Project Icarus: Starship Pegasus Makes Progress

Recently several meetings have taken place of some core members of the Project Icarus Study Group. These discussions have included Kelvin F Long (co-founder of the project), Richard Osborne, Michel Lamontagne, Robert Freeland and Rob Swinney (current Project Leader). The team is trying to make progress towards closing out the study, first initiated in September 2009, and so has been going for double the length of the Project Daedalus study. The emphasis on these specific meetings has been on progressing one of the designs towards a greater fidelity of completion.

The design started out as Starship Resolution which had a single engine stage for both the acceleration and deceleration phase and was based on the design of the Daedalus 2nd stage engine. In a need to bring down the 15 year boost time, then then evolved to Starship Endeavour which was a paralised thrust system with a quintec engine arrangement, that is 5-engine bells similar to the Saturn V rocket that took men to the Moon. One of the concerns about this design however has been the high radiation and neutron environment generated from these different engines and how they couple up to each other. This then led to a new 4-engine arrangement which has been named Starship Pegasus. The image below shows the transition from a 5-engine staged Endeavour to a 4-engine staged system and was the baseline for the Pegasus design, although is now undergoing significant revision with the inclusion of radiator fins specifically.

***4-engine Staged Endeavour (progenitor to Pegasus) [M. Lamontagne]***

Currently, Kelvin F Long has been progressing the design model, built in a Fortran 95 code, and his efforts are now also focussed on the implosion, ignition and burn model for the inertial confinement fusion capsules utilised by the engine. But in addition, Richard Osborne has been working on many of the other systems and the power supply and radiators have been given special attention and he has been working with the others to produce something that is sensible and then folding out a new configuration arrangement for the vehicle layout. Robert and Michel had put a lot of effort into the design of the radiator fins for the Icarus Firefly design [1, 2] and that experience has been well utilised for the Pegasus design. Although preliminary calculations are suggesting that large radiators may not be needed, they are being included as a design margin and to allow for uncertainties. This is in addition to an insulator, to help mop up the x-rays and high energy neutrons. Further, an innovative capsule design is being utilised to help mitigate the offending energy release. Terry Regan has also been attending some of the meetings and lending his wisdom to the design considerations.

Over the last few months several meetings have taken place between these people to include:

Friday 6th September 2019. Discussion on radiator fins and engine arrangement.
Friday 11th and Saturday 12th October 2019, special workshop on Project Icarus Concept Design Fusion Ignition Physics and Engineering Propulsion. The main focus was on the implosion and ignition system but with some discussion on radiators, power systems and configuration layout.
Monday 28th October 2019, discussion on configuration layout.
Friday 22nd (radiators) and Sunday 24th (power systems) November 2019.

Although Project Icarus has taken a lot of time to complete, the team hopes that the final study report will be published in 2020, and that the additional effort that has gone into the report by certain team members to improve its quality will justify the end product. For those still waiting for the output of this work, watch this space.

References:

R. Freeland, Plasma Dynamics in Firefly’s Z-Pinch Fusion Engine, 71, pp.288-293, Journal of the British Interplanetary Society, 2018.
M. Lamontagne, Heat Transfer in Fusion Starship Radiation Shielding Systems, 71, pp.450-457, Journal of the British Interplanetary Society, 2018.