It’s hard not to simply praise Outer Planets as a worthy expansion of everything Leaving Earth stood for. After all, the original game quickly rose through the ranks of my favorites for its abstraction of difficult spatial and mathematical conundrums, not to mention its absolute delight at the prospect of space exploration. It was as optimistic as it was brainy. So when Outer Planets fleshes out everything that made that first voyage so captivating, does that make it as good as its predecessor?

Absolutely. Or, well, mostly. Maybe ninety percent.

Farther than I’ve ever traveled before.

Before we get into anything else, let’s talk about all the stuff Outer Planets tosses into the mix. Because while it unquestionably introduces a whole lot, the real issue is whether any of it is meaningful.

The most obvious addition is the outer planets themselves. Where Leaving Earth reached only as far as the asteroid belt — more specifically, to Ceres — now the expanse sprawls all the way out to Uranus and Neptune, encompassing the moons of Jupiter and Saturn along the way.

Not that any of them are immediately reachable. As in the original, much of your first decade is spent on raw experimentation or racing for goals within the inner system. Getting a man into space and back, testing rockets so they don’t detonate your entire payload, taking a peek at a few flybys of Mars or Venus. Fortunately, you’re given an extra decade of wiggle room, stretching the timeline to 1986, otherwise you’d barely have the ability to scratch the surface of what the jovian giants have to offer. It’s even difficult to plan ahead thanks to the way these outer planets alter the way goals are set. Rather than start the game with all your tasks laid out before you, then tailoring your entire space program to meet their challenges, you must first survey them, taking advantage of slingshot windows (and probably ion thrusters, which are more important than ever) in order to reveal the late-game missions that dominate the last decade. These follow the usual pattern of getting satellites or probes or manned missions going, so it’s vaguely feasible to start preparing before those surveys are complete. But when thrust and mass are at their premium, it’s not always going to be easy to assemble the right pieces until you have a good picture of what you’ll be trying to accomplish.

To aid these far-reaching missions, Outer Planets provides a small handful of new tools. Proton Rockets are a mid-thrust option that are cheaper than Saturns but punchier than the Soyuz, adding a nice middle-of-the-road option for breaking Earth’s gravity in stages. Heavier Galileo-class probes are resistant to the potential radiation beyond the asteroid belt, while Explorers represent rovers or submarines specially tasked for particular missions. Scientists join up as a fourth class of astronaut, able to analyze planetary samples without returning them to Earth. Which maybe sounds breezy until you remember all those finicky life support systems. A scientist is no good if he’s suffocated.

Most interesting is aerobraking, the ability to skid your ship along an atmosphere like a kid slowing down his skateboard with the bottom of his shoe. Not only does this seriously help with certain maneuvers — and not only is it bonkers dangerous — but it also led to one of my favorite stories in Leaving Earth. My sister-in-law was bound for Saturn, but the launch window was near enough to the game’s conclusion that she didn’t have time to test the technology prior to launch. Instead, she hurled her ship towards Saturn, then spent the next seven years perfecting the technology by skipping rockets across the atmosphere of Venus. Failure after failure taught her the techniques she would need to succeed on her main approach, which saw her scoring a hilarious number of points when she charted the oceans beneath the ice of Enceladus. Science at its most awesome.

The outer planets make the game layout sprawl. In a mostly good way.

More. It’s obvious that Outer Planets adds a whole lot of it. But does it alter the game enough to warrant its inclusion?

For the most part, yes. Increasing the game’s turn length by fifty percent naturally makes it go on a while longer, even to the point of dragging a little. Our first attempt, staffed with veterans of the base game, took nearly five hours. This is especially noticeable because not much is altered in the early stages, when rockets are still lengths of plumbing with some gasoline poured through them and generating enough thrust to throw a baseball into orbit is madness. Those early years are as occupied as ever with the business of testing, testing, and more testing.

Later on, the wealth of new targets provides entirely new avenues of exploration, slightly dulling the edge of the initial race to check out Mercury, Venus, and Mars. Where the original game often featured multiple players sprinting to fulfill the same tasks, Outer Planets adds so many new things to explore that there’s often enough for everyone to pursue their own pet projects, at least at the outset. In practice, this isn’t usually much of a problem, though it can mean that it will be even longer before everyone is feeling that familiar pressure to raise their flag on distant shores before anyone else does.

That said, the addition of the jovian planets feels perfectly natural, as do their associated dangers and mysteries. Clever players will likely shoot a probe out past Ceres while still hunting for points in the inner system, leading to a space race on two fronts. And the stakes of exploring such distant destinations are raised as the years of any prospective journey are increased. This is the first time, for example, that I’ve bothered increasing the velocity of a ship in order to reach a destination faster. Damaged ships might take a decade to repair rather than one or two, the prospect of manned missions is ever more tenuous, and locales like Neptune feel so terrifically remote that there’s even a lingering sense of loneliness to them.

All in all, Outer Planets earns my recommendation. It might not be quite as svelte as Leaving Earth, but it more than makes up for that with its increased scope. The only thing left is to wonder what the next expansion could possibly add. Kessler Syndrome? Comet docking? Slashed budgets?

Nah, let’s leave that last one to reality.