Transcript MESSENGER Mission to Mercury

MESSENGER
Mission to Mercury
Heather Weir
NASA-GSFC/SSAI
August 9, 2006
Lunar
Reconnaissance
Orbiter
MESSENGER
New
Horizons
MESSENGER Mission to
Mercury
http://messenger.jhuapl.edu/
Mercury: Some basic properties
• Closest planet to the
Sun (0.39 AU)
• Orbital period: 88 days
• Length of one day
(sunrise to sunrise): 176
Earth days
– One day on Mercury is
two of its years long!
• 3:2 spin-orbit (rotates
three times about its spin
axis for every two orbital
revolutions)
3:2 Spin-Orbit Resonance
• A solar day (the
length between two
meridian transits of
the Sun) lasts about
176 Earth days.
• A sidereal day (the
period of rotation)
lasts about 58.7
Earth days.
Mercury – The Planet
• Seen with the ‘naked’ or unaided
eye, 2 hours before sunrise or after
sunset.
• Surface very Moon-like
• Has an atmosphere (but extremely
tenuous)
• Very low gravity (3.7m/s2)
• Daytime temperature: 450 degrees
Celsius, or 840 degrees Fahrenheit
(lead melts at 327.5 °C).
• Night-time temperature: -212
Celsius, or -350 Fahrenheit (oxygen
changes from gas to liquid below 183.0 °C).
Planets Over Stonehenge
Credit & Copyright: Philip Perkins
http://antwrp.gsfc.nasa.gov/apod/ap020509.html
Solar System
(sizes to scale, distances not to scale)
Mercury:
One of the Terrestrial Planets
Terrestrial planets: rocky Earth-like planets
Mercury
Venus
Earth
(sizes not to scale)
Mars
Mercury:
The Extreme of the Terrestrial Planets
In this group, Mercury
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Is the smallest
Is the densest
Besides Earth, only one with global magnetosphere
Has one of the oldest surfaces
Has largest daily changes in surface temperature
(-180ºC to 450ºC; or -300ºF to 850ºF)
• Is the least explored
Visitors to Mercury
Mariner 10
• 3 fly-bys in 1974 & 1975
• Mapped ~45% of planet’s
surface scaled down to 1
kilometer
• Revealed – impact craters;
smooth and rough terrain,
global magnetic field; thin
atmosphere, & iron-rich
core creating high
uncompressed density.
MESSENGER – MErcury Surface, Space
ENvironment, GEochemistry, and Ranging
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NASA Discovery Mission
1 Earth fly-by, 2 Venus fly-bys, 3 Mercury fly-bys
Orbit Mercury – map almost the complete planet
Launch 08/03/04 Orbit: 03/18/11
Data collection concludes: ~03/18/2012
NASA, Carnegie Institute of Washington, and John
Hopkins University (Applied Physics Laboratory)
Mission
State-of-the-art spacecraft equipped with cutting-edge
technology and top-quality instruments
• Only the second spacecraft
ever to visit Mercury
– Mariner 10 flew by three
times in 1974-1975
• First ever to study the
planet from orbit:
– Close-up observations for
one Earth year
Science Payload
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Mercury Dual Imaging System (MDIS): This
instrument consists of wide-angle and narrow-angle
imagers that will map landforms, track variations in
surface spectra and gather topographic information. A
pivot platform will help point it in whatever direction
the scientists choose. The two instruments will enable
MESSENGER to “see” much like our two eyes do.
Gamma-Ray and Neutron Spectrometer (GRNS):
This instrument will detect gamma rays and neutrons
that are emitted by radioactive elements on Mercury's
surface or by surface elements that have been
stimulated by cosmic rays. It will be used to map the
relative abundances of different elements and will
help to determine if there is ice at Mercury’s poles,
which are never exposed to direct sunlight.
X-Ray Spectrometer (XRS): Gamma rays and highenergy X-rays from the Sun, striking Mercury's
surface, can cause the surface elements to emit lowenergy X-rays. XRS will detect these emitted X-rays
to measure the abundances of various elements in the
materials of Mercury's crust.
