reach such speeds through the use of control moment gyroscopes (CMG) and the application of next-generation steering laws. CMGs have been used in spacecraft for decades, but not on such a small scale in nanosatellites, which, if successful, will increase efficiency and agility.
That kind of speed andagility could also provide financial benefits.
“I’ll give you an example,” Peck said. “Google Earth uses imagery from a spacecraft called GeoEye. It’s a spacecraft that moves as quickly as it can to point its cameras at different places on the earth and take as many relevant pictures as it can as it passes overhead in orbit. The GeoEye spacecraft moves only about a tenth as fast as Violet. So, because time is money, Violet represents a much more cost-effective use of those camera resources.”
Although the Violet mission differs from CUSat’s, it does share a critical component: teamwork.
M.Eng. student Kevin Meissner ’10 ME, the project lead for Violet, said the team’s showing at Nanosat-6 depended on coordination and teamwork.
“The team has been required to evolve as we’ve reached different stages in the project’s lifecycle,” he said. “When the team started, we had about 18 members, mostly underclassmen, all focusing on developing requirements, performing trade studies, and designing a spacecraft that can complete our mission. Since then, for the past year, the team has been deeply involved in design and analysis, fleshing out the detailed subsystem designs and performing the analyses required to ensure that our spacecraft can survive launch and the space environment. During that time the team has steadily grown in size. This semester the team moved into integration activities, and there were up to 55 members working nonstop to prepare our satellite for the flight competition review in January. Typical activities of the team included soldering, machining, writing software, and lots of testing.”
Even with such camaraderie on a project, the challenges remain.
“The most challenging thing for student satellite teams is typically just training the team in aerospace design and build practices,” Meissner said. “The problems you encounter and need to design for in space are very different from what you would encounter when designing something for terrestrial use, and it takes a while for new members to become familiar with these nuances. For that reason we started out with a very young team, mostly freshmen and sophomores, who we were able to thoroughly train. Since then the young team has matured and we were able to retain many of those early members. The continuity this provides is very important to building an efficient, knowledgeable team.”
Violet and CUSat clearly benefit students, but others benefit, too. For instance, Violet’s attitude control actuators—the CMG hardware that moves the spacecraft—are being manufactured by an Ithaca firm, Ithaco, just outside the Cornell campus.
“The fact that Ithaco is building these high-agility actuators is a big deal,” Peck said. “This is their first entry into this market. It’s a multimillion dollar a year market, so Violet is also complementing the local business environment with commercial and research applications.”
Several former students now work at Ithaco, Peck said.
With CUSat heading for the launch pad and Violet’s strong showing, Peck said it’s an exciting time for Cornell students and faculty, but also for the advancement of the aerospace industry.