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Exploring the Lunar Environment

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Exploring the Lunar Environment with the Lunar Atmosphere and Dust Environment Explorer South Bay Amateur Radio Association February 8, 2013 – PowerPoint PPT presentation

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Title: Exploring the Lunar Environment


1
Exploring the Lunar Environment with the Lunar
Atmosphere and Dust Environment Explorer South
Bay Amateur Radio Association February 8,
2013 Brian Day LADEE Mission E/PO Lead NASA Lunar
Science Institute Director of Communication and
Outreach Brian.H.Day_at_nasa.gov
2
A new generation of robotic lunar explorers is
revolutionizing our understanding of the Moon.
We now recognize the Moon as a dynamic world with
surficial and internal volatiles, active
geology, and complex interactions with space
weather. All of these could contribute to a
fascinating lunar atmospheric environment.
3
LRO and LCROSS
Lunar Crater Observation and Sensing
Satellite LCROSS
Lunar Reconnaissance Orbiter LRO
4
  • LRO and LCROSS launched together on an Atlas V
    rocket from Cape Canaveral on June 18, 2009.

5
LCROSS Mission Concept
  • Impact the Moon at 2.5 km/sec with a Centaur
    upper stage and create an ejecta cloud that may
    reach over 10 km about the surface
  • Observe the impact and ejecta with instruments
    that can detect water

6
What did we see?
7
What did we see?
What did we see?
Schultz, et al (2010)
Cam1_W0000_T3460421m473
(Observed expanded ejecta cloud 10-12 km in
diameter at 20s after impact. Visible camera
imaged curtain at t8s through t42s, before
cloud dropped below sensitivity range).
8
What did we see?
What did we see?
9
Water Signatures Detected!
10
Lunar Reconnaissance Orbiter (LRO)
  • LROC image and map the lunar surface in
    unprecedented detail
  • LOLA provide precise global lunar topographic
    data through laser altimetry
  • LAMP remotely probe the Moons permanently
    shadowed regions
  • CRaTER - characterize the global lunar radiation
    environment
  • DIVINER measure lunar surface temperatures
    map compositional variations
  • LEND measure neutron flux to study hydrogen
    concentrations in lunar soil

11
Apollo 14 Landing Site Imaged by LRO
On the right, you can see the descent stage of
the lunar module which carried the astronauts
down to the surface of the Moon. On the left,
the arrow points to an instrument package with
experiments left on the Moon by the
astronauts. In between you can see some dark
squiggly lines the footprints of the astronauts.
12
You Can Help Explore the Moon!
Visit http//cosmoquest.org/mappers/moon/
and http//www.moonzoo.org/ to see how you can
help explore the images from LRO.
13
The Moons Permanently Shadowed Craters are the
Coldest Places We have Found in the Solar System
  • LRO has measured temperatures as low as -248
    degrees Celsius, or -415 degrees Fahrenheit
  • This is colder than the daytime surface of Pluto!
    (-230 Celsius)

14
LROs DIVINER Indicates Widespread Ice at Lunar
Poles
  • In South Pole permanently-shadowed craters,
    surface deposits of water ice would almost
    certainly be stable.
  • These areas are surrounded by much larger
    permafrost regions where ice could be stable just
    beneath the surface.

15
Water in the Soil
  • Chandrayann-1 and two other robot explorers found
    small amounts of water away from the poles.

Deep Impact
Cassini
Chandrayaan-1
16
Lobate Scarps The Shrinking Moon
17
Moonquakes A Whole Lot of Shaking Going On
  • Deep moonquakes about 700 km below the surface,
    probably caused by tides.
  • Vibrations from the impact of meteorites.
  • Thermal quakes caused by the expansion of the
    frigid crust when first illuminated.
  • Shallow moonquakes 20 or 30 kilometers below the
    surface. Up to magnitude 5.5 and over 10
    minutes duration!

18
Gravity Recovery and Interior Laboratory GRAIL
  • Launched Sept 10, 2011. Mission completed
    December 17, 2012.
  • Microwave ranging system precisely measures the
    distance between the two satellites.
  • Use high-quality gravity field mapping to
    determine the Moon's interior structure.
  • Determine the structure of the lunar interior,
    from crust to core and to advance understanding
    of the thermal evolution of the Moon.

