3D-printed rockets

Coming soon to a launch-pad near you:


SpaceX and others have been printing some parts for years, but it’s about time someone tried to print as many parts as possible. We’ll need that kind of tech once we get out into space.

Thought for the day: Disaster In Space

One of the things that really bugs me in SF are stories where trained astronauts do really stupid things, or act like wet blankets when something bad happens. I’ve you’ve read anything about astronaut training, or any of their biographies, you know that’s just not going to happen. They’re always expecting the worst to happen, and have a procedure for dealing with it… if not, they’ll try things until they fix it or die, they won’t just stand there screaming.

Let’s (not) go to Mars

I remember when going to Mars seemed exciting.

When I was a kid, we read books and watched TV shows about a Mars with canals and bikini-clad princesses, or Martians who wanted to invade the Earth in tripods or by controlling cloned humans.

But, even by then, science already knew that most of those stories were false. The earliest Martian flybys told us that the planet was too cold and the atmosphere too thin to support life much beyond primitive plants. Then, not long after, the Viking landers closed even that loophole when they showed the surface to be an arid desert.

Yet, much of the spaceflight community is still following the old script, first humans land on the Moon, then on Mars. The script made sense when those bikini-clad princesses needed to be rescued from Martian tripods, but not now Mars is just a rock. Any useful resources there are likely to be retrieved more easily from asteroids and moons with much lower gravity where you can use propulsion more efficient than chemical rockets.

It just makes no sense as anything other than an Apollo-style flag-waving exercise. We’d do far better to begin by colonising asteroids whose materials can be used to build more optimal habitats in free space.

Low gravity transport

Here’s an interesting way to simulate Mars gravity:


I’ve been puzzling over this myself recently as I try to finish my first SF novel; it’s set on Vesta, where gravity is approximately 4% of that on Earth. That’s enough to be annoying but not enough to be useful.

Walking relies on gravity, leaning forward to move your legs, so on very low gravity worlds it would be problematic. A bounding run should work, but could be difficult to control.

Wheels would work, but can only put as much power down as the friction between wheel and ground allows. Since the gravity is much lower, the friction will also be much lower, so you won’t be able to accelerate or brake rapidly.

A railway — probably a monorail — seems potentially effective; if the wheels are forced against the rail, there should be enough grip to allow rapid acceleration and deceleration.

Hovercraft seem sensible, since little power would be required to counteract the low weight of the vehicle, and then it can be propelled by ducted fans or similar as though it was in microgravity in free space.

Moving walkways could work, and would likely be a sensible approach for speeds between slow walk and bounding run. If friction between feet and walkway isn’t enough, a railing could pass the force through, even if it would probably be uncomfortable.

More high-tech, some kind of nano-assisted material for soles and tires could help them cling to the ground and at least help with the friction problems.

I’m still trying to think of a sensible solution for movement on these kind of worlds which doesn’t come with a large number of downsides.


Interesting documentary about Skylon:


However, I think it underestimates the fundamental problem with Skylon. It’s very clever, but suffers from what you might call ‘Apollo Syndrome’; it’s very much an all or nothing design which needs huge up-front investment with no guarantee of success. Without that multi-billion dollar investment you have nothing of use, which effectively limits it to a government program as few companies can afford to take that kind of risk.

SpaceX, for example, expects to reduce launch costs to Skylon levels when they have a fully-reusable Falcon, but they don’t need to invest vast amounts of money to do because they can make money from the expendable Falcon first and work toward the low-cost reusable design. The best suggestion I’ve seen for Skylon is to use it as a hypersonic airliner, but that still requires doing most of the work and there’s no proven market.

So will it ever fly? I’d like to think so, but I honestly can’t see how they’ll convince the people who have enough money to give it to them.

Neil Armstrong

Neil Armstrong died, but by now you probably know.

As I said elsewhere, the sad part is not just that the first man to walk on the moon has died, but before long we may be in a world where no man alive has walked on the moon. What a huge step backward for the human race.