Donald Savage
Headquarters, Washington, D.C.                                                 
February 25, 1994
(Phone:  202/358-1547)

RELEASE:  94-30

WIND AND POLAR LAUNCHES TO SLIP FOLLOWING TECHNICAL REVIEW

     The U.S. component of the Global Geospace Science (GGS) 
program, the Wind and Polar spacecraft, will experience launch 
delays of several months to give NASA an opportunity to examine 
the materials and process used to build two power subsystem 
electronic boxes on each spacecraft which are similar in design to 
those  determined to be the cause of the NOAA-13 spacecraft 
failure last year.

     The decision was reached by NASA after a GGS technical review 
last week at NASA's Goddard Space Flight Center (GSFC), Greenbelt, 
Md., where the projects are managed.

     NASA and the spacecraft contractor, Martin Marietta 
Astro-Space, are using this hiatus in part to apply a corrective 
action plan based on lessons learned from both the NOAA-13 and the 
Mars Observer failure review board reports.  Martin Marietta 
Astro-Space, who built both spacecraft which failed last year, 
conducted a special investigation into the failures and conducted 
an intensive internal review of technical concerns with the GGS 
spacecraft.  

     In addition, NASA has conducted several reviews which led to 
the identification of the issues which NASA has decided must be 
resolved before launch, including the power subsystem box.

     Besides the power subsystem boxes, another issue involved 
parts in the command and data handling system which may have been 
subjected to over-stress due to calibration problems with the 
welding machine used to mount electrical  components to circuit 
boards.  Although a sampling of these components was originally 
planned to determine flight compatibility, all of these suspect 
components now will be changed out.

     Wind and Polar, scheduled for April and June 1994 launches, 
respectively, will likely slip into the next fiscal year, but the 
exact dates will not be established until a comprehensive replan 
of the program is complete.

     Wind and Polar will be the U.S. contribution to the 
International Solar-Terrestrial Physics program involving several 
spacecraft in a study of the interaction of the solar wind and 
Earth's magnetic field.
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