Are space elevators realistic?

In 1895, Konstantin Tsiolkovsky, the grandfather of astronautics, proposed for the first time the concept of space elevator. Since that time, there was considerable skepticism towards this concept. However in December 2013, the International Academy of Astronautics “Concludes Space Elevators Seem Feasible” as described in the book “Space Elevators: An Assessment of the Technological Feasibility and the Way Forward”.

Will we ever see an astronaut exploring space launched by a space elevator?

Alternative launching system

A space elevator is a mass transport system to reach space. The concept consists of a very long cable attached near the equator of the planet and extended into space beyond geostationary orbit. Most current concepts are proposed for Earth implementation but it could take place on another planet. This alternative to large rockets would be an asset for space exploration.

In 2003, Dr. Bradley C. Edwards established guidelines for the construction in his book “The Space Elevator: A Revolutionary Earth-to-Space Transportation System”. Most of designs include four basic elements:

  • Anchor station: an anchor that could be on mobile a platform in the ocean or static on the top of a mountain. The location will be preferably near the equator in order to benefit of natural Earth velocity.
  • Ribbon: it has to support a colossal tension which varies with the altitude and a large weight (its own weight and the climber). It is a guide for the climber.
  • Climber: in that case, the cable doesn’t pull the cabin, it must climb by itself. It could carry payloads and crew to space for Earth orbit or for further space destinations. A good velocity is 200 km/h which means a 180 hours (<8 days) trip to geosynchronous orbit (36 000km).
  •  Counterweight: it could be a space rock or a specific station. Earth’s rotation creates upward centrifugal force on the counterweight. Cargo carried from the surface would allowed to be launched into interplanetary space thanks to the considerable velocity gained relatively to the Earth.
Space elevtor mechanics - Credits: unkwon

Space elevtor mechanics – Credits: unknown

Once the expensive job of building the elevator is completed, an indefinite number of loads can be transported into orbit at reduced cost.

This machine could carry payload and human into space, up to geostationary orbit and beyond. The ascension would be less stressful for the human body, safer and cheaper on a routine basis. It is a nice opportunity to make space more accessible to a larger amount of people.

The cost of a space elevator

In his book Leaving Earth (2013), Andrew Rader provides some numbers about big building projects:

“Other notable megaprojects in this price range include (2013 dollars): the Manhattan project ($26 billion), the English Channel tunnel ($17 billion), the Boston “Big Dig” tunnel system ($15 billion), the Arabian canal ($11 billion), the John F. Kennedy airport expansion ($10 billion), the Yucca mountain nuclear waste depository ($9 billion), and the Atlanta-Jackson airport expansion ($9 billion).”

Current estimations start from US$6 to US$20 billion for building one space elevator from Earth’s equator to geostationary orbit. This prices includes: in orbit construction, ribbon, power beaming stations, climbers, anchor station, tracking facilities, insurance, testing and contingency. This budget fits into the range of similar super structures and should provide some revenue.

Currently, the cost for sending a cargo to the geostationary orbit with a thermal rocket is around US$20 000/kg and the cost to send a cargo with a space elevator would be around US$250/kg (Edwards). Most of the price covers the power supply, the maintenance and the operating. It is not crazy to imagine a return on investment within 10 years.

The challenge

Space elevator - Crédits: unkwon

Space elevator – Crédits: unknown

Currently, there are many technologic challenges to build a space elevator. It might be difficult to see such a structure in a near future. Scientists and engineers should fix some remaining problems:

  • The construction of the ribbon: currently, there is not any existing material with a sufficient high tensile strength and with low density capable to comply with the structure requirements yet.
  • Prevent the swing: the ribbon and the climber will undergo some swing generated by the gravitational effect from the Moon and the Sun. It will also suffer from the Coriolis Effect (problem also evocated in the article about artificial gravity).
  • Risk of collision: that will have an impact on the air traffic. Plus, there is a risk of impact with a space object (satellites, debris, meteorites, …)
  • Environmental damage: the system will suffer from corrosion and radiation.

All those problems will jeopardize the total integrity of the space elevator. However, many researches are conducted all around the world about those topics. Astronauts will not escape from the Earth’s gravity via a space elevator tomorrow but we prefer to believe that it’s remain possible.

Next big conference about space elevators takes place in Seattle (USA), August 22-24, 2014 – ISEC Space Elevator Conference

Space elevator and fiction

Space elevators are also very popular in fiction. Sci-Fi novels, fairy tails, anime, manga and comics are fond of crazy technologies and often precursors of innovation: Jules Verne and Hergé went to the Moon a long time before the NASA. Star Trek’s TOS communicator has been inspiration for the first handheld mobile phone. It has also a large place in futuristic games like Syndicate Wars, Civilization IV and, Halo. However, it is underrepresented in TV series and movies: Star Trek and Doctor Who save the situation.

Because we are all Born For Space!

9 thoughts on “Are space elevators realistic?

