NASA said Tuesday it will aim to launch the space shuttle Discovery February 24, after engineers found a way to shore up cracks on its external fuel tank that have delayed its final liftoff.

"We think we can support a launch date for the 24th of February," said Mike Suffredini, International Space Station Program manager.

NASA engineers have been working since November to figure out why cracks were emerging on the 22-foot-long U-shaped aluminum brackets, called stringers, on the shuttle's external fuel tank.

According to shuttle program manager John Shannon, engineers performed exhaustive tests and found that the complex problem was not solely a result of material quality or flaws that took root during assembly.

Shannon described the dilemma as "low risk" but at the same time, "hard to quantify."

In the end, engineers agreed that installing small metal strips, called radius blocks, on to the stringers would reinforce their strength.

"It is very hard to tell where your assembly stresses are, you can't really tell that by X-ray, so what we decided to was we could get rid of the whole discussion by putting in these things called radius blocks," Shannon said.