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<tr><td colspan="3" align="center" style="background-color:#CCCCCC"><b>Title:</b> Integration</td></tr>

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<b>About:</b><br />
* Moderator: [[Integration#edwards|Brad Edwards]]<br />
* Created: July 6, 2008<br />
* Modified: July 25, 2008<br />
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'''[[Article Tags|Tags]]''':<br />
* This is a collaborative article<br />
* Discipline(s): Wiki, Engineering
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__TOC__
<div style='clear:right'>&nbsp;</div>

== Integration ==


Building the individual components of a system can be easy until they have to fit and work together.  The integration of the space elevator is actually more simple than might be expected but it is still complex.  Below is the basic interaction matrix for the space elevator.  This matrix drives decisions across the effort but in the form here is still incomplete and crude in terms of its static nature.  The goal is to get this matrix interactive and constantly upgraded to include all aspects of the elevator interactions.


== Additional Work Needed == 

<issues/>

== Space Elevator Interaction Matrix ==



{| border="1" cellpadding="2"
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|-
| System||   Component||   Subcomponent||   Affected component||   Implications
|-
|  style="background:yellow" | Ribbon||   Material||   Strength||   Cost||   Higher strength material will be more costly to develop and produce.  The trade needs to be between required strength and cost.
|-
|  ||   ||   ||   ||   Higher strenth material may mean a lower mass overall ribbon, fewer construction climbers and less repairs all which reduce cost
|-
|  ||   ||   ||   Ribbon||   Higher strength material implies higher operating tension and higher stored energy in the stretched material.  Mitigation of catastrophic failure of CNT threads under extreme tension requires detailed small-scale design and testing.
|-
|  ||   ||   ||   ||   Ribbon taper and overall mass are inversely propotional to strength.
|-
|  ||   ||   ||   Risk||   Lower strength equates to increased risk due to lower safety factor.
|-
|  ||   ||   ||   ||   Lower strength also relates to higher perceived risk of construction.
|-
|  ||   ||   Surface||   Climber||   A low friction ribbon surface means more challenges in the friction drive
|-
|  ||   ||   ||   ||   A metalized surface will need repair and maintainence by the climbers.
|-
|  ||   Small-Scale Design||   Interconnect||   Risk||   Fewer interconnects results in higher risk
|-
|  ||   ||   ||   ||   Wider interconnects are stiffer allowing less sliding of threads and possibly creating high stress spots
|-
|  ||   ||   ||   ||   Narrower interconnects allow for more thread sliding and equlibration over long distances they also allow damage to interact across multiple segments
|-
|  ||   ||   ||   ||   Tape sandwiches allow tension release from threads, easy splicing,... but can degrade 
|-
|  ||   ||   ||   ||   Woven CNT interconnects will be as resilient to the environment as the rest of the ribbon, can lock on or slide on threads as desired, more difficult to splice
|-
|  ||   ||   ||   ||   Sliding interconnects allow for slow and consistent tension redistribution reducing tearing and catastrophic degradation of axial fibers.
|-
|  ||   ||   ||   Ribbon||   More interconnects results in higher overall ribbon mass
|-
|  ||   ||   ||   Climber||   More interconnects means higher splicing speed by climber and more mass to carry
|-
|  ||   ||   Fiber size||   Cost||   Smaller fibers require more production time and processing time to convert into a ribbon.  This converts into a more expensive ribbon.
|-
|  ||   ||   ||   Ribbon ||   Smaller fibers imply easier attachment by interconnects and less separation lengths between fibers.
|-
|  ||   ||   ||   Climber||   Smaller fibers provide more surface area to grab but also more fragile fibers
|-
|  ||   Large-Scale Design||   Length||   Operations||   Destinations: at 100,000 km the ribbon can throw to Venus and Asteroids, at 119,000 km Jupiter is reachable 
|-
|  ||   ||   ||   Overall Design||   The longer the ribbon the smaller the counterweight required.  At 144,000km length the counterweight mass goes to zero.
|-
|  ||   ||   ||   Climber||   The longer the ribbon the smaller the useful climber for deployment that can be utilized at the upper end as a counterweight.