  1. One thing rarely mentioned about space elevators: Propellant-wise, this is not “free escape”. The counterweight must still expend propellant maintaining orbit. Otherwise every trip up will degrade the counterweight’s orbit so that PE gained by climber and payload equals PE lost by the counterweight. The advantage of the space elevator is vastly reduced drag that must be compensated for, and the fact that the propellant expenditure can be spread over time. This allows for possibly higher efficiency thrusters, and opens the possibility of combining the system with another exciting future technology: an in situ propellant accumulator.

  2. …space-elevator (orbital station bike wheel-1g)… geostationary orbit, a huge “bike-wheel” is gyrating around its own axis for have 1g-centrifugal. Wheel held in place with 4 CABLES (each cable with a track for Train, for both train´s/crossing ↓↑) FORMING THE STRUCTURE OF A RHOMBUS♦ (minor diagonal of rhombus is the gyration-axis of the Station-Wheel)…rhombus´s below, the carbon nanotubes Track towards Earth…rhombus´s above the Cable towards the higher counterweight… if…WHEEL´s RADIUS = 250 mts… Wheel gyration´s Axis length = rhombus´s minor diagonal = Wheel´s radius = 250 mts. Cable´s length of the rhombus´s side = Wheel diameter = 500 mts. Wheel´s ZONE-1g: habitable length = 1571 mts* 50 mts wide*50 mts height, gyrating 360º each 31 seconds, angular-speed = 11.61º/sec, linear-speed = 182 kms/h… Station-Wheel´s GYRATION: AXIS IN PERPENDICULAR (90º) ORIENTATION TO ORBITAL TRAJECTORY…and so, while Station-Wheel follows its geostationary orbit, the Wheel does Not changes the spatial orientation of its axis, and thus there are Not Precession forces actuating (and thus there is Not collision tendency of the Station-Wheel against the rhombus´s cables… Wheel with maneuver´s tangential-rockets for gyration´s-starts, or…gyration emergency stop…but the system must counteracting or supporting lateral charges against Track produced by the Coriolis effect when Train goes upwards or downwards…and so maintaining the Track always without transverse lateral↔movements, the gyroscopic-rigidity contributes for maintaining forever the gyration-axis perpendicular to orbital trajectory… When the Maglev Train slowly arrives, using now their retractable cogwheels by the Zipper-Track (zippers installed on the same Maglev-Track), Train stops in Geo 0g-Station placed over one extreme of the gyration-axis… Passengers disembark and entering into gyratory circular corridor, they take now the interior-elevator of one of the Wheel´s hollow-radius, and tunnel “descending” till Hotel into the final Zone-1g…where while Station-Wheel goes turning, the immense O2 producer Hydroponics Garden receives a filtered Sun light…and there are Earth´s awesome views.

  3. ☼↓↓▓0.08g▬▬▬←▬▬▬▬▬↓Moon▬▬♦1g▬→▬▬1g…Space-elevator (orbital station ramp)… Faraway high beyond Earth surface at 150,000 kms…fast orbital speed 11.4 kms/sec…with only 0.08g centrifugal, 0.8 mts/sec² (a person who has 80 kgs ↓ gravitational force on Earth equator radius=6378.1 kms; over there with a radius=156378.1 kms only has 6.64 kgs ↑ centrifugal force…gravitational force downwards minus centrifugal force upwards)…could be the counterweight Terminal Orbital Station-Ramp… Awaits passengers in Earth-Station a hyperspeed vertical electric Train of Magnetic Levitation… “Spatial Train coming from Orbital Station-Ramp and Orbital Station-Wheel at these moments arriving will depart again after one hour, passengers with Moon destination please embark on SHIP-COACH when will be hooked at Train´s end”… (((if…Train´s mass=1000 Tm and its vertical max-speed=10000 kms/h…CORIOLIS´s EFFECT AGAINST TRACK ↓to East, ↑to West: acceleration=0.4 mts/sec², FORCE=41 Tm… How Track is attached on Earth´s equator, this lateral Thrust occur in the same orbital plane, forward or backward, and thus almost there is Not Precession´s problems in the System…except because due to slight orientation´s changes (nutation, etc) of Earth´s axis, would that doing each a certain time a little correction, with their own axial maneuver´s rockets, for reorientation of Wheel´s axis)))…medium-speed = 5,000 kms/hour: Earth/Orbital Station-Wheel, distance = 35,786 kms…total travel time = 7 hours… Orbital Station-Wheel/Orbital Station-Ramp, distance = 114,214 kms…total travel time = 23 hours… Well seized from retractable cogwheels, with slow-speed at the beginning travel of strong gravitation from Earth, with conventional Zipper-Track… THE TRAIN DEPARTS►… “Passengers please belts”…starting horizontal from Station, when train goes climbing is VERTICAL, looking upwards… vertical train with special zig-zag corridor with protections and seats also in the center for avoiding passenger´s fall down in straight line till coach´s bottom… Already enough far, with little gravitational Earth attraction: MAGLEV on…Cogwheels off… Here we go…goooooo!…hyperspeed→… Already braking enough near from each Station…slow-speed, changes propulsion system again: COGWHEELS on…Maglev off… Entering in slow track on rhombus structure… 7 hours: half length above half length below through Station´s floor, Train is on rhombus inclined track at zero-speed, near from Water-Recycling Plant with carbon nanotubes´s filters…and the other Air-Filtering Plant with catalysts…the passengers disembark in weightlessness: Geo 0g-Station…passing from static-platform to gyratory circular corridor, go taking soon an interior-elevator in one of the hollows-radius and “descending”…finally, the passengers have arrived at destination: Wheel centrifuge 1g-Station, with its gyration´s-axis perpendicular to orbital trajectory… A Wheel with 500 mts diameter, 1g-habitable length 1571 mts*50 mts wide*50 mts height…gyrating into 4 cables, each cable with a track for Train, a rhombus structure forming for Wheel´s supporting…

