A space elevator

How far are we from a space elevator?

A space elevator would be a cable anchored on Earth and extending into orbit, with climbers carrying cargo along it. NASA-linked papers from 2000 and 2005 discuss the concept, and the 2005 paper names the tether material as the key technology. No tether-length material has been shown. The 2022 IAC paper gives 0.5 metre as the longest carbon nanotube made, and a 2025 review reports drawn carbon-nanotube fibres with tensile strengths up to 4.6 GPa, a long way from the 100 GPa range NASA set for ribbon composites. A 2009 NASA power-beaming contest was won by a light-powered climber on a one-kilometre cable, which is not an orbital tether.

AI illustration · Illustrative scene, not a photograph of the specific device or experiment.
WHERE WE AREScience unproven

Very far away. The basic science has not been shown to work.

The concept has been assessed, but the central material has not been shown at tether scale. NASA's 2005 review names ultra high strength carbon nanotube composites for ribbon construction, in the 100 GPa range, as the most critical technology for earth-based space elevators. A 2025 review reports carbon-nanotube fibres with tensile strengths up to 4.6 GPa in the laboratory, and the 2022 IAC paper says tether-quality material still needs more development. No reviewed source shows a material of tether length and tether strength, so the stage is not higher than science-unproven.

The tech tree

Everything recorded on Vrulum that this future needs, oldest foundations at the top and the goal at the bottom. Lines show what each step requires.

What it takes: A space elevator Unlocked Being researched Locked
  1. 2017Asteroid miningResearch and prototypes Being researched.
  1. 2014In-space manufacturingResearch and prototypesRequires: Asteroid mining. Being researched.
  1. 1964Reusable launch vehiclesPilot and early commercialRequires: In-space manufacturing. Unlocked.
  1. 1987Mechanical metamaterialsLab demonstration Being researched.
  2. 2023Space-based solar powerResearch and prototypesRequires: Reusable launch vehicles, In-space manufacturing. Being researched.
  1. 2005Feasibility assessments publishedDone Unlocked.
  2. 2009Power-beamed climber run on a one-kilometre cableDone Unlocked.
  3. 2012Construction route for the tether chosenIn progress Being researched.
  4. 2025Tether material with the required strength demonstratedIn progress Being researched.
  5. 2026Climber power options compared in system analysisIn progress Being researched.
  6. Date not recordedTether-grade material produced at kilometre lengthsNot started Locked.
  7. Date not recordedFull-length tether tested in orbitNot started Locked.
  8. Date not recordedGround anchor and Earth-to-orbit cable builtNot started Locked.
  9. Date not recordedOperational elevator carrying cargo to orbitNot started Locked.
  1. GoalA space elevatorGoalRequires: Reusable launch vehicles, Mechanical metamaterials, Space-based solar power, Asteroid mining, Feasibility assessments published, Tether material with the required strength demonstrated, Tether-grade material produced at kilometre lengths, Construction route for the tether chosen, Power-beamed climber run on a one-kilometre cable, Climber power options compared in system analysis, Full-length tether tested in orbit, Ground anchor and Earth-to-orbit cable built, Operational elevator carrying cargo to orbit. Locked.

The road so far

2 of 9 steps done, 3 in progress.

  1. Done · 2005Feasibility assessments published

    NASA-linked authors published space elevator papers in 2000 and 2005. The 2005 paper identifies the tether material as the most critical technology. The 2000 paper concludes the concept may be possible in the latter part of the 21st century if key issues are addressed. [1][2]

  2. In progress · 2025Tether material with the required strength demonstrated

    The 2005 NASA review sets the target as ultra high strength carbon nanotube reinforced composites for ribbon construction, in the 100 GPa range. A 2025 review in ACS Central Science reports carbon-nanotube fibres drawn to tensile strengths up to 4.6 GPa, and says that consistent quality and scalability remain a significant obstacle. The 2022 IAC paper says the longest carbon nanotube made is 0.5 metre, and that tether-quality material still needs more development. Research on the material is active, but the target has not been reached in a tether-grade composite. [2][5][4]

  3. Not startedTether-grade material produced at kilometre lengths

    No reviewed source shows tether-grade carbon nanotube or graphene material produced at kilometre lengths. The 2022 IAC paper says graphene can be manufactured at two metres per minute and in lengths of up to one kilometre, and gives its tensile strength as similar to carbon nanotubes (130 GPa). The paper does not show that this material is tether-grade, and it says tether-quality material still needs more development. A section heading in the 2025 ACS review names 10,000-metre fibres as a goal, but the review does not report a fibre of that length. [4][5]

  4. In progress · 2012Construction route for the tether chosen

    Hein's 2012 IAC preliminary assessment argues that in-situ construction of the tether from material on a near-Earth object is probably the most promising route, unless a much stronger tether material is found. The assessment is a preliminary study, not a demonstration. [3]

  5. Done · 2009Power-beamed climber run on a one-kilometre cable

    NASA's Power Beaming Challenge in 2009 required robots to climb a suspended cable one kilometre long at a minimum speed of two metres per second. The robots ran on light aimed at photovoltaic cells on the climber. NASA Spinoff reports that LaserMotive was the only team to win prize money. The cable was held aloft for the attempts, so this was a ground test rather than an orbital tether, and it does not show a climber for an Earth-to-orbit elevator. [7]

  6. In progress · 2026Climber power options compared in system analysis

    The International Space Elevator Consortium's 2026 study compares laser power beaming, microwave power beaming, solar-powered climbers and an electrically energised tether for a conceptual reference climber. The page does not mention hardware tests or a funded programme. [6]

  7. Not startedFull-length tether tested in orbit

    No reviewed source shows a full-length tether, or a climber running on a cable, built or tested in space.

  8. Not startedGround anchor and Earth-to-orbit cable built

    No reviewed source shows the ground anchor, the cable deployment or the orbital counterweight built or tested at scale.

  9. Not startedOperational elevator carrying cargo to orbit

    No reviewed source shows an operating space elevator. A working system would need the tether, climbers, anchor and orbital counterweight to be built, tested and run together.

Why it matters

A working space elevator would offer a different way to move mass to orbit that does not rely on rocket launches. Whether it can be built depends almost entirely on whether a material strong and light enough for a tether long enough to reach orbit can be made in quantity. The concept has been studied since at least 2000, but the material gap has not closed, so the concept remains a long-term option rather than a near-term project.

What stands in the way

  • Tether material: NASA's 2005 review names ultra high strength carbon nanotube composites as the most critical technology, and no tether-grade material has been shown.
  • Length: the 2022 IAC paper gives 0.5 metre as the longest carbon nanotube made, and the 2025 ACS review reports individual nanotubes up to 550 millimetres. Both are far short of the length a tether needs.
  • Manufacturing: the 2022 IAC paper says tether-quality material still needs more development, and the 2025 ACS review says consistent quality and scalability remain a significant obstacle.
  • Fibre to composite: the 2025 ACS review says the effects of space radiation on fibre stability still need study. No reviewed source reports short fibres joined into a long composite tether, or its creep, fatigue or damage-tolerance behaviour.
  • Construction route: Hein's 2012 preliminary assessment says in-situ construction is probably the most promising route unless a much stronger tether material is found, and no reviewed source shows that route tested.
  • Climber power: the 2026 ISEC study compares power options for a conceptual climber, and its page does not mention hardware tests. No reviewed source shows a climber powered at orbital-tether scale.
  • Anchor, cable deployment and orbital counterweight: no reviewed source shows these built or tested at scale.

Published forecasts

What others have predicted. These are their estimates, not ours.

WhoForecastTimeframeMade
David V. Smitherman, Jr. and Joe T. Howell (NASA Marshall Space Flight Center)The space elevator concept may well be possible in the latter part of the 21st century if proper planning and technology development is emphasised to resolve key issues. The year range is an interpretation of 'latter part of the 21st century'. [1]2050–2100Jan 2000

Signals to watch

  • A peer-reviewed paper or independently checked result reports carbon nanotube or graphene material with tether-grade strength at kilometre lengths.
  • A tether-scale test segment is deployed in orbit or on the ground, with results published.
  • Peer-reviewed papers report nanotube or graphene lengths well beyond the 0.5 metre figure in the 2022 IAC paper.
  • A climber demonstrates sustained traction on a representative tether without damaging it.
  • A near-Earth object mission returns material that is tested for tether production.
  • An independent economic analysis compares delivered cost per kilogram at the same destination with rockets and other transport concepts.

Sources

  1. conference paper
    Space Elevators: Building a Permanent Bridge for Space Exploration and Economic Development
    David V. Smitherman, Jr., Joe T. Howell. American Institute of Aeronautics and Astronautics (AIAA Paper 2000-5294), NASA NTRS, Jan 2000.
  2. conference paper
    Critical Technologies for the Development of Future Space Elevator Systems
    David V. Smitherman, Jr.. NASA Marshall Space Flight Center (IAC-05-D4.2.04), NASA NTRS, 2005.
  3. conference paper
    Producing a Space Elevator Tether using a NEO: A Preliminary Assessment
    Andreas Hein. International Astronautical Federation, IAC archive (IAC-12,D4,3,10,x14738), 2012.
  4. conference paper
    Space Elevator tether materials: An overview of the current candidates
    Adrian Nixon, Dennis Wright, John Knapman. International Astronautical Federation, IAC 2022 (paper 69339), 2022.
  5. review article
    Advancing Carbon Nanotube Fibers: Addressing Challenges from Production to Application
    Hao Guo, Chunlei Dong, Qingquan Han et al.. ACS Central Science, 11(6), 855-867, 3 Jun 2025.
  6. other
    Powering the Space Elevator
    International Space Elevator Consortium (ISEC), 2026 study, 2026.
  7. other
    Lasers Enable Alternative Power Transmission
    NASA Spinoff 2016, 2016.

Last reviewed 21 Oct 2026.