© Mark Ollig
Today, there are more than 8,800 tons of metal fragments circling Earth.
Non-working satellites and miscellaneous assorted items manufactured on Earth orbit above our planet serving no useful purpose.
This space-clutter, mostly comprised of aluminum, is, in other words, space junk.
NASA defines space debris as “Derelict spacecraft and upper stages of launch vehicles, carriers for multiple payloads, debris intentionally released during spacecraft separation from its launch vehicle or during mission operations, debris created as a result of spacecraft or upper stage explosions or collisions, solid rocket motor effluents, and tiny flecks of paint released by thermal stress or small particle impacts.”
While researching space debris, I was surprised to learn there is such a large amount of it above us.
About 525,000 pieces of space debris measuring three-fourths of an inch to 4 inches are traveling around our planet at 17,500 mph.
There are also more than 100 million marble-sized space debris objects orbiting Earth.
The US Space Surveillance Network currently monitors orbiting space debris larger than 4 inches, and its ground radar is capable of tracking space objects as small as one-tenth of an inch.
I once viewed a photograph of the windshield from a space shuttle damaged by a small piece of space debris.
The surface of the triple-paned glass had a visible shattered impact area with a miniature crater about one-quarter-inch wide.
Within 1,250 miles of our planet’s surface is where most space junk is orbiting; significant debris clusters are inside 500 miles.
What about the International Space Station (ISS) and its vulnerability to being struck by space debris?
The average orbital height of the ISS is 250 miles, which puts it within reach of space debris.
“The ISS is the most heavily shielded spacecraft ever flown,” NASA has reassuringly stated.
NASA said the shielding protecting the ISS crew compartments and high-pressure holding tanks could withstand a space object impact of one-half an inch.
On average, once a year, the ISS needs to use its thruster engines to maneuver away from larger pieces of space debris.
The duration of time in which space debris will orbit around our planet before its eventual re-entry into Earth’s atmosphere varies.
Objects in orbit within 375 miles above Earth will take several years before re-entering the planet’s atmosphere.
An object orbiting around 500 miles above the planet will take decades before its orbit decays and falls back to the surface.
Usually, telecommunication and weather-related satellites are in a 2,200-mile-high orbit from Earth.
Owners of these satellites will maneuver them into a higher orbit toward the end of their useable lifecycle. Sending them further away from Earth diminishes their chance of colliding with and disrupting an operational satellite, not to mention creating more space debris.
Sometimes, not all parts from a spacecraft or satellite burn up when re-entering Earth’s atmosphere.
In July 1979, NASA’s Skylab space station, weighing nearly 170,000 pounds, re-entered Earth’s atmosphere, scattering debris on Balladonia in western Australia and Nullabor Plain in south Australia. At the time, 1.25 million people were living in the area. There were no reported injuries.
Today, a museum in Esperance, western Australia, displays some of the recovered Skylab debris.
May 8, China’s “Long March 5B” rocket, weighing some 50,000 pounds, descended from Earth orbit and crashed into the Indian Ocean, west of the Maldives islands, where 531,000 people live. Luckily again, there were no reported injuries.
“Decades of space activity have littered Earth’s orbit with debris; and as the world’s space-faring nations continue to increase activities in space, the chance for a collision increases correspondingly,” reads a statement from the National Space Policy of the United States of America.
To get a better perspective on the amount of space debris surrounding our planet, watch this NASA video animation at https://go.nasa.gov/3ezy3wm.
With more satellites orbiting the Earth, the more crowded it will become, which increases the chance of satellite-to-satellite collision resulting in additional space debris.
Some scientists have said they fear the thousands of new satellites launched within the coming years will block ground-based telescope observations of many stars and planets.
Another concern about a dramatic increase in satellite and space debris is how it will adversely affect the radio transmission and reception capacity of NASA’s Deep Space Network to communicate with interplanetary spacecraft missions.
NASA’s Orbital Debris Program Office website is http://www.orbitaldebris.jsc.nasa.gov.
You can find the current location of the ISS and when it will be over your area at https://spotthestation.nasa.gov.
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| Source: NASA |
