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Project Mercury
Which was a Pre-Apollo project, manned mission, with a crew of only one astronaut
The Viking Mission cost about 1 billion dollars in 1976.
Which of the following statements is true?
a. Viking missions miscalculated the Mars landing and crashed
b. Viking mission deployed small rovers on surface of Mars
c. Viking mission cost aout 1 billion dollars
d. Viking missions were nuclear powered
e. VIking missions were launched on the Space Shuttle to save money
Cassini-Huygens
was a space probe launched in 1997 to study Saturn and its moons, providing invaluable data and stunning images of the planet and its rings.
The orbiter's mission consists of delivering a probe (called Huygens,
provided by ESA) to Titan, and then remaining in orbit around Saturn for detailed
studies of the planet and its rings and satellites.
Successfully entered orbit
around Saturn at 9:12 p.m.
PDT on June 30, 2004
Pathfinder
Was a NASA mission that successfully landed the first rover on Mars in 1997, enabling extensive exploration and analysis of the Martian surface.
Total Mission Cost: ~$265 million ($542 million in 2024 dollars)
Galileo
was a space probe launched in 1989 to study Jupiter and its moons, providing significant insights into the planet's atmosphere, magnetic field, and its largest moon, Europa. It was launched on the Space Shuttle to save money
VEEGA (Venus-Earth-Earth Gravity Assist)
6 year journey
Where is the most water in the solar sytem? That distinction goes to Europa, moon of Jupiter, seen in this illustration with all its water gathered into a single drop compared to Earth and its water drop. Europa is believed to have over twice as much water by volume as Earth.
Voyager 1 released a probe to surface of Titan, Saturn’s largest moon
Which is false?
a. Voyager 1 & 2 carried a message from President Carter.
b. Voyager 1 & 2 is an example of a space mission with redundancy
c. Voyager 2 did a flyby of Jupiter, Saturn, Uranus, and Neptune
d. Voyager 1 & 2 cost $865 million in 1977
e. Voyager 1 released a probe to surface of Titan, Saturn’s largest moon
Where in the solar system were “blueberries” found?
They were found on Mars, specifically in the Meridiani Planum region, where they were identified by the Opportunity rover.
Facts about human Mars mission
a. Current NASA budget insufficient for human Mars mission.
b. Radiation is a serious health hazard in human Mars missions.
c. Microgravity is a serious health hazard in human Mars mission.
d. Long duration space travel is a potential hazard to crew mental health.
Precursors to Apollo
Ranger Project: Photos of lunar surface and crash landings. (1964-1965)
Surveyor Project: Soft landings on Moon and surface properties. (1966-1968)
Soviet Luna and Zond Series
24 Luna Missions (1959-1976)
Earliest lunar missions, culminating in several robotic rover and sample return missions.
5 Zond Missions (1965-1970)
Precursor to human missions. Round-trips to Moon and back with animals and other biological matter.
Project Gemini
10 manned flights 1965-1966
Subject man and equipment to space-flight up to 2 weeks in duration.
Rendezvous and dock with orbiting vehicles and to maneuver the docked combination.
Perfect methods of entering the atmosphere and landing at a pre-selected point on land
Sputnik
Soviet Union launches first satellite in 1957.
Apollo Program
designed to land humans on the Moon and bring them safely back to Earth.
Scientific accomplishments:
390 kilograms of lunar samples returned to Earth
Experiments on soil mechanics, meteoroids, seismic, heat flow, lunar ranging, magnetic fields, and solar wind experiments.
The Moon is not a primordial object -- it is a differentiated terrestrial planet made of igneous rock.
2. The Moon has an ancient crust that preserves its early history – impact crater record has been calibrated using absolute ages of rock samples.
3. The youngest Moon rocks are virtually as old as the oldest Earth rocks. The earliest processes and events that probably affected both planetary bodies can now only be found on the Moon.
4. The Moon and Earth may be genetically related and formed from different proportions of a common reservoir of astromaterials -- the Moon is highly depleted in iron and in volatile elements that are needed to form atmospheric gases and water.
