A student project to design, build, launch, and then communicate with orbiting satellites is ready for blast-off.

By Jay Wrolstad

IT’S certainly smaller than a breadbox, but it holds the hopes and dreams of scores of engineering students who have labored over its construction for the past three years.

A group of some two dozen of those students this winter ran the final battery of tests on ICE Cube,Cornell’s version of the CubeSat project run by Stanford University and California Polytechnic University with the express purpose of engaging students in the design, construction, and launch of “picosatellites” measuring just 10 centimeters on each side.

Michael Willhoff ’03 ECE, M.Eng. ’04, left, and Bryan Doyle ’05 ECE work inside the clean room on a power integration test with the custom power electronics board, solar panels, and rechargeable lithium-ion batteries.

Cornell’s ICE Cube (Ionospheric sCintillation Experiment CubeSat) satellites are packed tightly with technology, enabling them to examine a vast section of Earth’s atmosphere and the effects of so-called “space weather” on widely-used Global Positioning System (GPS) transmissions, collect data, and send the findings back to the Cornell campus some 400 kilometers distant.

“What’s nice about this project is that it’s so student-oriented,” says Mark Campbell, associate professor of mechanical and aerospace engineering, who is the ICE Cube faculty adviser. “They were responsible for every aspect of this, from structural design to subsystems creation to budgeting.”

Campbell compares the process to that of running a business, with participants handling all of the issues associated with creating a new product—including periodic setbacks—and eventually emerging from the lab as a close-knit team.

“There was a hierarchy, with graduate students and those who had experience with the project taking leadership positions in the subsystem groups,” he says, “then other students and individuals who got involved were plugged in where they were needed.”

Over the past three years, the composition of the ICE Cube team has changed continuously with some students graduating each spring and new ones added each fall. Still, the project is more or less on schedule, and everyone who played a part is anxiously awaiting (with fingers crossed) the July launch of the rocket that will carry ICE Cube into the outer reaches of the atmosphere.

Getting to the countdown wasn’t without its challenges. While construction of the aluminum cubes was completed early on at the Cornell physics machine shop, creating the internal components, such as circuit boards, software, and sensors, was an on-going effort. Particular attention was paid to the size and weight of each component that had to fit inside the small container.

Teams working on the power subsystem integrated an electronics board, solar cells, and a rechargeable camera-type lithium-ion battery. The CubeSat takes 90 minutes to circumnavigate Earth, Campbell explains, spending about 55 minutes in the sun and 35 minutes in the shade, and is programmed to alternately absorb solar energy or run off the battery. The small power plant generates 1.3 watts of useable on-board power and weighs just 180 grams.

The Cornell Amateur Radio Club was enlisted to assist in developing a communications system comprising an on-board radio system, a ground station receiver at Barton Hall, software for sending and receiving data, and antennas. Eight separate iterations of the radios were custom-built by students, a task that took three years.

The communications system is designed to store at least 1 megabyte of sample data and to download that much information daily using amateur radio frequencies, which required approval from the Federal Communications Commission and international authorities.

The final distance test was conducted without a hitch, using a ground station set up at a site at Ithaca College on the city’s south hill with a clear line of sight to Cornell’s Barton Hall a few miles away.

“Students have designed all of this equipment from the ground up,” says Mike Hammer, radio club adviser and director of data management for student services in the College of Engineering. The ground station at Barton will receive data collected in the ionosphere, with a communications window of opportunity of just three to twelve minutes during each orbit, he explains.

Those communications include verifying the temperature of the satellite, checking the status of on-board systems, and sending test results on the signal strength of the on-board GPS system.

Other systems for the diminutive spacecraft include attitude control to keep the antennas on the top and bottom pointed in proper directions to receive and transmit data and a gravity gradient boom to maintain its position.

To cope with temperatures in the ionosphere that typically vary between 70 degrees and minus-30 degrees Celsius, the satellite has eight sensors and a tiny battery heater to maintain the optimum comfort level. “We can use the data from this mission to determine what worked well in controlling temp variations, which will be of use to future projects,” Campbell says.

The brain of the cube is a main board that controls activation of individual components, samples internal systems data, and serves as both the central depository for scientific information and the agent for downloading those findings.

The finished product was put through its paces in a vacuum chamber on campus, enabling students to accurately replicate conditions found in space.

Terence Brauneis ’03 ME, M.Eng. ’04 (left), and Andrew Welch ’04 ME use the Cornell Thermal Vacuum test facility to simulate the vacuum environment and the temperature fluctuations of space. Development of the test facility was made possible by a gift from Edwin W. Hewitt ’54, B.M.E. ’55.

The nitty-gritty science gets underway after ICE Cube is deployed, with others of its type, from a rocket launched in Kazakhstan. The projectiles are loaded into a customized launcher, known as a P-POD (Poly-Picosatellite Orbital Deployer). When the rocket reaches the desired orbit, it ejects the P-POD, which holds up to three satellites. The CubeSats are then released to begin their missions.

Paul Kintner, professor of electrical and computer engineering, has worked closely with the ICE Cube team, seeking a closer look at scintillations in the ionosphere interfering with space-based global positioning systems used by the government as well as drivers, boaters, campers, hikers, outdoor sports enthusiasts, and others who want to pinpoint their location.

