Apollo spacecraft shielding material

Hi...
I'm doing a research project for school on the apollo missions and I have
been having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts. I've found
some radiation statistics I'm curious how they solved this problem. also it
is kinda needed for my project.Can anyone help? Thanks,
Jimmy

In article ,
res17uuf wrote:
...having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts.

Apollo couldn't spare any mass for actual shielding. The Command Module
heatshield and the equipment covering its walls provided a fair bit of
natural shielding, as did the Service Module attached behind it, and that
was deemed sufficient. This was ultimately confirmed by radiation
instruments carried on some of the unmanned Apollo tests.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

"res17uuf" wrote in message . ..
Hi...
I'm doing a research project for school on the apollo missions and I have
been having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts.

There was no purpose-built radiation shielding on the Apollo capsules.
However, the capsule's heat shield (always at least 0.75-inches thick,
IIRC) and other equipment/structures were deliberately used to provide
radiation shielding, even though they had other, primary purposes.

The capsule had an average of 8 grams per centimeter of shielding
(IIRC), especially from the stern, where it had the long, fuel-filled
service module, with the heavy rocket motor at the stern.

Quoting Henry Spencer from many moons ago:

"The Apollo CSM used its heatshield and other equipment -- the crew
were basically in the center of the CSM, with everything else around
them, and essentially no mass had to be added specifically as
shielding. The Apollo 4 and 6 unmanned tests went out through the
belts and then came back in, carrying radiation instruments in the
cabin to confirm this:

("Apollo 4 and 6 Radiation Analysis", White&Hardy, J. Spacecraft 7.7,
July
1970, originally presented at a conference in January 1969.)

These missions show that there will be no biological hazard
associated with passage through the trapped radiation belts
during the translunar and trans-Earth phase of Apollo lunar
missions, providing that there are no further high-altitude
nuclear tests and that astronaut activity is confined to the
command module during belt passage."

I've found some radiation statistics I'm curious how
they solved this problem. also it is kinda needed for my
project.Can anyone help? Thanks, Jimmy

Mike Miller, Materials Engineer

"res17uuf" writes:

I'm doing a research project for school on the apollo missions and I have
been having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts. I've found
some radiation statistics I'm curious how they solved this problem.

They didn't. The Apollo capsules carried no addition "shielding" beyond
their structural mass. They relied on passing through the van Allens quickly
enough that the integrated radiation dose was within "acceptable" limits.


-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'

In article ,
"res17uuf" wrote:

I'm doing a research project for school on the apollo missions and I have
been having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts. I've found
some radiation statistics I'm curious how they solved this problem. also it
is kinda needed for my project.Can anyone help? Thanks,

I'm not an authority, but I believe there was no particular shielding
for passing through the belts. The walls of the spacecraft are like
aluminum foil; I don't think they attenuate the radiation at all. The
strategy for passing through the belts was simply to do so as quickly as
possible, to minimize the accumulated radiation damage.

Best,
- Joe

,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| http://www.macwebdir.com |
`------------------------------------------------------------------'

"res17uuf" wrote in message . ..
Hi...
I'm doing a research project for school on the apollo missions and I have
been having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts. I've found
some radiation statistics I'm curious how they solved this problem. also it
is kinda needed for my project.Can anyone help? Thanks,
Jimmy

To my knowledge, the astronauts stayed in the CM, which was the best
shielded part, and went through the van Allen belts in a short time,
before they could get too much radiation.

Actually IIRC the main worry was not the van Allen belts, but a major
solar flare while they were outside the Earth's magnetic field
protection.

Regards

Carsten Nielsen
Denmark

"res17uuf" wrote in message
...
Hi...
I'm doing a research project for school on the apollo missions and I have
been having trouble finding information on what was used to shield the
apollo vehicles when they passed through the van allen belts. I've found
some radiation statistics I'm curious how they solved this problem. also
it
is kinda needed for my project.Can anyone help? Thanks,
Jimmy

The vehicles passed through the belts very quickly, thus limiting the
exposure to radiation.
--
Alan Erskine
alanterskine(at)hotmail.com

Iraq, America's new Vietnam

"res17uuf" wrote in message
. ..
I'm doing a research project for school on the apollo missions
and I have been having trouble finding information on what was
used to shield the apollo vehicles when they passed through the
van allen belts. I've found some radiation statistics I'm
curious how they solved this problem. also it is kinda needed
for my project.

In "The Space Environment" by N. H. Langton (1969) they say the
Apollo plan was to avoid most of the van Allen belt radiation
by going near the edge. Cape Canaveral is 28.5 degrees North,
which is about right for going toward the Moon. The radiation
belts are inclined about 11 degrees (as is the Earth's magnetic
field) and are about +- 40 degrees wide. If you time your
departure for the Moon so you are at the Northern part of your
orbit while over the place where the radiation belts are South,
you can miss most of the radiation. From pages 134-136 I quote:

The problem of making a suitable exit through the trapped radiation
is not in fact particularly difficult. The lunar missions at
present proposed will leave from a parking orbit below the van Allen
region and the most opportune instant to leave this orbit will of
course be chosen. The radiation intensity is quite low at and above
magnetic latitude 40 degrees North or 40 degrees South and the
geomagnetic dipole is at an angle of 11 degrees to the Earth's
rotational axis. The rotational axis is at an angle of 66.5 degrees
to the plane of the ecliptic at the equinoxes and the plane of the
lunar orbit is inclined at 5 degrees to that of the ecliptic,
around which it rotates with a period of just over 18 years.
Accordingly, once every 18 years, at the equinox, there is an
instant each day when a straight line from Earth to the Moon is the
normal at magnetic latitude 39.5 degrees. The situation is shown
in Fig. 4.10. While this ideal path may not be followed (it imposes
considerable restrictions on dates and times of lunar missions, and
takes no account of solar flare incidence) the general principles
involved are clear, and a lunar mission is unlikely to incur
a high dose burden from the van Allen belts on its way from and
to the Earth.

-- Vince