Space Systems Engineering And Operations - Appunti

SERVICE MODULE

feeds into

PAYLOAD

SPACE SEGMENT

SPACE SYSTEM

it answers a specific fact

GROUND SEGMENT

Receive and send data to SCL

GROUND STATIONS

elaborates the data

CONTROL CENTERS

SYSTEM Design

SYSTEM Implementation

SYSTEM Management

realization of the segments

in-flight operations

Concurrent Design Facility

Every subsystem designed

IN PARALLEL

MISSION OPERATION CENTERS

SERVICE MODULE

SCIENCE OPERATION CENTERS

PAYLOAD

After TRL=3 it needs 2 years from one level to the other.

TRL 1 - Conceptual idea and basic purpose

> Flight proven system in successful operation

TRL 3 - Proof of concept > active research, development, analysis & laboratory studies answers performances

TRL 4 - BREADBOARD > Simplified hardware

doesn't answer standards of space environment

BRASSBOARD - medium fidelity functional unit

in a simulated environment operational uses as much operational HW/SW as possible

needed before launch with basic technological components

TRL 5 - Low fidelity unit

commercial or/and ad hoc components

can focus only on one functional unit

TRL 6 - Representative model or PROTOTYPE tested in relevant environments

Prototype

form, fit & function of flight unit at a scale deemed to be representative of the final product operating in its operational environment.

Engineering Unit

High fidelity unit that demonstrates the critical aspects of the equipment/process involved in the development of the operational unit. Closely resembles (HW/SW) the final product.

Qualification Unit

Identical to the flight unit but heavily tested (doesn’t fly).

Protoflight Unit

Limited qualification tests. It will fly.

Flight Unit

End product. It’ll undergo acceptance level testing.

• TRL 7 — prototype demonstrated in space environment
• TRL 8 — flight qualified (test and demonstration)
• TRL 9 — flight proven

TRL also for software!

Breadboard → prototype 5 months

6^th level needed. On board/ground stations

• Product release α = ALPHA → Most functionalities implemented
• β = BETA → Implementation of complete SW functionality

Ready for use in an operational/production context.

TRL 5/6/7 are different in ESA and ISO scale.

CONCEPTUAL OPERATIONS

consequential dependence between functionalities

put in sequence and with an assigned DURATION

• ground rules
• Mission operations control
• How data are exchanged on the ground

mapping the functionalities and who's doing what

PHASES

happens only ONCE in the mission (e.g. launch)

MODES

activities put together that happen more than once

no "optimal" solution exists for simple problems

CRITERIA

• quantities defined as relevant
• for addressing decisions and ranking the different options

whenever we have a bifurcation btw different possibilities

Typical cost and performance criteria are the "BUDGETS"

• mass
• power
• CD
• pointing
• time
• cost
• risk assessment
• mission specific budgets
• system acquisition cost
• operations and support cost
• disposal cost

depend on the specific mission - e.g. cost and TOF may be more relevant for commercial missions

system effectiveness -> output

desirable level -> RISK, COST, PERFORMANCE

When a final baseline to study has been chosen

• Best in terms of
  • mission
  • SIS
  • space segment
  • ground segment

Typical trade-offs

• CUSTOM vs OFF-THE-SHELF?
• AUTONOMOUS or NOT?
• FREQUENCY for COMMS
• LEVEL OF REDUNDANCY
  • e.g. 3 pc for a space shuttle
  • SW
  • HW
  • ARCHITECTURE
• Depends on the TRL also
• LONG LIFE - SINGLE UNIT or SHORT LIFE - MULTIPLE UNITS?
  • More resistant S/C are needed, but only once
  • Less resistant, but more launches needed over a longer time span
• SINGLE S/C vs CONSTELLATION?

Trade-offs also during operational phase!

DESIGN

REUSABILITY

• New designed to be reused in the future
• Undersigns to maximize the use of existing products
• To MAKE or TO BUY?
  • First option, otherwise modification of existing SIS, otherwise
  • SPECIFIED for each component on the product tree

3) Demonstration

observing and recording FUNCTIONAL OPERATION

QUALITATIVE

• without elaborate instrumentation, special test equipment or quantitative evaluation of data.

In general verifies system characteristics such as

• human engineering features
• services
• access features
• transportability

e.g. verify we can access the pc to load batteries

by OPERATION ADJUSTMENT or RECONFIGURATION of a test article.

* ROD = Review of Deign

4) Tests

using SPECIAL EQUIPMENT

• instrumentation
• simulation techniques

to determine compliance with

the requirements of a system and its components

on established principles and procedures,

to verify possible failures not considered before

under a limited set of CONTROLLED CONDITIONS

QUANTITATIVE

Performed at any level of assembly.

Data to be ANALYSED (do not confuse with point 4)

Must not be done in the final phase!

They're STANDARDIZED. Dependent on the environment.

PREFERRED METHOD used where:

1. Analytical techniques do not produce adequate results
2. Failure modes exist
3. For any component directly associated with CRITICAL SYSTEM interfaces

e.g. tests for -> different TEST FACILITIES to be used (bottom - up)

• compressing -> ERA compatibility
• structural loads
• combustions & shock
• vacuum
• of. functions bought from suppliers -> already qualified

We also have:

• ORR → operational readiness review
• FRR → flight readiness review
• LRR → launch readiness review
• FQR → flight qualification review
• EOLR → end of life review

Partioning a project into phases (major contribution to risk management)

All projects are broken down into phases

• Phase designed to advance the system from one baseline to another
• At the end of phases (mostly) → project reviews as MILESTONES

Life Cycle Models

• Performed by team not responsible for the activities covered by the review

Reviews aim at helping to:

1. Assess the validity of output elements in relation with regs/expectations
2. Decide to start the next phase

Depend on the typical application:

• Solution development approach
• Timeline for deployment
• Status of reps
• Risk sensitivity/complexity of the system
• Stability of the environment