There is “weather” in space, just as there is in the lower atmosphere near Earth, caused by charged particles emanating from the sun. These disturbances, or scintillations, in the ionosphere can effectively shut down GPS signals or other satellite communications. ICE Cube puts a pair of GPS receivers into the ionosphere and takes measurements as it flies through the “storm.”

In certain positions on Earth, and at certain times of day, sunlight heats the ionosphere and causes severe turbulence. These disturbances have been measured from the ground, but not from where they originate.

“We can get a much better understanding of the effects of scintillation by taking measurements in space and eventually mapping the presence of these disturbances for future space missions,” Kintner says. To do that, he and his research team provided a GPS package including a ground-based receiver and sounding rocket-based receiver that has been used in previous space missions. For students, the challenge was to modify their software for ground-based and space-based measurements.

Because of the sensitive nature of GPS technology, the ICE Cube project needed government clearance to send the satellite overseas, and Kintner notes that the equipment on board is built to be tamper-proof.

The decision to hitch a ride on an Eastern European rocket came down to dollars and cents, Campbell explains. “This is the most cost-effective option, since our cost is about $40,000 for each launch, while in the U.S. it would probably be a couple of hundred thousand dollars,” he says. And that’s if you can find someone closer to home who is willing to relinquish precious cargo room for a student experiment that has the potential to jeopardize an expensive launch.

Nevertheless, a long-term goal of the CubeSat project is to conduct launches in the United States, and negotiations are underway with all major launch providers to assess that possibility.

ICE Cube’s launch, originally scheduled for October 2004, was pushed back to July 2005. Campbell says that ISC Kosmotras, the Kazakhstan-based firm providing the Dnepr rocket in which ICE Cube will reside, delayed the launch at the request of the customer providing the primary payload and footing most of the bill.

“That gave us more time to iron out the wrinkles through testing, although delays can cause problems because the optimal launch time available each year is limited,” Campbell says. Cornell’s two CubeSats are among a dozen to be deployed during the July launch.

Participants are grateful for the opportunity to explore the final frontier—an opportunity of immeasurable value according to their mentors.

“I got involved because I was looking for something different than my major. The project has made some of my coursework easier,” says Bryan Doyle, a junior studying electrical and computer engineering, who has toiled since fall 2003 on the ICE Cube power systems. “With this project I got exposure to new areas of engineering, like systems and mechanical engineering. It was a lot of work, but it was enjoyable,” he says.

Lucy Cohan, a senior majoring in mechanical engineering, was drawn to ICE Cube while working with Campbell on a different research effort and has contributed her knowledge as systems engineer since last summer, conducting tests, making structural changes, and putting the entire package together.

“I always wanted to do aerospace research. It’s gratifying to know that something I worked on will actually be launched into space,” she says. “This is important work in that we can detect errors in location technology.”

Norbert Huber ’05 ECE (left), Lucy Cohan ’05 ME, and Associate Professor Mark Campbell perform a final long distance communications test with one of the ICE Cube flight units.

Both students will help deliver the ICE Cube satellites to California, and then monitor its progress from campus. They’re confident the space probes will outlast the expected lifespan of three to six months.

“This gives students an experience that is not lecture-based, or problem-set driven,” Campbell says. “They now have one foot into the world of industry, and they have established camaraderie with a group of their peers.”

Kintner concurs, saying that the chance to put into practice the knowledge they gain from textbooks and lectures prompts students to address an array of research variables and develop solutions to challenges they wouldn’t typically face.

Steve Powell, a senior engineer on staff in the School of Electrical and Computer Engineering who works with Kintner and helped build the ICE Cube GPS receiver, cites practical experience in software development and equipment testing as benefits of the CubeSat program. “It’s valuable hands-on work that students might not otherwise get in school. It enables them to be more effective engineers when they graduate and makes them more attractive to potential employers.”

Radio club adviser Hammer says Cornell is better than most institutions in providing hands-on opportunities to students. ICE Cube is a prime example of that effort, he says.

“They have to make this work. When they are finished, it will be as if they have already been at their first job before they graduate,” he says. Hands-on work is done in electrical engineering design, testing, and verification, Hammer says, which contributed to one student landing a job at NASA’s Jet Propulsion Laboratory and another finding work with a defense contractor doing satellite research.

Initiated in 1999, the CubeSat project provides guidelines for the design of small satellites that can use a common deployer, with the ultimate objective being a low-cost space program with frequent launches. Program participants must design and construct a satellite conforming to the CubeSat standard created by California Polytechnic and Stanford. The standard describes the outer dimensions, offers recommended materials, highlights restrictions, and describes schedules pertaining to systems integration and launch. To date, some 40 colleges and high schools throughout the world have developed, or are working on, CubeSats.

Developers benefit from the sharing of information within the community, and resources are available to all by networking with others creating satellites and attending CubeSat workshops.

Beyond delivering small payloads into orbit, the project may well lead to groups of satellites flying in formation. Future mission concepts are expected to multiply exponentially, with educational institutions linking with private companies to offer services based on the little boxes, perhaps some as low-tech as carrying ashes into space as an alternative to burial.

“This has been a real challenge, but all of the hard work has paid off,” says Campbell. “We were able to bring on board new members, replacing a majority of students on the team each year. Fortunately, the advisers have remained the same, and we have maintained very good documentation to keep the project moving forward. I fully expect that ICE Cube will perform up to expectations, and we are excitedly looking forward to hearing our first signals from space!”

Jay Wrolstad is a freelance writer in Ithaca.