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Chel Stromgren Strategic Analysis Team

January 14, 2009

Lunar Surface Systems Crew Time Analysis Overview

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Key Points

♦  Primary goal of this effort was to begin an integrated analysis of potential crew time restrictions on lunar scenarios

♦  Objective is not to “solve” for a crew time availability result but rather to explore crew time drivers, to evaluate sensitivities, and to identify potential crew time issues

♦  Historical ISS experience has taught us that it is difficult to carve out a significant amount of time for utilization, especially during build-up - smaller crew, assembly/outfitting tasks, infant mortality

♦  General LSS team feeling is that we must break that paradigm for LSS and ensure that there is a sufficient amount of time available for utilization right from the start

♦  Lunar specific challenges: •  Increased EVA rates •  Large fraction of time planned for SPR excursions •  Large number of “dynamic” elements - chassis, ATHLETE, SPR, ISRU, etc. •  Potential for large amount of unloading, movement, and site work •  No planned visiting crews to augment time

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Current Observations

♦  Given current outpost crew time assumptions and priorities: •  It is likely that the projected number of SPR Excursions in a typical 180-

day stay will be: -  4 Long Duration (14-days each) -  4 Short Duration (3-days each) -  68 total days in SPR

•  Current manifesting analysis assumes for a 180-day stay: -  4 Long Duration (14-days each) -  8 Short Duration (3-days each) -  80 total days in SPR

•  15% decrease in projected number of SPR Excursions from current scenarios

♦  Total fraction of surface time devoted to utilization (science) could be less than 20%

♦  Maximizing time on SPR excursion limits any utilization at the outpost

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Crew Time Model

♦  Crew time model is an integrated scenario-level analysis, incorporating scenario and architecture data for: •  Maintenance and repair estimates •  Offloading / Set-up task estimates •  EVA schedule •  Mobility schedule

♦  Model is derived from the VIPER ISS crew time model, modified to account for differences in ISS and LSS operations

♦  Maintenance/Repair and Offloading/Set-up estimates derived specifically for LSS architecture

♦  Utilization time is treated as the dependent variable

♦  NO time estimates included for additional potential outpost activities such as: •  Berming •  Moving of regolith for radiation protection •  Landing pad preparation •  Crew ISRU support •  Road construction

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Crew Time Liens ♦  Estimates for crew time Liens were derived from historical ISS crew time

distributions

♦  Liens are crew time usage not devoted to maintenance/repair or utilization

♦  Examined actual daily schedules for every ISS day from 2005 to 2007

♦  Developed statistical data and adjusted for differences between ISS and LSS

Task Type Average

Weekly ISS Time (Hours/

Day/Crew)

LSS Time Weekly

Estimate (Hours/Day/Crew)

% Change Notes

Routine Ops 3.0 3.0 Inspection 1.5 1.5 Conference / Tag-Ups 9.0 7.0 -22% Reduced tag-ups regarding in-lab science experiments Training 2.0 2.0 Work Prep 4.0 3.0 -25% Less in-lab science prep Traffic 1.5 0.0 -100% No docking / undocking of vehicles Medical 4.0 4.0 Public Relations 1.25 1.5 +20% Increased public interest Stowage / Inventory 2.0 1.0 -50% Application of RFID technology

. Exercise 16.0 10.0 -38% Reduced exercise requirement due to EVA rate Food Prep 3.25 2.0 -38% Simpler MRE style meals Meals 12.25 12.25 1.75 hour/crew/day Pre / Post Sleep 10.5 10.5 1.5 hour/crew/day Sleep 59.5 59.5 8.5 hour/crew/day Personal Comm. 1.5 1.5 R&R 20.0 20.0

Margin 0.75 0.75

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Historical Comparison of Time Distribution

♦  Compared working LSS crew time distribution to other analogs ♦  Dean Eppler provided time logs for his Antarctic ANSMET experience in

2002-2003 •  Averaged times for all regular working days •  Excluded “relocation” days where camp was struck-down and moved

♦  ISS Strategic Planning and Integration (SPI) team provided strategic planning values for future 6-crew ISS missions

♦  Aggregated historical ISS data from 2005-2007

D. Eppler Antarctic Data - Average Non-

Relocation Day (Hours/Day/Crew)

ISS Strategic Planning Values

(Hours/Day/Crew)

Observed ISS Values 2005-2007 (Hours/Day/Crew)

Working LSS Values (Hours/Day/

Crew)

Sleep/Pre/Post 9.6 10.2 10.0 10.0

Meal Prep/Meals 2.9 2.8 2.2 2.0

Personal/Down Time/Exercise 6.2 4.1 5.5 4.5

Logistics 0.3 0.4 0.5 0.1

Team Activities/Conference/Training 0.2 1.4 1.6 1.3

Work 4.8 5.0 4.3 6.1

Total 24.0 24.0 24.0 24.0

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Assumptions/Methodology ♦  No repair or maintenance performed while on SPR excursion - emergency fix only to get

back to outpost

♦  Model inputs prioritize allocation of time - priorities can be reset or balanced •  For the baseline analysis the following priorities are used:

