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

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

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

Why Launch satellites? Fear Military applications e.g. NATO 1VB Greed Commercial applications e.g. HOTBIRD 2 Curiosity Scientific missions e.g. SMART 1

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

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

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

Production of net thrust Propagation velocity has a highly non linear relationship with waveguide diameter 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 F 1 F 2 F 3 Area A 1 Area A 3 Area A 2

Conservation of Momentum F 2 F 1 Reaction Force F=Ma Thrust T=Q(F 1 -F 2 ) 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

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= 5x10 4 (1st generation EmDrive) Static specific thrust =315mN/kW Specific thrust at 3 km/s = 200mN/kw For Q = 5x10 9 (superconducting) Static specific thrust = 31.5 kN/kW Specific thrust at 0.1 m/s = 8.8 kN/kW

Experimental Programme 2001 DTI SMART Award Experimental Thruster 2002 Proof of Concept 2003 DTI R&D Grant awarded Demonstrator Engine 2007 Demonstrator Engine tests complete 2008 Superconducting Thruster tests start

Experimental Thruster Demonstrator Engine ( 2002) (2006) Static specific thrust = 19mN/kW Static specific thrust = 214mN/kW

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

Dynamic Test Rig (2007) Acceleration of 100kg beam supported on air bearing to 2 cm/s Dynamic specific thrust = 287mN/kW

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

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

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

Science Mission Applications Comparison with SNECMA PPS1350 system performance for ESA SMART 1 Luna Probe mission

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)

Second Generation Engines Superconducting technology can give thrust increase x 10 5 Superconducting cavities in production for high energy physics experiments e.g. Q=2x10 9 for LHC at CERN and 5x10 9 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

Superconducting Lift Engines Use as lift engine to counteract gravity.Liquid hydrogen cooling Conventional propulsion for vehicle acceleration.Hydrogen fuelled Hybrid reusable launch vehicle -260 tonne launch vehicle - Four 22 kW lift engines - 1 tonne thrust ascent rocket engine - 50 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

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

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 2008 Visit to Xian University August 2008 Initial NWPU simulation results provided Current activities include manufacture of large S Band thruster

SPR Current Programmes Flight Model programme Equipment specification issued Initial design work completed Development started Demonstrator satellite proposal 100kg 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

SPR Current Programmes

Flight Model programme Equipment specification issued Initial design work completed Development started

Demonstrator satellite proposal 100kg 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

Feasibility Study for 2nd generation engine Experimental 40W superconducting thruster using liquid nitrogen cooling Measured Q =6.8x10 6

Feasibility Study for 2nd generation engine

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 ?