Australian Centre for Space Photonics Andrew Mc Grath

Australian Centre for Space Photonics Andrew Mc. Grath Anglo-Australian Observatory

This Presentation l Interplanetary communications problem l Long term solution l Historical Australian involvement l Further Australian involvement l Making it happen

Exploration of Mars l Highlights the communications problem l Long term and substantial past and continuing international investment

Exploration of Mars l l l l l 1960 Two Soviet flyby attempts 1962 Two more Soviet flyby attempts, Mars 1 1964 Mariner 3, Zond 2 1965 Mariner 4 (first flyby images) 1969 Mariners 6 and 7 1971 Mariners 8 and 9 1971 Kosmos 419, Mars 2 & 3 1973 Mars 4, 5, 6 & 7 (first landers) 1975 Viking 1, 1976 Viking 2

Exploration of Mars l l l l 1988 Phobos 1 and 2 1992 Mars Observer 1996 Mars 96 1997 Mars Pathfinder, Mars Global Surveyor 1998 Nozomi 1999 Climate Orbiter, Polar Lander and Deep Space 2 2001 Mars Odyssey

Planned Mars Exploration l l l 2003 Mars Express 2004 Mars Exploration Rovers 2005 Mars Reconnaissance Orbiter 2007+ Scout Missions 2007 2009 Smart Lander, Long Range Rover 2014 Sample Return

Interplanetary Communication l Radio (microwave) links, spacecraft to Earth l Newer philosophy - communications relay (Mars Odyssey, MGS) l Sensible network topology l 25 -W X-band (Ka-band experimental) <100 kbps downlink

Communications Bottleneck l Current missions capable of collecting much more data than downlink capabilities (2000%!) l Currently planned missions make the problem 10 x worse l Future missions likely to collect evergreater volumes of data

Communications Bottleneck l Increasing downlink rates critical to continued investment in planetary exploration

Communications Bottleneck l NASA's perception of the problem is such that they are considering an array of 3600 twelve-metre dishes to accommodate currently foreseen communications needs for Mars alone

Communications Energy Budget Consider cost of communications reduced to transmitted energy per bit of information received

Communications Energy Budget Assumptions: • information proportional to number of photons (say, 10 photons per bit) • diffraction-limited transmission so energy density at receiver proportional to ( R/DT)-2 • received power proportional to DR 2 • photon energy hc / So: Cost proportional to R 2 / (DT 2 DR 2)

Communications Energy Budget Cost proportional to R 2 / (DT 2 DR 2) X-band transmitter ~ 40 mm Laser transmitter ~ 0. 5 -1. 5 m Assuming similar aperture sizes and efficiencies, optical wins over microwave by > 3 orders of magnitude

Long-term Solution l Optical communications networks l Advantages over radio l Higher modulation rates l More directed energy l Analagous to fibre optics vs. copper cables

Lasers in Space l Laser transmitter in Martian orbit with large aperture telescope l Receiving telescope on or near Earth l Preliminary investigations suggest ~100 Mbps achievable on 10 to 20 year timescale l Enabling technologies require accelerated development

Key Technologies l Suitable lasers l Telescope tracking and guiding l Optical detectors l Cost-effective large-aperture telescopes l Atmospheric properties l Space-borne telescopes

An Australian Role - till now l History of involvement l Launch sites l Development of early satellites l Communications – Deep Space Network – Parkes, ATNF – Continuing involvement

An Australian Role - in the future l Australian organisations have unique capabilities in the key technologies required for deep space optical communications links High-power, high beam quality lasers l Holographic correction of large telescopes l Telescope-based instrumentation l Telescope tracking and guiding l

The University of Adelaide l Optics Group, Department of Physics and Mathematical Physics – High power, high beam quality, scalable laser transmitter technology – Holographic mirror correction – Presently developing high power lasers and techniques for high optical power interferometry for the US Advanced LIGO detectors

Anglo-Australian Observatory l Telescope technology l Pointing and tracking systems l Atmospheric transmission (seeing, refraction) l Cryogenic and low noise detectors l Narrowband filter technology

Macquarie University l Centre for Lasers and Applications – Optical communications – Transmitter technology

A Proposal l Use the ARC 'Centre of Excellence' programme to link these organisations to capitalise on Australia's strategic advantages to become an indispensable partner in the world-wide scientific space exploration effort

Australian Centre for Space Photonics l To expand unique Australian capabilities and experience to progress research into key technologies for an interplanetary high-data rate optical communications link that are synergistic with near term space communication needs.

Australian Centre for Space Photonics l Manage a portfolio of research projects in the key technologies for an interplanetary optical communications link l Work in close collaboration with overseas organizations such as NASA and JPL

Australian Centre for Space Photonics l An Australian foothold into the wellestablished `big science' investment of the leading space agencies

Australian Centre for Space Photonics l Closer ties to leading space agencies and their current and planned missions

Australian Centre for Space Photonics l Australia's continued long term participation in the Deep Space Network

Australian Centre for Space Photonics l Attract and retain the best Australian students and staff in optics and photonics

Australian Centre for Space Photonics l Creation of photonics and space technology IP for commercial development

Australian Centre for Space Photonics l Take advantage of unique Australian capabilities l Australian technology becomes critical to deep space missions l Continued important role in space FOR MORE INFO. . . http: //www. aao. gov. au/lasers