cooling water and lithium hydroxide are 
used up by the shuttle backpack during 
each hour of operation in space. Since 
these expended materials must be resup- 
plied from the earth, many thousands of 
pounds would be required to support 
large construction crews working in 
space. To resupply the cooling water 
and lithium hydroxide required for ex- 
pendable systems is too expensive; 
therefore, cooling and carbon dioxide 
control systems that can be regenerated 
for reuse must be developed. 
The spacesuit for this “blue collar” 
EVA system must be durable and reli- 
able enough for months of daily use with 
only routine maintenance. It must also 
operate with an internal pressure higher 
than one-fourth of an atmosphere — on 
the order of one-half of an atmosphere 
or more. This is needed to avoid the 
potential danger of decompression sick- 
ness, or “the bends,” when the astro- 
nauts decompress from the pressure of 
one atmosphere in the shuttle or space 
station cabin to the lower suit pressure. 
This is exactly the same bends problem 
that deep-sea divers may encounter 
when ascending after a dive. In both 
cases, the problem occurs when the am- 
bient pressure around the body is re- 
duced after a period in which the body’s 
tissues and fluids have become satu- 
rated with nitrogen and the body is in 
equilibrium with its surroundings. The 
pressure reduction takes place at the 
end of an extended deep dive and re- 
quires decompression stops on the way 
to the surface. It occurs at the beginning 
of an EVA. The bends are avoided when 
using the shuttle suit by having the 
astronaut breathe pure oxygen for three 
hours prior to an EVA. This period of 
wasted time would be intolerable for 
routine EVA operations. 
As already mentioned, the suit, which 
now comes in separate pieces, can be 
assembled according to the require- 
ments of a particular mission. The basic 
torso with integral, regenerative life-sup- 
port systems could have lightweight fab- 
ric arms and legs attached when it is to 
be used in low Earth orbit and arms and 
legs with additional shielding as protec- 
tion from radiation when used at higher 
altitudes. This shielding could easily be 
provided by making the suit extremities 
and the torso out of the same material, 
probably a metal such as aluminum. 
Many future space missions have 
been suggested. Before they become re- 
ality, however, new portable life-support 
systems must be developed. □ 
