Title: Space Solar Power (SSP)

Source & Date

Al Globus. Senior Research Associate. San Jose State University Foundation.

April 2007.

Background

We are currently facing two serious, energy related problems. The first is a large recent increase in the price of oil, which is putting severe strains on the economies of many nations. The second is an increase in atmospheric CO2 leading to global warming caused, to at least some degree, by burning fossil fuels to produce energy. Furthermore, the total quantity of fossil fuels is limited and there is some indication that oil production will begin to decline soon. To solve these problems, we need a large scale, clean, inexpensive source of energy.

The largest source of energy in the solar system is the sun, and the vast majority of this energy is radiated into space. In 1968, Peter Glaser proposed developing Space Solar Power (SSP). The idea is to gather solar energy in space, where it is plentiful and available 24/7, and beam it to Earth wirelessly. Solar energy is regularly used for satellite power and wireless energy transmission has been demonstrated on the ground in microwave frequencies. An SSP system based on solar cells in space and microwave transmission to Earth may be as much as 10% solar-energy-at-the-satellite to base-load-power-on-Earth efficient and there could be better options. SSP involves no atmospheric emissions, requires no fuel, and will be available for billions of years. Develop profitable SSP and our energy problems will be completely solved.

The people of Earth currently consume approximately 18 terrawatts (TW) of energy. To replace all of the Earth's current energy use with Space Solar Power, assuming an optimistic 1kg/kw, will require placing 18 million tons of SSP satellite in orbit, or more. Not only is the dollar cost of launch from Earth extreme, but there is potential damage to the atmosphere from such a high launch rate. Most of these launches can be eliminated by building SSP satellites out of lunar materials. Most of the mass of these satellites is expected to be silicon and metals, both in large supply in ordinary lunar regolith. As the Moon is airless and has a much lower gravitational force at the surface, it is possible, at least in principle, to launch materials off of the Moon using an electromagnetic mass driver requiring only electricity, no fuel or reaction mass.

A note on oil and SSP. The majority of oil use is for automobile transportation Thus, with the current automobile fleet SSP cannot replace oil. However, in the U.S., oil account for only 2-3% of electrical generation and major manufacturers have announced plans, within two years, to sell plug-in hybrid automobiles that can travel up to 60 km on electrical power alone. In the U.S., this accounts for about 75% of all automobile travel. Electricity can replace most oil for auto travel, but this will require large quantities of electric power. Thus, it is reasonable to propose SSP as an oil replacement in the long term.

Issue

SSP requires Earth-to-Orbit transportation, kilometer-scale orbital construction, lunar mines, materials processing and launch, sufficiently large antennas and much else. Thus, SSP involves major technical and market risks which have inhibited development. This project is to design a program to retire both the technical and market risks to the point where SSP is commercially viable. For general power, this implies 5-10 cents per kw-h delivered to the grid. However, for remote locations electric power costs are closer to $1 per kw-h for generators and diesel fuel so higher initial costs are acceptable.

This project may be broken into two parts: one involving the design and construction of the first few SSP satellites which will certainly be launched from Earth, and a second involving the design and construction of lunar mines and materials processing to support SSP satellites built largely from lunar materials.

Assignment

The TP has the following assignment:

PART I

1) Define the requirements and representative point designs for a series of increasingly capable SSP demonstrator satellites to retire technical risk.

2) Define a system of monetary prizes to motivate the private sector to develop the demonstrators.

3) Define a scientific program to identify, quantify, and mitigate environmental risks; e.g., beam interaction with the atmosphere, effect on biota of expected microwave flux near and beneath the ground antenna, and the effects of many launches on the atmosphere.

4) Define a research program to develop component technologies

Part II

1) Define systems to mine lunar regolith and package it for launch.

2) Define a system to launch raw regolith into a suitable orbit.

3) Define systems to process lunar regolith into SSP satellite components

Disciplines

Expected level of involvement by department area

Business Life Policy Physical Satellite Systems Space

Management Science & Law Science Applications Engineering & Society

Major X X X X X X X

Minor       

Brief explanation of expected involvement by department area

Space Business & Management: Design the prizes such that private business will find it advantages to participate in demonstators and final system

Space Life Sciences: Determine the effects of microwave (or other beamed energy frequency) on biota

Space Policy & Law: Determine the legal implications of siting receiving antennas tens of kilometers across. In particular, will eminent domain be needed? Define ownership and mining rights to the lunar surface.

Space Physical Sciences: Determine the best frequencies for energy beams.

Satellite Applications: SSP is a satellite application

Space Systems Engineering: Design the SSP satellites and ground facilities, including in-orbit assembly. Define mining and packaging equipment. Define the mass driver and determine the location and velocities to achieve the desired orbits. Define processing steps to convert regolith into SSP components.

Space & Society: Determine the social and political implications should SSP become the dominant energy source on Earth, particularly with regard to warfare.

Window of Opportunity

This proposed TP is viable for the foreseeable future.

Interest

This proposed TP is likely to enjoy broad support from the general public, utilities, and large power users. The lunar mine may be an important application of the NASA's upcoming lunar base.