Ed Campion
Headquarters, Washington, D.C.                                             
February 3, 1993
(Phone:  202/453-8536)

James Hartsfield
Johnson Space Center, Houston
(Phone:  713/483-5111)


RELEASE:  93-21

SPACEWALK ADDED TO JULY SPACE SHUTTLE FLIGHT

   A spacewalk has been added to Space Shuttle mission STS-51 
aboard Discovery, set for a July launch, to continue 
extravehicular activity tests begun with the addition of a 
spacewalk to NASA's first 1993 Shuttle flight in January.

   The STS-51 spacewalk is part of a series of tests NASA will 
conduct during the next 3 years to prepare for the construction 
and maintenance of Space Station Freedom, scheduled to be built 
in orbit starting in early 1996.

   "The addition of the spacewalk to STS-51 will allow us to 
continue refining our knowledge of human performance 
capabilities and limitations during spacewalks", said Ron 
Farris, Chief of the Extravehicular (EVA) Section at the Johnson 
Space Center, Houston. 

   "This EVA constitutes a continuing committment by NASA to 
advance our preparation for future EVA missions such as the 
Hubble Space Telescope servicing and Space Station Freedom 
assembly flights," Ferris added.  Other 1993 Shuttle flights 
remain under consideration for the addition of spacewalks as 
well.

   The tests, as performed during STS-54 in January, concentrate 
on defining the limits of spacewalking abilities, better 
understanding of the differences between true weightlessness and 
the ground training facilities that simulate weightlessness and 
gaining more insight into the times required for various tasks 
to be performed while spacewalking.  They also expand the 
experience levels among the astronaut corps, Shuttle flight 
controllers and spacewalk training instructors.

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   The specific tasks to be performed on STS-51 are still being 
evaluated by flight planners, however, the tasks will 
concentrate on these goals and be similiar to the tasks done 
during STS-54.  The STS-51 spacewalk, as with the STS-54 
spacewalk and future tests, will be done without any impact on 
the main objectives of the mission and will carry a low priority 
among the mission's tasks. STS-51's primary objective will be to 
deploy the Advanced Communications Technology Satellite.  STS-51 
crew members Jim Newman and Carl Walz will perform the 
spacewalk.

   With the spacewalk performed in January and the one planned 
for July, a total of three Shuttle flights this year include 
spacewalks as now planned.  Shuttle mission STS-61, scheduled 
aboard Endeavour in December to service several instruments and 
equipment on the orbiting Hubble Space Telescope, will feature 
several spacewalks.  However, the STS-61 spacewalks are not part 
of the test series.

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