**Foundations of Supply Chain Management**

**for Space Application**

*By Michael Galluzzi, NASA*[^1]

*NASA Kennedy Space Center, Florida 32899*

*Edgar Zapata, NASA*[^2]

*NASA Kennedy Space Center, Florida 32899*

*Martin Steele, Ph.D. NASA*[^3]

*NASA Kennedy Space Center, Florida 32899*

*Olivier de Weck, Ph.D.*[^4]

*Massachusetts Institute of Technology*

*77 Massachusetts Ave,Cambridge, Massachusetts, 02139*

**Supply Chain Management (SCM) is a key piece of the framework for
America's space technology investment as the National Aeronautics and
Space Administration (NASA), the aerospace industry, and international
partners embark on a bold new vision of human and robotic space
exploration beyond Low-Earth-Orbit (LEO). This type of investment is
driven by the Agency's need for cost efficient operational support
associated with, processing and operating space vehicles and address
many of the biggest operational challenge including extremely tight
funding profiles, seamless program-to-program transition activities and
the reduction of the time gap with human spaceflight capabilities in the
post-Shuttle era. An investment of this magnitude is a multiyear task
and must include new patterns of thought within the engineering
community to respect the importance of SCM and the integration of the
material and information flow. Experience within the Department of
Defense and commercial sectors which has shown that support cost
reductions and or avoidances of upwards to 35% over business as usual
are achievable. It is SCM that will ultimately bring the solar system
within the economic sphere of our society.**

**Applying aspects of the high-volume, market demand driven SCM
disciplines of the commercial industry to a low-volume, schedule driven
aerospace environment is not only possible but vital to accurately
estimate, plan, control and manage the non-recurring and recurring costs
associated with long-term operations and vehicle processing of space
flight and ground support equipment. Applying these disciplines is
especially crucial during the early design, development, test and
engineering (DDT&E) phase of a new program. Upwards of 70 to 80% of the
operational recurring costs, which include 90% of the indirect
processing costs associated with Launch and Landing core activities, are
influenced as a result of this initial phase of the product lifecycle.
Breakthroughs in the commercial field of SCM are giving top-level
commercial industry operations and production managers the forecasting
and integration capability needed to create a just-in-time and on-demand
rapid mobilization of manufacturing sources.**

**Comparatively, as we turn our attention to very large space endeavors,
delegation of sustainment activities from the Program to the Project
Offices, complicates the integration and forecasting of material and
information flows, and could prevent true integration from ever being
achieved. Good collaborative forecasting, planning and realistic
replenishment scheduling is essential to an effective SCM practice
especially, when considering simultaneous non-serial activity of diverse
new programs anticipated for future Lunar and Mars expeditions.**

> **Acknowledgements**

This work was completed as part of the Explorations Systems Mission
Directorate, Integrated Modeling and Simulation Group. Michael Galluzzi
of NASA's Kennedy Space Center and Dr. Mansooreh Mollaghasemi of
Productivity Apex, Inc., served as key investigators on the
Earth-to-Orbit Modeling Simulation with Edgar Zapata from NASA's Kennedy
Space Center as COTR. Additionally, the Interplanetary Supply Chain
Management & Logistics Architectures Project under contract NNKO5OA50C,
Prof. Olivier de Weck and Prof. David Simchi-Levi, Massachusetts
Institute of Technology, served as the principal investigators, with Dr.
Martin Steele from NASA's Kennedy Space Center as COTR. Dr. Mohamed
Fayez, Michael Callinan of Productivity Apex, were instrumental in
providing valuable insight and feedback, as were Michael McClain, Scott
Sealing from the United Space Alliance and Dan Swartwood of PRAGMATECK
Consulting Gp, Inc. in defining Supply Chain Council "SCOR". We also
thank Jack Molchany, Program Manager of Concurrent Technologies
Corporation for providing new insight to the DLA-DoD B3i Program.

I.  **Introduction**

In May of 2004, the Government Accounting Office sent a Report to the
Subcommittee on Space and Aeronautics, Committee on Science, House of
Representatives titled "NASA's lack of Disciplined Cost-estimating
Processes Undermines NASA's Ability to Effectively Manage its Programs".
This report recommended that NASA develop an integrated plan to, among
other things, staff and support for cost-estimating and full cost
management through Earned Value Management (EVM), which helps identify
variances before they disrupt the program and ties directly to the 1996
Federal Financial Management Improvement Act (FFMIA). It also
recommended establishing a standard framework for lifecycle cost
estimates through use of a Cost Analysis Data Requirements (CADRe) model
and to focus on the Agencies materials and Plant, Property and Equipment
(PP&E), which includes space flight and ground support equipment as well
as infrastructure and facility assets. Before we can comment on NASA's
cratered budgetary landscape and years of "Unqualified" or "Disclaim"
opinion by the auditors, we must get a better understanding of PP&E
assets, how these assets came to be, how inventory assets are managed,
how supplier and product-line viability can impact the cost estimating
process and finally how SCM simulation and modeling can help in the
future.

It is our hope that this paper will motivate the aerospace community in
deploying the fundamentals of SCM along with simulation and modeling
breakthroughs with the objective of growing a risk shared endeavor
between customer and contractor, that utilizes an integrated and cost
effective supply chain through collaborative demand planning, Component
Supply Management (CSM), product standardization, rapid mobilization of
consolidated manufacturing sources and SCM simulation and modeling.
"Often times, a supply chain is thought of only in terms of Integrated
Logistical Support (ILS), and within the ILS exists the need to sustain
a viable supplier base. While this is an important and critical function
for the success of any endeavor, ILS is better considered as an enabler
to the entire supply chain rather than the supply chain itself, when
that supply chain is defined in terms of the enterprise or program. In
today's environment, the supply chain truly encompasses a much broader
spectrum."[^5] A SCM process can be defined further as an integrated
network of materials and information flow supporting a common hardware
sparing and repair philosophy throughout a program for long-term support
of space exploration. A NASA supply chain implementation brings the
methodology needed for planning and executing:

1)  The selection of flexible and reliable sources of supply during the
    entire system lifecycle

2)  Agile manufacturing and procurement processes that can rapidly
    respond to unknown and changing elasticity in demand

3)  Good collaborative probabilistic supply/demand forecasting in
    executable form with procedural representation of the processes

4)  Key performance indicator metrics based on the Supply Chain
    Operations Reference Model (SCOR) and used to guide improvement
    investments.

