I just always assumed to achieve higher speeds in the universe you needed to be smaller and more aerodynamic. The Lockheed Blackbird is the fastest fighter jet we have and it goes only 2000mph. This fighter jet seems like it would be more aerodynamic than a rocket ship.
What is special about the rocket ships that allow them to achieve 25,000mph without being disintegrated when leaving the atmosphere and achieving escape velocity to go into space?
Any help would be greatly appreciated.
In: 3
By the time a rocket reaches those speeds, it’s above the atmosphere. The higher you go, the thinner the air gets, until you’re not in the air anymore.
Supersonic airplanes still need to be in the atmosphere. They require airflow over their wing/body in order to fly.
The Blackbird (technically not a fighter jet, it never carried weapons and the SR designation specifically stands for strategic reconnaissance) specifically stays in the atmosphere. Atmosphere is thick when it comes to high speeds. The Blackbird’s engines need air to work. It “only” went to about 85,000ft/16miles in altitude.
Rockets on the other hand, specifically are meant to leave the atmosphere. Rockets bring the oxygen they burn with them in the form of oxidizer. This allows them to launch higher than the atmosphere. At 40,000ft-ish the Artemis rocket is “only” going about 1,000mph. Which isn’t outlandish. The crazy orbital speeds only happen far out of the atmosphere.
The biggest difference is between a Jet engine and a Rocket engine. A jet engine burns regular old aviation fuel (which is very similar to diesel fuel) combined with air it has to scoop from the atmosphere.
Rocket fuel ignites an explosive and requires no air input, they just contain that explosion and eject it out the nozzle. That can produce a lot more thrust than a jet, and without needing air can continue to provide that thrust once they have left the atmosphere. So most of the speed of space craft is gained once the air resistance of the atmosphere is negligible. Jet engines need the air so can never get to that point.
also you seem to have a misconception of what escape velocity is. You do not need to achieve escape velocity to leave the atmosphere. In fact the ISS is sitting there orbiting earth at well below escape velocity. escape velocity is the speed at which the strength of a bodies gravitational pull (earth in this case) is not sufficient to ever pull you back down. In the case of our solar system once you achieve earth escape velocity you’ll no longer be in orbit around earth and will instead get pulled into orbit around the sun.
The ISS is orbiting at about 17,000mph escape velocity is 25,000mph
What’s special is the type and amount of fuel. Notice a crew capsule of a rocket is a tiny room on top of a 10 story column of fuel. All that fuel (and it burns more powefully and quicker than normal fuel) is required to get the small payload to space. You may remember the Space Suttle needed extra fuel tanks because it was much more than a tiny room (but still small by airplane standards).
Airplanes are horizontal and designed to fly carrying things point to point EG LAX-LHR. Rockets are vertical and 90% of the mass of the rocket is to elevate the comparatively small load of 400KG to space. As the rocket increases in elevation there is less air resistance and so the aerodynamic shape matters less
In terms of the universe none of these vehicles are close to getting to 90% of the speed of light (269M m/s) Once you leave Earth’s atmosphere aerodynamic considerations are irrelevant.