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Kerbal Space Program is a multi-genre game where players create their own space program.
Release Date: Mar 30, 2013
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Early Access Game

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Note: This Early Access game may or may not change significantly over the course of development. If you are not excited to play this game in its current state, then you may want to wait until the game progresses further in development. Learn more

What the developers have to say:

“KSP is still under development. This means the game will be improved on a regular basis, through updates that add new features, content and bug fixes, so make sure to check back for new versions.

The game is being built as a sandbox first, so there are no objectives yet, but we want you to try it out and have fun with it already. You're free to build anything you can think of, and there is an entire Solar System to explore.

During development, KSP is available for purchase at a discounted price, which will gradually increase up to its final retail price as the game nears completion. So by ordering now, you get the game in its current state, and you'll get all future updates for free.”
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KSP: Asteroid Redirect Mission is Officially Released!

April 1st, 2014


I'm very happy to announce that the Asteroid Redirect Mission patch for KSP is now officially released!


This is a very special update in many ways, not least of course is that it was made in collaboration with NASA, to make sure our Kerbal version of the Mission was not only true to its real-life counterpart, but that it was also fun, educational, and in keeping with KSP's style, free to be performed in any way you can think of. Want to re-enact the exact mission profile NASA is planning? Go for it. Want to send up enough rocket fuel to lift an office building and slam on the retrograde brakes? That's also an option. Want to not do any of those things and just use the Advanced Grabbing Unit to choose which Kerbals go and which stay? Erm... sure.

This has been, without question, the largest update we've ever done, not just in terms of development time, but most importantly in terms of the scope of the changes made. No other update has had so many different areas improved on at the same time. We usually focus on a single area to work on, but this time, we really felt the need to make a noticeable improvement in the overall playing experience, especially around flight planning and advanced deep-space missions.

So, Here are the highlights for this update:

* Asteroids:
Kerbin is no longer alone in its orbit. Nearby are countless objects that buzz in and out of its sphere of influence, some flying by harmlessly, others on impact trajectories. Ranging in size from just a few meters through 5 size classes up to gigantic objects weighing thousands of tons, these new objects should provide a new challenge for both new and veteran players. Each asteroid is procedurally generated, so no two are the same. Also, asteroids can have samples taken from them by EVAs, providing a constant source of valuable science data, right on the edge of Kerbin's SOI.

* Object Discovery and Tracking:
Before you set out after an asteroid, you first need to identify and track them using the Tracking and Discovery features on the Tracking Station Facility. Select one of the unknown objects spotted near Kerbin, and start tracking it actively to reveal more information about it. Also mind that untracked objects can be lost if they're left unobserved for too long.

* The Advanced Grabbing Unit (aka "The Claw")
As the name probably implies, this new part is the means by which asteroids can be captured to be redirected. Just arm the device, approach the target carefully, and the claw will do the rest. It's like a docking node, but without the need for a mate node on the other side. Better still, the AGU can be used to grab on to much more than just asteroids. In fact, it can pick up just about anything, even Kerbals.

* New SLS-inspired Size 3 parts:
We've added a host of new parts, featuring the largest engines and fuel tanks ever seen in KSP. These new parts were designed based on NASA's upcoming Space Launch System, and they pack a huge amount of rocket power.

* Completely Overhauled Part Joints:
We have completely re-done the way parts attach to one another, to allow for much greater flexibility and control over each joint. Joints are also more accurate and stable, as both jointed sides are now anchored at the attachment node (this wasn't possible before the Unity 4.3 update).

There's more. This update also features a host of small, and some not-so-small tweaks and improvements to usability, giving many features added a good while ago a much needed refurbishing, and adding a lot of the little things we never got a chance to add when we first implemented them.

Check this post for the complete changelog

Release Notes:
* The ARM Patch (0.23.5) should not break backward-compatibility with previous saves. That said, however, do mind that we cannot account for mods, so don't expect them all to work perfectly. If you experience any problems, make sure you try a clean install of the game without any mods, and a new clean save as well.

* The ARM Patch is available just as any other update. You should be auto-updated next time you run the game. Just make sure you haven't disabled Steam's auto-update system for KSP.

Happy Launchings, and have fun!!


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About the Game

Kerbal Space Program is a multi-genre game where players create their own space program.

In KSP, you must build space-worthy craft, capable of flying your crew out into space, without killing them. At your disposal is a collection of parts, which must be assembled to create a functional ship. Each part has its own function and will affect the way a ship flies (or doesn't). So strap yourself in, and get ready to try some Rocket Science!

