NASA-UAP-D005: Apollo 17 Crew Debriefing for Science (1973)

MSC-07632

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APOLLO 17
-CREW DEBRIEFING
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FOR SCIENCE

JANUARY 8, 1973

SIGNATOR LOC
I\JS
oso-44,=:-

MANNED SPACECRAFT CENTER
HOUSTON.TEXAS

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HENRY
(CONT 'D)

gravitationally holding it together°
in the form of ionized hydrogen.

We though it might be

We looked for Lyman-alpha

radiation, red shifted from the ionized hydrogen, and we
didn't see any.

We set a lower limit, which certainly ex-

cludes the possibility that the Coma cluster is held together
J
by this ionized hydrogen.

I think that may leave a real

mystery as to what is holding the thing together.

The fourth point may turn out to be the most interesting
thing of all.

When you look in the Milky Way, you see a

lot of UV coming from the stars, but the question is, what
do you see when you look up to the North Galactic Pole or
down to the South Galactic Pole.

One of the most exciting

results of X-ray astronomy was the fact that an X-ray background was observed over the sky that nobody had expected,
and part of this is the gamma-ray background that Dr. Trombka
talked about.

In the UV, nobody knows, but you never know

until you look.

You do have to deal with this background

of stars that we know is there.

So we did look at a large

number of different points at high galactic latitudes, both
.

north and south.
dark count.

The spectrum that we see is above this

In other words, this abnormally high dark

current did not, in fact, interfere with that experiment.
The spectrum that we see looks like the spectrum of the hot

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HENRY
(CONT'D)

star; however, we know that there were no hot stars within
our field of view.

Therefore, the most conservative inter-

pretation, I think, is that what we're seeing is light from
hot stars in the galactic plane going up out of the plane
and reflecting off interstellar dust.

There are certain

characteristics of the spectrum, though, that don't fit that
theory, and it's at least possible that this is extragalactic
radiation.

I'm looking forward very much to the detailed

computer study of this, but it's going to take a long time.

Fifth point:

Lyman-alpha hydrogen radiation is a completely

separate problem, and Gary Thomas at the University of
Colorado and Charles Barthum [?] observed this from OGO-5.
We obtained Just an enormous amount of data on the Apollo
that's going to straighten out this picture and clarify it
considerably.
system.

This is hydrogen that is inside our solar

It's sunlight reflecting off this.

The hydrogen,

Gary Thomas thinks, is hydrogen from interstellar space
streaming through the solar system, and he is looking forward with great anticipation to getting detailed analyses
of that.

One more thing:

the spectrum of the Earth.

I keep saying

"we ? " but these were the guys that were there.
at the Earth from outside.

We looked

A lot of people have observed