Ed Campion
Headquarters, Washington, D.C.                       February 
17, 1993
(Phone:  202/358-1778)

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

RELEASE:  93-31

SPACEWALK  ADDED TO APRIL SPACE SHUTTLE FLIGHT

     A spacewalk has been added to Space Shuttle mission STS-57 
aboard Endeavour, set for an April launch, as part of a series 
of spacewalk tests NASA will conduct during the next three years 
to prepare for the construction and maintenance of Space Station 
Freedom.

    The main objectives of the STS-57 mission are to retrieve 
the European Retrievable Carrier (EURECA) deployed during a 
Shuttle flight in August 1992 and to conduct research in the 
Spacehab module which more than doubles the amount of middeck 
research locker space aboard the orbiter.

     In addition to accomplishing the general objectives of the 
spacewalk test series, the STS-57 extravehicular activity (EVA) 
will allow some of the spacewalking procedures, using the 
Shuttle's mechanical arm, planned for use in servicing the 
Hubble Space Telescope (HST), to be tested.  Those procedures 
involve work by astronauts on a platform at the end of the 
Shuttle's arm.  The arm will be aboard Endeavour for grappling 
the EURECA satellite.

     "The EVA will benefit us in two ways: first, we'll gather 
generic data on human performance capabilities and limitations 
in space and secondly, we'll perform some tasks similiar to 
those required for the HST mission later this year," said Ron 
Farris, Chief of the Extravehicular Section at the Johnson Space 
Center." 


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    "We'll also demonstrate that the EVA community can plan, 
train and fly four missions this year and in that sense, it will 
be a banner year for EVA and will be somewhat representative of 
the EVA efforts required to build and maintain Space Station 
Freedom," Farris added.

     The spacewalk tests, as performed during STS-54 in January, 
concentrate on defining the limits of spacewalking abilities, 
better understanding 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.  The tests also expand 
the spacewalk experience levels among the astronaut corps, 
Shuttle flight controllers and spacewalk training instructors.

     The specific tasks to be performed on STS-57 are still 
being evaluated by flight planners, however they will 
concentrate on these goals and be similiar to the STS-54 tasks  
although they will feature use of the robot arm. The STS-57 
spacewalk, as with the STS-54 spacewalk and other such spacewalk 
tests will be done without any impact on the mission's main 
objectives and will carry a low priority among the mission's 
tasks.
 
     STS-57 crew members G. David Low and Jeff Wisoff will 
perform the EVAs.

     With the spacewalk performed in January, those planned for 
April and July and the spacewalks planned for the STS-61 HST 
servicing mission in December, a total of four Shuttle flights 
this year feature spacewalks. 

   Four Shuttle missions with planned spacewalks in one year 
ties a NASA record for missions with EVAs set when four 
spacewalk missions were flown in 1984.


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