President’s Note

by Dennis Wright

Space Elevators at the Art Museum

Three ISEC members, John Knapman, Adrian Nixon, and Pete Swan recently participated in a multi-disciplinary program sponsored by the National Museum of Modern and Contemporary Art in Korea.

The program was a unique blend of science, technology, art, and human experience surrounding the space elevator. Pete spoke about the great potential of space elevators, Adrian about the strong materials required, and John about the latest space elevator research. There was also a dialogue among representatives from the art, technology, and human factors communities.

While John, Adrian and Pete presented virtually, this was an in-person event at the museum and was attended by prominent Koreans involved in various aspects of space elevators. As a result of this program, ISEC has made contact with several researchers at KIST (Korea Institute of Science and Technology) working on strong materials, the key to building a space elevator. We hope this will be the beginning of a fruitful collaboration.

Critical Research Projects

As regular readers of this newsletter know, the development of strong materials is essential for the building of the space elevator. Progress in this area has been rapid during the last decade, but still, many challenges remain. If you add research in tether dynamics, the “climbability condition” (the set of physical conditions that must be achieved for tether climbing to be possible), atmospheric effects on the tether, and debris avoidance, you create a “top five” list of ISEC research projects.

In coming newsletters, I’ll be concentrating on each of these projects and pointing out areas in which volunteers can make real contributions. You’ll start to see details on this at the ISEC webpage (www.isec.org). If you can’t wait for the next newsletter or are simply interested or want to become involved, contact me at dennis.wright@isec.org.

Dennis Wright

Chief Architect’s Corner

by Peter Swan, Ph.D. FBIS, FAIAA, MIAA

Architectural Note #52
Definition of the Modern-Day Space Elevator 

“Modern-day space elevators have emerged over the last four years within the International Space Elevator Consortium (ISEC) community after growing through eight distinct system architecturesi and they have remarkable strengths.”ii This basic premise (and title) has developed through 19 research studies conducted by the International Academy of Astronautics, the Obayashi Corporation, and International Space Elevator Consortium. The results have shown that:

+ Space Elevators are feasible with a defined road to the space elevator eraiii

+ These roads to space are environmentally neutral – Green Roads to Spaceiv

+ They are ready to enter the engineering verification (testing) stage in development.v

+ The 100,000 km tether could be in production within 10 years.vi

+ Modern-day space elevators will enable transformative capabilities.vii

+ It is estimated that after Initial Operational Capability (IOC) is reached, the capacity is 30,000 tonnes per year [Humanity lifted only 22,000 tonnes between 1957 and 2020].viii

+ Will join Advanced Rockets in a Dual Space Access Strategy leveraging the strengths of both rockets and space elevators leading to a remarkable combination of strengths.ix

With these revolutionary capabilities, expanded in the next few paragraphs, modern-day space elevators will be permanent space access infrastructures for daily, routine, safe, inexpensive, and environmentally neutral operations that are also efficient in logistics delivery.

Figure 1: Modern-Day Space Elevator

What is a Modern-Day Space Elevator? Space Elevators are permanent transportation infrastructures which are ecological and "beat the gravity well". Their overriding strengths are efficiency in supplying massive amounts of cargo to GEO and beyond while being environmentally neutral. The concept is simple; attach a heavy Apex Anchor to the top end of a tether and it will rotate with the Earth. This is just like taking a rock on a string and swinging it around. The force outward keeps it stable while your string keeps it from escaping. Then you build tether climbers to raise themselves up the one-meter-wide tether until they get to their destinations on the tether or reach their release points to be thrown towards their mission locations.

The current concept is to place two Space Elevators inside a commercial venture operating as a Galactic Harbour with one-up/one-down operations including a natural backup capability. In addition, this plan is to have three Galactic Harbours spread around the equator as shown in Figure 2. Space Elevators have the following segments:

+ Earth Port and Earth Port Region: A complex located at the Earth terminus of the tether on the ocean.

+ GEO Region: The complex of Space Elevator activities positioned in GEO

+ Apex Anchor and Region: A complex of activity is located at the upper end of Space Elevators providing counterweight stability and full-service transportation nodes (“truck stops”).

