Upload
others
View
0
Download
0
Embed Size (px)
Citation preview
Page 1
Chel Stromgren Strategic Analysis Team
January 14, 2009
Lunar Surface Systems Crew Time Analysis Overview
Page 2
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
Page 3
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
Page 4
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
Page 5
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
Page 6
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
Page 7
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
Page 8
♦ 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)
Page 9
Maintenance & Repair Time Estimates
Page 10
Offloading/Set-Up/Outfitting Time Estimates
Page 11
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
Page 12
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)
Page 13
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
Page 14
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)
Page 15
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.)
Page 16
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)
Page 17
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
Page 18
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