Hello, friends! Welcome to Our Place in Space: A to Z! For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space. If you don’t know what the A to Z Challenge is, click here to learn more. In today’s post, A is for…
THE ALDRIN CYCLER
Even in the future, space travel will be expensive. True, new technologies should make it less expensive than it is today, but there’s one problem that will never go away, no matter how advanced our technology gets: gravity.
Anywhere you want to go in space, you’re going to have to fight against gravity to get there: Earth’s gravity, the Sun’s gravity, the gravity of other planets and moons—at some point on your journey, you’re going to have to fight against any or all of these gravitational forces. And fighting gravity uses up fuel. Lots and lots and lots of fuel.
And yet, despite the unforgiving and unrelenting force of gravity, human civilization will eventually spread out across the Solar System. I’m not going to tell you it will happen in the next twenty years. I won’t tell you it will happen in the next century, even. But someday, it will happen. I’m sure of it! And so today, I want to talk a little about what the future transportation infrastructure of the Solar System might be like.
American astronaut Buzz Aldrin is, of course, most famous for being the second person to set foot on the Moon. Aldrin is also a highly accomplished scientist and engineer. In 1985, he did some math and discovered a very special orbital trajectory that would make traveling from Earth to Mars (and also from Mars back to Earth) far more fuel efficient.
The term “Aldrin cycler” refers to that very special orbital trajectory Aldrin discovered. The term can also be used to describe a spacecraft traveling along that special orbital trajectory. The initial investment to build an Aldrin cycler (the spacecraft, I mean) would be really high. We’d probably want to build a rather large spacecraft for this, and once it’s built, maneuvering the thing into the proper trajectory would require a stupendous amount of fuel.
However, once we’ve done all that, the cycler will cycle back and forth between Earth and Mars, over and over again, pretty much forever. Traveling to Mars would be a little like catching a train.
Passengers would board the cycler as it flew past Earth; about five months later, they’d disembark and head down to the surface of Mars. The cycler would then take a long journey (about twenty months) looping around the Sun before flying past Earth once more; then the “cycle” would begin again.
The trip from Earth up to the cycler would still require some amount of fuel. So would the trip from the cycler down to the surface of Mars. The cycler itself would also require a little bit of fuel for maneuvering thrusters; otherwise, over time, the ship could start to drift ever so slightly off course.
Obviously this is not a cost-free form of space travel, but I’m sure you can see how this could help keep the cost of space travel down. And so I imagine in the distant future, the Aldrin cycler (or something very much like it) will be a key part of the Solar System’s infrastructure, just as trains are an important part of our modern day infrastructure here on Earth.
Want to Learn More?
Click here to see a short animation of the Aldrin cycler orbital trajectory, showing several cycles worth of Earth-to-Mars and Mars-to-Earth journeys.
I’d also recommend Buzz Aldrin’s book Mission to Mars: My Vision for Space Exploration, where Aldrin describes the Aldrin cycler (and other cool Mars related things) in more detail. Click here to see the book’s listing on Amazon.