Sun shines on solar car team

MIT vehicle takes 3rd place in 2,500-mile race

Sarah H. Wright, News Office
August 5, 2005

The MIT Solar Electric Vehicle Team's car placed third in the North American Solar Challenge, completing the 2,500-mile course along U.S. Route 75 and Trans-Canada Highway 1 from Austin, Texas, to Alberta, Calgary, in just over 56 hours.

The world's longest solar car race, NASC 2005 began on July 17 and ended July 27. The University of Michigan's car, Momentum, took first place, making the arduous 10-day trip in just under 54 hours. The University of Minnesota's Borealis III placed second.

MIT's 375-pound, single-seat vehicle, called Tesseract, was one in a field of 20 sleek, low-slung solar cars that drove through city traffic, open highways and pounding Kansas rain using only the energy of the sun. (When the sun's not out, the cars run on batteries charged with solar energy.)

Tesseract's start was not sunny: MIT was in ninth place on the morning of July 17, but pulled into third place by day's end and held that position for much of the NASC event.

Other U.S. universities that competed included Missouri (fourth and eighth place), Western Michigan (sixth) and Stanford University (ninth). To qualify for NASC, each solar car had to prove it could drive 120 miles at a minimum speed of 25 mph.

The NASC course-known as a "rayce" among solar power enthusiasts-followed a straight line from south to north, with a sharp westward turn at Winnipeg, Manitoba. En route to the University of Calgary's Olympic Oval, the solar cars passed through checkpoints in Weatherford, Texas; Broken Arrow, Okla.; Topeka, Kan.; Omaha, Neb.; Sioux Falls, S.D.; Fargo, N.D.; Brandon, Manitoba; Regina, Saskatchewan; and Medicine Hat, Alberta.

Before the race, each NASC vehicle underwent a rigorous inspection process, known as scrutineering, in Austin, followed by a qualifying test at Texas World Speedway.

Despite its extraordinary shape, Tesseract is composed of ordinary parts, including 512 lithium-ion batteries, the same type found in most laptop computers. A 6-horsepower motor attached to the hub of the rear wheel provides power; there is no transmission.

The driver controls the car with center-mounted handlebars, much like a bicycle; the car uses four mountain-bike brakes connected to go-kart master cylinders and pedal to stop.

Tesseract's Batmobile-like sheen comes from its solar array-2,732 solar cells, the same cells used on NASA satellites-covering a Kevlar and epoxy resin body. A chromoly steel space frame holds Tesseract together. The suspension is a car-mountain bike hybrid.

The car's name has interdisciplinary significance. In geometry, a tesseract, or hypercube, is a 4-dimensional analog of a cube. In literature, science fiction author Madeleine L'Engle used "tesseract" both as a noun-a type of "wrinkle" in space and time-and as a verb, as in tessering, or travel in the fifth dimension, in her novel, "A Wrinkle in Time."

In September 2005, Tesseract will compete in the World Solar Challenge, traversing Australia from Darwin in the north to Adelaide in the south, a distance of about 1,860 miles.

The NASC 2005 contest was sponsored by the U.S. Department of Energy (DOE), Natural Resources Canada, DOE's National Renewable Energy Laboratory, TransAlta, University of Calgary, CSI Wireless, AMD and Manitoba Transportation and Government Services.