Vertical Wind Shear and the Challenger Disaster

By: 24hourprof , 1:16 PM GMT on January 30, 2013

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There's been plenty of fodder for blogs this week (snow from a nuclear plant, severe weather), but I didn't want January to end without remembering the Challenger disaster on January 28, 1986 (video).

Given the historical significance of this tragedy and the role that vertical wind shear (the topic of yesterday's blog) played as a contributing factor, I believe that the Challenger disaster is a legitimate topic to address here. At the very least, I'm hoping to convey to you that vertical wind shear has more than one application in the real world, particularly as it relates to aviation.

The Challenger Disaster

On the morning of January 28, 1986, I remember gathering with colleagues in an office adjacent to the Weather Station here on Penn State's campus and watching the live broadcast of the liftoff (Christa McAuliffe was slated to be the first teacher in space, and there was great national interest in this shuttle mission). It was clearly one of those "where were you when" moments that stand out in my life.



The 12Z temperature and dew-point soundings from Cape Canaveral, Florida, on January 28, 1986 (the morning of the Challenger disaster). Note the vertical profile of winds on the right of the image. Courtesy of the University of Wyoming

Big Florida Chill

Shown above are the 12Z temperature and dew-point soundings at Cape Canaveral, Florida, on January 28, 1986, the morning of the disaster. At the time, the surface temperature was well below 0 degrees Celsius, indicative of the unseasonably cold air mass over the Southeast States on this date. Check out the 12Z surface analysis from the NOAA archive of Daily Weather Maps and note the sprawling high-pressure system centered over the eastern Gulf of Mexico (which promoted a clear sky and light winds). In his book, Challenger, A Major Malfunction, Malcolm McConnell reports a temperature of 24 degrees at 7 A.M. EST as the "coldest period of the long night." Icicles as long as 18 inches were observed on the shuttle's support structure.

The temperature at liftoff later that morning was only 36 degrees Fahrenheit, by far the coldest launch to date in the shuttle program. The 12Z reanalysis of 500-mb heights showed a full-latitude trough over the eastern United States, which was consistent with a cold snap over Florida.

Not surprisingly, the 12Z reanalysis of 850-mb temperatures indicated readings below 0 degrees Celsius over east-central Florida, which is quite cold compared to the 850-mb climatology for the date. Granted, this climatology from the Earth System Research Laboratory is based on data from 1968 to 1996 (some of these data came after the disaster), but the long-term average 850-mb temperatures shown on the ESRL reanalysis are close to what would have been considered "climatology" on January 28, 1986. At the very least, this climatology of 850-mb temperatures should give you a better sense for the severity of the cold snap.

I'll begin my story with the controversy leading up to the liftoff (read more). The debate about whether to postpone the launch due to cold weather focused pretty much on the "resiliency" of the rubber O-rings that sealed the joints of the solid-rocket boosters. Engineers at Morton Thiokol pointed out that the capability of O-rings to operate efficiently would be reduced at air temperatures lower than 53 degrees Fahrenheit, but their objections were overruled by Thiokol management. Just before liftoff, there was already gray smoke leaking through an O-ring on the right solid-rocket booster, indicating that the seal was not operating properly (photograph).

Vertical Wind Shear

Okay, let's get the the issue at hand...vertical wind shear. Revisit the skew-T above and note the strong winds at high altitudes shown on the right of the skew-T above. According to telemetry, Challenger disintegrated at about 46,000 feet, which is roughly 14,000 meters. If you compare this altitude to the 12Z raw rawinsonde data from the University of Wyoming, you get the sense that things went terribly wrong around 150 mb. Note the rather rapid change in wind speeds with altitude in the upper troposphere. Prior to liftoff, pilots conducting test flights reported some vertical wind shear earlier that morning, but it was within acceptable limits. Obviously, vertical wind shear must have dramatically increased after 12Z (conditions were considerably worse during liftoff). According to the President's Commission Report:

"At approximately 37 seconds, Challenger encountered the first of several high-altitude wind shear conditions, which lasted until about 64 seconds. The wind shear created forces on the vehicle with relatively large fluctuations. These were immediately sensed and countered by the guidance, navigation and control system.

The steering system (thrust vector control) of the Solid Rocket Booster responded to all commands and wind shear effects. The wind shear caused the steering system to be more active than on any previous flight."


You can read more about the investigation that followed the Challenger disaster in this NASA's report (pdf file).


