Analysis of Liftport’s Space Elevator Roadmap
A few days ago Liftport released a document titled “Road Map to the LiftPort Space Elevator”. The document is written to be a plan to develop the space elevator. It is a good idea to assemble the components for the space elevator that have been developed into a publicly available roadmap. This will help people understand and get involved in the effort. Unfortunately, the Liftport roadmap has little relevance to the space elevator development effort as a whole. Liftport apparently has not read or understood the literature on the space elevator and had no input from technical experts on the space elevator or large space or civil projects.
The team that compiled this roadmap consisted of: Michael Laine who has no technical background, Tom Nugent is a recent graduate with limited experience on the space elevator, and two student interns at Liftport. The three people they list as having supplied helpful input have extremely limited involvement in the space elevator development and have their own competing concepts. A video posted on the web shows Michael Laine, one of the authors of the document, giving a talk on the elevator (my old video playing the background) where he states he doesn’t know how the components work so don’t embarrass him by asking.
The major pitfalls of this roadmap include but are not limited to:
At the end of August an announcement came out from Los Alamos National Laboratory stating they had produced material 100 times stronger than steel (pound for pound). This is about 50GPa or about 15 times Kevlar, Vectran or Spectran. Efforts to produce large commercial quantities of material with these characteristics are underway. Liftport has this material strength milestone at the year 2020 and this drives much of their roadmap.
The laser tracking test in the roadmap listed for completion the end of 2009 were completed about ten years ago out of the Starfire Range in New Mexico and laser tracking and ranging have been done since the early 1970’s. These results have been referenced in several prominent space elevator documents.
Much of the finite element analysis proposed to be finished by 2010 has been done. This work covers deployment, wind loading, oscillations, ribbon breakage, climber traverse and all the details associated with these (David Lang, ISDC 2006).
The balloon tethers have very limited use but play a large role in the Liftport roadmap. In the form that Liftport has been doing these, with batteries, the experiments have practically no value. The small climbers with batteries do not lead to a viable space elevator climber. Whereas, the much larger and better development efforts resulting from the NASA-sponsored climber challenge will produce climbers demonstrating the climbing, power beaming and operations in a form that is applicable to a real space elevator. This effort was ignored in the roadmap.
The roadmap discusses a tether experiment billed as demonstrating the ability to dodge satellites but it is at an orbit where they shouldn’t expect to collide with a satellite for hundreds or thousands of years unless they purposely place their system on a collision course with one. I would also be very surprised if Federal Aviation Administration, Department of Defense or the State Department allows Liftport to launch a tether to see is they can dodge active satellites. An alternative is to launch a second satellite and dance around it. However, the dodging techniques in any orbital system are completely different from those required for the anchored space elevator and thus of no value in a space elevator development program. The act of deploying is valuable but not the dodging as proposed here. The on orbit tether moving is a mission that Robert Hoyt (one of the advisors on this document) has proposed and would help develop his specific system.
The orbital environment test proposed was done on NASA’s Long Duration Exposure Facility spacecraft many years ago for most materials and testing of the carbon nanotubes would be best done at the numerous plasma labs around the country set up for this purpose. Due to the orbital velocity a satellite can not realistically test atomic oxygen degradation. Radiation tests would also be best done in a lab for a small fraction of the cost and for the better results that can be obtained on orbit. Other environmental tests have been done on other materials and doing them with carbon nanotubes will not provide additional information.
What is not on the roadmap is acquisition of financing, regulatory approvals for deployment and power beaming, ribbon design studies and testing, deployment spacecraft design, ribbon deployment studies, detailed laser and power beaming studies, system protection, system trade-off, system integration, etc. These are more critical than most of the items on the roadmap and they are not mentioned or listed.
Much of the schedule and development requirements have been done by people working on the space elevator and this roadmap would have benefited greatly from the information if Liftport would have decided to incorporate it. Unfortunately, with the faults and omissions of the Liftport roadmap there is no valuable material here. The schedule and suggested efforts are completely erroneous. To build a roadmap for the space elevator it would be much better to start with a clean slate that use this one as a template.
I would suggest that Liftport become part of the real effort to build the space elevator and work with members of the community instead simply trying to claim they are the effort.