The game is being built first as an open sandbox, you're free to build anything you can think of, and fly it wherever you want, even into orbit and out to other planets and moons throughout the Kerbal Solar System. The first draft of the career mode is also available now, it is still in development, so expect more features!

Key Features

  • The Vehicle Assembly Building and the Space Plane Hangar allows players to build spacecraft out of any imaginable combination of parts.
  • Fully-fledged, Physics-based Space Flight Simulation ensures everything will fly (and crash) as it should.
  • Take your Kerbal crew out of the ship and do Extra Vehicular Activities.
  • Fly out to Moons and other Planets.
  • Procedural Terrain delivers detailed terrain at a vast scale. The Kerbal Planet is 600km in radius!
  • Mod-enabled, allows players to create new content and modify the game.
  • Ship systems. Keep an eye out for engine temperatures and fuel levels, and try not to explode.
  • Build ships with multiple stages, and jettison parts away as they burn out.
  • Full control over the ship’s setup allows for complex ships and advanced functionality.
  • Dock spacecraft together to build Space Stations, Massive Starships, or even surface bases on other worlds.
  • Manage your crewmembers, hire them, and send them out into space and make them into heroes.
  • Research and Develop new technologies to advance your Space Program.

Planned Features

  • Take on Missions to attract interest in your Space Program.
  • Discover new worlds and expand the scientific knowledge of Kerbalkind.
  • And a whole lot more!

PC System Requirements

    • OS:Windows XP
    • Processor:Core 2 Duo
    • Memory:3 GB RAM
    • Graphics:SM3 512MB VRAM
    • Hard Drive:1 GB HD space
    • OS:Windows 7
    • Processor:Core i3
    • Memory:4 GB RAM
    • Graphics:SM4 1GB VRAM
    • Hard Drive:2 GB HD space

Mac System Requirements

    • OS:Snow Leopard
    • Processor:Dual Core Intel
    • Memory:3 GB RAM
    • Graphics:SM3 512MB VRAM
    • Hard Drive:1 GB HD space

Linux System Requirements

    • OS: Linux (Most distros should work)
    • Processor: Core 2 Duo
    • Memory: 3 GB RAM
    • Hard Disk Space: 1.5 GB HD space
    • Video Card: SM3 512MB VRAM
Helpful customer reviews
2,139 of 2,207 people (97%) found this review helpful
312 products in account
8 reviews
79.6 hrs on record
Early Access Review
One day my daughter came home from school and asked me "Have people actually travelled to the Moon? How is it possible?"

Two years ago, I would have answered "yes, but I don't really know how. It's very complicated, with lots of math and science. You might learn about it in a physics class in 10 years time."

Instead, I answered "Here, let me show you." and fired up Kerbal Space Program. We built a moon rocket and launched it, me steering and she hitting the separation detonation buttons when needed. 30 minutes later we had landed on the moon.

Thank you, Squad, for enabling me to give that answer.
Posted: March 19th, 2014
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357 of 375 people (95%) found this review helpful
61 products in account
6 reviews
99.6 hrs on record
Early Access Review
I score this Simulation game 12/10, just hit the buy button!

Kerbal Space Program is pure MAGIC! On the facade it comes across as something with the depth of Angry Birds and the looks of a crappy looking 3d rollercoaster tycoon and the unsuspecting gamer is easily fooled. However, there is a reason this is one of the most played games on steam! There's a reason I'm scoring this game 12 out of 10.

Kerbal Space Program is hard to define. But it's a space program simulator. You set out your own missions (like fly somewhere, like the moon or another planet) and everything that goes with it. Designing the vehicle (the lander, the rover, whatever), designing the means to get it there (ie a rocket) and you have to get there. There are no concessions, you will learn how real spaceflight works when you figured out how to get there. It's so beautifull once you actually have a space program going. It's so magical to be able to explore such an immense ingame world. You can feel like such a pro when you land probe #2 really near probe #1 while the journey took many millions (billions even, there is no describing it) of kilometers. I believe the earthlike home planet, Kerbin, has a cicumference of about 4000 km! And there are many other worlds and moons too! Even a gas giant! The game isn't finished yet, but I don't care. They can't fail anything anymore. Just buy it. Or wait for a sale and then buy it. Whenever you do buy it, you won't feel ripped off! I guarantee you that! The learning curve is immense, but almost every Kerballer shoots pictures, makes videos, writes reviews and shares knowledge... it's incredible!