+ Tether Climbers: Vehicles able to climb or lower themselves on the tether

+ Tether: 100,000 km long woven ribbon with sufficient strength and length. Recently, ISEC research led to: “The manufacture of tether-quality material for a Space Elevator still needs more development, but the trajectory to a high-quality industrial product is clear. It is not unreasonable to think that, as this graphene process continues apace, Space Elevator tether production could begin in five to ten years using graphene as its material.”x

Figure 2: Distribution of Three Galactic Harbours

Understanding Transformational Characteristics: The transformation of space access created by space elevators’ permanent infrastructure operations will be similar to moving from small boats crossing a large river to a permanent infrastructure such as a bridge moving traffic daily, routinely, safely, inexpensively, and with little environmental impact. From a historical transportation perspective, canals, channels, and deep-water ports are infrastructure; the ships are vehicles. Likewise, highways, bridges, and transcontinental rail systems are infrastructure for ground transportation. In the Modern-Day Space Elevator proposal, climbers are the vehicles while the reliable, permanent space infrastructures include tethers, Earth Ports with several termini and operational platforms, GEO Node structures including repair garages and stations, and Apex Anchors. Permanent transportation infrastructures exhibit these strengths:

+ Daily, routine, safe, and inexpensive -- with unmatched efficiencies

+ Inherently has the economic strengths of strategic investment, ubiquitous access, and uninterrupted exchange of resources

+ Massive movement [Initial Operational Capability (IOC) at 30,000 tonnes/yr with Full Operational Capability (FOC) 170,000 tonnes/yr]xi

+ High velocity [starting at 7.76 km/sec at 100,000km altitude enables rapid transits to the Moon (14 hours), Mars (as short as 61 days with daily releases) and beyond]

+ Insures environmentally neutral operations as a Green Road to Space

+ Eliminates rocket fairing design limitations

+ Assembly/storage at the top of the gravity well

Understand that Modern-Day Space Elevators are “Massive Green Machines”: Recently, ISEC completed an 18-month studyxii that evaluated Space Elevators’ environmental factors. This study started critical discussions by showing the additional benefits of Space Elevators being defined as "Massive Green Machines." They do not burn rocket fuel in the atmosphere or leave debris in orbit. They enable environmentally enhancing missions that require massive movement to GEO and beyond. In point of fact, the operations of Space Elevators and Galactic Harbours will be carbon negative. Several of the concepts developed during this study establish the reality that Space Elevators can make the Earth Greener. This net assessment trade study conducted by ISEC showed that: “Space Elevators and Galactic Harbours are Big Green Machines designed to improve the Earth's environment through two significant contributions. The first is the remarkable "zero-emission" lift of cargo to space, reducing environmental impacts from rocket launches. The second is the ability to deploy massive systems to GEO and beyond which minimize rocket launches by becoming a partner in a Dual Space Access Architecture.”xiii

Chart 1: Comparison

Internalize Unmatched Efficiency for logistics delivery to GEO & Beyondxiv: Chart 1 shows the mass delivered to GEO & Beyond to reflect movement by Space Elevators. This estimate is developed to illustrate efficiencies of advanced rockets becoming operational within the next few years while comparing estimates for Modern-Day Space Elevators. In addition, the next chart reflects growth from Initial Operational Capability (30,000 tonnes per year) to Full Operational Capability (170,000 tonnes per year). This growth was researched and detailed during the ISEC study with Arizona State University and published in Chapter 5 of the Research Study Report.xv

This capability of Space Elevators dwarfs advanced rockets rapidly because of their unmatched efficiencies of delivery and environmentally friendly operations. Indeed, Space Elevators answer the conundrum of rockets by delivering 70% of its liftoff mass to GEO and beyond. The conundrum of rockets is the simple realization that the delivery of mass to its destination is an insignificant percentage of the mass on the launch pad. The glaring example is the delivery of half percent of the launch pad mass to the surface of the Moon for Apollo 11. As shown in Chart 1, it is up to 2% for delivery to GEO and woefully small for delivery to Mars’ orbit. The question is why would you employ a methodology for delivery that only delivers less than one percent to your desired location (let’s say a future Gateway around the Moon). Modern-Day Space Elevators solve that conundrum by delivering 70% of mass at liftoff (the other 30% is the tether climber and will be reused repeatedly) to GEO and beyond by leveraging electricity.

Chart 2: Tonnes/yr to GEO and Beyondxvi

Schedule: The estimated layout for growth Modern-Day Space Elevators is:

+ 2025-26 Creation of initial testing organization

+ 2026-30 Finalization of validation testing and move to prototyping

+ 2030-33 Prototype testing and beginning of production

+ 2033-37 Launching, orbiting, deploying, and building up initial space elevator

+ 2037-42 Growth of Space Elevators to IOC

+ 2042-45 Expanding to FOC

+ 2045 Fully operational with 173,010 tonnes to GEO and beyond

+ 2046+ Expansion to new Galactic Harbors

Summary: The previous discussions have laid out an approach for understanding the term “Modern-Day” when applied to Space Elevators. In addition, these revolutionary characteristics represent a transformational space access system that is indeed a permanent infrastructure. The architecture should grow into a cooperative and competitive arrangement with advanced rockets.xvii The concept has matured into the Modern-Day Space Elevator and is ready to start development. As such, it answers the question WHY?