A series of photographs showing flame emerging from the malfunctioning O-rings. Apparently, the O-rings that had leaked smoke on the launch pad before liftoff had formed a working seal after being heated, but the aerodynamic forces associated with strong vertical wind shear likely broke these seals, allowing flame to escape to the outer surfaces of the right solid-rocket booster and setting the stage for Challenger's destruction. Courtesy of NASA and aerospaceweb.org

I also recommend the very informative account at aerospaceweb.org. Below is a specific reference (from this Web site) that directly connects wind shear to the failure of the O-rings. The context of this excerpt is a follow-up to the cloud of gray smoke observed while Challenger was still on the launch pad (right before liftoff).

"Nevertheless, no further puffs of smoke were observed since the joint apparently sealed itself. This new seal was probably due to a combination of two factors. First, the O-rings were heated by the hot burning fuel within the booster which would've increased their temperature and resiliency. This behavior is actually common in many military missiles. Such missiles often generate large clouds of black smoke at ignition due to a temporary blow-by of their O-rings that is sealed as the rings heat up. Second, the solid rocket propellant contains particles of aluminum oxide that melt when heated, and the solidifying aluminum droplets probably sealed the gap. Indeed, laboratory tests have shown that damaged O-rings with notches cut into them can be sealed by such droplets.

The temporary seal apparently remained intact for nearly one minute into the flight since the chamber pressure within the right SRB remained normal. It is very possible that this seal could have been maintained indefinitely if not for the fourth and final factor that doomed the mission. At 56 seconds after launch, right around the time of max q, Challenger passed through the worst wind shear in the history of the Shuttle program. The wind loads on the vehicle caused the booster to flex and dislodged the aluminum oxide plug that had sealed the damaged O-rings. This event was marked by a reduction in chamber pressure and the appearance of a small flickering flame that emerged from the aft field joint at 58.788 seconds Mission Elapsed Time (revisit the series of photographs above)."


In short, aerodynamic forces generated by vertical wind shear broke the temporary O-ring seals. Clearly, vertical wind shear was a contributing factor to the Challenger disaster.

Lee

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35. WunderAlertBot (Admin)
3:18 PM GMT on February 02, 2013
24hourprof has created a new entry.
34. 24hourprof
2:53 PM GMT on February 02, 2013
Quoting georgevandenberghe:
I should clarify comment 30 last sentence that it's private company management that I have issues with. I've always thought highly of NASA.


Understood.
Member Since: October 24, 2012 Posts: 91 Comments: 803
33. georgevandenberghe
3:02 AM GMT on February 02, 2013
I should clarify comment 30 last sentence that it's private company management that I have issues with. I've always thought highly of NASA.
Member Since: February 1, 2012 Posts: 19 Comments: 1933
32. 24hourprof
10:13 PM GMT on February 01, 2013
Quoting DFWdad:
Regarding my comment about "experimental not operational"....

Seems like I read that somewhere, but I cannot find it searching the internet.

I found this link to "Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident, Chapter VIII: Pressures on the System."

Link

It talks about the pressures involved to make the shuttle operational, and the philosophy of Operational versus Experimental designations. It may have been somewhere else in the Rogers report, that said NASA should always consider the Shuttle experimental. If I could find a PDF of the entire report, and had more time, I might could find it.

But certainly, from many aspects, the shuttle was operational, and I have immense respect for NASA.


Thanks for the clarification. And I share your sentiments about NASA. Great respect for what they do.

I remember living through Apollo 13, thinking that the astronauts were doomed. It was indeed "NASA's finest moment."

Every time I watch the movie, Apollo 13, I know I lived through it, but I'm still riveted to the television.
Member Since: October 24, 2012 Posts: 91 Comments: 803
31. 24hourprof
10:10 PM GMT on February 01, 2013
Quoting PedleyCA:
Excellent blog, Never knew about the wind shear issue. Should have never taken off in those two conditions. The temperature and the shear. Sometimes
people just don't think or care. The managers sure should have held liable for
their screw-up.


Many thanks for your kind words.

Like many things in life, hindsight is always 20-20. I guess that's why they call it the human condition.
Member Since: October 24, 2012 Posts: 91 Comments: 803
30. georgevandenberghe
7:28 PM GMT on February 01, 2013
My only contribution to this thread is that I was in Tallahassee during the Challenger disaster and can attest that in Florida, this was a severe arctic outbreak with intensity seen a few times per decade. I don't remember the weather numbers but do remember the shock of the incident and a nagging suspicion that it wasn't immediately fatal for the astronauts made it even more horrible to contemplate.

