1. Satellite & Data Communication for Air Cadets
12/09/2019
Satellite & Data Communication for Air Cadets
Briefing pack provided by SO2 Space, AWC Cranwell.
Unit 19
Unit Code:F/503/2045
Credit Value: 5
Guided Learning Hours: 40
“Our dependence [on space] has never been higher. In fact, it’s integrated into how we fight wars today so deeply that it is hard to imagine taking space out of the equation.”
Gen William L Shelton, CinC USAF Space Command
Speech to U.S. National Space Symposium, 12 Apr 11 1

2. 12/09/2019
Unit Aim
The aim of this unit is to give learners knowledge of satellite and data communication systems and networks for Air Cadets.
CLASSIFICATION
UNCLASSIFIED

3. 12/09/2019
Unit Introduction
This unit gives learners knowledge of satellite and data communication systems and networks that are required at ATC Senior and Master Air Cadet level.
This unit introduces the principles and equipment used in satellite and data communication. It explores the types, orbits and roles and construction of satellites, and describes the basic function of a Global Positioning System.
The unit also develops an understanding of types of data communications networks and mobile communication. 3

4. Learning Outcomes On completion of this unit a learner should:
Know main types and roles of satellites and principles of earth orbit.
Know components and principles of a Global Positioning System
Know principles of data communication
Know types and roles of mobile communication

5. 12/09/2019
UK Space Primer
This document should be used as the reference for these slides. It will provide explanations and examples for the subject area.

6. Scope The Space Environment Orbits Launch
12/09/2019
Scope
The Space Environment
Orbits
Launch
The Global Positioning System
The Principles of Data Communication
The Types & Roles of Mobile Communication
Summary
Questions

7. Reference: Chapter 1; UK Space Primer
The Space Environment
Reference:
Chapter 1; UK Space Primer 7

8. Space Characteristics
No geographical boundaries
Freedom of movement
Unique characteristics
No geographical Boundaries: Every country has the right to access Space. No country can claim it as their own.
Freedom of Movement: A satellite on orbit can cross over any country (depending on the orbit of course) with freedom of movement. The same is not true of an aircraft, it must have permission. For military aircraft this is problematic (use U2 and Gary Powers as an example).
Unique characteristics: In space, spacecraft follow the Laws of Kepler not the aerodynamic principles of Bernoulli.

9. The Boundary Between Air & Space
150km
Spacecraft in orbit
100km
Limit of aerodynamic control
80km
US Definition
150
100 80 9

10. The Space Environment An environment characterised by:
High energy particles
Fluctuating magnetic fields
Variable temperatures
No aerodynamic forces
The laws of orbital motion 10

11. Key Environmental Regions
Magnetosphere
Exosphere
Thermosphere
Ionosphere
Mesosphere
Stratosphere
Space Weather
Troposphere
Terrestrial Weather 11

12. Orbits - Definition of Terms

13. Apogee and Perigee Apogee Perigee Furthest point from Earth
Closest point to Earth

14. Ground Trace
A ground trace is the projection of a satellite’s 3D orbit onto the earth’s surface as a 2D representation
Nadir = point directly underneath the satellite. Therefore a grd trace is a track of the Nadir of the satellite.

15. Common Orbits HEO MEO GEO LEO Orbit size determines time for one orbit
~800-40,000 km
11 HRS 58 MIN
~26,000-8,000 KPH
Common Orbits
Orbit size determines time for one orbit
Orbit size and shape also determines the speed
GEO
HEO
MEO
Earth NOT to scale !
LEO
Further away from centre of Earth = less gravitational pull therefore less centri-pedal force therefore less speed required to maintain orbit.
1st Key Point: Orbital period is dependant on height above Earth
So what for speed? Kinetic energy and velocity and problem of debris/size.
Use White Board. Put up KE equation.
2nd Key Point: ½ mass multiplied by velocity squared = formula for calculating the kinetic energy of a body.
Use this to explain how small objects in space pose threat due to high velocities involved.
850 km
101 MINUTES
24,600 KPH
~20,830 km
11 HRS 58 MIN
~14,330 KPH
~36,160 km
23 HRS 56 MIN
~11,160 KPH