Yuki Takahashi Radio Interferometer Observatory Near the Lunar South Pole Yuki D. Takahashi (U. C. Berkeley) International Lunar Conference International Lunar Exploration Working Group 5 Yuki Takahashi Outline 1.Why Very-Low-Frequency (VLF) Astronomy? 2.Why need the Moon? 3.Making it Happen 4.1st VLF Discovery from the Moon by 2015? Yuki Takahashi Certain things about the Universe we can only learn from the Moon. (impractical from Earth or in free space) - VLF, IR - Yuki Takahashi Very Low Frequency (< 30 MHz) Yuki Takahashi VLF: New View of the Universe New objects, New phenomena => Revolution Where do cosmic rays come from? The most energetic form of matter known. The highest energy phenomena. One of the most fundamental questions still unanswered (since 1912). Interstellar / intergalactic plasma How do galaxies form and evolve? Discover very early radio galaxies Dark matter? Yuki Takahashi Infrared:IRAS 1983 (5 resolution) NASA Yuki Takahashi Infrared:IRAS 1983 (350,000 objects) NASA Yuki Takahashi X-ray:ROSAT (12 resolution / 150,000 objects) NASA Yuki Takahashi Why Need the Moon? Yuki Takahashi Man-made Interference Yuki Takahashi Natural Interference (Sun,Earth,Jupiter) Yuki Takahashi Only from the Moon Yuki Takahashi Brief History of Lunar VLF Effort 1964Gorgolewski 1985A VLF Radio Astronomy Observatory on the Moon (Douglas & Smith) 1988NASA Workshop: A Lunar Far-Side VLF Array JPL Study 1992Hughes Aircraft: ALLFA 1993ISU design project: ILFOSS (Mendell) 1997ESA design study Yuki Takahashi 2002 (Yuki) A Concept for a Simple Radio Observatory at the Lunar South Pole 2002/1 (Gorgolewski) Highest sensitivity radio astronomy and SETI from the far side of the Moon (including crater Saha) 2002/1 (Gorgolewski) Future space VLBI on lunar orbits and the radio shadow on the far side of the Moon 2000/4 (Jones et al) Space VLBI at Low Frequencies 2000 (Woan) Capabilities and Limitations of Long Wavelength Observations from Space 2000 (Kuiper,Jones) Lunar Surface Arrays 2000 (Weiler) The Promise of Long Wavelength Radio Astronomy 2000 (Jones et al) The Astronomical Low Frequency Array: A Proposed Explorer Mission for Radio Astronomy 2000 (Maccone) Laydown of A Tether from Earth Visible Location to Far Side for Lunar SETI 1999 (Woan) A very low frequency radio telescope on the far side of the Moon 1999/2 (Weiler,Jones) Low Frequency Astrophysics from Space (ALFA) 1998 (Weiler) review of radio astronomy from space 1997 (Jones,Weiler) Low Frequency Radio Astronomy From the Moon 1997 Very Low Frequency Array on the Lunar Far Side [ESA SCI(97)2] 1997/3 (Woan) Some design considerations for a Moon-based radio telescope operating at frequencies below 10 MHz (ESA) 1996 (Woan) Design Considerations for a Moon-based Radio Telescope Operating at Frequencies below 16 MHz 1997 (Basart etal) Directions for space-based low-frequency radio astronomy 2. Telescopes 1997 (Basart etal) Directions for space-based low frequency radio astronomy 1. System considerations 1996 (Bougeret) Very Low Frequency Radio Astronomy 1994/6 (Lecacheux) Solar system, low frequency radio astronomy from the Moon 1993 (ISU) International Lunar Farside Observatory and Science Station 1992/5 (Marsh,Mahoney,Kuiper,Jones) Concept for a lunar array for very low frequency radio astronomy 1992/5 (Basart,Burns) Low frequency astronomy from lunar orbit 1992/5 (Duric) Very low frequency radio astronomy from lunar orbit 1992 (Hughes Aircraft Company) Engineering Design of an Unmanned Lunar Radio Observatory 1992 (Hughes Aircraft Company) Telerobotically Deployed Lunar Farside VLF Observatory 1991 (Hughes Aircraft Company) Astronomical lunar low frequency array 1991 (Burns) Aperture synthesis imaging from the moon 1990/4 (Basart,Burns) Initial design of a lunar far-side very low frequency array 1990/2 (Duric,Burns) VLF radio astronomy from the moon - Probing astrophysical plasmas 1990/2 (Kuiper,Jones,Mahoney,Preston) Lunar low-frequency radio array 1990/1 (Kuiper, Jones, Mahoney, Preston) A simple low-cost array on the lunar near-side for the early lunar expeditions 1990/1 (Smith) Very low frequency radio astronomy from the moon 1990/1 (Basart,Burns) A very low frequency array for the lunar far-side 1990/1 (Burns) The Lunar Observer Radio Astronomy Experiment (LORAE) 1990/1 Low Frequency Astrophysics from Space (International Workshop) low frequency astronomy from space 1989 A Lunar Far-Side Very Low Frequency Array (NASA Workshop) [ summary by Douglas ]1988/3 (Burns) MERI: An ultra-long-baseline Moon-Earth radio interferometer 1987 (Burns,Asbell) Radio Astronomy on the Moon 1985 (Burns) A Moon- Earth Radio Interferometer 1985 (Douglas,Smith) A very low frequency radio astronomy observatory on the moon 1978 (Novaco,Brown) Nonthermal galactic emission below 10 megahertz 1975 (Alexander etal) Scientific instrumentation of the Radio-Astronomy-Explorer-2 satellite 1965 (Gorgolewski) Lunar Radio Astronomy Observatory 1964 (Gorgolewski) The Advantages of a Lunar Radio Astronomy Observatory Yuki Takahashi Array of many short dipole antennas All-sky interferometric mapping Tsiolkovsky crater (~100km) Relay sat. at L2 Technically feasible. (Hughes 2000:) 25 cm 2 m Lunar Far Side VLF Array ESA Yuki Takahashi So, how much is it gonna cost? Funding unlikely until far side access becomes easier thru other programs Must come up with a cheap mission for an initial sky survey of the unknown sky. (IR, X-ray) => Get people curious. Yuki Takahashi Cost To save cost: Piggyback on a lunar lander mission. Yuki Takahashi A Proposal To save cost: Piggyback on a lunar lander mission. Antennas: very lightweight. Share communication / power systems. Antennas deposited by rovers. (=> A perfect technology validation project?) Next lunar landers => South Pole Malapert Mountain (Sharpe & Schrunk) Communication relay, Power station, Yuki Takahashi Malapert Mountain can shield interference from Earth 5 km tall 120 km from SP [Margot et al. 1999] Yuki Takahashi Setup 25 cm 2 m Array (linear) 50 elements 1m 3 few100 kg Each element (25 cm) 3 5 kg 1 W Yuki Takahashi Required Measurements to be planned Topography at vertical resolution z = 1/2 m, with spot size x = 10 m. In-situ measurements with dipole receivers: Plasma cut-off frequency Interference levels Observation test Clementine Yuki Takahashi Conservative Timeline Development Design Proposal Launch & Deploy! LOFAR SELENE Yuki Takahashi Summary Very-low-frequency Universe only from the Moon. (impossible from Earth, too noisy in free space) The unknown, VLF radio waves -- especially promising for significant discoveries. VLF interferometer could be set up very cheaply as an excellent technology validation project on a lunar lander mission. Yuki Takahashi Thank you! Wendell Mendell David Schrunk Steve Durst Graham Woan University of Glasgow US-UK Fulbright Commission