5. The Moon is lifeless; it contains no living organisms, fossils, or native organic compounds.
6. All Moon rocks originated through high-temperature processes with little or no involvement with water. They are roughly divisible into three types: basalts, anorthosites, and breccias.
7. Early in its history, the Moon was melted to great depths to form a “magma ocean”. The lunar highlands contain the remnants of early, low density rocks that floated to the surface of the magma ocean.
8. The lunar magma ocean was followed by a series of huge asteroid impacts that created basins which were later filled by lava flows.
9. The surface of the Moon is covered by a rubble pile of rock fragments and dust, called the lunar regolith, produced by innumerable meteorite impacts through geologic time.
10. The regolith contains a unique radiation history of the Sun to a degree of completeness that we are unlikely to find elsewhere.
Top 10 Discoveries from Lunar Samples
Saturn V Cost per Launch
$4-5 Billion
Apollo 4
Launched in 1967, first test flight completely successful
Early Venus Flybys and Probes
Mariner 2, Venera 4, Mariner 5, Venera 5/6
Mariner 4
1965 Mars Flyby
First picture clearly showing craters on Mars
Venara 7
First soft landing on Venus
was launched from a Tyazheliy Sputnik in an earth parking orbit towards Venus to study the Venusian atmosphere and other phenomena of the planet.
entered the atmosphere of Venus on December 15, 1970, and a landing capsule was jettisoned. After aerodynamic braking, a parachute system was deployed. The capsule antenna was extended, and signals were returned for 35 min. Another 23 min of very weak signals were received after the spacecraft landed on Venus.
The capsule was the first man-made object to return data after landing on another planet.
Mariner 9
1971 Mars Flyby
Mariner 7
1969 Flyby
Pictures Olympus Mons
Soviet Mars 2,3
First Orbiter and Soft Landing on Mars
1971
Pioneer 10,11
1972-72, FIRST TO JUPITER, SATURN, AND BEYOND (carried gold plate designed by Carl Sagan depicting humanity)
Viking Mission
Two spacecraft:
1 and 2, each consisting of an orbiter and a lander.
Primary mission objectives
High resolution images of the Martian surface
Characterize the structure and composition of the atmosphere and surface
Search for evidence of life
Mission Cost: ~$1 Billion ($5.7 Billion in 2024 dollars)
1 landed in Chryse Planitia and 2 landed in Utopia Planitia
Voyager Project
1 was launched September 5, 1977, and flew past Jupiter on March 5, 1979 and by Saturn on November 13, 1980.
2 was launched August 20, 1977 and flew by Jupiter on August 7, 1979, by Saturn on August 26, 1981, by Uranus on January 24, 1986, and by Neptune on August 8, 1989.
Cost: $865 million ($4.7 Billion in FY2024 dollars)
Together captured Jupiters Great Red Spot, Active volcanism on Io, Saturns rings, and Neptune’s Great Dark Spot
As of July 2007, 1 was at a distance of 15.4 Billion Kilometers (103 AU) from the sun and 2 at a distance of 12.4 Billion kilometers (83 AU). Both spacecraft are still sending scientific information about their surroundings through the Deep Space Network (DSN).
Golden Record
The contents of the record were selected for NASA by a committee chaired by Carl Sagan who assembled 115 images and a variety of natural sounds, such as those made by surf, wind, and thunder, and animal sounds, including the songs of birds and whales. To this they added musical selections from different cultures and eras, and spoken greetings from Earthlings in fifty-five languages, and printed messages from President Jimmy Carter and UN Secretary-General Kurt Waldheim.
After NASA had received criticism over nudity on the Pioneer plaque the agency chose not to allow Sagan and his colleagues to include a photograph of a nude man and a nude, pregnant woman on the record.
President Carter's official statement placed on the space craft:
“We cast this message into the cosmos… Of the 200 billion stars in the Milky Way galaxy, some — perhaps many — may have inhabited planets and space faring civilizations. If one such civilization intercepts Voyager and can understand these recorded contents, here is our message: We are trying to survive our time so we may live into yours. We hope some day, having solved the problems we face, to join a community of Galactic Civilizations. This record represents our hope and our determination and our goodwill in a vast and awesome universe.”
