Equipped with a new camera and spectrograph, the upgraded Hubble Space Telescope once again will allow Daniel Vanden Berk to gain some star power.

The assistant professor of physics at St. Vincent College in Unity, Westmoreland County, kept close track of NASA's dangerous Hubble repair mission, which ended successfully yesterday morning as the Space shuttle Atlantis landed at Edwards Air Force Base in California.

Dr. Vanden Berk has a stake in the mission's success.

His research proposal to use the Hubble in 2004 was canceled when its Space Telescope Imaging Spectrograph failed Aug. 3, 2004. Then on Jan. 27, 2007, its Advanced Camera for Surveys also failed. Both were important instruments for Dr. Vanden Berk's cosmic research.

Approval for him to use the newly installed Cosmic Origins Spectrograph on the Hubble is one of four he's received. NASA approves only about one in six research applications each year so "it's a very happy time" when one is accepted, he said.

Once instruments are tested, Dr. Vanden Berk will employ the spectrograph to identify the gases in the Andromeda Galaxy and determine how fast they're moving. Those calculations will be used to determine the galaxy's total mass, which in turn will show how much dark matter it contains.

Dark matter and dark energy are yet to be identified or understood forms of matter and energy. But they are necessary to explain the gravitational forces existing in the universe and the speed at which the universe is expanding.

"Andromeda is a good cosmic laboratory to study dark matter," Dr. Vanden Berk said. "We need a space telescope to see ultraviolet light, which you can't see from the ground. The Hubble Telescope is the only telescope available."

Along with University of Pittsburgh researchers David Turnshek and Sandhya Rao, among others, Dr. Vanden Berk will use the Hubble spectrograph to study light from quasars behind the Andromeda Galaxy. The spectra from different types of quasars already are known. The spectrograph divides light into its constituent colors, much like a prism, with resulting color patterns identifying the gases through which the light has traveled.

Dr. Vanden Berk will analyze the spectrum of light filtering through Andromeda's gases, much like a spotlight shining through fog, to determine what gases exist and their speed, which in turn will measure gravitational forces and total mass. Subtracting known visible mass of stars, gases and dust from the galaxy's total will pinpoint how much black matter the galaxy contains.

Results from Andromeda could provide clues to the quantity of dark matter our Milky Way Galaxy might contain.

During the 11-day mission, beginning May 11, astronauts aboard Atlantis made five space walks to repair the Hubble. The project extended the longevity of the telescope, first launched in 1990, until 2014. It has circled Earth more than 97,000 times and provided more than 4,000 astronomers with information about galaxies and stars invisible on Earth due to atmospheric obstructions.

NASA said the Hubble spotted objects that emitted light 13 billion years ago, which NASA's Dave Leckrone said means the telescope has taken us on "a voyage through the universe" almost to its beginnings an estimated 13.7 billion years ago.

Dr. Vanden Berk's focus is closer to home: the Andromeda Galaxy is only 2.9 million light years away from our solar system.

For 17 years, he worked on the Sloan Digital Sky Survey, which produced a three-dimensional map of the universe and created a huge database that's been used in 2,000 scientific studies. Google Sky also uses its photographs.

"One of the biggest results was confirmation that strengthened evidence for dark energy," Dr. Vanden Berk said. "Without dark energy, the universe would be expanding but slowing down. But the expansion is getting faster. That actually was a shock 10 years ago."

CERN's new Large Hadron Collider based in Switzerland will be used to study dark matter and dark energy. With no further repairs scheduled for the Hubble, NASA plans to launch the new James Webb Telescope in 2014.

Dr. Vanden Berk, whose specialty is spectroscopy, studies light spectra from quasars, which he describes as lighthouses in the distant universe. It's still unknown how galaxies form and change over time.

"I hope by September, we'll know how well the new equipment on the Hubble is working," he said.