The University of Colorado is primed for the approaching launch of its $90 million instrument package built in Boulder and destined for the International Space Station, where it will enhance the ability to monitor the Earth's climate.

The Total and Spectral Solar Irradiance Sensor, known as the TSIS-1, was designed and built at CU's Laboratory for Atmospheric and Space Science, for NASA's Goddard Space Flight Center in Greenbelt, Md. The $90 million contract value includes both the instrument suite and the associated mission ground system.

The TSIS-1 is slated to launch no earlier than Dec. 8 on board a commercial SpaceX Falcon 9 rocket in a Dragon capsule, from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

Once at the Space Station, the instrument will monitor the total amount of sunlight that hits Earth, as well as the way in which the light is distributed through the ultraviolet, visible and infrared wavelengths.

LASP Professor Peter Pilewskie, who is the project's lead mission scientist, said TSIS-1 will extend a 39-year record of measuring total solar radiation, which is the longest continuous climate record from space.

Satellite measurements of the sun from space have revealed that changes in its radiation over time, during both high and slow solar activity, vary by only about 0.1 percent, according to a new release. Scientists believe variations in solar output can't explain Earth's warming in recent years, but think that a longer data set might show greater swings in solar radiation.


"It's been said that trying to understand climate without understanding the sun is like trying to balance your checkbook without knowing your income. That's impossible," Pilewskie said during a Wednesday phone conference hosted by NASA.

Two LASP instruments make up the TSIS-1 — the Total Irradiance Monitor, which measures the total light emitted by the sun at all wavelengths, and the Spectral Irradiance Monitor, to measure how the sun's light is distributed by wavelength and absorbed by different parts of the planet's surface and atmosphere. Measurements of the sun's UV radiation are seen as key to understanding the state of the Earth's protective ozone layer.

Asked to describe the size of the instrument during Wednesday's news conference, Pilewskie said, "In its full extended position while tracking the sun, we like to say it's about the size of our mascot at the University of Colorado, which is a buffalo. It is fairly large. In stowed position, it is more compact."

The TSIS instrument suite, to be operated remotely from LASP's Space Technology Building at the CU Research Park, involved roughly 30 scientists and engineers at LASP at the project's peak, according to a university news release. LASP TSIS-1 Project Manager Brian Boyle said it also utilized about another 10 support staff in Colorado and another 10 outside the state. Approximately 15 to 20 CU undergraduate and graduate students have also been involved so far.

It is scheduled to run for at least five years.

Charlie Brennan: 303-473-1327, or