It does raise the question, at lower stratospheric levels what causes intense wind shear and tight wind shear gradients and temporal changes? Grid point models of the time (the NGM) had a 60km resolution and should have been able to resolve things with a length scale of 300km; below that issues would arise. Or should we be looking at and for things like vertically propagating gravity waves which are difficult to initialize even today although we can resolve them?

My understanding also about Columbia is that the heat tile damage would have resulted in disintegration even in the absence of shear.

The Challenger incident seeded a contempt in me for American management which remains to this day
Member Since: February 1, 2012 Posts: 19 Comments: 1933
29. ChillinInTheKeys
5:30 PM GMT on February 01, 2013
Quoting PedleyCA:
Excellent blog, Never knew about the wind shear issue. Should have never taken off in those two conditions. The temperature and the shear. Sometimes
people just don't think or care. The managers sure should have held liable for
their screw-up.


Challenger launch...

"Prior to liftoff, pilots conducting test flights reported some vertical wind shear earlier that morning, but it was within acceptable limits. Obviously, vertical wind shear must have dramatically increased after 12Z (conditions were considerably worse during liftoff). According to the President's Commission Report:"

As for the Columbia, was the shear encountered on lift off or re-entry? If it were the latter the shuttle had to navigate through thousands of miles of atmosphere. The weather couldn't possibly be ideal along the entire length of the re-entry path.
Member Since: August 18, 2008 Posts: 0 Comments: 695
28. DFWdad
5:19 PM GMT on February 01, 2013
Regarding my comment about "experimental not operational"....

Seems like I read that somewhere, but I cannot find it searching the internet.

I found this link to "Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident, Chapter VIII: Pressures on the System."

Link

It talks about the pressures involved to make the shuttle operational, and the philosophy of Operational versus Experimental designations. It may have been somewhere else in the Rogers report, that said NASA should always consider the Shuttle experimental. If I could find a PDF of the entire report, and had more time, I might could find it.

But certainly, from many aspects, the shuttle was operational, and I have immense respect for NASA.
Member Since: November 5, 2012 Posts: 0 Comments: 209
27. PedleyCA
5:11 PM GMT on February 01, 2013
Excellent blog, Never knew about the wind shear issue. Should have never taken off in those two conditions. The temperature and the shear. Sometimes
people just don't think or care. The managers sure should have held liable for
their screw-up.
Member Since: February 29, 2012 Posts: 0 Comments: 6000
26. 24hourprof
4:44 PM GMT on February 01, 2013
Quoting DFWdad:
Thanks! Never knew the role the wind shear played in the accident. So, while the engineers for the boosters pressed for a delay in launch, they really still had some room for error in their design, since the military rockets deal with the same issue. But it was flying into unknown shear conditions.

Its no wonder the shuttle program never progressed from 'experimental' to 'operational'. Even though NASA's preparation is unparalleled, just not enough iterations to uncover and reduce all of the risks in space flight.


You're quite welcome.

I never knew that about the Shuttle's "experimental" status.
Member Since: October 24, 2012 Posts: 91 Comments: 803
25. DFWdad
4:34 PM GMT on February 01, 2013
Thanks! Never knew the role the wind shear played in the accident. So, while the engineers for the boosters pressed for a delay in launch, they really still had some room for error in their design, since the military rockets deal with the same issue. But it was flying into unknown shear conditions.

Its no wonder the shuttle program never progressed from 'experimental' to 'operational'. Even though NASA's preparation is unparalleled, just not enough iterations to uncover and reduce all of the risks in space flight.
Member Since: November 5, 2012 Posts: 0 Comments: 209
24. 24hourprof
4:32 PM GMT on February 01, 2013
Quoting ChillinInTheKeys:
GeorgiaStormz posted this radar image on Dr Masters blog of the debris from Columbia.



Yes, I remember looking at similar images. It sends a shiver down my back.

Many thanks for posting.

Member Since: October 24, 2012 Posts: 91 Comments: 803
23. ChillinInTheKeys
4:25 PM GMT on February 01, 2013
GeorgiaStormz posted this radar image on Dr Masters blog showing the debris from Columbia.

