Re-entry

[Heiwa]

I have become interested in how to get a space ship back to Earth (or to land on Mars) after an excursion in space, i.e. re-entry. Due to Earth gravity it takes a lot of energy to get the space ship up into space to start with, but it takes no energy at all to get the space ship back to Earth as gravity will just pull it faster and faster, when it is supposed to land. It is like dropping a weight from a plane at say 10 000 meters altitude. It will just drop faster and faster until it hits ground. How can a space ship actually re-enter and land on Earth (or Mars) at end speed 0?

Apollo 11 and the Mars MSL use a heat shield as an only brake, while the Shuttle did acrobatic flying to slow down.

Re-entry has been done many times we are told, so I have made the following table:


The Shuttle is the heaviest space ship - 78 000 kg - managing a re-entry. Apollo 11 had the highest re-entry speed - 11 200 m/s and therefore most kinetic energy (MJ) per mass (kg) - 62.72, but the Shuttle's total kinetic energy to transform into friction and turbulence heat is the biggest - 3 159 (GJ). Those energies would increase the temperature of any space ship and the surrounding >19 000°C due friction!

Manned Apollo 11 and Shuttle do a re-entry in about 30 minutes with a mean deceleration of 0.64-51g and distances travelled in atmosphere are very long 8 000 - 10 000 km (1/4 of the Earth's circumference), while the unmanned MSL does a total re-entry at Mars in 'seven minutes of terror' at mean deceleration 2.15g and travelling only 817 km, which is quite long too.

Apollo 11 and MSL use a heat shield to absorb the kinetic energy as friction and turbulence of the order 200-250 MJ/s, while Shuttle is doing acrobatic flying causing plenty turbulence to absorb 1 755 MJ/s energy.

Little footage exists from the cockpit of a Shuttle during manual (!) re-entry maneuvering (how can you film with deceleration 0.5g during 30 minutes with all crew strapped to their seats and the pilot trying to fly the Shuttle?). Existing footage on Internet seems a joke.

The Shuttle was subject to a mean brake force (due friction and turbulence) of 390 000 N during re-entry or more than 10 times Apollo 11. The MSL mean brake force at Mars was 78 228 N or more than double Apollo 11 and you wonder how it is possible in the thin Mars atmosphere. Can a heat shield produce such big brake forces?

It seems NASA/JPL cannot provide any scientific evidence for it. I have asked them.

The Mars' atmosphere is 100 times less dense than Earth's with a ground pressure 60 times lower, but Mars' atmosphere seems to be able to slow down re-entry for MSL twice quicker than for Apollo 11. NASA/JPL cannot provide any scientific evidence for it either.

I have a distinct feeling that all types of known US space ship re-entry to any planet is a hoax. The US space ships would just burn up like any meteorite.

[Dcopymope]

I have become interested in how to get a space ship back to Earth (or to land on Mars) after an excursion in space, i.e. re-entry. Due to Earth gravity it takes a lot of energy to get the space ship up into space to start with, but it takes no energy at all to get the space ship back to Earth as gravity will just pull it faster and faster, when it is supposed to land. It is like dropping a weight from a plane at say 10 000 meters altitude. It will just drop faster and faster until it hits ground. How can a space ship actually re-enter and land on Earth (or Mars) at end speed 0?

Apollo 11 and the Mars MSL use a heat shield as an only brake, while the Shuttle did acrobatic flying to slow down.

Re-entry has been done many times we are told, so I have made the following table:


The Shuttle is the heaviest space ship - 78 000 kg - managing a re-entry. Apollo 11 had the highest re-entry speed - 11 200 m/s and therefore most kinetic energy (MJ) per mass (kg) - 62.72, but the Shuttle's total kinetic energy to transform into friction heat is the biggest - 3 159 (GJ). Those energies would increase the temperature of any space ship >19 000°C due friction!

Manned Apollo 11 and Shuttle do a re-entry in about 30 minutes with a mean deceleration of 0.64-51g and distances travelled in atmosphere are very long 8 000 - 10 000 km (1/4 of the Earth's circumference), while the unmanned MSL does a total re-entry at Mars in 'seven minutes of terror' at mean deceleration 2.15g and travelling only 817 km, which is quite long too.

Apollo 11 and MSL use a heat shield to absorb the kinetic energy as friction of the order 200-250 MJ/s, while Shuttle is doing acrobatic flying to absorb 1 755 MJ/s energy.

Little footage exists from the cockpit of a Shuttle during manual (!) re-entry maneuvering (how can you film with deceleration 0.5g during 30 minutes with all crew strapped to their seats and the pilot trying to fly the Shuttle?). Existing footage on Internet seems a joke.

The Shuttle was subject to a mean brake force (due friction) of 390 000 N during re-entry or more than 10 times Apollo 11. The MSL mean brake force at Mars was 78 228 N or more than double Apollo 11 and you wonder how it is possible in the thin Mars atmosphere. Can a heat shield produce such big brake forces?

