Project Icarus Study Group 1 Project Icarus: Solar Sail Technology for the Icarus Interstellar Mission Project Icarus Study Group Internet:

Project Icarus Study Group 2 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 3 Project Icarus Tau Zero Foundation initiative in collaboration with The British Interplanetary Society. Officially began 30 September 2009.

Project Icarus Study Group 4 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 5 Icarus Parameters Interstellar cruise speed 0.1—0.2c Launch mass (Daedalus) ≈ 50,000 tonnes Encounter mass (Daedalus) ≈ 50,000 kg

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 6

Case #1 Deceleration at Target Star Project Icarus Study Group 7

8 Deceleration at Alpha Centauri A

Project Icarus Study Group 9 Deceleration – Realistic Sail Hollow-Body Beryllium Sail Capture at AU σ sail = 4 × 10 −5 kg/m 2 ρ = 0.9

Sail Deceleration (Hollow-Body Sail) Project Icarus Study Group 10

Sail Deceleration (Hollow-Body Sail) Limiting case of no payload: v i ≈ 0.004c (1200 km/s) Therefore 96-98% of deceleration must occur before the sail is used Project Icarus Study Group 11

Project Icarus Study Group 12 Deceleration – ‘Ideal’ Sail Capture at AU σ sail ≥ 0 ρ = 1

Sail Deceleration (Ideal Sail) Project Icarus Study Group 13

Sail Deceleration (Ideal Sail) Assume: Icarus encounter mass = 50,000 kg Interstellar speed = 0.1c Sail diameter required ≈ 944 km Project Icarus Study Group 14

Case #2 Deployment of Gravitational Lens Relay Station Project Icarus Study Group 15

Gravitational Lens Relay Station Not to scale! Project Icarus Study Group 16

Gravitational Lens Relay Station Project Icarus Study Group 17

Grav Lens Relay Deployment Assume: 10 GW laser (λ = 1μm) Lens diameter = 1 km Sail ρ = 0.85 σ = 1 g/m 2 Project Icarus Study Group 18

Grav Lens Relay Deployment Time Project Icarus Study Group 19

Grav Lens Relay Deployment Payload mass of 300 kg Delivered to 700 AU in 10 years Sail diameter ≈ 620 m Project Icarus Study Group 20

Case #3 Boost from Solar System Project Icarus Study Group 21

Boost from Solar System Assume: Icarus launch mass = 50,000 tonnes Sail ρ = 0.85 Laser pushed Project Icarus Study Group 22

Boost from Solar System Project Icarus Study Group 23

Boost from Solar System Assume: 100 GW laser (λ = 1μm) Lens diameter = 100 km σ = 1 g/m 2 Then: Terminal velocity ≈ 0.002c Sail diameter ≈ 250 km Project Icarus Study Group 24

Case #4 Deployment of Sub-Probes in Target System Project Icarus Study Group 25

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 26

Project Icarus Study Group 27 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 28 Project Icarus Internet: