Students “clamber” to the stars

A lift into space? Students of the TU Munich are conducting research into such a space lift. They regularly take part in competitions with their “Climber”.

By Bernd Lorenz


Simon Calvini and his team have not let themselves be discouraged by setbacks while developing their ‘space elevator’. 


When recruiting specialists, the lift sector faces strong competition. For Simon Calvini and his team, this is his fellow students from the rocket project. “When we go looking for new members for the Scientific Work Group for Rocket Technology and Astronautics (“WARR”), students are more drawn to two-stage rockets than our model of the space elevator,” the 24-year old noted with regret.

He is studying mechanical engineering at the Technical University Munich (TUM). In his free time, the young native of South Tyrol is in charge of a research group. As part of the “Graksler” (Bavarian dialect for “clamber”) project, they are building a “climber”. “Simply put, this is an electric vehicle that travels along a cable – ideally, one day from the earth’s surface to geostationary orbit.”

However, the slender vehicle does not resemble a lift. At a length of about 150 cm, the Climber 4.3 looks more like an extended USB stick. Thanks to its lightweight carbon design, two students can easily hold it. “We’re currently working on a kind of demonstrator with which we want to transport a working load over the longest distance possible and identify technical problems,” revealed Simon Calvini.

Climber design


CNC-milled components, with the side plates on which the carbon tube frame is attached in the foreground. The wheel axle is guided through the central elongated hole. Photo: © WARR

The aluminium wheels have a radius of about 80 mm. The students have applied rubber to their contact surface, which creates more grip on the rope for the wheels to run. At the moment, the wheels are blocked with e-bike disc brakes. “The brakes are one of the critical points: the most expensive and fragile elements in a space elevator would probably be the rope. This is why it has to be treated as gently as possible. But we also need brakes that could be operated in outer space without electricity.” Calvini is thinking here for example of using active low brakes, which would even work in the event of a power failure.

The climber is currently driven by an electric motor. Calvini would like a design without transmission “because that reduces the weight”. Batteries supply the motor with energy. At full load, they would last just under half-an-hour. “Of course, that’s not an option for a space elevator,” the 24-year old admitted. As a supplement to a more efficient battery, solar panels could be installed which would transform the power of the sun into electricity. The deployment of so-called “power beaming” by contrast still belongs to the realm of fantasy. “This involves directing electricity produced on earth via laser onto solar modules, which is as a result quasi ‘beamed’ into space,” he said to explain the procedure in simple terms.

In principle, transporting someone into space with a lift is possible but it wouldn’t be much fun. On the one hand, there is the length of the journey. Simon Calvini has calculated that at a speed of 15 m/s and a distance of 36,000 km, the journey would take about 30 days. Moving through the radiation belt of the earth would also be problematic. This contained a great many energetic particles that could be harmful to humans. “This is why we’re concentrating more on transporting goods,” explained the head of the climber project. This included raw material, which could be transported more affordably than with rockets and used for the construction of space probes.

Everything depends on a rope


Whether there will ever be a space elevator literally depends on a rope. On earth, the challenges already begin with its form. Up to now, the ‘clamberer’ team has used truck ratchet straps for the climber. “A flat strap transfers the weight better because the wheels have more surface contact. But it’s very susceptible to gusts of wind, which has often led to the rope being blown out between the wheel and the mating gear,” Simon Calvini conceded.

The disadvantages apparently predominated since the young researchers intend in future to experiment with round composite rope. Normally, they test the climber on a belt that is suspended ten metres horizontally or slightly diagonally. To reach the vertical, they need a mobile crane or helium balloon. “Both are of course very expensive.”

Lifting tackle suitable for the space elevator is currently ruled out by its own deadweight. Even with a diameter of a millimetre, a 36,000 km long steel rope would be far too heavy. Graphite or nanotubes made out of carbon were “interesting materials” in Simon Calvini’s view. The latter had the advantage that they were good at conducting electricity. “Unfortunately, they can currently only be produced at a length of about 10 cm.”

Sponsor Schmitt + Sohn


Final preparations and integration of electronics on the Graksler 4.3 in Japan Photo: © WARR

The students are dependent on sponsors’ support for their work on the space elevator. These include the Maker Space in Garching of the lift builder Schmitt + Sohn, in whose workshop thy can make use of many production technologies free of charge. “We had our first sponsoring pitch in the branch in Munich-Unterschleißheim. But then we were also invited to the headquarters in Nuremberg.”

Apart from the great interest in the work of the climber team, Simon Calvini is also gratified by the financial commitment and provision of production capacities. Schmitt + Sohn produced parts for us at short notice for the competition in Japan.” To further expedite their research, the team is on the lookout for sponsors with a five-axis CNC machine and expertise in 3D printing of metal and battery technology.

International competitions 


The Graksler 4.3 without covers – the carbon structure in truss construction is visible. This design was chosen because of its simple assembly, efficient production, low mass and good predictability. Photo: © WARR

Students from other countries are also at work on a space elevator. They regularly meet each other at competitions such as the European Space Elevator Challenge (EUSPEC) in Munich or the Japan Space Elevator Challenge (JSPEC) in Fuji. “The space elevator is a very big affair in Japan in particular.” There were about 15 teams there of which most were even supported by a professor. After the withdrawal of the Technical University Dresden, the approximately 20 “clamberers” were the only ones in Europe, as far as he knew.

The Munich group faced problems at the Space Elevator Competition at the end of 2024 in Japan. “For half of our about 30-minute slot we were just busy trying to attach the climber to the rope,” explained Simon Calvini. On top of this, one of the sensors failed. “As a result, we couldn’t travel autonomously but instead had to steer the climber manually.” During their best attempt, they were able to cover a distance of 50 m. A maximum distance of 200 m would have been possible.

Improvement of the climber


The TUM students use the findings from the competitions to improve the climber. A new feature of the 5.0 version will definitely be a different arrangement of the wheels to allow the rope to be “threaded” more easily. Simon Calvini thinks the Munich space elevator team is technologically well-positioned in terms of electronics, autonomous travel and software. What needs to be improved is the housing. Instead of carbon, he would like to use 3D printed parts made of aluminium, ideally even out of titanium. “Titanium is very light and extremely high-tensile. The ideal material but unfortunately very, very expensive.” Compared to other student groups, he saw the clamberer project “in terms of research relatively close to the top.”

Currently, the team was working on a feasibility study for prototype construction – another important step. However, the young mechanical engineer already knew of a potential starting point for the space elevator. “Geostationary orbit is only possible at the equator. It would be possible there to place a floating island in the Gulf of Guinea below the coast of Guinea.”

But in his view, there would only be a big advance in the development of a space elevator once there had been advances in developing a light, durable rope and in power beaming. It would probably also be challenging for the lift to get through the “cemetery of dead satellites”. “Some of this space garbage colliding with the rope or car would be catastrophic.”

Consequently, a lot of water would probably flow down the Isar before a lift travelled into space. “That’s something I won’t live to see during my WARR time,” smiled Simon Calvini.

More informations: warr.de