Space environment

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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 design and 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.

Contents

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:

  1. The Van Allen radiation belts
  2. Solar proton events and solar energetic particles; and
  3. 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. Crewed 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. Crewed 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 (22,000 mph; 36,000 km/h) [1] 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 (130,000 mph; 210,000 km/h). [2] 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. [3] Electrical anomalies associated with impact events include ESA's Olympus spacecraft, which lost attitude control during the 1993 Perseid meteor shower. [4] A similar event occurred with the Landsat 5 spacecraft [5] during the 2009 Perseid meteor shower. [6]

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 substorms 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 reentry.

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 ages.

Space environmentalism

Space environmentalism is an advocacy that sees space as not devoid of needing regulation and protection, and has gained attention by an increasing number of academics, [7] such as Moriba Jah. [8]

See also

Related Research Articles

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The Leonids are a prolific meteor shower associated with the comet Tempel–Tuttle, which are also known for their spectacular meteor storms that occur about every 33 years. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky. Their proper Greek name should be Leontids, but the word was initially constructed as a Greek/Latin hybrid and it has been used since. They peak in the month of November.

Solar wind Stream of charged particles from the Sun

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei such as C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, 54Fe and 56Fe, and 58Ni, 60Ni, and 62Ni. Superposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field.

Solar flare Eruption of electromagnetic radiation in the atmosphere of the Sun

A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other solar phenomena. The occurrence of solar flares varies with the 11-year solar cycle.

Van Allen radiation belt Zone of energetic charged particles around the planet Earth

A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetosphere. Earth has two such belts, and sometimes others may be temporarily created. The belts are named after James Van Allen, who is credited with their discovery. Earth's two main belts extend from an altitude of about 640 to 58,000 km above the surface, in which region radiation levels vary. Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays. By trapping the solar wind, the magnetic field deflects those energetic particles and protects the atmosphere from destruction.

Meteoroid Sand- to boulder-sized particle of debris in the Solar System

A meteoroid is a small rocky or metallic body in outer space.

Space weather Branch of space physics and aeronomy

Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the time varying conditions within the Solar System, including the solar wind, emphasizing the space surrounding the Earth, including conditions in the magnetosphere, ionosphere, thermosphere, and exosphere. Space weather is distinct from but conceptually related to the terrestrial weather of the atmosphere of Earth. The term space weather was first used in the 1950s and came into common usage in the 1990s. Later, it was generalized to a "Space Climate" research discipline which focuses on general behaviors of longer and larger-scale variabilities and effects.

Geomagnetic storm Disturbance of the Earths magnetosphere

A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field.

Meteor shower Celestial event caused by streams of meteoroids entering Earths atmosphere

A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Very intense or unusual meteor showers are known as meteor outbursts and meteor storms, which produce at least 1,000 meteors an hour, most notably from the Leonids. The Meteor Data Centre lists over 900 suspected meteor showers of which about 100 are well established. Several organizations point to viewing opportunities on the Internet. NASA maintains a daily map of active meteor showers.

Micrometeoroid Meteoroid with a mass of less than one gram

A micrometeoroid is a tiny meteoroid: a small particle of rock in space, usually weighing less than a gram. A micrometeorite is such a particle that survives passage through Earth's atmosphere and reaches Earth's surface.

Atmosphere Layer of gases surrounding an astronomical body held by gravity

An atmosphere is a layer of gas or layers of gases that envelope a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules.

Perseids Prolific meteor shower associated with the comet Swift-Tuttle

The Perseids are a prolific meteor shower associated with the comet Swift–Tuttle. The meteors are called the Perseids because the point from which they appear to hail lies in the constellation Perseus.

Space Weather Prediction Center

The Space Weather Prediction Center (SWPC), named the Space Environment Center (SEC) until 2007, is a laboratory and service center of the US National Weather Service (NWS), part of the National Oceanic and Atmospheric Administration (NOAA), located in Boulder, Colorado. SWPC continually monitors and forecasts Earth's space environment, providing solar-terrestrial information. SWPC is the official source of space weather alerts and warnings for the United States.