|-
|  ||   ||   Taper||   Climber||   Higher taper ratio means lower ribbon capacity and smaller climbers.  Climbers must move faster to build up the ribbon in a safe timeframe.
|-
|  ||   ||   ||   Ribbon||   Higher taper ratio means heavier ribbons for the same capacity.
|-
|  ||   ||   ||   ||   Low taper ratio means higher material strength required or lower safety margin
|-
|  ||   ||   ||   Risk||   Higher taper ratio provides higher safety factor to survive more damage
|-
|  ||   ||   ||   Cost||   The higher the taper ratio the higher the overall construction mass and cost
|-
|  ||   ||   Mass||   Operations||   Higher mass means more rockets and climbers to build.
|-
|  ||   ||   ||   Cost||   Higher mass means more expensive ribbon and deployment.
|-
|  ||   ||   ||   Schedule||   Higher mass ribbon takes longer to deploy.
|-
|  ||   Variations||   LEO Width Increased||   Risk||   Wider ribbon will reduce risk of damage due to LEO objects
|-
|  ||   ||   ||   ||   Wider ribbon will increase possible damage by climber due to thickness.
|-
|  ||   ||   ||   Climber||   Must deal with wider ribbon
|-
|  ||   ||   ||   Mass||   Wider ribbon will have a larger percentage of interconnect mass and thus larger overall mass. 
|-
|  ||   ||   Smaller Width in Atm.||   Risk||   Narrower ribbon will reduce the risk of damage from wind
|-
|  ||   ||   ||   Climber||   Thinner width will be challenge for climber to clamp.
|-
|  ||   ||   Thick vs Wide||   Risk||   Probability of impact from orbital debris and micrometeorites is higher with wider ribbons though wider ribbons can survive larger and more impacts. The wider the better from a risk standpoint.
|-
|  ||   ||   ||   Climber||   It is more difficult for climber to adjust to variable width than variable thickness
|-
|  ||   Coatings||   Characteristics||   Risk||   Damage to the coatings will reduce their effectiveness
|-
|  ||   ||   ||   ||   Coatings will reduce damage by hazards such as atomic oxygen. 
|-
|  ||   ||   ||   Climber||   Climbers must produce minimal wear on the ribbon to minimize damage to the coatings.
|-
|  ||   ||   ||   ||   Special climbers required for laying down coatings.
|-
|  ||   ||   ||   ||   Drive systems need to deal with coatings that may have a different coefficient of friction than the ribbon.
|-
|  ||   ||   ||   Ribbon||   Coatings increase the overall mass of the ribbon.
|-
|  ||   ||   ||   ||   Immature technology for coating a CNT ribbon
|-
|  ||   ||   ||   Operations||   Re-coating of the fibers may be required due to wear
|-
|  ||   ||   ||   ||   A coated ribbon may be easier to track with radar
|-
|  ||   Initial Ribbon||   Size||   Risk||   The larger the initial ribbon the more challenging the deployment.  More launches or larger launches are required.
|-
|  ||   ||   ||   ||   The larger the initial ribbon the faster the build-up and lower the risk of fatal damage at early stages
|-
|  ||   ||   ||   Schedule||   The larger the initial ribbon the shorter the deployment schedule - ~6 months for every factor of two in size
|-
|  ||   ||   ||   ||   Deployment of a larger initial ribbon may require a longer up-front development time.
|-
|  ||   ||   ||   Cost||   The larger the size of the initial ribbon the more launches required - linear dependence
|-
|  ||   ||   ||   ||   The larger the initial ribbon the fewer construction climbers required.
|-
|  ||   ||   ||   Climber||   The larger the initial ribbon the larger the initial climber
|-
|  ||   Alternatives||   Tube||   Climber||   Unless rigid (very massive) crimping and pinching will occur.
|-
|  ||   ||   ||   Risk||   High debris damage risk due to smaller frontal area.
|-
|  ||   ||   ||   Ribbon||   Much higher mass for a solid tube than a ribbon of fibers.
