Space environment
Encyclopedia
Space environment is a branch of astronautics
, aerospace engineering
and space physics
that seeks to understand and address conditions existing in space that affect the operation of spacecraft. A related subject - space weather
- deals with dynamic processes in the solar-terrestrial system that can give rise to effects on spacecraft, but that can also affect the atmosphere, ionosphere
and geomagnetic field, giving rise to several other kinds of effects on human technologies.
Effects on spacecraft can arise from radiation
, space debris
and meteoroid
impact, upper atmospheric drag and spacecraft electrostatic charging.
Radiation in space usually comes from three main sources: (i) the Van Allen radiation belts; (ii) solar proton event
s and solar energetic particles; and (iii) galactic cosmic rays. For long duration missions, the high doses of radiation can damage electronic components and solar cells. A major concern is also radiation-induced "single-event effects" such as single event upset
. Manned missions usually avoid the radiation belts and the international space station
is at an altitude well below the most severe regions of the radiation belts. During solar energetic events (solar flares and coronal mass ejections) particles can be accelerated to very high energies and can reach the Earth in times as short as 30 minutes (but usually take some hours). These particles are mainly protons and heavier ions that can cause radiation damage, disruption to logic circuits and even hazards to astronauts. Manned missions to return to the Moon or to travel to Mars will have to deal with the major problems presented by solar particle events to radiation safety, in addition to the important contribution to doses from the low-level background cosmic rays. In near-Earth orbits, the Earth's geomagnetic field screens spacecraft from a large part of these hazards - a process called geomagnetic shielding.
Space debris and meteoroids can impact spacecraft at high speeds, causing mechanical or electrical damage. The average speed of space debris is 10 km/s while the average speed of meteoroids is much greater. For example, the meteoroids associated with the Perseid meteor shower
travel at an average speed of 58 km/s. Mechanical damage from debris impacts have been studied through space missions including LDEF, which had over 20,000 documented impacts through its 5.7 year mission. Electrical anomalies associated with impact events include ESA's Olympus spacecraft, which lost attitude control during the 1993 Perseid meteor shower. A similar event occurred with the Landsat 5
spacecraft during the 2009 Perseid meteor shower.
Spacecraft electrostatic charging is caused by the hot plasma
environment around the Earth. The plasma encountered in the region of the geostationary orbit becomes heated during geomagnetic "sub-storms" caused by disturbances in the solar wind. "Hot" electrons (with energies in the kilo-electron volt range) collect on surfaces of spacecraft and can establish electrostatic potentials of the order of kilovolts. As a result, discharges can occur and are known to be the source of many spacecraft anomalies.
Solutions devised by scientists and engineers include, but are not limited to, spacecraft shielding, special "hardening" of electronic systems, various collision detection systems. Evaluation of effects during spacecraft design includes application of various "models' of the environment, including radiation belt models, spacecraft-plasma interaction models and atmospheric models to predict drag effects encountered in lower orbits and during reentery.
The field often overlaps with the disciplines of astrophysics
, atmospheric science, space physics
, and geophysics
, albeit usually with an emphasis on application.
The United States government maintains a Space Weather Prediction Center at Boulder, Colorado
. The Space Weather Prediction Center (SWPC) is part of the National Oceanic and Atmospheric Administration
(NOAA). SWPC is one of the National Weather Service
's (NWS) National Centers for Environmental Prediction
(NCEP).
Space weather
effects on Earth can include ionospheric
storms, temporary decreases in ozone
densities, disruption to radio communication, to GPS signals and submarine positioning. Some scientists also theorize links between sunspot
activity and ice age
s. http://ff.org/centers/csspp/library/co2weekly/20060920/20060920_13.html
Astronautics
Astronautics, and related astronautical engineering, is the theory and practice of navigation beyond the Earth's atmosphere. In other words, it is the science and technology of space flight....
, aerospace engineering
Aerospace engineering
Aerospace engineering is the primary branch of engineering concerned with the design, construction and science of aircraft and spacecraft. It is divided into two major and overlapping branches: aeronautical engineering and astronautical engineering...
and space physics
Space physics
Space physics, also known as space plasma physics, is the study of plasmas as they occur naturally in the universe. As such, it encompasses a far-ranging number of topics, including the sun, solar wind, planetary magnetospheres and ionospheres, auroras, cosmic rays, and synchrotron radiation...
that seeks to understand and address conditions existing in space that affect the operation of spacecraft. A related subject - space weather
Space weather
Space weather is the concept of changing environmental conditions in near-Earth space or thespace from the Sun's atmosphere to the Earth's atmosphere. It is distinct from the concept ofweather within the Earth's planetary atmosphere...
- deals with dynamic processes in the solar-terrestrial system that can give rise to effects on spacecraft, but that can also affect the atmosphere, ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
and geomagnetic field, giving rise to several other kinds of effects on human technologies.
Effects on spacecraft can arise from radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
, space debris
Space debris
Space debris, also known as orbital debris, space junk, and space waste, is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to erosion, explosion...
and meteoroid
Meteoroid
A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. The visible path of a meteoroid that enters Earth's atmosphere is called a meteor, or colloquially a shooting star or falling star. If a meteoroid reaches the ground and survives impact, then it is called a meteorite...
impact, upper atmospheric drag and spacecraft electrostatic charging.