Comet Flybys
International Cometary Explorer
1978
Giacobini-Zinner, Halley
Sakigake 'Pioneer'
1985
Halley
Suisei `Comet'
1985
Halley
Giotto (ESA) 1985 image of Comet Halley Nucleus ~600 km
Magellan
The primary objectives of the mission were to map the surface of Venus with a synthetic aperture radar (SAR) and to determine the topographic relief of the planet.
At the completion of radar mapping 98% of the surface was imaged at resolutions better than 100 m, and many areas were imaged multiple times.
Volcanic "pancake" domes in Tinatin Planitia, Venus
At 280 km diameter, Mead Crater is the largest impact crater on Venus.
Computer generated 3-dimensional perspective view of the "crater farm"
3-dimensional image of Sapas Mons a 1.5 km high volcano
Mars Meteorite ALH84001
ALH84001 Discovery
Organic molecules of Martian origin
Mineral features characteristic of biological activity
Possible microscopic fossils of primitive, bacteria-like organisms
NASA Annual Budget
$24.9 billion for FY 2024
0.37% of total federal budget!
Mars Odyssey Orbiter0.08% of US GDP
Mars Odyssey Orbiter
The mission will map the amount and distribution of chemical elements
and minerals that make up the Martian surface. The spacecraft will
especially look for hydrogen, most likely in the form of water ice, in the
shallow subsurface of Mars. It will also record the radiation environment
in low Mars orbit to determine the radiation-related risk to any future
human explorers who may one day go to Mars.
Genesis
Samples delivered to Earth on Sept. 8, 2004
Crash Landing
picking up the pieces
pieces of the collector array
concentrator target partially intact
Stardust Discovery Mission
the first U.S. space mission
dedicated solely to the exploration of a
comet, and the first robotic mission
designed to return extraterrestrial material
from outside the orbit of the Moon
In 2004, it flew in front
of the nucleus, and through the halo of gases and dust at
the head of comet Wild 2 (within 236 km). During this
passage the spacecraft captured thousands of dust and
volatile particles in its aerogel collector. A volatile is
material difficult to capture or hold permanently. The
comet samples are expected to be made up of ancient
pre-solar interstellar grains and nebular condensates that
were incorporated into comets at the birth of the solar
system
Mars Exploration Rovers
Spirit & Opportunity
Rocks and soils are analyzed with a set of five
instruments on each rover, and a special tool called
the "RAT," or rock abrasion tool, is used to expose
fresh rock surfaces for study. Each rover has a mass
of nearly 180 kilograms (about 400 pounds) and
has a range of up to 100 meters (about 110 yards)
per sol, or Martian day. Requirement for surface
operations duration was for a total of 90 sols.
Mission: MER-A "Spirit"
Launch Date: June 10, 2003
Launch Time: 1:58:47 p.m. EDT
Launch Vehicle: Delta II
Launch Pad: 17-A
Mission: MER-B "Opportunity"
Launch Date: July 7, 2003
Launch Time: 11:18:15 p.m. EDT
Launch Vehicle: Delta II
Launch Pad: 17-B
SPIRIT: Last contact March 22, 2010. Duration 2269
days from landing to last contact (2208 sols) to last
contact: 6 years, 9 months, 12 days. Climbed Columbia Hills
OPPORTUNITY: Last contact on June 10, 2018.
Duration 5,352 sols (5498 Earth days from landing to
mission end; 15 Earth years or 8 Martian years) at Merdiani Planum
Messenger
(Mercury Orbiter)
The spacecraft crashed onto the surface of Mercury on April 30, 2015, at 3:26 p.m. EDT (19:26 GMT), at a velocity of 14,080 km/h (8,750 mph), probably creating a crater in the planet's surface approximately 16 m (52 ft) wide
Wide Angle Camera (WAC), part of the Mercury Dual Imaging System (MDIS), is equipped with 11 narrow-band color filters. As the spacecraft receded from Mercury after making its closest approach on January 14, 2008, the WAC recorded a 3x3 mosaic covering part of the planet not previously seen by spacecraft.
MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission.
[] will enter Mercury orbit in March 2011 and carry out comprehensive measurements for one Earth year.
$286 million total mission cost
Trying to answer the following:
What planetary formation processes led to the high metal/silicate ratio in Mercury?
What is the geological history of Mercury?
What is the nature and origin of Mercury's magnetic field?
What is the structure and state of Mercury's core?
What are the radar-reflective materials at Mercury's poles?
What are the important volatile species and their sources and sinks on and near Mercury?
New Horizons (Pluto Flyby)
a mission designed to fly by Pluto and its moon Charon and transmit images and data back to Earth. It will then continue on into the Kuiper Belt where it will fly by a number of Kuiper Belt Objects and return further data. The primary objectives are to characterize the global geology and morphology of Pluto and Charon, map the surface composition of Pluto and Charon, and characterize the neutral atmosphere of Pluto and its escape rate.
Curiosity
ROVER INSTRUMENTS
MastCam (US) - Color stereo imaging, atmospheric opacity
ChemCam (US/France) – Chemical composition; remote micro-imaging
MAHLI (US) - Microscopic imaging
APXS (Canada) - Chemical composition
SAM (US/France) - Chemical and isotopic composition, including organics
CheMin (US) - Mineralogy
REMS (Spain) - Meteorology/UV
RAD (US/Germany) - High-energy radiation
DAN (Russia) - Subsurface hydrogen
ENTRY, DESCENT and LANDING SYSTEM
MARDI (US) – Descent imaging
Backshell and Heatshield (US)
Thrusters (US)
ROVER INFRASTRUCTURE
High Gain Antenna (Spain)
Integration and Test (Siemens) – CAE/CAD s/w solutions
Wheel/Drive Actuators (US)
Science Objectives
Assessing biological potential of the martian site
Characterizing geology and geochemistry
Investigating the role of water, atmospheric evolution and climate
Characterizing the spectrum of surface radiation
Checked Gale Crater
Perseverance Rover
NASA has invested approximately $2.4 billion to build and launch the Mars 2020 mission. The estimate to land and operate the rover during its prime mission is approximately $300 million.
Jezero Crater
Jezero is a crater on Mars in the Syrtis Major quadrangle, about 45.0 km (28.0 mi) in diameter. Thought to have once been flooded with water, the crater contains a fan-delta deposit rich in clays. The lake in the crater was present when valley networks were forming on Mars. Besides having a delta, the crater shows point bars and inverted channels. From a study of the delta and channels, it was concluded that the lake inside the crater probably formed during a period in which there was continual surface runoff
Helicopter Ingenuity
a small rotorcraft that was part of NASA's Mars 2020 mission along with the Perseverance rover. It was designed to demonstrate powered flight in the thin atmosphere of Mars, making it the first true aircraft to fly on another planet. Ingenuity serves as a technology demonstrator, proving that aerial exploration of Mars is possible, which could enhance future exploration missions. It has successfully completed multiple flights on Mars, testing various flight maneuvers and capabilities, providing valuable data for future aerial missions.
Psyche Mission
is a NASA Discovery Program space mission launched on October 13, 2023, to explore the origin of planetary cores by orbiting and studying the metallic asteroid 16 Psyche beginning in 2029. NASA's Jet Propulsion Laboratory (JPL) manages the project.
Europa Clipper Mission
Europa Clipper is a space probe developed by NASA to study Europa, a Galilean moon of Jupiter. It was launched on October 14, 2024. The spacecraft will use gravity assists from Mars on March 1, 2025, and Earth on December 3, 2026, before arriving at Europa in April 2030.
Artemis Program
is a Moon exploration program led by NASA. It is intended to reestablish a human presence on the Moon for the first time since the Apollo 17 mission in 1972. The program's stated long-term goal is to establish a permanent base on the Moon to facilitate human missions to Mars.
Fewer ambiguous results that can plague in-situ / remote measurements.
Provides ground truth needed to calibrate in-situ / remote sensing data.
Provides radiometric calibration of planet’s cratering history and geologic time scale.