The game is very educational too. I thought I understood quite a bit about orbits, but I learned so much. You will learn about orbits, what different charactaristics mean for planets and landing on them, how rockets behave, and so much more. There is so much to do! An entire solar system to explore, planets and moons, space stations to build, whatever you want. It's like lego for all ages. The only requirement is that you find space exploration worth the effort, if you find nasa/esa/other space agency worth the effort, I recommend this game. I also recommend this game if you like lego for that matter, or simulations of any kind.

You start the game, you slap together a simple rocket, launch it. It feels a lot like Angry Birds when you have to build machines for the pigs. A few rockets later and you reach space. At that point, the game changes for the first time. It looks and feels more like 2001: a space oddisey! The first rocket I managed to get to space was so powerfull and uncontrollable (I also didnt know how to control it yet), that it passed the moon and ended up in orbit around the kerbal sun at a lethal height. It was still just fun and games. But addictive nonetheless! It's fun to explore such an immense ingame universe: an entire solar system!

Then I decided it was time to stay in space and also in orbit of the homeplanet. I watched the space shuttle launches and noticed them rolling and pivoting the rocket right after launch. Trying to get some horizontal speed and not just vertical. I also remembered what an astronaut once said on youtube: orbiting is not hanging weightless around earth, it's moving faster horizontally then you're falling vertically. So, I learned how to make an orbit. Then I learned to make a round orbit. And I set the next mission of my personal space race: the moon.

Every time I played I tried at least once to fly a rocket to the moon. After a rocket or 8 I finally managed to land something on the moon in one piece. One rocket later and I was there with a live kerbal planting a flag. I felt like such a pro. Then I left Kerbal alone, waited for a few patches. Only to hear from a friend he was trying kerbal, I decided to share all of my knowledge. After one night of playing Kerbal with him, I was hooked to Kerbal again. And this time, Kerbal changed again!

My new rocket had 1/3 of the bits and pieces the last one had and I learned so much about orbits and how they work that I decided it was time to fly to another planet! I chose Duna and Eve, that's the equivalent of Mars and Venus. After landing small probes on both planets and having a satelite in orbits, I wanted to land a live kerbal on both. While landing on Duna my first Kerbals lost their power supply, so I decided they need housing and a mobile lab to investigate the planet. It turned out that the charactaristics vary on the surface!

After working a few nights on a massive truck, I couldn't balance the rocket. So I had to think like an engineer, balancing the truck, the spacecraft and then every stage of the Rocket. After 6 nights of playing I had produced the first stable rocket, not powerfull enough. After 2 more nights the second: not enough fuel in the first stage. And now, after 2 more nights of just putting together what I had in my mind it's still not completed! Kerbal changed from addictive fun and games into a mindboggling engineering puzzle. I just can't let it go, I have to complete the rocket. I will send this oversized, 8-wheeled monstertruck to mars! In total I have already spent well over 35 hours in this one mission, a gamechanger. You don't have to go this far to feel satisfied with this game. My PC (I have a radeon 7950, nvidia chips have better physics) also thinks I have gone too far and my framerate is down to slideshow mode. I went from 300 parts in my first succesfull moonrocket, to less then 100 in my second one that also probed Duna and Eve to now well over 1500 parts in this incredible monster. I went from slapping somehing together for fun to putting something together with the help of ingame calculators, a real calculator, and dozens of test flights of every seperate part of the rocket and the mission.

No matter how intense you will play Kerbal, you will be enjoying it intensely! To me it blew my mind, and I sit here with sweaty palms more then in any other game over the last decade! As soon as I'm done with giving my Kerbals on Duna what they need to survive, I need to learn how to dock in space. It's one of the last main hurdles I must take. When I have mastered this skill I know for a fact that the game will change for me once more. Just imagine building something in space using more then one flight! Building it in modules, getting the rockets balanced, plan the flight to the planned orbit, dock, next flight! Oh man, I can't wait! But everytime I think about that, I think about that damned monstertruck of mine. I must get it to Duna! (edit: the Truck is on Duna, long story... but wheels are broken and the kerbal is in the lab instead of the cockpit, so now the truck needs a relief effort as well...)

And oh yeah... the game is already so good, but it isn't done yet. It only gets better and better! They even announced multiplayer! I don't know how this would work, but it is good to know that this game might even be appreciated more by me later then it already is!