Why Modern-Day Space Elevators?

Unmatched efficiencies for moving transformational amounts of mass to space on a permanent space transportation system (70% vs. 2% to GEO and the Moon) while being environmentally neutral.

References 

i Raitt, D. “Space Elevator Architectures,” Quest, Vol. 28, #1, 2021 pg. 17-26. https://www.isec.org/s/space-elevator-architectures-2021-raitt.pdf

ii Swan, C. “Modern Day Space Elevator,” SpaceFlight, Vol 65 #6, June 2023. https://www.isec.org/s/spaceflight-june-2023-4-modern-day-space-elevators.pdf

iii Swan, P., D. Raitt, C. Swan, R. Penny, J. Knapman. International Academy of Astronautics Study Report, Space Elevators: An Assessment of the Technological Feasibility and the Way Forward, Virginia Edition Publishing Company, Science Deck (2013) and: Swan, P., D. Raitt, J. Knapman, A. Tsuchida, M. Fitzgerald, Y. Ishikawa, Road to the Space Elevator Era, Virginia Edition Publishing Company, Science Deck (2019)

iv Eddy, et.al., "Space Elevators: the Green Road to Space," ISEC Report, Lulu Publishers, April 2021. https://www.isec.org/studies/#GreenRoad

v Swan, P., D. Raitt, C. Swan, R. Penny, J. Knapman. International Academy of Astronautics Study Report, Space Elevators: An Assessment of the Technological Feasibility and the Way Forward, Virginia Edition Publishing Company, Science Deck (2013) and: Swan, P., D. Raitt, J. Knapman, A. Tsuchida, M. Fitzgerald, Y. Ishikawa, Road to the Space Elevator Era, Virginia Edition Publishing Company, Science Deck (2019)

vi Nixon, Adrian, John Knapman, Dennis Wright, “The Right Stuff,” Spaceflight, Vol. 65, No 6, June 2023. https://www.isec.org/s/spaceflight-june-2023-1-the-right-stuff.pdf

vii Swan, C. “Modern Day Space Elevator,” SpaceFlight, Vol 65 #6, June 2023. https://www.isec.org/s/spaceflight-june-2023-4-modern-day-space-elevators.pdf

viii Swan, P, Swan C, Fitzgerald, M., Peet, M, Torla, J, Hall, V., "Space Elevators are the Transportation Story of the 21st Century," ISEC Study Report, 2020. https://www.isec.org/studies/#TransportStory

ix Eddy, J., P. Swan, C. Swan, P. Phister, EN Scott, R. Centers, S. Gosavi, A. Baraskar, B. Sabra, “Leverage Dual Space Access Architecture, Advanced Rockets and Space Elevators,” ISEC Report, Lulu Publishers, April 2023. https://www.isec.org/studies/#LeverageDualSpace

x Nixon, Adrian, John Knapman, Dennis Wright, “The Right Stuff,” Spaceflight, Vol. 65, No 6, June 2023. https://www.isec.org/s/spaceflight-june-2023-1-the-right-stuff.pdf

xi Swan, P, Swan C, Fitzgerald, M., Peet, M, Torla, J, Hall, V., "Space Elevators are the Transportation Story of the 21st Century," ISEC Study Report, www.lulu.com, 2020. https://www.isec.org/studies/#TransportStory

xii Eddy, et.al., "Space Elevators are the Green Road to Space," ISEC Report, Lulu Publishers, April 2021. https://www.isec.org/studies/#GreenRoad 

xiii Eddy, J., P. Swan, C. Swan, P. Phister, EN Scott, R. Centers, S. Gosavi, A. Baraskar, B. Sabra, “Leverage Dual Space Access Architecture, Advanced Rockets and Space Elevators,” ISEC Report, Lulu Publishers, April 2023. https://www.isec.org/studies/#LeverageDualSpace

xiv Calculations conducted inside the ISEC Research Study “Dual Space Access Architecture” published 2021. Download, free pdf at www.isec.org

xv Swan, P, Swan C, Fitzgerald, M., Peet, M, Torla, J, Hall, V., "Space Elevators are the Transportation Story of the 21st Century," ISEC Study Report, www.lulu.com, 2020. https://www.isec.org/studies/#TransportStory

xvi Swan, P, Swan C, Fitzgerald, M., Peet, M, Torla, J, Hall, V., "Space Elevators are the Transportation Story of the 21st Century," ISEC Study Report, www.lulu.com, 2020. [Chapter 5] https://www.isec.org/studies/#TransportStory

xvii Eddy, J., P. Swan, C. Swan, P. Phister, EN Scott, R. Centers, S. Gosavi, A. Baraskar, B. Sabra, “Leverage Dual Space Access Architecture, Advanced Rockets and Space Elevators,” ISEC Report, Lulu Publishers, April 2023. https://www.isec.org/studies/#LeverageDualSpace

Pete Swan Visits the AMRC in November 2024

Our Chief Architect and past President of ISEC, Dr. Pete Swan, just returned to the United States after visiting the UK in November. As part of his tour, he visited the University of Sheffield, Advanced Manufacturing Research Centre (AMRC), a world leader in manufacturing excellence. The AMRC works closely with significant industrial partners such as McLaren, Rolls Royce, and Boeing who are co-located on the Sheffield site.

