International Space Elevator Consortium
October 2015 Newsletter

In this Issue:

Editor’s Note
President’s Corner
Conference Mini-Workshop
Research Lab

Editor’s Note

Dear Friend,

Welcome to the October, 2015 edition of the ISEC eNewsletter.

This month's President's Corner talks about Make A Difference Day and the difference that ISEC volunteers are making and it ends with an apropos quote from Albert Einstein.

A report summarizing another one of the mini-workshops held at the recent ISEC Space Elevator Conference, this on the Marine Node, is also included. The workshop began with a talk from Vern Hall, discussing progress on the ISEC report on the Marine Node that he is chairing and then delved into construction issues, operational issues, etc.

Finally, this month's "Research Files" column discusses how to power the Tether Climber and gives a brief overview of the main options being considered at this point.

If you want to help us make a space elevator happen, JOIN ISEC and get involved! A space elevator would truly revolutionize life on earth and open up the solar system and beyond to all of us.

Please don’t forget to LIKE US on Facebook, FOLLOW US on Twitter, and enjoy the photos and videos that we’ve posted on Flickr and YouTube, all under our Social Identity of ISECdotORG.

Thank you! 
ISEC

President's Corner

Who Knew?  Make a Difference Day is the fourth Saturday of October, and has been for two decades.  The concept is simple:

"It is a day for non-profits, companies and individuals who want to make an impact to unite in common purpose - regardless of age, resources, income, environment or background - to change the world we live in for the better and accomplish extraordinary things."
[Arizona Republic, Oct 24th, 2015]

As the president of ISEC, I would like to say "our volunteers are making a difference!"  Thank you!  It seems to me that a non-profit, with many volunteers, can do almost anything.  It is amazing what a small group of history buffs can do when working together to "save our history."  It is amazing what a small group of volunteers can accomplish when the call is there to support the conference and its many complexities.  It is amazing what a small group of dedicated engineers, scientists, operators and professionals can accomplish when challenged to study a space elevator topic for a year.  I have always found it rewarding to ensure that each of our volunteers realizes that they are contributing to something bigger than just their tasks.  They are indeed helping the future of mankind move off planet and colonize the solar system.  They are ensuring that we will have inexpensive access to space for the benefit of humanity with almost free energy anywhere/anytime, nuclear waste disposal, high-speed communications anywhere at anytime (cheaply), and human exploration to the Moon and Mars.  Small contributions now, developing the concept of space elevators, will pay huge dividends to humanity in the future.  The path will be long and complex; but, the step-by-step methodology of volunteer support will ensure that our reach-out goals will be met.   Remember what Dr. Einstein said in June of 1905:

"Keep in mind that besides eight hours of work, each day also has eight hours for fooling around, and then there's also Sunday." Popular Science pg 56. Nov 2015.

Keep Climbing my Friends --  Pete Swan
        (pete.swan@isec.org)

Report from the 2015 Space Elevator Conference Mini-workshop on the Marine Node

A mini-workshop on the space elevator marine node was held at the August ISEC conference in Seattle.   The marine node is the interface between the space elevator and the Earth's surface where passengers and payload will be transferred from surface vessels or aircraft to tether climbers.  The workshop focused on four areas of study: the functional requirements of the marine node, its physical plant and operations, its organization and staffing, and the culminating demonstrations required to prove the feasibility of its key aspects.

The workshop commenced with a talk by Vernon Hall summarizing the progress of the Marine Node Study begun in the Fall of 2014.  The report includes discussions and conclusions concerning the need for a space elevator and what a typical day of space elevator operations would be like.  The marine node as currently envisioned consists of three floating platforms: a Primary Floating Operations Platform (PFOP) and two tether termini, all connected by a fleet of ocean-going vessels (OGV), helicopters and seaplanes.  The first 40 km of each tether is also included as part of the marine node.  The functional requirements include node location, methods of tether control and payload attachment, transport and service logistics, communications and security.  The PFOP is planned as new, purpose-built, construction, but early versions of it could rely on conversion of existing vessels or platforms.  The tether termini would likely be platforms very similar to offshore oil rigs or aircraft carriers.  The marine node will require a mix of existing and yet-to-be-developed technology which will have to be prototyped and demonstrated.

