Examine hull before re-entry, a new standard procedure?

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

inexpensive tiny TV cameras... can fly attached
to the exterior of the shuttle....to examine the
hull's integrity...

I don't think you could get a good view of the underside of
the shuttle from cameras that are mounted directly to the
surface, as they'd be viewing the surface at almost a right
angle. They would have to be held several feet away on a
boom of some sort to get a good view.

Plus, I don't think NASA would look favorably on the idea of
external cameras that would detach during reentry, because
of the possibility of them damaging the tiles, either at the
moment of separation, or if they tumbled in the airstream
and impacted on the shuttle.

A better approach might be to modify the shuttle arm so that
a camera on it could examine the wings and underside of
the shuttle. And if the camera's on the arm, you've got
the additional advantage that it can be repositioned at will to
get the best possible view of a trouble spot.

Jim

(Ross C. Bubba Nicholson) wrote in
m:

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

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

I said:
A better approach might be to modify the shuttle arm
so that a camera on it could examine the wings and
underside of the shuttle...

Herb replied:
And if you'd been reading along at home for more
than a few days, this is exactly what those with
the most inside information have been saying...

Herb, I'm not sure if your comment was directed at me,
or at the person who posted the original question. If it
was directed at me, I certainly am aware that this idea
has been discussed previously. I wasn't trying to imply
that it was a new idea.

Jim

http://www.space.com/businesstechnol...ts_030209.html

"... One system, the AERCam-SPRINT has already proven its robotic right
stuff. It flew
on STS-87 in 1997."

So, you add an antenna that deploys from the canister over the side of
the orbiter. Why are we making this so complicated?

"Jorge R. Frank" wrote:


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.


--
The Rule of Abi-Bar-Shim (Project Mgr. - Great Pyramid):

"At some point it becomes necessary to behead all the architects and
begin construction."

eof

On Tue, 8 Jul 2003 20:41:34 GMT, Bruce Treffinger
wrote:

http://www.space.com/businesstechnol...ts_030209.html

"... One system, the AERCam-SPRINT has already proven its robotic right
stuff. It flew
on STS-87 in 1997."

So, you add an antenna that deploys from the canister over the side of
the orbiter. Why are we making this so complicated?

The antenna could itself damage the Orbiter's TPS. A better idea is an
antenna mounted on the end of the RMS.

Brian

"Ross C. Bubba Nicholson" wrote in message
om...

We do not know that Columbia was disabled at
launch, it could have happened in space.

I think it's safe to say now that, by far, teh most likely cause fo the
accident was the foamstrike.

Free-flying video camera robots can meet all these objections. First,
how about a lens cap, an anti-static spray, - a defogger or just
deploy more cameras?

just make sure that all those cameras are safely mounted (gotta test
everything thoroughly) so *they* don't fall off and impact the orbiter with
evcen more force than the foam they are monitoring.

Now, an escape pod in the shuttle might be a good idea, too, eh?

only if you don't need to carry any cargo. BTW...*what* escape pod? Gotta
design one basically from scratch, take a decade. We goona ground the
shuttle fleet that long?

Flying the shuttle, crew could eject into the pod and let the shuttle
land itself a la Buran. It would extend the lifespan of the shuttle
fleet if descents can not be man-rated, which they certainly cannot be
without complete inspections.

what makes you think an unmanned descent profile would be any more likely to
preserve the orbiter than a manned profile? Unmanned pulls *more* G and heat
loads, not less...

Repairs can be effected in orbit.

sure, just roll down the window and look for the nearest Home Depot

--
Terrell Miller


"We pay for love, but the hate comes free"
-Gordon Sumner

We do not know that Columbia was disabled at
launch, it could have happened in space.

I think it's safe to say now that, by far, teh most likely cause fo the
accident was the foamstrike.


If a future shuttle were struck by spacejunk just large enough to endanger the
TPS, would the crew even know of the impact? Should sensors of some kind be
introduced for that kind of an emergency?

escape pod in the shuttle might be a good idea, too, eh?

only if you don't need to carry any cargo. BTW...*what* escape pod? Gotta
design one basically from scratch,

Escape pods were probably never doable. AIUI, every aircraft that had them was
*designed* to use them. Has any aircraft ever been retrofitted with pods that
then functioned successfully?

you think an unmanned descent profile would be any more likely to
preserve the orbiter than a manned profile? Unmanned pulls *more* G and heat
loads,

.....not to mention there would be a gaping hole in the shuttle's nose where the
lifepods had been. The orbiter would become unrecoverable, even by remote
piloting.

"Jorge R. Frank" wrote in message
...

No, it's not. If the expendable cameras can't communicate with the
orbiter,
they're useless. NASA is going to have to solve the underside comm problem
for EVA repair,

....which is probably a very KISS-able fix, just put an off-the-shelf
transponder package into something that can be mounted to RMS during the
EVA. It's not a question of difficulty, just that it wasn't there for
STS107.

Sure, but Columbia didn't approach ISS, did they? Oops.

Most future shuttle missions will go to ISS. There are only two non-ISS
flights on the manifest for the remainder of the shuttle program, both to
the Hubble Space Telescope. They are far enough in the future that near-
term attention is concentrated on an inspection/repair solution for ISS
flights. A standalone solution can come later.

but in reality will probably keep getting shelved, then forgotten. NASA will
just ignore the risk on the non-ISS flights.


Now, an escape pod in the shuttle might be a good idea, too, eh?
Flying the shuttle, crew could eject into the pod and let the shuttle
land itself a la Buran.

Buran had auto-land capability, but did not have escape pods.

It would extend the lifespan of the shuttle
fleet if descents can not be man-rated,

No, it would not. There are numerous failure modes during entry that
require crew intervention, up to and including manual flying, for the
vehicle to survive.

not to mention that the gear deploy is manual, and designing an auto system
adds another crit-1 level of complexity to the current design.

--
Terrell Miller


"We pay for love, but the hate comes free"
-Gordon Sumner