Status Report

ISS Program Office Briefing: “Options for Increased ISS Crew Size”

By SpaceRef Editor

April 13, 2002

Filed under International Space Station, Johnson Space Center, US

Options for Increased ISS Crew Size

CB/Wendy Lawrence, DA/Dennis Webb, DT/Pete Beauregard
April 9, 2002

Issue Needing Management Direction: Budget assumptions for larger crews (Options 2-4)

Prior POP planning horizon did not include larger crews

– Cost has not been assessed and implementation is not consistent with prior assumptions

Expedition crew plan depends significantly on:

– Rotation mechanism (Shuttle versus Soyuz)

– Crew Role and Task assignments

– How many of the 6/7 crew need backup crewmembers

OM suggests that 3 of the 6/7 crewmembers will be Russians rotated on Soyuz, remainder rotating on Shuttle

CB and MOD training have assessed role and task concept for larger crew and identified issues.

Goal of additional crewmembers is to increase utilization return

– Rotation options vary in benefit to utilization hours

Increment crewmembers will rotate in segments

– Logistics and increment requirement process need to be assessed

Recommendation: OM lead OC, OZ, CB, and MOD in defining minimum cost integrated crew rotation concept for larger crews.

Overview of Large Crew Scenario

3 Russians (or Russian sponsored crewmembers) rotate on Soyuz

– Do all Russian Segment core ops, including EVA

– Russian assignment to US or other IP core and utilization tasks subject to negotiation

– If no CRV, separate taxi crews twice a year for second Soyuz

3 or 4 Americans and Other IP rotate on Shuttle

– Do most US Core and all USOS EVA/Robotic

– Do most US and other IP Utilization

Soyuz and Shuttle rotatees are changed out asynchronously

– 6 month stays with a part of crew changed out more frequently

– Crews are less integrated – Structure forces some segmented ops

CDR Handover between Russian and US not straightforward

Each CDR will have 8-11 crewmembers over his or her increment
not counting Taxi crews

Most crewmembers serve under two different CDRs

Difficult to train all crewmembers together who will serve together

7-Person Crew Issues

Cannot rotate all 4 non-Soyuz rotatees on a single shuttle flight

– Shuttle recumbent seat limitation

– Need to rotate in groups of 2 or 3

Options

– Pairs: Rotate 2 crewmembers each of 4 shuttle flights/year

– Scientist: Rotate 3 crewmembers twice a year and the 4th member (“scientist”) on each remaining shuttle flight

Without further guidance, MOD will assume:

6 crewmembers of the larger crews will get full systems training

– 3 are Russians rotating on Soyuz with an emphasis on Russian segment and support to Russian EVA

– 3 are US and non-Russian IPs will rotate as a group on shuttle with emphasis on US and non-Russian IP systems, including US EVA and Robotics

US and non Russian IP crew-members will receive training on US and non-Russian utilization

With CRV, 7th crewmember will be a dedicated utilization person who will rotate on shuttle flights not rotating the other 3 (“Scientist Option”)

All crewmembers will have backups

Forward work

Assumptions needed to refine training cost and improve utilization:

– How many US/CSA/ESA/NASDA Core and Utilization tasks and hours should be assumed by the Soyuz-rotated crew?

– For 7-person crew, which rotation scheme maximizes utilization?

– Can we omit backups for some crewmembers?

– Does a resolution of the CDR issue bring any new training requirements?

Determine net utilization crew hour capability for 6/7 crew

Potential other Cost-bearing impacts: