Editor's Note

Besides our regular articles that appear either monthly or semi-monthly, we have a couple of interesting articles that I would like to draw your attention to:

A young enthusiast named Ella has submitted a review of the Space Elevator Experience at Disney World. We hope you enjoy hearing about her experience!

ISEC is offering its first paid monthly internship! We are in need of someone to keep our website up to date and coordinate with various members of the ISEC community to ensure that articles are published to the website and archived in a timely manner. If this sounds like something you would like to do, read below!

Sandee Schaeffer
Newsletter Editor

President's Corner

by Pete Swan

New Terminology

Last month we had an article by ISEC board member, Adrian Nixon, on the new terminology for the future material of the Space Elevator. He started with simple concepts and then went deeper quickly (as least for a simple mechanical engineer). Adrian is doing a marvelous job of leading us into the world of 2D (two- dimensional) material science. I am trying to keep up, so, I thought I would revisit it from my perspective. Hopefully I “get it right.” Here goes…

In the last three years I have been segmenting graphene into three categories. That is not a sufficient differentiation for the listener or reader. They were:

  • Graphene powder: pencil lead and more recently the material added to concrete to enhance its performance in terms of strength, longevity, and cost saving; massive efforts in this field are going on around the world.

  • Polycrystalline graphene: remarkable material being produced today in wide sheets of single-atom layers with phenomenal strength; currently being developed for many manufacturing processes at kilometer lengths; however, it is not sufficiently strong for space elevator tethers

  • Single Crystal graphene: this revolutionary material has great promise for space elevator tethers; it has tensile strengths in excess of 100 GPa and is a continuous molecule potentially reaching 100,000 km long. (I know, I know—amazing!)

The problem is, these simple words do not reflect the massive improvements in material sciences and the potential benefits of each of the three types of graphene. As such, Adrian’s article last month [see the August 2022 issue of the ISEC newsletter] explained the aspects of van der Waals (vdW) homostructures, graphene layers, multiple layers, crystallinity, and large-area sheet graphene. After reading his article, I tended to jump to an answer and explain it in my head. I needed to try and speak the language of the graphene arena.

I have concluded that we (all space elevator enthusiasts) must start using his language to help foster understanding, illustrate progress in this science, and emphasize the importance of this remarkable progress occurring today (and in the near future). Please start using the following terms as you spread the word that the space elevator has a material that should be ready when our initial prototypes are scheduled (+/- 2032).

Graphene powder: Few and multi-layered graphene nanoplates as powder additives in other materials

Graphene Layers: Multi-layer polycrystalline graphene (loosely associated—not a VdW structure)

Graphene Laminate: Multi-layer polycrystalline graphene (layers held together in a VdW structure)

Graphene Super-Laminate (GSL): Highly coherent multi-layered sheets of molecules of single crystal graphene on a large scale.(layers held together in a VdW structure. In addition, this is an entirely new material not found in nature.)

Please try to use these terms when dealing with questions about tether material. The University of Manchester and other locations are currently working on Graphene Super-Laminate in laboratories and have active plans to break out into the manufacturing arena. We need to support Adrian in his quest to bring definition to this remarkable revolution in material science and the resulting phenomenal projects leveraging its strengths.

ISEC Intern Position—Website Support

The International Space Elevator Consortium (ISEC) is looking for someone with web page design experience to upgrade the ISEC website. This is a continuing internship with a stipend of $200 per month and is open to anyone with an interest in space elevators. The goals of this upgrade include:

  • Search engine optimization, increased hit rate, reduced bounce rate

  • Timely updating of content with exciting home page capturing visitors

The preferred candidate will:

  • Be familiar with SquareSpace

  • Be responsible for website upgrades and regular content updates

  • Have a good deal of latitude in design choices consistent with the above goals

  • Work with and be supported by the Office of the President

ISEC needs someone who will take ownership of the site, improve it with knowledgeable approaches for better presentation and then ask for content from the many ISEC players. Candidates are encouraged to look over the website (www.isec.org) to get an idea of the ISEC purpose, goals and content.

Apply at info@isec.org

OUR MISSION: The International Space Elevator Consortium promotes the development, construction and operation of a Space Elevator Infrastructure as a revolutionary and efficient way to space for all humanity. It will be the Green Road to Space. ISEC is made up of individuals and organizations from all around the world who share a vision of mankind in space.

