NASA brings engineer out of retirement to help find sensor glitch

From a CNN article
(http://www.cnn.com/2005/TECH/space/0...tle/index.html):

To help find the malfunction, NASA has brought out of retirement
an engineer who designed part of the sensor system back in the 1970s,
said Wayne Hale, deputy shuttle program manager.

This highlights how old the shuttle really is, and shows how hard it is to
keep aging systems going.

Jeff
--
Remove icky phrase from email address to get a valid address.

"Jeff Findley" wrote in message
...
From a CNN article
(http://www.cnn.com/2005/TECH/space/0...tle/index.html):

To help find the malfunction, NASA has brought out of retirement
an engineer who designed part of the sensor system back in the 1970s,
said Wayne Hale, deputy shuttle program manager.

This highlights how old the shuttle really is, and shows how hard it is to
keep aging systems going.

A SpaceRef article (http://www.spaceref.com/news/viewsr.html?pid=17379) that
has the following quote:

Space Shuttle Program has not formally assessed the risk of
aging and damaged wiring in accordance with NASA Procedural
Requirements (NPR) 8000.4, "Risk Assessment Procedures," or
developed a risk mitigation plan based on such an assessment.

This does not bode well.

Jeff
--
Remove icky phrase from email address to get a valid address.

Exactly what kinf of sensor is the ECO sensor?

I have seen some blcok diagrams of the total system but not a detailed
electrical schematic diagram. Is there one posted anywhere on the web?




"Jeff Findley" wrote in message
...

"Jeff Findley" wrote in message
...
From a CNN article
(http://www.cnn.com/2005/TECH/space/0...tle/index.html):

To help find the malfunction, NASA has brought out of retirement
an engineer who designed part of the sensor system back in the 1970s,
said Wayne Hale, deputy shuttle program manager.

This highlights how old the shuttle really is, and shows how hard it is
to
keep aging systems going.

A SpaceRef article (http://www.spaceref.com/news/viewsr.html?pid=17379)
that
has the following quote:

Space Shuttle Program has not formally assessed the risk of
aging and damaged wiring in accordance with NASA Procedural
Requirements (NPR) 8000.4, "Risk Assessment Procedures," or
developed a risk mitigation plan based on such an assessment.

This does not bode well.

Jeff
--
Remove icky phrase from email address to get a valid address.

"Dave" wrote in message
om...
Exactly what kinf of sensor is the ECO sensor?

I have seen some blcok diagrams of the total system but not a detailed
electrical schematic diagram. Is there one posted anywhere on the web?


I can't find an actual schematic (I'd love to see one). What I did find is
NASA document title "Sensors and Electronics, LH2/LO2 Point Level, ECO".
The sensor heads are described as "point sensor transducers".

If I had to guess a bit, I'd say each end of the already mentioned platinum
wire is connected to a pin in the sensor head. The wire loop is used as a
thermometer. Run some current through it, measure the voltage, and pass
that through the transducer. The result will be different when wet vs dry.

"Jeff Findley" wrote:

From a CNN article
(http://www.cnn.com/2005/TECH/space/0...tle/index.html):

To help find the malfunction, NASA has brought out of retirement
an engineer who designed part of the sensor system back in the 1970s,
said Wayne Hale, deputy shuttle program manager.

This highlights how old the shuttle really is, and shows how hard it is to
keep aging systems going.

Frankly, if we ever have routine spaceflight - I'd expect the same
thing. Look at the ages of some of the aircraft still in revenue
service.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:

From a CNN article
(http://www.cnn.com/2005/TECH/space/0...tle/index.html):

To help find the malfunction, NASA has brought out of retirement
an engineer who designed part of the sensor system back in the 1970s,
said Wayne Hale, deputy shuttle program manager.

This highlights how old the shuttle really is, and shows how hard it is
to
keep aging systems going.

Frankly, if we ever have routine spaceflight - I'd expect the same
thing. Look at the ages of some of the aircraft still in revenue
service.

D.


Nothing else with wings is half as complex as a shuttle.

I saw a DC-3 overhead yesterday. One of the reasons DC-3s are still in the
air is that you can fix most of one with the tools you keep in the garage.

So are we saying that the wiring problem is in fact inside the orbiter? It
would certainly explain why the other tank had a problem also, but not why
the fault is affected by the tank being full or not, as that part of the
equipment is in the tank, or would have to be to be affected. One assumes
that there is at some point a connector that demates when the tank is
jettisoned? Suspect no 1.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Jeff Findley" wrote in message
...

"Jeff Findley" wrote in message
...
From a CNN article
(http://www.cnn.com/2005/TECH/space/0...tle/index.html):

To help find the malfunction, NASA has brought out of retirement
an engineer who designed part of the sensor system back in the 1970s,
said Wayne Hale, deputy shuttle program manager.

This highlights how old the shuttle really is, and shows how hard it is
to
keep aging systems going.

A SpaceRef article (http://www.spaceref.com/news/viewsr.html?pid=17379)
that
has the following quote:

Space Shuttle Program has not formally assessed the risk of
aging and damaged wiring in accordance with NASA Procedural
Requirements (NPR) 8000.4, "Risk Assessment Procedures," or
developed a risk mitigation plan based on such an assessment.

This does not bode well.

Jeff
--
Remove icky phrase from email address to get a valid address.

"Brian Gaff" wrote in message
. uk...
So are we saying that the wiring problem is in fact inside the orbiter? It
would certainly explain why the other tank had a problem also, but not why
the fault is affected by the tank being full or not, as that part of the
equipment is in the tank, or would have to be to be affected. One assumes
that there is at some point a connector that demates when the tank is
jettisoned? Suspect no 1.

I think it's a strong possibility, that and the electronics boxes in the
orbiter that were likely made in the 70's as well. Even though they swapped
them, who's to say that there isn't similar degradation in the two units due
to heat, cold, corrosion, age, vibration, and etc.?

Jeff
--
Remove icky phrase from email address to get a valid address.

Dave wrote:
Exactly what kinf of sensor is the ECO sensor?

I have seen some blcok diagrams of the total system but not a detailed
electrical schematic diagram. Is there one posted anywhere on the web?



---clip---

Harwood/CBS has a good general description and history of the system
with photos at:
http://www.spaceflightnow.com/shuttl...716ecographic/

Another poster referenced a document by title which is available at
http://www.jsc.nasa.gov/news/columbi.../031042704.pdf

which describes the sensors in detail, eg.
"0.0005 INCH DIAMETER PLATINUM WIRE
SENSING ELEMENTS MOUNTED ON A CERAMIC FRAME."

The "FAILURE MODES EFFECTS ANALYSIS" on pg. 8 of the document is
interesing. It describes a number of false "wet" or "dry" failure modes
due to circuit and connector failures.

JJ Robinson II
Houston, TX

Jeff Findley wrote:
I think it's a strong possibility, that and the electronics boxes in the
orbiter that were likely made in the 70's as well. Even though they swapped
them, who's to say that there isn't similar degradation in the two units due
to heat, cold, corrosion, age, vibration, and etc.?


1- Why han't anyone commented that the flaky sensor exhibited strange readings
on the 13th of the month ?????
NASA could have written off that launch because it was the 13th and launched
the next day , confident the sensors would work :-) :-) :-)


2- While the electronics may be of 1970s design, it doesn't mean that they
were built in the 1970s. Many items in the shuttle were replaced with new
units of the same design. There are many stories of NASA paying the big bucks
to have small runs of old electronic parts built in order to maintain its
spare parts inventory.

3- Since the ET burns up, it is a fair bet that any electronics in the ET are new.