Skip to main content /SPACE /SPACE

New orbiter to make X-ray flicks of sun

Artist's concept of HESSI
Artist's concept of HESSI  

(CNN) -- An $85 million satellite that will make movies of powerful solar flares roared into space Tuesday, following more than one year of launch delays.

The High Energy Solar Spectroscopic Imager, or HESSI, comes equipped with a new kind of vision that will create the first high-fidelity films of the most powerful explosions in the solar system, intense X-ray and gamma ray outbursts from the sun.

Such blasts can interfere with the electrical environment around the Earth, disrupting satellite communications, knocking out power grids and generating spectacular aurora displays.

"We are making color movies in X-rays," said project scientist Brian Dennis of NASA's Goddard Space Flight Center, likening the process to conventional movie-making, save for the fact that HESSI will observe the sun in a part of the light spectrum invisible to the naked eye.

NASA had hoped to deploy HESSI about 18 months ago during the peak of an 11-year cycle of solar activity. But a string of unrelated mishaps kept pushing back the mission.

The delays included everything from an automated test accident that shook the observatory too hard to a prolonged investigation involving the launch vehicle.

Last June, one such Pegasus rocket careened out of control during the launch of a prototype of NASA's X-43A, an experimental plane designed to attain speeds as high as Mach 10.

But everything went smoothly during the HESSI send off. Shortly before 4 p.m. EST, a Lockheed jetliner about 39,000 feet (12,000 meters) over the Florida coast dropped from its belly a Pegasus rocket, which streaked skyward on a nine-minute flight and carried HESSI to an orbital perch 373 miles (600 km) high.

"It looks like we had an excellent flight," said Omar Baez, HESSI flight engineer at NASA's Kennedy Space Center in Florida.

Fortuitous double peak

Despite the delays, project scientists remain optimistic about the timing of the launch, given that they think the sun has entered a second peak of activity and HESSI can still observe a high number of the most powerful solar flares.

Sun double peak. Courtesy: MDI/SOHO
Sun double peak. Courtesy: MDI/SOHO  

"We have been fortunate that the activity has stayed up. The sun has remained active and we are quite excited to get HESSI up," said Bob Lin of the University of California, Berkeley.

HESSI is expected to observe about 1,000 major flares during its two-year mission, which researchers hope NASA will extend at least six additional months.

The largest solar flares release the same energy as about one billion tons of TNT within seconds or minutes. In contrast, hydrogen bomb explosions are measured in megatons, or millions of tons.

The 645 pound (293 kg) probe will join a fleet of orbiters that observe the sun, including the Solar and Heliospheric Observatory (SOHO), the Geostationary Operational Environmental Satellite (GOES) and the Transitional Regional and Coronal Explorer (TRACE).

Another sun watcher, Ulysses, orbits the sun and travels over its poles from time to time.

In the past, catching gamma rays has proven difficult because they pass right through conventional lenses and mirrors. "The photons are smaller than the distance between atoms in the material," Dennis said.

To help lasso the elusive light particles, HESSI will spin once every four seconds as its imaging spectrometer observes the sun. "Fifteen rpms (revolutions per minute) is about as fast as we can go and still maintain control," he said.

-- CNN's Amanda Barnett and Richard Stenger contributed to this report.


Note: Pages will open in a new browser window
External sites are not endorsed by CNN Interactive.


Back to the top