NASA cover-up of STS forced landings?

[tblaxland]

Cheers for that, mate. Looking at it (tho it's only one page) I can't see any different criteria for EDW and KSC either.

This link (from my post above) will download the full 2000+ pages of generic mission flight rules:
http://www.jsc.nasa.gov/news/columbia/fr_generic.pdf

Plenty of goodies in there

 

[Urwumpe]

BTW... who says that 195 KEAS is standard by any means? The value should depend largely on other conditions, most notable the payload mass. Just look at the statistics (you can download them from NASA), only very few flights landed at exactly 195 KEAS.

 

[Belisarius]

Who says? Wayne Hale, former Shuttle Flight Director for 41 missions (1988-2003), deputy manager Space Shuttle program (2003-2005) and manager of the Space Shuttle Program (2005-2008). I repeat the quote from his blog, quoted above. Have a good look:

"195 knots which is the standard target"

Director of Shuttle Program not a good enough authority? Danny Deger, in charge of training Shuttle pilots for approach and landing says of Steve Nagel's landing of the STS-37:

"He planned to land on speed, 195 knots..."

It's clear from the context that they're referring to the standard minimum velocity for landing, with a special exception of 185 knots for an especially lightweight Orbiter.

About the maximum acceptable speeds, the complete Flight Rules, referenced by tblaxland above, say:

"The 214 KGS predicted touchdown speed limit is based on providing a minimum of 11 KTS margin from the 225 KGS orbiter tire certification limit given in the Orbiter Vehicle End Item Specification."

This gives us an absolute safety envelope for landing speeds of 185-225 knots, with a preferred range of 195-214 knots.
Other landings have certainly been outside these ranges, but by NASA's own rules, they weren't safe landings. Meaning the crew was lucky to walk away from them.

 

[Urwumpe]

This gives us an absolute safety envelope for landing speeds of 185-225 knots, with a preferred range of 195-214 knots.
Other landings have certainly been outside these ranges, but by NASA's own rules, they weren't safe landings. Meaning the crew was lucky to walk away from them.

Does not work with the statistical values. Most landings are at 190 KEAS. Knots ground speed are the tire safety limit, knots equivalent air speed (including wind) are the minimum lift limit.

I don't have the final wind speeds during touch down to calculate ground speed, but again, 195 KEAS is obviously NOT the fixed hard goal.

Also, there is a quotation of Bob Cabana in one of my books, which says that the nominal landing speed of a heavy loaded space Shuttle, like on STS-65, was 203 KEAS, with slightly slower being considered better. He promised to land with 198 KEAS and landed finally with 199 KEAS.

The landing speed is also confirmed by the statistical values.

So, weight has, very obviously, something to do with the nominal landing speed.

Of course STS-31 and STS-37 are anomalies in the landing speed, as they are extreme lows, but the third lowest landing speed is already STS-1. What all such landings have in common: They had been done by very light orbiters.

STS-31 and STS-37 weighted less than 191,000 lbs during landing.

The heaviest landing was STS-73, with 230,469.3 lbs and 214 KEAS landing speed.

Maybe it would be useful for the SSU project, when I do a data analysis, while I can't use Orbiter anymore.

 

[Belisarius]

There isn't really a discrepancy here, I believe. Just a little confusion about the terminology.

When they refer to 195 knots, they are not talking about the nominal touchdown speed, which could easily be 205 or thereabouts, right in the lower-middle of the safety envelope, but about the lowest possible touchdown speed before the Orbiter loses lift, stalls out, and the rear flap impacts the ground.

Weight obviously does matter in considering the minimum touchdown speed, as stated previously. That is clearly indicated in the Hale piece to be dependent on weight, with 195 being standard and 185 being considered the absolute minimum for an underweight Orbiter.

I've checked the NASA stats on landing as you suggested, and in this case there IS a discrepancy. Hale clearly states that he looked at the descent profile analysis "official numbers" and it read 176 knots on touchdown for STS-31. He also states that the commander called him and chewed him out for making him touch down at such a dangerously slow speed. Hale is not a fantastist, he's a credible source. The incident was maybe not all that serious, but rather indicative of the NASA tendency to paper over the cracks when it comes to safety issues.

Meanwhile the official story about STS-37 is dangerously suspect. They say the Orbiter came down 600 feet short, which is not good at all. But Deger, another credible source, says they were 1600 ft or 480 metres short. 600 ft or 1600 ft? In this case the incident could have been very serious indeed. Hale refuses to specify what went on, but drops some very dark hints.

Maybe you prefer to trust the stats but I prefer to trust the testimonies of the people involved here, providing I can get some evidence for them.

