According to media reports on August 14th， a research team from the Institute of Space Systems at the Technical University of Braunschweig in Germany is actively pursuing an ambitious plan aimed at paving the way for long-duration human space travel， with the ultimate goal of achieving Mars exploration.
This team intends to move away from traditional， high-cost， and toxic hydrazine-based fuels， opting instead for a more environmentally friendly and efficient cryogenic fuel approach. The core of this strategy involves the combination of oxygen with either liquid hydrogen or liquefied methane. This shift not only reflects a commitment to sustainability but also signifies a significant innovation in space propulsion technology. This is a crucial step， as current propulsion systems are often limited by fuel toxicity and efficiency， posing challenges for extended missions and astronaut safety. The adoption of cryogenic fuels， while demanding in terms of infrastructure， offers the potential for greater thrust and specific impulse， which are vital for reducing travel times and payload mass.
A particularly noteworthy aspect of their proposal is the forward-thinking concept of producing these cryogenic fuels directly on the Moon. Based on an analysis of lunar soil samples brought back by China’s Chang’e-5 mission， which found approximately 120 grams of water per ton of lunar regolith， the team plans to extract hydrogen and oxygen by decomposing this water. This in-situ resource utilization (ISRU) approach is expected to address a critical aspect of deep space mission logistics: fuel supply. The ability to generate propellant locally eliminates the need to transport all necessary fuel from Earth， dramatically reducing mission costs and complexity. This strategy aligns with the broader push for sustainable space exploration， making long-term presence and operations in space more feasible.
The research team is also envisioning the establishment of fuel storage depots on the lunar surface or in lunar orbit. These “space gas stations” would serve to refuel spacecraft en route to Mars， ensuring the continuity and feasibility of deep space exploration missions. The strategic placement of such refueling infrastructure in lunar orbit offers a distinct advantage by leveraging the Moon’s gravitational well and proximity， potentially making the process more energy-efficient than relying solely on Earth-based launches or interplanetary refueling. This distributed refueling network is a cornerstone for enabling sustained human presence beyond Earth orbit.
However， the team candidly acknowledges the significant technical challenges that lie ahead in realizing this vision. These include the long-term safe storage of cryogenic fuels in the harsh space environment and the reliable ignition of rockets in a microgravity setting. Cryogenic fuels， by their nature， require extremely low temperatures to remain liquid， and maintaining these conditions over extended periods without significant boil-off is a complex engineering feat. Furthermore， the dynamics of fuel behavior and combustion in microgravity present unique hurdles that require innovative solutions to ensure mission success.
Simone Silvestri， a rocket scientist at TU Braunschweig， emphasized that the team’s core research is focused on developing high-thrust， high-specific-impulse propulsion systems， achieving efficient thrust control， and overcoming the key technical challenges of space fuel storage and management. She revealed that the team is currently expediting the construction of a compact combustion testbed specifically designed to explore effective methods for storing and refueling these novel cryogenic fuels in a space environment. This dedicated testbed will be crucial for validating their designs and operational procedures， simulating the conditions of space to gather vital data on fuel behavior and propulsion system performance.
