The development of resources across the entire solar system requires these new technologies!

Recently, Chinese aerospace experts proposed a roadmap for the development of resources throughout the solar system. In the future, tasks such as the development of water ice resources in extraterrestrial bodies, mining on alien planets, and space flight operations will call for the development and application of more new aerospace technologies to create greater value. Compared with the exploration missions within the solar system in the history of aerospace, what grand goals may be achieved in the development of solar system resources in the future? What new technologies are needed to help? What challenges do researchers need to overcome?

Imaginary picture of ocean probe under the ice layer of alien planet

"Heavenly Creations" layout for large-scale development

Not long ago, the first academic exchange meeting on space science and experiment of the Chinese Society of Astronautics was held in Beijing. At the meeting, Wang Wei, an academician of the Chinese Academy of Sciences, gave a report on "The Development Vision of Space Resource Development System" and launched the "Heavenly Creations" plan initiative.

The report proposes the idea of ​​building a space resource development system from near to far in steps, with the development of strategic mineral resources as the goal, the utilization of extraterrestrial water ice resources as the basis, and the Lagrange points L1/L2 between the two major celestial bodies as nodes.

On the one hand, we will gradually build water ice resource development facilities on the moon, near-Earth asteroids, Mars, main-belt asteroids, and Jupiter's satellites, and step by step build a space resource supply station system involving the moon, Mars, Ceres, Jupiter, etc., and have the ability to explore and develop resources in the entire solar system.

On the other hand, it is planned to build space infrastructure such as space resource supply stations, space resource transportation channels, extraterrestrial mining stations, space resource processing stations, and low-cost return channels for space resources, and gradually form a space resource development system involving the moon, near-Earth small bodies, main-belt asteroids, planets, etc., with the ability to develop and utilize space resources on a large scale and commercially.

In addition, the focus is on the layout of space entry and exit, space transportation, space supply, space mining, and space resource processing technologies, with a focus on breakthroughs in common key technologies such as low-cost resource return, flight-based space resource transportation, space resource supply stations, extraterrestrial mining stations, and space resource processing stations.

In short, the report proposes goals for the "exploration, mining, and utilization" stages, and preliminarily provides a four-stage development roadmap for the development of resources in the entire solar system by 2035, 2050, 2075, and 2100, to promote leapfrog development in the field of space resource development and utilization in my country.

In order to achieve these ambitious goals, it is necessary for aerospace personnel to innovate boldly, develop and apply a series of new technologies.

Exploration, a deeper understanding of the solar system

To develop solar system resources, the first priority is to conduct sufficiently accurate surveys of extraterrestrial bodies.

Existing aerospace exploration methods have made it possible to collect information on the surface resources of extraterrestrial planets, including using probes to reveal the distribution of water ice resources at the lunar poles, very high-resolution imaging of the Martian surface, and using ground-based radar to analyze the main components of the surfaces of near-Earth asteroids.

However, existing technologies cannot provide both detailed and wide-area detection of the surfaces of other planets. For example, the high-resolution camera of the Mars Reconnaissance Orbiter has only scanned and covered about 5% of the surface of Mars in more than 10 years. In the future, in the journey of exploring solar system resources, imaging detection systems with wider width and higher precision will be essential.

Furthermore, the exploration of resources deep inside extraterrestrial bodies is also a new area to be developed. Under the thick ice layer on the surface of satellites of giant planets such as Europa, Enceladus, and Triton, there is likely to be a vast ocean, thanks to the residual heat inside the satellites and the gravitational pull of the giant planets. In the future, these underground oceans may help supply spacecraft performing deep space missions, and even be used to replenish water resources on Earth.

It is not difficult to imagine that surveying these icy satellites requires the use of drills and submersibles to penetrate kilometers of ice by heating and melting ice and travel through the underground ocean. These devices need to rely on radioisotope devices to maintain long-term working conditions and reduce system complexity and overall costs.

In addition, more powerful ground-based and space-based radars will further survey the resource composition of near-Earth asteroids and main-belt asteroids and determine whether they are worth developing.

Considering the long distance and unknown high-risk environment, unmanned probes based on artificial intelligence will become the "pioneers" of exploration, trying to harvest more results at a lower cost and lay the foundation for the establishment of manned deep space outposts. In order to adapt to the harsh extraterrestrial radiation environment, the artificial intelligence computing power and communication capabilities of unmanned probes must be continuously upgraded.

Collection, large-scale access to space

Today, the probe has achieved the return of lunar samples, and the Mars sample return mission is being accelerated. However, compared with the small amount of sampling for scientific research, the total amount of extraterrestrial resources will inevitably increase significantly in the future. To this end, it is necessary for astronauts to master the ability to enter space on a large scale and have a strong enough space transportation capacity.

