Author Topic: LIVE: STS-116 Landing Weather (Read 60365 times)

EW-3 · « **Reply #80 on:** 12/22/2006 08:08 am »

thank you, can you expand on that please?
why are clouds an issue? I'm being very simple minded here I know, but it seems silly to land at White Sands because of clouds.
Same question for precip. I can understand worrying about lightening or high winds that could cause real problems, but clouds and precip seems a bit weak.....

rdale · « **Reply #81 on:** 12/22/2006 08:57 am »

Clouds because you only get one chance at landing, so you want to be able to see things as early as possible. Precip because the tiles are fragile, and flying through any rain would do significant damage to the shuttle.

Dana · « **Reply #82 on:** 12/22/2006 09:12 am »

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EW-3 - 21/12/2006 10:55 PM

OK, another beginner question.
What exactly is wrong with the KSC conditions?
Low cloud deck? Why is the shuttle different than any other aircraft landing under IFR.
Is there some absolute reason, based on the laws of physics why it can't land safely?

Any other aircraft shooting an instrument approach can go around if things get messed up. The Orbiter can't.

rdale · « **Reply #83 on:** 12/22/2006 09:26 am »

I can't do a ton of forecasting since I'm filling in for our morning guy on-air this week (thank GOD it's my last day, the 2am alarm sucks let alone smiling and pretending to be happy all morning ;> ) but here's what I have so far...

KSC looks perfect at this time, and I think precip can be ruled out as much of a concern. Thickening clouds over the Gulf of Mexico are moving their way, but seeing plenty of breaks and they are primarily high clouds so I'm optimistic.

Winds at Edwards AFB have been running in the 8-12kt range, but still expected to pick up a bit later today (especially late in the afternoon.) No worries at NOR.

sawtooth · « **Reply #84 on:** 12/22/2006 10:19 am »

Quote

EW-3 - 22/12/2006 2:51 AM

thank you, can you expand on that please?
why are clouds an issue? I'm being very simple minded here I know, but it seems silly to land at White Sands because of clouds.
Same question for precip. I can understand worrying about lightening or high winds that could cause real problems, but clouds and precip seems a bit weak.....

They avoid rain for visibility reasons, to avoid water getting in the tiles and also wet runway issues. I'm fairly certain that the tiles are coated with a sealant that gets removed on re-entry so they are more like to end up with water in them if they get wet post landing which means more time under heaters to dry out the tiles. Any water trapped in the tiles would then expand to ice if they launched again without getting the tiles dry.

Remember, the de-orbit burn is done about an hour before landing IIRC, so they want to be sure showers are far enough away (30 NM) so they'll have time to land without them being a problem. A deorbit burn cannot be undone.

rdale · « **Reply #85 on:** 12/22/2006 10:42 am »

Local NWS office forecasts -

KSC: Mostly cloudy with scattered showers in the afternoon. Highs in the upper 70s. South winds 10 to 15 mph. Chance of rain 40 percent.

Edwards AFB: Partly cloudy with a 20 percent chance of showers in the morning. Highs in the 50s. Northwest winds 20 to 30 mph with local gusts to 40 mph.

White Sands: Mostly sunny, with a high near 55. Calm wind becoming south southwest between 7 and 10 mph.

USAF Forecasts -

KSC: Mostly cloudy, 40% of showers. Winds SE 15G25.

Edwards: Partly sunny with just high clouds, winds NW 15G25.

White Sands: High clouds moving in, light winds.

NWS Spaceflight Met Group forecast was not updated at 8pm last night, should be at 8am-ish today.

gordo · « **Reply #86 on:** 12/22/2006 10:57 am »

That Edwards forecast for gusts well in excess of 20knts really does not make great reading.

dutch courage · « **Reply #87 on:** 12/22/2006 11:07 am »

Will there be a special meeting to determine which landing site will be used or will the flight director decide?

gordo · « **Reply #88 on:** 12/22/2006 11:12 am »

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dutch courage - 22/12/2006 11:50 AM

Will there be a special meeting to determine which landing site will be used or will the flight director decide?

will be a real time call with what mission rules allow. loads of info avail, inc that from the crews flying the shuttle training aircraft. Remember Go for De-orbit burn to landing is a considerable time, so they need to be confident that the weather will not worsen.

