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The Earth - Moon Neighborhood Once we leave the Earths atmosphere we are in space. However, the Earth - Moon Neighborhood is actually very crowded with A variety of man made objects, (satellites) and a lot of natural phenomenon like the Van Allen Radiation Belt, Near Earth Asteroids (NEA’s), also known as Near Earth Objects (NEO’s).
There are hundreds of satellites orbiting the Earth at a variety of orbital altitudes and inclinations. Some times there are satellite crashes, creating a lot of orbital debris.
There are thousands of Near Earth Asteroids, of various sizes, some of which actually pass between the Earth and the Moon. Some enter the Earth’s atmosphere, and some actually impact the Earth (that might be why we care about them – see the Tunguska Event).
In addition there are special locations of interest where large space structures can be in a stable orbit in the Earth - Moon Neighborhood. These locations are called Lagrange Libration Points (a good place for a large space structure or a colony).
S. Akerley 2011
The Earth - Moon Neighborhood
N# Distance Designation1000 Miles
N1 4.0 2008 TC3N2 7.9 2004 FU162N3 8.3 2008 TS26N4 18.9 2008 USN5 20.8 2004 YD5
N80 241.7 2007 YN1N81 247.2 2008 WO2N82 259.1 2002 GQN83 263.7 2007 YS56N84 265.5 1995 FFN85 265.5 2004 XP14N86 266.5 2006 JY26N87 267.4 2008 LDN88 278.4 1996 JA1N89 278.4 2006 BH99N90 281.2 2003 XVN91 281.2 1991 VG
L4
L5
L1 L2Earth
Lagrange Libration Point L5
Geo-Synchronous Earth Orbit (GEO Approx. 22,500 miles Altitude)
Lagrange Libration Point L4
Space Station Orbit (LOE) (Approx. 150 miles Altitude) (Atmosphere ends at 65 miles Altitude) (Hubble Telescope approx. 300 - 600 miles Altitude)
NEAsNear Earth AsteroidsOver the last 18 Years,More than 90 NEAs have been identified or have passed between the Earth and Moon Orbits. An Average of 5 per year.It is estimated that there are about 5000NEAs of various sizes.Some have or will enter the Earths Atmosphere, and some will impact the Earth..
N1 N2 N3 N4
N79 N89
Note: Lagrange Libration Point L4 and L5Are equidistant from Earth and MoonAt the Moons orbital distance
Moon
(238,900 miles)
Van Allen Radiation Belt(30,000 to 40,000 miles)
S. Akerley 2011
400 Meter DiameterS. Akerley 2011
S. Akerley 2011
Close Encounters
Different types of NEANear Earth Asteroid “Fly By” Encounters
Earth’s Gravity Well
art work courtesy of NASAS. Akerley 2011
Gravity Wells
Earth L5 Moon Near Earth Asteroids (NEA)
Review of the