Heavy rockets and flight-based space transportation vehicles with high comprehensive benefits and reusability should be able to "take the lead". They will use chemical energy to carry out near-Earth orbit launch missions in batches, implement integrated assembly, and build space facilities that are larger and more magnificent than the International Space Station. However, in frequent deep space flights, chemical energy engines have limited specific impulse and low propulsion efficiency, so it is necessary to apply more efficient propulsion technologies based on solar and nuclear energy.

As we all know, the intensity of solar radiation decreases sharply as the spacecraft moves away. Beyond the orbit of Jupiter, the efficiency of solar panels is difficult to meet the mission requirements. In the future, new technologies can be applied to enhance the sunlight focused on the solar panels with the help of reflectors, and in theory, the application of solar panels can be expanded to the orbit of Saturn.

Nuclear-powered spacecraft are likely to be the necessary choice for regular intrasolar system navigation. Due to the low technical maturity of nuclear fission-fragment rocket engines and nuclear fusion propulsion, nuclear thermal propulsion and nuclear electric propulsion seem to be more realistic.

An image of a nuclear-powered rocket carrying out a deep space mission

The principle of nuclear thermal propulsion is to make hydrogen and other working fluids flow directly through the reactor core to heat it and generate thrust. Initial tests were carried out as early as the 1960s. Foreign nuclear thermal rockets with low nuclear fuel concentrations are expected to make their first flight within five years, with the goal of driving spacecraft to reach Jupiter within two years and Saturn within three years.

However, nuclear thermal propulsion currently has some problems, such as long startup/shutdown time. In addition, the reactor core fuel rods may produce abnormal creep, cladding fragmentation, strength reduction and other problems under continuous operation, and multiple startups and continuous working time are limited.

Nuclear propulsion requires the use of complex and sophisticated mechanical structures, active circulation of refrigerants, and a lack of redundant backup, resulting in poor reliability in deep space environments. The working life is often only tens of days, and the huge heat dissipation device will also cause the spacecraft to be "overweight."

In fact, spacecraft must overcome huge challenges to mine resources on the surface of alien planets on a large scale, such as developing more outstanding flexible robotic arms, and they also need to make progress in basic fields such as materials and structural design.

In addition to promoting technological innovation, novel spacecraft design ideas are expected to be put into practice. For example, astronauts can consider using thrusters to "carry" small celestial bodies with sufficient resources closer to the earth, simplify the design of spacecraft landing or sampling, and turn to the control technology of the combination of spacecraft and small celestial bodies.

Utilization, the whole has reached a new level

During the in-depth development stage of solar system resources, the collected space materials will no longer be completely transported back to the Earth, but will be converted into usable resources in orbit as much as possible.

For example, researchers are demonstrating the use of electrolysis of water ice resources on extraterrestrial planets to generate hydrogen, oxygen, etc., to supply spacecraft or space workers; the use of collected raw ores to refine them into metal resources that can be used directly, or even processed into accessories for on-orbit assembly of spacecraft; the use of carbon dioxide and hydrogen on the surface of Mars to generate methane through the Sabatier reaction, and further synthesize organic matter and even food; with the advancement of spacecraft materials and intelligence, we can consider collecting nuclear materials from extraterrestrial planets enriched with radioactive materials to produce reactor fuel rods, or extracting rare gases and electric propulsion fluids from the atmospheres of giant planets.

In short, with the widespread deployment of deep space mission spacecraft and the gradual improvement of space infrastructure, more extraterrestrial resources will be used to support the operation of outposts, and sometimes it is not worth the cost to transport them back to Earth. At present, many countries' aerospace industries have or are about to implement in-situ resource utilization experiments on the moon, Mars and other extraterrestrial planets, which will help explore new models for the development of extraterrestrial resources.

An image of an alien mining scene

Developing in-situ resource utilization on extraterrestrial planets and carrying out space production activities will be the trend of future solar system resource development, and the energy supply problem cannot be ignored. To this end, it is necessary to build space infrastructure such as space solar power stations to help simplify the design of spacecraft and space factories.

Heat dissipation will be another problem faced by space factories: the efficiency of radiation heat dissipation is low, and it is risky to smelt metals at high temperatures on alien planets that lack liquid and atmosphere. In this way, space factories are suitable for being built on celestial bodies such as Mars and Titan that have atmospheres.

Looking into the future, if space factories that produce precision devices become a reality, perhaps astronauts can use the zero-gravity environment to build a "space dock" to assemble some huge spacecraft that are difficult to achieve in the Earth environment, to support longer voyages or transport more cargo.

The aerospace industry has become a "promising field" that countries are competing to invest in, because the nearly unlimited space resources and the technological achievements made in the exploration and development process represent a bright future for national development and strategic competition. With the advancement of technology, the concept of space resource development is gradually becoming a reality, and aerospace workers still need to continue to work hard with continuous investment. (Author: Zhang Chen)