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Mercury spacecraft cooling question



 
 
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  #1  
Old July 8th 08, 10:57 PM posted to sci.space.history
Pat Flannery
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Default Mercury spacecraft cooling question

I was looking at some cutaways of spacecraft, and am trying to figure
something out.
Both Gemini and Apollo incorporated significant cooling radiators in the
designs (external on the Apollo SM, mounted inside the skinning of the
Gemini equipment module), but how was cooling handled on Mercury? There
aren't any radiators on its exterior, and although you could use water
boil-off for cooling on fairly short flights, the 34 hour long Faith 7
flight would seem to need a lot of water to make this concept work for
that period of time.

Pat
  #2  
Old July 8th 08, 11:37 PM posted to sci.space.history
Alan Erskine[_2_]
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Default Mercury spacecraft cooling question

"Pat Flannery" wrote in message
...
I was looking at some cutaways of spacecraft, and am trying to figure
something out.
Both Gemini and Apollo incorporated significant cooling radiators in the
designs (external on the Apollo SM, mounted inside the skinning of the
Gemini equipment module), but how was cooling handled on Mercury? There
aren't any radiators on its exterior, and although you could use water
boil-off for cooling on fairly short flights, the 34 hour long Faith 7
flight would seem to need a lot of water to make this concept work for
that period of time.

Pat


Several things to consider:

1 Mercury was battery-powered, while Gemini and Apollo used fuel cells -
much more heat generated.
2 Mercury was only one-man; less people = less heat generated.
3 Mercury was a _very_ basic vehicle; while Gemini was somewhat more
complicated and Apollo was a whole different story where complexity is
concerned.
4 In Mercury, the crew member only had to sit fairly still; in Gemini,
there was a lot more activity (EVA included).

On Gemini, were the radiators also for the crew and electrical systems?


  #3  
Old July 8th 08, 11:46 PM posted to sci.space.history
Rick Jones
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Posts: 685
Default Mercury spacecraft cooling question

Pat Flannery wrote:
I was looking at some cutaways of spacecraft, and am trying to figure
something out.
Both Gemini and Apollo incorporated significant cooling radiators in
the designs (external on the Apollo SM, mounted inside the skinning
of the Gemini equipment module), but how was cooling handled on
Mercury? There aren't any radiators on its exterior, and although
you could use water boil-off for cooling on fairly short flights,
the 34 hour long Faith 7 flight would seem to need a lot of water to
make this concept work for that period of time.


The first hit I got on a web search for "Mercury Capsule Cooling" was:

http://ntrs.nasa.gov/search.jsp?R=14153&id=8&qs=Ns%3DHarvestDate%257C0% 26N%3D4294967096%26Ne%3D25

For which the abstract reads:

The approach to orbital thermal control of the Project Mercury
capsule environment is relatively unsophisticated compared with
that for many unmanned satellites. This is made possible by the
relatively short orbital flight of about 4 1 2 hours and by the
presence of the astronaut who is able to monitor the capsule
systems and compensate for undesirable thermal conditions. The
general external features of the Mercury configuration as it
appears in the orbital phase of flight are shown. The conical
afterbody is a double-wall structure. The inner wall serves as a
pressure vessel for the manned compartment, and the outer wall, of
shingle type construction, acts as a radiating shield during
reentry. Surface treatment of the shingles calls for a stably
oxidized surface to minimize reentry temperatures. The shingles
are supported by insulated stringers attached to the inner
skin. Areas between stringers are insulated by blankets of
Thermoflex insulation. This insulation is especially effective at
high altitude due to the reduction of its thermal conductivity
with decreasing pressure. As a result of the design of the
afterbody for the severe reentry conditions, the heat balance on
the manned compartment indicates the necessity for moderate
internal cooling to compensate for the heat generation due to
human and electrical sources. This cooling is achieved by the
controlled vaporization of water in the cabin and astronaut-suit
heat exchangers.

Not sure if there is an online copy, you may have to order paper. I
notice they mention 4 1/2 hours vs the 34 of that other flight. Might
have to get the paper to resolve that one. Maybe they just left the
rest of the capsule (un)insulated "just enough?"

rick jones
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  #4  
Old July 9th 08, 12:28 AM posted to sci.space.history
Alan Erskine[_2_]
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Default Mercury spacecraft cooling question

"Rick Jones" wrote in message
...

