The Space Environment Flashcards
What space environmental effects originate from the Sun?
- Solar gravitational field
- Solar magnetic field
- Solar wind
- Solar electrons and protons
What space environmental effects originate from nonsolar sources?
- Galactic cosmic rays
- Interplanetary material (Comets, asteroids, gas, dust)
What are the 8 planets of our solar system (from closest to Sun to furthest from Sun)?
- Mercury
- Venus
- Earth
- Mars
- Jupiter
- Saturn
- Uranus
- Neptune
What is the relation between orbital speed of solar objects and the mean distance from the Sun?
The further away from the Sun, the slower the orbital speed
What is the inclination of the orbital planes of all 8 planets in the solar system?
- Mercury: 6.3°
- Venus: 2.2°
- Earth: 1.6°
- Mars: 1.7°
- Jupiter: 0.3°
- Saturn: 0.9°
- Uranus: 1.0°
- Neptune: 0.7°
What is the mean temperature on each planet of the solar system in Kelvin?
- Mercury: 440K
- Venus: 735K
- Earth: 288K
- Mars: 215K
- Jupiter: 163K
- Saturn: 133K
- Uranus: 78K
- Neptune: 72K
What are some (2) spheres protecting the earth from solar particles and effects?
- Radiation belts and Magnetosphere
- Atmosphere and Ionosphere/Plasmasphere
What are some (4) types of Exoplanets and what percentage of the total amount of found Exoplanets do the make up?
- Gas Giants (Size of Jupiter, Saturn or bigger), 30%
- Terrestrial (Small, rocky, around size of Earth), 4%
- Neptune-like (Size of Uranus or Neptune, can also be warm), 35%
- Super-Earths (Size between Earth and Neptune), 31%
What are some (4) active Exoplanet Missions?
- Hubble
- Gaia
- TESS
- James-Webb-Space-Telescope
What are some (6) exoplanet detection methods?
- Transit photometry
- Transit-timing variation
- Radial velocity
- Microlensing
- Astrometry
- Direct imaging
How does Transit photometry for discovering Exoplanets work?
Measures dimming of star’s light when a planet passes in front of it
How does Transit-timing variation for discovering Exoplanets work?
Observes variations in the timing of a planet’s transit across its star, which can indicate the gravitational influence of additional planets in the system
How does Radial velocity for discovering Exoplanets work?
Measures the wobbling motion of a star due to the gravitational pull of an orbiting planet, detected through shifts in the star’s spectral lines (Blue Shift, Star moves toward us, Red Shift, Star moves away from us)
How does Microlensing for discovering Exoplanets work?
Detects planets by observing the bending and magnification of light from a distant star when a planet passes between the star and the observer, acting as a gravitational lens
How does Astrometry for discovering Exoplanets work?
Measures the precise movements of a star in the sky to detect the gravitational influence of an orbiting planet, causing a small but detectable wobble in the star’s position
How does Direct Imaging for discovering Exoplanets work?
Captures images of exoplanets by blocking out the star’s light to see the planets directly, typically using advanced optics and techniques to reduce glare from the star
What are some (5) discovered Exoplanes?
- Kepler-16b
- Kepler-22b
- Kepler-452b
- KELT-9b
- WASP-12b
What 2 forms of “Weather” is Space Weather made of?
Solar Weather + Cosmic Weather, but often it is just Solar Weather
What is the definition of Solar weather?
It is the dynamical transfer of energy from the Sun to the Earth in the form of solar photons, charged particles, and fields that vary on multiple time and spatial scales
What cycle does the Sun usually go through?
It goes through an 11-year Solar Cycle in which its activity varies, going from low (Solar minimum) to high (Solar maximum) to low activity.
What were some (2) notable Solar Particle Events in the last 200 years?
- Carrington Event, 1859
- Halloween Storms, 2003
How does the solar rotation vary?
The poles rotate slower (35 days), the equator rotates faster (25 days)
What is the structure of the Sun from core to outer layer?
- Inner core
- Radiative zone
- Convection zone
- Photosphere (Sunspots and Plages occur here)
- Chromosphere
- Corona (Coronal mass ejections occur here)
What is the sphere called where space is influenced by solar wind (1) and what does it do in context of extrasolar particles (2)?
- Heliosphere
- Protects the solar system, much like the magnetic field of the Earth, from interstellar wind and cosmic rays
What forms when the solar wind interacts with Earth’s magnetosphere?
Bow shock
What are coronal holes?
Disruptions in the Sun’s magnetic field, allowing solar wind to escape more easily.
What is solar wind (1), what protects Earth from most of it (2) and what can it disrupt (3)?
- Continuous stream of electrically charged particles
- Earth’s magnetic field
- Satellites, power grids and communications
How are sunspots and solar flares formed?
