How to get off the planet

[Marauding Conan]

Hej there. New to the game. Loving it so far. Learning how to make the different blocks is a blast.

However, whilst playing survival mode, I have not been able to get off the planet. Built different ships with different configurations. But the best one so far multiple hydrogen engines 4 atmosphere engines to aid on the take off. WIth this combinations, I get to about 5km when the speed starts to reduce, I switch off the atmosphere engines and tilt 90 degrees (just like in splitsie's video) engaging the main thrusters and it goes fast .... for about 1km. Then after that, no matter what I do, I am only going down.

I thought the problem might me that I need more thrust. But I am up to 4 large thrusters in a small grid and it always does the same thing.

I have tried to make the transition at lower altitudes but does not help. The only difference I can see from my set up and splitsie's is that I have no reactor as I have not found any uranium.

Can anyone explain how to get off a planet? Thanks in advance.

[Realm Walker]

best is to overwrite the thrusters accelarating you upward and reducing the force as much as possible without going below highspeed.
This technik allows for superefficient take offs.

[Dan2D3D]

Hi, I prefer to use batteries + Hydro tanks with the needed forward or upward thrusters that I will trun Off some once in space to save Hydrogen so I can build a station at 30km around the Moon cause that is where I find Uranium faster.

I always build a small Moon station at the flat area next to one of the ice Poles cause all ores -1 can be found over there

[jafiwam]

Atmospheric thrusters need boost with batteries.

Hydrogen thrusters need boost with hydrogen tanks.

You create power or H2, store them away, and then use them for boost.

Do not rely on your creation method for power or H2 to run active thrusters.

I made a jack of all trades ship to get out to space with two large atmo thrusters, two large hydrogen thrusters and lots of storage for power and H2. It worked great.

The transition is right, go up on atmos until you slow down a bit then use hydrogen. TURN OFF INERTIAL DAMPENER and boost on / off to go up with hydrogen thrusters. Otherwise you are just pushing against the 100 meters per second limit and wasting fuel.

[NYVS]

*Do you have enough hydrogen thrust and fuel.

Atmospheric thrusters tend to be on the higher end of massed components; and require quite a bit of power drain to stay aloft. And then once you switch over to hydrogen, you'll start guzzling the fuel. If you're applying thruster override with your inertial dampeners turned off; then might I ask how many fuel tanks you have incorporated into your design? A good rule of thumb if your having no problem ascending to 5km on atmo, is to have at least one fully fueled H2 tank per H2 thruster for the rest of the trip.

[Realm Walker]

sure, turn off the backward thrusters before bridging, i forget to say.
I actualy use a small ship with two hydrotanks that can reach space with less than halve of its fuel

[Doom]

Originally posted by Marauding Conan:

Can anyone explain how to get off a planet? Thanks in advance.

You need sufficient LIFT, and enough FUEL.

Hydrogen engines devour hydrogen almost instantly, and if you're using small fuel tank it will be gone once you blink.

To calculate lift... go to space engineer wiki and look for FORCE engine provides.
https://spaceengineers.fandom.com/wiki/Atmospheric_Thrusters

For example, small atmospheric thruster on a small ship produces 340 kN (kilonewton of force).
For simplicity, you can drop one zero and it will be roughly how much this ship can weigh without losing ability to hover in kilograms. For example, one atmospheric small thruster on a small ship can support roughly 34 000 kg of mass on earth-like gravity. Technically this is not precise, because you need to divide force by gravity, meaning 340 kN will actually be able to support 34693 kg of mass in earth gravity and not 34000, but it is a decent rule of the thumb, unless you really want to visit alien planet.

Now... this applies to thrusters pointing DOWN. Only they count for generating lift.

Now that lift calculation is out of the picture, to leave gravity well, you need enough fuel to keep countering gravity until you're in zero-gl. It might be a good idea to keep in mind that it is impossible to fly faster than 100 m/s in unmodded game, and gravity drops off with height, so you don't necessarily need to keep blasting thrusters at maximum force all the way up. You can for example, disable dampeners (Z) fly up, and keep blasting just enough to keep your speed above zero, or ideally somewhere above 90 m/s. This will conserve fuel.

Long story short, to go into orbit, make any ship with truckload of hydrogen, attach a cockpit to it, sit on it, and check how much this thing weighs at bottom right. Then keep adding thrusters until total lift generated by downward pointing thrusters is larger than weigh of your ship. Then load the ship with hydrogen, blast off, disable dampeners, and keep pressing space to maintain your speed at high value (>= 90 m/s or so... ). Enjoy zero g.

Also be ready to scream profanities on the way down afterwards, and it might be a good idea to set a GPS marker for your base before you leave for orbit.

[Marauding Conan]

Originally posted by Doom:

Originally posted by Marauding Conan:

Can anyone explain how to get off a planet? Thanks in advance.

You need sufficient LIFT, and enough FUEL.

Hydrogen engines devour hydrogen almost instantly, and if you're using small fuel tank it will be gone once you blink.