BTW, all of this discussion shows that in any case the safe landing speed range is almost incredibly narrow, logically enough given the Shuttle's poor aerodynamic profile. The original Maxime Faget design for the STS wouldn't have had these razor-thin tolerances.

 

[Urwumpe]

Maybe you prefer to trust the stats but I prefer to trust the testimonies of the people involved here, providing I can get some evidence for them.

I prefer to trust numbers from many sources. Not just one and not just some strange blog. The statistical numbers are fitting to accounts from other sources, so they are credible, even in extreme situations. But the question is, which quantity does Hale talk about and is Hale really correctly quoted.

Also, one thing, you have wrong in your post: Delta wings don't stall like normal air planes do. They gradually loose lift, until they drop like a stone, and are subject to strong ground effects.

The Shuttle has thus a wider margin for landing speeds, as normal airliners and you should not apply airliner knowledge to Shuttle landings. The Shuttle does not land like an airliner. It does not even land like a typical glider. It approaches faster and looses speed during the pre-flare and flare phase faster as anything else on this planet. And as it has only one try for landing, lands at much higher speeds as minimal needed - that's why it even has to include runway length into it's energy management.

 

[Belisarius]

I certainly don't trust one uncorroborated source - if I did I wouldn't have started this thread in the first place. I'm looking for evidence to support or refute the claims I outlined right at the beginning.

And I wouldn't call Hale's blog "strange". For one thing, it's hosted on the official NASA website, as you can see from the address. For another, Wayne Hale is not some wacko in a trench coat, he's the former Shuttle Program Manager and is now NASA's deputy associate administrator for strategic partnerships (dunno what that means, but it sounds rather important.) He was Flight Director on 41 missions! And for a third thing, his blog is very well written, with signs of a clear, sharp intelligence and good sense of humour. And no sign of some grudge to pay back against his employer.

For some background on him, see:
http://www.thespacereview.com/article/1069/1
http://www.thespacereview.com/article/709/1

If you have a moment, I'd really recommend you to check his blog out.

Meanwhile, as I said above, the NASA stats seem suspect to me. Take the one you quoted above for STS-37:168 KEAS at MGTD (But 161 KEAS at Threshold).

So it accelerated from threshold to touchdown, yet there is no sign of wind activity in the landing part of the vid, no dust whipping up, nothing. You just said the Orbiter loses speed in the pre-flare and flare phase, but this one didn't, according to the stats... it gained speed! Much more likely is that these stats are faulty.

Meanwhile, I've already written the article I had in mind, and I'm just polishing it up. Thanks a lot for your input, U.

 

[simonpro]

Forget put-down. Let's go with unthinking knee-jerk and most unhelpful response.

No problems, I can occasionally come across as aggressive on here though, don't take it personally if I do that to you, it's usually just me typing a reply very quickly and not thinking about how it sounds

lets hope that it is a small book

Around 450 pages, iirc.

Reviewing the flight rules (available here and summary page 2-32 attached for reference) doesn't show any difference between KSC and EDW (unless I am reading it wrong).

I haven't time to read it in detail, but a quick skim brings up several areas with notes such as this:

FOR KSC EOM ONLY, NO-GO CONSIDERATION WILL BE GIVEN TO
CLOUD LAYERS BELOW 8K FT BEING REPORTED BY GROUND WEATHER
OBSERVERS OR WEATHER AIRCRAFT GREATER THAN 2/8 COVERAGE
AND LESS THAN OR EQUAL TO 4/8 COVERAGE (SCATTERED) AT THE
DEORBIT BURN GO/NO-GO DECISION TIME

There's another example on that page and a few more a couple of pages later.

(edit)
STS-31 unquestionably touched down short of velocity, and some of the crew had a lot of rather vocal things to say about it, just as the first article in this thread suggests. In addition to the sources mentioned above I've heard it first hand from one of those involved, and second hand from a bunch of others. Not much use as a reference, but hopefully it adds weight to what you're trying to say.

 

[Belisarius]

I knew you were a good guy really. Flame wars are over, time to kiss and make up... eace:

Re the Flight Rules on weather. I've combed through them and the only differences I can see between Edwards and Kennedy are in criteria for cloud cover. The criteria for winds and turbulence are the same.

Re the personal anecdotes. Would you be willing to give me a few more details? Since Hale already names himself and the Commander in his version, further names aren't really necessary. But any details you can give can help to track down further evidence. Old invesigative journo habits, you know...

Thanks for your help.

 

[Urwumpe]

Meanwhile, as I said above, the NASA stats seem suspect to me. Take the one you quoted above for STS-37:168 KEAS at MGTD (But 161 KEAS at Threshold).

