Lame CEV windows

Whats with the lame CEV windows on all the nasa drawings?
I understand the design will change a bit, but is there is technical
reason to need little tiny apollo style windows on this thing? Why cant
you build big windows like the shuttle has on a capsule?

wrote:
Whats with the lame CEV windows on all the nasa drawings?
I understand the design will change a bit, but is there is technical
reason to need little tiny apollo style windows on this thing? Why cant
you build big windows like the shuttle has on a capsule?

Cause big windows are an engineering pain and don't do much good on
something that's not designed to be landable like a VFR airplane.

You can probably still hand "fly" it in some phases, but would rely on
instruments more than looking out the windows. As such the windows are
sized for what's actually needed for important observation, fallback
manual star fixes, and a little sightseeing, ballanced against the
difficulties implied by their size.

In article . com,
wrote:
I understand the design will change a bit, but is there is technical
reason to need little tiny apollo style windows on this thing? Why cant
you build big windows like the shuttle has on a capsule?

Big windows are heavy, which matters more to a smaller vehicle, and they
are difficult to protect against the higher temperatures of a capsule
reentry. They also tend to mess up temperature control if they're pointed
at the Sun or at dark sky. They're not impossible, but you wouldn't do
them without good reason.

One reason the shuttle windows are big is because the crew needs a good
view for landing despite a configuration that requires them to sit well
back from the windows. For things like docking operations, where G-forces
are not an issue, it's better to have smaller windows and put the crew up
close to them.
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You can probably still hand "fly" it in some phases, but would rely on
instruments more than looking out the windows. As such the windows are
sized for what's actually needed for important observation, fallback
manual star fixes, and a little sightseeing, ballanced against the
difficulties implied by their size.

Windows on the CEV will certainly be used for docking maneuvers. As such,
you need an unobstructed view forward, but that doesn't require a
particularly big window, nor many windows. Because their roles are similar,
what worked for the Apollo CSM will work for CEV as well.

Jeff
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Jeff Findley wrote:
wrote in message

Windows on the CEV will certainly be used for docking maneuvers. As such,
you need an unobstructed view forward, but that doesn't require a
particularly big window, nor many windows. Because their roles are similar,
what worked for the Apollo CSM will work for CEV as well.

There's a confident simplicity to simply looking out the window and
seeing your target, but it's not the only way to do it. You could
probably do better with radar far out and a closed circuit TV sighting
system concentric to the hatch close in.

Really it seems that docking is a problem with two potential solutions:
one is to use measuring schemes that can give you high precision
distances (and derivatives) and ultimately feed into an automatic
control system, the other is to train in a simulator to hand fly it.
Safety and tradition seem to dictate doing both. Composite methods are
possible - hand flying with input from instruments, TV camera, etc, but
then looking out the window fits with simple, low chance of system
failure philosophy of manual control.

wrote in message
oups.com...
There's a confident simplicity to simply looking out the window and
seeing your target, but it's not the only way to do it. You could
probably do better with radar far out and a closed circuit TV sighting
system concentric to the hatch close in.

This is true.

Really it seems that docking is a problem with two potential solutions:
one is to use measuring schemes that can give you high precision
distances (and derivatives) and ultimately feed into an automatic
control system, the other is to train in a simulator to hand fly it.
Safety and tradition seem to dictate doing both. Composite methods are
possible - hand flying with input from instruments, TV camera, etc, but
then looking out the window fits with simple, low chance of system
failure philosophy of manual control.

One of NASA's goals for the CEV program is to perfect automated rendezvous
and docking, so that could be the primary method of docking on a manned
mission. To date, NASA has not used automated rendezvous and docking on any
of its manned spacecraft.

However, retaining the ability to do the docking by manual control would be
a good thing. Having a window or two available for manual docking certainly
seems to be one of the easiest ways to insure that the astronaut flying the
craft accurately knows the proximity, velocity, orientation, and etc. of the
target. This would also seem to permit docking with a minimum number of
required operating systems.

So I also agree that safety and tradition will likely lead to the CEV being
capable of both automated and manual docking.

Jeff
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In article ,
Jeff Findley wrote:
So I also agree that safety and tradition will likely lead to the CEV being
capable of both automated and manual docking.

Well, in theory. Remember that the shuttle is capable of both automatic
and manual landing, but in fact it has never made an automatic landing and
probably never will.
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Henry Spencer wrote:


Big windows are heavy,


heavier then an equivalent mass of aluminum or wahtever else that CEV
bulkhead would be made of? I know this was an issue on the LM, but its
skin was far thinner then the CM.

In article .com,
wrote:

Big windows are heavy,

heavier then an equivalent mass of aluminum or wahtever else that CEV
bulkhead would be made of?

I'd venture that they're exactly the same weight as an equivalent mass
of anything else.

Sorry, couldn't help myself...

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Henry Spencer wrote:
In article . com,
wrote:
I understand the design will change a bit, but is there is technical
reason to need little tiny apollo style windows on this thing? Why cant
you build big windows like the shuttle has on a capsule?

Big windows are heavy, which matters more to a smaller vehicle, and they
are difficult to protect against the higher temperatures of a capsule

As they say on submarines...windows are for tourists...

Besides, in the age of color XGA flatpanel diplays that weigh 1 pound,
who needs windows?

Tom