I can't keep in orbit. Seeking help, not working

[Tsuki_Me]

Okay, so I bought this game a couple of days back in pure interest. I have spent quiet some time in the game learning(in science mode). I can't reach orbit, although I can get my apoapsis to 75km. I can't get enough fuel to circularise the orbit. The ship design is very simple with 800litres of fuel in ascending stage and 400 in orbiter stage, I am using swivel engines and a solid booster in the start of the launch. Ain't no tutorials saving me... Kindly help! 

[AlamoVampire]

Have you tried adding more fuel/engines to give you the dV needed to circularize? 800 fuel sounds way low. Id suggest some solid fuel boosters that you can stage away as they burn out. Hope that helps!

080408202023

[James Kerman]

Welcome to the forum @Tsuki_Me! 

Rather than using liters of fuel we use delta V (dV), as this is calculated to include the mass of your vehicle as well. There is a readout in the VAB that will show your vessel's dV (please note that you will need to change between atmospheric and vacuum mode for the respective stages of your flight). To get to low Kerbin orbit you'll need a design that has around 3,200 - 3,500dV combined and a reasonably efficient flight profile. Additionally the engines have different efficiencies measured as specific impulse (ISP) and solids have high thrust but low ISP so they are great for getting heavy rockets off the ground but are not as efficient as the liquid fuel types. A good early combination is to have a swivel as your first stage (as it has a high ISP at sea level) and a terrier as your vacuum stage as it has a high ISP above around 15,000m.

Edited August 20, 2023 by James Kerman
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[Tsuki_Me]

Thanks, but when i add more fuel and engines, the mass increases thus fuel is expended on lifting the ship of the ground

[Tsuki_Me]

34 minutes ago, James Kerman said:

Welcome to the forum @Tsuki_Me! 

Rather than using liters of fuel we use delta V 9 (dV), as this is calculated to include the mass of your vehicle as well. There is a readout in the VAB that will show your vessel's dV (please note that you will need to change between atmospheric and vacuum mode for the respective stages of your flight). To get to low Kerbin orbit you'll need a design that has around 3,200 - 3,500dV combined and a reasonably efficient flight profile. Additionally the engines have different efficiencies measured as specific impulse (ISP) and solids have high thrust but low ISP so they are great for getting heavy rockets off the ground but are not as efficient as the liquid fuel types. A good early combination is to have a swivel as your first stage (as it has a high ISP at sea level) and a terrier as your vacuum stage as it has a high ISP above around 15,000m.

Woah! Thanks... I did not know a lot of these. I still did not unlock terrier engine, so will try to and follow your steps.

[Vanamonde]

3 hours ago, Tsuki_Me said:

Thanks, but when i add more fuel and engines, the mass increases thus fuel is expended on lifting the ship of the ground

Yes, that's the classic problem all rockets face.  Rather than add to the existing stages (which as you have seen can actually hold them back) try adding another stage under the ones you have. Worry about things like efficiency after you get some experience with getting there at all. 

[Tsuki_Me]

On 8/20/2023 at 6:48 PM, James Kerman said:

Welcome to the forum @Tsuki_Me! 

Rather than using liters of fuel we use delta V (dV), as this is calculated to include the mass of your vehicle as well. There is a readout in the VAB that will show your vessel's dV (please note that you will need to change between atmospheric and vacuum mode for the respective stages of your flight). To get to low Kerbin orbit you'll need a design that has around 3,200 - 3,500dV combined and a reasonably efficient flight profile. Additionally the engines have different efficiencies measured as specific impulse (ISP) and solids have high thrust but low ISP so they are great for getting heavy rockets off the ground but are not as efficient as the liquid fuel types. A good early combination is to have a swivel as your first stage (as it has a high ISP at sea level) and a terrier as your vacuum stage as it has a high ISP above around 15,000m.

 

21 hours ago, Vanamonde said:

Yes, that's the classic problem all rockets face.  Rather than add to the existing stages (which as you have seen can actually hold them back) try adding another stage under the ones you have. Worry about things like efficiency after you get some experience with getting there at all. 

Wow!... Thank you so much guys. I actually got into orbit with Jeb. 

FUN FACT: I didn't have enough fuel to reach back to Kerbin, used all of it to rise the periapsis above 70km. I actually overburnt because my apoapsis was over 105km. Terminated and killed Jeb in the process.

Thanks once again!

Edited August 21, 2023 by Tsuki_Me

[Vanamonde]

Success! (Of a sort.) Congratulations.