Check out my videos at http://steamcommunity.com/id/tiberiusbrain/videos/ and more are coming as I complete more personal achievements! Share yours in the comments!
Posted: January 15th, 2014
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169 of 179 people (94%) found this review helpful
584 products in account
1 review
291.9 hrs on record
Early Access Review
This is an incredible game, I've almost got 300 hours into it and I'm still looking forward to firing it up nearly every day.
There's a lot of reasons to buy this game:

* if you love space, this game will get you there, first hand, and let you have your hand at designing space crafts (and planes), flying them, and of course, crashing them in big glorious explosions

* you will learn a lot about space, physics, orbital mechanics, aerodynamics, etc... this really happens, I have two friends that are rocket scientists (one does ion drive research, the other designs micro-satellites, I work at a large university), and after playing this game for a few months, I could easily talk to them about their work, where they drop terms like ISP, TWR, retrograde, normals, etc, terms that I now fully understand

* the game is very approachable, you can play in "career mode" which walks you though the beginning steps of putting a rocket into space, to orbiting, to visiting the Mun and beyond. If you need more help, the YouTube scene is quite impressive, with people like Scott Manley producing really professional (and charming) video tutorial series. I am not a lover of simulation-type games, I play mostly FPS's and RPG's, but I found this game quite easy to pick and up get into.

* while approachable, this game is certainly not easy, for example, landing and returning from Eve (the Venus-like planet in the Kerbin system) is one of the hardest tasks in the game, and while most of the game is fairly non-stressful in its nature, landing spaceships is a tense experience, especially when Jeb's life is on the line! For those that find it difficult to master some of the more difficult tasks, there are impressive control mods like MechJeb2 where you essentially point at a spot on a planet and press the "Land There" button, MechJeb does the rest.

* the game has a unique charm to it, in the game you are progressing through the space race for the people of the Kerbin panet, you'll get to know and love the kerbalnauts that will fly your craft, especially Jebediah Kerman, pilot extraordinaire and fearless hero to the Kerbin people

* the community for this game, is active, organized, and quite friendly, mostly found on Reddit and the Squad forums, you can get any question answered, or read mission reports from someone's latest mission, or get news on upcoming updates for the game. The only time you see people getting belligerent on these forums is when some is misbehaving toward others
Squad is actively developing this game, each release (every new months) bringing a lot of new features and parts to build with, and just this week the update to KSP brings many new rocket parts built in collaboration with NASA plus a mission to save Kerbin from killer asteroids!

* the mod scene for this game is extremely impressive, from new real-life inspired rocket parts (so you can build your own Saturn V), to impressive new systems that enable for example planetary mining (so you can get more fuel on route to your target), to just plain fun mods like the nuclear pulse rocket, which explodes varied-sized nuclear bombs behind a large plate to produce thrust (scientists actually design this beast in the 50's)

* the endgame is rich and deep: once you've completed career mode, many KSP players switch to the realism mods, which give you the real solar system, truly deadly reentries, realistic communication constraints (that require building satellite networks), more realistic aerodynamics modeling (e.g., Ferram's amazing FAR mod), real life-support constraints, etc. that make for a significantly more challenging and rewarding experience; if that doesn't trip your trigger, the forums have organized challenges with leaderboards, to see who can, for example, get to the Mun with the least number of parts, or eject the most Kerbals out of the solar system, all great fun with the competitors meticulously documenting their missions

If these things sound interesting to you, get this game! It was the best $25 bucks I ever spent!
Posted: April 2nd, 2014
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492 of 691 people (71%) found this review helpful
100 products in account
8 reviews
1,440.9 hrs on record
Early Access Review
Buy it.
Posted: March 10th, 2014
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61 of 62 people (98%) found this review helpful
75 products in account
9 reviews
1,957.9 hrs on record
Early Access Review
This game has honestly changed my life. I have always thought NASA and space flight was cool but it was nothing I ever really put any thought into. But since I first played Kerbal Space Program a passion for space flight grew in me. Since then almost all of my free time has been dedicated to finding out anything and everything I can about NASA history, human spaceflight, and events current in space. I have since participated in the US Space & Rocket Center’s Advanced Space Academy, visited the Kennedy space center, made contact and met with an astronaut, as well as established a relationship with somebody high up in the NASA chain. I My future will forever be changed by this game, so yha... buy it
Posted: April 7th, 2014
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