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SPIDAR: VLF Astronomy on the Moon Jodi Y. Enomoto University of Southern California ASTE SPIDAR: VLF Astronomy on the Moon Jodi Y. Enomoto University of Southern California ASTE 527: Space Exploration Architectures Concept Synthesis Studio December 15, 2008

Contents • Context and Rational • VLF Astronomy – A New View of the Contents • Context and Rational • VLF Astronomy – A New View of the Universe – Why do we need the Moon? • South Pole Observatories – – SPIDAR (South Pole Isolated Dipole ARray) Optical Interferometer Heliograph Infrared Interferometer • Further Studies & Future Missions Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Context • Mission Statement: 1. Return humans to the Moon for reliably advancing and Context • Mission Statement: 1. Return humans to the Moon for reliably advancing and honing Mars Forward technologies and experience. 2. In the process, establish “permanent science assets” with ASAP returns for all of humanity. • This presentation mainly focuses on the 2 nd priority. – Astronomers are a large and active Origins and “lunar science from the Moon” community. – How to deploy, calibrate and commission a variety of science payloads, using crew, as well as their preferred locations spread out globally. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Rationale • “Astronomy may not be the reason to go to the Moon, but Rationale • “Astronomy may not be the reason to go to the Moon, but it is definitely something we can do that would be beneficial to the scientific community and humanity as a whole. ” Dec 15, 2008 SPIDAR Jodi Y. Enomoto

VLF Astronomy: A New View of the Universe • What will we find? • VLF Astronomy: A New View of the Universe • What will we find? • New phenomenon, objects… • Low frequency SETI? Dec 15, 2008 SPIDAR Jodi Y. Enomoto

VLF Astronomy: Why do we need the Moon? • Used as a shield – VLF Astronomy: Why do we need the Moon? • Used as a shield – The Sun – Solar Wind, Solar Flares, Coronal Mass Ejections • Large stable platform – Interferometers with very long baselines – No propellants or thrusters necessary for positioning or formation flying Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Observatory Locations Future Missions = Observatory North Pole Observatory: Peary Crater Mid Latitude Observatory: Observatory Locations Future Missions = Observatory North Pole Observatory: Peary Crater Mid Latitude Observatory: Grimaldi Basin (East Side, View from Earth) Far Side Observatory: Daedalus or Tsiolkovsky Crater South Pole Observatories: Mons Malapert, Shackleton Crater, Schrodinger Basin Dec 15, 2008 SPIDAR Jodi Y. Enomoto

South Pole Observatories Mons Malapert Shackleton Schrodinger Dec 15, 2008 SPIDAR Jodi Y. Enomoto South Pole Observatories Mons Malapert Shackleton Schrodinger Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Schrodinger Basin: SPIDAR Observatory Transmit to Lunar Base Station Dipoles Supporting Cables SPIDAR South Schrodinger Basin: SPIDAR Observatory Transmit to Lunar Base Station Dipoles Supporting Cables SPIDAR South Pole Isolated “Anchors” Dipole ARray Communication & Power Rover + Crossbow 5 km eter am Di Length = 50 x Dec 15, 2008 SPIDAR Jodi Y. Enomoto

