[[Road Map]] to the [[LiftPort]] [[Space Elevator]] 
[[version 1.0.1 public beta]] 
 
1. Introduction 


[[LiftPort]]'s [[mission]] is to -provide [[cheap]], [[safe]] and [[reliable]] [[access to space]]- . We believe that the space elevator will enable such access. A few space elevator [[feasibility studies]] and [[preliminary designs]] have already been performed by different groups. These studies have generally suggested a space elevator consisting of a wide, thin [[ribbon]] anchored to an equatorial, ocean-based station (what we call [[The LiftPort]]) on one end and connected on the other end to a [[counterweight]] roughly 100,000km up in space. The ribbon is climbed by [[lifter]] vehicles which are [[powered from the ground]] by [[lasers]]. The [[technical road map]] presented here is based on this design, although any [[system architecture]] changes made in the next few years will not significantly change the total [[timeframe]] or [[budget]].  This roadmap is an outline of the [[major tests]] and [[demonstrations]] that must be performed (whether by LiftPort or others) for [[technical]], [[legal]], and [[political]] reasons before the space elevator can be built. While we have considered many [[non-technical milestones]], that side of the space elevator has not been developed enough to be able to outline the required steps with much confidence. The space elevator project will be one of the greatest engineering projects in the history of mankind. The largest obstacle to building it is the [[high-strength]], [[low-weight]] [[material]] needed to make an [[economically feasible]] space elevator.  Although more is always better in the case of [[material strength]], we are basing the road map on a [["minimum"]] [[specific strength]] that is roughly 15 times better than the best current materials. [[Carbon nanotubes]] ([[CNT]]'s) have shown promise in lab experiments to meet this requirement, but to scale up from microscopic [[lab samples]] to [[industrial material production]] is a development process which will take years. The rate of development of the carbon nanotube material greatly affects the timeframe in which the space elevator can be built. While some skeptics believe that the requisite material will not be developed in the next century, other optimists think a breakthrough will happen within the next few years. Our view is somewhere in the middle; we speculate that the necessary material will be available around 2020, making [[commercial operation]] of the first space elevator possible by the year [[2031]] if there is adequate funding and no major [[developmental setbacks]].  This [[timeline]] will obviously slip if the material advancement takes longer.  Unfortunately, the [[completion date]] will not happen much earlier even if the requisite material were available in bulk quantities right now.  [[Research and development]] of the numerous other [[required technologies]] should begin as soon as possible, though, for two reasons.  First, there is an enormous amount of work to be done in areas other than the ribbon material.  Second, the [[spin-offs]] from these [[research fields]] will be of great value [[whether or not the space elevator is ever built]]. [[Global awareness]] of the space elevator concept and its perceived feasibility is still low.  In order to clarify some of the [[steps]] that need to be taken before this revolutionary method of space access can be built, we are publishing the attached road map.  There is a one page [[schematic overview]], as well as a three-page [[Gantt chart]] for those interested in more details.  Aspects of this road map are [[subject to debate]], and we [[expect input]] from various quarters will enable us to [[revise]] the road map and [[update]] the time estimates. The perceived feasibility of the space elevator can be improved if a [[diverse]], [[coordinated]], and global group of [[interested parties]] pursues the large amount of preparatory research required.  Like other companies working in emerging fields, LiftPort has pursued [[partnerships]] with researchers in [[academia]], [[government]] and [[industry]] to advance the [[state of knowledge]].  But the space elevator is [[larger than any single company]].  We at LiftPort want to promote an [[open approach]] to space elevator development, especially because it is an exciting project for [[students]] and [[researchers]] to get involved in.  To encourage people [[around the world]] to learn more and to [[contribute]] to the growing body of [[public knowledge]], -we have created a freely-available online resource containing space elevator-related research problems.  It is available at http://questions.liftport.com-.  -The site and its content are still being developed-, but we encourage [[everyone]] with an interest in the project to [[get involved]].  LiftPort aims to use this site as a way to [[coordinate]] the global research efforts surrounding the space elevator. 


 
2. [[Roadmap Structure]] 
 
[[MATERIAL DEVELOPMENT]] 
Although LiftPort is involved in the [[production]] of carbon nanotubes, we will likely rely on the global development of high strength CNT materials.  While we assume the material will be available around the year 2020, earlier availability will not particularly [[speed up development]] of the space elevator.  The various tests and demonstrations discussed below are dependent on [[three milestones]] of [[increasing material strength]] occurring between now and the year 2020. 

