1. The EmDrive - A New concept in Spacecraft Propulsion
Roger Shawyer C.Eng MIET FRAeS
SPR Ltd September 2008
SPR Ltd

2. HOTBIRD 2 Launch (Nov 1996) Total vehicle mass at launch 204 tonnes
Satellite mass on station 1.3 tonnes
Majority of mass lost is reaction mass
SPR Ltd

3. EmDrive EmDrive is the first technology to provide
direct conversion of
electrical energy to
thrust, without the need
for reaction mass, and
without contravening the
laws of physics
Prototype C Band Thruster
SPR Ltd

4. Why Launch satellites? Fear Military applications e.g. NATO 1VB
Greed Commercial applications e.g. HOTBIRD 2
Curiosity Scientific missions e.g. SMART 1
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5. Benefits of Propulsion without reaction mass
Military Increase in manoeuvrability
No residual propellant limitation
Commercial - Lower launch costs
Longer operating lifetime
Scientific Shorter mission times
Larger payloads
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6. Principle of Operation
Electromagnetic waves carry momentum
Newton’s 2nd Law
Force = Rate of change of momentum
Radiation pressure proportional to propagation velocity
Propagation velocity dependent on Waveguide geometry
Waveguide resonant at input frequency
Force difference multiplied by Q
Einstein’s Law of Special Relativity
EM wave and waveguide have different frames of reference
EmDrive is an Open System
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7. Production of net thrust
Area A1
Area A3
Area A2
At cut off diameter,velocity is zero, F2 is zero, but A2 is clearly not zero.
Sidewall thrust F3 does not equal F1
A net force in the direction of F1 is produced
Propagation velocity has a highly non linear relationship with waveguide diameter
SPR Ltd

8. Conservation of Momentum
Reaction Force
F=Ma
Thrust
T=Q(F1-F2) F2 F1
Total Momentum gained by thruster =Q x Momentum lost by EM wave at each reflection
Mechanical reaction occurs between thruster end plates and EM wave
Electrical reaction occurs as input impedance changes with acceleration
EmDrive is a true electrical machine
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9. Conservation of Energy
Q = Stored energy/energy lost per cycle
Acceleration extracts stored energy from the thruster
Thus acceleration reduces Q
Loss of Q increases with average velocity
Effect of increased Q
For Q= 5x104 (1st generation EmDrive)
Static specific thrust =315mN/kW
Specific thrust at 3 km/s = 200mN/kw
For Q = 5x (superconducting)
Static specific thrust = 31.5 kN/kW
Specific thrust at 0.1 m/s = 8.8 kN/kW
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10. Experimental Programme
DTI SMART Award Experimental Thruster
Proof of Concept
DTI R&D Grant awarded Demonstrator Engine
Demonstrator Engine tests complete
Superconducting Thruster tests start
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11. Experimental Thruster Demonstrator Engine ( 2002) (2006)
Static specific thrust = 19mN/kW Static specific thrust = 214mN/kW
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12. Measurement methods
Design software verified by small signal measurement of frequency and Q
Static Thrust measured in Vertical Up,Vertical Down and Horizontal configurations
Proof of concept test programme eliminated all proposed spurious force mechanisms
Pulse tests proved momentum exchange
Thrust, Power and Temperature data recorded for each test run
All measurement parameters regularly calibrated
Test rigs subject to EMC testing
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13. Dynamic Test Rig (2007)
Acceleration of 100kg beam supported on air bearing to 2 cm/s
Dynamic specific thrust = 287mN/kW
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14. Dynamic Test Programme
Direction of acceleration confirms that EmDrive obeys Newtons Laws
EmDrive is not a reactionless machine
Input power telemetry confirms electrical reaction during acceleration
Acceleration only starts as input frequency locks to resonant frequency
Programme included acceleration and deceleration runs in both directions
Calibration to determine friction torque carried out prior to each test run
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15. SPR Ltd

16. Typical Commsat Application
3 tonne GEO communications satellite contains 1.7 tonnes of propellant
Launch mass reduced to 1.3 tonnes
Cost savings £15 billion for GEO launches planned for next 10 years
Deployment of solar arrays and antennas in LEO
Spiral trajectory (Edelbaum transfer) to GEO in 36 days
Operational life no longer restricted by propellant reserves
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17. Science Mission Applications
Comparison with SNECMA PPS1350 system performance for ESA SMART 1 Luna Probe mission
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18. The Future Large geostationary communications satellites
- In orbit mass > 20 tonnes
- Global mobile telephone system capability
- Will replace terrestrial mobile phone systems
Solar Power Satellites
- LEO to GEO transfer using EmDrive engines operating at
downlink frequency
- EmDrive is an enabling technology for SPS
- Provides a secure green solution to the global energy problem
Manned Mars missions Solar powered UHF EmDrive engines
- Short flight times (41 days)
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19. Second Generation Engines
Superconducting technology can give thrust increase x 105
Superconducting cavities in production for high energy physics experiments
e.g. Q=2x109 for LHC at CERN and 5x109 for TESLA test facility
Engine used for static thrust space applications e.g.asteroid deflection
- Thrust orthogonal to asteroid velocity
- 1 kW second generation engine
- Nuclear power source 24 kW
- 1 Km diameter asteroid deflected 300,000 Km over 10 years
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20. Superconducting Lift Engines
Use as lift engine to counteract gravity.Liquid hydrogen cooling
Conventional propulsion for vehicle acceleration.Hydrogen fuelled
Hybrid reusable launch vehicle tonne launch vehicle
- Four 22 kW lift engines tonne thrust ascent rocket engine tonne thrust orbital rocket engine
- 20 tonnes payload to LEO Vehicle shape optimised for re-entry
- Vertical landing
Terrestrial transport
- A major incentive to change to a hydrogen based economy
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21. Status of current programmes
US Programme
Visit to major US aerospace company made in Sept 2006
Subsequent transfer of basic theoretical and experimental results (all now available in Public Domain)
Request for export licence made by US, based on an End User Undertaking for a military flight demonstrator programme
Export licence granted by UK January 2008
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22. Programme in China 1991 First UK patent published
1994 First Chinese patent published
2006 Initial contacts made by Chinese industry
2007 NWPU programme started at Xian
April Visit to Xian University
August Initial NWPU simulation results provided
Current activities include manufacture of large S Band thruster
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23. SPR Current Programmes
Flight Model programme Equipment specification issued Initial design work completed Development started
Demonstrator satellite proposal kg 100W microsatellite LEO satellite inspection mission Continuous manoeuvring in LEO LEO to GEO transfer after10 months Earth escape after 3 years Terminal vel 16.5km/sec after 7yrs
Design study for 2nd Generation Demonstrator vehicle
Uses four 3kW lift engines cooled by liquid hydrogen
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24. Feasibility Study for 2nd generation engine
Experimental 40W superconducting thruster using liquid nitrogen cooling
Measured Q =6.8x106
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25. The Next Step ? EmDrive is a British Invention
R&D has been funded by UK Government and British investors
Within a few years:
Military satellites without EmDrive will not be Fit for Pupose
Commercial satellites without EmDrive will not be sold
Science missions without EmDrive will not be considered
Will UK military, commercial and scientific space interests exploit the technical lead we presently hold ?
SPR Ltd