Mr Steven is the ocean-going vessel used by SpaceX in its attempts to catch re-entrant Falcon 9 fairings for possible reuse.

How is this ship controlled during fairing catch attempts?

  • Is she* manned or operated remotely (like the booster landing barges)? This redditor says manned, but with no citation.

  • Is she auto-piloted or is there a hot-shot pilot/controller at the wheel guiding her every movement to catch a fairing?

*It feels slightly odd referring to something called "Mr Steven" as "she", but that is the nautical convention.

  • 1
    $\begingroup$ I don't have any knowledge or evidence, but my money would be on the auto-pilot. The reaction time of a ship this size is much too slow for the ship to actively "catch" the fairing in any way. Any active movement needs to come from the fairing, not the ship. Ergo, the ship's job is to be as close to the position the fairing thinks it's in as possible, just like the drone ships. That's a job for GPS, a computer, and an auto-pilot. I don't see a reason for the ship to be unmanned, as long as nobody is standing on the deck when the fairing comes down, there is no significant danger. $\endgroup$ – Jörg W Mittag Jul 14 '18 at 11:33
  • $\begingroup$ Is there any ignitable or explosive remains of propellants within the fairing just like in landing boosters? Or toxic or carcinogenic hypergolic propellants? $\endgroup$ – Uwe Jul 14 '18 at 13:14
  • $\begingroup$ @Uwe After a descent of many tens of kilometers through the atmosphere, that seems highly implausible, the fairing halves being open shells. $\endgroup$ – Jan van Oort Aug 30 '19 at 10:23

According to this article on nasaspaceflight.com the vessel has a dynamic positioning system, which is a number of small thrusters that allow the boat to move in almost any direction. This is operated either with a computerized system, or manually using a joystick, though it is unclear which mode Ms. Tree (as Mr. Steven has since be re-named) uses.

I can find a number of scattered claims that the vessel operates automatically during the catch, but still has a crew on board, and the linked article says that due to being a ship instead of a barge, it is legally required to carry a crew.

In addition to this, the fairings have a parasail and thrusters, allowing themselves to be controlled as well.


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