Just Read the Instructions (JRTI) is an autonomous spaceport droneship (ASDS). JRTI is a modified barge outfitted with a large landing platform, station-keeping thrusters and other equipment to allow SpaceX to land boosters at sea on high-velocity missions that don’t carry enough fuel to allow for a return-to-launch-site landing.
Just Read the Instructions was originally based in California to support missions out of Vandenburg. The droneship was moved to Florida in late 2019 to support the large number of launches booked to launch out of Cape Canaveral in 2020.
Just Read the Instructions is the second SpaceX droneship to use the name. The original SpaceX droneship, used for 2 experimental landings on the east coast used the same name but was retired and replaced by Of Course I Still Love You. The name was then given to the new droneship destined for the west coast.
JRTI was built in a Louisiana shipyard, alongside the east coast droneship Of Course I Still Love You. To reach its new home in Los Angeles the ship had to pass through the Panama Canal. The droneship was too wide to fit through so the extra wing extensions, designed to provide a larger landing pad, had to be placed on deck to be installed on arrival in LA.
Just Read the Instructions is out-fitted in a similar fashion to Of Course I Still Love You. Four azimuth thruster engines give the droneship the capability to maintain position at sea to within 3 metres using GPS. Cameras and sensors record the landings for analysis and 2 antennas up-link this data to a satellite and allow for communication with the incoming booster. Data up-link often cuts out at the moment of landing because heavy vibrations from the landing shake the antennas out of their lock with the satellite. This video explains more.
SpaceX droneships are not designed to autonomously move themselves over long distances. Instead, a tugboat is used to tow the droneship to the target position offshore in the Atlantic Ocean. The exact position of the droneship is dependant on mission requirements.
JRTI and the tugboat will leave Port Canaveral up to 7 days in advance of the launch date, with other accompanying support ships leaving later. After traveling to the landing zone the thrusters and other equipment will be engaged. Support vessels and the tugboat will then retreat to a safe distance to observe the landing. Just Read the Instructions is unmanned during all landings.
Once the landing is complete, Octagrabber will be deployed to secure the booster and SpaceX technicians will disengage the thrusters and prepare the droneship for the return journey. The tugboat will then tow JRTI back to Port Canaveral.
West Coast Departure and Upgrade
Just Read the Instructions was towed away from Los Angeles on August 1st 2019, heading for Morgan City, Louisiana. The droneship passed through the Panama Canal on August 18th. Because of the limited width of the Panama Canal locks, the wing extensions of Just Read the Instructions had to be cut off and placed on the deck for the transit.
Just Read the Instructions arrived at Morgan City on August 27th and was berthed at LAD Services Berwick. The ship spent about 4 months there whilst the side wings were reinstalled and the barge received a general refurbishment. JRTI was then towed to Port Canaveral, Florida – arriving on December 11th, 2019 with a large amount of equipment ready to be installed for a system upgrade.
Between January and May 2020, SpaceX technicians worked to significantly upgrade the droneship for service in the Atlantic Ocean. The old azimuth retractable thrusters were replaced with electrically driven fixed thrusters that remain permanently submerged underwater.
To power the new thrusters six diesel generators were installed alongside other supporting equipment. Just Read the Instructions also gained an Octagrabber robot, something it did not have during Pacific Ocean operations.
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