Newton would not agree on the first question, nor would anyone knowledgeable in gravity and space, because the Earth’s gravity extends far out even outside its atmosphere. Its strong gravitational and magnetic pull is the reason why we have the moon orbiting Earth, as well as the space debris that is scattered just around the outskirts of the planet.
On the other hand, when circling above the Earth, a spacecraft can sometimes climb no higher than 250 kilometers. At altitudes as low as this, the ship and its occupants are still very much held in the Earth’s grip. Given this fact, why don’t the spacecraft and its pilots feel the pull of gravity, which is the source of weight?
The answer for that has a bit of surprise to offer. For one, an orbiting spacecraft doesn’t actually fly around the Earth; in fact, they fall and continue to do so for days, months, or even years depending on the altitude of their flight. The spaceship moves like a cricket ball that has been hit skyward for six meters, the vehicle will reach its apogee (highest point) no sooner in space, and then it will eventually begin to drop back to the Earth. However, because of its immense power to speed through the atmosphere, the spacecraft never actually reaches the ground. The reason for this is that the Earth below constantly curves its gravity away from it, hence the reason why the spaceship’s circular or elliptical plunge never comes to an end. But why does this flight produce weightlessness for the pilots or occupants of the spacecraft?
The answer is that the sensation of weight that we experience daily is not only due to the pull of gravity but also to our constant resistance to its tug. If you were to remove the supporting ground or the floor beneath your feet, you would start to feel that your weight begins to disappear as you are falling. Assuming that air resistance did not retard or reduce the impact of your plunge, you would surrender completely to the gravity’s pull and become weightless. This phenomenon is called “zero g-force,” wherein you will not feel you weight in instances where there are no contact forces like the Earth’s gravity that pulls you and determines your heaviness.
It is important to note that weight is calculated by measuring the force of an object or a human that is at rest in a strong gravitational field, which is the Earth’s pull. A human will only be able to measure his or her true weight if he or she comes into constant with floors and other surfaces that are affected by Earth’s gravity.
To get the feel of this weightless condition during training, astronauts would ride in planes that are flown in large ballistic arcs. These practice sessions are usually brief, but they do create, but for only a few seconds, the buoyancy the astronauts will feel when gliding upwards to space. NASA has created special airplanes that are capable of reducing gravity in their interior. The Reduced Gravity Research Program began in 1973 in hopes that they can aid future astronauts to become accustomed to zero gravity and weightlessness during space missions. The official nickname for the first airplane used for the program was “Weightless Wonder.” Today, the program is still going strong, and NASA currently used the “Weightless Wonder VI,” which is a McDonnell Douglas C-9 that flies around the Ellington Field in the Lyndon B. Johnson Space Center. The said aircraft was once a military plane utilized by the US Air Force, the US Navy, and the US Marine Corps. The first of the C-9 models, the C-9A, was retired in September 2005, while the second and third models flew for the final time for military use in July 2014 and September 2011, respectively. The plane used by NASA is the C-9B.
There are several ways for people to avoid weightlessness in certain conditions. The first is by standing on a surface or ground, and this can be achieved by astronauts using belts that will allow them to keep their feet on the floor during space flight. The second method is by using the rocket’s engines to thrust the vehicle itself upwards, as this creates a small gravitational field that forces the bodies of pilots to be pushed downwards.