Weather balloon takes solar cell experiment toward sun

Jun 11, 2013

(Phys.org) —How do solar cells behave at high altitudes? Do they perform better the closer they get to the sun? Those simple questions propelled four undergraduate students from Northwestern University's McCormick School of Engineering and Applied Science into high gear.

A year later, the team, led by Mark Fischer, who will graduate in June with a B.S. in mechanical engineering, cheered as the payload that was sent 97,000 feet into the atmosphere on a parachuted back to Earth intact.

Fischer and fellow McCormick seniors Julian Minuzzo, Jingwei Lou and Sail Wu, who sent the solar cell experiment—with a video camera—up from an Indiana field May 23, were surprised by the answers to their simple questions.

When they reviewed the data and crunched the numbers, they found that the solar cell—a device that converts the energy of sunlight directly into electricity—did not, as expected, perform best at the highest altitudes. They assumed that closer proximity to the sun would mean more intense rays and better performance.

It turns out, the sweet spot for a high-altitude solar cell is between 50,000 and 60,000 feet above Earth's surface.

"Solar cells are more efficient as they get colder," Minuzzo said. "As altitude increases, the gets colder, but then you reach a point where it gets warmer again. The air is coldest between 50,000 and 60,000 feet."

This video is not supported by your browser at this time.

The findings could be important for future technologies like solar-powered aircraft and .

The project was a great learning experience for the students—not just about or weather balloons, but the value of careful preparation.

"There's this moment where you count down—3, 2, 1—and let the balloon go, and there's nothing you can do. It's out of your hands," Fischer said. "You it and cross your fingers and hope you did everything right."

The experiment traveled 40 miles in one hour and 56 minutes before returning to Earth—31 miles from the launch site—recording data and images during the entire trip.

Explore further: Obama salutes 45th anniversary of US astronauts' Moon landing

add to favorites email to friend print save as pdf

Related Stories

NASA's IRIS mission readies for a new challenge

May 22, 2013

(Phys.org) —The time draws near. NASA is getting ready to launch a new mission, a mission to observe a largely unexplored region of the solar atmosphere that powers its dynamic million-degree outer atmosphere and drives ...

NASA's STEREO detects a CME from the sun

May 17, 2013

On 5:24 a.m. EDT on May 17, 2013, the sun erupted with an Earth-directed coronal mass ejection or CME, a solar phenomenon that can send billions of tons of solar particles into space that can reach Earth ...

Students Launch Cockroaches and Cameras Into Space

Mar 12, 2009

(PhysOrg.com) -- A group of cockroaches recently took a ride on a high-altitude balloon launched into space by freshmen aerospace engineering students from the University of California, San Diego. The cockroaches ...

Solar plane aims for new world distance record

May 22, 2013

Solar Impulse, the first aircraft that can fly day and night fueled entirely by energy from the sun, embarked Wednesday on the second leg of its historic journey across the American continent.

NASA sees sun emit mid-level flare

May 03, 2013

(Phys.org) —The sun emitted a mid-level solar flare, peaking at 1:32 pm EDT on May 3, 2013. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere ...

Recommended for you

Heat testing the miniature Aausat 4 satellite

5 hours ago

The miniature Aausat satellite undergoes repeated temperature variations in a vacuum chamber, cooling the CubeSat to –10°C and heating it to +45°C for more than two weeks. This harsh baptism will make ...

New meteor shower "just a memory" of what once was there

5 hours ago

The weak display of last month's Camelopardalids meteor shower, the result of the close passage of comet 209P/LINEAR, may have disappointed backyard observers, but this never-before-seen shower now has scientists ...

New launch date set for ISS delivery vessel

22 hours ago

A robot ship will be launched from Kourou, French Guiana, after a five-day delay on July 29 to deliver provisions to the International Space Station, space transport firm Arianespace said Tuesday.

User comments : 0