The European Solar Sail Technology
Status
The European Solar Sail Technology Status
Solar Sail means:to sail with the photon stream of the Sun –not in solar wind (1000/1!)
等爱The range of thrust provided by solid and liquid rockets is on the order of 5 to 5,000,000 N.
中煤第七十一工程处
Cold gas system, which uses an inert gas stored at a high pressure as propellant create thrust
from about 0.05 to 200 N-but they are the heaviest systems available with respect to their performance capabilities.
The thrust created by electrical propulsion systems is relatively small also, however, being on
the same level as cold gas systems.
At best case a solar sail will receive only force of 9 N/km2located in Earth orbit and the sail
ship is slowly but continuously accelerated to accomplish a wide-range of potential missions. These propulsion technology systems eventually could lead to missions to study the Sun and
its heliosphere-the magnetized bubble of plasma around the Sun -that are impossible using today’s technology
After successful deployment test on ground in 1998an ESA/DLR-Project was
planned:
Solar Sail 2003: 20x20 m only Deployment Demonstrator, 2004: 50x50 m Sailing Ship, 2006: 100x100 m Sailing Ship & PayLoad
Status now:
-Phase B for Deployment Demonstrator successful completed in 2004 –but up to now no funding for phase C/D.
-Study phase for a new mission “GEOSAIL”in cooperation with KT as prime contractor for ESA was started in 11/2006.
The European Solar Sail Technology Status
Solar Sail/Basics
Required minimum acceleration as defined for sailing: in the range 0,1 to 1 mm s -2Because permanent available, increase of velocity per year up to 31,5 km s -1!!!As result it would be possible to realize a transfer Earth to Mars within ca 400 days (correspond to transfer time for chemical propulsion)
Problem: Acceleration for a solar sail is inverted to its mass:
State of the art: 7,5 μm foils with σsail =5,5 g m -2 is available and space proofed (would have max. 1,53 mm s -2acceleration (sail ship, without payload!))To ensure a required minimum acceleration of 1 mm s -2for the system, only 2,8 g payload pro m 2are permissible
For typical 100 kg (payload + service unit) a 35000 m 2sail is required. That means square with approx. 190 m basis length!
But because theoretical reasons, even for sail foils with σsail = 0, for 1AU no more payload than 8,3 g m -2is possible!!!
()sail
payload
a c I r σσ−⋅+=min
1stkx
The European Solar Sail Technology Status
Solar Sail/Basics
Because orbit-mechanical reasons only two orbit maneuvers are possible:orbit expanding and orbit shrinking Orbit expanding
expanding orbit
Sun
Incident light
Solar Sail Reflected sunlight含泪劝告 Force component forward along orbit
Net force vector from light pressure
Force component away from sun
Sails orbit direction
The European Solar Sail Technology Status
Solar Sail/Basics
Orbit shrinking
shrinking orbit
Sun Incident light
Solar Sail
Reflected sunlight
Force component back along orbit Net force vector from light pressure Force component away from sun
Sails orbit direction
The European Solar Sail Technology Status
麦克白夫人Solar Sail/Configurations
Deployed by Booms solidly build and stiffly
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