A re-entry is done by a spacecraft returning to Earth from space at high speed that manages slowing down and land in 10 to 30 minutes. The velocity at beginning of a re-entry at top of atmosphere (altitude 120 000 meters) - the re-entry interface - differs considerably depending on where the space craft comes from. It is suggested that a manned spacecraft arrives with speed >21 000 m/s, when coming from planet Mars, >11.000 m/s, when coming from the Moon or only about 8 000 m/s, when coming from Earth Parking Orbit, EPO. Reason for different re-entry velocities is that Earth gravity has accelerated the spacecrafts during different times; weeks for a spacecraft coming from Mars, days for a spacecraft coming from the Moon and hours for a spacecraft trying to descend from a space station in EPO. You must arrive at the starting point of a re-entry at the right time! If you arrive 10 seconds too early or late, you miss the end point - the landing zone - by 80.000 - 210.000 meters! What the change of direction (°/s) is better forgotten.
Assuming that it is possible to steer the spacecraft to arrive at Earth at the correct location, at the right moment, at the right direction at the upper atmosphere in 3D space (it isn't), it is suggested that suddenly a big brake force (!) develops out of nowhere up in the sky which slows down the spacecraft to land in front of a welcome committee with a brass band. It is suggested that this big brake force is due only to contact between the spacecraft and air or atmosphere but it is nonsense.
It cannot happen in reality!
Only brain washed people believe it!
The first re-entry in history after a trip to the Moon was Apollo 8 on December 27, 1968. Apollo 8 was a small spacecraft capsule/command module without toilet. At 139h15m after start (and no visits to the toilet) Apollo 8 was 94 800 kms from Entry Interface 6h30m away. Speed was only 2 650 m/s. 37 minutes later Apollo 8 was 88 900 kms from Entry Interface with speed 2 740 m/s. During the next 6 hrs velocity increased all the time, e.g. 63 minutes later at140h55m - 78 300 kms from Entry Interface - speed 2 926 m/s, 124 minutes later at 142h59m - 56 340 kms from Entry Interface - speed 3 443 m/s, 37 minutes later at 143h36m - 49 000 kms from Entry Interface - speed 3 680 m/s, 37 minutes later at 144h13m - 41 255 kms from Entry Interface - speed 3 993 m/s, 25 minutes later at 144h38m - 35 188 kms from Entry Interface - speed 4 276 m/s, 31 minutes later at 145h09m - 28 254 kms from Entry Interface - speed 4 712 m/s, 23 minutes later at 145h32m - 21 531 kms from Entry Interface - speed 5 265 m/s, 13 minutes later (1 hr 1 m to Entry Interface) at 145h45m - 17 800 kms from Entry Interface - speed 5 588 m/s, 27 minutes later at 146h12m - 9 167 kms from Entry Interface - speed 7 103 m/s. At 146h31m the Service module was dumped (it burnt up in the atmosphere). Command module continued alone at increased speed. Reason why velocity increased and direction turned down to Earth was that Earth gravity accelerated Apollo 8 straight down all the time!
Re-entry Interface at 120 000 m altitude was apparently reached at 146h46m - speed was then 11 040 m/s! Maybe they were above Tokyo at that time? With that speed straight down Apollo 8 would have hit the Ginza after 11 seconds. It didn't happen. Apollo 8 flew off towards Palmyra island in a remote area of the Pacific Ocean (where nobody could watch)!
What happened then, i.e. the real re-entry trajectory from Entry Interface to splash down is not really known. There was a break in communication but at 146h54m - drogue chutes were out at 7 000 m altitude (we are told) (speed estimate 200 m/s?), at 146h55m - chutes were deployed and at 147h00m - splash down - December 27, 1968 at 15.51.42 UTC, pos 8°8'N 165°1' W. Hole in one! Just in front of awaiting navy ships and a brass band playing! The Apollo 8 crew could finally go to the toilet.
