1: you need to launch something at 8200m/s to get into low earth orbit. That’s not counting air resistance, or equatorial benefits, so let’s ignore both.
2: gravity acceleration is 10 meters per per second. So 5 time gravity is 50 meters per second per second (50m/s^2)
3: to launch something into orbit, from a railgun at 5g, you need to accelerate for 8200/50=164 seconds. Your average speed will be 4100m/s for 164 seconds.
4: a 5g orbital railgun will have to be 4100x164=672km long. And probably still crush any sattelite you want to put on it.
The electronics within an artillery shell can survive tens of thousands of gees just fine. The Sprint missile accelerates at a hundred g. A launch system will only need to be several kilometers long.
People will never be launched this way for sure. As for scientific equipment, that’s a very nebulous term. Almost all solid state hardware can be launched this way. The efficiency of the launch system will allow for heavier, more robust payloads. Even a JWST can be modified for launch in this manner.
China has always been about weird projects on a large scale. For one there’s the desire to show off its greatness and second, the incompetent or fearful mid-level management unable or unwilling to say no. So every once in a while, a project gets announced, gets made shoddily, embarrassment ensues and heads roll.
And the thing is, we see it happen in the US all the time. That company that promised launching a rocket every other day is a recent example.
the gravitaitonal constant is only constant at one specific height in the gravitaitonal field. But the gravitaitonal force is reducing, the further away from earth you get. So what you actually have to do is calculate U1 = -GMm/r1 for the LEO and U2 = -GMm/r2 for surface level. leaving out the objects mass already you get as difference
(U1-U2)/m = 6.67e-11 x 5.97e24 x (1/6,73e6-1/8,73e6) = 13,555 Now that is your specific energy from the starting velocity = 1/2 v² from the kinetic energy. So at ground level you actually need 5,206 m/s ignoring air friction.
Also your length of the railgun exceeds the atmosphere, so not only for the friction, but also for the distance to earth you will need much less speed at the end of that railgun. Furthermore g will get less as it gets higher, so you can accelerate faster towards the end of it.
I’m not claiming the concept is viable by default, but your calculation is not including crucial aspects of how gravitaitonal force changes in a gravitaitonal field.
1: you need to launch something at 8200m/s to get into low earth orbit. That’s not counting air resistance, or equatorial benefits, so let’s ignore both.
2: gravity acceleration is 10 meters per per second. So 5 time gravity is 50 meters per second per second (50m/s^2)
3: to launch something into orbit, from a railgun at 5g, you need to accelerate for 8200/50=164 seconds. Your average speed will be 4100m/s for 164 seconds.
4: a 5g orbital railgun will have to be 4100x164=672km long. And probably still crush any sattelite you want to put on it.
The electronics within an artillery shell can survive tens of thousands of gees just fine. The Sprint missile accelerates at a hundred g. A launch system will only need to be several kilometers long.
Neither artillery shells nor missiles tend to be packed full of fragile scientific instruments, solar panels, people, or liquids.
If your goal is only to launch solid cubesats, this might work, otherwise it’s nonsense.
People will never be launched this way for sure. As for scientific equipment, that’s a very nebulous term. Almost all solid state hardware can be launched this way. The efficiency of the launch system will allow for heavier, more robust payloads. Even a JWST can be modified for launch in this manner.
what do geese have to do with this?
China has always been about weird projects on a large scale. For one there’s the desire to show off its greatness and second, the incompetent or fearful mid-level management unable or unwilling to say no. So every once in a while, a project gets announced, gets made shoddily, embarrassment ensues and heads roll.
And the thing is, we see it happen in the US all the time. That company that promised launching a rocket every other day is a recent example.
Oh, but they’re DEFINITELY doing well. They’re totally on schedule for an unmanned moonlanding in… checks notes… Q1 2024.
How did you calculate 8200 m/s?
the gravitaitonal constant is only constant at one specific height in the gravitaitonal field. But the gravitaitonal force is reducing, the further away from earth you get. So what you actually have to do is calculate U1 = -GMm/r1 for the LEO and U2 = -GMm/r2 for surface level. leaving out the objects mass already you get as difference
(U1-U2)/m = 6.67e-11 x 5.97e24 x (1/6,73e6-1/8,73e6) = 13,555 Now that is your specific energy from the starting velocity = 1/2 v² from the kinetic energy. So at ground level you actually need 5,206 m/s ignoring air friction.
Also your length of the railgun exceeds the atmosphere, so not only for the friction, but also for the distance to earth you will need much less speed at the end of that railgun. Furthermore g will get less as it gets higher, so you can accelerate faster towards the end of it.
http://hyperphysics.phy-astr.gsu.edu/hbase/gpot.html
I’m not claiming the concept is viable by default, but your calculation is not including crucial aspects of how gravitaitonal force changes in a gravitaitonal field.
I looked at a delta-v chart, which mostly list 9000-10000 for 250km orbits. I subtracted 10% from the one on Wikipedia for an absolute minimum.
That rather speaks against the concept, wouldn’t you say?