Exploring the Lunar Environment with the Lunar Atmosphere and Dust Environment Explorer

1. Exploring the Lunar Environment with the Lunar Atmosphere and Dust Environment Explorer South Bay Amateur Radio Association – February 8, 2013 Brian DayLADEE Mission E/PO Lead NASA Lunar Science Institute Director of Communication and Outreach Brian.H.Day@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 t+8s through t+42s, 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 Moon’s 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 Moon’s 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. LRO’s 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 LaboratoryGRAIL • 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 Moon’s 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 Moon’s plasma wake, and the Earth’s 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 Earth’s exospheric tail extends beyond the Moon’s 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 exosphere’s 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, 1999;Smyth 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 02:04:21UT by George Varos

34. Phase Matters • Impact flashes are observed in the unilluminated area of the Moon. • Near 1st Qtr, the Moon’s leading hemisphere faces Earth – generally best for observing impact flashes. • Near 3rd Qtr, the Moon’s 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 Earth’s 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 credit:NASA/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 Earth’s 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 ShowerActivity PeriodMaximum Capricornids/Sagittariids 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/soundcard combination. • Can be operated in fully automatic mode if required. This enables QSO’s 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