"A driving force behind SCM is the recognition that suboptimization
occurs if each organization in the supply chain attempts to optimize its
own results rather than to integrate its goals and activities with other
organizations to optimize the results of the chain."[^6] We are
[not]{.underline} implying a central, logistics architecture or
Performance Based Logistics (PBL) concept but rather a re-definition of
commercial SCM in the context of human space flight activities. Within
the NASA and Aerospace community, the logistics of it, and it's
planning, sustainment, sparing and repair, as well as a host of other
functions will be shown as completely applicable to a perspective as a
series of plan, make, source, deliver and return steps -- The Supply
Chain Council's SCOR steps.

Finally but more importantly, this paper addresses how SCM is more than
just low costs and lean efficiency; it shows how the aerospace industry
can shape and respond to changes in demand pressures while allowing for
insertion of new technology and processes without new congressional
funding appropriations or departmental reorganization. What we are
addressing is a representation and conscious effort to manage the many
layers of "logistical" activities from both the strategic and tactical
approach. We have also determined that this framework can be
accomplished within proper interpretation of the existing NASA Policy
Directives (NPD) for Procurement, Program Management and Logistics. We
will also redefine the Supply Chain Councils' five step process but with
a NASA-wide deployment strategy. Success with this endeavor will require
process improvement, technology, money and people. The efficiencies
gained will result from integration, collaboration and planning.
Efficient, agile and cost effective will become the standard.

**II. Understanding Launch and Landing Costs**

In terms of process definition, drivers of these, relationships to fixed
and variable costs, relationships to flight and ground system design and
potential business processes and Information Technology (IT) systems
changes that could improve these functions, requires a new Product
Lifecycle and Supply Chain modeling and simulation approach and
capability. Such an approach of necessity is focused on understanding
multi-attribute influence relationships during the life of the Program
that can support multi-attribute decision making. In effect, the
decision making space is enriched, as a SCM perspective discovers and
then opens up areas for improvement that are traditionally taken as a
given, or accounted for as business as usual. As an example, consider
the following question: What is the change in launch and landing ground
operations if the new Crew Exploration Vehicle ("Orion") service module
uses one propellant vs. another. Traditionally such a question is
answered by looking only at those portions of the analysis tree or
influences that derive from such a technical change. Such an analysis
assumes "business as usual and static funding levels" for all indirect
costs, and enabling functions, as no such capability currently exists to
analyze "what if" factors related to the content of those indirect or
enabling functions. The largest percentage of the Launch and Landing
indirect costs would include KSC Ground Operations, Infrastructure and
Flight Element Logistics. See Figure 1.

![](media/image1.jpeg){width="6.5in" height="4.875in"}

**Fig.1: Breakdown of direct and indirect processing costs for Launch
and Landing operations**

Alternately, besides changing a propellant, one can also change the
business processes that support readying that system. Factors would of
necessity address:

1)  Best practices

2)  Process re-engineering

3)  Information flows

4)  IT systems

5)  Material flows

6)  Budget Appropriations

The result of the prior influence relationships is a definition of
plausible actions that can be pursued further as most promising.
Consider another example the functions inherent in indirect prime
contractor functions at a launch site such as the Kennedy Space Center.
The Supply Chain Management, Business Process and IT Systems employed
drive this category of indirect prime contractor functions which
include:

1)  Program interfaces / coordination, rules management (LCC, Orbiter
    Maintenance Requirements Schedule (ORMSD), etc)

2)  Requirements management and flow-down

3)  Generate work documents

4)  Configuration management

    a.  Documentation, work authorization, tracking

5)  Work control

6)  Scheduling

    a.  Interface tasks into master scheduling and manifest and schedule
        daily work

7)  Dedicated ground systems support, design, planning, and operations
    and maintenance (O&M).

As the prior categories of indirect costs comprise 50% of Launch and
Landing prime contractor costs, and to the degree the size of theses
functions rely on the business processes and information systems that
are at the heart of these functions, and to the degree that these costs
are independent of the product lifecycle, in this case flight and ground
system design, then a quantified understanding of how SCM improvements
affect such a category is crucial to improvements in overall space
transportation systems costs and productivity. The prior area does not
even include the actual "deliver" component of logistics by the prime
contractor, which is accounted for separately - another area ripe for
the application of advanced SCM practices.

Additionally, the NASA portion of the supply chain, here from the
perspective as customer "sourcing" (rather than the contractor category
of "delivering" using the SCOR framework liberally) has many of the same
indirect or enabling functions that merit analyzing. *To what degree are
these functions independent of the flight and ground system product
design?* It is estimated that a category of costs traditionally referred
to as G&A (General and Administrative) and Service Pools, what the
Agency now calls Center Management and Operations, or CMO to include
Safety and Mission Assurance (S&MA) in FY08, constitute up to \$2.5
Billion dollars of the annual NASA budget (less S&MA). At just NASA's
Kennedy Space Center alone, the amount may be some \$300M a year of
content associated with information and material flows such as finance,
procurement, and assorted initiatives associated with the infrastructure
that flow information and material to enable the more visible activity
of launches. Once again, modeling the content as supply chain functions,
such as within a SCOR framework, lays the ground to attach an action,
(such as a specific best practice or a specific business process change)
to a measurable thing such as cost or turnaround of a processes product.

Lastly, an integrated approach applying SCM factors as well as modeling
the actual product parameters, flight and ground systems design, accepts
that the influence relationships even at a macro-level of an entire
operation such as NASA KSC Launch and Landing, are a rich tapestry of an
inter-connected thread of influences as shown in Figure 2.

![](media/image2.png){width="6.481944444444444in"
height="4.413888888888889in"}

**Fig.2: Supply Chain influence diagram**

These influences must be wrapped together, within frameworks that seek
to present simple but powerful relationships about a complex system and
its phase of the system lifecycle. It must answer questions of how to
build a system for supportability, iterate on design parameters in a
multi-dimensional trade space to achieve a specific behavior and support
characteristic and do it in a distributed interactive virtual
environment. As an example, we can use the correlated relationship of
traditional cost patterns to a systems lifecycle (Figure 3).

![](media/image3.jpeg){width="4.25in" height="3.1875in"}

**Fig. 3: Product Lifecycle cost "bellcurve" model**

**III. Earth-to-Orbit Supply Chain Simulation Modeling**

We have so far addressed tactical approaches so now let's focus on the
strategic. Strategic analysis capabilities can and are being developed
to influence future directions for NASA space transportation systems
developments and operations, to assist decision making and to quantify
the numerous inter-relationships described herein. The NASA
Earth-to-Orbit Supply Chain Simulation for Exploration is a project in
work sponsored by the NASA Explorations Systems Mission Directorate as
part of the Integrated Modeling and Simulation portfolio of products.

Why Supply Chain Management at NASA and why now? Because SCM offers a
powerful end-to-end perspective and practice very applicable to NASA
needs for developing Exploration supply chains that are flexible,
responsive and sustainable.