Magnetometer (MAG): This instrument is at the end
of a 3.6 meter (nearly 12-foot) boom, and will map
Mercury's magnetic field and will search for regions
of magnetized rocks in the crust.
Science Payload
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Mercury Laser Altimeter (MLA): This instrument
contains a laser that will send light to the planet’s
surface and a sensor that will gather the light after it
has been reflected from the surface. Together they
will measure the amount of time for light to make a
round-trip to the surface and back. Recording
variations in this distance will produce highly
accurate descriptions of Mercury’s topography.
Mercury Atmospheric and Surface Composition
Spectrometer (MASCS): This spectrometer is
sensitive to light from the infrared to the ultraviolet
and will measure the abundances of atmospheric
gases, as well as detect minerals on the surface.
Energetic Particle and Plasma Spectrometer
(EPPS): EPPS measures the composition,
distribution, and energy of charged particles
(electrons and various ions) in Mercury's
magnetosphere.
Radio Science (RS): RS will use the Doppler effect
to measure very slight changes in the spacecraft's
velocity as it orbits Mercury. This will allow
scientists to study Mercury's mass distribution,
including variations in the thickness of its crust.
Science Questions
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Why is Mercury so dense?
What is the geologic history of Mercury?
What is the structure of Mercury’s core?
What are the nature and origin of Mercury's
magnetic field?
• What are the unusual materials at Mercury’s
poles?
• What is the nature of Mercury’s atmosphere?
Why Study Mercury?
• Understanding the "end member" of the terrestrial
planets holds unique clues to the questions of
– the formation of the Solar System
– evolution of the planets
– magnetic field generation and magnetospheric physics
• Exploring Mercury will also help us understand
– how our own Earth was formed
– how Earth has evolved
– how Earth interacts with the Sun
Timeline
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2006
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2008
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2009
2011
2012
Launch (Aug. 3)
Earth Flyby I (Aug. 1)
Venus Flyby I (Oct. 24)
Venus Flyby II (Jun. 6)
Mercury Flyby I (Jan. 15)
Mercury Flyby II (Oct. 6)
Mercury Flyby III (Sept. 30)
Enter Orbit (Mar. 18)
End orbital operations
Challenges for a mission to Mercury:
• How to get there?
• How to stay comfortable?
• How to make the
spacecraft reliable?
Staying Cool
• Spacecraft will be exposed to:
– 5-11 times the amount of sunlight than if near Earth
– More than 20 times the amount of solar radiation than if near
Earth
• Precautions taken
– Sunshade pointed towards the Sun (at all times)
– Highly elliptical orbit (egg-shaped)
• 200 kilometers (124 miles) above the surface at the lowest point
• more than 15,193 kilometers (9,420 miles) at the highest.
– Solar panels
• 70% optical solar reflectors (mirrors)
• 30% solar cells
Ice on Mercury?
• High radar reflectivity
near the north and south
poles
• Permanently shadowed
craters near the poles
• Possible sources
– meteorite bombardment
– large comet impact
– planetary outgassing
http://nssdc.gsfc.nasa.gov/planetary/ice/ice_mercury.html
Chao Meng-Fu - a 167 kilometerdiameter crater on Mercury located
near the south pole.
MESSENGER Mission to
Mercury
• A very important study of a poorly-known planet
• A great challenge for scientists and engineers
• An extremely exciting mission to follow by
students, educators, public in general!
Contact Info
Heather Weir
301-867-2083
[email protected]
Tell me and I forget
Show me and I remember
Involve me and I understand
Chinese Proverb
Exploring Ice in the Solar
System
NASA’s MESSENGER and
Astrobiology group of the Carnegie
Institute of Washington
Exploring Ice in the Solar System
• Educational module on:
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Ice
Properties of ice
What can live in ice.
