Exploring the Unknown - NASA's History Office

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OBSERVING THE EARTH FROM SPACE
POES also will have operational satellites.(7) Over most of this period, both programs
would be flying duplicate instruments. The nation would be more efficiently served if
NASA would develop and fly the prototypes once and then transfer the systems to NOAA’s
operational program for future flights.
Convergence studies began in 1972 and have continued ever since.(8) NOAA recently
performed an internal study of the opportunities available through convergence of the programs.(9)
Recently, initial talks have begun among the three agencies with the goal of performing
another study of convergence opportunities among the three programs.(10) What
is needed, however, is a clear decision to create a single, civilian polar satellite program.
Currently, the NOAA POES program, the DOD DMSP program, and the NASA EOS-
PM program all are in various stages of developing new spacecraft and instruments. In the
next 10 years, the estimated total cost for these three efforts exceeds $6 billion in development,
production, and operations costs. However, many policy makers feel that the
nation cannot afford to develop three separate satellite systems with such similar missions.
For example, Congressman George Brown of California has stated that a converged
system seems more achievable than in the past. He therefore has directed NOAA to work
with DOD and NASA to “jointly study and assess the possible benefits and mechanisms for
merging all or parts of the three programs.”(11) Senator James Exon of Nebraska was
more direct in his letters to DOD and Commerce: “The nation cannot afford to maintain
and modernize two satellite weather constellations.”(12) Recently, at the National Space
Outlook Conference, Air Force General Charles Horner, Commander United States
Space Command, stated: “How you do convergence is really the question, not if you do
convergence.”(13)
A single operational polar satellite program could meet the needs of all users by incorporating
key DOD requirements into the NOAA POES program. Furthermore, the synergy
achieved through DOD and NOAA cooperation could allow both agencies to meet
critical operational requirements (such as collecting oceanographic and global tropospheric
wind data) which neither agency has been able to afford alone. The converged
operational program could save additional costs by using the NASA EOS program’s stateof-the-art
spacecraft and instruments instead of forcing NOAA to design and build its own.
The result would be a single development program (compared to the three planned
today) and minimal overlap between NASA’s climate research and the NOAA-DOD converged
operational meteorological missions.
The difficulty will be to successfully incorporate DOD requirements into the program.
Based upon historical studies, key areas requiring consideration are data deniability, orbit
selection, international cooperation, and adequate oversight to ensure DOD concerns are
adequately met.(14) The following summarizes how each of these can be addressed:
Data deniability. The satellite must broadcast data free to everyone but also have the
capability to deny data to specific adversaries. New technology, such as that used to deny
cable-TV pay channels to non-subscribers, makes this task easier.
Orbit selection. Currently, the DOD desires the capability to change its satellite orbits
depending on mission requirements. Past studies have identified a three-satellite constellation
as sufficient for meeting all orbit needs.(15) Allowing DOD to influence orbits
selection should alleviate their concerns.
International cooperation. A NOAA-led system could easily maintain and even
improve international cooperation in environmental data exchange. However, since
NOAA plans to use foreign satellites as part of the converged program, DOD may be reluctant
to rely upon foreign satellites for important data. This concern could be alleviated by
maintaining one or more ground spare U.S. satellites at all times that could be launched
if a foreign-controlled satellite ever became unreliable.