SLA question

During all the Lunar Apollo missions, the panels of the SLA (Spacecraft
Lunar module Adaptor) were jettisoned from the S-IVb during the T&D
(Transposition and Docking); but, as the panels were travelling along the
same trajectory as the rest of the spacecraft, did any of the panels crash
into the moon?

On Wed, 13 Aug 2008 17:37:52 GMT, "Alan Erskine"
wrote:

During all the Lunar Apollo missions, the panels of the SLA (Spacecraft
Lunar module Adaptor) were jettisoned from the S-IVb during the T&D
(Transposition and Docking); but, as the panels were travelling along the
same trajectory as the rest of the spacecraft, did any of the panels crash
into the moon?

That's an interesting question. I don't know, but I would guess
not. On most (all?) of the missions, the S-IVb required a maneuver
(usually, I think, a propellant dump) to put it on a collision course.

When the panels were released, they had some "lateral" motion to them.
If that was only 1 fps, they would be about 45 miles from the original
trajectory 65 hours later, about when the spacecraft was getting ready
to go into orbit. I don't think that was a big enough difference to
put them on a collision course...

take care,
Scott

Scott Stevenson wrote:

When the panels were released, they had some "lateral" motion to them.
If that was only 1 fps, they would be about 45 miles from the original
trajectory 65 hours later, about when the spacecraft was getting ready
to go into orbit. I don't think that was a big enough difference to
put them on a collision course...

And of course the Apollo CSM/LM wasn't sent on a collision course with
the Moon, but rather one to brake itself into orbit around the Moon.
Still that means that some of the SLA panels should be in solar orbit,
like at least one of the S-IVB's ended up.

Pat

"Scott Stevenson" wrote in message
...
That's an interesting question. I don't know, but I would guess
not. On most (all?) of the missions, the S-IVb required a maneuver
(usually, I think, a propellant dump) to put it on a collision course.

When the panels were released, they had some "lateral" motion to them.
If that was only 1 fps, they would be about 45 miles from the original
trajectory 65 hours later, about when the spacecraft was getting ready
to go into orbit. I don't think that was a big enough difference to
put them on a collision course...

take care,
Scott


I was curious about that. Thanks for the info.

"Pat Flannery" wrote in message
news


Scott Stevenson wrote:

When the panels were released, they had some "lateral" motion to them.
If that was only 1 fps, they would be about 45 miles from the original
trajectory 65 hours later, about when the spacecraft was getting ready
to go into orbit. I don't think that was a big enough difference to
put them on a collision course...

And of course the Apollo CSM/LM wasn't sent on a collision course with the
Moon, but rather one to brake itself into orbit around the Moon.
Still that means that some of the SLA panels should be in solar orbit,
like at least one of the S-IVB's ended up.

I wonder if the panel's trajectories were plotted for safety reasons....

"Alan Erskine" wrote in message
...
"Scott Stevenson" wrote in message
...
That's an interesting question. I don't know, but I would guess
not. On most (all?) of the missions, the S-IVb required a maneuver
(usually, I think, a propellant dump) to put it on a collision course.

When the panels were released, they had some "lateral" motion to them.
If that was only 1 fps, they would be about 45 miles from the original
trajectory 65 hours later, about when the spacecraft was getting ready
to go into orbit. I don't think that was a big enough difference to
put them on a collision course...

take care,
Scott


I was curious about that. Thanks for the info.

Wasn't one panel observed by Apollo 12 later in the flight?






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Greg Moore
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"Greg D. Moore (Strider)" wrote in message
m...
Wasn't one panel observed by Apollo 12 later in the flight?

That's one of the things I'm wondering about, but I was more interested in
the safety aspect.

However, could the panels (and the S-IVb for that matter) make stellar
observation more difficult? However, the panels would have been tumbling,
so their albido would have varied quite a bit - that would be noticed and
quite distinctive.

Alan Erskine wrote:
I wonder if the panel's trajectories were plotted for safety reasons....


They did have one "UFO" sighting from the Apollo 11 CM that was thought
to be a SLA panel that was floating fairly close to them (by space
standards, its size would make it visable from over a hundred miles
away). Buzz Aldrin said he thought it had a "L" shape when examined
through binoculars IIRC.
I should have remembered this...because of that incident, later Apollo
flights hinged the SLA panels outwards, but left them attached to the
S-IVB, so they only had to worry about one object in regards to a
accidental collision, rather than five.
That was one of the minor slips in the "Apollo 13" movie, where they
show the panels floating free of the S-IVB.
I seem to remember video taken by a earth-based telescope at the time of
Apollo 11 that showed the CSM/LM stack, S-IVB, and the four SLA panels
as they traveled through space toward the Moon; the SLA panels were
flashing as they tumbled end-over-end in the sunlight.

Pat

Greg D. Moore (Strider) wrote:
I was curious about that. Thanks for the info.


Wasn't one panel observed by Apollo 12 later in the flight?


Here's some photos of Apollos and SLAs taken from observatories:
http://www.astr.ua.edu/keel/space/apollo.html
Now, on these ones it shows that Apollo 13 _did_ jettison its SLA panels.

Pat

In message tatelephone
Pat Flannery wrote:

Greg D. Moore (Strider) wrote:
I was curious about that. Thanks for the info.

Wasn't one panel observed by Apollo 12 later in the flight?


Here's some photos of Apollos and SLAs taken from observatories:
http://www.astr.ua.edu/keel/space/apollo.html
Now, on these ones it shows that Apollo 13 _did_ jettison its SLA panels.

I did think it had been the other way round. Originally they were going
to be hinged, but on one of the early flights (without LM) a panel stuck
halfway so after that they were jettisoned. They went back to hinged for
the Skylab flights.

Anthony