July 31, 2178.
Planning ahead FTW!

Since Space Pirates Episode I seemed to be well received by the four people who read it, I feel a little more comfortable discussing it in this space. If it pleases the readership of this blog, I may post a few articles with "behind the scenes" information from time to time.

NB: this post contains very minor spoilers. If you have not yet read SPE1, and intend to do so, you may or may not wish to skip this post.

In case you hadn't figured it out, that date is the date that Space Pirates begins on. While it may have been difficult to figure out, a very observant reader, making a few educated guesses, probably could have guessed it, along with a few other possibilities. Allow me to go through the clues, and explain why I chose that date in particular.

When I was first looking for a time frame in which to set SP, I had to balance a few things out. I didn't want the technology to feel outlandishly advanced, so it couldn't be so far into the future that you would expect everyone to carry personal laser guns, ships to travel through hyperspace, or people to move ship-to-shore with transporter beams. On the other hand, it had to be far enough into the future that mankind had colonized much of the solar system, and it was believable that there were cities with millions of people on them.

I figured 200 years into the future might be the right balance point to accommodate, but I didn't want it to be exactly 200 years. I wanted to err on this side of that mark, making it a little less than that. So I decided it should take place 200 years after my birth year, or 2180.

Using Celestia, here's a picture of what the relevant part of the solar system will look like 200 years after the moment of my birth.



This gave me a starting point, and allowed me to create a picture of Arcas station in the story. You might remember, towards the beginning of Chapter 2, when Jack is flying Redemptrix on approach to Arcas, the mention that Jupiter was "beginning its close approach to Saturn", and that it was closer than it had been for 60 years, and as such, the harbor was busy, since it was a convenient stop-over for ships heading to Saturn from the inner solar system. This paragraph originally noted that Jupiter was just past its close approach, and traffic was tapering off, but it could still be used as a stopping point on ships inbound from Saturn.

(This is also your clue to the year. The prologue begins "it is the second half of the twenty-second century", and the 60-year close approach of Jupiter and Saturn takes place in 2179.)

As I continued the story, I needed a place for the crew to head to for repairs, after they were damaged in the pirate attack. (The original plot had them heading for the planet that the fluyt was en route to, because the original plot involved faster-than-light travel, and they weren't even in our solar system. It wasn't until I was half-way into chapter 1 that I stripped out that technology, and had to come up with new locales for everything.) After some browsing on Wikipedia, I decided Ceres would be a good location to have them visit. It was an interesting, if little known, part of the solar system, and was in the asteroid belt, which I had already decided the pirate attack would take place in.

The only problem, is that in 2180, Ceres is about as far as possible from Jupiter.


The red cirlce marks Ceres' orbit, and the red diamond, Ceres herself.

I had already decided that the site of the pirate attack would be relatively close to Jupiter, envisioning it in about a straight line between Jupiter and the Sun. This was because I wanted the shortest possible travel time between Callisto and the fluyt, because I knew the crew would make this trip three times over the course of the story, which was supposed to take weeks, not months. I had referenced that during normal space flight, ships would accelerate at 9.8m/s/s (about the acceleration of Earth's gravity) for about 8.5 hours, which puts them at a speed of about 300k/s (or o.1% of the speed of light). This means in the twelve days mentioned at the start of chapter 4 that it took them to travel from Callisto to the site of the pirate attack, they would have travelled a little over 300,000,000 kilometers, or a little under the difference between Jupiter's semi-major axis and Ceres semi-major axis. In 2180, this would be no where near Ceres.

(Part of the reason I picked that travel speed, is because the "feel" of SP was supposed to be a combination of the 18th and 22nd centuries: travel times needed to take weeks, if not months, like a sailing ship might when sailing from Europe to the New World, but the whole solar system needed to feel within reach, and not at the years' reach that most of it is for us now. (I mean, how long is it going to take the New Horizon's probe to reach Pluto? (Nested parenthesis FTW!)))

The obvious solution was to just back up time a little bit. Ceres has a 4 1/2 Earth-year orbital period, so backing up two years, to 2178, made sense.

So this is what the solar system will look like on my 198th birthday.



Not bad, not bad. At least Ceres is on the correct side of the Sun, relative to Jupiter. But it had to make sense that they would head to Ceres, and not somewhere else. I didn't want them going to Earth, because this is supposed to be a tale of life off our homeplanet. Mars would be another logical place, being particularly close, but I didn't want them going there, because it figures prominently in Episode II, and I didn't want to be re-treading the same ground. In this view, even Venus might make a better repair stop. Basically, I had to pick a time where it would make the most sense to head to Ceres for repairs, instead of another well-known location. My solution to that was to find a time when those planets were retrograde from Redemptrix' position after the pirate attack (which you can imagine as being a few degrees counterclockwise from the line from Jupiter to the Sun).