|-
|  style="background:yellow" |  Climber||   Velocity Trade||   Constant Power||   Power Beaming||   Power beaming and power receiver on climber are simple - velocities range from < 20mph to >120 mph
|-
|  ||   ||   ||   Climber||   Drive system runs at variable speed through Earth's gravity well
|-
|  ||   ||   Constant Speed||   Power Beaming||   Requires high power at Earth and less as you go up
|-
|  ||   ||   ||   Climber||   Constant speed drive is easier and lighter to gear
|-
|  ||   ||   ||   ||   More complex power system
|-
|  ||   ||   Velocity||   Schedule||   The higher the speed the faster the build up
|-
|  ||   ||   ||   Risk||   Immature technology for speeds above 200 km/h
|-
|  ||   ||   ||   ||   Higher speeds required for safe transport of humans
|-
|  ||   Drive||   Friction: Tread||   Ribbon||   Flat ribbon design required
|-
|  ||   ||   ||   ||   Designed to survive tread transit
|-
|  ||   ||   ||   ||   Tread must account for contraction of ribbon during transit - if climber is at the limit of mass then the contraction could be 1 - 10%
|-
|  ||   ||   ||   ||   Tread has low pressure on ribbon - pressure is linear with tread area
|-
|  ||   ||   ||   ||   Tread must center ribbon - passive centering is preferred
|-
|  ||   ||   ||   Climber||   Simple, mature technology
|-
|  ||   ||   ||   Risk||   Minimal wear and tear on ribbon
|-
|  ||   ||   ||   ||   Reduced efficiency due to bending of tread
|-
|  ||   ||   ||   Schedule||   Limited velocity implies slower delivery schedule to orbit
|-
|  ||   ||   Friction: Roller||   Ribbon||   Flat ribbon design
|-
|  ||   ||   ||   ||   Bending over rollers wears ribbon
|-
|  ||   ||   ||   ||   Higher pressure on ribbon than tread design
|-
|  ||   ||   ||   ||   Ribbon/rollers must work together to center
|-
|  ||   ||   ||   Climber||   Simple, mature technology
|-
|  ||   ||   ||   Risk||   Increased wear and tear on ribbon and rollers
|-
|  ||   ||   ||   Schedule||   Limited velocity implies slower delivery schedule to orbit
|-
|  ||   ||   Magnetic||   Ribbon||   Very massive ribbon required due to wiring.
|-
|  ||   ||   ||   Risk||   Immature technology
|-
|  ||   ||   ||   Operations||   High-speed transport could allow higher performance.
|-
|  ||   ||   ||   Cost||   Very high due to ribbon mass and risk.
|-
|  ||   Payload||   ||   Operations||   Payload handling affects overall operations 
|-
|  ||   ||   ||   Climber||   Larger payload requires larger or higher efficiency climbers 
|-
|  ||   ||   ||   ||   Lower risk climbers required for human transport
|-
|  ||   Splicing||   Side-by-side||   Risk||   Immature technology 
|-
|  ||   ||   ||   Ribbon||   Overlap, width, thickness and spacing affect ribbon mass
|-
|  ||   ||   ||   ||   Engineered slippage above a certain tension enables debris and meteor survivability.  Too rigid of grip induces tears, too loose and the affected length of ribbon becomes long.
|-
|  ||   ||   ||   ||   Side-by-side splicing implies a full-length narrow ribbon – size can be limited by available thread size and interconnect design.
|-
|  ||   ||   ||   Climber||   Must be able to splice reliably at 10Hz.
|-
|  ||   ||   ||   ||   Splicing must be done under tension.
|-
|  ||   ||   End-to-end||   Deployment||   Requires deployment of full width and full mass ribbons.
