A Brief History of Satellite Remote Sensing From Sputnik to Google Earth
Sputnik • Sputnik I Launched by the Soviet Union on October 4, 1957 • Worlds first man-made satellite • Size of a beach ball; Weighed about 184 pounds • Sputnik II launched November 3, 1957 • Carried a dog on board named Laika • U.S. highly shocked and embarrassed by being beaten technologically • Marked the beginning of the US – USSR “space race” • Explorer program begun and successfully launched Explorer I in 1958 (50th anniversary in 2008) • NASA formed (October 1, 1958)
Reaction in U.S. to Sputnik success • “Are they looking down at us??!!” • Flood of students enter engineering schools • A U.S. third grade teacher at a school near a U.S. Air Force Base panics when some American fighter jets fly overhead, shouting “MiGs, MiGs” and runs shrieking from the classroom. (reported in Star Tribune) • Her students, many of whom were Air Force kids admire the U.S. F100’s out the window of their classroom • Politicians criticize our educational system • Ross Perot becomes inspired to enter electronics business
Explorer I • Also called “Satellite 1958 Alpha” • Part of 1957-58 International Geophysical Year • Built by JPL; Designed by William Pickering • Scientific instrumentation designed by James Van Allen • Discovered “Van Allen” belts (belts of charged particles around the earth) • Launch vehicle designed by the Army Ballistic Missile Agency (ABRM) under direction of Wernher Von Braun
TIROS I – Beginning of satellite remote sensing: April 1, 1960 • Television and Infrared Observing Satellite • Polar orbiting • Operated for 79 days; captured more than 72,000 images • Used for meteorology • Crude but groundbreaking – could view earth’s weather as a system; weather satellites now crucial to forecasting, climatology, etc. • Series of TIROS satellites launched through 1965 • Captured first complete view of earth’s weather
Application Technology Satellites – 1966 • Also used for weather remote sensing • ATS-3 (1967) collected first image that showed the whole “disk” of the earth in one view • 3 ATS satellites operational over the next 10 years • Other atmospheric sensing satellites also launched during this time frame (e.g., the Nimbus series) and used for things like atmospheric temperature and ozone profiles.
Geodetic Earth Orbiting Satellite (GEOS) - 1968 • General goal of better control of earth mapping • Pinpointing geodetic control stations in 3D earth coordinate system within 10 meters • Determine structure of earth’s gravitational field • Map gravitational anomalies • Test geodetic remote sensing equipment • Geodesy is the field of study that deals with representing the earth and its gravitational field in 3 dimensions. Central to our spatial representation of the earth’s surface used in GIS, etc.
Apollo Mission to moon -- 1969 • Astronauts took photos of the earth’s land surface from space for the first time • Inspired the development of the first land remote sensing satellite – ERTS (Landsat 1) • William Pecora (USGS Director in 1965) proposes idea of a satellite system to map and monitor the natural resources of earth – new concept • All previous RS satellites were weather related
Landsat – political wrangling • William Pecora (USGS Director in 1965) proposes idea of a satellite system to map and monitor the natural resources of earth – new concept • All previous RS satellites were weather related • Strong political opposition – airborne imagery good enough and more cost effective, etc., etc. • DoD fears compromising its secret operations • Finally approved in 1970 after some tricky political maneuvering (DOI threatens to launch its own satellite system which inspires NASA to come up with a plan)
Earth Resources Technology Satellite (ERTS) – 1972 - 78 • Later (1975) renamed Landsat 1 – the beginning of land remote sensing • Carried two instruments • Return Beam Videocon (RBV) – operational • Multispectral Scanner (MSS) – experimental • RBV failed soon after launch • Scientists began working with MSS data and discovered that the images were extremely useful • First multispectral image of whole earth’s surface (at 80 m spatial resolution)
The Landsat Program • Series of Landsat satellites (1 – 8) have been orbiting earth and collecting imagery since 1972 with one short gap, and are still operating... • Landsat 2 – (1975 – 82) • Carried MSS instrument • Landsat 3 – (1978 – 83) • Carried MSS • 1979 – Success of Landsat mission recognized and program declared operational (vs. experimental) • Control shifted from NASA to NOAA
Landsat (cont.) • Landsat 4 (1982 – 2001) • Carries MSS + new instrument, the Thematic Mapper (TM) • TM has more spectral bands than MSS + a thermal band • Launched by NASA, operated by NOAA but then operations shift to private company called EOSAT in 1984 • In 1998 operation contract transferred to USGS but EOSAT continued to operate satellite and sell the data • TM data were very expensive ($5000/scene). Stifled RS applications • Licensing restrictions were severe under EOSAT. • Land Remote Sensing Policy Act (1992) called for govt. operated Landsat 7. • In 2001 operations returned to U.S. govt. and licenses restrictions lifted.
