BRIGHAM CITY, Utah -- A space shuttle solid rocket booster, anchored horizontally in the high desert of northern Utah, will be ignited for a two-minute firing Thursday that caps a test program dating back to 1977.

Booster maker Alliant Techsystems will conduct the test just before 12 noon Mountain Time (2 p.m. EST; 1900 GMT) at its facilities in Promontory.

Engineers have 43 design objectives for the full-scale shuttle rocket, which is instrumented with 258 channels of data.

It will be 52nd such test performed for NASA's space shuttle program. The first test was conducted on July 18, 1977, during the shuttle's early development.

With the shuttle program now winding down and only four missions left to launch into space this year, officials say Thursday's test will ensure those upcoming boosters fly safely.

The twin solid-fuel rockets provide 80 percent of the thrust needed to propel the space shuttle off the ground. A single shuttle solid rocket booster generates up to 3.3 million pounds of thrust during ascent, equivalent to 22 million horsepower.

Each motor is packed with 1.1 million pounds of propellant and burn about five tons of fuel per second. The rubber-like fuel resembling a pencil eraser is a blend of aluminum powder, ammonium perchlorate, HB polymer, iron oxide and an epoxy curing.

The pure white boosters are 149 feet long and 12 feet in diameter. They are comprised of 11 steel sections that are stacked together.

Known for their reusability, the motors parachute into the Atlantic Ocean during launch for retrieval and refurbishment. The booster being used in Thursday's test has casings flown previously on 38 shuttle missions.

Spaceflight Now will be covering Thursday's test live from the ATK test site. Check back for photos, high-definition video and a full story on the milestone event.