EmDrive is a remarkable new space propulsion technology which uses microwave technology to convert electrical energy directly into thrust. No propellant is used in the conversion process. Thrust is produced by the amplification of the asymmetric radiation force from an electromagnetic wave propagated through a tapered resonant cavity.

The small UK based company that developed this technology, Satellite Propulsion Research Ltd, (SPR Ltd) has completed the research phase and has now closed down. All patents have been allowed to expire, which will enable EmDrive thrusters to be manufactured and sold worldwide without commercial restrictions.

The theory, design and applications of the technology, together with the development of further generations, are detailed in the book described in the publisher’s link given in the latest news.

The author’s email address remains sprltd@emdrive.com

Latest news

December 2023

The book EmDrive: Advances in Spacecraft Thrusters and Propulsion Systems has now been published.

The link to the publisher’s webpage is here: EmDrive: Advances in Spacecraft Thrusters and Propulsion Systems

November 2023

With the publication of the EmDrive book due next month, a new page has been produced for this site which lists many of the references given in the book, and provides links to those references.

The page can be accessed here: Book references.

October 2023

A book titled EmDrive: Advances in Spacecraft Thrusters and Propulsion Systems will be published by CRC press on December 12 2023.

The link to the publisher’s webpage is here: EmDrive: Advances in Spacecraft Thrusters and Propulsion Systems

December 2021

The SPR Ltd papers for this year’s IAC-21 conference in Dubai can be downloaded here:

The impact of EmDrive Propulsion on the Launch Costs for Solar Power Satellites

A Superconducting EmDrive Thruster. Design, Performance and Application

Also a note on the geometry of the latest TU Dresden cavity, explaining why it does not work as an EmDrive thruster is given here:

A Note on the TU Dresden IAC-21 paper

November 2021

Two ten minute video lectures were presented at the IAC-21 conference in Dubai. The lectures can be seen here:

The impact of EmDrive Propulsion on the Launch Costs for Solar Power Satellites

A Superconducting EmDrive Thruster. Design, Performance and Application

April 2021

Notes on the recent Dresden TU paper, explaining why their thrust measurements for the NASA replica thruster are zero, are given here: Dresden TU 2021 notes

April 2021

A talk on EmDrive theory, Engineering and Applications will be given to APEC on April 3rd at 12:00 US Pacific Time.

Registration for the conference can be made free at www.altpropulsion.com

A recording of the talk can be viewed here: APEC 4/3,Part#1-Roger Shawyer-EmDrive-YouTube

A recording of the Q&A session can be found here: APEC 4/3,Part#2-Roger Shawyer-Q&A session-YouTube

January 2021

An explanation of some fundamental principles of EmDrive operation is given here, to help increase public understanding of EmDrive:

EmDrive Fundamentals

October 2020

The paper entitled An EmDrive Thruster for Cubesats, presented at the IAC-20 conference is given here, together with the associated Bio: IAC-20 Paper; IAC-20 Bio

The IAC-20 presentation may be viewed here: IAC-20 Presentation

May 2020

A recorded version of the postponed UCL lecture, The Technologies of Hope, which was to be given on April 2nd, can be seen here:

UCL Lecture: The Technologies of Hope

February 2020

A public lecture on EmDrive and its application in solutions to climate change will be given at University College London on April 2nd. The details for the lecture are given here:


January 2020

The IAC 2019 conference presentation entitled “EmDrive Thrust/Load Characteristics. Theory, Experimental Results and a Moon Mission” is given here: IAC 2019 Presentation

October 2019

The full IAC 2019 paper entitled “EmDrive Thrust/Load Characteristics. Theory, Experimental Results and a Moon Mission” is given here: IAC 2019 Paper

October 2019

The abstract for the IAC 2019 conference in Washington this month is given here: IAC 2019 Abstract

September 2019

A copy of the original Flight Thruster Technical Report is given here. The report which was first produced in September 2010, was updated in December 2017 to include the original manufacturing drawings.

Also given are the Cullen and Bailey papers, which provided the original source material for the development of the EmDrive theory of operation.

These three files are referenced in the paper entitled, EmDrive Thrust/Load Characteristics. Theory, experimental Results and a Moon Mission. This paper will be given at the IAC 2019 conference in Washington next month.

Flight Thruster Report Issue 2

Cullen Paper 0001

Bailey RRE Paper

April 2019

SPR Ltd now has client agreement to release typical Thrust data from the Flight Thruster test programme. The data is given here. Notes on FM2 Test 101

February 2019

An edited copy of this year’s presentation at Shrivenham Defence Academy is given here. Note that this is the first time nominal experimental data showing the Thrust/Load response of an EmDrive Thruster has been released. Shrivenham Presentation 2019

December 2018

A short Technical Note on Thrust performance versus Load conditions of EmDrive Thrusters is given here. The note explains why EmDrive complies with both the Law of Conservation of Momentum, as well as the Law of Conservation of Energy. Technical Note on Emdrive Thrust v Load

July 2018

The following presentation was given at an EmDrive seminar held at Dresden Technical University on 11th July 2018. Dresden Seminar July 2018

May 2018

For those who are new to the EmDrive saga, the history and background is given in an interview with the inventor here: https://www.youtube.com/watch?v=KUX8EWxmS3k

The interview was carried out by Mary-Ann Russon of the International Business Times, and was originally released on 14 October 2016.

September 2017

Patent GB 2493361 entitled High Q microwave radiation thruster has now been granted by the UK Intellectual Property Office.