Where ice can be found
• Grades: Pre K-2 and 3-5
• 12 lessons plus “icebreaker” introduction
Exploring Ice in the Solar System
• Science and literature
• Concept overviews for Pre K-Grade 2 and
Grade 3- Grade 5
• Lesson summary and objectives
• Standards (NSES and Benchmarks)
• Essential question
• Activity question
• Background
• Material
Exploring Ice in the Solar System
• Demonstration for Pre K-Grade 2 and Grade 3Grade 5
• Act-it out (not in all lessons)
• Main Activity
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Preparation
Warm-up and pre-assessment
Procedures
Discussion and reflection
– Curriculum connection
• Assessment criteria
• Resources
Exploring Ice in the Solar System
• Lessons on CD
• Introductory “splash”
page
• Read in adobe acrobat
E/PO Team
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AAAS - American Association for the Advancement of Science
CCSSE- Challenger Center for Space Science Education
CASE - Carnegie Academy for Science Education
JHU/APL - The Johns Hopkins University Applied Physics Laboratory
SSAI - Science Systems and Applications, Inc.
MU-SPIN - Minority University-Space Interdisciplinary Network
CERES - Center for Educational Resources at Montana State University
NASM - National Air and Space Museum
AMNH - American Museum of Natural History in New York
PW - Parmee/Weinrich independent television production/direction team.
MSET - MESSENGER Science and Engineering Team
Theme I
Comparative Planetology
What do we know about our family of planets? What
don’t we know? This theme is an examination of the
diversity of worlds in the Solar System and what is
currently known about Solar System formation and
evolution.
MESSENGER Stories
– What does Mercury tell us about the other planets
in the Solar System?
– What will we learn from MESSENGER
observations?
Theme II
The Solar System Through History
How have we come to know what we know about the
Solar System? This theme is an exploration of the
Solar System through the eyes of, and resources
available to, past generations.
MESSENGER Stories
– Mercury through history - a case study
– How does MESSENGER science and engineering
build from the knowledge of past generations?
Theme III
Framing Pathways to Answers:
The Scientific Process in Action
How do we solve engineering and design problems within
constraints? What is the process of scientific exploration? This
theme is an investigation of the scientific process through the
vantage point of a planetary mission. It also places research and
exploration in a human context.
MESSENGER Stories
– Meeting MESSENGER’s engineering
challenges
– Framing experimental pathways to do
MESSENGER science
– The MESSENGER team
Education Materials
• MESSENGER
Education Modules
(MEMs)
– Broad, content-rich,
overview for teachers
– Inquiry-based, processdriven approaches to
science education
– Diverse array of
activities and materials
contributed by E/PO
partners
– Units for each grade
level (PreK-12)
– Updated throughout the
mission
http://btc.montana.edu/messenger/main/epo.php
Dissemination
• Educator Training and Workshops
– MESSENGER Fellowship program
– **Journey through the Universe**
– NASA Educators Workshops
– MU-SPIN Educators Workshops
– Solar System Ambassadors
• Online
– MSU CERES Project and MESSENGER E/PO
web site
– AAAS Science NetLinks
– Journey through the Universe
Education Modules
Comparative Planetology
The Solar System Through
History
Framing Pathways to
Answers: The Scientific
Process in Action
Voyage
Unit 2
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Unit 1
Unit 2
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Staying
Cool
Unit 2
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Staying Cool
Chapter 1
Chapter 2
Chapter 3
Elementary
School
Lesson
Lesson
Middle School
Lesson
Lesson
Lesson
High School
Lesson
Lesson
Lesson
Staying Cool
How can we
study Mercury?
Elementary
School
Middle School
High School
Are there any
problems we
might face?
Sensing Energy
Are there ways
to solve these
problems?
Cooler in the
Shadows
Sensing the
Invisible – The
Herschel
Experiment
Snow Goggles
and Limiting
Sunlight
My Angle on
Cooling – Effect
of Distance and
Inclination
Star Power! –
Discovering the
Power of Sunlight
Dangers of
Radiation
Exposure
Cooling with
Sunshades
How can we study Mercury?
• Sensing Energy (Grades 2-4)
– Students use UV-sensitive beads to discover that
ultraviolet light comes from the Sun, but that there are
ways we can protect ourselves from it
– National Science Education Standards D2, A2, B8
How can we study Mercury?
