For Roy Shaham, weekend breaks from university life once meant flying a radio-controlled Cessna aircraft he had assembled from balsa wood. But now, Shaham spends his weekends designing a flying wing that might one day soar across Mars.
Shaham, 23, is one of 19 Cal State Northridge engineering students who received a $105,000 grant to design a lightweight, unmanned aircraft to scout Mars. The grant for the three-year project was awarded last year by the Universities Space Research Assn., a foundation sponsoring National Aeronautics and Space Administration-endorsed research at 43 universities throughout the country.
Established in 1984, the project was created to supplement NASA's space research division by encouraging ideas from university students. CSUN competed with 90 universities for a chance to participate in the program. CSUN was selected because of its well-balanced engineering school, said John Alred, a former NASA long-range planner who now manages the entire university-NASA program in Florida.
What are CSUN students designing? A tiny, solar-powered electric engine to propel five crafts that must function in Mars' carbon dioxide-rich atmosphere, Shaham said. The plane design, however, initially presented to NASA officials in April, is still in a non-working prototype phase. The students hope for completion by June.
"We've assembled all the numbers that prove that this thing will fly the way we've designed it," said Shaham, adding that the 2 horsepower engine will propel the crafts at about 150 m.p.h. "At least 80 percent of the power will come from the sun and the rest will come from a lithium battery."
The plane, with a wingspan of 30 feet, will weigh about 190 pounds.
Planning for the project "has proceeded beyond my expectations," said NASA aerospace engineer Robert Antoniewicz, who serves as mentor for the students. "We gave the students a wide latitude and few restraints. This is not like the narrow viewpoint that other research projects require. Sometimes getting a fresh viewpoint helps.
"Their work is a good starting point for NASA engineers to begin looking at a Mars mission."
The students' design will be considered by NASA for incorporation in an "autonomous flying rover," which could be sent with unmanned land rovers to Mars in the year 2000. The plane would scout for landing sites and take detailed photographs of the planet. NASA has projected a 1992 launch date for an orbiting Mars craft and envisions human explorers on the rocky surface before 2020, according to Alred.
Because the CSUN plane must be capable of flying 9,000 miles, the students' five proposed crafts would each have a range of 1,700 miles. The clone airplanes, carrying identical payloads, or instruments, would be launched successively from Mars after each had run its course.
"There's the advantage of sheer reliability with multiple crafts," said Dean Huebert, 24, a CSUN student and vehicle design manager for the project. "If one of the crafts finds something of real interest or something unexpected, the other planes' flight patterns can be changed."
Each craft is tightly packed in an "aeroshell," and would be deployed from a Titan missile launch, Huebert said.
"They would enter Mars' atmosphere in a nose-dive, build up some speed, pull out and then level out," Huebert said. "We've incorporated a collapsible boom that connects the tail to the wing. Once the aeroshell separates, the boom extends and the plane unfolds to its full length."
Huddled in the classroom corner, several students grapple with equations as they pass charts and statistics between them. Some munch on chips and drink from 7-Eleven cups, and others grab food out of Taco Bell bags while studying bar charts labeled "Aerodynamic Efficiency of Airfoils" and "Atmospheric Analysis."
"I varied the fuel weight fraction from point seven to point three on this chart," said Melanie Link, who works under Huebert in the systems area.
"The propulsion people are now thinking about using solar power, so we would have no fuel," Huebert said.
"How would that work with these stats?" asked Link, digging for more charts.
"It wouldn't," Huebert answered.
Such is the give-and-take of designing an aircraft--especially one that must function 33,000 feet above Mars' surface.
Huebert uses an IBM computer loaded with data from Viking landers to simulate Mars' thin atmosphere. "We took the atmospheric density, viscosity and temperature from different locations on Mars and plugged it into performance equations for conventional aircraft," he said. "You just plug in a configuration and the computer tells you, 'yes or no,' and what are the outcomes."
Each student, who spends about 15 hours every week on the design, reports to project managers who head mission support, vehicle design or propulsion groups. Design plans are periodically reviewed by Tim Fox, chairman of the mechanical engineering department of CSUN's School of Engineering and Computer Science. In June, the students will make a final presentation at NASA'S Lewis Research Center in Cleveland.
"At this point," Fox said, the students "have come a long way in meeting their goals and coming up with a good, solid configuration. I feel they've had a successful year."
Cathy Leary, CSUN project manager of the mission support, has recommended several scientific instruments to stow on board, including a gamma ray spectrometer capable of analyzing the atmosphere, an electromagnetic sounder capable of detecting water and ice to a depth of about a half-mile and a magnetometer, a mapping device adept at detecting magnetic fields and studying the planet's tectonic history.
Unfurling a map of Mars, Leary, 23, pointed to possible destinations. "The plane would fly to Olympus Mons here, the youngest and tallest of Martian volcanoes," said the CSUN student, who also works as an intern at Jet Propulsion Laboratory in Pasadena. "It's about 15 miles high. The plane could fly above the volcano and down alongside it; it would be an entry point."
Debate on the craft's design has shuffled between expandable boom wings, hinged wings, tandem wings, telescoping wings and even inflatable, rotary wings.
Different models were analyzed in the engineering department's wind tunnel, at speeds up to 150 m.p.h. "With a flying wing, weight is distributed throughout the craft. It makes it easier on the structure," Huebert said.
Although all 19 students involved in the design will graduate this year, the project continues for the next three years with other senior design students.
"We've laid the groundwork for next year's group," said project director Neil Rubin, 29. "They'll have the leisure to perfect the craft we've designed. And if they want to scrap it entirely, they can do that, too."
"All of us have a real passion for our work," Leary said. "It's not just, 'Oh, gee, I have to pass this class or get this lab report in.' Working on this design means I have to rely on my superiors, my group and my partners to complete the job successfully. It's given me insight about what the real world is about.
"And it'll look great on my resume."