In discussions on previous posts it was debated whether ISS crew would need to "batten down the hatches" and confirm all objects were "lashed to the deck" before an orbital boost burn.

My thinking is that for the heavier objects the force necessary to restrain against the continuous air circulation (a mere breeze) would be much less than the force necessary to restrain against a 0.02 g acceleration

This is clearly seen in the two videos below, where as soon as the engines start, a several kg camera+lens and say a 65 kg astronaut immediately start accelerating towards the back of the bus station.

After 01:36 in the 2nd video there Demonstration of Acceleration Inside the International Space Station During a Reboost ISS Expedition 22 Commander Jeff Williams says:

OK here we are down in the Russian segment in the service module, and we don’t actually operate the reboost here on board, the ground programs it, and then the computers on board execute the reboost.

But we have insight into the parameters coming up, and it looks like we’re programmed to do a 2.7 m/s increase in our delta-v. When the engines fire, we will experience a small acceleration, not a whole lot, but it will be 0.0185 m/s^2, and I’m going to try to demonstrate that at the time of ignition, and during the burn.

Question: Are there standard procedures for securing the ISS before an orbital boost burn, and do they include checking that at least large objects are "strapped down", or does the fact that they haven't blown away indicate that there's nothing to worry about?

above: from ISS location identification; estimate size and direction of astronaut acceleration puzzler

below: from Can the ISS boost maneuver engine be heard by the astronauts on board?


2 Answers 2


Yes, there are several ISS Flight Rules and Payload Regulations requiring certain configurations during a reboost or other dynamic events.

  • Racks utilizing PaRIS (Passive Rack Isolation System) must have 3 of 4 Alignment Guides installed. (Here's a reference to the guides being installed prior to a dynamic event.)
  • External payloads with sensitive gimbals may need to a command window to stow and safe their payload prior to being subject to the dynamic loads of a reboost.
  • A crew activity must be scheduled to close the Cupola shutters to prevent contamination from thruster exhaust.
  • A ground command window must be scheduled to close the Lab WORF shutter for the same reason.
  • External payloads with sensitive science instruments require command windows to close their shutters.

Source: I was a POIC OC (Operations Controller) responsible for ensuring these activities happened before the POD (Payload Operations Director) gave a GO for reboost.


At least when the reboosts were done using the shuttle, there was no procedural call out to secure anything.

This answer steps through the procedures and includes links to the full text of both shuttle and ISS procedures.

How was the Space Shuttle Orbiter used for ISS Reboost?

  • 1
    $\begingroup$ Having the shuttle docked to the ISS is an unusual state, probably (presumably) there was a thorough check of the station including making sure things were secured before the shuttle docked. So there may not have been a scheduled repeat of that when the boost was scheduled. $\endgroup$
    – uhoh
    Apr 18, 2021 at 14:04
  • 3
    $\begingroup$ "probably (presumably) there was a thorough check of the station including making sure things were secured before the shuttle docked. " says who? Things are always secured except when they are actively being used. If there was a time consuming "thorough check" it would be in the flight plan. $\endgroup$ Apr 18, 2021 at 14:06
  • 1
    $\begingroup$ It was I who probably, and I presumed it. I reserve the right to be wrong and I'm always happy to be so! It's just that that scenario wasn't yet covered in the answer, so I brought it up. $\endgroup$
    – uhoh
    Apr 18, 2021 at 14:11
  • $\begingroup$ @OrganicMarble: and if someone forgot to resecure something after using it? $\endgroup$
    – Vikki
    Apr 18, 2021 at 19:41
  • 1
    $\begingroup$ @Vikki-formerlySean it would end up in the air filter. $\endgroup$ Apr 18, 2021 at 19:47

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