Advanced Manufacturing Research Centre (AMRC) Factory 2050. Image credit: University of Sheffield.

Pete had been invited by Prof. Mike Maddock and Space Hub Yorkshire to talk about his career and his work with the space elevator. The event is called Horizons Beyond: Fireside Chats on the Future of Space Innovation.

The day started with Dr. Alistair John, founder of Race2Space and programme lead for Aerospace Engineering at the University of Sheffield.

The first of the fireside chats was with Felix Barr who talked with Pete about his military career in space R&D with the US Air Force and his work on spacecraft development for Motorola’s Iridium satellite program.

The second fireside chat was with fellow ISEC Director, Adrian Nixon, who guided the conversation towards the future of space innovation, materials technology, and the space elevator.

If you wish to know more about this event, the organisers posted a link at Eventbrite to advertise it:

https://www.eventbrite.co.uk/e/horizons-beyond-fireside-chats-on-the-future-of-space-innovation-tickets-1047812925667?aff=oddtdtcreator

Space Elevator Speakers Bureau

Do you consider yourself a space elevator expert or enthusiast? Are you well-informed on any aspect of the space elevator? Are you good at explaining things? If any of these things are true, considering joining the ISEC Speakers Bureau. We are launching a new effort, headed by Larry Bartoszek (larry.bartoszek@isec.org), to bring the discussion of space elevators to your local community. We’re compiling a list of volunteer speakers who will be available for speaking at local groups such as science/astronomy clubs, seniors organizations, Rotary, Lions, or other business and community groups. We also plan to provide a collection of presentation materials for speakers to draw on.

Speaking from experience, this is a lot of fun. Every group I’ve spoken to is both very interested and quite appreciative to hear about such things. It also sometimes happens that within the audience there are people with a keen interest who are looking for a way to contribute. It’s gratifying to get these people connected.

Please contact Larry if you’d like to get involved.

Dennis Wright

ISEC and KIST Present at the MMCA Space Symposium in Seoul, South Korea

In South Korea, the National Museum of Modern and Contemporary Art (MMCA) has a programme of events during 2024 about space; ISEC was invited to present about the Space Elevator project. We were presenting with the prestigious Korea Institute of Science and Technology (KIST) who have a programme of work on ultra strong materials.

Pete Swan, John Knapman, and Adrian Nixon were invited to present the latest developments in the design, research topics, and materials technology for the space elevator. This was a live event in Seoul, South Korea, and we presented via Zoom and took questions from a panel of experts from KIST as well as questions from the audience.

Pete Swan presenting about the architecture of the space elevator with John Knapman and Adrian Nixon following with their presentations.

The event was a big success, and we seem to have impressed those who’d attended.

In a follow up message Dr. Bon-Cheol Ku from the Korea Institute of Science and Technology (KIST) passed on his thanks to us for making the Space Elevator Symposium a success. We discovered that he is genuinely enthusiastic about the prospect of realizing the Space Elevator within the next 20 years. We were also informed that KIST Jeonbuk, are committed to advancing ultra strong tether materials to support this vision.

We are now working out how to keep in touch with KIST and exploring ways we might work together. This highlights the importance of making the effort to plan, prepare and deliver presentations on the international stage. There is a lot more support around the world for this technology than we realise, and we can extend the community of like-minded experts by doing this kind of outreach.

Solar System Space Elevators

by Peter Robinson

Part 5: Jupiter and Jupiter’s Moons

This is the fifth article of the “Solar System Space Elevators” series. Earlier articles covered Mercury & Venus, the Asteroids, the Moon, and Mars.

1. JUPITER

Jupiter is “big … vastly, hugely, mind-bogglingly big …” (with apologies to Douglas Adams).

Figure 1: Jupiter, the Earth, and the Moon. Credit NASA & Wikipedia Commons.

The scale of Jupiter led me not to consider an Elevator to the Jupiter ‘surface’ until recently, but I decided I should check the numbers after reading Stephen Baxter describe a gas giant elevator in his SF Novel Creation Node; see my review in the April-2024 ISEC newsletter [1].