Borrowing a definition from Wikipedia, "Exploration is the act of
[searching](http://en.wikipedia.org/wiki/Search) or
[traveling](http://en.wikipedia.org/wiki/Travel) for the purpose of
discovery, e.g. of unknown regions, including
[space](http://en.wikipedia.org/wiki/Outer_space) ([space
exploration](http://en.wikipedia.org/wiki/Space_exploration)), or
[oil](http://en.wikipedia.org/wiki/Petroleum),
[gas](http://en.wikipedia.org/wiki/Gas),
[coal](http://en.wikipedia.org/wiki/Coal),
[ores](http://en.wikipedia.org/wiki/Ore),
[caves](http://en.wikipedia.org/wiki/Cave),
[water](http://en.wikipedia.org/wiki/Water) (also known as
[prospecting](http://en.wikipedia.org/wiki/Prospecting)), or
[information](http://en.wikipedia.org/wiki/Information)." In the case of
NASA our explorers will require extended support systems of material and
information as the uniqueness of the endeavor will define an extended
supply chain on Earth up to a Spaceport node, including its processes
and the final launch point node on the ground. Once in space, the chain
will extend outwards with information and material flows. Eventually
material will flow in both directions, with crew returning, hardware
being delivered to planetary outposts, and materials such as rocks and
specimens, being returned to Earth from other Planets. A SCM analysis
capability is strategic as it:

1)  Is where most of the costs will reside for future space
    transportation systems if trends oberserved in the past will persist
    in the future, namely: most costs are bound up in operations.

2)  Is an analytical capability that is possible now, due to advances in
    both handling knowledge and in simulation techniques

3)  Is a technique that is adaptable to new technology in the product
    lines (e.g. future block upgrades of CEV)

4)  Is adaptable at the Enterprise / macro-level view from requirements
    to launch execution

5)  Can represent systems that have both information and material flows,
    especially suitable to lower volume aerospace applications

6)  Is life-cycle focused

We define an Exploration Supply Chain as:

"The integration of NASA centers, facilities, third party enterprises
and international partners, orbital entities, space locations, and space
carriers that network/partner together to plan, execute, and enable an
Exploration mission that will deliver an Exploration product (crew,
supplies, data, information, knowledge, physical samples) and to provide
the after delivery support, services, and returns that may be requested
by the customer." Notionally, an abstracted visual representation of
such a system is shown in Fig. 4:

![](media/image4.jpeg){width="6.6090277777777775in"
height="3.370138888888889in"}

**Fig. 4: Asbtracted visualization of the end-to-end space exploration
supply chain with material flows, information flows and main processes
on Earth, in Space and at Planetary locations.**

Such a capability is developing using the Supply Chain Council "SCOR"
Model, the Supply Chain Operations Reference model. In this process the
standard 5 processes of plan, source, make, deliver and return, and the
more detailed sub-processes, are taken and the current NASA processes
are mapped into these. Center's and contractors (especially prime
contractors) become "functional units" as in a distributed business with
numerous entities contributing sub-assemblies, information and value to
steps leading to finished products. The process highlights redundancies,
or duplication as well as choke-points once represented in a time-based
discrete event simulation. In this case the product is a launch, but the
actual product may more specifically be said to be a requirement that
has been accomplished, as this may be the return of scientific
information or planetary specimens, from the point of view that the
transportation is incidental (odd as that may sound). To manage all the
knowledge required, an ontology is being developed for such a simulation
to be effective, as such a knowledge based approach circumvents issues
which even sophisticated data-base approaches can not resolve.

As of this writing the initial Phase I of this project has been
completed, addressing ontology, simulation and user interface
development, minus the integration of these and the necessary depth in
order to provide useful analysis. In Phase 2 of this project that is
underway, the depth and the integration of all 3 aspects of the
Earth-to-Orbit simulation are being further developed so as to lead to a
useful analysis capability in mid-2007.

**IV. Interplanetary Supply Chain Simulation Modeling**

Sustainable space exploration, however, is impossible without
appropriate SCM beyond Earth. Unlike Apollo, future exploration will
rely on a complex supply-chain
[network](http://spacelogistics.mit.edu/network.htm) on the ground
[and]{.underline} in space. The primary goal of the NASA-funded project
Interplanetary Supply Chain Management and Logistics Architectures
(ISCM&LA) is to develop a comprehensive [SCM
framework](http://spacelogistics.mit.edu/modeling_framework.htm) and
[planning tool](http://spacelogistics.mit.edu/space_net.htm) for
space-logistics, focusing on the in space portion of the supply chain.
Four segments of this project include Terrestrial Supply Chain
Analogies, Space Logistics Network Analysis, and Exploration
Demand-Supply Modeling with Uncertainty, and Interplanetary Supply Chain
Architecture Trade Studies. More detailed papers, reports and
information about the project are available at:
[http://spacelogistics.mit.edu](http://spacelogistics.mit.edu/)

### A. Terrestrial Supply Chain Analogies and Space Logistics Lessons Learned

The Terrestrial Supply Chain Analogies segment of this project
investigated and contrasted lessons learned from SCM in (i) major
industries specialized in "low-quantity", capital-intensive products,
(ii) long-range [military](http://spacelogistics.mit.edu/military.htm)
operations such as aircraft and naval-submarine logistics, and (iii)
supply-chains for operations in [remote
environments](http://spacelogistics.mit.edu/hmp.htm). For the remote
environments effort, an expedition to the Haughton Mars Project (HMP) in
the Canadian high Arctic (75N 90W) was undertaken to obtain first hand
knowledge of logistics commodity & information flow in a remote
environment[^7]. In supporting the logistics analysis of the HMP, the
following was accomplished:

1)  Development and validation of classes of supply items for
    applicability to space logistics

2)  Development of a nodal model of transportation modes to assess the
    unit cost, time and availability, and the bulk-density and
    criticality of goods transported

3)  Experiment with Bar Code and Radio Frequency Identification (ID)
    methods of supply tracking and management

A full report of the HMP expedition and a companion report on space
logistics lessons learned are published in NASA Technical Publications
(TP-2006-214196, Haughton-Mars Project Expedition 2005 and
TP-2006-214203, Logistics Lessons Learned in NASA Space Flight). The top
seven lessons learned from past manned spaceflight programs (Spacelab,
Shuttle, ISS, ...) in space logistics are:

1.  Incorporating stowage requirements in vehicle design specifications

2.  Requiring a common logistics/inventory system across multiple
    organizations

3.  The logistics information system should intuitively accommodate the
    movement of parent-child relationships

4.  Commonality is a prime consideration for all vehicles, systems,
    components, and software

5.  Design for maintenance is a primary consideration in reducing the
    logistics footprint

6.  Plan for and apply standards in system development

7.  Include return logistics in the design/specification

### B. Space Logistics network analysis (SpaceNet)

The space logistics network model contains nodes in the Earth-Moon-Mars
system, including Lagrangian points and expected landing-exploration
sites, and arcs representing crew/cargo and vehicle element flows
between the nodes. The crew and cargo are manifested into individual
flights. With this model, testing various scenarios is possible to
determine the benefits of different logistics philosophies from
*pre-deployment to carry-along to re-supply*. Optimizing the right mix
of these complementary strategies is the most important aspect of space
exploration logistics from a space-based (as opposed to ground-based)
perspective. One unique point differentiating terrestrial from space
nodal networks is that the in-space nodes are in constant relative
motion to one another, creating time and energy dependencies in the
network. Meeting critical demand requirements calls for considering
these dependencies in the supply flow analysis. To this end, the
SpaceNet discrete event simulation model is in development. (see Fig..
5).

