Project Icarus Study Group1

Project Icarus: Solar Sail Technology

for theIcarus Interstellar Mission

Project Icarus Study Group

Internet: http://icarusinterstellar.org/ E-mail: info@icarusinterstellar.org

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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

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Project Icarus

• Tau Zero Foundation initiative in collaboration with The British Interplanetary Society.

• Officially began30 September 2009.

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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

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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

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Case #1

Deceleration at Target Star

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Deceleration at Alpha Centauri A

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Deceleration – Realistic Sail

• Hollow-Body Beryllium Sail• Capture at 0.066 AU• σsail = 4 × 10−5 kg/m2

• ρ = 0.9

Sail Deceleration (Hollow-Body Sail)

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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

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Deceleration – ‘Ideal’ Sail

• Capture at 0.066 AU• σsail ≥ 0• ρ = 1

Sail Deceleration (Ideal Sail)

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Sail Deceleration (Ideal Sail)

Assume:• Icarus encounter mass = 50,000 kg• Interstellar speed = 0.1c

Sail diameter required ≈ 944 km

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Case #2

Deployment of

Gravitational Lens Relay Station

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Gravitational Lens Relay Station

Not to scale!

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Gravitational Lens Relay Station

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Grav Lens Relay Deployment

Assume:• 10 GW laser (λ = 1μm)• Lens diameter = 1 km• Sail ρ = 0.85• σ = 1 g/m2

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Grav Lens Relay Deployment Time

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Grav Lens Relay Deployment

Payload mass of 300 kg

Delivered to 700 AU in 10 years

Sail diameter ≈ 620 m

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Case #3

Boost from Solar System

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Boost from Solar System

Assume:• Icarus launch mass = 50,000 tonnes• Sail ρ = 0.85• Laser pushed

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Boost from Solar System

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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

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Case #4

Deployment of Sub-Probes in Target System

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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

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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

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Project Icarus

Internet: http://icarusinterstellar.org/