Jupiter’s nominal equatorial radius is 71,492 km (11.2 x Earth), with a mass of 317.8 x Earth, a rotation period of 9.925 hours and an equatorial ‘surface’ gravity of 2.528 x Earth. These combine to yield a stationary altitude of 88,517 km, meaning any elevator would need to be at the very least 100,000km long.

Spreadsheet analysis (see earlier articles in this series) shows that Graphene Super Laminate (GSL) material with a working specific stress of 38.9 MYuri (88 GPa at 2260 kg/m^3) would require a taper ratio of 24,743,998: 1, meaning that a tether with area 10 mm^2 (1m x 10 micron) at Jupiter’s surface would need to have an area of over 240 m^2 at the stationary altitude … so 1m wide and 240+m thick! This is clearly not feasible; a stronger material is needed!

Figure 2 below shows the effect of increasing the tether specific strength on the taper ratio, calculated using the Pearson taper equation [2].

Figure 2: Tether Taper Ratio v Specific Strength. Analysis: P. Robinson.

A taper ratio of less than ten might avoid the total tether mass becoming excessive, meaning a material specific strength of over 300 MYuri would be needed. This is almost eight times the forecast strength of GSL, and I am not aware of any material which could even theoretically approach this strength.

Among other issues with a Jupiter Elevator is the lack of any solid surface, meaning that the tether base would need to be a suspended mass. This would lead to stability and dynamic control challenges, especially when considering the high wind velocities in the Jovian atmosphere. Potential methods to counter wind loading are discussed in the 2017 article by Brandon Weigel in Medium [3]: this describes a ‘short’ (2000 km) elevator from the upper areas of the Jovian atmosphere to an orbital station, with both ends incorporating propulsion systems.

A Space Elevator on Jupiter is thus not feasible with current or foreseen technologies, so I will not include any further analysis.

2. JUPITER’S MOONS

2.1 The Galilean Moons

Jupiter has 95 moons with confirmed orbits, and hundreds more km-sized moons and smaller moonlets. The four largest moons are Io, Europa, Ganymede and Callisto, first observed and recognized as satellites of Jupiter by Galileo Galilei in 1610. All are tidally locked to Jupiter, meaning they are candidates for ‘L1-type’ space elevators, see my ‘Luna’ article in the August 2024 newsletter [4].

Figure 3: The Galilean Moons (Io, Europa, Ganymede, Callisto). Credit Wikipedia Commons.

Basic parameters are as follows, ref [5] [6] [7] [8]:

2.1.1 IO

Orbit Radius = 421,700 km from Jupiter
Orbital Period = 1.77 days
Diameter = 3,643 km (168 km more than Earth’s Moon)
Surface Gravity = 0.183 g
Atmospheric Pressure: 0.5 to 4 mPa
L1 Altitude = 8,650 km (15% of that of Earth’s Moon)

Thus, a Space Elevator on Io could be shorter than a Lunar Elevator, perhaps 20,000-30,000 km depending on the Apex Anchor mass.

Unfortunately, several environmental factors would make construction, durability, and operation extremely difficult: Io’s surface is highly volcanic (400 active sulphur volcanos), and the space environment is hostile due Jupiter’s powerful magnetosphere and associated radiation levels [5]. The interaction of a tether with the Io flux tube and other phenomena would require thorough analysis, with potentially very high induced voltages and currents.

2.1.2 EUROPA

Orbit Radius = 670,900 km from Jupiter
Orbital Period = 3.55 days (orbital resonance with Io)
Diameter = 3,121 km
Surface Gravity = 0.134 g
Atmospheric Pressure: 0.1 micro-Pa
L1 Altitude = 11,900 km

The length of any Elevator on Europa might perhaps be in the range 25,000 to 35,000 km, but high radiation levels would still be a major concern. Surface radiation levels could cause death to a human within 24 hours [6].

The ice surface of Europa might be sufficiently stable for attaching a ground station, but the ambient temperature range of 50-125 K would require mitigation. Tectonic activity would need to be assessed.

Spoiler alert: we must not forget the warning from Arthur C Clarke in 2010: Odyssey Two: “… ALL THESE WORLDS ARE YOURS, EXCEPT EUROPA. ATTEMPT NO LANDING THERE …”!!

2.1.3 GANYMEDE

Orbit Radius = 1,070,400 km
Orbital Period = 7.15 days (orbital resonance with Europa and Io)
Diameter = 5,268 km
Surface Gravity = 0.146 g
Atmospheric Pressure: 0.2–1.2 micro-Pa
L1 Altitude = 29,700 km

Ganymede is the largest satellite in the solar system, larger than Mercury. The L1 altitude means that any elevator would be substantially longer than that needed for Io or Europa, but still shorter than that required for Earth’s Moon.