SpaceNet[^8] is a demand driven discrete event simulation and
optimization software for space logistics. Currently, version 1.2 is
under development in a Matlab/Excel-based environment. The main
components of SpaceNet are:

-   *Movement* or shipment of people, cargo, and vehicles

-   *Demand* by supply class

-   *Information architecture*

-   *Simulation*

-   *Optimization*

The challenge that SpaceNet addresses is to integrate models for
shipment strategies and demand with the information architecture, then
wrap these components together under a simulation layer, and incorporate
some degree of optimization. The key is the recognition that -- similar
to terrestrial SCM - the space exploration logistics scenarios are
largely *demand-driven*. When demand 'arises' at a lunar surface base,
shipments must be allocated to fill it. Demand, in turn, is determined
by the mission scenario -- the length and location of surface stay, type
of interplanetary transfer, number of astronauts, science mission, etc.
By allowing demand to drive shipments, then selecting various shipment
strategies, a large number of approaches can be tested for the same
mission scenario. A schematic overview of the model is shown in Figure
5.

The demand levels are determined by the mission scenario, which is input
by the user. The next step is to model various shipment strategies. This
is quite a complex problem, because the decision space is very large and
often difficult to describe. The solution is to borrow from the
terrestrial logistics field and model the transportation options as a
series of nodes and arcs. Nodes represent locations such as Kennedy
Space Center (KSC) or LEO, while arcs represent the trajectories between
nodes, such as chemical rocket trajectories from LEO to EM-L1, launch
trajectories from the lunar surface to LLO, or even driving routes from
a Martian base to a science target. In addition, astrophysical
constraints dictate a time-dependence in the cost (in terms of
propellant) of traveling each arc, which does not exist in most
terrestrial cases. A time-expanded network is therefore utilized. With
this modeling solution, the cost of any given logistics solution can be
modeled by summing the costs of traveling arcs and waiting at nodes. Any
shipment strategy can be modeled by choosing various paths through the
network (Fig. 6).![](media/image5.wmf){width="6.175in"
height="2.745138888888889in"}

![](media/image6.png){width="5.435416666666667in"
height="2.890972222222222in"}

**Fig. 6: Baseline NASA Constellation Lunar Sortie scenario modeled in
SpaceNet v1.2. The x-axis shows time in units of Earth days, the y-axis
shows various Earth, Space and Lunar nodes. Processes modeled include:
transporting, waiting, exploring, docking/undocking and transferring
crew and cargo from one element (vehicle) to another.**

The information architecture takes the form of a relational database
incorporating all aspects of the model: the input mission scenario,
demand models, nodes and arcs, and output data (details of the
relational database are available in a separate paper). All software
modules interact with the same database, ensuring a consistent
information architecture for the diverse functions of the model.

Optimization is incorporated at the level of the transportation network.
Given inputs of demand at various nodes and times, the optimization
chooses the best shipment path through the network, based on the
available vehicles, nodes, and arcs. The shipment paths can also be
chosen manually, in order to enable trade studies. For example, by
choosing shipment paths which force all supplies to travel well before
the crew, pre-positioning strategies can be evaluated.

Finally, the simulation layer takes all the data generated by other
modules: the demand levels, shipment paths, vehicles utilized, etc. and
simulates the logistics scenario in Matlab. The simulation ensures that
demand levels are in fact met by the shipment strategy chosen, that
demand generated along arcs (e.g. crew traveling to Mars) is satisfied,
that vehicles carry enough fuel for the journey, etc.. The simulation
also incorporates a visualization of the network and the shipment
strategy, which is a valuable tool for developing an intuitive
understanding of various logistics solutions.

In Apollo-style (sortie) missions, where all supplies are carried
on-board for short duration missions, essentially all logistics support
exists on the ground. This is a very truncated supply chain. On the
other hand, for long duration missions (lunar outposts), the supply
chain extends into space and to the point of exploration on the surface
of the moon/Mars or on the ISS. The (simple) nodal perspective of the
growth in the space supply chain shows the increase in complexity that
demands careful planning (Fig. 7). SpaceNet is designed to model these
networks and easily accommodate the addition of nodes and vehicles to
support the analysis of the evolving exploration era supply chain. The
user inputs supply demand, transportation capability and schedules, and
nodal parameters to obtain various measures of effectiveness pertaining
to satisfaction of exploration mission requirements.

![](media/image7.jpeg){width="5.0in" height="3.75in"}

**Fig. 7: Evolution of space supply chains from Apollo to the present
(ISS) and future**

Uncertainties in [supply and
demand](http://spacelogistics.mit.edu/demand.htm) of the space logistics
network, such as demand variations, changes in the cargo-mix,
transportation costs, and unplanned supply-line interruptions, are
important considerations when performing supply chain analyses, as well
as storage and lifetime issues (degradation, obsolescence, cryo-boiloff)
and consumption rates. Populating the supply-chain network model to run
these various logistics scenarios, starting with CEV development and
deployment (2010-2014), all the way to lunar sortie missions (2018-2020)
and the buildup of a lunar outpost (2021-2023) allows critical analysis
of supply chain effectiveness prior to implementation. SpaceNet
incorporates 10 functional classes-of-supply (COS), including
propellants, crew consumables, spares, and exploration and mobility
equipment, for the analysis of exploration logistics, which were
developed and validated during the terrestrial analogies and space
logistics lessons learned segment of this project.

Incorporation of supply/demand uncertainties with the SpaceNet discrete
event simulation model allows the execution [trade
studies](http://spacelogistics.mit.edu/scenarios.htm) to help answer
questions with regard to launch and space vehicle assignment mix,
location of ground facilities and in-space transfer points, and
logistics and information architectures boundaries. Combining trade
studies to analyze the support requirements of both the International
Space Station (ISS) and lunar missions is crucial to flight planning of
current and future vehicles.