No need to prejudge what we will find -- dilemma of deciding which instruments to fly is avoided.
Ability to design experiments in real time as sample characteristics are revealed.
Why Sample Return?
Mars Receiving Facility (MRF)
The should be a quarantine facility that combines biosafety level 4 (BSL-4) requirements with sample protection requirements.
In other words, the should be designed to protect humans and Earth's environment from potential biohazards in the Mars samples, and it should protect the Mars samples from organic and inorganic contamination from the Earth's environment.
Currently, there is no existing facility that meets requirements.
Theories of Origin of Martian moons
(A)the pair are asteroids captured after the formation of Mars
(B) the moons are fragments scattered during a giant collision (Giant Impact) with Mars that then coalesced.
Based on the results of proximity observations and the analysis of collected samples, the most likely theory for the moons' formation can be clarified.”
Facts about water on Earth
If you gathered up all the water on Earth, both saline and fresh, in a single spherical drop (that’s the big drop over the western U.S. in the illustration above) it would only measure 860 miles in diameter. The second biggest drop in the illustration (hovering over Kentucky) represents all the fresh water on the planet and is just under 170 miles in diameter. The smallest tiniest droplet, seen over Atlanta, Georgia, representing all the fresh water that is in fact accessible to humans, is just 35 miles across
Velocity of Nuclear Pulse Starship
~67,000,000 miles/hour (0.1c) (compared to Voyager 1 38,000 mph)
Flight time of at least 44 years to reach Alpha Centauri.
Origin of Solar System
Historically there have been two competing classes of hypotheses for origin of the solar system.
1. Dualistic or Encounter Hypothesis
Le Clerc (Comte de Buffon) in 1745
T.C. Chamberlain in early 20th century
2. Nebular Hypothesis
Descartes 1644
Immanuel Kant 1755
Laplace 1796
Orion Nebula
giant stellar nursery ~1600 light years away
At the heart of the Orion Nebula lies a complex of molecular clouds where abundant star formation is occurring today.
The clouds are illuminated by a flood of ultraviolet light emitted by four bright stars, collectively called the Trapezium
More than 150 protoplanetary disks have been found in this mosaic of HST images.
At the center of each proplyd (protoplanetary disk) is a T Tauri star.
The disks surrounding them are two to eight times the diameter of our solar system.
He
Our Sun’s fusion only creates , need red giant for heavier elements.
Interplanetary Dust Grain
In this scanning electron microscope image, all the minerals, organic compounds, and amorphous materials look the same. However, isotopic analysis reveals that some components of this dust actually solidified in interstellar space long before our Sun and its planets formed
Chondrules
formed from melted dust grains that were flash-heated in the inner solar nebula.
Terrestrial vs Giant Planets
Mercury, Venus, Earth, Mars (solid mantle)
Jupiter, Saturn, Uranus, Neptune (liquid and gaseous hydrogen and helium)
Fate of Milky Way
Six billion years from now it will merge with the Andromeda galaxy.
At 3.75 billion years from now, Andromeda and the Milky Way prepare for their initial collision.
Sun Fact Sheet
The Sun is a normal G2 star, one of more than 100 billion stars in our galaxy.
Diameter: 1,390,000 km (Earth 12,742 km or nearly 100 times smaller)
Mass: 1.1989 x 1030 kg (333,000 times Earth’s mass)
Temperature: 5800 K (surface) 15,600,000 K (core)
The Sun contains more than 99.8% of the total mass of the Solar System (Jupiter contains most of the rest).
Chemical composition:
Hydrogen 92.1%
Helium 7.8%
Rest of the other 90 naturally occurring elements: 0.1%
Why do the seasons occur
The seasons occur because the tilt of the Earth's axis keeps a constant orientation as the Earth revolves around the Sun. A. Summer in northern hemisphere. B. Winter in southern hemisphere
Energy on the Sun
The seasons occur because the tilt of the Earth's axis keeps a constant orientation as the Earth revolves around the Sun. A. Summer in northern hemisphere. B. Winter in southern hemisphere
The seasons occur because the tilt of the Earth's axis keeps a constant orientation as the Earth revolves around the Sun. A. Summer in northern hemisphere. B. Winter in southern hemisphere
Differential Rotation
Sun does not rotate as a rigid sphere. The equator of the Sun rotates faster than the poles of the Sun. This is called the differential rotation. Sunspots and many other solar activities are due to this differential rotation.
