MER Launch Reset For Fifth Time: Blame Booster

There's something wrong with the Boeing-made Delta II heavy launch vehicle that will lift America's second Mars rover mission toward the red planet. NASA is five for five in attempts to launch the MER package from the Kennedy Space Center. Every single attempt has been postponed for one reason or another. NASA next hopes to launch the rover "Opportunity" Monday night. In setting its sights on that launch window, the space agency passed up two chances to lift-off on Sunday. Officials say they want to get it right and the extra time couldn't hurt.

First, it was weather. Most recently, however, the cork that insulates the rocket's first stage has shown disturbing signs that it just doesn't want to stick to the rocket's skin. One of the delays last week occurred when engineers had to replace the cork in its entirety. Saturday night's launch was delayed for much the same reason. The cork is once again "debonding" in what NASA says are "limited areas." Scrubbing the Saturday night launch allows the flight team to pressurize the Delta's liquid oxygen tank in a sort of final test of the cork insulation.

It's Not Easier The Second Time Around

Compared to the relatively problem-free launch of its twin rover, "Spirit," Opportunity has been a technical headache for both NASA and Boeing. The band of cork around the launch vehicle is about two feet wide and a quarter-inch thick. Since Opportunity's is the first launch for this version of Delta II, engineers are taking extra time to check and re-check the insulation.

"[Even] though the first vehicle is behaving as well as it has, [Spirit and Opportunity] are in fact different vehicles and this a different launch opportunity and we should expect the unexpected and be prepared for it," said Peter Theisinger, head of the MER program.

Once it's off the ground, Opportunity will join the largest fleet of space vehicles ever to orbit Mars at one time. If all goes according to schedule, the Opportunity rover will join Spirit on the surface of Mars in January. Also orbiting the red planet are the EU's Mars Express vehicle with its Beagle II rover on board, Japan's Nozumi orbiter, NASA's Mars Global Surveyor and 2001 Mars Oddessy.

Opportunity and Spirit will search for ancient signs that water was once in abundance on Mars. Each will cover ground in a different Martian hemisphere, as scientists hope to maximize their chances of finding something that proves life might have once existed there. Britain's Beagle II rover will search specifically for tiny signs of life.

While the skies over Mars will be relatively crowded in about six months, there's no guarantee of safety in numbers. Of the past nine attempts to put landers on the Martian surface, only three have been functional. The rest gave up, burned out or augured in.

FMI: http://mars.jpl.nasa.gov/mer