The first hit I got on a web search for "Mercury Capsule Cooling" was:

http://ntrs.nasa.gov/search.jsp?R=14153&id=8&qs=Ns%3DHarvestDate%257C0% 26N%3D4294967096%26Ne%3D25


Still looking; try this for starters:
http://www.hq.nasa.gov/office/pao/History/SP-6/ch1.htm


  #5  
Old July 9th 08, 12:44 AM posted to sci.space.history
Rick Jones
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Posts: 685
Default Mercury spacecraft cooling question

It is drifting, but while perusing some of the hits I got, I came
across this one:

http://www.time.com/time/magazine/ar...romoid=googlep

which I thought was somewhat interesting.

rick jones
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web2.0 n, the dot.com reunion tour...
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
  #6  
Old July 9th 08, 01:43 AM posted to sci.space.history
Alan Erskine[_2_]
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Default Mercury spacecraft cooling question

From he http://history.nasa.gov/alsj/apollo.precurs.html

"The Gemini program provided opportunities to prepare for Apollo in other
ways as well. The crews of Gemini 5 and 7 spent eight and fourteen days in
space, respectively and, although they had far less elbow room than the
Apollo crews, they proved beyond any doubt that there were no physiological
or operational barriers to the conduct of a ten-day lunar mission. Five of
the Gemini astronauts ventured outside their spacecraft and, when they tried
to do strenuous work, discovered that the air-cooling system used in the
Gemini suits wasn't going to be adequate for Apollo. An astronaut sitting
inside a cramped capsule simply couldn't work hard enough to generate much
body heat and, consequently, could be kept cool by oxygen flowing through
the suit. But when he got outside and flexed his arms and legs against the
internal pressure of the suit, the extra heat load quickly overwhelmed the
airflow cooling system. What was needed was a system which could carry away
the excess heat; and, as a result of the Gemini experience, NASA and its
contractors developed a system for circulating cooled water through tubes
woven into an undergarment worn next to the astronaut's skin"

http://www.hq.nasa.gov/office/pao/History/SP-45/ch3.htm under "[52] Table
3-II. Summary of Modifications to MA-9 spacecraft." adds "5. Added 9 lb of
cooling water.... Increase cooling capability because of mission [duration]"


  #7  
Old July 9th 08, 02:15 AM posted to sci.space.history
Rick Jones
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Default Mercury spacecraft cooling question

Alan Erskine wrote:
http://www.hq.nasa.gov/office/pao/History/SP-45/ch3.htm under


Nice link, nearly got in trouble with my wife for staying at work
longer to read it

For some reason, perhaps all the talk about weight gain in
contemporary vehicles, I found this one fun:

http://www.hq.nasa.gov/office/pao/Hi...-45/fig3.5.htm

rick jones
--
Process shall set you free from the need for rational thought.
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
  #8  
Old July 9th 08, 02:26 AM posted to sci.space.history
Alan Erskine[_2_]
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Posts: 1,316
Default Mercury spacecraft cooling question

"Rick Jones" wrote in message
...
It is drifting, but while perusing some of the hits I got, I came
across this one:

http://www.time.com/time/magazine/ar...romoid=googlep

which I thought was somewhat interesting.


Pity NASA doesn't read its own reports; it might learn something.


  #9  
Old July 9th 08, 03:28 AM posted to sci.space.history
Pat Flannery
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Posts: 18,465
Default Mercury spacecraft cooling question



Rick Jones wrote:
It is drifting, but while perusing some of the hits I got, I came
across this one:

http://www.time.com/time/magazine/ar...romoid=googlep

which I thought was somewhat interesting.


This one:

"On the Cooper flight, the control cords holding the retrorocket package
to the capsule failed to fall free as intended because the explosive
separating devices 'were not loaded with the appropriate charge.' "

.....is very similar to the equipment module separation problems the
Vostok spacecraft had that would leave the two spacecraft modules
attached by a umbilical till aerodynamic forces during reentry pulled
them apart.

Pat
  #10  
Old July 9th 08, 05:16 AM posted to sci.space.history
Alan Erskine[_2_]
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Posts: 1,316
Default Mercury spacecraft cooling question

"Pat Flannery" wrote in message
...
This one:

"On the Cooper flight, the control cords holding the retrorocket package
to the capsule failed to fall free as intended because the explosive
separating devices 'were not loaded with the appropriate charge.' "

....is very similar to the equipment module separation problems the Vostok
spacecraft had that would leave the two spacecraft modules attached by a
umbilical till aerodynamic forces during reentry pulled them apart.

Pat


With the exception being that with Mercury, the spacecraft didn't go into
the atmosphere nose-first.


 




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