To calculate lift... go to space engineer wiki and look for FORCE engine provides.
https://spaceengineers.fandom.com/wiki/Atmospheric_Thrusters

For example, small atmospheric thruster on a small ship produces 340 kN (kilonewton of force).
For simplicity, you can drop one zero and it will be roughly how much this ship can weigh without losing ability to hover in kilograms. For example, one atmospheric small thruster on a small ship can support roughly 34 000 kg of mass on earth-like gravity. Technically this is not precise, because you need to divide force by gravity, meaning 340 kN will actually be able to support 34693 kg of mass in earth gravity and not 34000, but it is a decent rule of the thumb, unless you really want to visit alien planet.

Now... this applies to thrusters pointing DOWN. Only they count for generating lift.

Now that lift calculation is out of the picture, to leave gravity well, you need enough fuel to keep countering gravity until you're in zero-gl. It might be a good idea to keep in mind that it is impossible to fly faster than 100 m/s in unmodded game, and gravity drops off with height, so you don't necessarily need to keep blasting thrusters at maximum force all the way up. You can for example, disable dampeners (Z) fly up, and keep blasting just enough to keep your speed above zero, or ideally somewhere above 90 m/s. This will conserve fuel.

Long story short, to go into orbit, make any ship with truckload of hydrogen, attach a cockpit to it, sit on it, and check how much this thing weighs at bottom right. Then keep adding thrusters until total lift generated by downward pointing thrusters is larger than weigh of your ship. Then load the ship with hydrogen, blast off, disable dampeners, and keep pressing space to maintain your speed at high value (>= 90 m/s or so... ). Enjoy zero g.

Also be ready to scream profanities on the way down afterwards, and it might be a good idea to set a GPS marker for your base before you leave for orbit.

Thanks for that explanation. I had not figure on the thrust to weight ration... as I didn't know if it was modelled but the hints were there. So... turns out my design is grossly over weight... by a factor of 10

[Rox]

I really wish somebody had the enthusiasm and time to make a website for SE like there are for some other games that list the important factual data on all the parts/blocks/modules that are used for building ships/structures AND extracts all the important numerical data from the actual game files and has it auto-updated every time the game is updated. One of the problems with using anything other than the live game data files is that Keen routinely and silently change the numbers, so all the existing wiki sites with such information are always untrustworthy and often incorrect :/ The other problem is that the data in the files is spread over dozens of files in an inconsistent format with unclear and inconsistent naming conventions and undeclared units.

[Raider Deci]

Speed & power my friend. So thrusters. Lots of thrusters. With lots of fuel. A classic combination that never fails.


But I would recommend the mod that makes hydrogen 10x more efficient. It simply makes things more enjoyable since we have a whopping 3 kinds of thrusters to choose from during the entirity of the game.

[Doom]

Few more details.

In general, in space engineers things are using newton laws.
F = ma.
Force equals mass multiplied by acceleration.

Using this formula, you can determine how much force you need to make ship reach target speed.

For example, in zero g, you want to have 10000kg mass ("m") go from 0 to 10 m/s in a second. 10 m/s gain in velocity per second is acceleration of 10 (m/s^2 or m/(s*s), meters per second squared)

To make this happen, you need to produce F = m * a = 10000kg * 10 m/s^2 = 100000 newtons.
If you go to space engineers engineer wiki, you can see this article:
https://spaceengineers.fandom.com/wiki/Thruster_Comparison

Let's say we're making a small grid and use small ion thrusters.
1 small ion thruster is 14 kN (kilonewton) or 14000 newtons. So, to produce 100000 newtons force we need 100000/14000 = 7,142.... rounding it up, 8 small thrusters.

That's in one direction. To maintain the same maneurability in all direction, we need 6 sets of those, meaning, 8*6 = 48 thrusters.

The next thing is that 48 ion thrusters weigh 24 * 121 == 5808 kg. So from your original 10000kg, 5808 is spent on thrusters alone, just so you can go from 0 to 100m/s in 10 seconds.

You can reduce this by being less greedy with acceleration. For example,. if you're content with going from 0 to 100 m/s not in ten, but in 40 seconds, then your target acceleration is 2.5 m/s^2 (100 m/s divided by 40 s), the pull you need to generate 25000 newtons and not 100000, and that means, you need 2 thrusters per direction (25000/14000 = 1,78, rounding up it is 2) and not 8. Thus total number of small thrusters on your ship will drop to 12, which will weigh only 1452 kg.

This is in zero G.

On a planet, to go anywhere, you first need to be able to hover. The reason why ship stays on surface is because it is constantly affected by gravity, which is a force pulling downwards, which is calculated as F = m * g, where g is gravitational acceleration for this particular planet.

For earth, g is 9.8 m/s^2. For moon it is 2.45 m/s^2, and Alien planet has the highest gravity of 10.78.

To hover, you need to counter this force, by having thrusters firing down at least this amount.

