Satellites You Need to Know: Landsat, the Granddaddy of them all

The Landsat program is a set of
moderate resolution satellites that have been collecting images of the Earth for
nearly 39 years, the longest continuous mission of its kind. It has many applications
for natural security topics. Currently it is operating two satellites - Landsat-5, launched
in 1984, and Landsat-7
launched in 1999 – although their continued operation remains in doubt. As a 2007
report
by the Office of Science and Technology Policy concluded, “The currently
functioning U.S. moderate resolution satellites (Landsat 5 and 7) are operating
beyond their design lifetimes in degraded status and are subject to failure at
any time.” To maintain the uninterrupted flow of moderate resolution data, the
United States must ensure that the successor program, Landsat Data Continuity
Mission (LDCM), gets up and running quickly.

History

Influenced by the Apollo mission,
the director of U.S.
Geographical Survey first proposed the idea of a remote sensing project, which
became Landsat in 1965. After overcoming intense opposition from some within
government, Landsat-1 was launched on July 23, 1972. At the time it was the first Earth observation
satellite in orbit with the explicit purpose of studying and monitoring the
planet. Originally only planned for a one year mission, the satellite operated until January 1978,
providing approximately 300,000 images of the Earth. Although originally only conceived of as a
five satellite program, six satellites in addition to Landsat-1 have been
designed, however Landsat-6
failed during the launch and, consequently, never reached orbit.

Maintaining congressional support
has remained a challenge throughout Landsat’s history. Soon after the launch of
Landsat-5, Congress passed the Land
Remote-Sensing Commercialization Act of 1984, which privatized the program.
Under the instruction of this legislation, the National Oceanic and Atmospheric
Administration, which had responsibility for the Landsat program, sold the
rights to Landsat data to Earth Observation Satellite Company (EOSAT), a
private company.
The program faltered under privatization however, because there were not enough
consumers of the data to provide continuous imaging. By 1989, NOAA instructed the EOSAT
to turn the satellites off for good. The program was returned to government
control under the first Bush administration when Congress passed the Land Remote Sensing Policy
Act of 1992, repealing the 1984 law and ordering the construction of the Landsat-7
satellite.

Uses
and Users

Landsat data has myriad uses,
including ones related to some aspect of natural security. Among its
environmental benefits, Landsat data have been used to monitor
deforestation and various aspects of
climate change including: glacier
monitoring, carbon
stocks and the impact that climate
change is having on Africa. Data have also been used to
assess the impact of natural disasters, including the
recent tsunami in Japan, as well as monitor other environmental trends, such as droughts
and volcanic
activity. Landsat data have also been used to improve agricultural
productivity in various ways, including monitoring crop
harvests, estimating production
levels, measuring crop water
demand and even combating crop
insurance fraud. Other practical uses include fighting
hunger and poverty and monitoring the implications of
urban growth.      

Similarly, Landsat is
used by many stakeholders, representing a diverse group of government
agencies and people outside of government, especially those in academia. The
program is jointly administered by NASA
and the U.S. Geological Survey (USGS),
but data are distributed throughout the government, including to  military officials and international
government organizations. The data are used by these groups to facilitate
decision-making. In addition, people outside of government have used Landsat
data extensively. By one
measurement, for instance, over 3,200 peer-review articles have used
Landsat data to evaluate scientific research, according to the records of the Science Citation Index.  

The
Future of Landsat

Reflecting upon the impact
Landsat has had, Dr. Darrel Williams, the Landsat 7 Project
Scientist said, “It was the granddaddy of them all, as far as starting the
trend of repetitive, calibrated observations of the Earth at a spatial
resolution where one can detect man’s interaction with the environment.” With
so much utility derived from Landsat data, the government has taken a number of
steps to ensure the continuation of moderate resolution satellites.

In December 2005, the Office of Science
and Technology Policy issued a memorandum ordering that NASA build a new
moderate resolution satellite to be operated by USGS. This satellite became the
LDCM, which is
planned for a five year mission but will maintain enough fuel for up to ten
years of operation. It is currently
scheduled to be launched in December 2012.  

In addition, the OSTP memorandum set up an
interagency working group to determine the future path of land imaging. This group
met on a weekly basis between January and December of 2006 and issued
its finding in a report that was released in August 2007. This report laid
out a plan for implementing the goal of the 2005 memorandum which pledged “to
transition the Landsat program from a series of independently planned missions
to a sustained operational program.” As
we previously noted, the president’s new budget requests adequate funding
for bringing this plan to fruition. Thus for now the future of Landsat is
secure, yet in an era of sweeping budget cuts, this could change. We’ll let you
know if it does.