The preliminary meeting of the ISEC Marine Node team was conducted as a mini-workshop at the 2014 Space Elevator Conference in Seattle.  We had a fantastic discussion on the development of the Marine Node, identifying and exploring multiple topics that are essential for making progress on this key element of a space elevator system.

Marine Node Overview

Dr. Peter Swan, acting as workshop leader, presented the following graphic for the Space Elevator Marine Node.


The image shows two Marine Nodes, each consisting of a single Floating Operations Platform. The platform in the foreground is shown with a support vessel alongside. The Marine Node may also include an additional Facilities Support Platform. Another key element, the port facilities to support the node, is not shown.

Workshop participants discussed five parameters of proposed locations: ocean currents, sea water status and makeup, sea floor geology and seismology, and weather conditions.  Obviously, these are just some of the parameters of interest.  Attendees also participated in a brainstorming process to develop new concepts and ideas for the Marine Node.

Workshop Goals and Processes

The goal of the mini-workshop was to develop a description of the Marine Node and show how to move towards operations, driving innovations in node design and lowering development risk.

    1. Define the Problem.  The questions presented to the workshop participants included these:
      • Where should the Marine Node be located?
      • How many platforms should be provided for each node?
      • What are the characteristics and requirements of the tether connection?
      • What resources are required to meet the throughput goals of the node?
      • What are the security concerns for the node?
      • What businesses can operate at the node?
    2. Build on the Marine Node baseline.  Over the last few years, there have been multiple solutions proposed to the problem of how to develop a space elevator Earth anchor, including these:
      • Dr. Edwards’ baseline: Single tether, middle of Pacific, oil rig, laser powered
      • IAA baseline: Multiple sites with paired tethers and solar-powered climbers
      • Keith Henson’s proposal: Marine nodes 8° south of the equator, angled tethers
      • Japanese proposal: Floating tunnel to island-based surface node, 100 MT tethers
The team looked at these proposals and considered the positive and negative aspects of each to enable progress forward.
  1. Make specific proposals.  The following discussion notes are the product that the team developed in the mini-workshop. They comprise three elements:
    • Definition of functional needs to be fulfilled by Marine Node.
    • Presentation of multiple solutions to the needs.
    • Description of the “best” solutions available today or in the future.  This set of descriptions should enable future designers to leverage our comparisons and understand our engineering trades.

Discussion notes

From the teams at separate tables, discussions developed observations, ideas, proposals, and preliminary conclusions in several areas:

  1. Loading due to tether
    1. The tether anchor must counteract an upward force of less than 500 tons.
    2. High Stage One provides 25,000 tons of down-force.
    3. For the case of an off-equator tether (4 to 8 degrees south) the tether will be roughly 20 degrees from vertical, leading to significant transverse forces of about 100 tons.
    4. Fuel for marine thrusters required for station keeping at surface node, but not for high stage one
  2. The logistics stream from tether base to main base of operations
    1. The team considered ports in Hawaii, South America and Panama
    2. Distance from port:
      1. Locating the platforms 200 miles from a major port is considered practical
      2. A position 1,000 km west of Galapagos would be more difficult to support
    3. Food, fuel are significant components of the consumables requirements
    4. several tugs will be needed
    5. Docking facilities will be required at the platforms
  3. Emergency/medical response
    1. For the more distant platform locations, for example 1,000 km west of the Galapagos, only a few helicopters exist with sufficient range to reach major medical facilities.
      1. E.g., the AH-56A, Mi-26, V-22, etc.
    2. Should we rely on Navy carrier groups for medical and evacuation?
    3. Sufficient on-site medical could be developed – it is scalable from existing offshore operations.
  4. Moving the platform in case of storm, orbital debris, etc.
    1. It may be necessary to move the tether platform as much as 50 miles.
    2. A 100-ton tug would be sufficient to provide the necessary movement.
    3. How quickly could the base be moved?  Assuming base is moored to sea floor, a few hours to drop moorings and get underway. A 100-ton tug could move the platform at a speed of 2-3 knots.  With integrated submarine propulsion, a speed of 10 knots may be possible.
    4. Movement available at top of High Stage One is 20 – 30 km.
    5. An off-equator platform could be moved by reeling the tether in or out.
  5. Seismic loading from sea floor.
    1. There is little seismic activity at nominal location and sea floor depth of 8,000 ft.
  6. Additional features and functions
    1. Tether terminus
    2. Tether/FOP Dynamics
    3. Likely new OGVs (Cruise Ships?)
    4. Greater storage capacity (climbers and payloads)
    5. Larger numbers of operations and support personnel
    6. Keep-out zone (safety and security)
    7. Greater movement capability, possibly faster
    8. Larger operations center
    9. More in-depth weather (and ocean) monitoring/sensing
    10. Climber mating equipment
    11. Greater power generation (4 MW for climber)
    12. Power cord handling equipment
    13. Climber refurb facilities
    14. 16 MT per day throughput
    15. 48 MT storage – preparation
    16. 48 MT storage – waiting movement
    17. Climber Repair Modules – storage and preparation
    18. Communications Node

Summary Statement

The mini-workshop defined and discussed many potential problems and solutions for the space elevator Marine Node.  The conference attendees became actively involved in the discussions and ideas flowed freely, achieving progress in the conceptual development of the Marine Node.