Chevaline Polaris Post Boost Propulsion System – The Twin Chamber Propulsion Unit (TCPU) by Paul Jackman, John Harlow & Mark Perman

Date: 18 September 2021
Time: 12:00 am - 12:00 am
Location: Zoom
BIS Events | BIS West Midlands

The West Midlands Branch presents:

Chevaline Polaris Post Boost Propulsion System – The Twin Chamber Propulsion Unit (TCPU) by Paul Jackman, John Harlow & Mark Perman

In order to maintain a credible threat in times of increasingly sophisticated Soviet defence systems the Polaris Sea Launched Ballistic Missile System needed upgrading. Studies showed that such an effective upgrade could be achieved by changing the existing Polaris missile payload to one able to place items along the target Null Range Vector (NRV). These objects included re-entry bodies, sub-missiles and other free flying disguises. Thus, Chevaline was born.

For a really effective system capable of fully exploiting the NRV approach, either the Chevaline bus (called the Penetration Aid Carrier – PAC) and/or the objects it carried needed some form of propulsion.

This talk introduces some aspects of the decision to opt for a liquid propellant solution for the PAC rather than a solid propellant one.

The main theme of the talk is the design, development and operational use of the selected option the liquid propellant solution – the TCPU.


Paul Jackman graduated from Brunel University with an honours degree in Mechanical Engineering in 1967 and joined RPE Westcott to undertake empirical research into the mixing and combustion of hypergolic liquid bi-propellants. He went on to develop the injectors and thrust chambers for the successful packaged liquid test vehicle (PLTV) series of flight demonstrations. This led to the development of the engines for the Chevaline Twin Chamber Propulsion Unit (TCPU).

When the Chevaline programme cancelled the hot gas AOCS in favour of the American Hydrazine Actuation System (HAS) Paul became a member of the special HAS procurement team.

As the programme progressed Paul became Chevaline Motors Programme Manager overseeing the introduction into service of all the Westcott designed solid Chevaline motors as well as TCPU and HAS.

Paul then held various senior management position in the BAE Systems rocket motors facilities managing several major programmes including the development and sale to US satellite prime contractors of the Westcott liquid propellant Apogee and AOCS engines.

For many years Paul served on the I.Mech.E. Propulsion Technical Activities Committee and the AIAA Solid Rocket Technical Committee.

Paul retired as Chief Engineer BAE Systems, Royal Ordnance, Rocket Motors Division in 2002.

John Harlow has had a very interesting career being fortunate enough to have spent a lot of time involved with the technical aspects of rocketry. Having cut his teeth on Polaris, John went on to work on both launchers and other re-entry systems. He has worked for and/or with the MoD, Foreign Office, United Nations to name but a few and this has taken him to most satellite Prime Contractors and launch facilities around the planet.

He is a Past President of the BIS, and a member of the IAA History Committee.

Meeting Timetable

  • 13:55 – The meeting is available to join
  • 14:00 – Welcome
  • 14:05 – Chevaline Polaris Post Boost Propulsion System – The Twin Chamber Propulsion Unit (TCPU) by Paul Jackman & John Harlow
  • 14:35 – Questions and Answers (we enable everyone’s microphone to allow an interactive Q&A session)

Plan/Joining Instructions:

  1. Register for the Talk using the link below
  3. Before the event, we will send you an email with the joining link for the meeting.
  4. On the day, click meeting link (and follow the on-screen instructions to install Zoom if prompted)

Please Note

The Conference Call and Q & A sessions will be recorded (which may capture your name, picture, voice or video) and made available via the West Midlands Facebook group and possibly via the BIS HQ website. You consent to this by registering for the Conference Call/Q & A sessions.