The arrival of Doug, the newest addition to the SpaceX recovery fleet, indicates further consolidation of the company’s rocket recovery operations. Although the launch cadence has slowed as SpaceX prepares the next generation of Starlink satellites, the fleet has been busy working on its next generation of recovery vessels to support what will hopefully be a busy last quarter of 2021.
In March 2021, it was clear that SpaceX had given up on trying to catch fairing halves. The vents on the fairings were moved to further support scoop-from-water recoveries after it was determined that a scooped half was not only just as likely to be reused but also carried less risk to recover.
Recovery ships GO Searcher and GO Navigator, as well as contract ships Shelia Bordelon and Hos Briarwood, filled the fairing recovery gap after February 2021 when GO Ms. Tree and GO Ms. Chief were released from their SpaceX contract.
A permanent replacement for the fairing catchers was needed. The primary role of GO Searcher and Navigator is Dragon recovery. Although they are designed to also haul fairing halves when necessary, their conflicting schedules meant SpaceX had to source new ships on temporary contracts to fill the gap when they were busy.
Having the two Dragon ships switching back and forth between different operations was also inefficient, and contracting temporary ships was likely very expensive. As a result, it became clear that a long-term solution was required, which also gave SpaceX an opportunity to optimize the operations of the wider fleet.
According to tracking data, SpaceX started conversion work on Bob and Doug in May 2020, transforming the ships from standard platform supply vessels – a kind of mini cargo ship that serves offshore platforms – into a SpaceX recovery ship. The ships were formerly named Ella G and Ingrid respectively.
These 280 feet-long ships were both modified to an identical design at an Edison Chouest shipyard in Louisiana. For comparison, the former fairing catcher ships were 205 feet long.
A raised platform covers around half of the deck area, which will possibly be used to store recovered fairing halves. Below that deck, a large winch has been installed, designed to pull in the chain from SpaceX drone ships so that the ship can tow them. In addition, a roller has been added to the stern of the ship, allowing the towing cable to smoothly run up onto the vessel.
Another obvious upgrade is the addition of a large crane. Its lifting capacity is difficult to estimate, but when fully unfolded, the boom can be roughly estimated to have a reach of around 45 meters. SpaceX workers will use the crane to lift fairing halves from the water after they splash down under parafoil control.
This design may have been influenced by SpaceX’s past experience with a contracted vessel named Shelia Bordelon that SpaceX used between March and May 2021. This ship had a smaller but similar crane that was highly successful at lifting fairing halves from the water and, upon return, onto trucks that would take them back for refurbishment. Before these cranes, fairing halves were lifted onto Ms. Tree and Ms. Chief using a net scooping system.
Earlier this morning, Shelia Bordelon returned to Florida with two intact fairing halves from the last Starlink mission.
— Gav Cornwell 🚢🚀 (@SpaceOffshore) May 1, 2021
Finally, both ships received a fresh coat of paint and some SpaceX branding. Additional communication dishes can be seen, including at least one Starlink dish. These two new ships represent a significant optimization of SpaceX recovery operations. By combining the roles of fairing recovery, drone ship towing, and drone ship support into a single vessel, SpaceX can reduce the number of support vessels required: down from a peak of five ships in January 2021 to just two going forward. This likely represents cost savings and reduces the number of workers who have to go offshore each mission, which in turn reduces risk.
How might this work and what does this mean for the future of the remaining support ships like veteran support ship GO Quest and drone ship tug Finn Falgout? There is potential that, as ASDS operations evolve, we may be saying goodbye to operations as we currently know them.
What we know so far from observing sea trials is that the voyage to and from the landing zone will not be entirely autonomous. Departure and arrival into Port Canaveral required tug assistance and a maritime pilot on the main tug. This is to protect port assets should the barge break tow or move out of control. It appears they also need to be about 12 miles offshore, past the gulf stream, before the ASDS begins autonomous operation.
The multi-purpose vessel could tow the drone ship out of Port Canaveral to 12 miles offshore and then shadow the drone ship as it runs autonomously to the landing zone. Technicians would then do final checks and ensure the deck was clear before moving to the fairing recovery zone.
After the fairing is recovered, they need to meet up with the safed booster, deploy Octagrabber, and shadow the ASDS all the way back to the 12-mile offshore mark, hook up, and enter Port Canaveral. What is unknown is the practicality of being fully autonomous for the journey to-and-from the landing zone. This would require more diesel to fuel the four large dynamic thrusters. Time will tell if SpaceX will choose to tow the drone ships for the journey to the landing zone.
In late 2019, the United States Coast Guard granted SpaceX permission to use its own private automatic identification system (AIS) aids to navigation (ATON) to mark the temporary exclusion areas during launches from Cape Canaveral. These safety zones are established from Cape Canaveral to be broadcast into the Atlantic Ocean. This was the first official Coast Guard approval for a dynamic restricted area.
Autonomous vessels are still new territory with the Coast Guard. In August 2020, they issued a request for information seeking the industry views on 16 questions on how autonomous commercial vessel technologies will affect US-flagged commercial vessels, as well as to evaluate potential barriers to developing autonomous vessels. As with ATON approvals, the USCG is working closely with SpaceX on ASDS operations.
The software to operate a vessel such as an ASDS is complex. Engineering systems need to converse with navigations and collision avoidance systems, and these systems all need to be secure from cyber-attacks. The unknown is how much of the vessel’s collision avoidance capability is AI and how much remains human-guided. The use of Coast Guard-approved ATON could generate a hazard zone during times of autonomous guidance at the landing zone, but is that practical for a full voyage?
Although questions remain about full autonomy, it is clear with the arrival of Doug and A Shortfall of Gravitas that the recovery fleet will continue to evolve. Upgrades continue on Just Read the Instructions in Florida, as well as Of Course I Still Love You, which has been relocated to California to support West Coast operations. Each mission going forward will offer clues on the progress of full drone ship autonomy.