Gargamel

Catapults do not build up g's over time. The g's are over a very short span of time when the arm is released. For any catapult ever built, it would be a second or two at most. The structure is under very high stress as the spring is loaded though. But those aren't the issues with a catapult capable of launching to orbit. A catapult launches it payload when the arm comes to a very abrupt stop. In order to have the velocity required to reach orbit (or altitudes high enough to fire the second stage), you either need to move the arm very very fast, or make it very very long. The problem with very fast is stopping it. The forces involved with stopping an arm going this fast would be catastrophic at best. If we make the arm longer, we now encounter a couple more problems. First off, keeping an arm this long rigid is problematic. If we can design an arm rigid enough to survive the initial acceleration, then we also have to stop it. The traditional design has it hitting a single point to arrest the movement. In this case, that would mean we have this immense momentum hitting a single point, and the arm would snap. So perhaps we build a gigantic structure to distribute the load of stopping. Very impractical. So let's switch the launch mechanism to like one on a trebuchet, where it is released at a certain angle. We still have to arrest the arm eventually. Letting it hit the ground would be as catastrophic as hitting a stop. So.... why don't we just elevate the axle of the arm so that after launching, it can just spin freely? Then why do we need the instant acceleration, when it is has unlimited room to spin up to speed? Let's just attach it to a motor to gradually speed it up and then slow it down. And....... we have SpinLaunch. SpinLaunch is a catapult, just a few design iterations along. The same thought process can be applied to a trebuchet. There's a reason trebuchets are more efficient than a catapult, mainly because they throw farther and are less self destructive, but they tend to be far more massive. Instead of building a massive structure, we can just simplify it down to another SpinLaunch. I think that size estimate is quite low, by a couple orders of magnitude at best. As you mention, the projectile has to reach hypersonic speeds, and as you mention, to get within even sci-fi based materials, the width of our crossbow would probably need to be several dozen kilometers across.

A ballista is merely a large crossbow.

Honestly, I don’t see this being a thing. It’s a kinetic launcher, in the same vein as a Spinlaunch or cannon. You’d have to overcome the same flight issues as those. And those options are drastically more practical than a giant crossbow. If you have mastered the engineering challenges that a giant crossbow presents, of launching something to orbit using tension and elasticity of materials........ then it would be far more efficient to build a space elevator with those same technologies.

Do we know what flight path CRS 24 is scheduled to take?

Hey congrats on the release @JackATac, and welcome to the forums! As per our Add-on Posting rules (Found at the top of this sub forum), we ask that you include a proper license here in the thread on and in the downloadable.

Sure can!

That’s exactly why people don’t do it. The amount of effort required to hit that limit should have set off alarm bells that it wasn’t a very good idea. The limit doesn’t need changed

And we ask that you kindly not do that again.

Add-on Related Question moved to Add-On Discussion.

His Google fu isn’t nearly as good. He’s been trying to figure out a way to ship a live lobster from the US. Thanks. This will work nicely.

Serious question I’m asking for a friend.... no really. If one wished to ship / have delivered lobster to an individual in Thailand, what would be the best option?

Moved to add on discussion.

@starsfan69 Your question has been merged into the MechJeb Mod thread.

apparently it’s too big.

Moved to add-on Development

Booked my hotel in Cocoa Beach with plenty of time to see CRS-24 plus some time for scrubs. I have time to squeeze in a Huntsville stop on the way down. Along with any other info on the region: 1) is the Huntsville facility worth stopping at if I’m already planning on going to the cape that week? 2) Where is the facility relative to Huntsville? 3) anything else I should consider?

Just booked my hotel to go watch CRS-24 in person. Because the editor is giving me fits:. make sure you give home reward for catching something. Dogs prey reflex will cause them long term stress if they don’t get rewarded for catching something.

Welcome aboard @opaugust201. Your post has been merged into the Welcome thread.

Moved to Technical Support. Are you using the same version of KSP that the old machine was running?

Overlapping threads have been merged.

This thread has been moved to Science and Spaceflight.

Some overlapping threads have been merged. And.... boars? Ahem... Back on topic guys....

Just to butt in to the DART mission here.... CRS-24. That should be an almost guaranteed non scrub, weather aside, with an instant window? Also, would that be a barge or pad landing for the booster? Asking for a friend myself who might be going down there.

@Codraroll excellent!