19
ARTEMIS
  • Acceleration, Reconnection, Turbulence and
    Electrodynamics of the Moons Interaction with
    the Sun
  • Consists of two orbiters, ARTEMIS-P1 ARTEMIS
    P2, formerly part of the THEMIS mission.
  • Moved to lunar L1 and L2 points in 2010 and
    lunar orbit in 2011.
  • Studying the solar wind and its interaction with
    the lunar surface, the Moons plasma wake, and
    the Earths magnetotail.

20
  • Mission is studying how solar wind electrifies,
    alters and erodes the Moon's surface.
  • The Moon exhibits a long comet-like sodium tail.
  • The Earth passes through this tail once a month.
  • Similarly, the Earths exospheric tail extends
    beyond the Moons orbit.
  • Could provide valuable clues to the origin of the
    lunar atmosphere.

21
Lunar Atmosphere?
  • Yes, but very thin! A cubic centimeter of Earth's
    atmosphere at sea level contains about 1019
    molecules. That same volume just above the Moon's
    surface contains only about 100,000 to a few
    million molecules.
  • It glows most strongly from atoms of sodium.
    However, that is probably a minor constituent. We
    still do not know its composition.

22
Lunar Exosphere
  • An exospheres is a tenuous, collisionless
    atmosphere.
  • The lunar exosphere is bounded by the lunar
    surface a surface boundary exosphere.
  • Consists of a variety of atomic and molecular
    species indicative of conditions at the Moon
    (surface, subsurface).
  • Wide variety of processes contribute to sources,
    variability, losses.

23
A Dusty Lunar Sky?
In 1968, NASA's Surveyor 7 moon lander
photographed a strange "horizon glow" looking
toward the daylight terminator. Observations are
consistent with sunlight scattered from
electrically-charged moondust floating just above
the lunar surface.
24
A Dusty Lunar Sky?
More possible evidence for dust came from the
Apollo missions.
25
The Lunar Exosphere and Dust Sources Sinks
Inputs Solar photons Solar Energetic
Particles Solar wind Meteoric influx Large
impacts
Dayside UV-driven photoemission, 10s
V Nightside electron-driven negative
charging -1000s V
Processes Impact vaporization Interior
outgassing Chemical/thermal release
Photon-stimulated desorption Sputtering

26
Lunar Exosphere
Cold-trapping in Polar regions
Formation of Lunar volatiles
Vondrak and Crider, 2003
Mendillo et al, 1997
Stern, 1999Smyth and Marconi, 1995
27
Exospheres and Dust
Surface Boundary Exospheres (SBEs) may be the
most common type of atmosphere in the solar
system
Large Asteroids KBOs
Mercury
Moon
Evidence of dust motion on Eros and the Moon....
Europa other Icy satellites
Io
Eros
Delory, American Geophysical Union Fall Meeting
12-16-09
28
LADEE
The Lunar Atmosphere and Dust Environment Explorer
  • Determine the global density, composition, and
    time variability of the fragile lunar atmosphere
    before it is perturbed by further human
    activity.
  • Determine the size, charge, and spatial
    distribution of electrostatically transported
    dust grains.
  • Test laser communication capabilities.
  • Demonstrate a low-cost lunar mission
  • Simple multi-mission modular bus design
  • Low-cost launch vehicle

29
Neutral Mass Spectrometer (NMS) MSL/SAM Heritage
UV Spectrometer (UVS) LCROSS heritage
SMD - directed instrument
SMD - directed instrument
In situ measurement of exospheric species P.
Mahaffy NASA GSFC
Dust and exosphere measurements A.
Colaprete NASA ARC
150 Dalton range/unit mass resolution
Lunar Dust EXperiment (LDEX) HEOS 2, Galileo,
Ulysses and Cassini Heritage
Lunar Laser Com Demo (LLCD) Technology
demonstration
SOMD - directed instrument
SMD - Competed instrument
High Data Rate Optical Comm D. Boroson MIT-LL
M. Horányi, LASP
51-622 Mbps
30
Spacecraft Configuration
  • 330 kg spacecraft mass
  • 53 kg payload mass

31
LADEE Mission Profile
  • Launch in 2013 from Wallops as the first
    payload to fly on the new Minotaur V launch
    vehicle.
  • 2-3 phasing orbits to get to Moon.
  • Insertion into retrograde orbit around Moon.
  • Checkout orbit (initially 250km) for 30
    days.
  • 100-day science mission at 20- 75km.

