During ascent, shuttle crew members are pressed into their seats with more than three times the force of gravity. Crew members on the Russian Soyuz endure four times the force of gravity. The Mercury capsules launched by the Atlas booster reached a peak acceleration of 8g (1g = earth gravity) during ascent to orbit, then decelerated during re-entry at loads as high as 7.8g. The Titan rockets launched the Geminis at 7.25g, and the Saturn 5 peaked at 4g. However, the Apollo capsules returning from the Moon re-entered the atmosphere at over 6g.
How does that feel like? How do you thing our little frog will react to the sudden acceleration ?
Materials: a spoon, marbles, books, a towel, a scale.
Sit in a chair by a table and rest your arm on the scale placed on the table just below your shoulder height. Place the marbles on the spoon and hold it in that hand. Read the weight. Now lift the spoonful of marbles up and down about a foot (40 cm) and notice how it feels.
Still holding the spoon and marbles, rest your arm on the scale again. Place the folded towel over your arm as padding. Open the books and stack them, face down, on top of your arm until the weight on the scale is three times the weight of your arm by itself. (For example, if your arm weighs 6 pounds (3 kg), stack books on until the weight is 18 pounds (8 kg).) This is what your arm and the rest of your body would feel like during launch on the space shuttle. Lift the spoonful of marbles up and down. How does it feel now?
Add more books until the scale reads four times the weight of your arm (e.g., 24 pounds (11 kg)). This is what you would feel during launch on the Soyuz. Try raising the spoon and marbles as before. Can you hold them steady? Why do you think engineers put critical abort switches as near the pilots' hands as possible?
The ascent phase of our rocket launch and the deployment of the capsule are short but still, will create significant pressure over the little frogs body. This will affect the circulatory system and the internal organs. It is also important the direction of the high-g force; the human body is considerably more able to survive g-forces that are perpendicular to the spine. As g-forces increases, visual effects include loss of color vision, followed by tunnel vision (where peripheral vision is lost, retaining only the center vision). If g-forces increase further, complete loss of vision will occur, while consciousness remains. These effects are due to a reduction of blood flow to the eyes before blood flow to the brain is lost, because the extra pressure within the eye counters the blood pressure.A further increase in g-forces will cause g-LOC where consciousness is lost.
Watch these two videos to get an idea about how this feels like: