A galaxy lies open for you to explore.

Endless Sky is a 2D space trading and combat game similar to the classic Escape Velocity series. Explore other star systems. Earn money by trading, carrying passengers, or completing missions. Use your earnings to buy a better ship or to upgrade the weapons and engines on your current one. Blow up pirates. Take sides in a civil war. Or leave human space behind and hope to find friendly aliens whose culture is more civilized than your own.

Downloads are available for Mac OS X and Windows, and many Linux distributions are also supported. Endless Sky is free and open source, the product of a growing community of developers and content creators.

After years of working a factory job, you have finally saved up enough money to apply for a pilot's license and make a down payment on your very first starship. The backwater planet where you grew up only sells three ship models: a shuttle, a cargo barge, and a light interceptor. Depending on which one you choose, you'll start out earning money by transporting passengers, looking for good trade deals, or perhaps mining asteroids or taking jobs escorting freighter convoys. Of course, you are hoping to save up enough money for a much better ship before long.

Human space is a network of two hundred star systems, most of them inhabited, joined by hyperspace links. No one really understands how the hyperdrive works or how the links were initially created, but they say that the strange aliens who live down at the edge of the Rim have other means of travel that allow them to visit other parts of the galaxy.

A merchant captain can earn a living by buying cheap food and luxury goods from the poorer parts of the galaxy and trading it for medical supplies or electronics on richer worlds. But you can often earn a better income by taking on special jobs. The more cargo space you have in your fleet, and the higher your combat reputation grows, the more jobs become available to you.

Of course, if you fancy yourself a hotshot pilot, you might be able to earn income more quickly by starting out in the interceptor and mining asteroids or even hunting pirates. In fact, no matter what ship you choose, if you stray into the wrong parts of the galaxy you're sure to run into pirates sooner or later.

The trouble is, you're flying the wimpiest ship in the galaxy right now, so early on your piloting skills will be useful mostly for dodging missiles and running away from combat.

Fortunately, there are hundreds of different "outfits" - weapons, engines, power generators, cooling systems, and much more - that you can buy to upgrade your ship. With the tiny ship you start out in, equipping it will always involve tradeoffs: buy better engines, to help you run away from pirates? Or sell all the non-essentials to make room for more cargo? Stock ships tend to be well balanced, but once you start modifiying your ship you'll also have to worry about energy requirements and heat dissipation.

Once you've paid off your mortgage (or qualified for a bigger one) it's time to think about buying a better ship, either to build a fleet or to replace your flagship. About 50 different models of ships are available in human territory, anything from massive freighters to powerful warships to quick, nimble scoutships. And, every once in a while you hear rumors that people have traveled beyond known space and discovered alien civilizations with technology far superior to your own.

To really make your mark in the galaxy, you'll have to choose which factions to side with, both in human space and beyond. Only one major story line has been written so far, allowing you to take part in a rebellion that reshapes human space. Endless Sky is designed to make it as easy as possible to create new content to add to the game, and people are hard at work on other story lines, as well as new alien species, ships, and outfits.