Ella’s Trip on the Space Elevator

I’m Ella and I've been “up” the space elevator.

I’m 16 and I’m from Halifax, West Yorkshire. I like books, mythology, cats, and all things Disney, and I have an unhealthy obsession with the Marauders (it’s a Harry Potter thing).

I have also recently started being interested in space and the James Webb telescope, mainly because space looks cool.

My mum works with Adrian Nixon and talks about graphene and the space elevator a lot, which was interesting…until it wasn't.

We went to Disney World this July for my birthday. I loved the Disney trip; I love rollercoasters and Disney. My favorite rides were Tower of Terror, Rock ‘n Rollercoaster, and Splash Mountain. I also got to meet Mickey on my birthday.

Late on our last day in Epcot we were in World Discovery and we had just come off Mission Space. I wanted to go on the Test Track because we hadn’t been on it yet, but mum decided to check if there were any cancellations for the space elevator. She had tried to book but it was full. There were 2 spaces at the bar. So, we went…yay.

But despite not wanting to be there and the elevator not actually moving (have you ever heard of an elevator that doesn't move? No. Neither had I) it was good.

The “elevator” had screens above and below and did look like it was moving away from the earth and towards the docking station. There was also a space window in the restaurant. We sat at the bar, and I got a coffee mocktail called the Milky Way that had a tiny Milky Way chocolate attached to it and it tasted great. I did also get to go on Test Track afterwards, which was great.

ISEC’s Outreach at the International Astronautical Congress

Paris 2022

As you can imagine, going to a technical conference with over 6,000 experts attending can be quite daunting. Who can you talk to? Will they listen to me? What are the current “hot topics”? When will I see my friends? How do I keep up with the frenetic pace of these remarkable multiple symposia? And, then of course, when do I sleep? All these questions pop up each time I attend one of the IACs around the world.

The visibility into the global space community is remarkable and rapidly influencing the world’s look—both outward and inward. However, one of the comforting factors for me is that the Space Elevator Community is gradually influencing the space community, moving forward in our presentations and reaching many of those we need to “touch.” It is difficult to plan and execute activities inside such a diverse set of events, all going in parallel.  Remarkably, we at (ISEC) tend to achieve just that each year with a series of presentations, focused efforts in specific parallel areas, and multiple smiles as we wander between talks trying to capture people and concepts at the same time. This year our team will have a remarkable series of presentations that will spread across the space elevator development arena. It is not only ISEC, but contributors from our global team who believe we should be moving forward and contributing towards such mission successes in the future. The list below shows the contributions of ISEC participation. As you know, the title does not tell the whole story, but it starts the discussions. Here are the ISEC speakers and their topics:

IAC-Topics

There are several other great papers to be presented from around the world. Japan leads with three talks; India (2) and the UAE (1) also contributing. The UK has four of ours.

Reminder: Next May, Dallas hosts the International Space Development Conference and Baku hosts the IAC in October. See "Upcoming Events" below.

Tether Materials

by Adrian Nixon, Board Member, ISEC

Thinking About How to Prevent Slipping
in a Layered Tether

In the previous newsletter entry, we introduced the term “Graphene Super-Laminate” (GSL) as the language to use that would describe multiple layers of single crystal graphene, such as that used to make the tether for the space elevator.

We are acquiring more knowledge about GSL as we study its mechanical properties. One aspect we have been studying is how strongly the layers are held together. We know an individual layer of single crystal graphene has covalent bonds that confer an incredibly strong tensile strength (130 GPa) [1].

We also know that the graphene layers in GSL are naturally held together by van der Waals (vdW) bonding and this is much weaker than the covalent bonds. Understanding the strength of the vdW bonding in GSL is important to us. Consider a climber that ascends the tether using opposing wheel pairs with the tether pinched between the wheels. If the van der Waals forces are not strong enough, large shear forces on the tether material will not be sufficiently distributed into the bulk and de-lamination could occur.

We need to understand how the tether will behave under loading as the layers may slip and slide over one another. For this we need to know the shear modulus of GSL. As a result of work done by the climber-tether interface study group we have discovered that the shear modulus of GSL is between 0.19 to 0.49 GPa [2], about 35 times too weak to support a 20-t climber. Thus, another bonding option must be considered.

