SpaceElevatorPower

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Title: Power Delivery

[Cover Img]

About:

  • Moderator: Brad Edwards
  • Created: July 6, 2008
  • Modified: July 25, 2008

Tags:

  • This is a collaborative article
  • Discipline(s): Wiki, Engineering

Contents

 

Power Beaming System

Power is needed for everything and effective delivery over 10's of thousands of kilometers is not easy. Various methods were examined and laser power beaming was selected for the baseline. This is a mature yet still rapidly evolving technology.

Value Details
Power input 20 - 150 MW Can be from any conventional source. Ocean going platforms can have this amount of power available from diesel engines. Spreadsheet on energy needed for ascent File:Energy worksht.ods
Power in laser beam 2 - 15 MW This power does not need to be in a single beam but can come from multiple beams interlaced in time (pulsed beams)
Primary Optics Segmented adaptive optics mirror similar to those in major astronomical observatories
Primary Beam diameter 10-30 meters This size is determined by the focusing required and to reduce the intensity to a relatively safe level.
Wavelength TBD nm To be matched to the type of cells and lasers available.
Tracking accuracy TBD mrad Determined by laser beam and receiver sizes.
Power source Solid-state disk laser Stacked diodes are also coming on line. See File:Ultrahigh-Average Power Solid-State Laser.pdf, File:MCDL LASE 2004 1f.pdf, File:LASE 2004 SSDL 2k final.pdf

Status

Boeing has demonstrated operation of a 25kW laser of the kind we need and claim they can build MW lasers Beaming 9+kW lasers over short distances are to be demonstrated at the Spaceward Space Elevator Games Adaptive optics have been demonstrated with long distance capabilities

Include images and videos from the SE Games Include design write-ups

Delivering power over the distance of the elevator is a challenge but quickly being addressed by current technology.

Major Design Challenges

Additional Work Needed

Item Notes Completed and Ongoing Efforts
Categorize the available laser systems The baseline power delivery system uses a set of high-power lasers to sent power up to a climber ascending the ribbon. Lasers have evolved dramatically over the last 10 years from few large system primarily chemical to now a growing availability of FEL and solid-state systems. With the current rate of change of the solid state systems high power system of the size required will be ready before we are ready to build the elevator. We need someone to evaluate the different lasers keeping in mind the capital and operational cost, overall efficiency of the laser, efficiency of the matching receivers, operational lifetime, laser size and options for combining beams (in time for pulsed systems, what losses with CW systems), weather considerations,...
Detail optics system Although it has been mentioned, it probably unlikely that we can point a laser directly up and deliver the laser power to a 10m diameter spot 10,000 km away - we will likely need optics. What we need someone to do is research the possible large optical system (astronomical telescopes) and get a full rundown on what they will do and what are the challenges for us. We need to know what it takes to get a large laser beam into the optics, what stability is needed, are there issues with operating this in a sea-spray environment, cost, complexity, ...
Weather concerns for the power beaming Initial studies of the selected anchor location show minimal clouds, minimal lightning, minimal wind,... what other issues are there for the power systems being considered. What is the down time that we can expect and realistically see. We need someone to start pulling this together. We also need evaluations of other proposed sites such as those prposed by Phil Ragan off Australia and the Japanese in the Western Pacific or off the Maldives
Safety issues with high power laser High power lasers can cause damage and injure people. We need to be able to operate this system safely and the question is how. Does everyone on the station need to be indoors behind closed windows? or is there a scenario where a live person might actually be able to look at an ascending climber?

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