Member Since: August 18, 2008 Posts: 0 Comments: 695
22. 24hourprof
4:20 PM GMT on February 01, 2013
Quoting pcola57:


Hats off to you Lee..
Your absolutely correct..
I checked the report and it states the damage was terminal..
I wonder if anything at all could have been done..
Probably not as the facts seem to point out the levity of such damage..
Can't help but wonder though..
Thanks for taking the time.. :)


You're quite welcome. And I agree...I think there was nothing that could have been done.
Member Since: October 24, 2012 Posts: 91 Comments: 803
21. pcola57
4:17 PM GMT on February 01, 2013
Quoting 24hourprof:


That's a great question. I'm not completely sure, but I remember that a piece of foam insulation broke off at liftoff and hit one of the wings of Columbia. If I remember correctly, there was damage to the thermal tiles protecting Columbia. The bottom line is that such damage made it more susceptible to break-up as Columbia re-entered the atmosphere. You might want to check my "facts" to make sure I'm remembering correctly.


Hats off to you Lee..
Your absolutely correct..
I checked the report and it states the damage was terminal..
I wonder if anything at all could have been done..
Probably not as the facts seem to point out the levity of such damage..
Can't help but wonder though..
Thanks for taking the time.. :)
Member Since: August 13, 2009 Posts: 13 Comments: 6878
20. ChillinInTheKeys
4:15 PM GMT on February 01, 2013
Good morning Lee.
Dr masters posted this on his blog a few minutes ago. I imagine you'll be getting a lot more visits today. Thanks again for all the interesting posts. Very educational though some go over my head.

Oh and you'll notice he's got the date confused with the Columbia disaster.

"Lee Grenci has a post on how wind shear may have contributed to the Challenger disaster ten years ago:"

Link


Jeff Masters"

Member Since: August 18, 2008 Posts: 0 Comments: 695
19. 24hourprof
4:09 PM GMT on February 01, 2013
Quoting pcola57:
Thanks for the professional analysis Lee..
What a tremendous loss...
These were the best of the best..
I wonder why the shear risk factors learned from the Challenger disaster weren't utilized for the Columbia re-entry..


That's a great question. I'm not completely sure, but I remember that a piece of foam insulation broke off at liftoff and hit one of the wings of Columbia. If I remember correctly, there was damage to the thermal tiles protecting Columbia. The bottom line is that such damage made it more susceptible to break-up as Columbia re-entered the atmosphere. You might want to check my "facts" to make sure I'm remembering correctly.
Member Since: October 24, 2012 Posts: 91 Comments: 803
18. pcola57
3:51 PM GMT on February 01, 2013
Thanks for the professional analysis Lee..
What a tremendous loss...
These were the best of the best..
I wonder why the shear risk factors learned from the Challenger disaster weren't utilized for the Columbia re-entry..
Member Since: August 13, 2009 Posts: 13 Comments: 6878
17. 24hourprof
12:35 PM GMT on February 01, 2013
Quoting whitewabit:
Very interesting about the shear .. Doc had a interesting question on the orientation of the shuttle ..


Many thanks. I think aerospace.org had the correct answer.
Member Since: October 24, 2012 Posts: 91 Comments: 803
16. 24hourprof
12:33 PM GMT on February 01, 2013
Quoting DocNDswamp:
Lee, thanks for your response (and since, read the full account at aerospaceweb link provided), appears 2nd guess was more accurate.

And from following other links, ironically enough, realized today marks the 10th anniversary of Columbia tragedy in 2003 - a clear, calm Feb 1st, perfect for observing it's passage overhead SE LA, expected at 8:02 AM locally enroute to KSC... by 8:04, obvious something amiss, fears escalating soon after as - even at 400 miles downstream - heard 5 deep, distant "booms" in quick succession, every dog around began barking. Back inside to the live telecast to learn communications lost... soon after the horrific videos capturing the break-up overhead TX.

And wind shear a contributing factor in both disasters, as stated in aerospaceweb account - "While there is by no means any direct link between these two accidents, it is interesting to note that one of the key factors in the Challenger disaster was the worst wind shear ever experienced by a Shuttle, and Columbia happened to experience the second worst wind shear in history, a factor that played a key role in its eventual loss as well."


I had forgotten about the wind shear associated with the Columbia tragedy. Thanks for reminding me.
Member Since: October 24, 2012 Posts: 91 Comments: 803
15. whitewabit (Mod)
7:37 AM GMT on February 01, 2013
Very interesting about the shear .. Doc had a interesting question on the orientation of the shuttle ..
Member Since: August 17, 2005 Posts: 365 Comments: 31743
14. DocNDswamp
7:15 AM GMT on February 01, 2013
Lee, thanks for your response (and since, read the full account at aerospaceweb link provided), appears 2nd guess was more accurate.

