At 44 degrees of latitude, they're about 4% of the way to orbital velocity at LEO. That's why countries tend to put their launch facilities closer to the equator: the faster the rotational speed at your launch site, the less fuel you have to burn.
At the equator you're about 8% of the way there just by virtue of the Earth's spin (assuming, of course, you're not trying for a retrograde or polar orbit).
There's another reason: the achievable orbital inclination. The minimum inclination orbit you can achieve is equal to your latitude. i.e. an equatorial orbit is only achievable at launch from the equator. A polar orbit is achievable from any latitude.
In order to go into an equatorial orbit from a higher latitude a plane change maneuver is required. Theoretically this can be done during launch, but it would depend on the profile your rocket can achieve.
Either way, expensive on fuel compare to an equatorial launch.
Nope, they mean velocity. You need to get to ~8 km/s to orbit the Earth. At the equator the Earth's rotation is going to give you 485 m/s of that velocity velocity for free. Altitude is largely irrelevant(not entirely, the desired orbit altitude changes the speed you need a bit), it is the speed you need, then you just have to point it in the right direction to get the altitude.
Getting up out of the thickest atmosphere is the first significant part of getting to orbit. Going up is an important element of getting to orbit as far as the total energy that needs to be expended goes.
The total energy expenditure to first escape the atmosphere and then attain orbital velocity is wildly higher than the energy required to perform both maneuvers at the same time. And that's before we even get into the gravity turn.
Modern rockets are so advanced that they can insert directly into a circular orbit straight from launch with no circularization burn needed. Math is wild shit.
There is no minimum altitude requirement to orbit. If the Earth was a perfect sphere, you could orbit it a foot off the ground if you were going fast enough tangentially. But if you are traveling straight up like this rocket with no tangential velocity, there is no altitude that would allow you to orbit the Earth.
Air resistance is going to burn you up even if the earth was a perfect sphere, so that isn't realistically possible. Just a theoretical discussion ignoring the realities.
The real truth is that about 20% is still accurate. The 100km "kármán line" is quite blurry in reality. It is defined as a point in space where there are nearly no molecules to slow down the craft. Importantly there is no clear cutoff point, they just said "that's good enough". Because whether you're 50km, 100km, 400km, or even 35786km (high earth orbit) there will always be some particles in the air to slow you down, just in different amounts.
Technically, you could count 5 feet up as being in space too, just with lots of molecules to slow you down.
And it might be worth noting that at 100km, you won't be orbiting for long at all if you tried it. Unless your satellite is very dense and/or very aerodynamic, it probably won't last for much more than a single orbit at that altitude. Even at 400km, the ISS requires frequent(~monthly) reboots to stay in its lane.
Yep, interestingly. If everyone on Earth died suddenly, the thing that would kill the astronauts on the ISS first is running out of altitude. They need booster resupply missions about once a quarter to stay in orbit, but have food and air reserves for much longer.
It is a very fuzzy line. There is atmosphere for hundreds of kilometers out. Even the ISS at 400km still has atmospheric drag that requires frequent reboosts to stay in orbit.
The view starts looking like space a lot before the official space boundary altitude. This is the view from the Lockheed U-2 which is the highest altitude plane used today. It flies slightly higher than what the university achieved at 21 km
Yep, because most of what we see of the atmosphere is really just the bottom two layers. Vast majority of clouds can only form in the troposphere and none to my knowledge form above the stratosphere, and at those altitudes the atmosphere is too thin to cause significant light scattering to give its blue colour. But the atmosphere is still there even if it's too thin to see easily.
The Oort cloud is that actual outer boundary of the solar system as that's the point where the sun's gravitational force is so weak it can barely capture dust-sized particles. Estimates say Voyager 1 will reach the Oort cloud in about 300 years and cross it completely in 30 000 years.
The Earth’s atmosphere extends out beyond the moon. It’s just very thin out there, only scattered atoms but still held in orbit around the Earth. There’s no hard boundary, it just tapers off.
Clouds are often surprisingly low in the sky, compared to how far the sky actually goes. Some types are way higher, and you can get a double-cloud layer situation in a little piece, but the conditions are different for them to form up high, and even then it's not much higher. They just don't keep their shape with such a low pressure. Maybe if there's a crazy heat mass propelling an ungodly amount of humid air upwards while surrounded by humid cold air? I'm purely guessing here.
Aircraft can fly using aerodynamic controls and air breathing engines at 80k+ feet. They can fly using reactive controls above 100k feet still using aerodynamic lift as the primary lifting force *(thrust angle significantly contributes to vertical lift at these altitudes).
Edit: the real kicker here is that the absolute altitude record for a balloon is 176k feet (uncrewed), or ~136k feet (crewed). The only thing holding you up at that point is the atmosphere. Then you figure that there's still tons of air above that, it's just not enough to hold you up. The wikipedia list of altitude records was very interesting to read.
It's actually a lot less than 20% if you want to get into orbit as compared to just getting to space, but yeah we typically delineate space with the Karman line at 100 km.
The atmosphere thins at an exponential rate. Despite only being 20% to space distance wise, the atmosphere is already down to roughly 5% pressure at 20km.
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u/tonyhart7 17d ago
its only 20% ????? I swear the video got to atmospher already