|-
|  ||   ||   ||   ||   Due to taper requirements, deployment must be from the middle under full ribbon tension
|-
|  ||   ||   ||   Cost||   Many large rockets required
|-
|  ||   ||   ||   ||   Few construction climbers required
|-
|  ||   ||   ||   Climbers||   Must be able to deal with joints in the ribbon if used
|-
|  ||   ||   ||   Ribbon||   Joints must be made in place and hold full tension
|-
|  ||   Disposal||   ||   Regulations||   Storage of climbers in orbit could be the subject of regulations
|-
|  ||   ||   ||   Operations||   Disposal or reuse of climbers will impact how the elevator is used
|-
|  ||   ||   ||   Cost||   Cost trade-off of disposal vs. Reuse is complex
|-
|  ||   ||   ||   ||   Use of the climbers for parts in future applications could be a reasonable business model
|-
|  ||   ||   ||   Schedule||   If climbers are to be reused then the elevator will need to be shut down when the climbers are brought back down if a second ribbon is not available
|-
|  ||   Power||   Laser Beamed||   Schedule||   Reasonable power levels will enable 8 day travel from Earth to GEO
|-
|  ||   ||   ||   ||   Multiple climbers utilizing the same power beaming systems will require detailed scheduling
|-
|  ||   ||   ||   Climbers||   Need tracking beacon on climber
|-
|  ||   ||   ||   ||   Power receiver is mature PV technology
|-
|  ||   ||   ||   Operations||   Clouds will reduce power and climber will need to deal with it
|-
|  ||   ||   ||   ||   Shadow of ribbon on PV array could cause issues
|-
|  ||   ||   ||   Power Sys||   PV array needs to supply HV to motors
|-
|  ||   ||   ||   ||   Thermal/mass trades depending on Si or GaAs array
|-
|  ||   ||   ||   Regulations||   High-power laser use will require FAA clearance
|-
|  ||   ||   ||   ||   Issues with reflections off of climber
|-
|  ||   ||   ||   Risk||   Low development risk
|-
|  ||   ||   Beam RF||   Power Sys||   Large receiver 
|-
|  ||   ||   ||   Operations||   Similar receiver and converter to solar array
|-
|  ||   ||   ||   Cost||   Inefficient system increases operations cost
|-
|  ||   ||   ||   Climber||   Large rectenna receiver, possible thermal issue
|-
|  ||   ||   Conducted RF||   Ribbon||   Must be large (10 meters+)
|-
|  ||   ||   ||   Operations||   Powers lower climber only
|-
|  ||   ||   ||   Climber||   RF receiver
|-
|  ||   ||   Conducted Electrical||   Ribbon||   Two conductors with insulator
|-
|  ||   ||   ||   Cost||   Efficiency of transmission drops with distance, at GEO efficiency can be small fractions of a percent
|-
|  ||   ||   ||   Operations||   Difficult to power multiple climbers differently
|-
|  ||   ||   ||   ||   Damaged climber may short conductors 
|-
|  ||   ||   ||   Power Sys||   Simple
|-
|  ||   ||   ||   Risk||   Has single point system failure – damaged ribbon
|-
|  ||   ||   ||   Climber||   Simple, low mass receiver
|-
|  ||   ||   ||   ||   Drives are high resistance to use power efficiently
|-
|  ||   ||   Solar||   Schedule||   Low power delivery slows transit dramatically
|-
|  ||   ||   ||   Risk||   Mature technology
|-
|  ||   ||   ||   ||   Slow deployment with this system implies a longer schedule with a small and vulnerable ribbon
|-
|  ||   ||   ||   Power Sys||   None on Earth, only climber receiver
|-
|  ||   ||   ||   ||   Possible alternative could use reflected solar power form Earth to increase power density
|-
|  ||   ||   ||   Cost||   Increase climber but reduced power beaming costs
|-
|  ||   ||   ||   Operations||   Slowed
|-
|  ||   ||   ||   Climber||   Receiver design is solar arrays with orientation actuators
|-
|  ||   ||   Nuclear||   Schedule||    Risk, cost, personnel protection
|-
|  style="background:yellow" |  Anchor||   Power||   Size||   Cost||   The larger the power system - higher the cost.  
|-
|  ||   ||   ||   Operations||   Larger power systems will require more personnel and more extensive maintenance operations.
|-
|  ||   ||   ||   Power Sys||   The power beaming system size will be limited by the power available on the station.
|-
|  ||   ||   ||   Anchor: Drive||   Larger power systems will allow for larger drives
|-
|  ||   ||   ||   Anchor: Platform||   The larger power systems will require more volume on the platform, more fuel storage.  
|-
|  ||   ||   Fuel||   Operations||   The choice of fuel will drive the operations in terms of delivery, safety, regulations
|-
|  ||   ||   Maintain||   Operations||   Maintenance requirements will determine station l need to go to drydock and thus downtime.
|-
|  ||   Drive||   Mobility||   Operations||   Drive performance determines the anchor’s ability to move the ribbon out of the path of satellites and storms. 
