Lecture 2 Flashcards
What is the equatorial surface gravity of Earth, Moon and Mars?
- Earth: 9,78033 m/s^2
- Moon: 1,622 m/s^2
- Mars: 3,711 m/s^2
What is the rotation period of Earth, Moon and Mars?
- Earth: 23,93 siderial hours
- Moon: 655,72 siderial hours
- Mars: 24,62 siderial hours
What is the surface temperature of Earth, Moon and Mars?
- Earth: 185/331 K
- Moon: 26/396 K
- Mars: 145/294 K
What is the ambient pressure at sea level of Earth, Moon and Mars?
- Earth: 1013 mbar
- Moon: 10^-11 to 10^-10 mbar
- Mars: 6 mbar
What are the 7 main environmental factors on an astronomical object?
- Vacuum
- Gravity
- Illumination
- Temperature
- Radiation
- Impacts
- Dust
What are the effects and consequences of vacuum?
- No oxygen –> life support system
- Pressure difference –> pressure suit, reinforced structures
- No convection –> highly variable thermal stress (sunlit planes/shadowed craters)
- Material outgassing –> degradation, damage, contamination
- No atmospheric drag –> meteoroid bombardment
When did vacuum start to be intensively studied and what are 3 experiments on vacuum?
- 17th century
- 1654: Magdeburg hemispheres, air/vacuum pump
- 1646: First human-made vacuum
- 1660: No sound in vacuum
What happens to a human in space?
- Air sucked out of lungs (holding breath causes tissue rupture)
- Blood boils off
- Other liquids boil off (Eyes, Tongue)
- Local freezing
- Ultimately full freezing, slower
What are effects and consequences of gravity?
- Reduced contact to ground –> reduced traction and control, risk of bouncing off
- Increased dust aggregation –> compromised vision, increased contamination
- Varied fluid behaviour –> bubble growth/detachment and reduced convection (for reactors)
How long is a day on all planets in the solar system relative to Earth?
- Mercury: 175.9
- Venus: 116.8
- Earth: 1
- Mars: 1.03
- Jupiter: 0.41
- Saturn: 0.44
- Uranus: 0.72
- Neptune: 0.67
What is the relation between radiation intensity and distance from radiating object?
I = 1/r^2
(Intensity I, Distance r)
What are effects and consequences of illumination?
- Limited power supply –> energy storage, other power sources
- Reduced radiation intensity –> other power sources
- Extreme temperature gradients –> thermal stress, damage, wide design envelope
- Psychological effects –> psychological stress, mood
How are the illumination conditions on the Moon?
- 14 days illumination vs. 14 days darkness
What are PEL’s and PSR’s?
- PEL: Peaks of Eternal Light
- PSR: Permanently Shadowed Regions
Where can PEL’s and PSR’s be found and what are their benefits?
- No evidence for “eternal light”, but peaks with illumination 80% of the time
- Moon, Mercury, Ceres
- Benefit: continuous power close to potential resource deposits
What are effects and consequences of temperature?
- Temporal/spatial gradients –> thermal stress (dynamic/static), thermal expansion
- Extreme values –> enhanced outgassing, increased power demand
What are sources of radiation?
- High energy galactic cosmic rays (GCR) –> Mainly protons (85%) and alpha particles (14%)
- Solar particle events (SPE) –> X-rays, gamma rays, protons and electrons
What are effects and consequences of radiation?
- DNA and cell damage –> Cataracts, gene mutations, increased chance of cancer, sterility
- Jamming/damage of electronics –> Computer errors (glitches, bit flips, latchups, burnouts)
What are some effects of Earth’s magnectic field?
- Shields radiation
- Traps highly energetic particles in the Van-Allen Belts
Where are the 2 Van-Allen Belts located and where is a relatively safe zone?
- Inner belt: 0.2 to 2 Earth radii, mainly protons
- Outer belt: 3 to 10 Earth radii, protons and electrons with highest intensity around 4 to 5 Earth radii
- Safe zone inbetween
How much radiation dose is experienced on a trip to Mars compared to the recommended value for an average career?
> 60%
What are some radiation effects on CMOS (Complementary Metal-Oxide Semiconductor)?
Ionisation process causes energy to be trapped in the materials (dose), leading to:
- Oxide doping (fixed charge, leading to lower barrier, threshold shifts)
- Leakage current (device stays „on“ even with no gate voltage)
What are some single event effects on CMOS (Complementary Metal-Oxide Semiconductor)?
- Single Event Transients (heavy ion creates voltage pulse along its path)
- Single Event Upsets (device changes its logical state, e.g. bitflip)
- Single Event Latch Up (low impedance, electric short, loss of device functionality)
In what sense was the Apollo-Program “lucky”?
- No major solar-particle events occurred during Apollo
