Our Place in Space: The DART Mission

April 5, 2022April 4, 2022 ~ J.S. Pailly ~ 13 Comments

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, D is for…

THE DART MISSION

So far this month, I’ve been telling you about things that I think will happen (or plausibly could happen) at some point in the distant future. But today, I’m going to talk about something that’ll happen in the not-so-distant future. Something that will happen in the very near future, actually. Later this year, in fact! In late September or early October of 2022, a NASA space probe named DART will deliberately crash into an asteroid named Dimorphos.

Dimorphos is a relatively small asteroid orbiting a much larger asteroid named Didymos. Basically, Dimorphos is Didymos’s moon. These two asteroids will be passing fairly close to Earth later this year. Now I want to be 100% clear about this: neither Didymos nor Dimorphos are going to collide with our planet. We are in no danger. But these asteroids will be coming close enough that we could do a little experiment—an experiment to see just how well we could defend our planet from a dangerous, mass-extinction-causing asteroid, should such an asteroid ever come our way.

DART stands for Double Asteroid Redirection Test. As you can see in the highly technical diagram below, the plan is for the DART spacecraft to have a head-on collision with Dimorphos.

This head-on collision should cause Dimorphos to lose some orbital momentum, which should alter Dimorphos’s orbit around Didymos. How different will Dimorphos’s new orbit be? Hard to say. The exact angle of impact… the astroid’s mineral composition… the amount of debris produced by the collision… all of these things may factor into what Dimorphos’s new orbit looks like.

Astronomers can do all the computer simulations they like, but until we throw a real life projectile at a real life asteroid, we won’t really know what will happen. Not with any kind of precision. Ergo, we need to do this experiment.

Looking once more into the distant future, I believe that humanity is going to spread out across space. Large numbers of people will eventually be living on the Moon and Mars, as well as on other planets and moons of our Solar System. But I also believe these humans in the distant future will take good care of the Earth. Among other things, they will know how to defend Earth from incoming asteroids and comets, so that what happened to the dinosaurs never has to happen again. And that capability—the capability to keep Earth safe from killer asteroids and comets—begins with a little NASA experiment scheduled to occur later this year.

Want to Learn More?

Here are a few papers that I’ve been reading about the upcoming DART Mission. This is where I got most of the information for today’s post:

Our Place in Space: Callisto

April 4, 2022April 3, 2022 ~ J.S. Pailly ~ 18 Comments

CALLISTO

The major moons of Jupiter are Io, Europa, Ganymede, and Callisto. In science fiction, Europa and Ganymede seem to get the most attention. Sci-Fi writers often end up putting human colonists (or at least a handful of plucky human scientists) on the surfaces of one or both of these icy moons. But today, I’m going to argue that Callisto would be a far more suitable home for future humans.

First off, and most importantly, there’s the issue of radiation. The space around Jupiter is one of the most dangerous radiation environments in the entire Solar System. As you can see in the highly technical diagram below, the radiation is most intense in the vicinity of Io. The radiation levels get better in the vicinity of Europa and continue to taper off when you reach Ganymede. You’re still soaking up a lot of radiation, though! Callisto’s radiation levels, however, are fairly low. You might even describe the radiation levels on Callisto as “survivable.”

Furthermore, planetary protection laws in the future may mean that both Europa and Ganymede are off limits to human settlers. Scientists today are 99.99% sure that Europa has a vast ocean of liquid water beneath her surface, and (as you know) wherever there’s water, there may also be life. There’s evidence suggesting Ganymede may have a subsurface ocean, too. Europa is often said to be the #1 most likely place where we might find alien life here in the Solar System. While the odds of finding life on Ganymede are considerably lower, the possibility of Ganymedean life shouldn’t be ignored.

There are already international agreements in place regarding extraterrestrial life. Space agencies like NASA, the E.S.A., and others are legally obligated to do everything they can to protect suspected alien biospheres from our Earth germs (and also to protect Earth’s biosphere from any germs we might find in outer space). For obvious reasons, these international agreements haven’t exactly been tested in court, and it’s a little unclear how they would be enforced.

But in a future where human civilization is spreading out across the Solar System, I’d imagine bio-contamination laws would become stronger, not weaker. Europa would almost certainly be declared off-limits to humans, unless it is proven beyond a shadow of a doubt that no aliens currently live there. Ganymede may end up being off-limits, too, for the same reason.

Meanwhile, we have Callisto. Scientists who want to study possible biospheres on Europa and Ganymede could set up a research station on Callisto. From there, they could keep a close eye on the other moons of Jupiter. They could operate remote-controlled probes to explore Europa and Ganymede without risking contamination, or they could go on brief excursions to Europa and Ganymede themselves (taking proper safety precautions, of course). While they’re at it, these scientist could also explore Io. Io is the most volcanically active object in the Solar System. There is virtually no chance that we’ll find life there, but studying Io’s volcanoes would still be interesting.