|-
|  ||   ||   ||   ||   Mobility also enables the anchor to travel to drydock for maintenance.  Higher speed and mobility means less down time.
|-
|  ||   ||   ||   Ribbon||   The greater mobility reduces the number of collisions with the ribbon and reduces the required robustness of the ribbon
|-
|  ||   ||   ||   Cost||   The better the drive the higher the cost.  
|-
|  ||   ||   ||   ||   The reliability and lifetime affects the cost.  
|-
|  ||   ||   ||   ||   The fuel used in the drive will impact the operations cost.
|-
|  ||   ||   ||   Risk||   Mobility of the anchor reduces the risk from debris and storms.
|-
|  ||   ||   Size||   Risk||   The larger the drive the more quickly the anchor can respond to requests to move.
|-
|  ||   ||   Accuracy||   Tracking||   The accuracy of the drive enables use of higher accuracy tracking.
|-
|  ||   ||   ||   Risk||   The accuracy of the drive reduces of the possibility of impact by debris.
|-
|  ||   ||   ||   Anchor||   The anchor station will need to be equipped with the GPS and other navigation tools 
|-
|  ||   Platform||   Size||   Power Sys||   The size of the platform can limit the use of RF and FEL power beaming systems due to their required footprint.  For FEL a length of about 150 m is required.  Solid-state lasers require less footprint.
|-
|  ||   ||   Stability||   Power Sys||   A stable platform reduces the need for a optics system that can track the climber over degrees continuous on a fast timescale.  The lower stability platform will result in higher power system and maintenance costs.
|-
|  ||   ||   Robustness||   Operations||   Robustness implies longer time between maintenance in drydock. Less-expensive operations.
|-
|  ||   ||   Design||   Schedule||   A better design for the platform including high-quality housing and recreation on the platform will reduce the schedule impacts due to the workforce needs to have time away.
|-
|  ||   ||   ||   Risk||   A better design for the platform will reduce the stress of the workers and improve their performance.
|-
|  ||   Attachment||   Mobility||   Operations||   Required removability for transfer between anchor stations for repair and general drydock.
|-
|  ||   ||   Robustness||   Cost||   Less repair and down time with greater robustness.
|-
|  ||   ||   Capability||   Operations||   The reeling in and out as well as proper tensioning is required for proper and safe operation.
|-
|  ||   ||   ||   Risk||   The capability of the attachment will enable reeling in and out of the ribbon as well as properly maintaining the tension on the ribbon.  Propoer execution of these operations will reduce the overall risk.  
|-
|  ||   ||   ||   ||   Being able to reel in the ribbon to deal with malfunctioning climbers also reduces risk.
|-
|  ||   Location||   E. Equat Pacific.||   Risk||   This location was selected to minimize risk from the weather.
|-
|  ||   ||   ||   Operations||   This location in the middle of nowhere impacts operations by making the trip to and from the anchor long and more costly.  Maintenance and repair of the anchor require long travel distances or repair at sea.
|-
|  ||   ||   ||   ||   The extremely mild weather at this location makes operations easy in terms of maintaining location, stability and weather damage.
|-
|  ||   ||   ||   Anchor||   The anchor must be very reliable due to the remote location.
|-
|  ||   ||   ||   Cost||   The cost of construction of the anchor for this location is less than for other locations but the general operations will be more costly due to the remote location.