Sun’s Magnetic Field
Sun does not rotate as a rigid sphere. The equator of the Sun rotates faster than the poles of the Sun. This is called the differential rotation. Sunspots and many other solar activities are due to this differential rotation.
When some of the Sun's magnetic field lines are filled with hot gas, we see a magnetic loop.
The most rapid changes to the Sun's [] occur locally, in restricted regions of the magnetic field.
However, the entire structure of the Sun's global [] changes on an 11 year cycle.
Every 11 years, the Sun moves through a period of fewer, smaller sunspots, prominences, and flares - called a "solar minimum" - and a period of more, larger sunspots, prominences and flares - called a "solar maximum.“
After 11 years, when the next cycle starts, the [] poles are reversed.
The last solar minimum was in 2006
Sunspots
Sunspots appear as dark spots on the surface of the Sun. Temperatures in the dark centers of sunspots drop to about 3700 K (compared to 5700 K for the surrounding photosphere). They typically last for several days, although very large ones may live for several weeks.
Spectrum analysis shows that sunspots have strong magnetic field, about 1000 times stronger than the Sun's average. Sunspots usually appear in pairs. The two sunspots of a pair have different polarities, one would be a magnetic north and the other is a magnetic south, and can be joined by magnetic field lines. The strong magnetic field locks the gas of the photosphere in places and inhibits the hotter gas below to rise at the sunspots. As a result, the sunspots are cooler. Sunspots appear to coincide with changes in the climate of the Earth. Studies show that during the last ice age, there were very few sunspots
Granules
Convection from inside the sun causes the photosphere to be subdivided into 1000-2000km cells.
Energy rises to the surface as gas wells up in the cores of the granules, and cool gas sinks around their edges.
Solar Prominences
Prominences are dense clouds of material suspended above the surface of the Sun by loops of magnetic field. Prominences can remain in a quiet or quiescent state for days or weeks. However, as the magnetic loops that support them slowly change, prominences can erupt and rise off of the Sun over the course of a few minutes or hours
Solar Flares
are tremendous explosions on the surface of the Sun. In a matter of just a few minutes they heat material to many millions of degrees and release as much energy as a billion megatons of TNT. They occur near sunspots, usually along the dividing line (neutral line) between areas of oppositely directed magnetic fields.
Coronal Mass Ejections
are huge bubbles of gas threaded with magnetic field lines that are ejected from the Sun over the course of several hours.
disrupt the flow of the solar wind and produce disturbances that strike the Earth with sometimes catastrophic results.
Heliospheric Current Sheet
Largest structure in Solar System, resulting from influence of the Sun’s rotating magnetic field on the solar wind.
Blackbody
Theoretical object which is a perfect radiator
The Sun's spectrum is nearly identical to that of a blackbody radiator. The minor differences occur because gases in the chromosphere and corona selectively absorb some wavelengths of the electromagnetic radiation emitted by the Sun.
The energy flux from [] radiators at different temperatures. Note how the radiation peak moves to shorter wavelengths as the temperature increases. The area under any one curve is the total flux of energy emitted by a radiator at a given temperature. Note that the higher the temperature, the greater the flux.
Hertzsprung-Russell diagram of star luminosity versus surface temperatures
The vertical axis is a comparative one based on the Sun having a luminosity of 1. The horizontal axis is reversed from the normal order, with values of surface temperature increasing to the left. Note that the Sun is a middle-range, main-sequence star.
Hydrogen
By mass, about 70% of the Sun is []. The rest is mostly 4He.
[] is the fuel of the nuclear reaction in the core of the Sun, and helium is the product. Most of the helium is not produced by the Sun. It was already there when the Sun was formed.
