Altitude is the easy part, relatively speaking. Getting the speed for LEO is the hard part. The GoFast rocket you linked to has demonstrated up to 4,200MPH. Low earth orbit requires about 17,000MPH.
That factor of ~4 requires massively larger rockets, because the rocket equation is cruel. Each incremental increase in final speed requires an exponential (actually using this word correctly, for once) increase in the amount of fuel. Fuel in return requires more hardware like tanks and engines, which means yet more fuel is required, etc.
Edit: using RP-1 as the fuel in a single stage, getting to 4,200MPH requires that 45% of your total rocket mass be fuel at launch. Getting to LEO requires 94% of the mass to be fuel.
The difference in ISP between a liquid-fueled rocket (say 450s for LH2/LO2, 350s for RP1/LO2) and solid propellant (250s) makes a huge difference to your prop fraction. To get, say 8km/s delta-v, just plug it into the rocket equation:
LH2/LO2: 6.1 initial/final mass. RP1/LO2: 10.3 solids: 26
Staging can help this a bit, but the basic fact remains. It's very difficult to get useful payload to orbit with solids.
Math is done with numbers, so let me give you actual numbers. You can double-check these against https://en.wikipedia.org/wiki/Orbital_speed#Tangential_veloc....
Standing on the surface of the Earth your potential energy relative to infinity is −62.6 MJ/kg. If you were standing still 160 km up, you've added roughly 1.6 MJ/kg. (You climbed 160,000 meters against a force of 9.8 Newtons per meter.)
To then go into orbit you have to add a sideways velocity of about 7800 m/s. Apply the famous kinetic energy = 0.5mv^2 and going into orbit requires 30.4 MJ/kg of energy. That's 19x more energy than is required to get to altitude!
But it gets worse! If you're going to go into orbit, you need to think about getting down. Going up we go straight up out of the air and then add sideways velocity. Going down we let the atmosphere do most of the work of slowing us down. But in order to survive that you need a much more rugged device with a heavy heat shield. You're now both doing more work per mass lifted AND you're lifting more mass!
But we're not done with the bad news. A fundamental fact about rockets is that you have to lift the fuel you use later in the launch. That means that as you're increasing the final velocity you're getting an ever-decreasing ratio of energy expended to useful kinetic energy for your payload.
Put it all together and actual rocket scientists have told me that it is about 100x easier to get to orbital altitude than it is to actually get into orbit.
That said, LEO is the half-way point. Getting into LEO takes about as much energy as it does to launch from LEO entirely out of Earth's orbit.
It needs to go 4 times faster, and no, a 20% larger rocket won't cut it. 20000% larger by mass would be more like it. It also needs a 2nd stage burning liquid propellant with high specific impulse which is way, way harder to build than a dumb solid propellant rocket.
Noone (not even governments) has been able to send a single stage rocket to orbit.
Also 20000% larger by mass? want to be a bit more serious? if you scale this rocket by 35-40% you get to about the size of the first stage of the Shavit solid fuel space launcher which is a commercial space launcher.
You do understand how scaling works on 3 dimensional objects right?
The GoFast Rocket weighs 350kg. Scaling it by 35% (1.35 ^ 3) would make it weigh 861kg. The rocket you mentioned weighs between 30 and 70 _tons_.
I'm not sure you understand how anything works.
Based on my previous conversations with this guy, this seems to be a recurring pattern. I do hope that he's using these conversations to recognize and fill in the holes in his knowledge. :)
Edit: I see Shavit can also launch in a three stage configuration. My overall point remains.