However, scientists predict the sun's activity in 2013 may not be as productive at the cleanup effort as in previous years, still the thermosphere will continue to expand as the sun moves toward its 2013 solar maximum, which could mean that more particles will fall back toward the planet.
According to the NASA, the energy from these intense solar eruptions, known as coronal mass ejections, will cause the atmosphere to expand and create more friction for the space junks in orbit, and the resulting drag could send these debris plummeting back to Earth.
During periods of escalated solar activity such as increases in sunspots, solar flares, and coronal mass ejections, the sun dumps more energy into Earth's atmosphere. "When the sun is more active, it ejects more energy in the direction of Earth," Nick Johnson, chief scientist for NASA's Orbital Debris Program in Houston Johnson said. "
In NASA's latest edition of its Orbital Debris Quarterly News, Johnson noted that about half of the pieces of monitored space trash from the Chinese weather satellite that re-entered the atmosphere crashed back to Earth in 2011. In addition, more space trash was added during a collision between an American and a Russian communications satellite in 2009.
NASA tracks more than 500,000 pieces of debris, or "space junk," which travel at speeds up to 17,500 mph, as they orbit the Earth. The rising population of space debris increases the potential danger to all space vehicles, but especially to the International Space Station, space shuttles and other spacecraft with humans aboard.
The threat of collisions with space debris is a serious issue and NASA has a set of guidelines on how to deal with potential collision threats. These guidelines specify evasive action or other precautions when the expected proximity of a piece of debris increases the probability of a collision to ensure the safety of the crew are needed.
In NASA's guidelines, an imaginary box about a mile deep by 30 miles across by 30 miles long, known as the "pizza box" is drawn around the space vehicle. When predictions indicate that a debris will pass close enough for concern and the quality of the tracking data is deemed sufficiently accurate, Mission Control centers in Houston and Moscow work together to develop a prudent course of action.
When these encounters are in advance, the station is ordered to move slightly, known as a "debris avoidance maneuver," to keep the debris outside of the box.
When the tracking data does not warrant such a maneuver or the close pass is not identified in time to make the maneuver, the best course of action could be to move the crew into the Soyuz spacecraft that are used to transport humans to and from the station to allow enough time to isolate those spaceships from the station.
By closing hatches in the event of a damaging collision, the crew would be able to leave the station if the collision caused a loss of pressure in the life-supporting module or damaged critical component.
Additional precautions such as closing hatches between some of the station's modules may be ordered by Mission Controls if the likelihood of a collision is great enough, according to the NASA guidelines.
If the probability of collision reaches limits set in the space shuttle and space station flight rules, debris avoidance maneuvers are planned. Based upon specific flight rules and detailed risk analysis, NASA decides if a collision avoidance maneuver is necessary.
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