**V. Collaborative Planning within the NASA Policy Guidelines**

A SCM operational architecture will stimulate improved project element
collaboration, hardware demand planning, component production
forecasting, workforce scheduling and Maintenance, Repair and Overhaul
(MRO) hardware procurements throughout the life of NASA's next
generation of Launch Vehicles. The functional architecture is designed
to provide the Agency with a seamless information flow necessary to
strengthen an efficient hardware spares and repair philosophy while
maintaining a healthy supply base and a NASA-Center Repair Depot
capability specifically chartered for conducting logical Failure Modes,
Effects, and Criticality Analysis (FMECA) and rapid manufacturing
capability for unanticipated hardware demand during a near-launch 60 day
window.

The process known as collaborative planning, forecasting and
replenishment (CPFR), to include MRO, is an integral part of the NASA
supply chain. CPFR is the sharing of forecasts and related business
information among business partners in the supply chain to enable
automatic product replenishment. The CPFR technique takes the common
supply chain network and shares asset information in very near real
time, ultimately this could stimulate a collaborative dialogue between
the different project elements and qualified suppliers but spearheaded
by the NASA Program Office. The CPFR process falls well within with the
guidelines of the Shuttle Programs NSTS 07700 Vol XII document, which
defines the Space Shuttle logistics and supportability requirements and,
depending upon interpretation of the existing but sometimes ambiguous
NASA Policy Directives (NPD), specifically 7500.1a Program and Project
Logistics Policy, 7120.5c Program and Project Management Processes and
Requirements, NPD 4100.1a Supply Support and Materials Management and
NPD 5900.1 Spare Parts Acquisition. The CPFR process allows for planning
information with regards to asset demand forecasting, hardware
production schedules and other demand generation requirements. It
assists with planning the process using actual demand and hardware
failure data and generating a plan for sourcing what SCOR calls (P2),
manufacturing (P3), delivering (P4) and return (P5) of the correct
asset. "Asset" defined in this case as property (real or personal),
suppliers and people with a positive value. Ultimately, NASA and the
contractor community will have a smooth flow of shared asset information
across the agency to achieve a "world-class" response time with order
fulfillment and to focus better on core planning and financial budgeting
competencies.

Below is an example to further expand on what we mean when we refer to
the sustainment NPD's being ambiguous and is our interpretation. Note
that we focused on sections within the policies but highly recommend the
reader go to the NASA main website and read these policies in full and
develop an independent interpretation and conclusion.

**A. NPD 7500.1a Logistics Policy**

"Agency-funded programs and projects which produce reusable or
maintainable flight or ground hardware will apply Integrated Logistic
Support engineering and management concepts and techniques to all phases
of the program or project cycle to ensure the new or upgraded system
will be economically supported through its planned life"...

1)  **[Responsibility]{.underline}** Assistant Administrator for
    Infrastructure and Administration Management, compliance by Center
    Directors

2)  **Assessment** The Policy leaves the Assistant Administrator
    responsible for "brick and mortar" infrastructure and facilities
    ultimately responsible for supporting and governing policy on
    "engineered systems" e.g. space flight hardware & GSE "systems
    logistics". The implementation of the policy is not fully or
    completely implemented possibly because NPD 7120.5c creates lack of
    clarity by placing responsibility on the Program [and]{.underline}
    Project Offices which 7500.1a also states that the "Programs and
    Projects will (an expectation, not a requirement) conduct Logistics
    Supportability Assessment regiment..." thus creating a lack of core
    capability within the top level agency officials for Flight and GSE
    Equipment

**B. NPD 7120.5c Program and Project Management**

"...describes the management system by which NASA shall formulate,
approve, implement, and evaluate all programs and projects established
for safe development and operation of aeronautical and space ground and
flight systems and technologies."

1)  **Responsibility:** Spans the NASA Management Chain; compliance by
    the Agency Program Management Council and Chief Engineer

2)  **Assessment:** NASA Policy [Requirement]{.underline} (NPR) 7120.5B
    state "the project office **shall** (a requirement) establish a
    logistics requirement per NPD 7500.1A to identify lifecycle cost
    drivers for design support..." The overall program requirements i.e.
    Sustainment/Logistics and Supply Chain are levied on the Program
    Office but the flexibility of the materials and information
    integration is "interdependent" of the projects. Project Office has
    the ultimate responsibility not the Program and in some cases
    delegated to the contractor.

**C. NPD 5900.1a NASA Spare Parts Acquisition**

"The Spare Parts Acquisition Policy establishes a uniform policy for the
acquisition and provisioning of NASA spare parts. Program
managers/Enterprise Associate Administrators have the overall
responsibility for spare parts management for programs under their
cognizance. Program managers are responsible for direction and
management of spare parts required to support their assigned
system...Logistics/program managers are responsible for establishing
logistics support methodologies for systems..."

1)  **Responsibility:** Procurement Office

2)  **Assessment:** This NPR establishes a uniform policy for the
    acquisition and provisioning of NASA spare parts. Replenishment
    defined by this NPR means "the process of pricing, ordering, and
    stocking spare parts needed to maintain or repair a major system
    over its life based upon the initial provisioning list and usage
    patterns established during the initial provisioning period.
    Replenishment begins when the initial provisioning period ends.
    Either the Government or a designated contractor, where it has
    proven to be cost effective, may accomplish replenishment." However,
    NPD 4100.1a states "Maximize the use of outsourcing and trading
    partner inventories (e.g., Just-in-Time/JIT) as the primary method
    for stores, program, and standby stock material requirements.
    Material should not be warehoused at a Center unless there is no
    cost-effective alternative." This policy limits technology infusion
    later in the PLM as an alternate Diminishing Manufacturing Source
    and Material Shortages (DMSMS) mitigation path - assumes stock
    piling inventory and does not consider JIT for replenishment on
    reusable systems. Assumes systems are nonexpendable with trailing
    repair and sparing philosophy to support inventory stockpile. More
    importantly it identifies either Program [or]{.underline} Project or
    the Contractor to make a determination of LOT buys. Similarly,
    maverick procurement may occur when there are similar programs using
    the same product line leaving redundant procurement activity within
    NASA competing against the other project office and not negotiating
    one lot buy for the program instead of one lot buy for the project.
    This is further exacerbated by leaving ILS activities to the
    contractor thus leaving potential for an inflated price due to the
    addition of contractor SG&A and profit to the final price.

**D. NPD 4100.1a Supply Support and Materials Management**

"Supply support and material management shall be structured to be
responsive to customer requirements at minimum cost and demand on the
NASA logistics infrastructure." "...This policy shall be incorporated in
all contracts for onsite NASA material management/supply support."