Life Cycle of Sun
Birth:
Gravitational Collapse of Interstellar Cloud
"Hayashi Contraction" of Protostar
Life:
Stability on Main-Sequence
Long life - energy from nuclear reactions in the core
(E = mc2)
Death:
Lack of fuel, instability, variability expansion (red giant, then white dwarf)
Mercury Historical
•Mercury is one of the five planets known to the ancients. They called these planets "wandering stars".
•Mercury may be seen as an evening "star" near where the sun has set, or as a morning "star" near where the sun will rise.
•The ancient Greeks called the evening star Hermes and the morning star Apollo, believing them to be different objects.
•The planet is named for Mercury, the Roman messenger of the gods.
Mercury Orbital Facts
Mercury takes only 88 Earth days to complete one orbit, but it rotates slowly about its own axis, only once every 59 Earth days.
This means that it rotates precisely three times for every two orbits, known as a 3:2 orbital resonance.
It orbits the Sun in a highly elliptical orbit at about one third of the Sun-Earth distance. Only the orbit of Pluto, the outermost planet, is more elliptical.
At perihelion (closest approach to the Sun), it is only 46 million kilometers from the Sun, but at aphelion (furthest approach) it is 70 million kilometers away.
The axis of rotation is almost perpendicular to the orbital plane, so Mercury does not have opposite seasons in each hemisphere, as Earth has.
Instead, the temperature at the equator varies as the planet's distance from the Sun changes during its elliptical orbit.
The maximum temperature is 700K (427oC), but the minimum only 90K (-183oC). Mercury has very little atmosphere so the surface cools down rapidly on the night side.
Mstiner 10
was the seventh successful launch in the Mariner spacecraft series, and the first to use the gravitational pull of one planet (Venus) to reach another (Mercury).
Instruments on board the spacecraft were designed to measure the atmospheric, surface, and physical characteristics of Mercury and Venus.
Experiments included television photography, magnetic field, plasma, infrared radiometry, ultraviolet spectroscopy, and radio science detectors. An experimental X-band, high-frequency transmitter was flown for the first time on the spacecraft.
10,000 pictures with 57% planet coverage reveal an intensely cratered, Moon-like surface and a faint atmosphere of mostly helium, resulting from solar wind bombardment.
Mercury’s Atmosphere
Like the Earth’s Moon, [] has a very volatile atmosphere. What little atmosphere exists is made up of atoms or ions blasted off its surface by the solar wind and has less than a million-billionths the pressure of Earth's atmosphere at sea level. It is composed chiefly of oxygen, sodium, and helium.
[] extreme surface temperature enhances the escape of these volatile atoms into space.
With no atmosphere or hydrosphere, there has been no erosion from wind or water.
[] may have water ice at its north and south poles. The ice exists inside deep craters. The floors of these craters remain in perpetual shadow, so the Sun cannot melt the ice.
Meteorites do not burn up due to friction as they do in other planetary atmospheres.
Mercury’s Surface
Highly cratered with smooth terrains.
Relatively ancient, volcanic surface.
Similar to Earth’s Moon, but fewer craters and more “plains”.
Geologically longer active than Moon?
Plains mostly lava or impact ejecta?
Caloris Basin
Largest structure on Mercury ~1300 km
Asteroid-size impactor early in solar system history
Basin contains smooth plains but is highly ridged and fractured
"Weird terrain“, hilly, lineated region.
The shock wave produced by the [] impact was reflected and focused to this antipodal point, thus jumbling the crust and breaking it into a series of complex blocks.
The area covered is about 100 kilometers (62 miles) on a side.
Discovery Rupes
Sinuous feature may be a thrust fault.
This feature and many similar ones on Mercury suggest compressional forces and 1-2 km radial shrinkage planet-wide.
Cooling, contraction od Mercury at end of volcanically active early history?
Mercury’s Interior
density is similar to Earth’s, but planet is only ~1/3 the size of Earth.
Large iron core, 75% of radius (~1850 km), Silicate mantle only ~550 km thick.
Origin of Mercury’s Large Core
Unknown, but hypotheses include:
1.Radial compositional (iron) zonation of the inner solar system.
●
Young [] was a larger planet, but giant impact removed much of mantle