Radiation in space usually comes from three main sources: (i) the Van Allen radiation belts; (ii) solar proton event
Solar proton event
A Solar proton event occurs when protons emitted by the Sun become accelerated to very high energies either close to the Sun during a solar flare or in interplanetary space by the shocks associated with coronal mass ejections. These high energy protons cause several effects. They can penetrate the...
s and solar energetic particles; and (iii) galactic cosmic rays. For long duration missions, the high doses of radiation can damage electronic components and solar cells. A major concern is also radiation-induced "single-event effects" such as single event upset
Single event upset
A single event upset is a change of state caused by ions or electro-magnetic radiation striking a sensitive node in a micro-electronic device, such as in a microprocessor, semiconductor memory, or power transistors. The state change is a result of the free charge created by ionization in or close...
. Manned missions usually avoid the radiation belts and the international space station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
is at an altitude well below the most severe regions of the radiation belts. During solar energetic events (solar flares and coronal mass ejections) particles can be accelerated to very high energies and can reach the Earth in times as short as 30 minutes (but usually take some hours). These particles are mainly protons and heavier ions that can cause radiation damage, disruption to logic circuits and even hazards to astronauts. Manned missions to return to the Moon or to travel to Mars will have to deal with the major problems presented by solar particle events to radiation safety, in addition to the important contribution to doses from the low-level background cosmic rays. In near-Earth orbits, the Earth's geomagnetic field screens spacecraft from a large part of these hazards - a process called geomagnetic shielding.
Space debris and meteoroids can impact spacecraft at high speeds, causing mechanical or electrical damage. The average speed of space debris is 10 km/s while the average speed of meteoroids is much greater. For example, the meteoroids associated with the Perseid meteor shower
Perseids
The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides , a term found in Greek mythology...
travel at an average speed of 58 km/s. Mechanical damage from debris impacts have been studied through space missions including LDEF, which had over 20,000 documented impacts through its 5.7 year mission. Electrical anomalies associated with impact events include ESA's Olympus spacecraft, which lost attitude control during the 1993 Perseid meteor shower. A similar event occurred with the Landsat 5
Landsat 5
Landsat 5 is the fifth satellite of the Landsat program. It was launched on March 1, 1984, with the primary goal of providing a global archive of satellite photos. The Landsat Program is managed by USGS, and data from Landsat 5 is collected and distributed from the USGS's Center for Earth Resources...
spacecraft during the 2009 Perseid meteor shower.
Spacecraft electrostatic charging is caused by the hot plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
environment around the Earth. The plasma encountered in the region of the geostationary orbit becomes heated during geomagnetic "sub-storms" caused by disturbances in the solar wind. "Hot" electrons (with energies in the kilo-electron volt range) collect on surfaces of spacecraft and can establish electrostatic potentials of the order of kilovolts. As a result, discharges can occur and are known to be the source of many spacecraft anomalies.
Solutions devised by scientists and engineers include, but are not limited to, spacecraft shielding, special "hardening" of electronic systems, various collision detection systems. Evaluation of effects during spacecraft design includes application of various "models' of the environment, including radiation belt models, spacecraft-plasma interaction models and atmospheric models to predict drag effects encountered in lower orbits and during reentery.
The field often overlaps with the disciplines of astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
, atmospheric science, space physics
Space physics
Space physics, also known as space plasma physics, is the study of plasmas as they occur naturally in the universe. As such, it encompasses a far-ranging number of topics, including the sun, solar wind, planetary magnetospheres and ionospheres, auroras, cosmic rays, and synchrotron radiation...
, and geophysics
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
, albeit usually with an emphasis on application.
The United States government maintains a Space Weather Prediction Center at Boulder, Colorado
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
. The Space Weather Prediction Center (SWPC) is part of the National Oceanic and Atmospheric Administration
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration , pronounced , like "noah", is a scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere...
(NOAA). SWPC is one of the National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...
's (NWS) National Centers for Environmental Prediction
National Centers for Environmental Prediction
The United States National Centers for Environmental Prediction delivers national and global weather, water, climate and space weather guidance, forecasts, warnings and analyses to its Partners and External User Communities...
(NCEP).
Space weather
Space weather
Space weather is the concept of changing environmental conditions in near-Earth space or thespace from the Sun's atmosphere to the Earth's atmosphere. It is distinct from the concept ofweather within the Earth's planetary atmosphere...
effects on Earth can include ionospheric
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
storms, temporary decreases in ozone
Ozone
Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...
densities, disruption to radio communication, to GPS signals and submarine positioning. Some scientists also theorize links between sunspot
Sunspot
Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....
activity and ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
s. http://ff.org/centers/csspp/library/co2weekly/20060920/20060920_13.html
See also
- Space weatherSpace weatherSpace weather is the concept of changing environmental conditions in near-Earth space or thespace from the Sun's atmosphere to the Earth's atmosphere. It is distinct from the concept ofweather within the Earth's planetary atmosphere...
- AstronauticsAstronauticsAstronautics, and related astronautical engineering, is the theory and practice of navigation beyond the Earth's atmosphere. In other words, it is the science and technology of space flight....
- Outer spaceOuter spaceOuter space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....
- Space scienceSpace scienceThe term space science may mean:* The study of issues specifically related to space travel and space exploration, including space medicine.* Science performed in outer space ....
- Karman lineKarman lineThe Kármán line lies at an altitude of above the Earth's sea level, and is commonly used to define the boundary between the Earth's atmosphere and outer space...
- Space Environment Data System - SEDATSEDATSEDAT provides access to near-original satellite data on the space environment in order to perform analyses and queries needed for evaluation of space environment hazards.- History :...
- Space Environment Information System - SPENVIS
- ECSSEuropean Cooperation for Space StandardizationThe European Cooperation for Space Standardization , established in 1993, is an organization which works to improve standardization within the European space sector. The ECSS frequently publishes standards, to which contractors working for ESA must adhere to.-References:*- External links :* * at...
standard E-ST-10-04C on Space environment