orbital motion - Gravity on the International Space Station - Physics Stack

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** Gravity on the International Space Station **

up vote 9 down vote favorite
*4*
We created a table in my physics class which contained the strength of
gravity on different planet and objects in space. At altitude 0(earth), the
gravitational strength is 100%. On the moon at altitude 240,000 miles, it's
.028%. And on the International Space Station at 4,250 miles, the
gravitational strength compared to the surface of the earth is 89%.

Here's my question: Why is the strength of gravity compared to the surface
of the earth 89% even though it appears like the ISS has no gravity since
we see astronauts just "floating" around?

newtonian-gravity orbital-motion reference-frame centrifugal-force
celestial-mechanics

share|improve this question
edited Feb 6 at 0:56
Qmechanic♦
30.6k64093
asked Jun 11 '12 at 20:39
SuperStack
148114

up vote 20 down vote accepted
The effective gravity inside the ISS is very close to zero, because the
station is in free fall. The effective gravity is a combination of gravity
and acceleration.

If you're standing

Source: physics.stackexchange.com/questions/29929/gravity-on-the-international-space-station

International Space Station - Wikipedia, the free encyclopedia

--------------------

** International Space Station **

"ISS" redirects here. For other uses, see ISS (disambiguation).

International Space Station
A rearward view of the International Space Station backdropped by the limb
of the Earth. In view are the station's four large, gold-coloured solar
array wings, two on either side of the station, mounted to a central truss
structure. Further along the truss are six large, white radiators, three
next to each pair of arrays. In between the solar arrays and radiators is a
cluster of pressurised modules arranged in an elongated T shape, also
attached to the truss. A set of blue solar arrays are mounted to the module
at the aft end of the cluster.
The International Space Station on 23 May 2010 as seen from the departing
Space Shuttle /Atlantis/ during STS-132.
Station statistics
COSPAR ID 1998-067A
Call sign /Alpha/
Crew Fully crewed 6
Currently aboard 3
(Expedition 40)
Launch 1998
Launch pad Baikonur 1/5 and 81/23
Kennedy LC-39
Mass approximately 450,000 kg (990,000 lb)
Length 72.8 m (239 ft)
Width 108.5 m (356 ft)
Height c. 20 m (c. 66 ft)
(27 November 2009)^[/dated info/]
Pressurised volume 837 m^3 (29,600 cu ft)
(21 March 2011)
Atmospheric pressure 101.3 kPa (29.91 inHg, 1 atm)
Perigee 420 km (260 mi) AMSL^[1]
Apogee 424 km (263 mi) AMSL^[1]
Orbital inclination 51.65 degrees^[1]
Average speed 7.66 kilometres per second (27,600 km/h; 17,100 mph)^[1]
Orbital period 92.88 minutes^[1]
Orbit epoch 18 May 2014^[1]
Days in orbit 5659
(19 May)
Days occupied 4946
(19 May)
Number of orbits 88677^[1]
Orbital decay 2 km/month
Statistics as of 9 March 2011
(unless noted otherwise)
References: ^[1]^[2]^[3]^[4]^[5]^[6]
Configuration
The components of the ISS in an exploded diagram, with modules on-orbit
highlighted in orange, and those still awaiting launch

Source: en.wikipedia.org/wiki/International_Space_Station