TRINITY: tensegrity Mars Cycler Space Station ustilising resources from Asteroid 25143Itokawa
The TRINITY Mars Cycler is a concept for a space station designed to operate in a permanent orbit between Earth and Mars. A triangular rotating constellation of ultralight inflatable habitats provides artificial gravity. These inflatable habitat pods are protected by a thick layer of regolith filled into bags.
The regolith is sourced from the asteroid 25 143 Itokawa, which already is in an orbit, that is nearly identical to the required S1L1 Mars Cycler orbit. Mirror membranes reflect the visible frequencies of natural sunlight into integrated greenhouses for self-sufficient production of food and oxygen.
It is technically possible to send humans to Mars in 7 months, but key challenges remain unresolved—particularly protection against cosmic radiation and the health effects of microgravity. On a Mars round trip, astronauts would receive up to four times the radiation dose experienced by long-duration ISS astronauts, and microgravity could severely weaken their bodies, risking mission failure upon arrival.
Effective radiation shielding would require thick layers of water or regolith, making conventional spacecraft like SpaceX’s Starship too heavy. Rotating space habitats could simulate gravity, but need a radius of at least 100 meters to avoid motion sickness and Coriolis effects.
A promising alternative is the Mars Cycler—a spacecraft in a stable orbit that regularly passes Earth and Mars. It can house heavy infrastructure, including radiation shielding and rotating modules for artificial gravity, as well as greenhouses for food and oxygen production. Astronauts would use small shuttles to rendezvous with the cycler near Earth and depart near Mars.
the problem with current Mars-cycler concepts and the solution with using the resources from Asteroid 25143 Itokawa
The challenge with previous cycler concepts is the enormous energy required to transport all building materials into Low Earth Orbit (LEO) to assemble the cycler-station and accelerate it into the correct orbit. Providing sufficient shielding from CGR additionally significantly adds to the required material.
Our solution is a tensegrity structure of ultralight prefabricated inflatable modules connected by tethers using centrifugal force as a structural element. These lightweight inflatable modules will be transported to an asteroid, that already has an orbit very close to the optimal cycler orbit and periodically approaches Earth’s orbit. These prefabricated components are assembled on the asteroid into the complete station.
Regolith, an abundant resource on the asteroid, is packed into membrane bags and covers critical infrastructure and habitations pods. It is used for radiation shielding, micrometeoroid protection, and structural ballast.
A candidate object is asteroid (25143) Itokawa which: periodically approaches Earth orbit, contains regolith usable as shielding, and has a low escape velocity facilitating construction operations. This approach significantly reduces required launch mass and propulsion energy.Since the regolith cover also protects from micrometeorids and space debris, the membrane structure can be much simpler and lighter than that of theinflatable module on the ISS, which needs to withstand such impacts.
The complete cycler space station will have a high mass but only minor additional Δvwill be required to bring it from the nearly optimal asteroids orbit into the optimal cycler orbit.
the Trinity Mars Cycler orbit for assembly and when operational
How components work on the Trinity Mars-Cylcler
Three inflatable passenger-pods are protected externally from cosmic radiation and meteorite impacts by bags filled with regolith, which are retained by a load-bearing rope-net structure. Rope-net tunnels connect the passenger-pods to each other and to a central truss column arranged in a double-tetrahedron formation. While the passenger-pods are shielded with regolith, the rope nets offer minimal surface for meteorite impacts and are designed redundantly. They function as a whole, even if some of the ropes sustain damage.
Inside the lower three rope-net tunnels, elevator cabins travel freely and dock at each of the two terminal stations. The advantage here is that a closed elevator shaft, which would need to be under atmospheric pressure, is not required; such a shaft would increase construction mass and be vulnerable to micrometeorite impacts.
In the other rope-net tunnels, counterweights move to continuously adjust the center of gravity of the entire space station, keeping it aligned with the rotational axis.
In the other rope-net tunnels, counterweights move to continuously adjust the center of gravity of the entire space station, keeping it aligned with the rotational axis.
At the “upper” end of the truss column, there is a mirror tilted 45° towards both the Sun and the rotational axis of the space station. This mirror reflects sunlight into the interiors of the passenger-pods via smaller secondary mirrors, illuminating greenhouses that utilize natural sunlight for photosynthesis, supporting autonomous, continuous food and oxygen production. The 45° mirror consists of a fast spinning thin foil that, due to its low mass, is held in a perfect plane solely by centrifugal force. The gyroscopic effect maintains the rotating mirror’s 45° angle toward the Sun, regardless of the rotation and position of the cycler space station.
The concept of an inflatable structure protected by a thick layer of regolith and guiding natural sunlight into integrated greenhouses is shared with our other design for a moon habitat, the we previously have elaborated for the European Space Agency ( ESA )
The rotating mirror also reflects sunlight onto photovoltaic panels, which fill the remaining spaces between the smaller secondary mirrors.
At the lower end of the central truss column is a truss structure that does not rotate, making it suitable for docking spacecraft. A flexible magnetic ring connects this to the rotating part of the station. This truss structure includes three docking stations and an elevator at the center, which leads to the enclosed inner space of the central truss column.
The rotating mirror foil is coated with silver as the reflective medium, allowing minimal UV light into the greenhouses, unlike aluminium coating. The light opening in the passenger compartments is kept as small as possible to minimize the entry of galactic particle radiation. Therefore, the secondary mirrors focus sunlight to a point just outside this opening.
The elevator cabin in the docking area is connected to rails on the truss structure, and it rotates when docking with the enclosed space of the central truss column. This is made possible by guiding the elevator cabin within one or more rings that allow it to rotate freely. The rings are fixed within the non-rotating truss structure, while only the cabin forms a friction-locked connection with the rotating station during docking.
Effective shielding against galactic cosmic radiation requires substantial mass, often several meters of regolith or water equivalent depending on particle spectra and mission duration. Regolith-filled membrane bags surrounding habitat modules provide shielding while maintaining low structural mass.
Future of Interplanetary Exploration
The TRINITY concept represents a leap forward in deep space exploration. By shifting the focus from “disposable” transit vehicles to permanent, shielded cycler stations, we can protect our crews and ensure they arrive on Mars in peak physical condition.
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- For more information on the physiological effects of deep space, visit the NASA Human Research Program.