|-
|  ||   ||   Australia||   Politics||   US politics will not be happy with foreign ownership
|-
|  ||   ||   ||   ||   Associated with friendly country
|-
|  ||   ||   ||   ||   Near volatile countries such as Indonesia
|-
|  ||   ||   ||   Operations||   Possibly close to major cities
|-
|  ||   ||   ||   ||   Ribbon goes up at an angle
|-
|  ||   ||   ||   Risk||   More lightning
|-
|  ||   ||   ||   Cost||   Funding can be split 
|-
|  ||   ||   Land||   Operations||   Movement on land is more difficult
|-
|  ||   ||   ||   ||   Easy access for cargo and people
|-
|  ||   ||   ||   ||   Plenty of room for people to live and facilities
|-
|  ||   ||   ||   Risk||   Lightning is more prevalent
|-
|  ||   ||   ||   ||   Easy access for terrorists
|-
|  ||   ||   ||   Anchor||   No anchor station
|-
|  ||   ||   General||   Operations||   GEO location slots may be filled - may need to locate south of Equator
|-
|  ||   Alternatives||   Multiple Legs||   Anchor||   Multiple stations need to be coordinated to maintain tension
|-
|  ||   ||   ||   ||   More anchor maintenance due to larger number of anchors
|-
|  ||   ||   ||   Ribbon||   Redundant ribbons at bottom mean additional mass though each leg can only support the same climber
|-
|  ||   ||   ||   ||   Dynamics are different than single leg and not well understood
|-
|  ||   ||   ||   ||   Dynamics of the loss of a single leg are not understood 
|-
|  ||   ||   ||   ||   Attachment point needs to be able to add and replace legs
|-
|  ||   ||   ||   ||   Attachment point needs to hold the tension for all
|-
|  ||   ||   ||   ||   Added mass of attachment and legs comes out of climber/payload mass
|-
|  ||   ||   ||   Climber||   Climber must be able to ascend one leg, cross attachment point and continue up
|-
|  ||   ||   ||   ||   Smaller climber for same primary ribbon
|-
|  ||   ||   ||   ||   Climbs at an angle
|-
|  ||   ||   ||   Operations||   More available integration time for attaching climbers to leg ribbon (~time for 1 leg *#of legs)
|-
|  ||   ||   ||   ||   Coordinating climbers from different legs is required
|-
|  ||   ||   ||   ||   Deployment is more complex, attaching legs
|-
|  ||   ||   ||   Power Sys||   Possibly more, smaller beaming stations - each associated with a leg
|-
|  ||   ||   ||   Risk||   Redundant legs reduce risk of loss at low altitudes
|-
|  ||   ||   ||   ||   Risk of attachment failure
|-
|  ||   ||   ||   Cost||   Additional anchors adda cost
|-
|  ||   ||   ||   ||   Anchor maintenance adds cost
|-
|  ||   ||   ||   ||   Attachment point adds cost in development and operations
|-
|  ||   ||   ||   ||   Additional ribbon complexity adds cost
|-
|  ||   ||   ||   ||   Additional power beaming systems add cost
|-
|  style="background:yellow" |  Power Beaming||   Laser||   FEL||   Size||   Requires large platform
|-
|  ||   ||   ||   Location||   Line of sight, no clouds
|-
|  ||   ||   ||   Anchor||   Efficiency requires more power
|-
|  ||   ||   ||   Operations||   Complex system
|-
|  ||   ||   ||   Regulations||   Restrictions on open high-powered lasers near people, airplanes, etc.
|-
|  ||   ||   Solid-State||   Cost||   $100/W capital cost
|-
|  ||   ||   ||   ||   Major replacement of pump diodes every five years
|-
|  ||   ||   ||   Power Beaming||   30% wall plug efficiency determines power required
|-
|  ||   ||   ||   ||   No need for large station to expand beam
|-
|  ||   ||   ||   Risk||   Megawatt laser power can damage airplanes, animals and nearby humans
|-
|  ||   ||   ||   ||   1KW laser module has been built, current program pushing to build 100kw and believe MW laser possible - may need to couple lasers and consider 10-20% duty cycle for coupling
|-
|  ||   ||   ||   Operation||   500 microsec pulse, 10-20% duty cycle
|-
|  ||   ||   ||   ||   Easy operation, maintenance
|-
|  ||   ||   ||   ||   Transportable in small container
|-
|  ||   ||   ||   ||   Line of sight with climber required – no clouds
|-
|  ||   ||   ||   ||   Replacement required at regular intervals
|-
|  ||   ||   ||   ||   No expendables
|-
|  ||   ||   ||   Climber||   Wavelengths of 810 to 990 nm, receivers can be GaAs or Si depending on laser design
|-
|  ||   ||   ||   ||   Si receivers would imply a possible thermal issue
|-
|  ||   ||   ||   ||   High quality beam allows for small receiver diameter
|-
|  ||   ||   ||   Deployment||   Small laser modules implies easy delivery to stations
|-
|  ||   ||   ||   ||   Small laser modules imply easy dispersion to global locations for use during deployment and then relocation for standard operations
|-
|  ||   ||   Primary Optics||   Mirror||   Heat and pointing issues
|-
|  ||   ||   Operations||   Climber||   Required tracking becon
|-
|  ||   ||   ||   ||   Require proper PV arrays
|-
|  ||   Beam RF||   Antenna||   Climber||   Large receiver
|-
|  ||   ||   Cycle Time||   Operations||   Transmitter is not movable, line of sight, no clouds, near power plant
|-
|  ||   ||   ||   Cost||   Inefficient power delivery, very large transmitter, additional power plants
|-
|  ||   ||   ITU||   Regulations||   Restrictions on beamed power and safety
|-
|  ||   Conducted RF||   ||   Ribbon||   Metal coated
|-
|  ||   ||   ||   Climber||   RF receiver
|-
|  ||   ||   ||   Operations||   Multiple climbers?