1.  SPR EVA Time (up to 24 hour/week/crew limit) 2.  SPR Driving Time (up to 6.67 hours/day) 3.  SPR Excursion Days (up to manifesting assumptions) 4.  Outpost Utilization EVA Time (up to 24 hour/week/crew limit) 5.  Outpost Utilization IVA Time

♦  Certain tasks do not have to be performed while on excursion but must be made-up at a pro-rated rate once crew has returned to outpost: training, medical, personal comm., stowage/inventory, and R&R

•  Model attempts to achieve 24 hours/week of EVA and 6 hours of driving time per day while on excursion •  Remaining SPR time is used complete as much of liens as possible while on excursion •  No assignment of IVA science time in SPR

♦  No Utilization requirement at Outpost: •  For initial runs only minimal amount of EVAs, required to complete maintenance and logistics are completed

at outpost - no EVA time required for science •  No IVA science requirement at the outpost is assigned

♦  Aside from SPR excursions, there is NO consideration in the model that certain tasks may require continuous time blocks - all time may be efficiently used

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♦  Current manifesting of SPR Excursions is based on six-week centers (SAT team is running variations) •  1 Long (14-day excursions) •  2 Short (3-day excursions)

♦  Yields 80 days on excursion in a 180-day outpost stay (4 Long & 8 Short)

♦  Assume 2 SPRs and 4 crew per excursion

♦  24-hours per week max EVA rate •  On 3-day excursions it is possible to complete 24 hours/crew during 3-day excursion with

no additional EVAs for remainder of week

SPR Assumptions

Week 1 Week 2 Week 3 Week 4 Week 5 Week 6

Long Excursion (14-Day) Short Excursion

(3-Day)

Short Excursion

(3-Day)

Repeat

14-day 14-day 14-day 14-day

3-day 3-day 3-day 3-day

r&m r&m r&m r&m

Rest & Maintenance

(r&m)

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Maintenance & Repair Time Estimates

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Offloading/Set-Up/Outfitting Time Estimates

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Lunar Exploration Architecture Manifest Scenario 4.2.1 Initial Core Capability

FY19 FY20 FY21 FY22 FY23 FY24 FY25 FY26 …

MCT

SPR

SPR

Tri-ATHLETE x2

RPLM-2 & PSU Tri-

ATHLETE x2

RPLM-1& PSU

OPS Plant & Tools

OPS Plant & Tools

CMC

MPU

0 4 0 4 0 4 4 0 4 4 4 0 4 0 7 0 14 0 21 21 0 40 45 0 75 75

# - Crew Size # - Surface Duration

Test

Flig

ht

HLR

Core Hab & PSU

Rover

LCT

OSE

Beg

in s

erie

s of

3 M

issi

ons

per y

ear f

or o

ne y

ear

follo

wed

by

one

year

with

4 M

issi

ons.

Ser

ies

repe

ats

as n

eces

sary

to

supp

ort s

usta

ined

con

tinuo

us h

uman

pre

senc

e.

DPLM & PSU

DPLM & SSU

DPLM & SSU

DPLM & PSU

4 0 4 0 4 4 0 4 0 180 0 180 0 180 180 0 180 0 180

DPLM & SSU

4

Start of Continuous Human Presence

Notes: •  500 kg of payload (e.g., scientific research, commercial,

Education and Public Outreach (EPO), International Partners, etc.) is delivered for each mission

•  The 7 day missions have a rover and 250 kg of payload •  Payload, unpressurized goods, liquids, and gases are not shown •  Through FY30, there are 59 14-day and 130 3-day SPR

excursions

0 0

CDK

OSE

1

2 3

4

5

6

7

8

9

10

11

12

13 14

15

16

17

18

19

20

21

22

23

24

Human Lunar Return

Adv ECLSS

- Mission Number #

RA

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Results for a Typical 180-Day Increment

Outpost IVA Work

Time Liens (1472 hrs)

Outpost IVA

Maint. (767 hrs)

Sleep/PS (4480 hrs)

R&R/ Personal

(1424 hrs)

Food/Meals

(912 hrs)

Exercise (640 hrs)

Pro-Rated SPR Non-

Work Liens

(831 hrs)

Required Outpost

EVA (123 hrs)

IVA Util (104 hrs)

SPR Work Time Liens (854 hrs)

Sleep/PS (2720 hrs)

Food/Meals

(553 hrs)

SPR IVA/EVA Util

(1056 hrs)

Driving (1804 hrs)

17,280 hours

Outpost: 10,752 hours (112 Days)