And from following other links, ironically enough, realized today marks the 10th anniversary of Columbia tragedy in 2003 - a clear, calm Feb 1st, perfect for observing it's passage overhead SE LA, expected at 8:02 AM locally enroute to KSC... by 8:04, obvious something amiss, fears escalating soon after as - even at 400 miles downstream - heard 5 deep, distant "booms" in quick succession, every dog around began barking. Back inside to the live telecast to learn communications lost... soon after the horrific videos capturing the break-up overhead TX.

And wind shear a contributing factor in both disasters, as stated in aerospaceweb account - "While there is by no means any direct link between these two accidents, it is interesting to note that one of the key factors in the Challenger disaster was the worst wind shear ever experienced by a Shuttle, and Columbia happened to experience the second worst wind shear in history, a factor that played a key role in its eventual loss as well."
Member Since: September 21, 2005 Posts: 94 Comments: 4794
13. 24hourprof
7:09 PM GMT on January 31, 2013
Quoting DocNDswamp:
Very interesting Lee, thanks.
Indeed, the "where were you" aspect, vividly remember who told me, the job was working on, etc... Too shocked to concentrate, we quit early that day, went home to watch sad news reports.

Noting how the tell-tale flame is deflected to the right in the imagery, curious if the vehicle's orientation to the upper level shearing wind offers supporting evidence as appears.. Seems unlikely, but perhaps I'm making a leaping assumption, confusing this with normal design / expected aerodynamic flow?



Here's what aerospace.org says:

Vehicle Destruction:

The flame continued to grow and became caught up in the aerodynamic flowfield of the accelerating Shuttle. Had this flame been pointed in nearly any other direction, the Shuttle probably could have continued flying safely until booster separation, since the booster continued operating even after the rest of the vehicle had disintegrated. With the loss in chamber pressure, however, the booster would have produced insufficent thrust to push the Shuttle into its proper orbit, and the Orbiter would have had to make an emergency landing at one of its abort sites.

Since the flame was pointed directly towards the ET, however, it impinged on the SRB's supporting strut and the surface of the ET causing both to be serverely weakened. The liquid hydrogen tank soon began leaking resulting in a loss in pressure at 66.764 seconds MET. The leaking liquid hydrogen instantly vaporized into its gaseous state and was made visible by a cloud of vapor seen emanating from the ET. The escaping hydrogen also fed the flame from the right SRB causing it to change color and become even more pronounced at 64.660 seconds. Shortly thereafter, a bright sustained glow developed on the black-tiled underside of the Orbiter. At 70 seconds MET, a circumferential leak of hydrogen appeared about a third of the way up from the bottom of the ET indicating that the hydrogen inner tank had failed and the ET was disintegrating.


Liquid hydrogen leaking from the External Tank

The final breakup of the vehicle began around 72 seconds when a rapid series of events was set into motion. At 72.204 seconds, the lower struct connecting the right SRB to the ET finally gave way and allowed the booster to rotate around the upper attachment strut. This rotation was indicated by a sudden change in pitch and yaw rates between the left and right boosters.

At 73.124 seconds, cameras recorded a circumferential white vapor pattern blooming from the side of the bottom dome on the ET indicating that a structural failure was in progress. This failure soon resulted in the entire aft dome of the ET dropping away from the rest of the tank to release massive amounts of liquid hydrogen. The loss of so much mass created a sudden surge in acceleration that actually pushed the hydrogen tank upward into the region separating it from the oxygen tank at the top of the ET. Simultaneously, the rotating right SRB impacted the lower part of the liquid oxygen tank causing it to fail. This collision was later confirmed when impact damage was discovered on the conical SRB nose cone after it was recovered. The failure of the oxygen tank occurred at 73.137 seconds as evidenced by white vapors appearing in the region.
Member Since: October 24, 2012 Posts: 91 Comments: 803
11. DocNDswamp
5:09 PM GMT on January 31, 2013
Very interesting Lee, thanks.
Indeed, the "where were you" aspect, vividly remember who told me, the job was working on, etc... Too shocked to concentrate, we quit early that day, went home to watch sad news reports.

Noting how the tell-tale flame is deflected to the right in the imagery, curious if the vehicle's orientation to the upper level shearing wind offers supporting evidence as appears.. Seems unlikely, but perhaps I'm making a leaping assumption, confusing this with normal design / expected aerodynamic flow?

Member Since: September 21, 2005 Posts: 94 Comments: 4794
10. 24hourprof
9:30 PM GMT on January 30, 2013
Quoting ChillinInTheKeys:


Thanks!!! Just like everything in life, it's been an adventure! And yes, the say that the explosion at that altitude exerted no more than a couple of pounds of pressure on the cabin and it's likely they were very aware of what was happening. I still don't understand the cover up and the sneaking of the bodies in. I think the general public could've handled the facts.