(A note on retrograde travel: if you told a NASA scientist that you wanted to travel in a retrograde orbit, he would probably laugh at you. The Earth is traveling at almost 30k/s in its orbit around the Sun, in a counterclockwise direction (as seen from the Sun's north pole). To counter this, and try to fly clockwise around the Sun, would mean you would have to completely counter that velocity, and expend extraordinary amounts of fuel. Far more than any rocket could practically carry into orbit. It's for this reason that when we launch rockets, we always launch them east (in the direction of the Earth's rotation, to take advantage of that velocity) and rockets that leave Earth's orbit always travel counterclockwise around the sun. However, here I had established technology that allows ships to travel approximately three times faster than the Earth in her orbit about the sun. Countering this momentum would be trivial. This is part of the reason why Redemtrix had to be damaged to the point where she could hardly accelerate. It made any retrograde object unreachable.)

Backing time up a few month, we see that, conveniently and coincidentally, all three likely inner solar system planets become retrograde from Jupiter, with Venus crossing the line towards the end of October.



But in the proluge, I had mentioned that not all colonies were on planets, and that some cities were just space stations. I thought it likely that there might be colonies in a Lagrangian point, as there has already been a society advocating just this. This meant backing up time further, to when the L4 points, which precedes an object in its orbit by 60 degrees, for Mars, Earth, and Venus were also retrograde.

It's difficult to eyeball, but Venus' L4 becomes retrograde relative to Jupiter around mid-September.



You can see in this picture, that both Earth and Mars L3 points are not retrograde, but are more than 90 degrees around the sun, making them impractical. Zack mentions that Earth's L3 is 6 to 8 weeks away.

Of course, there is always the possibility of there being some other station close by. I attempted to hand wave (careful with that link; it will suck hours of your life) why they wouldn't head to one by having Zack mention "Granger outpost", a heliocentric station (implying it orbits the sun directly, and is not associated with any other body), and having Jack make a vague mention that it would be "unwise" to head there, as if they had a history with the place.

Now, there was one more thing to take into account to find the date, and that was the mention, again in chapter 2, that it was "close to midnight in Callisto's four hundred hour-long day." I also established that Arcas (link for those that didn't get the reference) station was about directly opposite Jupiter on Callisto. This made sense to me, because if it was primarily used as an interplanetary harbor, it would make sense to build it where you could take most advantage of Callisto's orbital momentum, on the outermost edge of its orbit, where you would be traveling the fastest. So midnight Arcas time would mean that Callisto was in opposition to the Sun, from the perspective of Jupiter.

Callisto orbits Jupiter once every 400 hours, or just over 16.6 Earth-days, so stepping backwards from mid-September, from opposition to opposition of Callisto from Jupiter, that would mean that chapter 2 begins on either September 14th, August 28th, or August 11th. I chose August 11th for now obsolete reasons (it had to do with Regina's birthday, which I removed as a plot point from the story).

Here's the Jupiter system on August 11th.



You can sort of tell by the bright side of Jupiter that Callisto is opposite from it.

Here's the same view date, as viewed from Callisto.



Conjunction occurs just after 7:30pm, UTC. (Hence the reference that it was close to midnight; I figured they landed around noon UTC.)

Twelve days after August 11th, is August 23rd. This is what the solar system looks like then, the day of the pirate attack and all those shennanigans.



Ceres is very clearly closest to Jupiter when compared with the inner solar system planets, and even more convenient than their Lagrangian points. You could probably figure out their exact position by using the reference that they were 30 million miles from (48 million km) from Ceres. Presumably there is a circle in space that is 311 million km from Jupiter and 48 million from Ceres. Or I did the math wrong. (A quick math check shows the latter. On August 23rd, Jupiter and Ceres are 474 million km apart, so there's a missing 100 million km somewhere in there. Oh well, that's what revisions are for.)

From here, you can construct the rest of the timeline of the story:
July 31st: Chapter 1
August 11th: Chapters 2 and 3
August 23rd: Chapters 4 and 5
September 6th*: Chapters 6, 7, and 8
September 7th: Chapters 9 and 10
September 22nd: End of chapter 10

*[minor spoiler warning]When Tim Sikorsky captures Jack and his crew, Tim asked Jack what he was doing. Jack replied "Oh, we just thought we'd go out for a Sunday drive. Get a little fresh air." September 6th, 2178 is, in fact, a Sunday. This is completely coincidental, as I had written that line long before I checked what day of the week, or even knew the date, that it took place on. After I worked out the exact timeline, it turned out that it was a Sunday.