|-
|  ||   Conducted Electrical||   Design||   Ribbon||   Dual conductors with insulator between  Increases mass of ribbon dramatically
|-
|  ||   ||   ||   Power  system||   High transmission losses
|-
|  ||   ||   Coupling||   Climber||   High resistance motors required
|-
|  ||   ||   Ground||   Anchor||   Power at anchor
|-
|  ||   ||   Damage||   Operations||   Multiple climbers?
|-
|  ||   ||   ||   Risk||   A ribbon sever could cut power, lightning rod
|-
|  ||   Locations||   Deployment||   Regulations||   During deployment it will be useful for the power stations to be located at widely spaced locations on Earth.  This will require international cooperation.
|-
|  ||   ||   ||   Anchor||   The anchors may need to be mobile if they need to be at different locations during deployment and operations.
|-
|  style="background:yellow" |  Deployment Satellite||   Initial Ribbon||   Size||   Risk||   The larger the ribbon the less the risk of damage and destruction - exponential improvement.
|-
|  ||   ||   ||   Schedule||   The larger the ribbon the shorter the schedule - linear dependence.
|-
|  ||   ||   ||   Climber||   The larger the ribbon the larger the initial climber - linear dependence
|-
|  ||   ||   ||   Spacecraft||   The larger ribbon requires a larger support system and size is limited by the capabilities of the launch vehicles available - structure is linear dependence, fuel is exponential increase with ribbon size.
|-
|  ||   ||   Spooling||   Ribbon||   Spooling determines the ribbon design, width, flexibility required, and the risk of twisting and tangling.
|-
|  ||   ||   ||   Spacecraft||   Combining spools - End or side unspooling
|-
|  ||   Propulsion||   Electric||   Power Sys||   The electric propulsion requires high powers.  This power can be supplied by the power beaming but it will impact the design of the power beaming system.  Tracking, scheduling and location of the power beaming system will be the main considerations.
|-
|  ||   ||   ||   Schedule||   The electric propulsion will require a much longer time (6 months to years) to move the spacecraft from LEO to GEO.  A solid rocket engine would do the move in days.
|-
|  ||   ||   ||   Risk||   Development risk - Longer SC operation - longer time in radiation belt
|-
|  ||   ||   ||   Ribbon||   Due to the higher efficiency and lower fuel mass a larger initial ribbon can be deployed
|-
|  ||   ||   ||   Spacecraft||   Reduced structure requirements
|-
|  ||   ||   Chemical||   Ribbon||   A smaller initial ribbon can be deployed with the same launchers than for electric propulsion.
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|  ||   ||   ||   Schedule||   Faster move from LEO to GEO
|-
|  ||   ||   ||   Risk||   Low development risk - shorter SC operating time - less time in radiation belts
|-
|  ||   ||   ||   Spacecraft||   Heavier structures for fuel - exponential growth
|-
|  ||   Power System||   Nuclear||   Regulatory||   Extensive regulatory requirements
|-
|  ||   ||   ||   Launch||   Limits on launch
|-
|  ||   ||   ||   Cost||   Expensive in direct and indirect costs
|-
|  ||   ||   ||   Spacecraft||   Can be used for electric propulsion
|-
|  ||   ||   Beamed||   Power Sys||   Simple, mature technology
|-
|  ||   ||   ||   ||   Lightweight system
|-
|  ||   ||   ||   Schedule||   Less than 100% duty cycle will increase schedule
|-
|  ||   ||   ||   Risk||    Powerful lasers located at different locations – both technology transfer and safety risk.
