6.0 PLANNED EARTH RESOURCES SATELLITES
Within the past several years several commercial ventures
have been proposed in the United States. Lockheed has
proposed the development of a commercial satellite
system that will provide 1 meter spatial resolution data.
CTA has proposed the initial flight of a 3 meter spatial
resolution system and eventually a 1 meter spatial
resolution system.
6.1 LANDSATS -6, -7 and -8.
Landsat-6 was launched on October 5, 1993 and although
the Enhanced Thematic Mapper (ETM) operated to
specifications, the spacecraft failed to achieve orbit when
the orbit kick motor inadvertently drove the spacecraft bus
back into the atmosphere and ultimately the Indian Ocean.
For the first time in the history of the Landsat program no
backup spacecraft was funded by the government and this
shortsighted economy, plus a complex management
scheme, has resulted in a serious setback for the U. S.
Landsat program. The ETM on Landsat-6 was to provide
the Landsat TM bands used on Landsats -4 and -5, and
also a panchromatic sharpening band that would have
provided 15 meter spatial resolution data.
The U. S. Government has made a committment to fly
Landsat-7 in 1997 with an Enhanced Thematic Mapper-
Plus (ETM+) sensor. This plan deletes the planned High
Resolution Multispectral Stereo Imager (HRMSI) under
development by Hughes Santa Barbara Research Center.
That sensor would have provided along track synoptic
multispectral stereoscopic imagery with 5 meter spatial
resolution. The ETM+ will have the same bands as the
Landsat-6 ETM, but will also have a thermal band with 60
meter spatial resolution.
There is no formal commitment to the Landsat program
beyond Landsat-7, however the U. S. Government is
supporting studies of government requirements for land
satellite data beyond Landsat-7, Landsat-7 follow on must
provide continuity with Landsat TM data, but will
demonstrate new technology. NASA currently plans to
drop the thermal band beginning with the Landsat-7 follow-
on experiment. Landsat-7 follow-on will be a NASA "New
Millenium" mission that will be a proof of concept for new
solid state imaging technologies. Currently NASA is
considering providing Landsat ETM-Plus bands, some
atmospheric correction bands and a wedge imaging
spectrometer for flight in 1999.
Landsat-8 would fly in 2004, on EOS-AM2 in this scenario.
‘6.2 SPOT-4, 5 and 6.
SPOT-4 will be launched in 1997 and it will have improved
data storage capabilites and a 1.6 micrometer band.
SPOT-5 is planned for a launch at the turn of the century
and it will have a panchromatic sensor with fore and aft
stereoscopic viewing and 5 meter spatial resolution. The
multispectral focal plane on SPOT-5 will provide 10 meter
spatial resolution data. A mid-infrared focal plane may also
be included on SPOT-5 and it may collect thermal data in
the 10.2 to 12.5 micrometer band. SPOT-6 could be
launched in the 2003 to 2010 time frame. These plans are
testimony to the commitment the French Government has
placed on the SPOT program.
6.3 Japan Advanced Land Observing Satellites
ASTER. The next Japanese earth observations mission will
occur on EOS-1 platform in 1998. NASA will provide
launch and on orbit services for the Advanced Spaceborne
Thermal Emission and Reflection Radiometer (ASTER), a
three sensor instrument that will provide synoptic
stereoscopic data at 15 meter spatial resolution in 3 bands,
30 meter shortwave infrared data in six spectral bands and
multiband thermal data in five spectral bands with 90 meter
spatial resolution
AVNIR-2. The Japanese are developing an Advanced
Visible and Near Infrared Radiometer-2 for launch after
2000. This instrument will have 10 meter spatial resolution,
across a 70km swath, in four multispectral bands similar to
those on the Thematic Mapper. The multispectral sensor
will be pointable across track. It will also have a
panchromatic sensor which will provide 2.5m spatial
resolution in across a 35km swath and will provide a base
to height ratio of 1.
6.4 Lewis and Clark Satellites
Clark. Recently NASA selected CTA of McLean, Va to
build a low-cost satellite ($49 million) to be launched later
in 1996 and would provide the user community with high-
spatial resolution data. Known as Clark (after the explorers
Lewis and Clark), it will carry a 3-meter resolution sensor
operating in panchromatic mode with a 6 km swath width
and a 15 meter spatial resolution sensor operating in the
VNIR with a 30 km swath width. A second satellite of This
type is planned for launch later in the decade, with a 1
meter spatial resolution panchromatic sensor.
Lewis. Under the same program, NASA also selected
TRW to build and launch the first spaceborne hyperspectral
imaging sensor. The spacecraft is known as Lewis and its
sensor is the Hyperspectral Imager (HSI). The HSI will
acquire contiguous spectral data from 400nm to 2500nm
in 384 spectral bands, which will be resampled to 175
spectral bands to improve the signal-to-noise ratio. The
sensor will have an innovative design, weighing only 21 kg.
Spatial resolution for this sensor will be 30 meters and it
will be sharpened by a 5 meter panchromatic sensor. The
swath width would be less than 15 km.
6.5 EarlyBird and QuickBird
EarthWatch (formed by the merging of Worldview Corp and
Ball Aerospace in 1995) is building two small lightweight
satellites. The first is called EarlyBird and will be launched
in 1996 with two sensors: one operating in panchromatic
mode (450nm to 800nm) with 3 meter spatial resolution
and the other in multispectral mode (3 bands in the 500-
590nm, 610 to 680nm and 790 to 890nm ranges) with 15
meter spatial resolution. Data from both sensors will be
conbined into a single dataset with improved spatial and
spectral resolution. The satellite will orbit at 470km, will
have 30-degree fore-and-aft and side-to-side pointing
capability for stereoscopy. Swath width will be 6 km in
panchromatic mode and 30 km in multispectral mode.
The second satellite is called QuickBird and is planned for
launch in 1998, with improved spatial and spectral
resolution. The panchromatic sensor will cover a spectral
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
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