ROME -- A problem with the Glory satellite's solar array system and continued engineering work to clear the Taurus launcher for flight are delaying the start of a $424 million NASA mission to investigate climate change.

Artist's concept of the Glory spacecraft in orbit. Credit: NASA

Managers tentatively reset Glory's launch for Feb. 23 to give teams more time to prepare the satellite and Taurus XL rocket, according to a NASA status report released Friday.

The Feb. 23 date is pending approval from the Air Force range.

The satellite was supposed to ship this month to the launch site at Vandenberg Air Force Base, Calif. Liftoff was previously scheduled for Nov. 22.

But ground testing uncovered a glitch in a mechanism that drives one of Glory's two solar panels, which generate electricity for the spacecraft and its two Earth observation instruments.

"It's a solar array drive we had an anomaly with and we're trying to correct," said Bryan Fafaul, Glory's project manager at the Goddard Space Flight Center in Maryland.

In an interview last week, Fafaul did not provide any more details of the problem or its solution. He did not respond to questions Friday.

Glory is currently in a factory at Orbital Sciences Corp. in Dulles, Va.

Orbital is also the mission's launch provider, and the company is wrapping up engineering reviews of the Taurus rocket's payload fairing, the culprit of a mishap in the booster's last mission in February 2009.

The shroud-like fairing did not jettison as planned during the 2009 flight, which carried the Orbiting Carbon Observatory, another NASA satellite linked to climate change research.

A NASA board of inquiry could not identify a single source of the anomaly, but officials noted four possible issues that could have caused the fairing separation failure.

NASA and Orbital are still completing their improvements to the rocket to address the potential causes of the mishap.

File photo of the Taurus rocket. Credit: Orbital Sciences

Glory's launch has been delayed more than a year since the Taurus mishap in early 2009.

Engineers used the extra time to improve a payload computer on the observatory and conduct more risk-reduction and environmental testing on the spacecraft, according to Fafaul.

"More time with the hardware is always a good thing," Fafaul said.

Fafaul said the Taurus return-to-flight reviews are also driving Glory's new launch date.

"The new launch date provides the necessary additional time required to complete preparations for the rocket and the spacecraft," NASA said in Friday's status report.

Orbital did not comment on the delay.

Glory's two instruments will measure Earth's energy budget and study the link between manmade and natural aersols and climate.

A solar irradiance monitor will quantify the solar energy entering the atmosphere to chart the sun's role in Earth's climate. The measurement is crucial for scientists identifying other sources of climate change.

"The most important thing that we have driving our climate is the sun," Fafaul said. "The first thing you need to know is did the sun change."

An aerosol polarimetry sensor will collect sunlight reflected off of atmospheric particles to determine their size, shape and properties, according to NASA.

Once it arrives in orbit, Glory will enter NASA's A-train formation of Earth observation satellites, flying a few minutes ahead of the Aura spacecraft at an altitude of 438 miles.