Landsat (cont.) • Landsat 5 (1984 – 2013) • Carried MSS (but turned off in 1995) • Carried TM • Turned off from Nov 2005 to Jan 2006 due to battery charging issues with solar array • Problem solved by engineers and satellite reactivated • Oct 2007 imaging suspended due to battery problems • Stopped working late in 2011, decommissioned in June 2013.
Landsat (cont.) • Landsat 6 – (1993) • Launched by EOSAT but failed to achieve orbit • Carried a new instrument: Enhanced Thematic Mapper (ETM) • Landsat 5 was still functioning which prevented a “data gap”
Landsat (cont.) • Landsat 7 (1999 – present???) • Carried Enhanced Thematic Mapper Plus (ETM+) • May 2003 failure of scan line correction results in very limited useable imagery • Landsat 5 again becomes important imagery source
Demise of Landsat 5 • In November 2011, Landsat 5 stopped acquiring images after 27 years of service. • Was originally designed to last for 3 years. “This anticipated decline of Landsat 5 provides confirmation of the importance of the timely launch of the next Landsat mission and the need for an operational and reliable National Land Imaging System,” stated Anne Castle, Assistant Secretary for Water and Science at the U.S. Department of the Interior.”
Landsat Data Continuity Mission (LDCM) • Memorandum signed in 2005 called on NASA to develop a Landsat replacement satellite • L8 launched on February 11, 2013 • Significant data gap for the first time in over 30 years of earth observation between demise of Landsat 5 and launch of Landsat 8 • Possible “gap fillers” include India IRS program, French SPOT program, China-Brazil CBERS satellite, others
Advanced Very High Resolution Radiometer (AVHRR) • AVHRR launched in 1978 • Part of then active TIROS series of satellites • Global imagery with a 1 day return time • Used extensively for studying global vegetation and the earth system.
In the meantime…active remote sensing being deployed • 1973: First active microwave sensor (Radar) flown on NASA Skylab • 1978: Seasat launched (Radar) for ocean studies including winds, sea surface topography, wave studies, etc. • 1981: First Shuttle Imaging Radar (SIR-A) flown on space shuttle. Used for land topography • 1991: European Space Agency ERS-1 (radar) put into orbit • 1995: ERS-2
Non-radar image of Sahara desert (sand) showing path to be examined with radar Radar swath showing subsurface channels
Other countries also active • 1986: France. First SPOT multispectral satellite launched. SPOT program still active • 1988: India. IRS-1A launched. First in ongoing IRS series of satellites • 1990: Japan. JERS-1 and 2. • 1991: USSR/Russia. Resurs-O satellite launched. Like Landsat. • 1992: Ukraine (former Soviet state). OKEAN series with multispectral, radar, thermal begun. • 1999: China/Brazil. CBERS satellites (like Landsat). • Others: England, Turkey, Nigeria, Thailand, etc.
SPOT 1 • In Operational Conditions (turned-off in Feb 02) • Operates in Direct Transmission Mode • SPOT 2 • Full Commercial Service • Operates in Direct Transmission Mode • SPOT 3 • Ceased Operation due to Gyroscope Failure in November 1996 • SPOT 4 • Launched in 1998 • Full Commercial Service • SPOT 5 • Launched in May 2002
INIDAN REMOTE SENSING SATELLITE PROGRAM IRS Program • 6 Satellites in orbit • World’s largest Commercial Imagery Provider • IRS-1C, P2, P3, 1D, P4, RESOURCESAT-1 • Carosat-1, RESOURCESAT-2 – launch within next two years. • Partnered with Space Imaging since 1994.
Recent U.S. land observing satellites • 1999: Aqua and Terra platforms • MODIS – Medium/Course resolution multispectral • ASTER – High resolution multispectral • Many other specialized instruments • 2000: Earth Observing Satellite 1 (EO-1) • Hyperion – hyperspectral instrument • ALI - multispectral
Recent remote sensing in the realm of private companies • Digital Globe • Worldview satellite • Space Imaging (now Orbimage) • IKONOS satellite • Google • Google Earth – interface for viewing global RS imagery • Microsoft • Terraserver – free online image depository • Etc.
The Future?? • Increasingly high spatial and spectral resolution imagery • Increased use of active (radar and lidar) remote sensing • Combination of active remote sensing with spectral analysis (e.g., “Flidar”) • Increased use of RS for land management, business and individual activities • And currently unforeseen advances…