  4. (2) space-elevator (orbital station ramp)… Tour continuing again… THE TRAIN DEPARTS►… once passed the slow zipper-track on rhombus structure, enters again on fast maglev-track… km 50,630, braking: Moon-Launching-Point, Train is at zero-speed, rear SHIP-COACH is released staying alone, again… THE TRAIN DEPARTS►… (((SHIP-COACH, while Earth turns, awaits patient the hour for releasing from Track and going to Moon with exact heading…now…takeoff and goes transferring orbits till Moon orbit where firing rocket again brakes and lands on Moon-Station… “Come to occult face with us and visiting the ancient Alien in ruins City”…and once recharged with fuel and passengers…equal than aircraft carrier, from a Launching-Catapult… SHIP-COACH TAKEOFF►… and returns conventionally to Earth)))… Already enough near from Terminal (magnetic shield anti-radiation and UV rays protection)…slowly by zipper-track maglev and train´s cogwheels are braking strongly “downhill”… 23 hours: Train is horizontal on Terminal at zero-speed, near from Ship´s Launching-Ramp towards Jupiter/interstellar Space, in spectacular and covered by transparent graphene´s domes with Earth views always in the ceiling, the passengers disembark at destination: counterweight centrifuge Ramp 0.08g-Station.

  5. (2)…space-elevator (orbital station bike wheel-1g)… if…WHEEL´s RADIUS = 250 mts… Wheel gyration´s Axis length = rhombus´s minor diagonal = ¼ Wheel´s radius = 62.5 mts (axis could be a resistant hollow tube with for example 5 mts in diameter with an adequate wall´s thickness, hollow which could serving how tank of anything, e.g. air, or tank of frozen water storage no totally full, for volume expansion from liquid to ice without tank, Axis, breaking, thawing using solar-heat)… Cable´s length of the rhombus´s side = Wheel diameter = 500 mts. Wheel´s ZONE-1g: habitable length = 1571 mts*50 mts wide (separation at both sides between Cable and Circumference of the gyratory Wheel, approx.= 5 mts, adjusting this separation installing an Axis with major or minor length, as much as shorter Axis…stronger and an angle nearer to 180º value, for easy train´s passing, in both rhombus´s vertex where are the Big Soundless-♫-Bearings of Axis´s-insertion…a few Electrical Motors fed with Solar-Energy maintain automatically the gyration-speed counteracting the slow braking by friction from the Bearings…besides of Bearings: main system Maglev also for the gyration and Axis´s supporting, leaving the Bearings only how secondary security system?…with a slight roominess between each Bearing and its exterior subjection, into the roominess all around…little solid pistons extensible and retractable… Axis´s subjection: extensible ON, with Bearings; extensible OFF, with Maglev. With a sufficient cables tension coming from the counterweight, if Axis resists: the rhombus structure is undeformable)*10 Floors with 25 mts in height each one, gyrating 360º each 31 seconds…a person with 80 kgs mass, would have in each Floor a centrifugal force:… Floor 1: 1.04g=84 kgs… Floor 2: 0.94g=75 kgs… Floor 3: 0.84g=67 kgs… Floor 4: 0.73g=59 kgs… Floor 5: 0.63g=50 kgs… Floor 6: 0.52g=42 kgs… Floor 7: 0.42g=34 kgs… Floor 8: 0.31g=25 kgs… Floor 9: 0.21g=17 kgs… Floor 10: 0.1g=8.4 kgs…it gyrating into 4 cables, each cable with a track for Train, a rhombus structure forming for Wheel´s supporting…

    • …if WHEEL´s RADIUS = 250 mts: Wheel gyration´s Axis length = rhombus´s minor diagonal =…(((for have approx.= 5 mts separation between Cable and both sides of Wheel´s Circumference, with only ¼ Wheel´s radius=62.5 mts, each semi-Wheel would must have a trapezoidal section with a wide of 50 mts at center and 20 mts at circumference)))…= ½ Wheel´s radius = 125 mts (axis could be a resistant hollow tube with for example 20 mts in diameter

  6. (4)…space-elevator (orbital-station bike-wheel-1g)… also how Wheel´s supporting, instead of a rhombus, can be a narrow Rectangular structure ▄▄▄▄▄▄ of rigid girder with dimension sides slightly majors than Wheel´s diameter and wide, e.g. Wheel´s diameter 500 mts and wide 50 mts…rectangle´s sides: 510 mts length, 60 mts wide. Rectangle with a cable/track (length=Wheel´s diameter) in each vertex, forming a long isosceles triangle ───◄at both rectangle´s minor sides►───.

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