Radiation astronomy/Materials

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The MISSE are usually loaded on the outside of International Space Station. The inset image shows where. Credit: NASA.

"Space is considered an environment — an extreme environment, filled with entities that can be harmful to spacecraft."[1]

"In space, there are several environmental threats that can harm materials used to create spacecraft. These threats include ultraviolet rays and x-rays from the sun; solar wind particle radiation; thermal cycling (hot and cold cycles); space particles (micrometeoroids and debris); and atomic oxygen."[1]

"Since 2001, NASA and its partners have operated a series of flight experiments called Materials International Space Station Experiment, or MISSE. The objective of MISSE is to test the stability and durability of materials and devices in the space environment."[1]

"PECs [Passive Experiment Containers], which are attached to the exterior of the International Space Station, are about 2-feet by 2-feet and hold a variety of materials samples and devices whose reactions in space are of interest."[1]

"The PECs are positioned in either a ram/wake orientation or in a zenith/nadir orientation. The ram orientation is the direction in which the space station is traveling, and the wake orientation faces the direction traveled. The zenith orientation faces away from Earth into space, while the nadir orientation faces straight down to Earth. Each orientation exposes the samples to different space environmental factors."[1]

Micrometeoroids[edit | edit source]

The damage was caused by micrometeoroid impact. Credit: NASA.

"At the Kennedy Space Center [...], engineers are assessing options for fixing a radiator panel mounted on the inside of the shuttle Atlantis' right-side payload bay door. The panel apparently was damaged when a piece of space debris or a micrometeoroid slammed into the radiator, presumably during the shuttle's flight last month [September 2006], blasting .108-inch-wide hole in the upper surface and destroying the aluminum honeycomb material below before exiting the other side."[2]

"The impact did not threaten the crew and the damage can be repaired. But it illustrates the danger posed by micrometeoroid/orbital debris (MMOD) and the reason why NASA considers such strikes a high risk. The odds of a catastrophic impact-related entry failure range between 1-in-210 to 1-in-350, depending on whether the astronauts inspect the ship in orbit prior to re-entry."[2]

"A preliminary engineering analysis shows the impact in question was one of the most significant instances of MMOD damage in shuttle history, second only to a cargo bay door impact during shuttle mission STS-72 in 1996."[2]

"The shuttle's 60-foot-long payload bay doors each feature four radiator panels that are exposed to space once the doors are opened in orbit. The forward two radiator panels measure about one inch thick, feature Freon coolant tubes positioned about 1.9 inches apart and can pivot to radiate from both sides. The aft panels are fixed and only radiate from one side. They measure a half inch thick and feature coolant tubes separated by about 5 inches. The interior of the panels is made up of an aluminum honeycomb material."[2]

"The impact on Atlantis's right-side, or starboard, radiator was found roughly midway between two coolant lines on panel No. 4. The object blasted a .108-inch-wide hole and presumably broke apart on impact. The resulting spray of debris created a cone-shaped damage cavity immediately below the face plate, destroying the honeycomb interior to the full half-inch depth of the panel. The lower face sheet was pushed out in two places. A .26-inch crack and a .03-inch-wide exit hole were found."[2]

"At orbital velocities, even tiny pieces of debris pose a serious threat. An aluminum sphere just .4 inches across moving at 10 kilometers per second, or 22,370 mph, carries the same impact energy as a bowling ball moving at 300 mph."[2]

Hypotheses[edit | edit source]

  1. The use of satellites should provide ten times the information as sounding rockets or balloons.

A control group for a radiation satellite would contain

  1. a radiation astronomy telescope,
  2. a two-way communication system,
  3. a positional locator,
  4. an orientation propulsion system, and
  5. power supplies and energy sources for all components.

A control group for radiation astronomy satellites may include an ideal or rigorously stable orbit so that the satellite observes the radiation at or to a much higher resolution than an Earth-based ground-level observatory is capable of.

See also[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 1.4 Sheldon (April 29, 2011). Materials: Out of This World. Washington DC USA: NASA News. http://spacestationinfo.blogspot.com/2011_04_01_archive.html. Retrieved 2014-01-08. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 William Harwood (October 6, 2006). Shuttles to resume nighttime launches; Atlantis damaged. Spaceflight Now. http://www.spaceflightnow.com/shuttle/sts116/061006nighttime/. Retrieved 2013-10-29. 

External links[edit | edit source]

{{Radiation astronomy resources}}{{Repellor vehicle}}