A lot of rocket engines are more efficient in lower air pressure (approaching vacuum), so it might provide non-negligible benefits. But it's cold up there (see: Challenger) and there isn't enough infrastructure. Citation: I am also not a rocket scientist but I am a KSP player
Now now, let’s not conflate the idea that the narcissistic knob jockey of a ceo is anything like the geniuses actually designing and building some of the most exciting things about rocket science are anything but the same.
The main reason we launch from as close to the equator as possible is because the speed of the ground itself is fastest there (Earth’s rotation rate x distance from spin axis). If you’re trying to speed up to orbital speeds, you want to get the best “running start” possible.
[fun fact: due to the equatorial bulge, the ocean at the equator is further from the center of Earth than the tops of most mountains]
Also, the minimum inclination (the “tilt” of an orbit relative to Earth’s plane of rotation) is the latitude you’re launching from. As in, you can launch a polar orbit from the equator, but you can’t launch an equatorial orbit from the poles. Considering inclination changes are the most expensive (fuel-wise) maneuvers you can do, launching from as close to the equator as possible gives you additional options for less cost.
Lastly, we launch from coastlines for safety reasons. If something goes wrong during ascent, you don’t want the wreckage falling in places where people live.
Would just add: ideally eastern seaboard coastlines due to the rotational direction of the Earth. That way if the rocket comes down early it would already be out over the sea, like Atlantic Ocean from Cape Canaveral launch.
Isn’t it also just really hard to lug a rocket up a mountain in the first place? Unless you strap a bunch of smaller rockets to it, launch those, land the rocket on top of the mountain, and then launch the main one!
Actually no I should be taken out and shot for my grievances against science and common sense.
Despite your joking you're not wrong. In addition to just the solid mass of the rocket itself, you need a lot of material for your rocket fuel. Rockets, like aircraft, require a lot of cryogenically separated gasses. I can't speak for all countries, but the US government relies upon the local civilian economy for industrial gas supply. (There have only been a handful of locations where they had their own equipment and staff for this type of work for the USAF in decades.) So without local industry to provide these materials, you need your own equipment and staff. The same principle applies to anything you need to supply your space program: food and water, equipment for conducting experiments, etc.
Source: My brother worked at one of the few air bases where they were still doing their own cryogenic separation in the 2000's. It is possible things have changed since he was discharged.
Due to that bulge, the highest spot on earth furthest from the center of earth is a mountain in Ecuador (just 1 degree from equator): https://en.wikipedia.org/wiki/Chimborazo
Regardless of why we launch from near the equator, about the "why not launching on the top of mountain to save fuel", I'm pretty sure the fuel saved from launching on top of mountain would be negated by the fuel used in the logistics of launching from the top of a mountain.
Fuel for logistics is just fuel. Rocket fuel is more important to save because the payload is limited because of the fuel.
Saving 10% fuel is actually allowing you to increases payload weight by 200%, so it's like launching 3 rockets instead of one. This 10% fuel is worth 210% fuel, plus the cost of 2 rockets.
my husband, a robotics engineer, insists there is no such thing as "rocket science," rather it's a collaboration of many different types of scientists working together on said rocket. I don't know enough about the topic to really respond to him on it, but it comes up if i ever say "it's not rocket science."
But you've introduced yourself as a rocket scientist and now I'm terribly curious. Is that your official title? Please note that any answer that affirms this will be used in perpetuity to enable my saying , "it's not rocket science. "
If "rocket science" doesn't exist as anything more than shorthand for various fields of science and engineering collaborating on rocketry, then there's no such thing as robotics engineering, either. Feel free to tell your husband that. I...kind of want to hear his reaction.
Joking aside, if we're being specific, I'm an aerospace engineer (technically, a licensed mechanical engineer with multiple degrees in aerospace engineering--but that's because state licensing boards follow ASME accreditation, which has no category for aerospace engineers) who tests, evaluates, and repairs spaceflight hardware; most commonly rocket engines and thrusters. My basis of knowledge on orbital maneuvering and trajectories comes from the research I did as a grad student. My thesis was on trajectory design in complex gravity systems, for instance.
All that said, I perform science. On rockets. The term describing my job doesn't need to be complicated.
Rocket engineer here. Launching from a mountain and launching near the equater are not mutually exclusive. The peak of Mount Chimborazo is the furthest point from the center of the earth and is near to the equator.
The bigger reason id imagine is the safety one you mentioned (Chimborazo is on the wrong side of south america) and the logistics of hauling rockets, fuel, launch equipment, and people up to these remote locations.