• Sensing the Invisible –
The Herschel Experiment
(Grades 5-8)
– Students re-create Sir
William Herschel’s
experiment of 1800 and
discover that infrared light
comes from the Sun.
– Students examine why
infrared radiation is
important
– National Science Education
Standard B3
– AAAS Benchmarks 4F, 12C
How can we study Mercury?
• Star Power! Discovering
the Power of Sunlight
– Students calculate the
solar constant on Earth
and compare it to what
it would be at Mercury
– National Science
Education Standards
B6, D1
– AAAS Benchmark 4E
Are there any problems?
• Snow Goggles and Limiting
Sunlight (Grades 5-8)
– Students measure their fieldof-view with and without snow
goggles
– Students discuss how
MESSENGER uses similar
approaches to limit its
exposure to sunlight (but they
both use the scientific
method)
– National Science Education
Standards A1, A2
– AAAS Benchmarks 4F, 11B,
12C
Are there any problems?
• Dangers of Radiation
Exposure (Grades 9-12)
– Students calculate
yearly radiation
exposure
– Compare exposure rate
on Earth with that of
Mercury
– Examine MESSENGER
mission in terms of solar
cycle
– National Science
Education Standard F5
– AAAS Benchmarks
10G, 1C
Are there ways to solve them?
• Cooler in the Shadows
(Grades PreK-1)
– Students monitor
shadows throughout the
day to see how they
change
– Temperatures taken in
and out of the shadows,
and show that it really is
cooler in the shadows
– National Science
Education Standards
D2, B1
– AAAS Benchmark 4E
Are there ways to solve them?
• My Angle on Cooling –
Effect of Distance and
Inclination (Grades 5-8)
– Students discover how
temperature changes as
a function of distance
and inclination
– Discuss cause of the
seasons on Earth
– Discuss how
MESSENGER uses
these tactics
– National Science
Education Standard D3
– AAAS Benchmark 12C
Are there ways to solve them?
• Cooling with Sunshades
(Grades 9-12)
– Students design a
sunshade to keep ice
from melting
– Re-design, eliminate
sources of error
– National Science
Education Standard B5
– AAAS Benchmarks 4E,
8B
Design Challenges
• Grades PreK-1
– What Will Keep My
Lunchbox Cool?
• Grades 2-4
– How Do You Prevent
Things from Getting Too
Hot?
• Grades 5-8
– How yo Keep Gelatin
from Melting?
• Grades 9-12
– How yo Keep Items
Cool in Boiling Water?
Challenger Center Pedagogy
• Challenger Center creates inquiry-based hands-on lessons in which
students are at the center, creating their own knowledge.
• Lessons are created by a team of educators and practicing
researchers, to ensure high-quality materials that are scientifically
accurate.
• Challenger Center begins creating lessons based on the National
Science Education Standards they want to address, not simply
aligning lesson as an after-thought.
Snow Goggles
Sun
Sunglasses
Hunters
SITUATION:
Imagine that you are a
19th century hunter, trying
to spear a seal on the
arctic ice in springtime to
feed your family. Near
the North Pole, where
everything is covered by
snow and ice, it is bright
in all directions. There is
so much light and glare
from the sky and reflected
from the snow-covered
ground, that you can
become snow blind.
PROBLEM
How do you get rid of the excess light
you do not need, but keep the light
you do, so that you can still see the
seals (and so that you don’t
accidentally bump into a polar bear)?
• Cut out snow goggles
– Cardstock
– Decorate
• Measure field of view
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without goggles
Measure field of view with
goggles
– Vertical
– Horizontal
Standards & Benchmarks
Standards & Benchmarks PreK-4
Standards & Benchmarks 5-8
Standards & Benchmarks 9-12
Staying Cool Review
• AAAS Review
– High marks
• NASA’s Science Mission Directorate
– Reviewed by four educators and three researchers
» 1 “Good”
» 1 “Very Good”
» 5 “Outstanding”