1)  **Responsibility:** Assistant Administrator for Infrastructure and
    Corporate Management, compliance by Center Directors

2)  **Assessment:** Combines institutional supply with flight, GSE and
    STE requirements but puts supply support and material management
    requirements in contracts under their purview. Center Directors are
    to appoint a supply and equipment management office (SEMO), an
    Inventory Adjustment Officer and responsible for establishing supply
    support and management of material requirements for their
    program/projects. Creates lack of clarity between NPD 7120.5C, NPR
    7120 and NPD 7500.1a.

**E. NSTS 07700 Vol. XII Space Shuttle Logistics and Supportability
Requirements**

Original document baseline April 1973, "The Manager, Space Shuttle
Program (SSP) shall be responsible for developing and maintaining the
Program Logistics requirements. The Space Shuttle Project Element
Managers shall be responsible for developing, maintaining, and
implementing logistics support to ensure compliance with the
requirements of this document. The Manager, SSP Logistics shall be
responsible for ensuring logistics integration across the Program."

1)  **Responsibility:** SSP Program Office Logistics Manager

2)  **Assessment:** NSTS 07700 contains several volumes providing
    program level requirements for the SSP. This volume provides
    requirements for a comprehensive logistics program to assure that
    flight hardware and ground systems are maintained to their design
    performance. The project elements of the SSP must establish
    logistics processes and systems to adhere to these requirements for
    maintenance, supply support, packaging, handling, storage, and
    transportation, and personnel training. These logistics activities
    are performed by each element; however, some elements apply them
    differently. Eg. the elements still in production, Reusable Solid
    Rocket Motor and External Tank, define logistics as that support
    provided only for hardware delivered to KSC, not to the production
    of flight hardware. Orbiter, Space Shuttle Main Engine, and Solid
    Rocket Booster apply them to the repair, maintenance, and overhaul
    of their hardware.

When inventory is a necessity at multiple logistic nodes and hardware
sparing is the driver, the Agency could outsource the "busy work"
associated with procurement of inventory after negotiations have taken
place, and leave the spares and production forecasting responsibilities
to NASA. This would also include the busy work associated with
monitoring the repair activities/responsibilities to contracted partners
but only with a tight contractual agreement or Contract Data
Requirements List (CDRL) and link these "partners" on a more intimate
level by integrating within the NASA SCM shared information network and
other non-proprietary information and IT systems such as the NASA
Integrated Enterprise Management Program and SAP R/3 Asset Management
system. As an example, consider the following question: What is the
impact to the supply base if the new Crew Exploration Vehicle Crew
Capsule is considered a non-repairable item? What is the repair cost
threshold associated with repair vs. buying new? What would be the
hardware obsolescence mitigation path and how much would be the cost?
These are questions best answered with a collaborated and data shared
approach with Program Office oversight.

One could argue the point of taking the CPFR process further and
integrating with the Defense Logistics Agency's emergent systems for
rapid mobilization of manufacturing sources or what they call the
Battlefield Backorder Breakout Initiative (B3I). B3I is a coalition of
Defense purchasing activities and Integrated Manufacturing Networks
(IMNs) that takes responsibility for determining best available solution
including engineering/technical evaluation, failure analysis and
production. This type of coalition, enabled by electronic data
interchange and/or secure Web-based systems, could add to NASA's Value
Chain and provide the visibility into such things as objective supplier
viability and supplier liquidity within the NASA product line while at
the same time, providing suppliers with advanced priority short-term
demand requirements by NASA.

**VI. Supplier and Product Line Viability**

Total or impending loss of a supplier or product line, to include
critical second tier sources, skill and/or raw material is due to a
number of factors such as change in ownership or business strategy,
decline in a companies financial liquidity, rapid change in product
technology, foreign competition, U.S. environmental regulations and
limited availability of raw materials. DMSMS or total loss of a supplier
is a serious and costly impact to sustaining any program and can impact
both the flight manifest and obligated Program Operating Plan budget due
to unforeseen and unusual economic stresses on a supplier. A supplier
solvency indicator could be expanded within the Earth-To-Orbit and
Interplanetary SCM simulation models and could give forewarning by
gathering and analyzing procurement data, opinion data, third-party
financial information (if available), in addition to collecting internal
logistics support analysis data e.g. Line Replaceable Unit Probability
of Sufficiency (LRUPOS), mean-time-between-failure, from the NASA
project elements. This data would be collected by a Program Office or
Agency SCM Center of Excellence. The result would be a collaboration of
strategic capabilities but primarily a financial stability indicator
model and supportability risk assessment of the supplier and subsystem.
For prime suppliers, the key issues are increasing shareholder value by
reducing excess manufacturing capacity, diversifying to global
commercial markets, and retaining a technological lead over competitors.
For sub-tier suppliers, the key challenge lies in sustaining design and
production capabilities for certain key subsystems and components in the
face of an increasingly shrinking market. However, designing an
operations architecture that allows for new technology insertion will
defuse the shrinking economic gains and diminishing marginal returns on
older hardware and designs. Avionics, specifically the microelectronics
are a good example of where "plug and play and throw away" works. Trying
to maintain components that have at best an 18 month product lifecycle
would be ludicrous. Hence, replace with a newer technology but one that
meets the performance and in usual cases, exceeds the performance
requirements. The culmination of this concept would be to provide NASA
and the contractors with a working retention strategy with a
standardized policy for daily monitoring of critical suppliers. The
question regarding "monitoring" the health of the supplier base, focuses
on the capability of all critical prime and sub-tier suppliers to
provide engineering data and expertise, hardware, and the associated
repair parts to adequately support the operational availability of the
designed system especially during periods of program transition. Loss of
a supplier is a serious issue for NASA and can impact sustainability of
all systems at all stages of the system lifecycle as well as the
obligated budgets due to unforeseen loss of a supplier.

Lessons learned to supplier viability:

**A. No one program or project can be responsible for maintaining the
industrial base for the entire agency. In this process the agency
could**;

1.  Establish a central Supply Chain Management center of excellence for
    all Agency programs

> 2\. Assess what level of supply base is critical for development.
>
> 3\. Establish a critical or preferred supplier pool for all NASA.
>
> 4\. Develop a strategy to encourage supplier consolidation to possibly
> include the DoD.

**B. Utilize phased new program development as a strategy for vendor
retention.**

1\. Evaluate and model program lifecycle maturity.

2\. Use new program development and timing to eliminate program
retention breaks.

3\. Map a new programs supplier list to existing NASA programs.

**C. Develop contracting strategies and contracting options to enable
consistencies in supplier contracts.**

1\. Act as liaison with major prime contract candidates ways to gain
synergies between programs and contracts.