For example, for atmo thrusters on small grid on earthlike, and 100000kg mass (using 100k instead of 10k, because atmospheric thrusters are stronger), you have to counter 980000 newtons of gravity to hover. With small thruster producing 65 kN of force (65000 newtons), you need... 980000/340000 = 15,07 , roundign up... 16 thrusters to hover in air, which weigh 539*3 = 8624 kilograms.

Once you countered gravity pull, it is the business as usual. You can calculate force you need based on ship mass and acceleration you want, and the rest works like before.

EXCEPT that you need to keep in mind that for downward facing thrusters you need additional force to counter gravity.

-------
There are also gotchas and tricks

Gotchas: batteries have maximum output. For example, small ship battery (large one), can operate at maximum output of 4.32 megawatts while having capacity of of 1.08 megawatt-hours. First, it means that at maximum output it will completely drain in 15 minutes (capacity in mwh * 60 minutes / power = 1.08 * 60/4.32 = 15 minutes).
Second, it means it can only support support limited number of thrusters. 4.32 Mw/ 701 kW = 6.1 rounding down - 6 small atmospheric thrusters firing at full force. (There are two conflicting source of information on thruster power consumption - some say it is 600, other say it is 701, calculation is the same). So if you have one battery and need to fire more than that number of thrusters, they won't activate and that may lead to you crashing down. This is something to keep in mind when building lift thrusters. In general, you'd want enough energy to keep all lift thrusters firing at all times, while also having enough energy to keep one group of meneur thrusters firing in one direction.

Another gotcha is that hydrogen requires fuel and fuel has weight. This sends you to the realm of Tsiolkovsky's rocket equation and makes calculations more interesting, although you can just load fuel tank with ice, gas tank with hydrogen, and calcualte how much thrusters you need to lift this.

Tricks. You can conserve fuel by putting your lift thruster into action group separate from the rest of the thrusters, then shut them off once you're no longer in gravity well. For example, you can have huge hydrogen thruster pointing down, use it to lift off into space, but once you're there, you can shut it off so it doesn't burn fuel anymore.

You can simplify calculation of lift thrusters using following trick. Let's take one battery and 6 small atmo thrusters. This will produce thrust up to 65kN * 6 = 390 kN (390000 newtons) and will weigh 6*539 + 1040 = 4274 kilograms.
Here's fun part. It takes m * g force for this thing to hover, and the rest is added lift you can use for cargo. You can divide the rest of the lift by gravity and you'll get how much more mass this thing can hold floating above ground. Basically, F_lift = thrust - gravity * mass. And Lift_mass = F_lift/gravity. So, on earth like, this thing requires 41885,2 newtons to hver, while producing 390000 newtons of lift. Free hover force you can use for cargo is 390000 - 41885,2 = 348114,8 newtons, which, on earthlike will allow you to hold 348114,8/9,8 = 35521 kilograms of cargo in air for 15 minutes. So, rather than running all the calculations again, each time you need ability to hold more cargo, you can just calculate how many 6thrusters + 1 battery sets you need.

That's the rough idea of it.

Originally posted by Marauding Conan:

Originally posted by Doom:

You need sufficient LIFT, and enough FUEL.

Hydrogen engines devour hydrogen almost instantly, and if you're using small fuel tank it will be gone once you blink.

To calculate lift... go to space engineer wiki and look for FORCE engine provides.
https://spaceengineers.fandom.com/wiki/Atmospheric_Thrusters

For example, small atmospheric thruster on a small ship produces 340 kN (kilonewton of force).
For simplicity, you can drop one zero and it will be roughly how much this ship can weigh without losing ability to hover in kilograms. For example, one atmospheric small thruster on a small ship can support roughly 34 000 kg of mass on earth-like gravity. Technically this is not precise, because you need to divide force by gravity, meaning 340 kN will actually be able to support 34693 kg of mass in earth gravity and not 34000, but it is a decent rule of the thumb, unless you really want to visit alien planet.

Now... this applies to thrusters pointing DOWN. Only they count for generating lift.

Now that lift calculation is out of the picture, to leave gravity well, you need enough fuel to keep countering gravity until you're in zero-gl. It might be a good idea to keep in mind that it is impossible to fly faster than 100 m/s in unmodded game, and gravity drops off with height, so you don't necessarily need to keep blasting thrusters at maximum force all the way up. You can for example, disable dampeners (Z) fly up, and keep blasting just enough to keep your speed above zero, or ideally somewhere above 90 m/s. This will conserve fuel.

Long story short, to go into orbit, make any ship with truckload of hydrogen, attach a cockpit to it, sit on it, and check how much this thing weighs at bottom right. Then keep adding thrusters until total lift generated by downward pointing thrusters is larger than weigh of your ship. Then load the ship with hydrogen, blast off, disable dampeners, and keep pressing space to maintain your speed at high value (>= 90 m/s or so... ). Enjoy zero g.

Also be ready to scream profanities on the way down afterwards, and it might be a good idea to set a GPS marker for your base before you leave for orbit.

Thanks for that explanation. I had not figure on the thrust to weight ration... as I didn't know if it was modelled but the hints were there. So... turns out my design is grossly over weight... by a factor of 10