Nasa speaks of the either the space shuttle or the ISS

In summary, the conversation discusses the effects of Earth's gravity and how NASA communicates about it. It is noted that the people on the ISS are falling towards Earth at the same speed as the craft around them, and that NASA uses terms like "weightlessness" and "microgravity" to describe this state. However, it is also mentioned that this does not mean gravity has no effect on the shuttle and that there may be a misunderstanding about the effects of gravity. The conversation also touches on the concept of "actual weight" versus "apparent weight" and how a bathroom scale measures the latter. Overall, the conversation highlights the complexity of gravity and how it is communicated by NASA.
  • #1
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how come when NASA speaks of the either the space shuttle or the ISS, they speak as if they have left the effects of Earth's gravity? This is not true. The people in the ISS are falling toward Earth at the same speed as the craft around them. When they start their decent back to Earth they feel weightless until they touch atmosphere. At that point the atmosphere slows the craft and the people inside feel the G's from that. Are some of the smartest people that nieve to think that we can acually leave the effects of Earth's gravity, becouse i don't think that is possable.
 
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  • #2
neh4pres said:
Are some of the smartest people that nieve to think that we can acually leave the effects of Earth's gravity, becouse i don't think that is possable.
What effects are you talking about? Remember that locally it is impossible to establish if you are in a gravitational field. Note that a spacecraft is relatively small.
 
  • #3
the planets pull on our sun. the Earth pulls on the moon and keeps it in an orbit. the collective of our galaxy pulls on other galaxy's. I don't think it is possable to leave the effects of the Earth's gravity. So how come NASA fumbles these words.
 
  • #4
neh4pres said:
the planets pull on our sun. the Earth pulls on the moon and keeps it in an orbit. the collective of our galaxy pulls on other galaxy's. I don't think it is possable to leave the effects of the Earth's gravity. So how come NASA fumbles these words.

I think all NASA are saying is that the effect of gravity on small scale experiments conducted inside the space shuttle is almost zero. This allows them to carry our certain "zero gravity" experiments in the shuttle that would be difficult or impossible within the Earth's atmosphere. Of course it does not mean that gravity does not have an effect on the shuttle.
 
  • #5
neh4pres said:
the planets pull on our sun. the Earth pulls on the moon and keeps it in an orbit. the collective of our galaxy pulls on other galaxy's. I don't think it is possable to leave the effects of the Earth's gravity. So how come NASA fumbles these words.
I think there is something you misunderstand about the effects of gravity. One of the effects of gravity we can measure are the so-called tidal effects For a small localized area you can effectively ignore those effects and a spaceship is very small in this respect.

Of course the curvature of spacetime does influence how objects move with respect to each other and sometimes they bump into each other but that does not influence any laws of physics as the bodies all move inertially. Inside the spaceship there are, except for the extremely small tidal effects, and things like precessions, no effects whatsoever due to gravity.
 
  • #6
neh4pres, you are thinking too little. Of course NASA knows that Earth's gravity doesn't end at the Earth's surface.

MeJennifer, you are thinking too much. NASA doesn't expect the average citizen of the US to have the foggiest idea about tidal gravity effects.NASA use of words like weightlessness and microgravity is (a) often aimed at the average US citizen, and (b) correct. "Weight" comes in two flavors. "Actual weight" is tautologically defined as mass times the acceleration due to gravity. The "actual weight" of an astronaut floating around in the near-weightlessness of the ISS is close to the astronaut's actual weight on the surface of the Earth. Nothing, including a bathroom scale, can measure "actual weight" directly because nothing can sense gravity directly.

A bathroom scale measures "apparent weight". The "apparent weight" of some object is the net sum of all real forces except for gravity acting on the object. (Note that from a relativistic perspective, apparent weight is the net sum of all real forces acting on an object, period, as gravitation isn't a real force in relativity; it's a pseudoforce instead.) An astronaut in the ISS is not quite in free fall because the astronaut is not at the ISS center of gravity and the ISS is subject to atmospheric drag. The astronaut will fall very slowly toward some surface of the ISS. The acceleration is very, very tiny. Earthbound viewers see the astronauts floating around as if they were weightless. As nothing, including the astronauts themselves, can sense actual weight, the astronauts feels themselves floating around apparently weightless.
 
  • #7


D H said:
A bathroom scale measures "apparent weight". The "apparent weight" of some object is the net sum of all real forces except for gravity acting on the object. (Note that from a relativistic perspective, apparent weight is the net sum of all real forces acting on an object, period, as gravitation isn't a real force in relativity; it's a pseudoforce instead.) An astronaut in the ISS is not quite in free fall because the astronaut is not at the ISS center of gravity and the ISS is subject to atmospheric drag. The astronaut will fall very slowly toward some surface of the ISS. The acceleration is very, very tiny. Earthbound viewers see the astronauts floating around as if they were weightless. As nothing, including the astronauts themselves, can sense actual weight, the astronauts feels themselves floating around apparently weightless.

thanks... this is very insightful... you think deeply,as do I.
 

What is the purpose of the space shuttle and the International Space Station (ISS)?

The space shuttle and the ISS are both used for scientific research, technological development, and space exploration. They serve as a platform for experiments, observations, and testing of new technologies in a microgravity environment. Additionally, they are used for transporting crew and supplies to and from the ISS.

How long has the space shuttle program been in operation?

The space shuttle program began in 1981 and ended in 2011. During this time, there were 135 missions and 355 individuals from 16 different countries flew on the space shuttle.

How is the ISS different from the space shuttle?

The ISS is a long-term orbital laboratory, while the space shuttle was a reusable spacecraft used for shorter missions. The ISS is also much larger, able to accommodate multiple crew members for extended periods of time, while the space shuttle could only hold a maximum of seven astronauts.

What type of research is conducted on the space shuttle and ISS?

The space shuttle and ISS are used for a wide range of research, including studies on human physiology, biology, physics, astronomy, and Earth observation. This research helps us better understand our planet, the universe, and the effects of space on the human body.

How is NASA involved with the space shuttle and ISS?

NASA is responsible for the design, development, and operation of both the space shuttle and the ISS. NASA also coordinates and oversees the scientific research conducted on these platforms. Additionally, NASA works with international partners to maintain and supply the ISS.

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