**D. Identify key competencies and shortfalls to support emerging
technologies.**

The linear business as usual "push" manufacturing model vs. a 21st
Century demand-centric "pull" model that proactively manages demand and
uses stochastic optimization simulation methods for schedule variability
as reflected in the diagram below (Fig. 8). The intent is a constant
interplay between NASA and the suppliers. We can expect to:

1)  Reduce costs by reducing inventory requirements and making better
    use of assets

2)  Improve order fulfillment and on-time delivery

3)  Increase responsiveness due to the increased demand and supply
    information visibility

4)  Improve the ability to react to unplanned changes in demand.

![](media/image8.jpeg){width="5.819444444444445in"
height="4.364583333333333in"}

**Fig. 8: Present and Future state of Space Logistics**

The health of the supply base has an in-direct but significant
relationship to the quality of the final product, the reliability of
which is a factor in diminished potential market growth. That is,
variance in aerospace products, as they are severely modified for unique
uses, introduces reliability issues inversely proportional to the
quantities being supplied. Where quantities are few, especially as in
rocket engine/propulsion, power supplies, and mechanical system
components, exacerbated at a system level, the reliability that can be
expected diminishes rapidly. The aerospace response has traditionally
been to create organizational overhead layers, the purpose of which
often is to inspect what was not built in (to the product). A healthy
supply base, increasing production units through commonality throughout
aerospace applications, can offer improved reliability, eventually
leading to systems maturity that can lead to market growth as
competitors find a healthy supply base, with mature, better understood
components, from which to develop and explore new systems.

**VII. Standardization and Component Supplier Management**

A fundamental problem for most Logistics and Procurement Managers is
part number and procurement duplication. "Conservative estimates of
between 30% and 40% of a support contractors procurable spare parts are
duplicates or have acceptable substitutes. With the annual carrying cost
of between \$4,500 and \$23,000 per line item for the introduction of a
new part number, duplicate part proliferation is an area of known cost
exposure"[^9]*.* Compound the fact that NASA as well as the DoD have to
contend with Mil-Spec, Source Control Drawing and National Stock Number
schemes, the cost could be even higher. In a "stove-pipe" organizational
structure where the project offices act as independent agents, each part
in turn may be purchased from a different qualified supplier and stocked
with a different part numbering scheme. Not to mention the costs
associated with certifying multiple sources and redundant purchase
orders which will also result in poor asset utilization. "inaccurate
demand forecasting and supply planning means that manufacturers carry
excess inventory along their supply chain and suboptimize use of capital
assets like plant equipment."[^10] Simply stated, the results are -- too
many parts and too many suppliers. At the day-to-day operational level,
the cascading negative results include:

1)  Inhibiting parts standardization

2)  Discouraging design reuse

3)  Increasing material and holding inventory costs

4)  Creating excess / residual inventory

5)  Inflating purchasing administrative costs due to too many purchase
    orders for small quantities and too many suppliers

A common SCM architecture, to include Component Supplier Management
(CSM), reduces maverick buying and will not jeopardize the ability to
reduce operational recurring costs. CSM is advanced IT software
applications used for parts classification, standardization and
retrieval; as well as supplier (sourcing) management. Think of it as a
way to develop and manage the Bill of Materials (BoM) throughout the
system or program and product lifecycle. For a CSM system to operate in
NASA's quality driven environment, the application must provide instant
access to all partners in the Supply Chain and must also have the
following characteristics:

1)  Provide flexible part numbering classification schemes -- without
    requiring intensive conversion efforts to a common or fixed scheme

2)  Match the access and user needs of direct users, such as design
    engineering, procurement, logistics, and contracts.

3)  Interpret part information in real time in any format.

4)  Accommodate legacy parts data

5)  Support creation and maintenance of standardized parts descriptions

6)  Furnish data sheets on demand -- integrate with on-line catalog
    information sources where possible

7)  Supply multi-faceted analysis tools, including BoM unique/common
    parts analysis,; design cost impact in a "what if" simulation and
    evaluation of current part data base conditions

8)  Generic transactions to update BoM files

9)  Facilitate creation/maintenance of Preferred Parts List (PPL)

10) Integrate with application systems for CAD and Product Data
    Management (PDM). For decision support, supply chain information,
    such as inventory status from ERP and MRP systems must be readily
    available.

There are a number of cost benefits from implementing a CSM application
in a common SCM architecture but one of the most significant is reducing
duplicated parts and the costs associated with redundant sources of
supply, by this we mean the certification cost associated with those
suppliers and redundant contracting efforts.

**VIII. Conclusion and Recommendations**

The combination that has not existed before of awareness of NASA costs
by function, of supply chain practices, techniques and technology such
as simulation, and of the inter-relationships among factors that stretch
from product dependent factors, such as a new space transportation
system design, to supply chain system dependent factors, offers a
historical opportunity to dramatically improve the cost, responsiveness,
and safety/reliability for the Exploration task ahead of us.

Implementing a new practice within the Agency can be very difficult and
time consuming. It is even more difficult in this case since supply
chain is a new concept within the Agency, large number of supply chain
practices, over 500 best practices in the SCOR model, and supply chain
management requires cross-functional framework. Simulation -- SCOR best
practices -- logistics support. Agency-wide SCM Solution -- how do we
get there from here? A five step process to implementing a SCM policy.

[Step 1]{.underline} Make the business case. Evaluate sustainment and
operational requirements and compare to existing processes and validate
the change as value added to the Agency. Make the Sale to Suppliers.
First comes the hard part. Supply chain automation is uniquely difficult
because its complexity extends beyond the Agency and Contractor walls.
We will need to change the way we work and so will the people from each
supplier that we add to our network.

[Step 2]{.underline}. Evaluate the financial and operational value to be
achieved in terms of financial performance and operational performance
characteristics such as cycle time, quality and service level
attainment. Use modeling tools to simulate end-state financial
statements and operational performance criteria. Wean the Employees off
the Phone, Fax and email. Selling a supply chain concept is difficult on
the outside and it isn\'t much easier inside. Operations people are
accustomed to dealing with meetings, phone calls and work authorization
documents and will most likely want to keep it that way. If we can\'t
convince people that using the SAP R/3 software will be worth their
time, they will easily find ways to work around it. ERP at least erases
the old ways of working by blotting out legacy software systems. Supply
chain software is less militant. We cannot disconnect the telephones and
fax machines just because we have a supply chain application in place.

[Step 3]{.underline} Prepare for Bad Information. ---At First there is a
diabolical twist to the quest for supply chain process acceptance among
the industry. New supply chain systems process data as they are
programmed to do, but the technology cannot absorb the Agency's or
contractor\'s history and processes in the first few months after an
implementation. IEMP forecasters and planners need to understand that
the first bits of information they get from a system might need some
tweaking. If they are not warned about the system\'s initial naiveté,
they will think it is useless.