It seems NASA/JPL cannot provide any scientific evidence for it. I have asked them.

The Mars' atmosphere is 100 times less dense than Earth's with a ground pressure 60 times lower, but Mars' atmosphere seems to be able to slow down re-entry for MSL twice quicker than for Apollo 11. NASA/JPL cannot provide any scientific evidence for it either.

I have a distinct feeling that all types of known US space ship re-entry to any planet is a hoax. The US space ships would just burn up like any meteorite.

Like I said before, none of this is going to get anywhere until a documentary is made that would conclusively expose the space program as a hoax, both from the fakery and scientific aspect. If you and others on here are truly confident in this information, then you should all get together somehow and get a documentary made.

[fbenario]

Like I said before, none of this is going to get anywhere until a documentary is made that would conclusively expose the space program as a hoax, both from the fakery and scientific aspect. If you and others on here are truly confident in this information, then you should all get together somehow and get a documentary made.

Dcopy, does this post strike you as supportive of the maths research efforts of other trusted members, trying their best to educate the world, just as you are trying your best?

[Dcopymope]

Like I said before, none of this is going to get anywhere until a documentary is made that would conclusively expose the space program as a hoax, both from the fakery and scientific aspect. If you and others on here are truly confident in this information, then you should all get together somehow and get a documentary made.

Dcopy, does this post strike you as supportive of the maths research efforts of other trusted members, trying their best to educate the world, just as you are trying your best?

Its quite an exaggeration to claim you're educating the world when hardly anybody has even heard of this site, the only place where research of this type is even discussed. You should be asking whether or not this information is being spread at all anywhere beyond this site before claiming to educate anybody. You can stay here and post all this info here as long as you like, NASA will continue conning the world without hindrance. But quite frankly, I'm not even trying to 'educate' the world much about anything anymore, as I personally don't care much for 'the world'. This world can burn in hell for all I care as well anybody that's of it. If you are of the world then you are not of the truth by definition, so its not like spreading this info would make much of a difference anyway. I was really kidding myself.

[Heiwa]

There are at least three companies offering private space travel:

One is Excalibur Almaz, EA, (http://www.excaliburalmaz.com/) :

EA owns four RRV (Reusable Reentry Vehicle) capsules and two large Salyut-Class Spacecraft. The reusable reentry capsules can carry three passengers to Low Earth Orbit (LEO). The two Spacecraft are equivalent to the Russian Mir core or the International Space Station (ISS) Zarya module. EA has developed a plan to dock an RRV to a Salyut-Class Spacecraft in LEO and use the combined spacecraft as a transportation system to the moon, libration points, asteroids and deep space.

Then there is DePrez Travel (http://www.depreztravel.com/galactic.html) promoting somebody we already know.


The third company is Space Adventures (http://www.spaceadventures.com/).

I have evidently asked these companies how they intend to manage a safe re-entry after a space trip and … none of them has been able to reply so far.

There are of course more companies offering private space travel. And I wonder how they get away with it!

[lux]

This is supposed to be footage of the last moments of Shuttle Columbia on re-entry:


full link: http://www.youtube.com/watch?v=aIJiW8d_c68

Starting at about 8:40 there are quick shots intercut with the interior footage showing the outside of the shuttle. Where were the cameras that took these exterior shots? (one might ask)

Looks pretty hokey to me.

[Tufa]

Heiwa, I think that we should not exclude the atmosphere from the discussion. The space-ship will indeed go very hot, but the energy is received by the atmosphere. So there is no time-function to build up temperature. Rather, the temperature will balance between incoming friction forces, emitted energy due to radiation, and emitted energy into the atmosphere. The stored energy in the sheild will be constant, as the sheild temperature will be constant.

Just my thought...

[Heiwa]

This is supposed to be footage of the last moments of Shuttle Columbia on re-entry:


full link: http://www.youtube.com/watch?v=aIJiW8d_c68

Starting at about 8:40 there are quick shots intercut with the interior footage showing the outside of the shuttle. Where were the cameras that took these exterior shots? (one might ask)

Looks pretty hokey to me.

The re-entry takes 30 minutes, while the average deceleration is 0.51g mostly due to acrobatic flying, we are told, trying to slow down the 78 ton Shuttle. Friction does not contribute much. I doubt you can sit and page through some manuals in such conditions ... or chat with landing tower. You must be strapped to your seat, if not you will fly through the wind screen in front of you, because the 390 000 N brake force is applied on the Shuttle outside ... and not on the pilot or passengers inside. That's what seat belts are for.

[Heiwa]

Heiwa, I think that we should not exclude the atmosphere from the discussion. The space-ship will indeed go very hot, but the energy is received by the atmosphere. So there is no time-function to build up temperature. Rather, the temperature will balance between incoming friction forces, emitted energy due to radiation, and emitted energy into the atmosphere. The stored energy in the sheild will be constant, as the sheild temperature will be constant.