The radiation environment is less severe than Europa (fatal after months rather than days), but still of concern. The surface conditions are believed to be stable and probably suitable for tether attachment, although the low temperatures (70-152 K) may be troublesome.

2.1.4 CALLISTO

Orbit Radius = 1,883,000 km
Orbital Period = 16.7 days
Diameter = 4,820 km
Surface Gravity = 0.126 g
Atmospheric Pressure: 0.75 micro-Pa
L1 Altitude = 47,400 km

Callisto is “less affected by Jupiter's magnetosphere than the other inner satellites because of its more remote orbit, located just outside Jupiter's main radiation belt” [8]. This environment makes it a better candidate for a Space Elevator, although the higher L1 altitude means any tether might need to be in excess of 100,000 km.

Figure 4 below shows Tether and Apex Anchor (Counterweight) masses for an arbitrary Callisto tether design.

Figure 4: Tether & Apex Anchor (CW) Masses. Analysis: P. Robinson.

The above analysis assumes GSL material with a working stress of 15 GPa, less than required for the Earth and the same as I proposed for a Mars Elevator [9]. The cross-sectional area is fixed at a low value of only 3 mm^2 (perhaps 0.5m x 6 micron), sufficient for supporting a 5 tonne climber with some surface retention margin. For a higher surface retention force or heavier climbers, the area and masses would increase pro rata, unless the working stress is increased.

The counterweight masses shown above are high and would make a Callisto elevator construction challenging (as for Earth’s Moon), although mass for the Anchor could perhaps be gathered from the plentiful supply of orbital material around Jupiter.

A Callisto elevator tether could in theory be manufactured using an existing strong synthetic polymer such as Zylon. Such a tether might have more mass than a GSL tether and a lower safety margin due to the material operating close to its ultimate strength. One paper suggests that the physical strength of Zylon is not reduced at the low temperatures of the Jupiter environment, but other sources state that strength is significantly reduced by exposure to light and UV radiation.

2.2 Other Moons

Jupiter hosts four other ‘regular’ moons (Metis, Adrastea, Amalthea and Thebe), these are all within the orbit of Io and with diameters from 20km to over 200km. The extreme radiation environment close to Jupiter means that these are not suitable candidates for a space elevator, or for any human or robotic activity in the likely future.

The many other moons of Jupiter are ‘irregular’, beyond Callisto with eccentric and distant orbits. All are probably captured asteroids, so my earlier article on ‘Asteroid’ elevators is applicable: in summary, surface integrity may be inadequate for retention of an Elevator system, but in any case, other access options (such as rockets or mass drivers) are likely to be more economic.

3. DIGRESSION - a Mathematical Challenge

The above analysis used a constant-area tether, resulting in a higher tether mass than a tapered design. I am not aware of an equation precisely defining the constant-stress taper ratio for an ‘L1’ type Space Elevator, the Pearson taper equation [2] being solely for a centrifugal-type elevator subject to gravity forces from a single body. Any ‘L1-type’ equation would need to cater for the gravity of two bodies: the primary and the moon. Is this a challenge that any readers would like to accept?

An approximate constant-stress profile could be found numerically, but I did not include this extra complexity in my spreadsheet.

Perhaps there is an equation defined in some earlier work; if so, I would appreciate hearing about it.

4. SUMMARY

A Space Elevator on Jupiter itself would require a tether material almost an order of magnitude stronger than that forecast for GSL, which itself is substantially stronger than any current mass-produced material. The extreme radiation environment and high atmospheric winds also suggest that it could be many centuries before an elevator might become feasible.

The adverse radiation environment and other factors would also make an elevator challenging on the four inner moons and the first three Galilean Moons. The fourth large moon (Callisto) would be technically less difficult, but the necessary length (100,000+ km) and high Apex Anchor mass for a relatively low lift capacity means that construction of an Elevator is unlikely to be economically or logistically viable.

All of Jupiter’s moons have little atmosphere (pressure data above), making alternative surface access methods such as rockets or mass drivers more practical. In the case of arriving spacecraft the fuel cost of a rendezvous with some point on the space elevator might be less than the fuel cost of landing on a moon surface, but the time and cost of a ‘climber’ descent to the moon surface must be considered.

In conclusion: I am not convinced that building a space elevator will be a viable solution anywhere in the Jupiter system in the foreseeable future.

