The Department of Defense (DoD) established the Modular

Open Systems Approach (MOSA) for procuring new systems

and upgrading existing systems. This approach is designed to

reduce acquisition and sustainment costs without sacri�cing

capability, and it is mandatory* for all DoD e�orts. The Space

Dynamics Laboratory (SDL) has the experience and the services

to help your agency integrate complex modular open systems.

*http://www.acq.osd.mil/se/initiatives/init_osa.html

SDL SERVICES

SDL is one of 14 University A�liated Research Centers (UARC), a

status that provides:

• Independence & objectivity

• Current operational experience

• Freedom from real and/or perceived conflicts of interest

As a trusted Government partner, SDL has had great success

facilitating and integrating MOSA in such programs as Space

Plug-and-play Architecture and Modular Open Network

ARCHitecture (SPA/MONARCH), Standard Network Adapter for

Payloads (SNAP), Modular Space Vehicle (MSV), Operationally

Responsive Space 2 (ORS2), Flexible Weapons (FLEX), and

Distributed Common Ground System (DCGS).

BENEFITS OF USING MOSA

MODULAR OPEN SYSTEMS APPROACH SERVICES

SDL/14-639A

1695 North Research Park Way • North Logan, Utah 84341 • info@sdl.usu.edu • www.sdl.usu.edu

S P A C E D Y N A M I C S L A B O R A T O R Y

REDUCED ACQUISITION &

SUSTAINMENT COSTS,NO CAPABILITY

SACRIFICE

Component Reuse

Facilitate Competition & Innovation

Incremental Capability Enhancement

Increased Ability to Upgrade

Resiliency to Requirement Changes

Enhanced Parallel Development

MOSA’S MODULAR DESIGN SAVES TIME & MONEY

Initial Cost

Integration Cost

Follow-on Cost

Reuse

Vendor-lock

Flexibility

TRADITIONALIMPLEMENTATION MOSA

LOW HIGH LOW HIGH

MOSA COST SAVINGS

By decoupling system components, MOSA provides cost savings

in the following ways:

• Reduces interface definition & design effort by using

standard interfaces

• Facilitates parallel development of hardware & software

• Reduces testing effort by consolidating changes

• Reduces system integration effort by allowing for individual

component verification

Using packet encapsulation minimizes change propagation. The carrier can change, but the packet remains the same.

01011

01100

10101

11110

01001

10110

TransportationModel

Data Model

01011

01100

10101

11110

01001

10110

OSI ModelApplication

Network process to application

PresentationData representation,

encryption, conversion

SessionInterhost communication,

session management

TransportEnd-to-end connections,

reliability, flow control

NetworkPath determination &

logical addressing

Data LinkPhysical addressing

PhysicalMedia, signal &

binary transmission

SPA Model

SPA Components

SPA Application Framework

xTEDS Interface

SPA Network

SSM

SPA Subnets

Ethernet, SpaceWire,I2C, USB, Serial

Hos

t Lay

ers

Med

ia L

ayer

s

Enables transport via truck, train, ship, plane, etc.

Enables transport via any data

protocol

1695 North Research Park Way • North Logan, Utah 84341 • info@sdl.usu.edu • www.sdl.usu.edu

OPEN STANDARDS

• Available to everyone

• Still interoperable with

proprietary solutions

• Developed & maintained

by the community

• Provider or implementation agnostic

• Allow for enhanced competitive

solutions

• Open to improvement through a

well-managed process

LAYERED ARCHITECTURE

• Network conceptual model uses

layered architecture

• Layers are developed independently

• Individual layers improve maintain-

ability & enable layer modification

with minimal impact

• Layer boundaries provide ideal

testability

• Simple architecture for ease of use

HARDWARE INDEPENDENT

• Portable Operating System Interface

constructs (POSIX & POSIX-like)

• Platform Abstraction Layer (PAL)

- Provides standardized application

programming interface (API) to the

operating system & hardware

- Localizes hardware-dependent code

in a single layer

- Allows for hardware & OS

modifications without impacting the

application code

- Enables quick & easy code

development for multiple software

or hardware platforms

NET-CENTRIC IMPLEMENTATION

• System of systems

- Communicates across heterogeneous

network media via packet encapsulation

- Abstracts complex interfaces into simple

network-accessible services

- Enables communication between systems

not originally designed to interoperate

- Uses logical addressing to ignore physical

location of components

- Enables dynamic discovery of available

network services

S O F T W A R E F O R C O M P L E X M O D U L A R O P E N S Y S T E M S