Project Icarus: Solar Sail Technology for the Icarus Interstellar Mission

Project Icarus: Solar Sail Technologyfor theIcarus Interstellar Mission Project Icarus Study Group Internet: http://icarusinterstellar.org/ E-mail: info@icarusinterstellar.org Project Icarus Study Group

Project Daedalus Design study between 1973—1978 • Considered the challenges of interstellar travel • Used current/near-future technology • Reach destination within a human lifetime • Allow for a variety of target stars Project Icarus Study Group

Project Icarus • Tau Zero Foundation initiative in collaboration with The British Interplanetary Society. • Officially began30 September 2009. Project Icarus Study Group

Icarus Project Requirements • Unmanned probe • Current or near-future technology • Reach destination as fast as possible • Variety of target stars • Propulsion mainly fusion based • Deceleration for prolonged encounter time Project Icarus Study Group

Icarus Parameters • Interstellar cruise speed 0.1—0.2c • Launch mass (Daedalus) ≈ 50,000 tonnes • Encounter mass (Daedalus) ≈ 50,000 kg Project Icarus Study Group

Potential Sail Uses • Boost from solar system • Deceleration at target star • Deployment of gravitational lens relay • Deployment of sub-probes in target system Project Icarus Study Group

Case #1 Deceleration at Target Star Project Icarus Study Group

Deceleration at Alpha Centauri A Project Icarus Study Group

Deceleration – Realistic Sail • Hollow-Body Beryllium Sail • Capture at 0.066 AU • σsail = 4 × 10−5 kg/m2 • ρ = 0.9 Project Icarus Study Group

Sail Deceleration (Hollow-Body Sail) Project Icarus Study Group

Sail Deceleration (Hollow-Body Sail) • Limiting case of no payload:vi ≈ 0.004c (1200 km/s) • Therefore 96-98% of deceleration must occur before the sail is used Project Icarus Study Group

Deceleration – ‘Ideal’ Sail • Capture at 0.066 AU • σsail ≥ 0 • ρ = 1 Project Icarus Study Group

Sail Deceleration (Ideal Sail) Project Icarus Study Group

Sail Deceleration (Ideal Sail) Assume: • Icarus encounter mass = 50,000 kg • Interstellar speed = 0.1c Sail diameter required ≈ 944 km Project Icarus Study Group

Case #2 Deployment of Gravitational Lens Relay Station Project Icarus Study Group

Gravitational Lens Relay Station Not to scale! Project Icarus Study Group

Gravitational Lens Relay Station Project Icarus Study Group

Grav Lens Relay Deployment Assume: • 10 GW laser (λ = 1μm) • Lens diameter = 1 km • Sail ρ = 0.85 • σ = 1 g/m2 Project Icarus Study Group

Grav Lens Relay Deployment Time Project Icarus Study Group

Grav Lens Relay Deployment Payload mass of 300 kg Delivered to 700 AU in 10 years Sail diameter ≈ 620 m Project Icarus Study Group

Case #3 Boost from Solar System Project Icarus Study Group

Boost from Solar System Assume: • Icarus launch mass = 50,000 tonnes • Sail ρ = 0.85 • Laser pushed Project Icarus Study Group

Boost from Solar System Project Icarus Study Group

Boost from Solar System Assume: • 100 GW laser (λ = 1μm) • Lens diameter = 100 km • σ = 1 g/m2 Then: • Terminal velocity ≈ 0.002c • Sail diameter ≈ 250 km Project Icarus Study Group

Case #4 Deployment of Sub-Probes in Target System Project Icarus Study Group

Deployment of Sub-Probes • Assume Icarus is captured into a close orbit of the star • Analogous to deploying interplanetary probes in our solar system • Could reach outer planets in a decade or two • Non-Keplerian orbits possible • Change of inclination e.g. cranking Project Icarus Study Group

Summary • Sails not realistic for boost or deceleration of main craft • Potential for deployment of gravitational lens relay (using laser push • Potential for deployment of sub-probes Project Icarus Study Group

Project Icarus Internet: http://icarusinterstellar.org/ Project Icarus Study Group

Project Icarus: Solar Sail Technology for the Icarus Interstellar Mission