In GSL, the carbon atoms are connected by hybrid sp2 bonds. The remaining pi (π) orbitals are unbonded and oriented perpendicular to the plane of the graphene layer. When two such layers are pressed together with sufficient force, the sp2 bonds and π orbitals create sp3 bonds between the layers, as shown in fig 1.

Fig.1: Stick-and-ball model of “spot-welded” multilayer graphene.

The sp3 hybrid bonds are shown in the center, between two layers of graphene

The sp3 hybrid bond is the one found in diamond and accounts for its strength. The pressure at which this type of bonding occurs is thought to be about 20 GPa [3]. It has been shown recently that when large numbers of atoms take part in this bonding, the results are irreversible [4]. Perhaps this process could be applied on an industrial scale to produce a material resistant to the shear stresses expected in the space elevator tether.

What all this means is that we may find that layers in a graphene tether may slip and slide over one another as the climber grips the material and pulls itself up and down. We have found a solution in the literature that could give us a mitigation for this problem. This involves creating cross-links between the layers. In effect we can "spot weld" the tether and improve its resistance to slipping under shear.

References:

1. Lee, C., Wei, X., Kysar, J. and Hone, J., 2008. Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene. Science, 321(5887), pp.385-388.

2. Qu, W., Bagchi, S., Chen, X., Chew, H. and Ke, C., 2019. Bending and interlayer shear moduli of ultrathin boron nitride nanosheet. Journal of Physics D: Applied Physics, 52(46), p.465301.

3. Yoshiasa, A., Murai, Y., Ohtaka, O. and Katsura, T., 2003. Detailed Structures of Hexagonal Diamond (lonsdaleite) and Wurtzite-type BN. Japanese Journal of Applied Physics, 42(Part 1, No. 4A), pp.1694-1704.

4. Niu, C., Zhang, J., Zhang, H., Zhao, J., Xia, W., Zeng, Z. and Wang, X., 2022. Configuration stability and electronic properties of diamane with boron and nitrogen dopants. Physical Review B, 105(17).

History Corner

by David Raitt, ISEC Chief Historian

Editor's Note: This is part one of a two-part article. See the next issue for part two.

Space Elevator Architectures
Part 1

As we know, the idea of a space elevator has actually been around for some 125 years. Since that time there have been various insights gained from the published descriptions concerning its concept and different elements, including its construction, engineering details, criteria, development, function, purpose, and operation. All these diverse insights have led to refinements and modifications of the various components making up the entire system—its architecture. This month’s History Corner gives a very brief overview of these diverse space elevator architectures (now eight in number) made over the years to date. A more comprehensive account by David Raitt on Space Elevator Architectures can be read in Quest: The History of Spaceflight Quarterly, v28, n1, 2021, p17-26.

The First Architecture

Konstantin E. Tsiolkovsky, one of the fathers of rocketry, wrote a collection of essays in 1895 called “Dreams of Earth and Sky” in which there is what is generally considered to be the earliest abstract imagining of a space elevator. Interested in gravity, Tsiolkovsky tried to calculate the centripetal force that would be required for one to be free of Earth’s gravitational influence entirely. Inspired by the Eiffel Tower, Tsiolkovsky imagined larger towers situated at the equator that stretched up into the heavens, at the top of which sat what he called “celestial castles.” With Earth’s gravity seeming to vanish entirely at a distance he measured of roughly 36,000km (or geostationary orbit), combined with the effects of the centripetal force provided by the rotation of the planet, he suggested that anyone standing inside his celestial castle would be looking up at the Earth, instead of down, as the pull of gravity would be effectively flipped. Furthermore, his towers would be able to launch objects into orbit without employing rockets. Although this sounds like the basis of a space elevator, Tsiolkovsky never took his ideas much further.

The Second Architecture

Sixty-five years later, Yuri N. Artsutanov, developed a more feasible scheme for building a space tower by using a geosynchronous satellite as the base from which to construct it. Using a counterweight, a cable, constructed of some advanced super-material would be lowered from geosynchronous orbit to the surface of the Earth while the counterweight was extended from the satellite away from Earth, keeping the centre of gravity of the cable motionless relative to Earth. Artsutanov’s ideas were published in an article entitled “To the Cosmos by Electric Train” in the Russian tabloid Komsomolskaya Pravda on 31 July 1960.