 
[[ACADEMIC]] [[RESEARCH PROJECTS]] 
As one of the largest [[infrastructure]] [[projects]] in history, the space elevator will require a huge [[interdisciplinary]] research effort.  To [[kick-start]] the research, LiftPort is hosting a [[public]] [[online resource]] containing space elevator related [[research problems]], -now available at http://questions.liftport.com.  The site is new as of October 2006,- and we encourage you to browse through the [[questions]], to [[tackle]] any that are of interest, and to [[contribute]] [[new questions]].  We hope that this resource will [[inspire]] researchers to expand their own related projects to [[help]] address [[questions of importance]] to space elevator development.  The [[questions database]] should provide the focus for [[near-term]] [[academic research]].  Topics will include [[high-resolution]] [[laser]] [[focus]] & [[tracking]], [[ribbon dynamics]], evaluating & addressing [[physical threats]],[[preliminary designs]] of [[major components]], as well as addressing [[legal]] and [[business]] issues.  The research will encompass not only [[paper]] [[analysis]], but [[laboratory]] [[experiments]] as well. 

 
[[ATMOSPHERIC RESEARCH]] 
[[Tethered]] [[high-altitude]] balloons allow us to investigate many aspects of space elevator [[operations]] without the expense of [[space-based tests]].  In fact, [[LiftPort]] has already begun work in this area with a [[1.6km]] altitude test and a [[2 month]] endurance test of balloon systems.  Next, a series of three progressively higher balloon-lofted ribbon tests will be used to evaluate multiple [[issues]].  The first test, to an altitude of [[3km]], will demonstrate basic [[ribbon dynamics]] and [[control]] as well as a [[prototype]] [[lifter]] vehicle.  A second test to [[10km]] will examine operation of the [[lifter]] vehicle in varying [[atmospheric conditions]], [[ribbon behavior]] and [[spooling control]], as well as [[weather effects]] on the [[ribbon]].  The third test, aiming to reach an altitude of [[30km]] or more, will continue the investigations from the 10km test and also test [[power beaming]] to an improved [[lifter]] vehicle prototype. 

 
ORBITAL RESEARCH 
The longest tether ever deployed in space was roughly 20km long.  Given the history of problems in tether experiments, it would be imprudent and impractical (at best) to go immedi-ately to a 100,000km system.  In addition, much can be learned by smaller scale tether design experiments before the final carbon nanotube-based ribbon material is available.  The plan to address all the necessary orbital research minimizes the number of launches because launching space-based tests is currently expensive (a fact which the space elevator is intended to remedy).  First, a retired satellite will be used to test tracking and focus of laser power beaming from the ground.  At about the same time, the first of a series of three increasingly longer tether deployment missions will go significantly beyond current experience, deploying a 200km-long tether.  Next will come a 2,500km-long tether.  Both of the tether tests will demonstrate ribbon deployment & control, and debris-dodging ability for a pre-touchdown ribbon.  The third tether mission will be roughly 30,000km long.  The bottom of this tether will be a few hundred kilometers above the altitude at which GPS satellites orbit, enabling safe demonstration of the ability to dodge satellites.  A lifter vehicle traversing the ribbon will be powered remotely by laser, demonstrating an integrated system operating in orbit.  Last, an orbital material exposure facility will validate the combined effects of the orbital environment on the final ribbon material. 

 
SPACE ELEVATOR COMPONENT DESIGN 
After the necessary research is performed, a detailed engineering design of the components of the space elevator can begin.  Designing, prototyping, testing and fabricating the anchor station, lifter vehicle, power beaming system, and counterweight will entail large teams working for many years. 

 
SPACE ELEVATOR DEPLOYMENT 
Once all designs are finished and all components have been produced, the space elevator will be assembled, launched and deployed.  Once the initial ‚ ¨ Sseed‚ ¨ù ribbon is in place, the system will bootstrap itself by lifting new ribbon into orbit and adding it to the initial ribbon.  This process will take at least 16 months to scale the ribbon up to a commercially useful capacity.  When it is completed, the space elevator will enable high-capacity, low-cost cargo transportation to Earth orbit and beyond. 

 
3. Road Map Schematic 
A schematic overview of the road map is on the next page.  This diagram gives a rough idea as to the physical regimes in which various system demonstrations will take place, as well as the time required. For more details, including dependencies between the elements, please see the three-page Gantt chart that follows the schematic.  Each activity was set to occur as early as possible, limited only by dependencies on the completion of other activities.  

 
4. Credits 
The LiftPort space elevator road map was developed by Tom Nugent, Jasper Bouwmeester, Michael Laine, and Mannix Shinn.  We are very thankful for the valuable input and feedback provided by Jordin Kare, Robert Hoyt, and Robert Carlson.