NASA to set Discovery's launch date today

This morning at Kennedy Space Center, NASA executives have begun a flight readiness review expected to set an April 5 launch date for Discovery.

The shuttle and seven astronauts plan to fly a 13-day mission to the International Space Station -- one of four remaining flights -- to haul up tons of supplies, equipment and science experiments.

Three spacewalks are planned, primarily to replace an new ammonia tank critical to the station's cooling system. Check out a NASA summary of the 131st shuttle mission here.

You can follow NASA tweets updating the readiness review's progress here.

A press conference will follow the review, featuring Bill Gerstenmaier, associate administrator for Space Operations; John Shannon, Space Shuttle Program manager; and Pete Nickolenko, STS-131 launch director.

You can watch it live here by clicking on the NASA TV box at right.

Today's review will need to clear at least two special issues: a problem with a helium valve in Discovery's right, rear engine pod and a review of ceramic inserts used between tiles on certain sections of the orbiter.

The helium isolation valve failed during loading of steering jet propellants earlier this month, but tests last weekend showed regulators were working fine that control the flow of the gas used to pressurize the jets.

A ceramic insert near a window a crew cabin came loose during Endeavour's recent flight. Engineers also looked at areas around payload bay door hinges where the inserts are used. They want to be sure an insert would not strike a critical part of the orbiter if it tore away.

If the targeted launch time is confirmed today, Discovery would aim to blast off at 6:21 a.m. April 5, in the middle of a 10-minute window.

IMAGE: At launch pad 39A at Kennedy Space Center on March 5, the crew members of space shuttle Discovery's STS-131 mission pose for a group portrait in front of Discovery's external fuel tank. From left are mission specialists Dorothy Metcalf-Lindenburger and Stephanie Wilson; pilot James Dutton; commander Alan Poindexter; and mission specialists Naoko Yamazaki of the Japan Aerospace Exploration Agency, Rick Mastracchio and Clayton Anderson. The seven-member crew will deliver the multi-purpose logistics module Leonardo, filled with resupply stowage platforms and racks, to the International Space Station aboard Discovery. Credit: NASA/Kim Shiflett