So it accelerated from threshold to touchdown, yet there is no sign of wind activity in the landing part of the vid, no dust whipping up, nothing. You just said the Orbiter loses speed in the pre-flare and flare phase, but this one didn't, according to the stats... it gained speed! Much more likely is that these stats are faulty.

No, the stats could also contain more information, when interpreted different as a faulty number:

What if the orbiter touched down before the runway threshold?

I don't want to discredit Hale, with my critical approach, but I consider such blogs as oral history. And as such, they are often not automatically absolutely wrong, but incomplete and biased.

And anyway: Any landing, from which you can walk away, is a good landing.

 

[Belisarius]

Any landing, from which you can walk away, is a good landing.

You got that right. Let's hope it stays that way with the Shuttle.

Anyway, article nearly done now. Already posted a cheesy version of it on my Spanish website. Now who's gonna pay me some good money to publish it?

 

[simonpro]

Re the Flight Rules on weather. I've combed through them and the only differences I can see between Edwards and Kennedy are in criteria for cloud cover. The criteria for winds and turbulence are the same.

I saw a difference in the crosswinds as well, but can't find it now. Will look tomorrow when at work.

Re the personal anecdotes. Would you be willing to give me a few more details? Since Hale already names himself and the Commander in his version, further names aren't really necessary. But any details you can give can help to track down further evidence. Old invesigative journo habits, you know...

Well my story from the crew comes first hand from McCandless. But I've heard the same story (crew angry with the F.D) from two flight directors (indirectly) and (first hand) from a bunch of other JSC employees who have engineering jobs, mainly on the ISS project. A number used to work on the shuttle though.
I've also heard the story in a presentation by Gene Kranz. He was talking about how crews and flight directors can have differences of opinion and gave some examples from his time in the hotseat and also mentioned something like "problem still exists today, such as STS 31, STS 94 and Mir/STS 84". No specifics from him though.

 

[Belisarius]

That's spot on. Thanks for the info.

 

[Kyle]

STS-123 landed to fast, that's all I have ever heard about landing issue besides Columbia.

 

[DaveS]

STS-123 landed to fast, that's all I have ever heard about landing issue besides Columbia.

Where did you get that from? Endeavour landed just fine, with a nominal drag-chute deploy by the PLT shortly after MLG touchdown.

Please state your source.

 

[garyw]

Where did you get that from? Endeavour landed just fine, with a nominal drag-chute deploy by the PLT shortly after MLG touchdown.

Please state your source.

STS-123 touched down at about 195 knots which is the nominal speed for an ISS based mission. This was a night landing and a lot of a concern was raised about the APU "fire" coming from the top of the orbiter. In actuality everything on this landing was standard.

 

[DaveS]

STS-123 touched down at about 195 knots which is the nominal speed for an ISS based mission.

Touchdown speed is based on vehicle mass at touchdown. Heavyweight orbiters(more than 101 250 kg) is aiming for a touchdown velocity of 205 kts while lightweight orbiters (less than 92250 kg) aims for a touchdown velocity of 195 kts.

 

[Donamy]

I don't see why a pilot would have to stretch a glide(very bad to do) if he knew he was underspeed before the HAC. He would just fly a smaller HAC to make up the energy.

 

[Belisarius]

I don't see why a pilot would have to stretch a glide(very bad to do) if he knew he was underspeed before the HAC. He would just fly a smaller HAC to make up the energy.

If you're referring to STS-37, this link quoted by Redburne explains why the HAC went screwy
http://sci.tech-archive.net/Archive/.../msg00059.html

Quote:
"The winds are such that 20 knots of precious airspeed is lost at 7,000 feet. This important call was made to the ground and discussed at length in the Mission Control Center. But for some reason, Steve Nagel, who was the commander of STS-37, was not told about the wind shear.
Steve and his crew performed the deorbit burn and let the computers fly the shuttle down to Mach 1. At this point Steve took over. Unfortunately, Steve had to fly a right hand turn to the lakebed runway. He had been scheduled for a left hand turn on the concrete runway, so almost all of his training was with left hand turns. The flight director needles commanded him to start his turn, so he did. Now Steve made a mistake. He was so interested in finding the runway early he started to look outside. Because his seat was on the left, he couldn't see the runway until very late. Meanwhile, the shuttle flew into a tail wind and commanded Steve into the maximum bank allowed - 60 degrees. Steve missed the command and maintains the more normal 45 degrees. Without knowing it, the shuttle was flying wide and losing energy fast."

 

[Donamy]

You could hardly call that pilot error.