SPIDAR Observatory A Curved (Hanging Parabola) Geometry SPIDAR Allowing some slack the lines would SPIDAR Observatory A Curved (Hanging Parabola) Geometry SPIDAR Allowing some slack the lines would South Pole make it more feasible to achieve an array Isolated with a MUCH longer baseline Dipole ARray Communication & Power Rover + ABE’s eter am i D 0 km 5 Length = 500 x “ABE” = Artillery Based Explorer Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Schrodinger Basin: SPIDAR Observatory SPIDAR System Parameters Site Dipoles Schrodinger Basin Supporting Cables 1 Schrodinger Basin: SPIDAR Observatory SPIDAR System Parameters Site Dipoles Schrodinger Basin Supporting Cables 1 MHz Frequency Wavelength “Anchors” λ = 300 m Dipole Spacing λ/2 = 150 m Communication Number of Elements & Power 500 Aperture 5 km Bandwidth ~100 k. Hz Resolution TBD Lifetime 20+ years Weight (Earth value) Rover + Crossbow Array < 1000 kg eter < 50 kg Diam m Anchors 5 k Length = 50 x Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Possible Location for SPIDAR: Schrodinger Lava Tube Dark-Halo Crater on the Floor of Schrödinger Possible Location for SPIDAR: Schrodinger Lava Tube Dark-Halo Crater on the Floor of Schrödinger Basin Located at 76°S, 139°E 5 kilometers across is a volcanic vent that erupted ash during the period of mare volcanism on the Moon, more than 3. 5 billion years ago. http: //www. lpi. usra. edu/publications/slidesets/clem 2 nd/slide_4. html 5 km High Resolution Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Assumptions • 14 Lunar surface days. • Astronauts will assist emplacement of the array Assumptions • 14 Lunar surface days. • Astronauts will assist emplacement of the array on the lunar surface. – Rovers, Tele-Operations, etc. • Power and communication infrastructure is established prior to the observatory • Lunar libration is accurately accounted for with software algorithms. • Diurnal temperature variation considerations. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Emplacement of the Array • Raytheon TOW (Tube-launched, Optically-tracked, Wire-guided) Weapon System Technology Simple, Emplacement of the Array • Raytheon TOW (Tube-launched, Optically-tracked, Wire-guided) Weapon System Technology Simple, straight forward approach: Shoot a line across the crater, secure it, and pull the array across. Pneumatics and (reusable) spring launchers with crossbows. Fine adjustments: Use a laser (pointing) system to indicate desired emplacement points for the array. • • Dec 15, 2008 After the lines are shot across the distance of the crater, astronauts can make fine adjustments to the final placement. SPIDAR Jodi Y. Enomoto

Calibration of the Array • Inertial Measurement Units and Star Trackers (with accurate star Calibration of the Array • Inertial Measurement Units and Star Trackers (with accurate star maps) to accurately estimate the position (orientation and curvature) of the array – Curve fitting of each line array – Interpolate / Extrapolate each element position • Using laser range finders to get several accurate measurements along each line Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Calibration • Inertial Measurement Units and Star Trackers (with accurate star maps) to accurately Calibration • Inertial Measurement Units and Star Trackers (with accurate star maps) to accurately estimate the position (orientation and curvature) of the array • • • Dec 15, 2008 Curve fitting of each line array Interpolate / Extrapolate each element position Using laser range finders to get several accurate measurements along each line. SPIDAR Jodi Y. Enomoto

Mons Malapert: Optical Interferometer • Meets the objectives and requirements of the 2005 ESAS Mons Malapert: Optical Interferometer • Meets the objectives and requirements of the 2005 ESAS report. – Location: Longitude 0 degrees, latitude 86 degrees S – Continuous LOS to Earth for communications link capability – Summit is a large, relatively flat landing area • 50 km in its east-west dimension • Optical Interferometer placed on Mons Malapert – 3 or more observatories placed 1 km or more apart – Resolution of milli-arc-seconds to micro-arc-seconds Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Mons Malapert: Optical Interferometer http: //www. sciencecodex. com/graphics/Altair_Comp. jpg Dec 15, 2008 SPIDAR Jodi Mons Malapert: Optical Interferometer http: //www. sciencecodex. com/graphics/Altair_Comp. jpg Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Space Interferometry Mission: Search for Extrasolar Planets http: //en. wikipedia. org/wiki/Space_Interferometry_Mission Dec 15, 2008 Space Interferometry Mission: Search for Extrasolar Planets http: //en. wikipedia. org/wiki/Space_Interferometry_Mission Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Shackleton Crater: Heliograph & Infrared Interferometer • Peak of eternal light Heliograph, Solar Observation Shackleton Crater: Heliograph & Infrared Interferometer • Peak of eternal light Heliograph, Solar Observation • Crater of eternal darkness and extremely low temperatures Infrared Interferometer • ILOA (International Lunar Observatory Association): Planning 3 missions to the Moon – – ILO-X (Precursor) ILO-1 (Polar Mission) ILOA’s Human Service Mission Mons Malapert and Shackleton Crater Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Future Studies… • SPIDAR baseline aperture – Increased for higher resolution capability • Artillery Future Studies… • SPIDAR baseline aperture – Increased for higher resolution capability • Artillery Based Explorers (ABE’s) for array emplacement (towed lines) – Up to 10 km (accurate) range • Calibration of the array – Accuracy requirements • Timeline – Latest ESAS document specifies 14 -day missions – Limits the amount of time on the lunar surface to ~4 days Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Future Missions… A Phased Approach • Early Missions: – Seismic activity study – UV, Future Missions… A Phased Approach • Early Missions: – Seismic activity study – UV, Visible and Infra-red (IR) • Future Missions with a Permanent Lunar Base: – Observation extra-solar planets, environment, surface – Very long wavelength radio astronomy • Giant radio telescopes “carved” out of existing craters on the Moon. – Optical Interferometer • 3 or more observatories spaced 1 km apart. – ISRU and Giant Liquid Mirror Telescopes (50 m) • Spinning lunar regolith in a circular dish to create large parabolic surface. • Impossible without gravity. However, the Moon’s lower gravity provides the opportunity to achieve extremely large scopes. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

