TogetherinParis@hotmail.com (Ross C.  Bubba  Nicholson) wrote in 
news:6a0b25a3.0307071940.482d9c9@posting.google.com:

> For a few hundred dollars, inexpensive tiny TV cameras viewable on any
> nearby PC can fly attached to the exterior of the shuttle.

Inexpensive TV cameras would be highly unlikely to have sufficient 
resolution to meet the shuttle program's "critical damage thresholds", 
which are as low as 0.25 in. for the wing leading edge lower surface.

>  Flown into
> orbit they could be used to examine the hull's integrity.  Launches do
> not encounter conditions which would disable electronic cameras
> (unlike re-entries).

The "ET cam" carried on STS-112 was fogged over by the SRB separation 
motors two minutes after liftoff, so your system would have to find a way 
to cope with that.

>  They are so inexpensive that multiple cameras
> (20 or 30) could be deployed prior to re-entry and a computer
> composite composed from their images (most of which would not have the
> shuttle in them) for careful analysis.

Waiting until prior to re-entry is not wise. By then, consumable levels are 
too low to allow much flexibility in scheduling repair EVAs, or powering 
down to stretch consumables for a rescue.

In an ascent abort scenario, how do you plan to deploy the cameras to 
prevent them from becoming a debris hazard?

Current planning for underside TV camera coverage (by EVA or free-flyers) 
is encountering problems with blockage by the orbiter structure, a problem 
that would be multiplied with a large number of cameras.

>   Encountering no air
> resistance, cameras would accompany the shuttle until it changed its
> velocity vector.  This would allow plenty of time to examine the hull
> for launch or other damage without exposing crews to routein
> spacewalks.

If the cameras are completely passive, even the slightest tipoff rates 
during deployment will result in them slowly tumbling, and only getting 
intermittent views of the orbiter. Unless the ballistic coefficients are 
carefully matched, differential drag will fairly quickly carry them from 
the vicinity of the orbiter.  And the orbiter "changes its velocity vector" 
almost continuously; the RCS thrusters that it uses for attitude control 
are cross-coupled into translation.

>  A passive system, you could "flush them down the toilet"
> and out into space using them where they would be recaptured by the
> atmosphere, thus posing no danger to subsequent missions.

They would remain in orbit for at least some amount of time, and form a 
space debris hazard. Again, not wise.

Now, here is what the space shuttle program is *probably* going to do for 
vehicle inspection, at least for near-term ISS flights:

On flight day 2, the shuttle RMS (which will now be carried on all flights) 
will inspect the crew compartment, OMS pods, vertical stabilizer, the upper 
leading edge of both wings except the outboard-most five panels, and the 
lower leading edge of the left wing except the outboard-most eight panels.

On flight day 3, during approach to ISS, the orbiter will perform a slow 
pitch maneuver at a range of 600 ft below the station, to allow the station 
crew to photograph the orbiter through the lab window. A DCS-760 with a 400 
mm lens will be used to photograph the "acreage" tiles, while a DCS-760 
with a 400 mm lens and a 2x doubler will be used to photograph the landing 
gear doors, ET umbilical doors, and elevon coves. An HD video camera may be 
added as well.

Post-docking, some time on flight days 3-5, the station RMS will inspect 
the nose cap, and any areas missed during the pitch maneuver except the 
right main landing gear door, ET doors, or elevon coves.

Inspection options for the right lower leading edge and wingtips are under 
consideration, such as boom extensions for the RMS/SSRMS. Should these not 
be ready for return-to-flight, EVA inspection might be required.

This plan accomplishes inspection early enough to provide lots of options 
for repair EVAs, and consumable stretch for rescue missions.

-- 
JRF

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