[Step 4]{.underline} Make and enable the Supply Chain Connection to ERP
project. You have probably heard that installing supply chain software
is the natural next step after finishing an ERP project. Indeed, the two
serve each other well. ERP captures all the product, finance and asset
inventory information that supply chain applications need to predict
demand and optimize the flow of material and information through the
chain. Unfortunately, that symbiotic relationship does not translate
into an easy integration between the two different systems. In all
likelihood, our new IEMP AM (asset management) implementation will not
interface cleanly with other current ERP systems.

[Step 5]{.underline} Enhance cross functional activity by defusing
functional warfare within the NASA culture. Supply chain software
projects bring CIO's and CFO's into direct conflict with the people who
run the PP&E day to day.

In addition to these steps, we can also begin to formulate a supply
chain vision and strategy based on organizational aptitude and enabling
technologies. "This strategy should include the following key steps;

[Step 6]{.underline} Identify the Agency's core supply chain
differentiators and capabilities, and assess current performance.

[Step 7]{.underline} Determine which functions could be better performed
by a partner, and begin to identify these partners.

[Step 8]{.underline} Define the supply chain process components and the
needs for organizational reconstruction.

[Step 9]{.underline} Define the measurement framework, which is aligned
with business objectives and goals. Set targets and thresholds for the
key supply chain performance indicators.

[Step 10]{.underline} Define the real time information and connectivity
vision, including an open- and-service-based technology architecture,
required to support the vision".[^11]

The Agency must be able to support multiple types of simultaneous
activities. "Aerospace firms must become proficient at service execution
and spare parts fulfillment. ...Companies need to augment ERP in areas
such as sophisticated spare-parts planning, complex overhaul operations,
technical documentation and automated condition monitoring."[^12] "A
supply chain initiative should be pursued to better understand
opportunities and define better ways of doing business. Such an
initiative should be based on established Business Process Reengineering
(BPR) and IT that are widely employed in the private sector.
Improvements in SCM would address the areas and the interactions among
Integrated Logistics Concepts, material and information flows,
requirements management systems, work control and verification, ground
process scheduling, program-level manifesting, corrective action
systems, improvement systems, data management systems, sustaining and
technical support, procurement and financial systems. Together, BPR and
IT advances and an improved integration of the host of other common
network operations and enabling functions, an initiative looking across
all supply chain functions, may offer significant opportunities for
improvement that must be quantified and defined."[^13] As we stated
earlier, applying the high-volume, consumer demand driven SCM
disciplines of the commercial industry to a low-volume, schedule and
quality driven Aerospace environment is also vital based on two simple
words - human mortality. A schedule delay with today's Space Shuttle
Program simply means increased day-to-day cost and that launch would be
scrubbed for the day to try again at the next launch window. Schedule
delays with a Lunar or Mars Outpost could mean a catastrophic life event
based on the fact that at this point in time, there are basic human
needs we must source from Earth e.g. water, oxygen, food and they must
be delivered -- on time, every time! This becomes especially crucial as
human exploration moves further from Low-Earth-Orbit, as with the
current Space Station, to operating logistics nodes that are Lunar based
and beyond.

**References**

[^1]: Supply Chain / DMSMS Specialist, Space Shuttle Program Office,
    John F. Kennedy Space Center/MK-SSO

[^2]: Technical Manager, Engineering Development Directorate, Systems
    Engineering and Integration Office, John F. Kennedy Space
    Center/DX-C

[^3]: Technical Manager, Engineering Development Directorate, Systems
    Engineering and Integration Office, John F. Kennedy Space
    Center/DX-C

[^4]: Assistant Professor, Aeronautics and Astronautics and Engineering
    Systems Division, Massachusetts Institute of Technology

[^5]: Murphy, Charlie, Sealing, Scott, *"Supply Chain Management and
    Integrated Logistics Support Considerations for Exploration,"*
    United Space Alliance, May 2004

[^6]: Ellram, Lisa M. and Martha C. Cooper, *"Supply Chain Management,
    Partnership, and the Shipper -- Third Party Relationship,"* The
    International Journal of Logistics Management, Vol. 1 No. 2 (1990),
    pp. 1-10.

[^7]: O. de Weck and D. Simchi-Levi, "Haughton-Mars Project Expedition
    2005", Final Report, MIT, NASA Kennedy Space Center, NASA Report
    NASA/TP-2006-214196, January 2006

[^8]: E. Gralla, S. Shull, O.de Weck, G. Lee and R. Shishko, "A Modeling
    Framework for Interplanetary Supply Chains", AIAA-2006-7229, Space
    2006, September 19-21, 2006

[^9]: Aberdeen Group,*"Component & Supplier Management: Saving Time and
    Money Part by Part,"URL:*
    [http://www.i2.com/assets/pdf/PDS_csm_v61_pds7203_0404.pdf#search=%22%E2%80%9CComponent%20%26%20Supplier%20Management%3A%20Saving%20Time%20and%20Money%20Part%20by%20Part%2C%E2%80%9D%20Aberdeen%20Group%2C%20%22]{.underline}
    Cited March, 2002

[^10]: Radjou, Navi, *"The Defense Contractors' Supply Chain
    Imperative,"* Forrester Research Brief Series, URL:
    [http://www.forrester.com/ER/Research/Brief/Excerpt/0,1317,16196,00.html]{.underline}
    Cited August, 2003

[^11]: Lavacca, John, Bunyan, John and Cross, Gary, IBM Business
    Consulting Services *"Transforming your supply chain to on
    demand**:** Competitive advantage or competitive necessity?**,"***
    URL:
    [http://www-1.ibm.com/services/us/index.wss/ibvstudy/imc/a1000510?cntxtId=a1000065]{.underline}
    Cited March, 2003

[^12]: Bob Parker, AMR Research,. *"Aerospace and Defense Industry.
    Outlook: Lifecycle Value Stream. Must Drive IT Investment*,", URL:
    [http://www.sap.com/industries/aero-defense/pdf/BWP_SAP_A&D_Maint_Repair_Overhaul.pdf#search=%22Aerospace%20and%20Defense%20Industry%20Outlook%3A%20Lifecycle%20Value%20Stream%20Must%20Drive%20IT%20Investment%2C%E2%80%9D%20AMR%20Research%20%22]{.underline}
    August 16, 2004

[^13]: Stanley, Doug, NASA. *"Exploration Systems Architecture Study
    (ESAS) Final Report,"* URL:
    http://www.nasa.gov/mission_pages/exploration/news/ESAS_report.html
    Cited July, 2005