Sol

Who Am I

Hello! My name's Austin Sellers - I'm a huge space nerd and I love talking about all the wild and interesting secrets of our solar system. I had the idea for this board game while I was taking an interplanetary mission design class for my master's program. I wanted a game that was fun to play and could also teach people about space and the real-life interplanetary missions humanity has developed. There are tons of fascinating missions humanity has sent into the solar system over the decades. From the methane lakes of Titan to the 400+ volcanoes on Io and the hidden oceans of Europa, these missions reveal a solar system far grander and stranger than the eight planets we grew up with.

I've worked several different aerospace jobs throughout my career - including working with NASA doing human spaceflight orbital analysis and conjunction assessment, working with SpaceX doing flight safety, and working for the Space Force doing Space Forcey things. My education focused on systems engineering, aerospace engineering, astrodynamics, and satellite design.

Project Sol - Overview

In "Sol", you are a Flight Director managing trajectories, fuel, and environmental hazards to plant your flag on planets, moons, and asteroids across the Solar System. Throughout the game, you will design interplanetary missions to real destinations. Every planet, moon, asteroid, and comet on the board is an actual object in our Sol System, and the flight paths and fuel requirements to reach them are rooted in real physics and orbital mechanics. 

Your goal is to expand across the Sol System and earn Exploration Points by exploring new worlds or establishing permanent colonies on a terrestrial surface. Earn bonuses for crossing major milestones, like navigating the asteroid belts or exiting the heliosphere. Focus on pure cooperative exploration, or play aggressively using tactical cards to disrupt trajectories, disable rival ships, or target enemy bases.

Turn Structure

To navigate the Solar System, players take turns executing a simple, five-phase flight loop for their fleet:

Design Process

I started with some (very) basic prototypes to work out how I wanted to represent trajectories between planets and build the game mechanics. In addition to the base game, I also created an interplanetary lander booklet that provides an overview of all the planets, moons, comets, and asteroids humanity has landed on. These include real-life no-kidding photos of THE SURFACE OF OTHER WORLDS (so cool) in addition to a more detailed explanation of the interplanetary mission design process for the other space nerds out there.

(Very) Basic Initial Prototype

Digital PrototypeFinal DesignI iterated on a few different art styles and eventually landed on the game board design you see now. I ordered some higher-quality prototypes and did more play testing with friends and family. 

What's in the Box

Board

The game includes a large game board (39 in x 18 in), five sets of game tokens, delta-v cards, space exploration cards, dice, rule book, and a special "Planetary Lander" booklet. This booklet is not required to play the game, but gives players a deep-dive into the real-life science and interplanetary missions that inspired the game.

Game Components

The game includes five different colored sets of distinct spacecraft, planetary bases, and flags (for claiming your exploration rights). The pieces shown here are 3D printed, but the production game will have injection-molded components. The game also includes hexagonal tracking cards used to track damage and fuel of each spacecraft, plus two dice to determine environmental hazards on each turn (solar flare, radiation, and failed launches).

Cards

The core gameplay revolves around "Delta-V" cards. These cards are used to fuel the spacecraft and determine how much of the solar system the player can explore per turn. The Delta-V card deck also includes player-vs-player action cards, environmental hazards, and spacecraft upgrades.

The Science of the Game

The game mechanics are based on orbital physics and the planetary bodies on the game board were explored by different real-world interplanetary space missions. During the game, the player receives "Exploration Cards" for exploring different planetary bodies, asteroids, and comets in the Solar System. These cards include interesting facts about each world and discuss the various missions sent to explore them.

In addition the rule book, the game also includes a special "Planetary Lander" appendix. This appendix is not required to play the game, but gives players a deep-dive into the real-life science and interplanetary missions that inspired the game. It includes photos and mission descriptions of all the extra-terrestrial worlds humanity has landed on. It also includes a (relatively) brief overview of how the interplanetary mission design process works. 

While the core gameplay loop is based in real-life physics, there are still many deviations that had to be made in order to make the game playable. One of these more prominent examples is Jupiter. Jupiter is surrounded by ionizing radiation and has a very powerful gravitational influence. In the game, players can build bases on Jupiter's moons and leave to explore the rest of the Solar System fairly easily. In the real-world, this would be nearly impossible from a technological and propulsion perspective. 

Spacecraft also can't hop between planets as easily as they can in the game. Planetary alignments, timing, and fuel determine which planets a spacecraft can visit. Spacecraft often take years to travel between planets and these trajectories are solidified well before launch ever occurs. The goal isn't 100% realism, but to provide a fun way to gain an introductory understanding of interplanetary space exploration.

Kickstarter Schedule

If the Kickstarter goal is reached, manufacturing will take about 3-4 months and shipping will take about 1-2 months. With a projected Kickstarter end date of Dec 15, that will put final delivery to you in June 2027. 

The production-quality prototype you see in the photos uses all the same artwork and specifications that will be used in the full production game. Plastic pieces were 3D printed for the prototype, but will be injection-molded for the full production game. There's a significant set-up cost for tooling and creating molds, so the setup will only begin after the Kickstarter goal is reached. This setup also contributes to the 3-4 month manufacturing timeline.

Even MORE Science!

The rest of this page is devoted to exploring some of the scientific concepts within the game. Understanding these concepts is definitely not a requirement to play the game, but if you've made it this far you're probably a space nerd like me :)

Gravity wells

To launch a spacecraft into space, rockets must expend enough energy to "climb" out of a planet's gravity well. The deeper the well (i.e., the more massive the planet), the more energy and fuel it takes to reach orbit. In the game, the energy required to launch from a planet is indicated by the ΔV printed next to the planet on the game board. Since Earth is larger than Mars, it takes 9 ΔV to launch from Earth, but only 4 ΔV to launch from Mars.

