Space Engineering:

1
Space Engineering A World of DifferenceIr. A.
Kamp a.kamp_at_lr.tudelft.nlhttp//as.lr.tudelft.nl
Delft University of TechnologyAstrodynamics
Satellite Systems
2
Space Remoteness from Earth

• Our familiarity with
• Protective Earth atmosphere
• 1-G environment
• Accessibility for repair/inspection
• Is partly lost in Space Engineering

3
What Makes It So Different?

• Space different and strange environment
• Demanding performance requirements
• Complex systems
• Multidisciplinary
• Severe safety
• High availability
• Many interfacing parties

4
Top ClassComplexity, Safety, Availability,
Interfaces
5
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
• gt100-200
• Time required from initial conception till
  operation
• 3-10 years

Ref AE1-801 SET I
6
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

7
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
• Its different!

8
Space Difficult To Get In

• Severe launch loads

Antenna
Acoustic loads
box
Random loads
LVA
Steady State SinusShock loads
9
Dimensioning Instruments, Electronic Boxes, Etc
Size your equipment to withstand the static load
factors and the severe random vibrations
60
5
10
Mechanical Engineering

• In-depth analysis
• Stress
• Dynamic and Acoustic
• Thermal distortion
• Fatigue
• Micro-vibration
• Mass budgeting
• Structural testing(random vibrations, acoustic,
  shocks)

11
Space Environment

• Kind
• No water vapour
• No wind
• Very clean environment
• Zero effective gravity

• Hostile
• Hot and cold
• Very high vacuum
• Atomic oxygen
• High energy electromagnetic radiation
• Particle radiation
• Debris

12
Hot and Cold

• Solar flux densityon earth 500 W/m2 in space
  1400 W/m2
• Earth surface 293 K cold space 4 K
• No convection

13
Hot and Cold

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

14
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

15
ENVISAT Thermal Protection

• Thermal blankets
• Superior insulation
• Radiators
• Rejection of heat

16
ENVISAT Thermal Protection

• S/C bottom
• battery compartment inside view

17
ENVISAT Thermal Protection

• S/C bottom
• battery compartment radiator surfaces

18
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

19
High Vacuum

• Immediately life threatening
• Engines have to carry fuel and oxidizer
• Risk of cold welding
• Risk of inadvertent pressure vessels

20
Still Atmospheric Drag
21
Atmospheric Drag Cleans Up
22
High Vacuum Contaminating?

• Sublimation of materials (outgassing)
• Contaminants deposit on sensitive surfaces
• UV radiation leads to polymerisation of organic
  molecules

23
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 _at_ 80 C in vacuum
• Contamination Budget Analysis
• Contamination monitoring and control during AIT

24
Thinking Clean, Working Clean
SCIAMACHY optical instrument integration in Clean
Room 100 conditions
25
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 grounddesign for testability!

26
Solar Array Deployment Test
Test Engineering
27
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?

28
OMI Instrument Proton Shielding

• Concept without and with shielding

Ref Dutch Space OMI PSR Sep 2002
29
Diversity of Requirements
30
Managing Risk of Failures

• Ensure projects 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
  StandardizationECSS-E-20A Electrical and
  Electronic
• www.ecss.nl

31
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 first
• First time right!

32
High Speed Line Tunnel Drilling

• Complex systems, Multidisciplinary, Safety,
• Many interfacing parties

33
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

34
Space System Development Flow
Systems Engineering flow in time

• Requirements discovery
• Development philophy
• Cost break-down
• Resource budgeting
• Risk map

Requirements flow-down and traceability Design
options trade-offs Verification planning
35
Space System Development Flow
In depth
36
Spacecraft Subsystems
Guidance, Navigation Control
Computer Data Handling
37
Wrap-Up Space Engineering

• Challenging functions performance
• For a very different environment
• Involving many (special) disciplines
• Systems Engineering approach to do the first
  things first and do it the first time right
• Based on requirements
• Structured and controlled
• Space engineering is done with numbers
• In-depth analysis, testing, tracking,
  documentation

38

39
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)