Space Cannon

[Jonfliesgoats]

When I was a kid there were proposals to launch objects into orbit with powerful guns.  Has anyone tried this in KSP?

[wibou7]

I don't think it would be possible without heavily modded parts and a good amount of cheating.

Orbital velocity is ~2200m/s for Kerbin. So if you don't account for drag, your cannon has to accelerate you to that speed. I never seen a KSP cannon that powerful. And even if it existed, I don't think any pieces could take the heat, they would probably burn up.
Now if you DO account for drag, you need way more than just 2200m/s. How to know for sure but it would probably be double... So you need an even more powerful cannon AND you need to be even more heat resistant.

Maybe it would be somewhat less impossible that if the cannon shoot straight up and let the payload do the circularization burn by itself.
Not quite sure how much velocity you would need in that case, probably still in the order of ~2000m/s with drag... But then you need to carry a lot of fuel with you, so definitely not an easy challenge.

 

[Palaceviking]

Challenge accepted. 

[Clancy]

I thought at first this might be possible with a small capsule sitting on top of a few Kickbacks ganged together and pointed with the fiery end up. You would have to turn on indestructible parts and no heat damage of course, but maybe it could be done?

Then I did some calculations:

Assume small capsule includes Mk1 Command Pod, Spark Engine with enough fuel to circularize, parachute, nose cone, heat shield etc. That's like 2.5t.

I'm not sure how the thrust pressure of the boosters falls off over distance, but let's assume that it falls off linearly from the max thrust (590kN for Kickbacks) to zero at 25m away. (chime in anyone who knows the real values) That gives F(x)=F0(1-x/25)  since a=F/m  a(x)=F0/m(1-x/25)

Blahblahblah-algebra-calculus-spreadsheets means you would need a base thrust of 400,000kN or 678 Kickbacks together.

So, not very practical. I'd still like to see what happens if you hacked the Booster to increase the thrust until it worked.

You could also probably use a fairing and a command seat to make a lighter pod. Or a probe core I suppose.

[sdj64]

7 hours ago, Clancy said:

I thought at first this might be possible with a small capsule sitting on top of a few Kickbacks ganged together and pointed with the fiery end up. You would have to turn on indestructible parts and no heat damage of course, but maybe it could be done?

Then I did some calculations:

Assume small capsule includes Mk1 Command Pod, Spark Engine with enough fuel to circularize, parachute, nose cone, heat shield etc. That's like 2.5t.

I'm not sure how the thrust pressure of the boosters falls off over distance, but let's assume that it falls off linearly from the max thrust (590kN for Kickbacks) to zero at 25m away. (chime in anyone who knows the real values) That gives F(x)=F0(1-x/25)  since a=F/m  a(x)=F0/m(1-x/25)

Blahblahblah-algebra-calculus-spreadsheets means you would need a base thrust of 400,000kN or 678 Kickbacks together.

So, not very practical. I'd still like to see what happens if you hacked the Booster to increase the thrust until it worked.

You could also probably use a fairing and a command seat to make a lighter pod. Or a probe core I suppose.

I think the thrust pressure drops off sooner, it also might be a quadratic or exponential decay...

Math aside, you're already within reasonable part count limits.  If you tried Mainsails or Rhinos (both around 1500 kN in atmosphere), using your calculation you'd need less than 250.

 

It has been attempted before in KSP, especially on the Mun.  Here's an old video (not mine).  https://www.youtube.com/watch?v=MRcetShcw8Q

 

[steeeal]

On 11/3/2016 at 10:06 AM, wibou7 said:

I don't think it would be possible without heavily modded parts and a good amount of cheating.

Orbital velocity is ~2200m/s for Kerbin. So if you don't account for drag, your cannon has to accelerate you to that speed. I never seen a KSP cannon that powerful. And even if it existed, I don't think any pieces could take the heat, they would probably burn up.
Now if you DO account for drag, you need way more than just 2200m/s. How to know for sure but it would probably be double... So you need an even more powerful cannon AND you need to be even more heat resistant.

Maybe it would be somewhat less impossible that if the cannon shoot straight up and let the payload do the circularization burn by itself.
Not quite sure how much velocity you would need in that case, probably still in the order of ~2000m/s with drag... But then you need to carry a lot of fuel with you, so definitely not an easy challenge.

 

KSA "Legtillery" spike over 2km/s but drag slows it down

[SR]

Is it possible to launch your self into orbit with a cannon?

Don't you need to perform a circularisation burn?

[nascarlaser1]

Are we talking about fireing your self from Kerbin into orbit?? or from minimus?

Minimus is easily done and has been done many times by many people.

Kerbin..... hmmm.....

Time to find out!!!