I’d be remiss if I didn’t mention this: Callisto might have liquid water beneath her surface, too. Not as much liquid water as Ganymede, and nowhere near as much as Europa, but still… it’s possible. Which means there’s a slim possibility that there could be life on Callisto. But in Callisto’s case, it is a very slim possibility. Based on what we currently know about Jupiter’s moons, Callisto still seems like the best place for humans to live. The radiation levels are much lower, the risk of bio-contamination is negligible… Yeah, if I were a science fiction writer, I’d put my human colonists on Callisto.

Want to Learn More?

In 2003, NASA published a plan to send astronauts to Callisto, with the intention of using Callisto as a base of operations to explore the other Jovian moons. Click here to read that plan. Some of the information is out of date, of course, but it’s still got some interesting ideas. Maybe someday, something like this plan could work!

I’d also recommend this article on Planetary Protection Policy, covering some of the rules that are already in place to protect planets and moons where we might find alien life.

P.S.: If I were a science fiction writer…? Wait a minute, I am a science fiction writer! Click here if you want to buy my first book. It’s not set on Callisto, unfortunately, but it’s still a fun story.

Our Place in Space: Breakthrough Starshot

April 2, 2022 ~ J.S. Pailly ~ 16 Comments

BREAKTHROUGH STARSHOT

So it’s several hundred years into the future. Human civilization has spread out across the Solar System. Large numbers of people are living on the Moon and Mars. We even have successful colonies on Venus and Mercury (more on that later this month) and a few smaller settlements on the various moons of the outer Solar System. Does this mean we’re done exploring space? Heck no! There’s still plenty more outer space stuff to explore!

Just as NASA scientists here in the 21st Century send robotic space probes to our neighboring planets, scientists in the future will be keen to send robotic probes out to neighboring star systems. And the model for a robotic mission to another star system already exists. In 2016, venture capitalist Yuri Milner, theoretical physicist Stephen Hawking, and Facebook C.E.O. Mark Zuckerberg announced funding for a new research project called Breakthrough Starshot.

The idea is to build a swarm of teeny-tiny space probes, use high energy laser pulses to accelerate these probes straight out of the Solar System, and then sit back and wait for our probe swarm to transmit data back from another star system. Specifically, Breakthrough Starshot wants to visit Proxima Centauri, the nearest star system to our own. Proxima Centauri is known to have at least one planet, an Earth-sized world known as Proxima b.

Get it? Because the C.E.O. of Facebook is involved in this project!

Could we actually build space probes that small? Well, computer chips are pretty gosh darn small at this point, and they keep getting smaller. So do cameras and other advanced electronic devices. So yeah, this part of Breakthrough Starshot’s plan seems plausible enough.

What about that whole high energy laser pulse thing? That part does seem more speculative to me, but experiments in Earth orbit have shown that light sail technology does work. Just as the sail on a sailboat catches the wind, a light sail can catch light and use that light-pressure to propel a spacecraft through space. A high energy laser aimed at a light-sail-equipped space probe… yeah, that sounds plausible to me, too.

Of course, a lot could go wrong with a space probe traveling through interstellar space. That’s why we’d send a swarm of these things, rather than just one. Most of the probes probably won’t make it to Proxima b, but the few that do survive the trip will send us some spectacular images and data.

Personally, I don’t like seeing headlines predicting that Breakthrough Starshot will be launching by such and such date (typically, a date in the late 2020’s or early 2030’s). Breakthrough Starshot does seem to be founded on good science. It’s the kind of program that really could work, someday. But is it going to happen in the next ten to fifteen years? No, I don’t think so. That seems overoptimistic, in my opinion.

In the more distant future, however, Breakthrough Starshot (or a program very much like it) absolutely could happen. This sort of thing could definitely work. And looking ever further into the future, to a time when humans have thoroughly explored our own Solar System, the idea of sending swarms of microchip space probes to neighboring star systems might become routine.

Want to Learn More?

Click here to visit Breakthrough Starshot’s website. They’ve got lots of information and videos explaining how they intend to get to Proxima b.

I’d also recommend clicking here to see a list of challenges that the Breakthrough Starshot team know they will need to overcome in order to make their plan work.

And for those of you who are looking for some heavier reading, click here to read “A Roadmap to Interstellar Flight,” a scientific paper that essentially serves as Breakthrough Starshot’s founding document.

Our Place in Space: The Aldrin Cycler

April 1, 2022March 31, 2022 ~ J.S. Pailly ~ 23 Comments

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.

I was going to have the Aldrin cycler make a “choo-choo” sound, like I train, but then I realized that would be silly. Things don’t make sounds in outer space.

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.