Elevator from the Moon, Ion Engines in Space and Automated Mooring
November 21
This week we investigate a new proposal for a space elevator, this time one tethered to the moon. We examine a set of design goals for an Ion Engine that will be able to take us to nearby celestial bodies far more quickly than current technology. We find out about an added benefit from going to the gym and finally we discover a new automated mooring system that is designed for use on automated boats.
Elevator from the Moon
There have been many proposals for building a space elevator to help reduce the cost of rocket launches. If we could build an elevator to space this cost could be reduced substantially. The problem with most of these proposals is that they require materials that we have not yet discovered or invented. The immense tension of a cable that extends from earth to beyond geostationary orbit is beyond today’s materials.
A team from the University of Cambridge and Columbia University have proposed a groundbreaking solution that makes use of current materials. Instead of anchoring the cable on earth the team proposes anchoring the cable on the moon and extending it towards earth. This takes advantage of the moon’s slower orbital rotation and the gravitational equilibrium between the two bodies.
At the Lagrange Point between the Earth and the Moon the gravitation pull of each body cancels the other out. Below the Lagrange Point Earth’s gravity would pull the cable downward. Above it the Moon’s gravity takes over. This setup reduces the tension on the cable making current materials viable. A cable as thick as the lead in a pencil could be constructed for several billion dollars, a similar cost to most other space projects.
The cost saving comes from not having to use a rocket to get to the moon, the spacecraft would pull itself along the cable once it has reached the Lagrange point. There is also no need to decelerate when the spacecraft arrives at the moon. The team estimates that the fuel required for a trip to the moon will drop to about 1/3 of the current cost.
The Lagrange Point offers a stable platform for construction of the cable. Materials will remain near the construction craft for some time without drifting away. This project may make frequent travel between the Earth and the Moon a reality. Costs would plummet and larger payloads could be more easily transported.
Ion Engines in Space
Whilst we are taking about space exploration, a team from the Initiative for Interstellar Studies from the UK, has proposed a new electric propulsion system known as an Ion Drive to power spaceships. They estimate that we could reach the solar gravitational lens (a point in space 550AU or Astronomical Units away from Earth. 1AU = the distance from Earth to the Sun) in less than 13 years.
The team proposed a power plant that can output 1 Kilowatt per kilogram of weight. Current Ion thruster power sources produce about 10 watts per kg. Current nuclear technology produces about 100 watts per kg. We have work to do however we now know what is required.
Another consideration is thrust efficiency. The ideal is 97% efficiency compared to the 75% to 80% currently available. The third important characteristic is specific impulse (the change in momentum per unit mass of propellant in a propulsion system). Improvements in specific impulse is being held back due to the inability to produce power plants that can support the levels of specific impulse required. Solving the power plant issue will allow the required development.
If we solve all these issues the team calculates that a payload of 18,000 kilos could reach the solar gravitational lens in less than 13 years. This is vastly faster than any other mission to date.
How the Nervous System benefits from you going to the Gym
Regular exercise is good for the body in many ways. It strengthens muscles, bones and the immune system. A team from MIT have now found that it also benefits the individual neurons in our muscles.
The team discovered that when muscles contract they release a series of biochemical signals called myokines. The team observed that neurons grew four times longer when exposed to myokines compared to neurons with no exposure. Additionally the neurons responded positively to the physical impacts of exercise. When repeatedly puled back and forth the neurons grew just as much as when exposed to myokines.
This muscle-nerve cross talk may be useful for treating nerve injuries. For example when the communication between a muscle and a nerve is cut off. Stimulating the muscle may encourage the nerve to heal. Hopefully this might help to restore movement in those with traumatic injuries.
The team sees their work as the first step toward understanding and controlling exercise as medicine. In the mean time, keep going to the gym. It is good for you in many ways, including some that we don’t know about yet.
Autonomous Ship Docking
A team at the Korea Institute of Machinery and Materials have developed an automated mooring system for autonomous vessels. Currently vessels of all types are secured using thick mooring lines. These lines require high tensile strength which varies depending upon the ship’s size and weight.
The new system uses a combination of suction pads and a flexible hydraulic mechanism. Safe mooring is enabled through the control of a vacuum suction pad and a 4 degree of freedom hydraulic mechanism. The suction system secures attachment and the hydraulic system maintains control.
This new technology streamlines the mooring process increasing both speed and accuracy whilst reducing accidents and labor needs. The team hope to have the system verified at sea in 2025 before commercial availability soon thereafter.
Paying it Forward
If you have a start-up or know of a start-up that has a product ready for market please let me know. I would be happy to have a look and feature the startup in this newsletter. Also if any startups need introductions please get in touch and I will help where I can.
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Till next week.