Just my thought...

Exactly! Only friction/turbulence between atmosphere and space ship heat shield provides a braking force at re-entry for most space ships. Imaging if your car or motorcycle would rely on that to stop down on ground. Luckily the latter is fitted with brake pads that reduce rotation ot the tyres in contact with ground = good braking unless ground is slippery. In atmosphere it is only friction between air and heat shield that counts. It is evidently very slippery.

[fbenario]

Like I said before, none of this is going to get anywhere until a documentary is made that would conclusively expose the space program as a hoax, both from the fakery and scientific aspect. If you and others on here are truly confident in this information, then you should all get together somehow and get a documentary made.

Dcopy, does this post strike you as supportive of the maths research efforts of other trusted members, trying their best to educate the world, just as you are trying your best?

Its quite an exaggeration to claim you're educating the world when hardly anybody has even heard of this site, the only place where research of this type is even discussed. You should be asking whether or not this information is being spread at all anywhere beyond this site before claiming to educate anybody. You can stay here and post all this info here as long as you like, NASA will continue conning the world without hindrance. But quite frankly, I'm not even trying to 'educate' the world much about anything anymore, as I personally don't care much for 'the world'. This world can burn in hell for all I care as well anybody that's of it. If you are of the world then you are not of the truth by definition, so its not like spreading this info would make much of a difference anyway. I was really kidding myself.

I thought one of the forum's main goals was to educate one person at a time to think for himself, so he no longer automatically believes the shit spoon-fed to him as pablum by his oh-so-beloved and trustworthy gov. press releases and TV/radio news programs, with the result being no more passive acquiescence by him in America's continuing efforts that leave dead folks strewn across the planet.

Although on this, as on everything else, I suppose I could very well be wrong, and you could very well be right. Although I doubt it.

[Fred54]

In atmosphere it is only friction between air and heat shield that counts. It is evidently very slippery.

It is evidently very "sticky" Nice chart Heiwa

[lux]

I find this subject somewhat confusing.

"Speed" is always in relation to something else. A car's speed is in relation to the road it is traveling on. An airplane's speed is in relation to the air it is traveling through (or the ground below it), etc.

What is the speed for these orbital objects in relation to?

Does this speed take into account the rotational speed of the Earth and/or atmosphere?

For, example, if a satellite is said to be in geostationary orbit then its speed in relation to the surface of the Earth would be at or close to zero, wouldn't it? And, the atmosphere is generally considered to rotate with the Earth, no? So, how is its speed measured? Would it require a heat shield to survive re-entry if it simply descended from its geostationary orbit?

[Heiwa]

Speed in space is measured in meter per second .

A geostationary satellite orbits Earth at 24 hrs (in the equatorial plane) and its orbital (tangential) speed (relative Earth) is the distance of the orbit in meter divided by 86 400 seconds (i.e. 24 hrs). As the Earth rotates 360° in that time, the satellite appears fixed relative to a point on Earth Equator but it has in fact made one full trip around the Earth ... like the point on the Equator.

As Earth and satellite also orbit the Sun at another speed the absolute speed of e.g. the satellite relative Sun is the sum of the two speeds, i.e. the speed around Earth + the speed around Sun.

The Sun, Earth and satellite probably also orbits around the center of the Universe at a third speed and you have to add it to get the absolute speed of the satellite. But it is only the speed relative Earth that matters for an observer on Earth.

[lux]

A geostationary satellite orbits Earth at 24 hrs (in the equatorial plane) and its orbital (tangential) speed (relative Earth) is the distance of the orbit in meter divided by 86 400 seconds (i.e. 24 hrs). As the Earth rotates 360° in that time, the satellite appears fixed relative to a point on Earth Equator but it has in fact made one full trip around the Earth ... like the point on the Equator.

But, it's speed relative to any point on Earth is zero, right?

If I can see it directly over my head and it never movies from being directly over my head, it's speed relative to me is zero, no?

[Heiwa]

A geostationary satellite orbits Earth at 24 hrs (in the equatorial plane) and its orbital (tangential) speed (relative Earth) is the distance of the orbit in meter divided by 86 400 seconds (i.e. 24 hrs). As the Earth rotates 360° in that time, the satellite appears fixed relative to a point on Earth Equator but it has in fact made one full trip around the Earth ... like the point on the Equator.

But, it's speed relative to any point on Earth is zero, right?

If I can see it directly over my head and it never movies from being directly over my head, it's speed relative to me is zero, no?

Yes, because you on Earth are also moving at a certain speed due Earth rotating around itself in 24 hrs.
It is like being on a highway in a car trying to overtake another car that then accelerates, so you are doing same speed = relative speed between cars zero.
But relative to ground your speed may be 30 mph or 80 mph, same as the other car.