Observation on TPS damage on Orbiter

NASA photos | 2-3-03 | BoneMccoy

[computermechanic]

Hyper-velocity re-entry viewing opportunity around Jan 15:

NASA site:
http://reentry.arc.nasa.gov/viewingforum.html

Mentioned by:
http://www.spaceweather.com/
(BTW, you might want to bookmark this site)

[tubebender]

The good news...I live in Eureka Ca. 90 miles south of Crescent City. The bad news...It's our monsoon season and cloud cover is guranteed.

Convert UTC time to Eureka time for me...

[tubebender]

I see it's around 2 AM so I will set my alarm and get up and check.

[Cold Heat]

Looks like I will miss out, unless I decide to jump into the SUV and head West....

Should be interesting to see!

[computermechanic]

Just FYI, from the site:

"As long as there is no thunder, a passing storm should not interfer with the sonic boom observations. Cloudy weather does not affect the sonic boom adversely. The boom will be louder if it is wet."

http://reentry.arc.nasa.gov/viewingforum.html


BTW, From the same URL:

"Heat Shields for Manned Missions:
As the plans for manned exploration of the Moon and Mars progress, reliable heatshield materials are needed to return the astronauts safely back to Earth. How the SRC heatshield reacts to the high velocity will help in determining if it is the right material for these future missions."

[computermechanic]

Columbia unsolved puzzle, 08:52:32 Off-nominal Supply water dump nozzle temperature sensors A and B.


Perhaps the explaination is:

a) 08:52:32 a.m. Temperature rising: Enough plasma "raced right and left down the hollow RCC leading-edge panels" finally reaching sensors 33 & 34, enough to start showing the measured temperature increases.

b) 08:52:47 a.m. Temperature falling: The wing spar has been significantly breached and the plasma is no longer forced "UP" the RCC-panels toward sensors 33 & 34, but the plasma instead has an "easier" path continuing thru the wing.

Once the plasma is in the RCC leading-edge "channel" the plasma has picked up the shuttle's forward velocity and can now travel a few feet per second "faster" than the shuttle in order to travel up to the nose (even at 18,000mph there are no relativistic effects preventing velocity increases to the plasma).


These times are very close to what CAIB had determined that the wing spar had been breached...

http://www.ksc.nasa.gov/columbia/caib0506brief.htm
"Next chart. All right. These are the first measurements that we start to see go off line. So at this point here, 5216, we know the wing spar has been breached and that we are burning wire bundles."

---

http://www.aviationnow.com/avnow/spSec/sts107_03143.jsp
Investigators believe if tile was knocked off a carrier panel at the lower RCC/wing interface, the hot plasma could have eaten away the aluminum plate and entered the wing leading edge, where it would have raced right and left down the hollow RCC leading-edge panels, eroding the steel RCC attach points-allowing the RCC to fall off or cave back into the large wing box.

---

08:52:32 Supply water dump nozzle temperature sensors A and B show temporary increase in temperature rise rate, then return to normal profile.

08:52:47 a.m. Supply water dump nozzle temperature sensors A and B return to normal rise rate.

---

http://www.ksc.nasa.gov/columbia/caib0506brief.htm
Next chart. Now, this is something different; and we can't really explain this yet. We've tried to get our thermal folks to explain it; they can't. We've tried to get our instrumentation folks to explain this instrumentation failure, and they can't. We did not see this data until we got the MADS data, but there is a temperature measurement up where the chin panel and the nose cap attach and one of those measurements began an off-nominal rise. If you look at the plot of the data, you'll see it going on a normal kind of slope and then it takes a jump, a higher heating rate, and then for some reason it cools back down and joins where it would have been at that time if it had just kept going and continues on its way.

So we don't know what to make of that either physically -- it's hard to explain something heating up and then cooling down and getting back to exactly where it would have been if it had kept on its same rise rate -- but instrumentation-wise it's also difficult to explain it. It's different than the vent nozzle temperatures that we talked before from the OI data. There when you see a higher heating rate and they cool back down again, they're offset from their slope where they would have been. So that extra heat stayed there and they're a higher temperature but at the same rate. Here it actually comes back to the same temperature it would have been and then resumes. So it's kind of odd, and we don't know how to explain that.

[Cold Heat]

I think your idea that the plasma heat moved forward and heated the nose area is a likely explanation....Sort of a bloom of plasma at some point during the wing penetration and destruction. The sensor picked it up...

Nice to see you guys are still thinking about this....

Just thought I'd let you know I got the ping.:-)

[RadioAstronomer]

Thanks for the ping. Been a while since I looked at this.