I tried to preserve the concept of gravity wells and ΔV as much as possible without affecting game balance, but some gravity wells had to be adjusted to make the game playable. For example, it takes a much lower amount of energy to launch from the surface of Ceres than indicated in the game, but 3 km/s of ΔV was chosen to make the location more balanced for base building and staging purposes. The gravity wells for the outer planets (such as Jupiter) are also much larger than indicated in the game. However, creating accurate gravity wells would result in the outer planets becoming unplayable and would negatively affect the balance of the game. Jupiter's escape velocity is a massive 60.2 km/s compared to Earth's 11.2 km/s.

Delta-V and Fuel

In space, the energy required for a spacecraft to reach orbit or travel to another planet is represented by ΔV (pronounced “delta v”). ΔV represents the change in velocity a spacecraft needs to reach its destination. For example, it takes approximately 4 km/s (9,550 mph) of ΔV to travel from Earth to Mars. That means if a spacecraft is orbiting Earth, it must burn enough fuel to accelerate 4 km/s (9,550 mph) to exit Earth’s gravity well and put itself on a path to Mars.

Instead of thinking in terms of “distance” or “fuel” required, engineers use ΔV to represent the energy needed to reach destinations in space. ΔV is the most consistent way to represent energy. For example, a heavier spacecraft may require much more fuel than a smaller spacecraft to reach Mars, but the ΔV required will be exactly the same.

Aerobraking

In space, there is nothing to slow down a spacecraft. Therefore, when a spacecraft accelerates to reach a destination (such as Mars), it must also turn around and use its rocket engines to slow down once it arrives. This uses a large amount of fuel that the spacecraft must carry with it to its destination. To save fuel, engineers use aerobraking whenever possible. Aerobraking is when a spacecraft dips slightly into a planet’s upper atmosphere to experience enough aerodynamic drag to slow down without using fuel. However, this must be done carefully to avoid losing too much velocity and accidentally re-entering the atmosphere and crashing into the planet.

Aerobraking typically involves the spacecraft dipping into the atmosphere several times until the spacecraft has slowed down. Aerobraking can only be done around planets or moons with atmosphere. This is why the game allows players to aerobrake when traveling to Mars or Titan, but not when traveling to the Moon or Mercury (due to their lack of a substantial atmosphere).

Gravity Assists

Gravity Assists (GAs) are also called Slingshot Maneuvers. Spacecraft can use the gravity wells of other planets to gain speed without using fuel by diving into a planet's gravity well along a precise trajectory. During a gravity assist, a spacecraft can steal a tiny fraction of a planet's orbital momentum and throw itself deeper into the solar system (due to the conservation of momentum, a gravity assist will actually slow a planet down very slightly). Missions to outer planets often perform multiple gravity assists around Venus and Earth. This saves a substantial amount of fuel but adds several years to the journey.

Traveling from Earth to Mars is relatively fast and can be done directly without any gravity assists. Since planets are constantly moving, launches must occur during very specific windows when the planets are alligned properly. For Mars, this allignment occurs once every 26 months.

Solar Flares and CMEs

The term “Solar Flare” is often used loosely to encompass solar flares and Coronal Mass Ejections (CMEs). A solar flare is a burst of light and radiation that travels at the speed of light. It can disrupt some communications in space but is mostly harmless. On the other hand, CMEs are massive physical clouds of plasma that the Sun launches into space. CMEs may take days to reach the Inner Planets and can physically damage spacecraft and Astronauts caught in the CME’s path through massive radiation overdose. On Earth, magnetic fields deflect the Sun’s solar wind and protect the planet from Coronal Mass Ejections (CMEs).

Magnetosphere and Jupiter

Magnetospheres are large magnetic fields that surround many planets. Jupiter’s magnetic field is uniquely powerful because of its fast-moving metallic core. This also creates a dangerous radiation zone around Jupiter that will destroy spacecraft’s electrical components if they are not properly shielded. 

Io is one of Jupiter’s moons. Its volcanoes spew out about one ton of sulfur dioxide gas per second directly into space. Jupiter's strong magnetic field instantly strips electrons from these gases, turning them into charged ions. This creates the intense radiation zone near Jupiter that would be fatal to the average person within minutes. In reality, Jupiter’s magnetic field also traps radiation from CMEs and results in the radiation belts becoming more deadly. However, game mechanics dictate any spacecraft inside Jupiter’s radiation zone is protect from CMEs to balance the risk of entering orbit around Jupiter.

Terrestrial Planet and Celestial Bodies

In the Solar System, the planets are naturally divided into two distinct groups - the Inner Planets and the Outer Planets. These planets are separated physically by the Asteroid Belt. The Inner Planets are all made of rock, while the Outer Planets are gaseous Ice Giants and Gas Giants.

In the game, every planet, dwarf planet, moon, asteroid, or comet is considered as a “celestial body”. However, “terrestrial planets” are specifically the planets, dwarf planets, and moons that are made mostly of rock and are large enough to build a base on the surface. For example, Saturn does not have a solid surface, so players cannot build bases on the planet. However, Saturn’s moons are considered “terrestrial” and players can build bases and launch missions from these locations.

I'm excited to share this game with you and I hope you enjoy learning more about our awesome Solar System!