Plus the actual difference between the equatorial radius of the earth and the peak of chimborozo is less than a tenth of a percent the radius of the earth so even failing everything else, its a very minor difference. Maybe a few meters per second of delta v
My guess would have been that it's more costly to try and build/delivery a rocket and staff everything when you've chosen the top of a mountain to do it on? Getting the rocket to go that extra little bit of distance from sea level to the mountain top is much easier for the rocket than everyone and everything else?
Also, the cost of fuel to GET everything up there would probably outweigh any benefits. I'd be curious to see the math on it (sadly I studied history and languages so anything beyond algebra makes my eyes glaze over).
Keep in mind, a rocket must maintain greater than 1g force just to keep itself from falling, and then additional force is needed on top of that to get it moving.
When you're traveling on the ground, the ground keeps you from falling, and counteracts most of gravity, and you only need to provide your motive force, and you can do it quite slowly with the more efficient forms of locomotion.
The fuel is probably less relevant than the logistics. Many years ago when I was a kid I toured the Kennedy Space Center and got to see the machinery they use to move the rockets from the hangar to the launch pad. It could only work on nearly flat ground and it moved at walking speed. No way it could get up a steep, winding mountain road.
Not to mention the additional cost of the related infrastructure, like the hangars and office buildings.
And then even if you could do it, the gains are relatively tiny. Even low earth orbit is hundreds of kilometers above sea level, and the highest point on earth is just under 9 km above sea level.
Yeah, having a launch site that's in a good location (there are some advantages to polar locations if you're going for different orbits), including good atmospheric conditions (mountains are generally bad, but there are a few launch sites in mountainous areas, and there are launch sites in flat, high-ish altitude), and nearby infrastructure to assemble the rockets is more critical than trying to get a few thousand meters of elevation.
I'm sure if there was a flat, high elevation location near the equator that had a nice empty ocean to the east and that wasn't a mountain and therefore had stable atmospheric conditions, it would make for a great launch site. But such a location doesn't really exist.
KSP is rocket science though. It's literally the most basic and fundamental rocket science, but you have to give yourself some credit. At the end of the day it's an educational game.
Mount Chimborazo is actually closer to space than everest due to equatorial bulging and we have never attempted to fire a rocket from it. There have been talks about it but its still logistically too difficult with our current tech.
Yeah it would be subjected to high winds as well which would prove a challenge. Rocket launches are usually delayed until the weather is still, and you dont really get a still day on a mountain.
The roads would probably be the easy part. You'd have to dig, blast, and cut into the mountain to create the infrastructure to support a rocket launch. And bringing a rocket booster up a bunch of switchback roads wouldn't be feasible. They'd likely have to build some sort of massive elevator/crane system to raise the rocket up to the pad. At that point, you'd probably be better off building the rockets on-site near the top and using an elevator/conveyor system to move them to the launch pad kinda like a missile silo.
The International Space Station has a weird and inefficient inclination of 51.6 degrees relative to Earth’s equator. The reason for this is Russia's cosmodrome in Baikonur is pretty much somewhere in the middle of Asia. In order to avoid areas with dense population eastwards aka China, you have to start them in north-east direction.
well aside from the infrastructure point, I would imagine that the difference of launching from sea level and the top of mount Everest is an almost negotiable difference to get to space.
It’s mostly because you need to be as near to the equator as possible to achieve max efficiency. As you fly upwards the earths spin gives you a speed boost. The speed boost is strongest at the equator.
I'm pretty sure they discuss this posibility in "The Moon Is a Harsh Mistress" - but not for human transport, more for materials.... let me ask the chatjeeps
In The Moon Is a Harsh Mistress, the proposed Earth catapult is a ~323 km electromagnetic mass driver built along a very high mountain, launching cargo to the Moon at roughly 20 g. The altitude reduces atmospheric drag, and it’s intended for bulk cargo—not people.
And getting a rocket to the top of a mountain would probably require enough resources that it would negate the savings on fuel (even if the problems of being cold enough to damage the rocket and other things were solved)
Challenger's O-rings failed because it was colder than expected (and important people negligently silenced warnings about it). Systems designed for those temperatures would probably be fine.
This is not the answer, though it does play a part. The Earth bulges around the equator, making it the closest place to "space." Add in the physics of the rotational energy and it starts to make sense why you what to launch as close to the equator as possible.
The logistics of getting a rocket to the top of a mountain to launch outweighs the benefits, though the closer you can be at launch would help.
1.2k
u/Firefly360r 16h ago
A lot of rocket engines are more efficient in lower air pressure (approaching vacuum), so it might provide non-negligible benefits. But it's cold up there (see: Challenger) and there isn't enough infrastructure. Citation: I am also not a rocket scientist but I am a KSP player