Commercial operations on the Moon won't just be round-the-clock but round-the-calendar as ispace, inc. and the University of Leicester partner to develop nuclear heaters to allow future landers and rovers to survive the freezing lunar night.
There have been a number of robotic lunar landing attempts recently with varying degrees of success. However, they've all had one thing in common: they had a very limited mission lifespan. The problem is that the Moon is subject to extreme swings of temperature from day to night. When the Sun is up, the thermometer rises to 250 °F (121 °C) and at night it plunges to -208 °F (-133 °C).
Daytime isn't too much of a problem because the Moon's surface is a vacuum, so it's relatively easy to control heating with reflective surfaces. Nighttime is another matter. A spacecraft's heat can quickly radiate away and by the time the Sun rises again after two weeks of darkness the lander's batteries and electronics can be damaged beyond saving.
Looking to a future with a permanent human presence on the Moon that includes a lot of commercial activities, ispace and the Leicester's Space Nuclear Power group want to develop nuclear heater units for future missions, beginning with ispace's Series 3 lunar landers and rovers.
These units aren't nuclear reactors, but what are called radiothermal generators (RTG). They don't work by fission, but the natural radioactive decay of enriched nuclear isotopes like plutonium. As they decay, they give off heat, which can be used to generate electricity or to keep a spacecraft from freezing in the lunar night or on deep space missions in the outer solar system and beyond.
Even if the idea of using a RTG to keep a lunar lander or rover alive has been around for half a century, the ispace/Leicester project is a bit different. Not only is this a private venture designed to support private lunar missions, it also uses a different isotope. Where most other space missions have used plutonium-238, the new heater will use americium-241. This is not only cheaper and less controversial, but has a half-life of more than 400 years, so it can keep a rover toasty for many years.
"The radioisotope power technology that has been developed at the University of Leicester, in conjunction with National Nuclear Laboratory, is performing extremely well in our ongoing testing campaigns," said project lead Dr. Hannah Sargeant from the University of Leicester School of Physics and Astronomy and Space Park Leicester. "In this project, we will be working with ispace to investigate the feasibility of using radioisotope heater units to provide sufficient heat to spacecraft to endure the lunar night.
"The first phase of UKSA International Bilateral Funding was used to work with our international partners to understand their power needs and mission priorities. In Phase 2, we will be conducting both laboratory and concept studies to demonstrate the feasibility of the mission concepts. It will also provide an opportunity to highlight the technology to the civil and commercial space industry and show how it could be used to meet critical power needs for priority missions."
Source: ispace