How Apollo 8 managed to slow down from 11 040 m/s speed to 0 in 14 minutes has never really been explained. Everyone was so happy that it just happened, so nobody ever asked ... how? Actually no re-entry took place. It was just a Hollywood show! Or a hoax! Willy Low was so happy! Americans believed anything 1968! The US Space Program was a success! Even if it was 100% fakery!
It is suggested that this brake force consists of aerodynamic drag and lift but there is no air at 120.000 m altitude to provide any drag and lift.
Regardless, drag/lift forces are functions of spacecraft shape and flow, velocity and air density, which are changing all the time, i.e. the forces are not constant and so it is impossible to predict the brake trajectory of the re-entry from when the variable drag/lift forces are applied. You have not got a clue, where you will end up! It means that you will start to spin and burn up.
Furthermore it is suggested (already 1966) that a future spacecraft arriving from Mars at 21 000 m/s speed will bounce (LOL) on the top of the atmosphere, skip out and do a second re-entry (terminal control) a little later, i.e. the brake force lifts the spacecraft back into space again at first contact with the atmosphere:
But how do you control and determine such a high speed, skip out re-entry? Can you do it braking or speeding up with a rocket engine?
In order just to prepare a re-entry from EPO you must ensure that you arrive on time at the location to start re-entry at the exact speed/direction. If you are too early or too late to start your re-entry, you must slow down or speed up before to arrive in order not to make a mess of the rest.
It is not easy. It is in fact very difficult. The only way to slow down is to fire your rocket engine. Apollo 11 didn't have any but the Shuttle had:
To adjust re-entry speed at around 8 000 m/s velocity only from EPO costs plenty fuel. Say that your Shuttle arrives at 8.050 m/s speed with kinetic energy 32.401.250 J/kg, but that it should arrive at 7 950 m/s speed and kinetic energy 31.601.250 J/kg to succeed the complete re-entry. The difference in kinetic energy is then 800 000 J/kg.
Have you got the fuel to adjust the speed 100 m/s? The answer is simple.
Konstantin E. Tsiolkovsky has established that the change in velocity, Delta-v, of a spacecraft in vacuum space (no influence of gravity of adjacent planet Earth) is a function of the mass ratio (spacecraft mass before, m0 and after, m1 firing the rocket engine, difference m0 - m1 being the fuel mass ejected as exhaust gas and the exhaust velocity ve of gas leaving the spaceship rocket nozzle.
It means that you need ~2.5% of the spacecraft mass or 2 000 kg of fuel just to slow down 100 m/s or 1.25% of the speed!
If your rocket engine is an old one with ve only 2.800 m/s, then ln(m0/m1) = 0.035 and m0/m1 is about 1.03636!
It means that you need ~3.6% of the spacecraft mass or 2 800 kg of fuel just to slow down 100 m/s!
And you have to fire the rocket engine in exactly the right direction! Otherwise you brake out of correct direction! And will miss the target.
Let's face it. You cannot do it. You cannot carry the fuel required! You cannot aim the brake force in the right direction.
How Apollo 11 without any rocket engine aboard managed to arrive at the re-entry start point in the upper atmosphere at the right time/speed/direction in 1969 is a mystery. Or not! It was all fantasy!
All re-entries since 1961 are hoaxes! You are going too fast and do not know your speeds, positions and directions at any moment and cannot adjust anything, as you do not have the means to do it.
The re-entry was an integral part of the 1957-1991 US/USSR fake 'space race', i.e. simple propaganda. The Russians just said it was dead easy and the Americans agreed. But it was and is impossible.
Today 2018 it should be patently obvious to any intelligent person that the 'space race' was since day one in the 1950's - and still to this day - nothing but a silly TV 'reality show' and, undoubtedly, a very effective one. It was a brilliant idea on the part of the US (Hollywood?) scriptwriters to have the 'evil Russian communists' being cast as the first 'conquerors of space' and the Russians played along. All Russian cosmonauts were and are actors - like the American ones! No one was in space!
Go to E!