References 1. 2. 3. 4. http: //www. iloa. org/media/Moonbase_Mons_Malapert. pdf http: //www. lpi. usra. References 1. 2. 3. 4. http: //www. iloa. org/media/Moonbase_Mons_Malapert. pdf http: //www. lpi. usra. edu/publications/slidesets/clem 2 nd/slide_4. html http: //web. mit. edu/iang/www/pubs/artillery_05. pdf Takahashi, Yuki D. , “New Astronomy From the Moon: A Lunar Based Very Low Frequency Array”, Department of Physics and Astronomy, University of Glasgow, July 2003 5. http: //www. sciencecodex. com/graphics/Altair_Comp. jpg 6. http: //en. wikipedia. org/wiki/Space_Interferometry_Mission Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Reference: • Dec 15, 2008 Jodi Y. Enomoto, has 5 years of experience in Reference: • Dec 15, 2008 Jodi Y. Enomoto, has 5 years of experience in Governmental and Aerospace engineering programs, whose interests include attitude determination and control systems, digital signal processing, and signal processing algorithms for airborne radar systems. She has a B. S. degree in EE with an emphasis on Control Systems from the University of Hawaii, Manoa, and is currently pursuing an M. S. degree in EE with an emphasis on DSP and Communications at the University of Southern California. Her experience related to the contents within this document are almost entirely limited to the research performed while creating this concept in order to fulfill the course requirements of ASTE 527 during the Fall 2008 semester at USC . SPIDAR Jodi Y. Enomoto

BACK-UP SLIDES Dec 15, 2008 SPIDAR Jodi Y. Enomoto BACK-UP SLIDES Dec 15, 2008 SPIDAR Jodi Y. Enomoto