SPR: 6,528 hours (68 Days)

♦  Outpost IVA requirements drive total required outpost days (not required EVAs)

♦  112 required outpost days do not allow currently manifested excursion schedule •  68 excursion days – 4 long and 4 short - are projected •  80 excursion days – 4 long and 8 short – are currently manifested

♦  Maximizing SPR time virtually eliminates any outpost utilization (IVA or EVA) •  Additional time for outpost utilization (local EVA or lab in hab) will reduce total excursion days

♦  Average time per crew devoted to “work” items = 7.0 hours/day (7 days a week) •  5.7 hours/day on ISS

♦  Total fraction of surface time committed to utilization (including driving) = 12% •  All of which is in the SPR

Personal (87 hrs)

Exercise (374 hrs)

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0

500

1000

1500

2000

2500

3000

0 10 20 30 40 50 60 70 80

Outpost Utilization Time

♦  Results attempt to maximize SPR excursion days, once outpost time requirements have been satisfied (non-utilization)

♦  No remaining time for utilization at the outpost - Local EVA, rock sorting, lab in hab, etc.

♦  EVA rate at outpost is far less than allowable - 123 hours out of 1536 hours allowable (8%)

♦  Increased outpost utilization time will directly decrease excursion time

♦  Similarly, any added outpost tasks (berming, site prep., regolith moving) will decrease SPR time

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0

5000

10000

15000

20000

25000

30000

35000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

0

0.05

0.1

0.15

0.2

0.25

Scenario Results - 4.2.1

♦  Initial utilization is low •  Large build-up •  Limited surface days •  “ISS-Like”

♦  Average utilization across across scenario = 3.9 hours/day/crew (including driving)

♦  SPR days more limited on initial missions •  Only achieve 60% of

excursion days in current manifest on first five crewed mission

•  85% over scenario

♦  SPR IVA Utilization time averages approx. 7.1 hours/day/crew (incl. driving time)

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Outpost Sleep/PS 27.1%

Outpost IVA Maintenance/Set-Up 3.4%

Outpost IVA Work Time Liens

8.0%

SPR IVA Utilization/ Driving 10.0%

SPR Utilization EVA 6.0%

SPR Food/Meals 3.0%

SPR Sleep/PS 14.5%

SPR Work Time Liens 1.4%

Outpost IVA Utilization 0.4%

Outpost EVA 1.0%

Pro-Rated SPR Liens 7.4%

Outpost Exercise/Med 3.9% Outpost Food/Meals

5.5%

Outpost R&R/Personal 8.3%

Total SPR Time 34.9%

Total Outpost Time 65.1%

Scenario Results - 4.2.1 (cont.)

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Inside Hab (61%)

Hab EVA (1%)

Inside SPR (31%)

SPR EVA (7%)

Inside Hab (54%)

Hab EVA (1%)

Inside SPR (41%)

SPR EVA (4%)

Inside Hab (50%)

Inside SPR (36%)

Hab EVA (5%)

SPR EVA (9%)

SPR EVA Options Projected Current Manifesting

(no crew time restrictions)

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Path Forward ♦  Need to work with functional area leads to identify opportunities to improve time

requirements for various areas of operation

♦  Model can be used to establish goals: •  ~10% reduction required across the board for all crew time liens in order to enable full current manifested

excursion days (80 days per 180 day increment) - 14 hour/week/crew reduction

•  ~30% reduction required across the board for all crew time liens in order to enable full current manifested excursion days PLUS full EVA schedule at the outpost - 41.9 hour/week/crew reduction

•  ~40% reduction across the board for all crew time liens in order to enable full current manifested excursion days PLUS full EVA schedule at the outpost PLUS ~60 hours per week of IVA utilization - 55.8 hour/week/crew reduction

•  Since certain liens likely cannot be significantly reduced, larger gains will be required in other areas

Task Type LSS Time Weekly Estimate (Hours/Crew) Routine Ops 3.0 Inspection 1.5 Conference / Tag-Ups 7.0 Training 2.0 Work Prep 3.0 Traffic 0.0 Medical 4.0 Public Relations 1.5 Stowage / Inventory 1.0

Exercise 10.0 Food Prep 2.0 Meals 12.25 Pre / Post Sleep 10.5 Sleep 59.5 Personal Comm. 1.5 R&R 20.0

Margin 0.75

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Future Issues

♦  Initial LSS Maintenance & Repair estimates are substantially lower than ISS historical data •  Pushing to lower-level repair will increase time •  More sophisticated ECLSS and mobility will increase time •  On-site manufacturing & scavenging will increase time •  No inclusion of “infant mortality”

♦  Additional outpost tasking will further reduce excursion capability •  Site prep •  Landing pads / moving of landers •  Moving of regolith for radiation protection •  ISRU support

♦  There is potential for use of robotics and tele-operations to reduce certain time requirements