32
LADEE and Lunar Impacts
  • NASA Meteoroid Environment Office
  • Lunar Impact Monitoring Program
  • Help lunar scientists determine the rate of
    meteoroid impacts on the Moon.
  • Meteoroid impacts are an important source for
    the lunar exosphere and dust.
  • Can be done with a telescope as small as 8
    inches of aperture.
  • Also to working with AAVSO Lunar Meteoritic
    Impact Search Section.

33
Provide Background Science Data LADEE and Lunar
Impacts
Confirmed Lunar Impact March 13, 2008 020421UT
by George Varos
34
  • Phase Matters
  • Impact flashes are observed in the unilluminated
    area of the Moon.
  • Near 1st Qtr, the Moons leading hemisphere faces
    Earth generally best for observing impact
    flashes.
  • Near 3rd Qtr, the Moons trailing hemisphere
    faces Earth generally less favorable for
    observing impact flashes.
  • A large gibbous phase results in lots of glare
    from illuminated lunar surface, small
    unilluminated area for observing flashes, and
    diminished Earth shine on unilluminated area
    making localizing impacts difficult.
  • Thin crescent phase results in restricted
    observing time in dark sky.

35
  • Lunar Meteoroid Impact Monitoring
  • Minimum System Requirements
  • 8" telescope
  • 1m effective focal length
  • Equatorial mount or derotator
  • Tracking at lunar rate
  • Astronomical video camera with adapter to fit
    telescope
  • NTSC or PAL
  • 1/2" detector
  • Digitizer - for digitizing video and creating a
    720x480 .avi
  • Segment .avi to files less than 1GB (8000 frames)
  • Time encoder/signal
  • GPS timestamp or WWV audio
  • PC compatible computer
  • 500GB free disk space
  • Software for detecting flashes
  • LunarScan software available as a free download

36
  • Meteor Counting
  • The vast majority of meteoroids impacting the
    Moon are too small to be observable from
    Earth.
  • Small meteoroids encountering the Earths
    atmosphere can result in readily-observable
    meteors.
  • Conducting counts of meteors during the LADEE
    mission will allow us to make inferences as to
    what is happening on the Moon at that time.
  • Much more simple requirements a dark sky, your
    eyes, and log sheet. (a reclining lawn chair
    is very nice too!)
  • International Meteor Organization
    (http//imo.net/)
  • American Meteor Society (http//www.amsmeteors.org
    /)

Image creditNASA/ISAS/Shinsuke Abe and Hajime
Yano
37
Now for Android too!
38
Lunar Phases for Major Meteor Showers During
Projected LADEE Mission Timeframe Aug 12 2013
Perseids Waxing Crescent 35 Oct 21 2013
Orionids Waning Gibbous 90 Nov 19 2013
Leonids Waning Gibbous 94 Dec 14 2013
Geminids Waxing Gibbous 95 Dec 22 2013
Ursids Waning Gibbous 73 Jan 4
2014 Quadrantids Waxing Crescent 13
Lunar Phase Aug 12, 2013
39
Radio Observations of Meteors
  • Meteors produce a column of ionized gas as they
    pass through the atmosphere.
  • This column reflects radio waves from
    transmitters on Earths surface.
  • The columns of ionized gas created by meteors
    usually last for only a fraction of a second.
  • Brighter meteors can produce columns that last
    for several seconds.
  • Traditionally, VHF frequencies between 40-60 MHz
    have been used.
  • Frequencies at low end of the FM band between
    88-104 MHz are also useful.
  • Most radio systems used for meteor detection are
    of the forward scatter type.

40
Radio Observations of Meteors
  • Radio observations provide the only way to
    measure activity from daytime meteor showers.
  • Radio observations have fewer constraints imposed
    by clouds and light pollution (both man-made and
    arising from fuller lunar phases).
  • Observations are preferentially made in the hours
    proceeding from midnight to noon.

