19-04-2012, 03:38 PM
Wireless Power Transmission Options for Space Solar Power
solar power wpt_options_for_ssp_potter.pdf (Size: 925.2 KB / Downloads: 37)
Near-Term Market: Military Bases
• Much of the cost in lives and dollars of operating a military base
in a war environment is due to the delivery of fuel
• Cost of delivery of gasoline under such circumstances is about
$100/gallon, which contains 130 megajoules of energy = 36 kWh
• At this rate, 40 remote military bases (each using 5 MW) will
require 40 bases x 5 MW/base x 24 hours/day x 30 days/month =
144,000 MWh/month
• This is equivalent to 4,000,000 gallons of fuel per month or $400
million per month for fuel.
– Conversion from thermal to electrical energy not accounted for.
Actual fuel usage will be higher.
• These bases, using a total of 200 MW could instead be supplied
by just 20% of the power beamed from a single 1 GW power
satellite
• may be 6
Graceful growth toward this market achievable by
considering a constellation of smaller (5 to 10 MW) satellites.
Orbit Trade Study: Inclination
• Low Inclination
– Pros:
• Natural inclination for GEO orbits
• Low delta-V
– Cons:
• LEO satellites would be in darkness much of the time
• LEO satellites may not be visible at middle and high latitudes
• High Inclination
– Pros:
• Ground track may cover inhabited areas, so that greater use can be attained
by LEO and MEO satellites
• Sun-synchronous orbits may be achievable for LEO orbits, keeping them in
sunlight much of the time if orbit is over terminator
– Cons:
• Higher delta-v for a given altitude
• If sun-synchronous, time of overflight would be required to be near sunrise
and sunset each orbit
– This could constrain choice of altitudes if repeating ground track is desired
Initial Photovoltaic / Microwave SPS GEO Sun Tower Conceptual Design
•“Sun-Tower” Design based
on NASA Fresh Look Study
• Transmitter Diameter:
500 meters
•Vertical “Backbone” Length:
15.3 km (gravity gradient)
•Identical Satellite Elements:
•Autonomous Segment Ops:
1) Solar Electric Propulsion
from Low Earth Orbit
355 segments (solar arrays)
2) System Assembly in
Geostationary orbit
Summary
• Farther-term micro-wave WPT options are efficient, and can beam
power through clouds / light rain, but require large sizes for long
distance WPT and a specialized receiver (“rectenna”).
• Nearer-term Laser-Photovoltaic WPT options are less efficient, but
allow synergistic use of the same photovoltaic receiver for both
terrestrial solar power and SSP.
• Boeing is currently investigating near-term military, civil government,
and commercial markets for SSP.
• Technology flight demonstrations can enable advanced space science
and exploration in the near term.
– “Power Plug” or “LAMP” spacecraft and Lunar Polar Solar Power outpost
advance technology for far-term commercial SSP systems, while providing
significant value for near-term applications.
solar power wpt_options_for_ssp_potter.pdf (Size: 925.2 KB / Downloads: 37)
Near-Term Market: Military Bases
• Much of the cost in lives and dollars of operating a military base
in a war environment is due to the delivery of fuel
• Cost of delivery of gasoline under such circumstances is about
$100/gallon, which contains 130 megajoules of energy = 36 kWh
• At this rate, 40 remote military bases (each using 5 MW) will
require 40 bases x 5 MW/base x 24 hours/day x 30 days/month =
144,000 MWh/month
• This is equivalent to 4,000,000 gallons of fuel per month or $400
million per month for fuel.
– Conversion from thermal to electrical energy not accounted for.
Actual fuel usage will be higher.
• These bases, using a total of 200 MW could instead be supplied
by just 20% of the power beamed from a single 1 GW power
satellite
• may be 6
Graceful growth toward this market achievable by
considering a constellation of smaller (5 to 10 MW) satellites.
Orbit Trade Study: Inclination
• Low Inclination
– Pros:
• Natural inclination for GEO orbits
• Low delta-V
– Cons:
• LEO satellites would be in darkness much of the time
• LEO satellites may not be visible at middle and high latitudes
• High Inclination
– Pros:
• Ground track may cover inhabited areas, so that greater use can be attained
by LEO and MEO satellites
• Sun-synchronous orbits may be achievable for LEO orbits, keeping them in
sunlight much of the time if orbit is over terminator
– Cons:
• Higher delta-v for a given altitude
• If sun-synchronous, time of overflight would be required to be near sunrise
and sunset each orbit
– This could constrain choice of altitudes if repeating ground track is desired
Initial Photovoltaic / Microwave SPS GEO Sun Tower Conceptual Design
•“Sun-Tower” Design based
on NASA Fresh Look Study
• Transmitter Diameter:
500 meters
•Vertical “Backbone” Length:
15.3 km (gravity gradient)
•Identical Satellite Elements:
•Autonomous Segment Ops:
1) Solar Electric Propulsion
from Low Earth Orbit
355 segments (solar arrays)
2) System Assembly in
Geostationary orbit
Summary
• Farther-term micro-wave WPT options are efficient, and can beam
power through clouds / light rain, but require large sizes for long
distance WPT and a specialized receiver (“rectenna”).
• Nearer-term Laser-Photovoltaic WPT options are less efficient, but
allow synergistic use of the same photovoltaic receiver for both
terrestrial solar power and SSP.
• Boeing is currently investigating near-term military, civil government,
and commercial markets for SSP.
• Technology flight demonstrations can enable advanced space science
and exploration in the near term.
– “Power Plug” or “LAMP” spacecraft and Lunar Polar Solar Power outpost
advance technology for far-term commercial SSP systems, while providing
significant value for near-term applications.