Space Systems 101 - Unit 1 Review

Flashcards about the space environment, solar activity, and related hazards.

What is the Karman line according to international standards?

100 km above the Earth

According to U.S. government standards, what is the domain of USSPACECOM?

100 km above mean sea level

What is the exobase, according to the scientific community?

500 to 1000 km; the atmosphere ends no air for airplanes to fly.

How does the sun continuously produce energy?

Nuclear fusion of hydrogen protons into helium

What is the sun's composition?

74.9% hydrogen, 23.8% helium, 1.3% misc. gases

What are the interior layers of the sun?

Core, radiative zone, convective zone

What is the surface layer of the sun?

Photosphere

What are the atmosphere layers of the sun?

Chromosphere, corona

What is the core of the sun?

Where fusion occurs, rotates like a solid

What is the radiative zone of the sun?

Radiates energy through photon emission and capture, moves like a fluid

What is the convective zone of the sun?

Uses thermal convections, moving plasma disrupts magnetic field, moves like a fluid

What is the photosphere?

Opaque to light, 99% of solar radiation, sunspots visible

What layers comprise the solar atmosphere?

Chromosphere, transition region, corona, and heliosphere

What is the tachocline?

Magnetic field lines generated here, strong radial differential rotation

What characterizes the solar minimum?

Few to zero sunspots, dimmer EUV and x-rays, minimal flaring/CME

What characterizes the solar maximum?

Many sunspots, brighter EUV and x-rays, frequent flaring/CME

How long does a full solar cycle last?

11 years

What is solar wind?

A stream of charged particles released from the corona.

What is a solar flare?

A sudden burst of high-energy particles and radiation.

What are Solar Energetic Particles (SEPs)?

High-energy particles emanating from the sun outside the standard solar wind.

What is a Coronal Mass Ejection (CME)?

An event in which a massive cloud of energetic, magnetized solar plasma is launched into space.

What is the magnetosphere?

Also known as the geomagnetic field.

How does solar wind affect the magnetosphere?

Compresses the sun side and drags out the night side into elongated field lines.

What are the Van Allen Belts?

Belts of trapped charged particles from the sun that result in a high radiation environment.

What characterizes the outer Van Allen belt?

Populated with trapped solar wind electrons, not very stable.

What characterizes the inner Van Allen belt?

Populated with protons from geomagnetic storms, more energetic and stable.

What is the ionosphere?

Made of plasma, ionized gas consisting of positive ions and free electrons.

What is plasma frequency?

Frequencies at or below this can be reflected towards earth like a mirror.

What is scintillation?

Variation in amplitude, phase, and polarization of transmitted signals, resulting in signal fading and data dropouts.

What are the three categories of space weather storms?

Radio blackouts (solar flares), solar radiation storms (particle events), geomagnetic storms (CMEs).

What factors determine the effect of a solar flare or CME on Earth?

Size and location of the flare/CME, and direction of the magnetic field.

What does the Earth's magnetic field primarily protect against?

Solar wind

What is outgassing, and what is its mitigation?

Occurs when plastics/composites release trapped gasses (mitigation: baking in a vacuum).

What is cold welding, and what is its mitigation?

No atmosphere to act as a lubricant between mechanical parts (mitigation: minimize moving parts, select lubricants).

What are the methods of heat transfer in space, and what are the mitigations?

Conduction, convection, and radiation (mitigation: radiation only transfer method, manage temps using conduction and convection structures).

What is sputtering, and what is its mitigation?

Occurs when particles contact spacecraft at high speeds (mitigation: hardening/shielding).

What is a single event upset, and what is its mitigation?

Occurs when a charged particle makes a deep penetration of the spacecraft (mitigation: warning of conditions, evasive actions).

What is the total ionizing dose effect?

Long-term damage to the crystal structure of semiconductors caused by electrons in the solar wind and van allen belts.

What is atmospheric drag?

Occurs when space objects collide with atmospheric molecules, causing damage.