Can the IDSS tunnel be cleared?

[DanClemmensen]

After docking, the IDSS port provides a 0.8 m diameter working passage. There is actually a 1 m tunnel, but the passageway is constricted by the capture petals and to a lesser extent by other components of the capture systems.

IDSS ports are used for visiting space craft, but they are also to be used to form permanent connections, e.g. between modules of a permanent station like Gateway. After a permanent docking, the capture systems will never be used again.

Question: can these capture components be removed after a permanent docking to allow the whole tunnel diameter to be used?

[Twark_Main]

Gateway will use NDS (an implementation of IDSS), and NDS has pedals that can be manually removed. However 0.8 m is when the pedals are already removed. With the pedals still in place, the passage has a clear diameter of 0.685 m.

https://ntrs.nasa.gov/citations/20110011626

Note, the SCS guide petals can be manually removed after docking to increase the passageway clearance. Section 3.11.1 provides more information on petal removal capability

3.11.1   IVA TRANSFER CORRIDOR AND AIDS

The Block 0 NDS design has SCS docking alignment petals that are fixed and cannot fold back into a stowage position for mated operations. With the SCS petals fixed in the deployed position, the NDS assembly provides an IVA transfer corridor diameter of ~27 inches as shown in Figure 3.3.2-1. The deployed petal clearance of ~27 inches (685 mm) has been evaluated as suitable for IVA Crew and Cargo Transfer Bag/Locker transfer. After the NDS is hard mated and pressurized, the SCS petals can be manually removed by an IVA crewmember to enlarge the transfer corridor diameter up to ~32 inches. However, the SCS alignment petals must be re-installed prior to vehicle undocking.

[DanClemmensen]

Gateway will use NDS (an implementation of IDSS), and NDS has pedals that can be manually removed. However 0.8 m is when the pedals are already removed. With the pedals still in place, the passage has a clear diameter of 0.685 m.

https://ntrs.nasa.gov/citations/20110011626

Note, the SCS guide petals can be manually removed after docking to increase the passageway clearance. Section 3.11.1 provides more information on petal removal capability

3.11.1   IVA TRANSFER CORRIDOR AND AIDS

The Block 0 NDS design has SCS docking alignment petals that are fixed and cannot fold back into a stowage position for mated operations. With the SCS petals fixed in the deployed position, the NDS assembly provides an IVA transfer corridor diameter of ~27 inches as shown in Figure 3.3.2-1. The deployed petal clearance of ~27 inches (685 mm) has been evaluated as suitable for IVA Crew and Cargo Transfer Bag/Locker transfer. After the NDS is hard mated and pressurized, the SCS petals can be manually removed by an IVA crewmember to enlarge the transfer corridor diameter up to ~32 inches. However, the SCS alignment petals must be re-installed prior to vehicle undocking.

This is puzzling. the IDSS specification calls for the transfer corridor to be 800 mm, and the diagram show this to be measured as a circle has the petals outside of it. See FIGURE 3.2.2.1-1 on page 3-9:
      https://www.internationaldockingstandard.com/download/IDSS_IDD_Revision_D_043015.pdf

[DanClemmensen]

Do the petals need to be there for undocking, or just need to be reinstalled for the next docking?
 Thing of emergency evacuation requirements.

I think there is a multi-part answer. I originally asked about inter-module connections at Gateway, where undocking will not occur except during major reconfigurations. In an emergency evac, crew evacualted in the spacecraft, not in station modules.

I do not know if the petals are needed for undocking.