491 
(CCSDS), and others, in order to take advantage 
of the work of these organizations. 
EOSDIS will be a major component of the overall 
U.S. interagency approach to data management as 
part of the U.S. Global Change Research Program. 
The Interagency Working Group on Data Management 
for Global Change (IWGDMGC), which reports as an 
ad-hoc group to the White House OSTP/Committee 
on Earth Sciences (CES), is currently developing 
an implementation approach for a U.S. Global 
Change Data and Information System (GCDIS) which 
will link the federal agency data systems, in 
cluding EOSDIS, into an interoperating system, 
with common interfaces, practices, and standards 
where these can be shown to be beneficial in 
facilitating user access to the agencies' data 
holdings. Interagency agreements between NASA 
and USGS, and between NASA and NOAA, have been 
developed to begin as early as possible in 
designing common agency approaches to management 
of data in the EOS era. Agreements are cur 
rently being developed with other organizations 
and international partners to ensure wide par 
ticipation in EOSDIS implementation and to 
encourage open data exchange policies. 
6 EARLY-EOSDIS PROGRAM 
The Early-EOSDIS program, beginning in 1990 and 
continuing until the first EOS platform launch, 
will encompass the production of pathfinder data 
sets, establishment of initial system elements 
which will provide substantially improved ser 
vices to users, and integration of metadata, 
communications, standards, and other features. 
This will be accomplished in four phases leading 
up to the fully operational capability at 
launch. A preliminary outline of these phases 
is given below. Further details will be 
provided in a Program Plan currently under 
development by NASA Headquarters. 
Phase 1 - from early 1990 through Phase C/D con 
tract award in mid-1992. During this period ser 
vices to users of existing NASA systems (e.g. 
NODS, NCDS, PLDS, SDCS) will be augmented, and 
new IMS and DAAC functions added. Initial in 
frastructure such as connecting networks and 
standards for software, documentation, and data 
formats will be implemented. Pathfinder data 
sets will be generated and archived, and devel 
opment plans for the DAACs will be established 
through agreements with the institutions in 
volved. 
Phase 2 - from the end of Phase 1 to initial 
EOSDIS functionality in early 1994. During this 
period initial deliveries by the Phase C/D con 
tractor will occur. New capabilities will be 
placed in service as they gain acceptance by the 
EOSDIS project, the DAACs, and participating 
scientists. This phase will culminate in the 
availablity of working capabilities (albeit at 
less than full capacity) for all EOSDIS data 
production, archiving, and distribution func 
tions . 
Phase 3 - from the end of Phase 2 to full func 
tionality for the DAACs, IMS, and SCFs in early 
1995. During this period EOS investigators will 
be working on algorithms, algorithm software 
will be migrating to the DAACs for implementa 
tion, and integration and testing of the soft 
ware will occur. 
Phase 4 - from the end of Phase 3 to full EOSDIS 
functionality and capacity at EOS-A launch in 
1997. During this phase, final deliveries of 
all EOSDIS elements will be completed, integra 
tion and testing of all functions, including 
command and control, will occur, and system 
readiness tests will be completed. 
During all four phases the major emphasis will 
be on improving scientific productivity through 
the assurance of timely, reliable, and facile 
access to data. 
ACKNOWLEGEMENTS 
The authors wish to acknowlege the contributions 
of all EOS science investigators, project, and 
program personnel in developing the EOSDIS con 
ceptual framework. The contents of this paper 
draw significantly on work performed by EOSDIS 
project and contractor personnel during the 
EOSDIS Phase A and B study phases. The EOSDIS 
Program at NASA Headquarters is under the direc 
tion of Dr. Dixon M. Butler. 
REFERENCES 
NASA, 1988a. NASA Earth Science and Applica 
tions Division: The Program and Plans for FY 
1988-1989-1990. National Aeronautics and Space 
Administration, Code SE, Washington, DC 20546. 
NASA, 1988b. Earth System Science - A Program 
for Global Change: A Closer View. Report of the 
Earth System Sciences Committee, NASA Advisory 
Council, National Aeronautics and Space Admin 
istration, Washington, DC 20546.