Add OEX-type recorders to remaining shuttles?

[Reed Snellenberger]

Now that we've decided that the Shuttle is *still* a development program,
and given the value of the OEX recorder in determining what caused
Columbia's destruction, NASA ought to install a similar recording device in
the remaining three orbiters.

Although there are probably measurements that will be prohibitively
difficult to collect, the sensor wiring that we see in the pictures in this
report don't look nearly as difficult to reproduce as I had expected.
There will certainly be a several hundred pound weight penalty, but the
value of the data (i.e., accident reconstruction, hypersonic flight
research) ought to outweigh the penalty.

It makes sense to look into something a bit more hardened than the OEX
reel-to-reel recorder -- perhaps we could ask a flight data recorder
manufacturer to look into what would be required.

--
Reed Snellenberger

[Hallerb]

>
>It makes sense to look into something a bit more hardened than the OEX
>reel-to-reel recorder -- perhaps we could ask a flight data recorde

Yeah and add a voice data recorder as well.

Obviously the downlink can and does fail for a variety of reasons. The more
data the better.

[Jonathan Griffitts]

In article >, rk writes
>In general, from what I understand, recorders are going digital more and
>more. Indeed, most recent spacecraft that I am aware of have gone
>digital in a variety of memory configurations: SRAM, DRAM, EEPROM,
>Flash, etc. These memory technologies, again from what I understand as
>I haven't researched it myself, have better data integrity as a function
>of temperature than magnetic tape.

I might observe that the OEX tape recorder proved to have pretty damn
good data integrity after falling free from high altitude and speed and
taking some heating, then sitting out in the weather for some days.
I've talked to some of the Imation people who did the salvage work on
the Columbia OEX tape, and they tell me that all data was recovered
right up to the point that recording stopped. The tape was broken when
mechanical trauma smashed things across the tape path, but the break was
beyond the last valid data. A large portion of a camcorder video tape
apparently also survived the breakup and fall.

SRAM or DRAM memories might have a hard time competing with that since
they need stable power and control signals to retain their contents.
Flash or EEPROM would have a better survival chance, but tape will
always give you more storage capacity.

I suspect that the spacecraft recorders you're talking about are for
different purposes, and disaster survival isn't a requirement.


>I believe the recorders put into the
>Shuttles during OMM are going digital although Columbia's was still
>analog.

It's my impression that the OEX recorder in Columbia was digital. 28
tracks recorded on 1" tape. Several hundred channels of sensor
information (both analog and digital) merged into a single digital data
stream with timestamps.

--
Jonathan Griffitts
AnyWare Engineering Boulder, CO, USA

[Bob Niland]

> ... NASA ought to install a similar recording device in
> the remaining three orbiters.

I'd argue against this. Spend the money on preventing
losses in the first place. Lost shuttles aren't going
to be replaced now, so the imperative is loss prevention.
And given that both losses to date resulted from NASA
management flying despite evidence of out-of-spec launch
anomalies, the place to focus the investment and
attention is clear.

Further, it was just dumb luck that the OEX survived.
We could not expect a standard OEX to survice the next
Class A mishap. Engineering a DFDR that could survive
the next management-induced-disaster would be extremely
expensive, and with no assurance that the device would
actually be recovered with useful data.

Besides, if the next mishap is "stranded in orbit", it
won't matter what kind of recorder is on board.

Regards, PO Box 248
Bob Niland Enterprise
Kansas
which, due to spam, is: 67441-0248 USA
email4rjn AT yahoo DOT com
http://www.access-one.com/rjn

Unless otherwise specifically stated, expressing personal
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[Stephen Stocker]

In article >, Jonathan Griffitts wrote:
<snip>
> I might observe that the OEX tape recorder proved to have pretty damn
> good data integrity after falling free from high altitude and speed and
> taking some heating, then sitting out in the weather for some days.
> I've talked to some of the Imation people who did the salvage work on
> the Columbia OEX tape, and they tell me that all data was recovered
> right up to the point that recording stopped. The tape was broken when
> mechanical trauma smashed things across the tape path, but the break was
> beyond the last valid data. A large portion of a camcorder video tape
> apparently also survived the breakup and fall.

Was that the 13 minute tape, recorded a few minutes before the
breakup? That was amazing to me.

Steve