Space Electronics Symposium October 3, 2002 Space Engineering: A World Of Difference 1 Ir. A. Kamp Space Engineering: A World of Difference Ir. A. Kamp

Space Electronics Symposium October 3, 2002

Space Engineering: A World Of Difference 1

Ir. A. Kamp

Space Engineering: A World of Difference

Ir. A. Kamp [email protected]://as.lr.tudelft.nl

Delft University of TechnologyAstrodynamics & Satellite Systems



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Space = Remoteness from Earth

Our familiarity with Protective Earth

atmosphere 1-G environment Accessibility for

repair/inspection

Is partly lost in Space Engineering



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What Makes It So Different? Space: different and “strange”

environment Demanding performance

requirements Complex systems Multidisciplinary Severe safety High availability Many interfacing parties



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Top ClassComplexity, Safety, Availability, Interfaces



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Complex and High Cost Systems

Cost per kg INTELSAT: development & launch

250,000 €/kg in-orbit mass ISS: 450,000 €/kg Globalstar: 50,000 €/kg Mid-sized car: 25 €/kg

Number of personnel involved in development >100-200

Time required from initial conception till operation 3-10 years Ref: AE1-801 SE&T I



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Objective of Presentation

How “strange” is the Space Environment?

Some of the impact on engineering

How are space systems developed?to minimise development risk and risk of failure



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What Is Space?

It is difficult to get to and to stay in

A completely unforgiving environment If you screw up the engineering,

SOMEBODY DIES! A very hostile environment

It’s different!



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Space: Difficult To Get In Severe launch

loads

LVA

Antenna

box

Steady State SinusShock loads

Acoustic loads

Random loads



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Dimensioning Instruments, Electronic Boxes, Etc

Load factors

10

100

1 10 100

Mass in kg

Load

fact

or in

g

Size your equipment to withstand the static load factors and the severe random vibrations

60

5



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Mechanical Engineering In-depth analysis

Stress Dynamic and Acoustic Thermal distortion Fatigue Micro-vibration Mass budgeting

Structural testing(random vibrations, acoustic, shocks)



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Space Environment Hostile

Hot and cold Very high

vacuum Atomic oxygen High energy

electromagnetic radiation

Particle radiation Debris

Kind No water vapour No wind Very clean

environment Zero effective

gravity



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Hot and Cold

Solar flux density:on earth 500 W/m2 in space 1400 W/m2

Earth surface 293 K cold space 4 K

No convection



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Hot and Cold

Without special measures material temperatures in earth orbitmay vary between –270 and +130 C



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Good Performance Only If

Narrow temperature ranges Electronics typically –10/ + 40

C Batteries - 5/ + 15 Hydrazine fuel + 9/ + 40

Limited thermal gradients

Adequate thermal stability



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ENVISAT Thermal Protection

Thermal blanketsSuperior insulation

RadiatorsRejection of heat



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Thermal Engineering Design analysis

Thermal testing in vacuum/solar sim. Verify the predicted

temperature extremes Verify proper

functioning of equipment under TV conditions

After thermal cycling At Textreme



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High Vacuum

Immediately life threatening

Engines have to carry fuel and oxidizer

Risk of “cold welding” Risk of inadvertent pressure vessels



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Still: Atmospheric Drag



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Atmospheric Drag Cleans Up



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High Vacuum: Contaminating?

Sublimation of materials (outgassing)

Contaminants deposit on sensitive surfaces

UV radiation leads to polymerisation of organic molecules



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Cleanliness Engineering Material selection

No Cadmium, Zinc, Magnesium, plastics Only special adhesives, and lubricants for

mechanisms

Outbaking of volatile materials, all equipment Typ. 3 days @ 80 C in vacuum

Contamination Budget Analysis Contamination monitoring and control during

AIT



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Thinking Clean, Working Clean

SCIAMACHY optical instrument integration in Clean Room 100 conditions



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Effective Absence of Gravity

An advantage or a disadvantage? What happens to an astronaut when he

swings a hammer and hits the nail? Where is my liquid propellant in the tank?

Structures designed for weightlessness may not be testable on ground:design for testability!



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Solar Array Deployment Test

Test Engineering



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Solar and Cosmic Radiation

Flying through a plasma of charged particles (protons, electrons, heavier ionized atoms)

Typ. 450 km/s

How to shield or harden your electronics design?

What about static charging?



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OMI Instrument Proton Shielding

Concept without and with shielding

Ref: Dutch Space OMI PSR Sep 2002



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Diversity of Requirements

EnvironmentFunction andPerformance

Interfaces

Space Mission

Standards



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Managing Risk of Failures Ensure project’s conservative approach Track weaknesses found in the design

analysis, manufacturing, test and operations RAMS Engineering

Standardisation of design and development ECSS: European Cooperation for Space Standardization

ECSS-E-20A Electrical and Electronic

www.ecss.nl



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Need for Systematic Approach

High complexity, high development risk Little time to iterate No chance to inspect or repair in orbit Aiming for near-absolute reliability!

Systems Engineering:First things firstFirst time right!



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High Speed Line Tunnel Drilling

Complex systems, Multidisciplinary, Safety,Many interfacing parties



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Systems Engineering Method

Structured development process User requirements driven Timely integration of all disciplines Well motivated choices between all

options Visibility/traceability Control With the end product always in mind



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Space System Development Flow

Requirements discoveryDevelopment philophyCost break-downResource budgetingRisk map

Systems Engineering flow in time:

Requirements flow-down and traceability

Design options trade-offsVerification planning



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Space System Development Flow

In depth:



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Spacecraft SubsystemsSpacecraft

S/C BusPayload

Propulsion

Electrical Power

Thermal Control

Structure

Telemetry &

Commands

Communication

PropulsionRemote Sensing

Meteorology

……….

Guidance, Navigation & Control

Computer & Data Handling



Ir. A. Kamp



Ir. A. Kamp

Web Links Used

http://www.esa.int and http://envisat.esa.int (sheets 8,10,13,15,16,17)

www.delftaerospace.com (sheets 8,9,26) http://seds.lpl.arizona.edu/nineplanets (sheet 12) http://www.ee.surrey.ac.uk (sheet 14) http://science.nasa.gov/ (sheets 20,21) www.dutchspace.nl (sheet 22,24) http://www-istp.gsfc.nasa.gov/Education (sheet 27) www.ecss.nl (sheet 29) www.highspeed.nl (sheet 31) www.loesje.org (sheet 37)

Documents

Space Electronics Symposium October 3, 2002 Space Engineering: A World Of Difference 1 Ir. A. Kamp Space Engineering: A World of Difference Ir. A. Kamp