 • VLF Astronomy: – http: //www. ugcs. caltech. edu/~yukimoon/RALF/ – We, humans on • VLF Astronomy: – http: //www. ugcs. caltech. edu/~yukimoon/RALF/ – We, humans on Earth, have essentially never observed the universe at any wavelengths greater than 20 m (frequencies below 15 MHz) because of absorption and scattering by the Earth’s ionosphere. Even at 30 MHz (10 m), ionospheric phase effects limit the interferometry baseline to only 5 km, corresponding to only about 10 arcmin resolution. Observing through this new spectral range will lead to discoveries of new phenomena and new classes of objects. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Abstract Picture SPIDAR South Pole Isolated Dipole ARray Rover + Crossbow Dec 15, 2008 Abstract Picture SPIDAR South Pole Isolated Dipole ARray Rover + Crossbow Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Schrodinger Basin • Low Frequency SETI and Radio Astronomy • SPIDAR (South Pole Isolated Schrodinger Basin • Low Frequency SETI and Radio Astronomy • SPIDAR (South Pole Isolated Dipole ARray) Observatory – Frequencies < 20 MHz Wavelengths > 15 m – High resolution requires huge antenna aperture • ILOM (In-situ Lunar Orientation Measurements) and LLFAST (Lunar Low Frequency Astronomical Observatory) are proposed as plans of astronomical observations on the Moon which should be realized in a future lunar mission. ILOM is a selenodetic mission to study lunar rotational dynamics by direct observations of the lunar physical libration and the free librations from the lunar surface with an accuracy of 1 millisecond of arc in the post-SELENE project. Year-long trajectories of the stars provide information on various components of the physical librations and we will also try to detect the lunar free librations in order to investigate the lunar mantle and the liquid core. The PZT on the moon is similar to that used for the international latitude observations of the Earth is applied. The measurement of the rotation of the Moon is one of the essential technique to obtain the information of the internal structure. The highly accurate observation in the very low frequency band below about 10 MHz is yet to be realized, so that this range is remarkable as one of the last frontiers for astronomy. This is mainly because that the terrestrial ionosphere prevents us from observing the radio waves below the ionospheric cutoff frequency on the ground. It is, moreover, difficult to observe the faint radio waves from planets and celestial objects even on the earth's orbit because of the interference caused by the solar burst, artificial noises and terrestrial aurora emissions. The lunar far-side is a suitable site for the low frequency astronomical observations, because noises from the Earth can always avoided and radio waves from the Sun can be shielded during the lunar night. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Scientific Experiments • Early Missions: – Seismic activity study – UV, Visible and Infra-red Scientific Experiments • Early Missions: – Seismic activity study – UV, Visible and Infra-red (IR) • Future Missions: – Observation of extra-solar planets – Very long wavelength radio astronomy • Giant radio telescopes “carved” out of existing craters on the Moon. – Optical Interferometer • 3 or more observatories spaced 1 km apart. – ISRU and Giant Liquid Mirror Telescopes (50 m) • Spinning lunar regolith in a circular dish to create large parabolic surface. • Impossible without gravity. However, the Moon’s lower gravity provides the opportunity to achieve extremely large scopes. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Limitations / Showstoppers • Moon-quakes – Highly debated. Seismic disturbances were measured over the Limitations / Showstoppers • Moon-quakes – Highly debated. Seismic disturbances were measured over the course of 8 years by the Apollo missions, showing at most 1 disturbance in a given area per year. • Lunar dust Dec 15, 2008 SPIDAR Jodi Y. Enomoto

Effective Aperture Study • Effective aperture of a large pseudorandom low-frequency dipole array Ellingson, Effective Aperture Study • Effective aperture of a large pseudorandom low-frequency dipole array Ellingson, S. W. Antennas and Propagation Society International Symposium, 2007 IEEE Volume , Issue , 9 -15 June 2007 Page(s): 1501 - 1504 Digital Object Identifier 10. 1109/APS. 2007. 4395791 Summary: The long wavelength array (LWA) is a new aperture synthesis radio telescope, now in the design phase, that will operate at frequencies from about 20 MHz to about 80 MHz. This paper describes some preliminary estimates of Ae for such an array. This is a non-trivial problem because the antennas are strongly coupled and interact strongly with the ground. To bound the scope of this preliminary investigation, the antennas are modeled as thin straight half-wave (nearly resonant) dipoles, and we restrict our attention to the co-polarized fields in the principal planes. First, we consider results for a single element in isolation. Next, we consider the results for the entire array, which are compared to the results for the single element and also to the physical aperture of the station. Dec 15, 2008 SPIDAR Jodi Y. Enomoto

History: VLF Array Design Studies 1990’s Dec 15, 2008 SPIDAR Jodi Y. Enomoto History: VLF Array Design Studies 1990’s Dec 15, 2008 SPIDAR Jodi Y. Enomoto

LOFAR; Operational Since 2006 (LOFAR) Low Frequency Array: 10 -240 MHz Dec 15, 2008 LOFAR; Operational Since 2006 (LOFAR) Low Frequency Array: 10 -240 MHz Dec 15, 2008 SPIDAR http: //images. goog le. com/imgres? im gurl=http: //web. mit. edu/annualreport s/pres 02/images/0 3. 05_fig 2. jpg&img refurl=http: //web. mit. edu/annualrep orts/pres 02/03. 05. html&usg=__b 5 R H 0 Z 3 am. Uy. Vz. N_ Gk 58 a 7 Jjo. GHg=& h=354&w=500&sz =59&hl=en&start= 72&um=1&tbnid= 2 detm. LAni. IBN 6 M: &tbnh=92&tbnw=1 30&prev=/images %3 Fq%3 DLOFAR %26 start%3 D 54% 26 ndsp%3 D 18%2 6 um%3 D 1%26 hl %3 Den%26 sa%3 DN Jodi Y. Enomoto