Apollo 13 question.

In article ,
says...
When power and heat were off after the exploson, why did the
astronauts not use their suits for warmth?

According to Lovell, they discussed just that. But without power to run
the fans that circulates air through the suits, they were afraid they
would get overheated, and then chilled even more seriously if they had to
take the suits off. So they decided not to wear them.

Was there ever an
explanation for the extra period of radio blackout?

Not that I've ever heard. The blackout period was always an estimate,
anyway, dependent on upper atmospheric conditions and such. I think it
was just Mr. Murphy, taking one last stab at increasing the perversity of
the universe to maximum...

--

Do not meddle in the affairs of dragons, for | Doug Van Dorn
thou art crunchy and taste good with ketchup |

In article ,
(Doug...) wrote:

Was there ever an
explanation for the extra period of radio blackout?

Not that I've ever heard. The blackout period was always an estimate,
anyway, dependent on upper atmospheric conditions and such.

I'd understood it was because the angle of re-entry had continued to
shallow and that threw off the last predictions for the length of the
blackout which had been based on a slightly steeper angle of attack.


Malcolm B

On 31 Aug 2003 12:02:35 -0700, (Mike) wrote:

When power and heat were off after the exploson, why did the
astronauts not use their suits for warmth?

....There were concerns about persperation soaking the inside layers of
the suits, thus providing a far more pnumonia-friendly environment
under the chilling conditions. IIRC, Swigert wound up with soaked and
swollen feet thanks to three days of wearing just socks that had
gotten rather wet from a water leak, and never did get them dried out
before landing.

Was there ever an explanation for the extra period of radio blackout?

....Best guess has always been a slower descent rate due to the lack of
cargo - read: Moon rocks - despite adding additional ballast from the
LM to the CM.


OM

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(Mike) wrote in message . com...
When power and heat were off after the exploson, why did the
astronauts not use their suits for warmth? Was there ever an
explanation for the extra period of radio blackout?
Thanks

The crew considered donning the suits. They definitely would've
provided ample insulation. But after some thought they estimated that
the accumulation of bodily sweat inside the suits would have made them
more uncomfortable than the cold. As for the short extra time in the
blackout, that was probably just a statistical fluke. It wasn't really
all that much longer than expected.

-Mark Martin

On Sun, 31 Aug 2003 22:16 +0100 (BST), (Malcolm
Bacchus) wrote:

I'd understood it was because the angle of re-entry had continued to
shallow and that threw off the last predictions for the length of the
blackout which had been based on a slightly steeper angle of attack.

Could the angle be much off, since the splashdown was 4 miles from the
carrier - one of the closest landings, IIRC.

Was there ever an
explanation for the extra period of radio blackout?

Dunno for sure, but Jim Lovell estimated that it was because they were coming a
little shallower than normal.

Mind you my source for this is Lovell's commentary track on the Apollo 13
dvd...

-A.L.

In article , bob wrote:
actually the within sight of recovery ship splashdown surprised me at the
time and continues to puzzle me as inexact as the course corrections have
always been described. It was a rare thing to see on TV, even for orbital
missions (cannot remember how many times it had happened.

Bear in mind that, whilst the course corrections are inexact, it doesn't
mean that you're going to be x miles off your aim point; it means you
can be *up to* x miles away, with x increasing as accuracy decreases.
(You're probably more likely to be about half X distance, so I suppose
it's not even across that circle, but it can be thought of as such)

If you ran enough Apollo re-entries, time and time again, you'd get a
nice dispersal of landing points within that target zone; if you waited
long enough, one would hit the recovery carrier (which would be rather
embarrassing, especially if piloted by one of the Navy men) - error can
sometime, by chance, be virtually nothing.

From the very scary Apollo By The Numbers, pp 46, and playing with the
data, the average distance to the target was some 1.6nm, and the average
distance to the recovery ship some 4.6nm (These are for Apollo 7-17, no
data for Skylab).

For Apollo 13, it was 1nm and 3.5nm; the lowest distance from target was
0.6nm, on Apollo 14 (it must be that Navy training), and there were two
other flights on 1nm (median at 1.4nm). The lowest distance from the
ship was 2.6nm, on Apollo 8; 3.5nm was about the median (the mean's
skewed by Apollo 11 coming down some 11km from the ship)

I wondered if, because of the special considerations (no rescue beacon) if
the rescue ships were more spread out, or responded more aggresively in
repositioning to tracking...

There's not much response you can do on that short a timescale g

Apollo 13, incidentally, had the fewest recovery ships & aircraft up to
that point on the program (all the later flights had fewer recovery a/c,
only A17 had fewer ships)

And I disagree with another assertion made on this thread that the extended
blackout was not really that significant. I remember it being over a third
longer than normal, though to be honest I don't remember tracking ones
thereafter, so perhaps greater varience was observed afterwards. I always
assumed that the extended blackout was the result of the challenged Apollo
13 command module electronics.

I wouldn't think so - I'm no expert, certainly not with gear of that
geriatric vintage, but generally radios either work or, er, don't. That
said, it was the hottest re-entry (75deg in the CM), so...

Whilst it may have been relatively long, there were only nine
(manned) Apollo re-entries at lunar velocities (there were a few
suborbital tests); you can get quite a bit of statistical variation
amongst nine samples, especially when a fairly nebulously understood
system (re-entry ionisation, the upper atmosphere, Jim Lovell
remembering to start breathing again and listen to the comm g) is
involved. There's going to be an outlier or two, it's not that unlikely
it happened on the "unlucky mission".

[Can't find radio blackout stats, but A13's entry duration was
reasonably short in comparison to some; not remarkable either way, fwiw]

--
-Andrew Gray

In article ,
says...
In article , bob wrote:
actually the within sight of recovery ship splashdown surprised me at the
time and continues to puzzle me as inexact as the course corrections have
always been described. It was a rare thing to see on TV, even for orbital
missions (cannot remember how many times it had happened.

Bear in mind that, whilst the course corrections are inexact, it doesn't
mean that you're going to be x miles off your aim point; it means you
can be *up to* x miles away, with x increasing as accuracy decreases.
(You're probably more likely to be about half X distance, so I suppose
it's not even across that circle, but it can be thought of as such)

I think you also have to remember that the CM computer (which was,
indeed, controlling the entry on Apollo 13) was able to adjust the bank
angle, thereby adjusting the projected landing point, during the entire
entry profile. So, even if the trajectory was a bit off-nominal, the
computer was able to "steer" the CM as close as possible to the correct
landing point using the CM's built-in lift.

--

Do not meddle in the affairs of dragons, for | Doug Van Dorn
thou art crunchy and taste good with ketchup |

Andrew Gray wrote:

In article , bob wrote:
I wondered if, because of the special considerations (no rescue beacon) if
the rescue ships were more spread out, or responded more aggresively in
repositioning to tracking...

There's not much response you can do on that short a timescale g


A carrier task force can make 25 knots good (or better). 24 hours
notice means they can move nearly 700 miles (1000 kilometers).

D.
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From Mike ):
When power and heat were off after the exploson,
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