41
Daytime Meteor Showers
Shower Activity Period Maximum Capricornids/Sagi
ttariids 1/15-2/4 2-Feb Chi Capricornids
1/29-2/28 14-Feb April Piscids 4/8/-4/29
20-Apr Delta Piscids 4/24-4/24 24-Apr Epsilon
Arietids 4/24-5/27 9-May May Arietids
5/4-6/6 16-May Omicron Cetids 5/5-6/2
20-May Arietids 5/22-7/02 7-Jun Zeta
Persieds 5/20-7/5 9-Jun Beta Taurids
6/5-7/17 28-Jun Gamma Leonids 8/14-9/12
25-Aug Sextantids 9/9-10/9 27-Sep
42
Example MSFC Forward Scatter Meteor Radar
  • Antenna 6-element Yagi commercially available
    cut-to-frequency channel 4 TV antenna
  • Antenna orientation Sits on the ground, pointed
    straight up
  • Receiver ICOM PCR-1000 receiver
  • Receiver Settings The CW demodulator is used so
    that 67.250 MHz (channel 4 zero offset) appears
    at about 700 Hz. This also inverts the passband
    so that the doppler shift of meteor echoes is
    reversed (frequency increases rather than
    decreases to the 'zero' frequency of the trail
    echo). The filter is set to 3 kHz bandwidth and
    the AGC is turned off.

43
Example MSFC Forward Scatter Meteor Radar
Local Channel 4 zero offset TV transmitters with
a circle around each showing the areas they
illuminate down to an altitude of 100 km (typical
meteor altitude). Although the transmitters are
over the horizon for MSFC on the ground, a meteor
at 100 km above MSFC has a direct line of sight.
System was detecting 2,000 pings per day.
44
System Requirements
  • General coverage radio receiver capable of tuning
    TV channels 2-6 (54-88 MHz) with CW or SSB
    demodulator
  • Antenna Commercial TV antenna or
    build-it-yourself
  • PC compatible computer w/sound card
  • Required cabling
  • Fast Fourier Transform and Meteor Counting
    Software
  • Receiver The only real requirement is that you
    can tune to 54-88 MHz and demodulate a SSB
    (single side band) or CW (continuous wave or
    Morse code) signal.
  • Antenna A simple 2 element Yagi antenna provides
    the best gain/field of view combination but have
    also used a higher gain 6 element
    cut-to-frequency commercial TV antenna. A good
    compromise is a VHF or VHF/UHF multi-element TV
    antenna like those available from Radio Shack.

45
Challenges
  • Fewer appropriate VHF transmitters available with
    demise on analog TV broadcasting.
  • In many areas in the U.S., tuning to an empty
    frequency can be challenging.
  • Ideal VHF window for meteor detection of 25-60
    MHz is being impinged upon by increasing solar
    activity, with ionospheric bounce increasing as
    exhibited by reflections up to and beyond 30 MHz.

46
PSK2k A Meteor Scatter Solution?
  • High speed meteor scatter software written by
    Klaus von der Heide (Hamburg University).
  • Instead of needing a TV transmitter or beacon,
    works with 2 or more amateurs using mutual
    frequency and any suitable transceiver/PC/soundcar
    d combination.
  • Can be operated in fully automatic mode if
    required. This enables QSOs to be completed
    automatically without user intervention.
  • Works with hardware commonly in use by amateurs.
  • Provides an extra human element with
    collaboration between individuals.
  • Questions
  • How usable is this software by visually-impaired
    operators?
  • Are there alternative solutions we should be
    looking at?

47
Opportunities
  • Gather data that could be useful to the LADEE
    mission and lunar science.
  • Improve understanding of poorly characterized
    daytime meteor streams.
  • Provide enhanced capabilities for U.S.
    participation in this area of research, building
    upon experience of Japanese and Dutch networks.
  • Leverage the interest in NASA space exploration
    to attract more people to amateur radio.
  • Excellent opportunity for student engagement.
  • High-profile opportunity to engage students at
    the California School for the Blind and members
    of the National Federation for the Blind.

48
Questions
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