Photo courtesy NASA
Note: This week’s interesting ships are reposted and updated from gCaptain’s archives in commemoration of the last space shuttle launch today, July 8th, 2011.
When one thinks of a NASA ship, it’s generally not the seagoing type that pops into ones head. However, NASA does in fact have two vessels made for the high seas – MV Liberty Star and the MV Freedom Star – that assist with a shuttle launch. Both vessels are tasked as recovery ships for retrieving spent Solid Rocket Boosters (SRBs) that are used to power the shuttle’s ascent into space. After two minutes of flight, the boosters separate from the orbiter and external tank at an altitude of approximately 24 miles, descend under parachutes and land in the Atlantic Ocean where the MV Liberty Star and the MV Freedom Star are waiting to retrieve the reusable SRB’s.
It all begins about 24 hours before a shuttle launch, when the two ships set out to sea, manned by highly trained crews of professional merchant mariners and divers. During the operation, each ship retrieves one booster. Each ship has a permanently assigned crew of 10: a captain, two mates, four seamen, two marine engineers and a cook. In addition, eight divers accompany each crew to perform the delicate retrieval operation.
Here is an image taken from from the May 2008 STS-124 mission of an SRB splashing down into the ocean.
Once the boosters splash down into the ocean, the recovery ships spring into action:
First the pilot chutes and main parachutes are brought aboard. They’re followed by the drogue parachute and the 5,000-pound frustum that houses the chutes at the top of the booster. With those elements secured onboard, attention turns to the booster itself, as a team of eight divers boards two small boats. After installing a 1,500-pound apparatus called an “enhanced diver-operated plug” and air hose, the water is removed from the booster. The booster then rises in the water until it falls horizontally and floats on the surface, enabling the ship to tow it back to port behind the vessel.
Once recovered, the boosters are refurbished and reused in future shuttle launches, and the MV Liberty Star and the MV Freedom Star take on additional duties such as assist with diver training for NOAA and the Navy and additional utility uses. As to where they go now that the last space shuttle has launched? We’re not sure.
The Liberty Star and Freedom Star were specifically designed and constructed for this task. Built at Atlantic Marine Shipyard, Fort George Island, near Jacksonville, Fla., in 1980 and 1981, the ships are 53.6 meters (176 feet) in length, 14.3 meters (37 feet) in width and draw 3-4 meters (10-12 feet) of water.
A good article on the SRB retrieval mission has just been posted to the NASA website HERE.