NEXT TIME: more positive … Saturn, Titan and Enceladus

REFERENCES

[1] ISEC April-2024 Newsletter, https://www.isec.org/space-elevator-newsletter-2024-april

(‘Creation Node’ by Stephen Baxter, published by Gollancz, Sept 2023, ISBN-13: 978-1473228955 )

[2] “The orbital tower: a spacecraft launcher using the Earth’s rotational energy”, J.Pearson, 1975 Acta Astronautica Vol. 2. pp. 785-799, https://linkinghub.elsevier.com/retrieve/pii/0094576575900211

[3] “A Space Elevator … on Jupiter?”, Brandon Weigel, Medium, August 2017: https://medium.com/our-space/a-space-elevator-on-jupiter-415497c56281

[4] ISEC August-2024 Newsletter, https://www.isec.org/space-elevator-newsletter-2024-august/#solarsystem

[5] Io Wikipedia page: https://en.wikipedia.org/wiki/Io_(moon)

[6] Europa Wikipedia page: https://en.wikipedia.org/wiki/Europa_(moon)

[7] Ganymede Wikipedia page: https://en.wikipedia.org/wiki/Ganymede_(moon)

[8] Callisto Wikipedia page: https://en.wikipedia.org/wiki/Callisto_(moon)

[9] ISEC September-2024 Newsletter, https://www.isec.org/space-elevator-newsletter-2024-september/#solarsystem

Tether Materials

by Adrian Nixon

Making Graphene from Molten Metal

In the previous newsletter [1], my article proposed that graphene will be detected on the planet Mercury. Large crystals of graphene super laminate (GSL), i.e. single crystal graphite, might be detected from space by orbiting satellites.

This has prompted a challenge by some readers to explain how crystals of GSL could become so large given that the graphene that had been detected on the surface of the Moon was derived from meteorites and the crystal size was very small.

There were two sources in the literature that point in the direction of large crystals of graphene forming.

The first is from Canada. The Manitoba Mineral Society identified unlabelled specimens from Baffin Island, on display at the Canadian Museum of Nature, Ottawa, Canada [2]. One of these samples is a collection of graphite crystals that are from 10 to 15 centimetres (4 to 6 inches) high. They are silvery metallic and highly reflective.

Fig 1. 10 to 15 centimetre high graphite crystals from Baffin Island, on display at the Canadian Museum of Nature, Ottawa, Canada. Image credit: Mike Beauregard, Wikipedia.

The Baffin Island specimens show that very large crystals of graphite can form naturally. There is some uncertainty about how these crystals form. Some sources suggest that hydrothermal processes can form graphene and graphite [3]. Other sources show that graphene can form from dissolved carbon in molten metal [4].

When it comes to the planet Mercury, hydrothermal vents are unlikely as water is not present in large amounts on the planet. There is a large amount of iron and carbon on Mercury [5], so we know that the precursors for graphene formation are present. We also know that the size of crystals is directly proportional to the time taken for them to form. The longer a crystal takes to form the bigger it is [6].

So, secondly, have large crystals of graphene super laminate ever been made? Surprisingly, the answer is yes.

Large single crystals of graphite have been made in a laboratory. The work was done back in the 1960s [7]. Researchers at Atomics International, a division of North American Rockwell Corp., reported that, “Graphite single crystals were grown by precipitation from carbon-saturated molten iron and nickel. They were grown with low nucleation and growth rates under conditions of low supersaturation, using slow-cooling and steady-state thermal gradient methods. Crystals that were produced included thin platelets up to 3 cm across and a fraction of a millimeter thick, tabular crystals measuring several millimeters across.”

These crystals were silvery metallic in appearance and highly reflective. The paper reports that the crystals were grown from molten metal at temperatures between 1200-1500” C. They ran 27 experiments, producing the crystals over periods of several days.

Given more time, these crystals would grow to be much bigger. On a planetary scale geological processes take place over millions of years and could lead to the formation of very large single crystals of graphene super laminate.

The planet Mercury has the raw materials and the required conditions for very large single crystals of graphene and graphene super laminate to form. Once formed, graphene is extremely stable and will persist for billions of years [8]. This is why I am predicting that graphene will eventually be found on the planet Mercury.

References

1. Nixon, A. (2024a). ISEC Newsletter: Tether Materials - A Prediction: Graphene Will be Found on the Planet Mercury. [online] International Space Elevator Consortium. Available at: https://www.isec.org/space-elevator-newsletter-2024-october/#tether [Accessed 27 Oct. 2024].

2. Beauregard, M. (2011). File: Kimmirut Graphite.jpg - Wikimedia Commons. [online] Wikimedia.org. Available at: https://commons.wikimedia.org/wiki/File:Kimmirut_Graphite.jpg [Accessed 27 Oct. 2024]. World-class graphite crystals in standing sheets 10 to 15 cm high. Unlabelled specimens from Baffin Island, on display at the Canadian Museum of Nature, Ottawa, Canada.