A short note on general principles of EmDrive design and manufacture can be downloaded here:

General Principles of EmDrive design

August 2017 - EmDrive Efficiency

A short presentation on EmDrive thruster efficiency can be downloaded here.

EmDrive Efficiency

August 2017

A short presentation on Third Generation EmDrive can be downloaded here.

3G EmDrive

June 2017

An edited set of slides from a presentation made to the UK Defence Academy in February this year can be downloaded here. They give the background story to the emergence of EmDrive, and illustrate how important Global Defence applications are to the continuing development of the technology.

Shrivenham Presentation

September 2016

A slide presentation with narration, explaining the basic science behind EmDrive can be downloaded here.


August 2016

Development work is continuing on superconducting EmDrive thruster technology in co-operation with a UK aerospace company. No details of this work can be divulged at present.

However, as it is now 10 years since the completion of the original research work, the documents reporting on this work can be released, and can be accessed here.

Feasibility study technical report. Issue 2

Review of experimental thruster report

Demonstrator technical report. Issue 2

Review of DM tech report

The documents are two final technical reports and two independent reviews, and date from July 2002 to August 2006. The work was carried out for the UK government under their SMART and R&D award programmes. Documentation was shared with US government organisations.

The research was carried out concurrently with the BAE Systems Greenglow project, which was the subject of a BBC Horizon programme broadcast in March this year.

July 2015

A peer reviewed version of the IAC14 conference paper is given here: IAC14 Paper

A 5 minute audioslide presentation of the IAC14 paper, updated to include the latest test data from the University of Dresden Germany, is given here: IAC14 Audioslide (.avi 11MB)

June 2015

The full test video of one of the dynamic test runs of the Demonstrator engine has been released and is available here: Dynamic Test (.mpg 43MB) or Dynamic Test (.avi 112MB)

Notes giving an explanation of the test rig and this particular test run are given here: Notes on Dynamic Test

May 2015

A recent interview with Roger Shawyer, filmed by Nick Breeze, can be found here: 2015 Interview

January 2015

A number of research groups have asked questions on the methods of measuring EmDrive forces. A note explaining the principles can be found here: EmDrive Force Measurement

October 2014

At the IAC 2014 conference in Toronto, Roger Shawyer stated that 8 sets of test data have now verified EmDrive theory. These data sets resulted from thrust measurements on 7 different thrusters, by 4 independent organisations, in 3 different countries.
The Toronto presentation can be found here: IAC14 Presentation

August 2014

A recent interview with Roger Shawyer, recorded by Nick Breeze at the Royal Institution in London can be found here: Interview It is accompanied by a PowerPoint presentation entitled “EmDrive-Enabling a Better Future”.

July 2014

A paper entitled "Second Generation EmDrive Propulsion Applied to SSTO Launcher and Interstellar Probe" will be presented at the 65th International Astronautical Congress 2014 at Toronto in September.

October 2013

A paper entitled "The Dynamic Operation of a High Q EmDrive Microwave Thruster" and the associated poster for the recent IAC13 conference in Beijing is given here: IAC13 PaperIAC13 Poster

November 2012

China publishes high power test results

The prestigious Chinese Academy of Sciences has published a paper by Professor Yang Juan confirming their high power test results. At an input power of 2.5kW, their 2.45GHz EmDrive thruster provides 720mN of thrust. The results have clearly been subject to extensive peer review following the NWPU 2010 paper. The measurements were made on a national standard, thrust measurement device, used for Ion Engine development. Details of the measurement system and calibration data are given in the paper. A professional English translation is given here: Yang Juan 2012 paper

September 2012

A solution to the acceleration limitation of superconducting EmDrive engines has been found. The application of this breakthrough has been described at a recent presentation, where a hybrid spaceplane provides a dramatic reduction in launch cost to geostationary orbit. A reduction factor of 130 compared to Atlas V launch costs is predicted. This will lead to Solar Power Satellites becoming a low cost, baseload, energy source. The presentation can be downloaded here: 2G update

July 2012

An English translation of the 2010 Chinese paper, together with unpublished test results have been obtained. The last line of the paper confirms that experimental thrust measurements have been made at 1kW input power. The unpublished test results show a large number of thrust measurements at input powers up to 2.5kW. The mean specific thrust obtained is close to that measured in the SPR flight thruster tests.

Note that the Chinese thruster, if deployed on the ISS, would easily provide the necessary delta V to compensate for orbital decay, thus eliminating the need for the reboost/refueling missions.

The original 2010 paper, the translation and the unpublished test results are given here:

NWPU 2010 paper

NWPU 2010 paper (English translation)

NWPU 2010 unpublished test results

June 2011

Two papers have been identified, published by Professor Yang Juan of The North Western Polytechnical University, Xi'an, China. These papers provide an independent proof of the theory of EmDrive. Abstracts of these papers are given in Chinese Paper Abstracts. The originals are written in Chinese.

August 2010

A Technology Transfer contract with a major US aerospace company was successfully completed. This 10 month contract was carried out under a UK Export Licence and a TAA issued by the US State Department. Details are subject to ITAR regulations.

June 2010

A paper was presented at the 2nd Conference on Disruptive Technology in Space Activities. See: Toulouse 2010 Paper

Earlier papers presented in a series of international conferences were:

Brighton 2005 paper

IAC 2008 paper

CEAS 2009 paper

May 2010

The Flight Thruster test programme was successfully completed. See: Flight Programme