Due to unequal rotation, the magnetic field lines of the Sun, usually running from south to north, start stretching and become twisted, eventually bursting through the surface, forming loops. Past a critical point, it blasts away and a solar storm occurs
What are geomagnetic storms (1) and what are they associated with(2)?
- Large disturbances in the near-Earth environment, caused by solar wind and interplanetary field structures
- Major disturbances in the geomagnetic field, strong increase of energetic ions near earth, occasional intense fluxes of relativistic electrons in the outer van Allen radiation belt
What are the van Allen radiation belts?
Two layers of charged particles surrounding earth, trapped by Earth’s magnetic field, consisting of inner (proton) belt and outer (electron) belt
What are magnetospheric substorms?
A temporary disturbance in Earth’s magnetosphere when stored magnetic energy is rapidly released, increasing the number of energetic particles in the magnetosphere and intensifying auroras.
What is the correlation between sunspots and magnetic storms?
The more sunspots, the more magnetic storms
What are some (4) important radiation units?
- Gray (Gy), amount of radiation that deposits 1 J/kg in a material
- Rad, amount of radiation that deposits 0.01 J/kg in a material
- Dose, amount of radiation energy deposited in a material as a function of time
- Total dose, amount of radiation deposited over the life of a material
What are some (5) forms of radiation and what energies (in eV) can they achieve?
- Human-produced radiation, 104 to 108 eV
- Solar energetic photons, 104 to 108 eV
- Radiation belts, 109 eV for protons, 107 eV for electrons
- Solar energetic particles, 109 to 111 eV
- Galactic cosmic rays, 1021 eV
What are some (6) technologies affected by space weather?
- Aviation
- Navigation
- Communication
- Satellite operations
- Energy production
- Power grid
How are satellites affected by space weather?
- Increased atmospheric drag due to higher density caused by solar particles (atmosphere expands and is heated)
- Attitude perturbations affecting pointing precision and gas supply
- End-of-life timing and location
What does space weather / radiation cause in solar panel arrays?
Decreasing power
What can cause heating (1) and cooling (2) in a spacecraft?
- Sun, internal heating, earth, moon, other planets, atmospheric friction, micrometeorites
- Radiation to a cooler environment
How do thermal conditions in space differ from earth?
- No natural air convection source to conduct heat
- Fast temperature variation in vacuum
How is the radiation intensity of the Sun defined?
H0 = (Rsun^2)/(D^2) * Hsun
- H0 is the radiation intensity
- Rsun is the radius of the Sun
- D is the distance from the Sun
- Hsun is the power density at the Sun’s surface
What are some typical thermal requirements for batteries (1), antennas (2) and solar panels (3)?
- 0 to 15°C for operation, -10 to 25°C for surviving
- -100 to 100°C for operation, -120 to 120°C for surviving
- -150 to 110°C for operation, -200 to 130°C for surviving
What are the major parameters driving the Thermal Control System?
- Environment of operation
- Total amount of heat dissipated on board of the spacecraft
- Distribution of thermal dissipation inside the spacecraft
- Temperature requirements for equipment
- Configuration of the spacecraft and its reliability/verification requirements
How big is interplanetary dust usually (1) and what is an example of what it can cause (2)?
- Around 1 micrometer
- Zodiacal light
What are the following objects?
1. Comet
2. Asteroid
3. Meteoroid
4. Meteor
5. Meteor shower
6. Fireball
7. Bolide
8. Meteorite
- Solid body of ice, rock, dust and frozen gases, has a nucleus (>10km) and tail (>1000000km)
- Small, rocky, iron or icy debris (1m to >100km)
- A small asteroid (<1m)
- Light emitted from a meteoroid or asteroid as it enters atmosphere
- Event when Earth passes through region with high concentration of debris (e.g. particles left by comet)
- Meteor brighter than Venus
- Light emitted by a large meteoroid or asteroid as it explodes
- Fragment of a meteoroid or asteroid which reaches the ground
What are some (2) major asteroid belts and where are they located?
- Main Asteroid Belt (Between Mars and Jupiter)
- Trojan Asteroids (Jupiter’s orbit)
How much space debris is there of the size (1) >10cm, (2) >1cm and (3) >1mm
- 34000
- 670000
- 170 million
What causes space debris?
- Collision events
- Fragmentation events
- Military tests
- Separation events
- Defunct satellites
What is the Kessler syndrome?
It is a scenario in which the density of objects in LEO due to space pollution is high enough that collisions between objects cause a cascade in which each collision generates debris which increases the likelihood of more collisions
How often does the ISS have to move out of the way of dangerous debris (1) and what size of debris can it withstand (2)?
- About once a year
- Up to 1cm
How many satellites are there expected to enter orbit in the future?
Around 70000
