ISS Spacewalk timeline

by Chris Bergin

The International Space Station (ISS) crew, consisting of Russian commander Pavel Vinogradov and NASA science officer Jeffrey Williams, are in the final stages of preparing for their 5 hours 41 minute spacewalk, set for Thursday. has acquired the full run down of activities that will be carried out on the 65th spacewalk at the orbiting outpost.

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Ready to depart from the Pirs airlock on the Russian segment of the ISS at 6:51pm EDT, the crew will head to the Zvezda Service Module to carry out the installation of a new hydrogen vent valve for the Elektron oxygen-generation system. The system has broken down several times over recent years.

The Elektron system is still not being used due to its problems – although it is hoped they will regain its oxygen replenishment on the 5th of June. Currently, the docked Progress craft (M-356/21P) is supplying oxygen for the ISS as required.

After taking imagery to confirm the installation has been successful, the crew will photograph the site of the KD2 engine cover obstruction, an area related to the aborted ISS reboost on the 19th of April.

Other tasks involve:
Removal of the platform with the third (last) Biorisk-MSN container on Pirs Docking Compartment. Removal of the BKDO Pressure Control and Exposure Monitor Sensor on Pirs Docking Compartment. Changing of the MBS (Mobile Base System) external TV camera on the U.S. segment

Removal of the Kromka No. 3 contamination ‘witness tablet’ on Zvezda Service Module. Tightening the slack of cables around the WAL3 (low gain) antenna for ATV on Zvezda Service Module.

In preparations for the EVA, the crew conducted a dry run for the spacewalk on Tuesday.

As published on NASASpaceflight’s L2 section on May 22, the Golf Experiment that was to be conducted on this spacewalk has been cancelled. Canadian company Element 21 Golf Company paid the Russians for the advertising opportunity of a golf ball being propelled off the side of the ISS.

However, the Russian’s have cancelled the opportunity indefinitely due to safety concerns raised by NASA, after they communicated concerns that the golf ball might actually collide with the ISS – which is orbiting at 17,500 mph.

Below is the full timeline preview.

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EVA-16 Preview for 6/1
(all times EDT):
  • ~5:06pm:  Close hatches between PkhO/FGB and PkhO/DC1
  • ~5:16pm:  Don Orlans, close backpacks
  • Check for leaks on suits and hatches
  • ~5:57pm:  Final O2 purge of Orlan systems
  • ~6:00pm:  Start  prebreathe (30 min, to denitrogenize body for prevention of decompression sickness)
  • ~6:30pm:  End prebreathe; depress DC1 to 15 mmHg
  • ~6:45pm:  Switch Orlans to autonomous power
  • ~6:51pm:  Open EV1 hatch
  • Collect hardware in DC-1
  • Egress DC-1 (ISS on SM thruster control)
  • Install “Yakor” foot restraint on Strela crane (ISS to CMG control)
  • Begin Elektron H2 Vent installation on SM
  • Take closeout photos of H2 Vent
  • Translate on Strela to WAL-2 antenna at SM aft end to photograph site of engine cover obstruction during aborted 4/19 reboost (SM thrusters inhibited);
  • Remove Kromka hardware.  Remove Biorisk container (off Strela)
  • Remove WAL-3 antenna cable slack.  Remove BKDO (Contamination Monitoring Unit)
  • Translate on Strela to DC-1, thence to FGB for MBS task (SM thrusters enabled, CMG control);
  • MCC-H Handover – begin MBS (Mobile Base System) Mast Camera swapout
  • TsUP-Moscow Handover – end MBS Camera swapout
  • Translate on Strela to DC-1
  • ~12:26am: Ingress DC-1.  Expected EVA duration = 5 hrs 41 min.

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