China explores using orbiting lasers to power spacecraft on the moon

 China could look to laser power transmission from lunar orbit to supply spacecraft on the moon and solve one of the big challenges for its lunar exploration plans.

 

Researchers have assessed the viability of using laser wireless power transmission (LWPT) from lunar orbiters to supply spacecraft left in the dark during the long, dark nighttimes on the surface of the moon. LWPT uses laser beams to transmit power wirelessly from orbiting satellites to surface receivers, converting light into electricity. The researchers recommend the development of key technologies, followed by on-orbit testing.

The moon being tidally locked to Earth results in extreme environmental conditions, with 14-day-long periods of darkness and extreme temperature fluctuations. While solar power can provide energy for spacecraft during the lunar days, the long nights bring challenges. Spacecraft typically need heat and a level of power to survive complete darkness and temperatures as low as -200 degrees Celsius (-328 degrees Fahrenheit). 

As well as providing power during lunar nighttimes, LWPT could also support spacecraft operations in permanently shadowed craters, thought to hold water-ice, which can be used to make propellant or water or oxygen for astronauts.

Solutions such as radioisotope power sources are limited in power output and costly. Nuclear reactors, meanwhile, are ideal for large-scale bases, but bring concerns in the shape of safety and complexity.

LWPT is thus seen as a solution to some of the energy challenges faced during lunar exploration, offering flexibility and scalability in vacuum conditions, according to a paper published in the Journal of Deep Space Exploration (JDSE) in October 2024. 

However, challenges such as efficiency, transmission ranges, visibility and operational challenges stand in the way of effectively utilizing LWPT.

“It is necessary to focus on the development of space high-power lasers and high-precision laser emission systems, and on-orbit technology verification should be carried out as soon as possible,” the authors conclude.

The paper was produced by authors from institutes including the China Academy of Space Technology (CAST) and Shandong Aerospace Electronics Technology Research Institute. The paper assesses various orbits to determine the optimum solutions for supplying areas such as equatorial regions and the poles.

NASA and the European Space Agency (ESA) have made earlier studies into supplying spacecraft on planetary surfaces using lasers in the 1990s and 2000s.

LWPT could be very useful to China as it expands its lunar exploration ambitions. The country is planning the construction of a moon base, known as the International Lunar Research Station (ILRS). Precursor missions, Chang’e-7 and Chang’e-8, are due to launch in 2026 and 2028 respectively. The multi-spacecraft missions will land at the lunar south pole, assessing the availability of resources and seeking out water-ice in shadowed craters, as well as testing in-situ resource utilization (ISRU) technologies. Last year China completed the first sample return mission from the lunar far side with Chang’e-6.

The ILRS will be constructed in the 2030s using a super heavy-lift launch vehicle to establish power, communications and other infrastructure at the chosen site. “Energy supply will become one of the core technical issues in lunar exploration and lunar resource development and utilization,” the authors of the paper assert. 

Developing systems such as LWPT could provide China with solutions to key challenges to sustainable lunar exploration and provide a level of leadership in this arena.

Meanwhile, China is also researching the possibilities of space-based solar power. That project envisions generating power in geostationary orbit and beaming it to Earth. The country plans to use its Tiangong space station to test key technologies required for space-based polar power. China is also researching challenges of developing kilometer-scale ultra-large spacecraft needed for the project.

 Credit: spacenews.com

Space Solar - the Future of Energy?

Today, there are many drivers for the development of renewable energy sources, with national defense, rampant over-population of the planet, quality of life for future generations, and concern for the environment all near the top of the list. Yet we seem content to burn the fuels we can gather from our surroundings, much like our ancestral cave-dwellers did for tens of thousands of years before “modern” man’s arrival.

There have been substantial efforts to introduce and make wider use of renewable energy, however, according to the International Energy Agency the world's share of renewable energy in 2012 was just 13.2% and according to the U.S. Energy Information Administration, the world's consumption of renewable energy in 2015 dropped to 12.5%. Taking into account that these figures include hydro power, which today makes majority of renewables (but has limited potential for growth) the share of solar energy is estimated at 3% or below.

Sun is the most abundant and unlimited source of energy. With the recent advances in technology and mass production solar approaches, and in some instances have reached parity with the traditional sources. Why don't we use it more widely and eliminate the need for fossil fuels completely? The reason is (and similarly for wind) is in its intermittent and unreliable nature, and their uneven availability across different geographical locations. Previously I have written about the Ascent Mobile Energy System (AMES). The module can be delivered to practically any destination, deployed and produce clean energy in autonomous mode. However, even such an advanced integrated system can be challenged to sustain uninterrupted energy production for extended period of time beyond Arctic Circle or in other locations with extreme environments.

There is a technology however which for a long time has been a subject of science fiction only. It is called Space Solar Power, or SSP. The idea of SSP in theory is simple: harvesting virtually unlimited solar energy with orbiting collectors and beaming it to Earth. Unlike terrestrial solar (or wind), the Space Solar is available any time of the day and year, is not subject to weather conditions or obstacles, and - the most important - has no geographical limitations. 

State of technology and humongous cost of its realization, combined with relatively low fuel prices, for a long time hindered its development. Now the technological gap is closing rapidly, and with the growing energy demand and all the challenges meeting it, the cost can be overcome. It became a subject of intense research in recent years and a number of countries have started testing technology in practice. 

The US, Japan, and Russia have all made investments in this area, and the space departments of Canada, Europe, and South Korea are also conducting related research.
However it is China who is expected to be the world's first country to build a practical solar power station in space according to Li Ming, a research fellow from China Academy of Space Technology.
China entered the top ranks in research of space solar power after decades of research which has significantly narrowed the gap with other leading countries.
China has undertaken the research of space solar power since 2008, with a number of major breakthroughs in wireless energy transmission achieved. According to Wang Li, another research fellow with the CAST, experts from both home and abroad agree about China's leading role in this field. Apart from the technology, the construction of the space solar-power station also needs huge investment, broad market and support from government, all three factors China can deliver, unlike other countries.
Space solar power will ease environmental and energy pressure on China, and also expected to spur the country's innovation and emerging industries.
(Source:  China Daily)