In this early depiction of what could be considered a space elevator, Artsutanov believed rockets were too dangerous, had too lengthy a preparation time prior to launch, and thus were an inefficient means of getting off the Earth. His notion of celestial moorings, or orbital spaceports, would allow for the docking and embarkation of large interplanetary vessels. These way stations would also employ smaller shuttles to ferry people to and from the planetary bodies they orbited. Artsutanov’s concept envisioned that instead of using rockets to transport people up from the ground, travelers would use railways that would extend into the sky, tying the ground terminals on the surface directly to their orbital counterparts above.

Artsutanov’s elaborate engineering approach was sufficient to later label him as one of two independent co-inventors of the space elevator. The other was Jerome Pearson working independently fifteen years later.

The Third Architecture

In 1975, Jerome Pearson, finally managed to have published his article “The Orbital Tower: A Spacecraft Launcher Using the Earth’s Rotational Energy.” It was a definitive paper that announced the entry of the space elevator to the scientific community at large (because it was in English) and was a major step forward to bringing it to reality. Pearson resolved many issues with engineering calculations of tether strengths needed and approaches for deployment. His article was the first mathematical presentation of the space elevator and convinced scientists and engineers that such a grandiose alternative to rocketry was not only theoretically possible, but also the right way to go. Pearson’s work, in fact, made a leap beyond Artsutanov’s and set the stage for the modern design for space elevators. He asked his readers to imagine a physical connection being made between a satellite at geostationary orbit and the Earth’s surface below. He suggested that through the use of this connection, the deployment and return of satellites and spacecraft to and from the planet would be much safer and require far less energy, which as a consequence, would also make them cheaper.

Whereas Artsutanov imagined his counterweight attached at a distance of 60,000km, where it would double as a spaceport, Pearson fastened his at the much further distance of 144,000km. Pearson’s design did not call for a true counterweight per se as he believed the sheer distance and mass of the line, and the outward force placed upon it by the spinning planet, would be sufficient to keep the structure standing.

Pearson saw the elevator directly employing the inertia generated by the centrifugal movement of the rotating system to slingshot craft away from the planet. He estimated that anything launched in this manner from appropriate distances above the geostationary point would be able to reach as far out as Saturn without using any form of rocketry. This meant that traveling to Mars, for instance, would require no more energy than what was needed to reach geostationary orbit.

Pearson backed up his explanations of a space elevator with countless numerical calculations. He thoroughly accounted for every technical aspect of his elevator’s design and operation, including the sources of energy, the material of the line or tether its minimum strength-to-weight ratio, and the need for it to be tapered.

Editor's Note: See next month's issue for Architectures four through eight.

Upcoming Events

73rd International Astronautical Congress

Sponsored by the International Astronautical Federation (IAF)
https://www.iafastro.org/events/iac/iac-2022/
Sunday, September 18th through Thursday, September 22nd, 2022
Paris, France

The Space Elevator session takes place Monday, September 19th from 3:00 PM until 5:30 PM local time. It will be Session 3 “Modern Day Space Elevators Entering Development” of the 20th IAA Symposium on Visions and Strategies for the Future.

World Space Week

Sponsored by the British Interplanetary Society
https://www.worldspaceweek.org/
Tuesday, October 4th through Saturday, October 10th, 2022
This year’s theme is “Space and Sustainability.”

World Space Week consists of space education and outreach events held by space agencies, aerospace companies, schools, STEM clubs, science centres, planetaria, museums, and astronomy clubs around the world. World Space Week events also include ANY SPACE-RELATED activities being held by local communities, groups, home-schooling, and even families, between 4-10 October.

International Space Development Conference

Sponsored by the National Space Society
https://isdc2023.nss.org/
May 25th through May 28th, 2023
Dallas-Frisco, Texas, USA
Theme: A New Space Age

74th International Astronautical Congress

Sponsored by the International Astronautical Federation (IAF)
https://www.iafastro.org/events/iac/iac-2023/
Monday, October 2nd through Friday, October 6th, 2023
Baku, Azerbaijan

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