The marine node report will be supplemented by results from the workshop discussions which examined the tether terminus platforms, the PFOP and the culminating demonstrations.

The tether terminus is a complex interface between the mechanical aspects of the tether and the surface operations required to run and service it.  Each terminus must provide communications, power and tether control up to an altitude of 40 km. How the tether is attached to the platform will affect the methods of controlling its motion, which would include pulling on the tether or reeling it in and out.  The current plan sites the platforms on the equator to provide maximum payload capacity, but there are weather, tether control and debris avoidance advantages to siting them off the equator by as much as 8 degrees.  Efficient methods of payload assembly and transfer from platform to climber must be developed.  Regular maintenance of climbers, tethers and platforms must be planned; this entails a large, on-site store of spare parts as on-time delivery from the distant shore would be costly or unlikely. The platforms must be protected from their physical environment.  Although the platforms are massive and thus very stable under most conditions, floating breakwaters would mitigate wave action. Lightning protection for both platform and tether will be required and emergencies such as a tether break, sinking platform or hostile action should be anticipated.

The PFOP serves as the forward base of operations and seaborne port which will connect to the primary operations center (POC) and mainland cities.  It will coordinate inbound and outbound traffic and distribute it to the tether termini.  A land-based PFOP was discussed as having greater physical stability, lower construction costs and shorter supply lines, but these advantages must be balanced against safety, weather and national jurisdiction concerns. The PFOP will be the nexus for local communications and security operations as well as cargo handling and storage.  The staffing levels required to supply these functions are expected to be high, and difficult living conditions must be taken into account.  Robotics and teleoperation could reduce this level significantly.  The concerns of space elevator investors and the comfort of passengers must be taken into account early in the PFOP design stage.  On-site power generation will be necessary unless the PFOP is located near a shore.  A wide range of options was discussed, including custom-built nuclear plants, existing US Navy plants, harnessing wave action or ocean thermal energy, or tapping undersea oil or geothermal power.

Before being built or implemented, the feasibility of each key element of the space elevator must be demonstrated.  Several such culminating demonstrations were discussed, including the tether terminus concept, tether position management, the climber attachment/detachment procedures and power generation.   It must be shown that tether tension management is possible and that the relative position and tension of tether elements can be accurately monitored. Position management can be demonstrated using control and guidance systems which rely on physical registration markings on the tether.  The dynamic effect of attaching and detaching climbers to the tether must be demonstrated and the attachment/detachment procedure must show that several different types of climber can be accommodated.  Currently only payload and repair climbers are envisioned for standard operations, but others are likely.  A proof of concept for power generation for the terminus and the first 40 km of tether must show that power can be efficiently produced and distributed, taking into account surge protection, solar disruptions, and emergency power loss scenarios.

Once these challenges are met the marine node will become the spaceport of the future. It will grow from a small base into a busy commercial hub and eventually into a floating city with a large range of services and a sizable population.

The Research Lab

Various ideas have been considered for the best way to provide power to the tether climbers, including microwave power transmitted from Earth or alternating current sent through the tether itself. However, the two most likely contenders are solar power and laser power.

The main research questions for solar power are whether or when they will achieve the required power to mass ratio. There is rapid development in this field, but our requirements are still quite stringent by today's standards. We need to obtain 4 MW from a set of photovoltaic cells that are no more than about 2 metric tons in mass. This mass needs to include structural support strong enough to withstand full Earth gravity when it is near the Earth. This is in contrast to orbiting satellites that only open their solar panels in microgravity. The structure also needs to deal with the apparent movement of the sun during the day.

For laser power, progress is still needed in the optical technology to focus the beam from Earth onto the receiver on the tether climber. This needs to be done in such a way that it does not damage the climber. In addition, we need to assess the risk to satellites and spacecraft from a powerful laser beam, and this assessment should include the management system required to decide when to close and restart the lasers.

A third option is to use some kind of hybrid between solar power and transmitted laser power. For example, a laser could transmit power during the night if the solar panels can be directed towards it. A feasibility study on hybrid power is needed.