Interplanetary dust cloud Small particles between planets

The interplanetary dust cloud, or zodiacal cloud, consists of cosmic dust that pervades the space between planets within planetary systems, such as the Solar System. This system of particles has been studied for many years in order to understand its nature, origin, and relationship to larger bodies.

Space physics, also known as solar-terrestrial physics or space-plasma physics, is the study of plasmas as they occur naturally in the Earth's upper atmosphere (aeronomy) and within the Solar System. As such, it encompasses a far-ranging number of topics, such as heliophysics which includes the solar physics of the Sun, the solar wind, planetary magnetospheres and ionospheres, auroras, cosmic rays, and synchrotron radiation. Space physics is a fundamental part of the study of space weather and has important implications in not only to understanding the universe, but also for practical everyday life, including the operations of communications and weather satellites.

Health threats from cosmic rays are the dangers posed by cosmic rays to astronauts on interplanetary missions or any missions that venture through the Van-Allen Belts or outside the Earth's magnetosphere. They are one of the greatest barriers standing in the way of plans for interplanetary travel by crewed spacecraft, but space radiation health risks also occur for missions in low Earth orbit such as the International Space Station (ISS).

Energetic neutral atom Technology to create global images of otherwise invisible phenomena

Energetic neutral atom (ENA) imaging, often described as "seeing with atoms", is a technology used to create global images of otherwise invisible phenomena in the magnetospheres of planets and throughout the heliosphere.

Sigrid Close is a professor in the Department of Aeronautics and Astronautics at Stanford University. Her primary research interest is the space environment with particular focus on meteoroids, meteors, and orbital debris, and their interaction with spacecraft and spacecraft operations.

Solar particle event Solar phenomenon

In solar physics, a solar particle event (SPE), also known as a solar proton event, prompt proton event, or solar radiation storm, is a solar phenomenon which occurs when particles emitted by the Sun, mostly protons, become accelerated either in the Sun's atmosphere during a solar flare or in interplanetary space by a coronal mass ejection shock. Other nuclei such as helium and HZE ions may also be accelerated during the event. These particles can penetrate the Earth's magnetic field and cause partial ionization of the ionosphere. Energetic protons are a significant radiation hazard to spacecraft and astronauts.

ESA Vigil, formerly known as Lagrange, is a planned solar weather mission by the European Space Agency. It envisions two spacecraft to be positioned at Lagrangian points L1 and L5.

Gerhard Drolshagen is a German physicist at the University of Oldenburg, Germany, specializing in space environment and near-Earth objects (NEO). He has been a staff member at the European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Noordwijk, The Netherlands (1987–2016) and is known for his work in space environment, NEO and for the asteroid named after him: the asteroid 332733 Drolshagen.

References

  1. ↑ Meteoroids and Orbital Debris: Effects on Spacecraft (NASA Reference Publication 1408)
  2. ↑ Here Come the Perseids!
  3. ↑ Orbital Debris Impacts on Spacecraft
  4. ↑ The sad story of Olympus 1 Archived 2011-09-28 at the Wayback Machine
  5. ↑ Landsat 5 Experiences Malfunction
  6. ↑ The 2009 Perseid Meteor Shower
  7. ↑ Lawrence, Andy; Rawls, Meredith L.; Jah, Moriba; Boley, Aaron; Vruno, Di; Garrington, Simon; Kramer, Michael; Lawler, Samantha; Lowenthal, James; McDowell, Jonathan; McCaughrean, Mark (2022-04-22). "The case for space environmentalism". Nature Astronomy. 6 (4): 428–435. doi:10.1038/s41550-022-01655-6. ISSN   2397-3366 . Retrieved 2022-05-25.
  8. ↑ Wood, Danielle (7 April 2021). "Media Lab Perspectives: Space Environmentalism with Moriba Jah – MIT Media Lab". MIT Media Lab. Retrieved 3 February 2022.
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