Over the last year or two there have been renewed discussions about a return to the Moon, and even having a permanently-manned base there. This is certainly technically feasible. However, the big question is why might we want one? The idea of it being a 21st century frontier outpost has a romantic ring to it, but what else could this base do for us?
One vision that has been around ever since we started thinking about space travel is that a moon base would be the jumping off point for space exploration. At the moment space missions start at the surface of the Earth, which makes things extra difficult. Firstly we have the Earth’s gravity to fight. Then on top of that we have the atmosphere to deal with. Travelling through it at supersonic speeds means we have to fight air drag as well as gravity. We need streamlined shells and casings, which add to the weight. Because of weight and drag considerations we cannot make these casings too large, so many spacecraft have to fold up into small spaces. Space missions have been degraded or have failed completely because solar panels, antennas or instruments failed to unfold properly. The Earth’s gravity and the additional weight to be carried make launchers large and launches violent. In the few minutes needed to get into space astronauts and equipment get a savage shaking.
Launching from the Moon would be a lot easier. The gravity is only a sixth as strong as Earth’s and there is no atmosphere. Without atmospheric drag spacecraft need no streamlining or additional casings, and with no wind to blow them off, the panels, antennas and instrument booms can be already deployed and tested before launch.
On the Moon almost the whole electromagnetic spectrum would be available for astronomy, and the vacuum environment would make many physics research instruments easier to make and operate.
The Apollo astronauts demonstrated that people can work on the surface of the Moon for hours at a time. However, they did not live there. Lunar settlers would need a lot more room, privacy, amenities, and a shirtsleeve environment.
One disadvantage of space stations is that apart from abundantly available solar energy, everything else: air, water, food and other materials all have to be either lifted from the surface of the Earth, or possibly brought 400,000 km from the Moon. The Moon receives abundant solar energy too, and there is evidence that water and oxygen can be obtained from lunar rocks. Many raw materials could be mined locally.
A downside of living on the Moon is that there is no atmosphere or magnetic field to screen out harmful solar and cosmic radiation, and there are savage daily temperature variations. Fortunately, these problems can be mitigated by living ten metres or so underground. Many Canadian cities have adopted this solution to avoid our challenging climate, so we should find dealing with the Moon base issue not that unusual. There are lots of challenges, and it won’t happen for a few years yet, but there will be a moon base one day.
Jupiter and Venus continue to dominate the southwestern sky in the evenings. Mars rises around 8 p.m, Saturn at 11 p.m. The Moon will be New on the 21st.
Ken Tapping is an astronomer with the National Research Council’s Herzberg Institute of Astrophysics, and is based at the Dominion Radio Astrophysical Observatory, Penticton.