Agreed.
Member Since: October 24, 2012 Posts: 91 Comments: 803
9. ChillinInTheKeys
9:27 PM GMT on January 30, 2013
Quoting 24hourprof:


I knew immediately that something was dreadfully wrong. I've read where the astronauts probably survived the initial disintegration, but the impact on the water at great speeds was simply not survivable. As a teacher, I was in awe of Christa McAullife ("I touch the future; I teach").

On a happier note, congratulations! 28 years is quite amazing.


Thanks!!! Just like everything in life, it's been an adventure! And yes, they say that the explosion at that altitude exerted no more than a couple of pounds of pressure on the cabin and it's likely they were very aware of what was happening. I still don't understand the cover up and the sneaking of the bodies in. I think the general public could've handled the facts.
Member Since: August 18, 2008 Posts: 0 Comments: 695
8. 24hourprof
8:54 PM GMT on January 30, 2013
Quoting ChillinInTheKeys:
Yes, a very interesting post. This is the first time that I have heard about the shear. I watch this live from the roof of our shop in Ft Lauderdale arguing with my cousins that it had just blown up as I had seen several launches, they said no it had "just separated". I guess we were both correct. This happened on our 1st wedding anniversary and made for an interesting celebration. Well we made 28 years this past Monday.


I knew immediately that something was dreadfully wrong. I've read where the astronauts probably survived the initial disintegration, but the impact on the water at great speeds was simply not survivable. As a teacher, I was in awe of Christa McAullife ("I touch the future; I teach").

On a happier note, congratulations! 28 years is quite amazing.
Member Since: October 24, 2012 Posts: 91 Comments: 803
7. 24hourprof
8:47 PM GMT on January 30, 2013
Quoting mobal:
Very interesting and informative. There are many fascinating historical events that are directly related to weather.


Many thanks for the kind words. Yes, indeed, the impacts of weather are everywhere.
Member Since: October 24, 2012 Posts: 91 Comments: 803
6. 24hourprof
8:46 PM GMT on January 30, 2013
Quoting JNCali:
Thank you Prof. Lee.. Watching that launch unfold was traumatic.. I had not come across the wind shear info before. I could not believe it when I found out about the Blackbird leaking fuel all over the place when not flying fast enough to heat/expand its structure enough for its seals to work correctly, Thanks again..


I still remember going to class right after the disaster. I started to teach, but my heart wasn't in it. So I dismissed class.
Member Since: October 24, 2012 Posts: 91 Comments: 803
5. 24hourprof
8:44 PM GMT on January 30, 2013
Quoting WunderGirl12:
This is very interesting. :-) I liked your photos of the shuttle. Poor Challenger...

Got a quick question for you. What exactly is a tropical wave off the west coast of Africa? I can't seem to figure that out...

WunderGirl2


Ah, fodder for another blog. Thanks.
Member Since: October 24, 2012 Posts: 91 Comments: 803
4. ChillinInTheKeys
6:25 PM GMT on January 30, 2013
Yes, a very interesting post. This is the first time that I have heard about the shear. I watch this live from the roof of our shop in Ft Lauderdale arguing with my cousins that it had just blown up as I had seen several launches, they said no it had "just separated". I guess we were both correct. This happened on our 1st wedding anniversary and made for an interesting celebration. Well we made 28 years this past Monday.
Member Since: August 18, 2008 Posts: 0 Comments: 695
3. mobal
6:11 PM GMT on January 30, 2013
Very interesting and informative. There are many fascinating historical events that are directly related to weather.
Member Since: August 3, 2005 Posts: 482 Comments: 5333
2. JNCali
4:53 PM GMT on January 30, 2013
Thank you Prof. Lee.. Watching that launch unfold was traumatic.. I had not come across the wind shear info before. I could not believe it when I found out about the Blackbird leaking fuel all over the place when not flying fast enough to heat/expand its structure enough for its seals to work correctly, Thanks again..
Member Since: September 9, 2010 Posts: 5 Comments: 1034
1. WunderGirl12
1:22 PM GMT on January 30, 2013
This is very interesting. :-) I liked your photos of the shuttle. Poor Challenger...

Got a quick question for you. What exactly is a tropical wave off the west coast of Africa? I can't seem to figure that out...

WunderGirl2
Member Since: January 9, 2011 Posts: 24 Comments: 812

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