Chapter 24: Space Environment Flashcards
What region of the atmosphere is composed mostly of hydrogen and helium?
Photosphere
Electrically conductive zone in upper atmosphere
Ionosphere
Which layer of a star’s atmosphere is characterized by spicules?
Chromosphere
Ionized gas and magnetic field play an important role here
Magnetosphere
Enormous area of white light emanating from the sun’s surface
Corona
Steady emissions from the sun made up of many different types of atoms and ions
Solar winds
Areas of lower density in the sun’s crown
Corona holes
Cooler area that appears dark on the photosphere
Sun spot
Hair-like phenomena that characterizes the chromosphere
Spicules
Non-cyclic eruptions that can harm space assets
Solar winds
The space between the extent of one solar system and another
Interstellar
What aspects of the Sun affect the space environment in our solar system?
The Sun’s gravity, energy emissions, and magnetic fields
How many estimated other solar systems are in our galaxy?
100 billion
3.26 times the distance of a light year
A parsec
Approximately how many light years would it take to reach the nearest solar system in our galaxy?
4 light years
The diameter of the Sun is more than how many times the diameter of the earth?
100 times
The sun’s magnetic field is how many more times the strength of Earth’s magnetic field?
100 times
The space between the Earth and the Moon
Cislunar space
USAF administratively defines the space as beginning at how many miles above the Earth?
50 miles
Why do some experts define space as beginning at 80 miles above the Earth?
It’s the point where an orbiting object will stay in orbit
What is the name of our galaxy?
The Milky Way
The distance a photon can travel in 365 Earth days; it is 5.878 trillion miles
Light Year
The surface of the Sun rotates at different rates, varying from __ days at the Equator to __ days at the poles, but it is generally accepted that the average is __ days
25, 40, 27
The sunspot cycle varies between __ and __ years, but usually follows close to a/an __ year cycle.
8, 15, 11
The less dangerous electromagnetic radiation from this solar phenomenon can reach the Earth in as little as 9 minutes
Solar flare
The more dangerous high energy particles from solar flares may take anywhere from __ minutes to __ days to reach to Earth.
15, 3
Begins 217 miles above the Earth’s surface and extends 10 or 15 Earth radii to the boundary between the atmosphere and the interplanetary plasma
Magnetosphere
When the magnetosphere is struck by _____, is formed into a bow shock wave distorting it and pushing it out past the ________.
Solar winds, orbit of the moon
Made up mostly of electrons and nuclei of atoms; travel at nearly the speed of light, but have their flow greatly reduced by solar winds
Cosmic rays
Thought to be crescent-shaped and composed of two shells; their most significant threat to astronauts is radiation, which may be as high as 65 times the safe exposure.
Van Allen Radiation Belts
Characterized by a sudden onset of radiation bursts in which the magnetic field undergoes marked changes in an hour or less
Magnetic storms
Caused by electron density variations in the ionosphere and resulting in rapid changes in radio signals; causes stars to twinkle
Scintillation
When tiny bubbles of gas escape from the materials of the spacecraft due to the vacuum of space
Outgassing
Occurs when the tiny amount of air escapes from between two surfaces of the spacecraft and they fuse; may be prevented using dry graphite as a lubricant
Cold welding
Occurs when one part of a spacecraft gets charged and has a different charge than another part of the craft
Differential charging
There is strong agreement that space begins 82 miles above the Earth’s surface
FALSE
The solar atmosphere consists of
The photosphere, the chromosphere, and the corona
The sun’s output is fairly consistent and any variance does not impact space operations
FALSE
Short-wave radio is used for local broadcasting, while the long-wave radio is used for international broadcasting because it bounces off the ionosphere better.
TRUE
What are SIDs in the ionosphere?
Sudden ionospheric disturbances