|-
|  ||   ||   ||   Spacecraft||   Must operate in low-Earth orbit with <100% duty cycle
|-
|  ||   ||   ||   ||   Must orient to the laser power beaming
|-
|  ||   On-Orbit Assembly||   ||   Cost||   Manned on-orbit assembly is likely to be much more expensive in current environment
|-
|  ||   ||   ||   Schedule||   Manned assembly has much higher schedule uncertainty
|-
|  ||   ||   ||   Spacecraft||   Autonomous assembly is more complex
|-
|  ||   ||   ||   ||   Manned assembly more expensive but less risk
|-
|  ||   Deployment Altitude||   ||   Schedule||   Optimal altitude reduces the deployment schedule
|-
|  style="background:yellow" |  Challenges||   International||   International Consortium||   Operations||   Fewer countries and entities to protest operations.  
|-
|  ||   ||   ||   ||   Stronger alliance to support and protect the anchor.  
|-
|  ||   ||   ||   ||   Stronger alliance to address space treaties
|-
|  ||   ||   ||   Schedule||   All activities must be coordinated with the consortium members
|-
|  ||   ||   ||   Cost||   Int. Consortiums cost more due to interactions and utilizing less capable manufacturers.
|-
|  ||   ||   ||   ||   More entities to spread the cost and risk among
|-
|  ||   Military||   Protection||   Risk||   Reduce the risk of terrorist attack
|-
|  ||   Satellite Debris||   Prob. Of Collision||   Ribbon||   Modification of ribbon dimensions to optimize survivability
|-
|  ||   ||   Movement||   Operations||   Active avoidance, maintenance, 
|-
|  ||   Atomic Ox||   Surface||   Ribbon||   Coat the ribbon or design the ribbon to survive
|-
|  ||   ||   ||   Operations||   Repair and maintenance
|-
|  ||   Radiation||   Lifetime||   Ribbon||   Design to survive radiation, mods may increase size of ribbon
|-
|  ||   ||   Climber||   Structure ||   Increased speed and shielding required for transporting people
|-
|  ||   Oscillation||   Dynamics||   Ribbon||   The taper length and mass determine the natural period of the ribbon, modification of the dimensions will change the frequency of the oscillations.  
|-
|  ||   ||   ||   Operations||   Active damping of oscillations may be required
|-
|  ||   Lightning||   Multiple Legs||   Anchor||   Location requirements
|-
|  ||   ||   ||   Ribbon||   Conductive or non-conductive
|-
|  ||   Wind||   Shape||   Ribbon||   Narrower and thick inside atmosphere
|-
|  ||   ||   Wave Height||   Anchor||   Locate where minimal winds
|-
|  ||   Jet Streams||   Constant||   Anchor||   Locate where minimal jet streams
|-
|  ||   ||   Altitude Vary||   Ribbon||   Minimize cross-section at level of high altitude winds
|-
|  ||   Hurricane||   Winds||   Anchor||   Locate out of hurricane zones
|-
|  ||   Induced Currents||   ||   Ribbon||   Conductive/non-conductive sections to reduce the overall charging and currents
|-
|  ||   Satellite/Debris||   Power||   Ribbon||   Modification of ribbon dimensions to optimize survival
|-
|  ||   ||   Ribbon position||   Operations||   
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|  style="background:yellow" |  Debris Tracking||   Sensors||   Optical||   Cost||   New system to be developed
|-
|  ||   ||   ||   Risk||   Increased development risk
|-
|  ||   ||   ||   ||   Better tracking reduces operations risk
|-
|  ||   ||   Radar||   Cost||   Mature system in use
|-
|  ||   ||   ||   Risk||   Lower accuracy increases risk
|-
|  ||   ||   Accuracy||   Risk||   Lower accuracy increases risk
|-
|  ||   ||   ||   Cost||   Higher accuracy implies higher construction and operations cost
|-
|  ||   ||   Sensitivity||   Risk||   Lower sensitivity means lower performance and high risk
|-
|  ||   ||   ||   Cost||    Higher sensitivity means higher cost in construction and operations
|-
|  ||   ||   ||   Ribbon||   Low sensitivity means impacts on ribbon from small objects, the ribbon must be more resilient
|}

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