3. Al-Ahmed, A. and Inamuddin (2022). Graphene from Natural Sources. Boca Raton: CRC Press, pp.15, 19. doi:https://doi.org/10.1201/9781003169741.

4. Amini, S., Garay, J.E., Liu, G., Balandin, A.A. and Reza Abbaschian (2010). Growth of large-area graphene films from metal-carbon melts. Journal of Applied Physics, 108(9), pp.094321–094321. doi:https://doi.org/10.1063/1.3498815.

5. Xu, Y., Lin, Y., Wu, P., Namur, O., Zhang, Y. and Charlier, B. (2024). A diamond-bearing core-mantle boundary on Mercury. Nature Communications, [online] 15(1). doi:https://doi.org/10.1038/s41467-024-49305-x

6. Stein, S. (2023). Cooling Rate and Crystal Size | Seth Stein. [online] sites.northwestern.edu. Available at: https://sites.northwestern.edu/sethstein/a-small-is-beautiful-approach-to-upgrading-a-beginning-geophysics-course/cooling-rate-and-crystal-size/ [Accessed 27 Oct. 2024].

7. Austerman, S.B., Myron, S.M. and Wagner, J.W. (1967). Growth and characterization of graphite single crystals. Carbon, 5(6), pp.549–557. doi:https://doi.org/10.1016/0008-6223(67)90032-2.

8. Ohtomo, Y., Kakegawa, T. and Sato, T. (2023). Transparent carbon films containing graphene in 3.2 Ga sedimentary rocks in the Moodies group, Barberton Greenstone Belt, South Africa. In: Goldschmidt, Lyon 2023. [online] Goldschmidt 2023. France: Goldschmidt. Available at: https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi/Paper/15032 [Accessed 17 Nov. 2023].

Social Media Update

Our social media presence on LinkedIn continues to grow, now with over 2050 followers…BUT we recognise that not everyone has a LinkedIn account, despite the glowing recommendation from our editor last month.

To maximise engagement and continue spreading the word about space elevators we may need to diversify to alternative platforms, so we looked at the total number of app downloads from the Google store to give us a simple indication of relative popularity. Here are the Android app download numbers in descending order:

Facebook 10B+
Instagram 5B+
LinkedIn 1B+
X (Twitter) 1B+
Threads 100M+
BlueSky 5M+
Flickr 1M+
Mastodon 1M+

(We realise this doesn’t include downloads of apps for Apple, PC or other platforms, but the sample size is statistically more than large enough)

Looking down this list… we have previously asked for help on Facebook, but for some reason it often defeats us! Instagram is primarily for photos, and we post there when we can. LinkedIn is next, with over 1 billion users (according to Wikipedia), and with our posts always attracting far more responses than on other platforms.

The newest platform is Bluesky. Developed by former Twitter CEO Jack Dorsey as a decentralized version of Twitter, it was spun off after the Musk take-over and finally launched for public registration in February 2024. According to Wikipedia it is “considered a major competitor to X/Twitter, alongside Mastodon and Threads”, with over 20 million users at the time of this publication! (If you would like to follow updates on the growth of new Bluesky members, here's a link to a live counter! https://bsky-users.theo.io/) 

Therefore…

BREAKING NEWS: ISEC now has a Bluesky account!! You will now find it listed on our social media web page https://www.isec.org/social-media, but here’s a direct link: https://bsky.app/profile/isecdotorg.bsky.social

We are constantly reviewing our social media participation. Newsletters will continue to be posted monthly on every platform, but much more goes on LinkedIn. You can help guide us further on your preferred platform by following us, and by engaging with our posts through ‘likes’, ‘re-posts’, or comments.

ISEC Media Mogul

Around the Web

From the Royal Society:

https://www.bbc.com/videos/c62d9zp9074o

Space Elevators are first, but the rest of the video pertains to us as well since space elevators can assist with those goals.  

https://www.thesun.co.uk/tech/31365631/ways-travel-to-space-elevator-baloon-tourists/ 

Upcoming Events

IPSPACE 2024
https://iaaspace.org/event/international-symposium-on-the-peaceful-use-of-space-technology-health-2024/
Theme: Peaceful Use of Space Technology - Health
Tuesday, December 3rd, through Thursday, December 6th, 2024
Hainan, China

International Space Development Conference 2025
Sponsored by the National Space Society
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https://isdc.nss.org/
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Rosen Center, Orlando, FL, United States

76th International Astronautical Congress
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Monday, September 29th, through Friday, October 3rd, 2025
International Convention Centre, Sydney, Australia

77th International Astronautical Congress
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Theme: “The World Needs More Space”
Proposed Dates: October 5th through October 9th, 2026
Antalya, Turkey

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