Shuttle's Launch May Be Delayed.

[Guest Guest]

April 29, 2005

 

Shuttle's launch may be delayed

 

Preventing possible break-off of ice could postpone blast-off of Discovery 2 months.

 

The Orlando Sentinel

 

CAPE CANAVERAL, Fla. -- NASA managers are expected to announce today whether they will delay the space shuttle's return to flight by two months to reduce the risk of ice debris breaking off the external fuel tank during launch.

 

Their decision would follow meetings Tuesday and Wednesday at the Johnson Space Center in Houston, during which an 11-member board of senior shuttle managers reviewed debris issues and the rationale for Discovery's planned May 22 liftoff.

 

According to NASA sources, officials are considering a postponement because of an ongoing concern about possible ice buildup on a liquid oxygen propellant line that runs from the tank's midsection to its base.

 

If a decision to delay is made, engineers would roll Discovery back from the launch pad to Kennedy Space Center's Vehicle Assembly Building. There, a heater would be added to a joint near the top of the propellant line to prevent ice formation.

 

A senior NASA shuttle manager said it was unlikely the change could be made in time to have Discovery ready for its upcoming launch window, which extends until June 3. Instead, the shuttle's return to flight would be targeted for the next window, which will open July 13 and close July 31.

 

For months, the shuttle program has been assessing the risk posed by debris to prevent a recurrence of the 2003 Columbia accident. During Columbia's launch, a suitcase-sized chunk of foam insulation broke off the tank and smashed a hole in the leading edge of Columbia's left wing. The breach led to the shuttle's breakup over Texas as it entered Earth's atmosphere, killing all seven astronauts.

 

NASA's focus in recent weeks has been more on ice debris than foam.

 

The 15-story tank is filled with more than a half-million pounds of liquid oxygen and liquid hydrogen fuel. The propellants must be chilled to hundreds of degrees below zero to maintain their liquid state. As a result, ice sometimes forms on parts of the tank's exterior and can break off during launch, becoming a potentially damaging projectile.

 

The propellant-line issue was one of the last debris scenarios out of more than 170 potential threats yet to be cleared by NASA managers.

 

Seventy feet long and 17 inches wide, the line carries liquid oxygen from the top of the tank to the shuttle's main engines.