18
$\begingroup$

An EVA carries the risk that objects and people may become detached from the ship/structure and drift away from it. In the case of objects they might become a hazard or their loss might be a problem, but in the case of people it could be fatal.

I'm aware of NASA's EMU. For the purposes of this question it would have to be broken or out of propellant. Emergency devices that are not used in the normal course of an EVA are relevant though.

Has any space agency made plans for dealing with such an event?

Improve this question
$\endgroup$
5
  • 5
    $\begingroup$ There's always the space harpoon... $\endgroup$
    – user20636
    Aug 20, 2019 at 13:30
  • 10
    $\begingroup$ Re For the purposes of this question it would have to be broken or out of propellant. That's at least four failures deep. An astronaut becoming detached during an EVA in and of itself is at least two failures deep. And now you have an additional two failures on top of that. NASA doesn't and can not plan for that many bad things happening in a row. $\endgroup$
    – David Hammen
    Aug 20, 2019 at 14:32
  • 1
    $\begingroup$ The proedure is to sing a song from Frozen $\endgroup$
    – Strawberry
    Aug 21, 2019 at 9:21
  • $\begingroup$ I thought the standard procedure is to use a fire extinguisher ;-). $\endgroup$
    – Peter - Reinstate Monica
    Aug 21, 2019 at 10:56
  • $\begingroup$ As a desperate last resort, the astronaut could throw away everything not immediately essential to life support, in the opposite direction of the ship/structure, as hard as they can. These objects would push them back as per Newton's Third Law. Accuracy is very hard even if the force is strong enough. It's not impossible to work. $\endgroup$
    – Emilio M Bumachar
    Aug 21, 2019 at 12:16

1 Answer 1

Reset to default
31
$\begingroup$

A nitrogen cold jet thruster system called SAFER (Simplified Aid For EVA Rescue) is part of the US EVA suit ensemble. If a crewperson gets loose they can fly back using SAFER.

enter image description here

(Image source)

SAFER is not used in the normal course of an EVA. There is no other propulsive system on a US EVA suit.

SAFER was deemed necessary for the ISS era because either the Shuttle would not be present at the ISS during the EVA, or even if present, would take considerable time to undock and prepare to chase down the free-floating crewperson.

This photograph shows SAFER being tested for the first time on shuttle mission STS-64.

enter image description here

(Image source)

The system is flown by the use of a single hand controller instead of the usual one translational / one rotational hand controller scheme. The user selects between rotational and translational modes via a switch on the hand controller module. However, the controller has four degrees of freedom in either mode, with pitch commands being available in translational mode, and X translation being available in rotational mode. An attitude hold mode is available to automatically stop undesired rotations.

enter image description here

(Image source)

Procedures for the use of SAFER are found in the ISS EVA Checklist.

enter image description here

Acronymology

  • EV ExtraVehicular
  • GCA Ground Controlled Approach
  • HCM Hand Controller Module
  • IV IntraVehicular
  • WVS Wireless Vision System

Additional detailed information about the SAFER system is available here.

Improve this answer
$\endgroup$
9
  • 2
    $\begingroup$ If no gas flow / BRN TRSRS $\endgroup$
    – Richard
    Aug 20, 2019 at 20:43
  • 1
    $\begingroup$ "SAFER was deemed necessary for the ISS era because either the Shuttle would not be present at the ISS during the EVA, or even if present, would take considerable time to undock and prepare to chase down the free-floating crewperson." - so I guess the standard procedure in the "normal" situation is to chase them down with a soyuz? Is it even capable of being used for that? $\endgroup$
    – Nathan Cooper
    Aug 21, 2019 at 10:09
  • 3
    $\begingroup$ @NathanCooper what? The standard procedure is self rescue with SAFER. $\endgroup$
    – Organic Marble
    Aug 21, 2019 at 10:29
  • 1
    $\begingroup$ @Cris that's a troubleshooting step. If gas is not flowing, check that the supply valve is open. $\endgroup$
    – Organic Marble
    Aug 21, 2019 at 10:31
  • 3
    $\begingroup$ @PeterSchneider before the ISS era the shuttle would fly after a loose crewperson. I haven't the foggiest idea about the Russian's plans. $\endgroup$
    – Organic Marble
    Aug 21, 2019 at 11:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.