How they bring down astronauts safely from the space to the ground?
Reentry problem does not explain how much reverse force that the reentry capsule has to exert within few minutes of entry to thick atmosphere.
http://science.jrank.org/pages/6344/...solutions.html
http://www.universetoday.com/85322/low-earth-orbit/Perhaps the most serious single problem encountered during reentry is the heat that develops as the spacecraft returns to the earth's atmosphere. Friction between vehicle and air produces temperatures that exceed 3,000°F (1,700°C). Most metals and alloys would melt or fail at these temperatures. To deal with this problem, spacecraft designers have developed a class of materials known as ablators that absorb and then radiate large amounts of heat in brief periods of time. Ablators have been made out of a variety of materials, including phenolic resins, epoxy compounds, and silicone rubbers.
Read more: Manned Spacecraft - Reentry Problems And Solutions - Earth, York, —the, and Moon - JRank Articles http://science.jrank.org/pages/6344/...#ixzz48rFJKtT9
https://en.wikipedia.org/wiki/Intern..._Space_StationLow Earth Orbit is a region that includes Earth at Sea Level and up to 2000 kilometers above sea level. This region is close enough for a panoramic view of the Earth but just far enough that most space craft can stay in orbit without being pulled down to the surface by Earth’s gravitational field. However satellites at this altitude have to move at extraordinary speeds to partially escape the pull of Earth’s gravity. A satellite in low Earth orbit travels at a mean velocity of 26,000 to 27,000 km per hour or 17,000 miles per hour
Suppose the reentry capsule with rocket engine departs from the ISS in 27,000 km/h at 400 km height. It falls towards the Earth at 7,500 m/s and requires to slow down the capsule below 16.7 m/s (60 km/h) within 54 seconds for the safety of crews inside capsule.It travels at an average speed of 27,724 kilometres per hour (17,227 mph), and completes 15.54 orbits per day (93 minutes per orbit)
Between 400 km to 40 km of height, air density is near vacuum ( 0.03996 at 40 km height). And the gravity of Earth constantly pulls it 9.8 m/s^2.
Average deceleration of the capsule = (7,500.00 - 16.7) / 54 = 138 m/s^2
Total deceleration force the capsule requires is 138 m/s^2 + 9.8 m/s^2 = 147.8 m/s^2
Let's convert it to unit g force (9.8 m/s^2). 147.8 / 9.8 = 15.08 G.
High acceleration over 9g is lethal. I doubt human body can't handle over 10g.
To me rocket propulsion is such absurd, primitive technology that space travel is not feasible. Rocket only provides one way trip, waste huge amount of resources too. Unless NASA or whatever secret space program uses non-conventional propulsion system, space exploration as we know is simply a day dream.
Since I convinced myself that 1969's Apollo Moon landing was a fake event, space exploration becomes elaborated scam that gullible public takes as is. Who cares anyway. USA, former Russia back then, multinational space organization nowadays. China sent a probe to the Moon? Which country will go back to the Moon? It's plain silly stuff.
Mainstream astronomers haven't solved N-body problem. Orbital motion of planets in solar system. The stupid thing is all they believe in gravitational constant G is fixed value. And they have developed powerful computer simulation hopelessly. But the real problem is the G value changes on Earth depending on height or location of measurement. Astronomers try to ignore it because G has to be constant in their dogmatic framework. I guess their pride hurts as soon as they admit serious flaws in fundamental laws in physics.
Rocket propulsion is rubbish.
Speed of light is too slow as communication.
Don't know how to predict or calculate trajectory of planets with acceptable precision for space travel.
Flat Earth believers are gaining momentum too.![]()




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