|
In 1998 the solid rocket booster recovery
ships took on a new service for NASA. Space Flight Operations contractor
United Space Alliance streamlined efforts for the Space Shuttle program by
taking over the towing of the Shuttle’s external tanks from Louisiana to
Florida using the Liberty Star and the Freedom Star. The new service makes
better use of the ships’ downtime between Shuttle launches.
The voyage begins near New Orleans at the
Michoud Space Systems Assembly Facility where the external tanks are
manufactured. Five days later, the ship and tank arrive at Port Canaveral
where a conventional tugboat takes over for the tank’s transit upriver
to the KSC Launch Complex 39 turn basin.
To withstand the towing burden, the
recovery ships had to undergo deck-strengthening enhancements. The stern
was strengthened at critical points, new bulwark fairings were added, and
an H-bitt was installed through which cabling is threaded to keep it
centered during towing operations. Also installed was a hydraulic towing
winch, referred to as a double-drum waterfall winch, holding 2,000 feet or
more of wire rope on each drum. One drum supports booster retrievals while
the other is devoted to external tank towing.
The recovery ship Freedom Star was the
first to be refitted for the towing and made its inaugural voyage on June
16. The second recovery ship, Liberty Star, was refitted shortly after.
|
