Sure!

A ground based acceleration on it's own isn't really an option - the speed needed for escape velocity is well into hypersonic speeds so you'd burn up, but launching into a low earth orbit with only small rockets to provide corrections is physically possible. As you mention though, that wouldn't work for astronauts, just cargo.

But a part approach with a ground launch then rockets is absolutely possible to claw back some of the limits from the rocket equation.

I believe there's a company called Spinlaunch who are developing a system like this (not for humans sadly) where the rocket is accelerated by a spinning arm in a vacuum sealed chamber before being launched.

In general, getting objects going fast enough without an enormous launch tube is a bit of an engineering challenge. Also, I guess given we are not in the 50% larger scenario people are happy with rockets.

This idea comes from the rocket equation.

The basic idea of which is this: you want to get some amount of mass into space to do this you need to be going fast enough to get into orbit and to do this you need to burn fuel. Simple enough. If you know how much mass you need to launch you can work out how much fuel you need.

The problem is you have to take that fuel with you in the rocket. That fuel also has mass.

So now you need even more fuel to get that mass of the fuel you need into space as well. And you need even more fuel to account for the mass of that fuel.

Here's the wikipedia article for the rocket equation. Give it a read if you want to see the actual equation and the derivations - it's surprisingly readable.

In any case we can derive an equation for how much fuel we need for any rocket.

What we can also do is look at the equation the other way round. I think I found the article that originated the 50% idea and they explain their reasoning pretty well:

>Let us assume that building a rocket at 96% propellant (4% rocket)... is the practical limit for launch vehicle engineering. Let us also choose hydrogen-oxygen, the most energetic chemical propellant known and currently capable of use in a human rated rocket engine. By plugging these numbers into the rocket equation, we can transform the calculated escape velocity into its equivalent planetary radius. That radius would be about 9680 kilometers (Earth is 6670 km). If our planet was 50% larger in diameter [while maintaining the same density], we would not be able to venture into space, at least using rockets for transport.