EirikV · « **Reply #89 on:** 12/22/2006 11:14 am »

I'm flying gliders (or sailplanes, whatever..) and when we fly into rain/precip our range decreases, and we also have to add some knots to our final approach speed because of this (stall speed increases). I think this also would happen to a Shuttle as well (at least it makes sense to me), but raindrops hitting them at Mach 5 would probably be more serious!

Godspeed Discovery!

psloss · « **Reply #90 on:** 12/22/2006 11:22 am »

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rdale - 22/12/2006 6:25 AM

NWS Spaceflight Met Group forecast was not updated at 8pm last night, should be at 8am-ish today.

Thanks, Rob...FYI, as I noted last night they did post their forecasts on this page ("CONUS Daily Weather Sheet"):
http://www.srh.noaa.gov/smg/landfcsts_conus_pg1.html

Rocket Nut · « **Reply #91 on:** 12/22/2006 11:34 am »

The "raindrops at Mach 5" argument is quite fallacious. I hear it from NASA frequently.

The shuttle slows to below Mach 1 at 55-60,000 feet. I used to fly weather recon flights at these altitudes, and seldom saw rain clouds this high. When we did see clouds topping out at these altitudes, they were easily avoided at speeds the shuttle is flying.

I would be interested to see the probably damage to tiles at 300-500 kt speeds that the shuttle is achieving during descent at altitudes where rain is probable.

Cheers,

Larry

psloss · « **Reply #92 on:** 12/22/2006 11:46 am »

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Rocket Nut - 22/12/2006 7:17 AM

I would be interested to see the probably damage to tiles at 300-500 kt speeds that the shuttle is achieving during descent at altitudes where rain is probable.

One of Columbia's ferry flights flew through rain; I believe it was coming back from the Palmdale mods between STS-9 and 61-C...the pictures and internal reports of the damage that caused would be a good measure, since the SCA flies low.

Jim · « **Reply #93 on:** 12/22/2006 12:05 pm »

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sawtooth - 22/12/2006 6:02 AM

They avoid rain for visibility reasons, to avoid water getting in the tiles and also wet runway issues. I'm fairly certain that the tiles are coated with a sealant that gets removed on re-entry so they are more like to end up with water in them if they get wet post landing which means more time under heaters to dry out the tiles. Any water trapped in the tiles would then expand to ice if they launched again without getting the tiles dry.

It is not about the tiles absorbing rain, (too short of time). It is about impact damage. Rain on tiles is like water on sugar cubes

landofgrey · « **Reply #94 on:** 12/22/2006 02:05 pm »

A layer of (I think) altocumulous clouds followed me into the KSC area, the edge of the front. It's going to be overcast or nearly so pretty soon if movement keeps coming this way. My fingers are still crossed, but they're starting to hurt and it's hard to hold a cup of coffee this way (much less type). I was more hopeful last night.

rdale · « **Reply #95 on:** 12/22/2006 02:16 pm »

Only off by 750 miles ;> The front is in Louisiana, the closest thick clouds are fromt a line of thunderstorms about 200 miles west of Tampa. The clouds you're seeing are just random daytime clouds, with TTS reporting a broken deck at 29,000ft and just a few clouds at 12,000ft. Titusville is mostly sunny, Orlando area is mostly sunny, and Patrick AFB also has just a broken layer at 32,000ft with a few clouds below. All green.

rdale · « **Reply #96 on:** 12/22/2006 02:18 pm »

Latest from SMG:

U.S. LANDING SITES - EOM - FRIDAY 12/22/06

SHUTTLE LANDING FACILITY...KENNEDY SPACE CENTER FL
FIRST OPPORTUNITY
KSC FEW020 SCT050 BKN100 7 15016P24
CHC BKN050 CHC SHRA WI 30 NM

SECOND OPPORTUNITY
KSC FEW020 SCT050 BKN090 7 15012P18
CHC BKN050 CHC SHRA WI 30 NM

EDWARDS AIR FORCE BASE CA
FIRST OPPORTUNITY
EDW SKC 7 29016P24
MDT TURB 080 - 180

SECOND OPPORTUNITY
EDW SKC 7 30015P22
MDT TURB 080 - 180

THIRD OPPORTUNITY
EDW SKC 7 31012P18
MDT TURB 080 - 180

NORTHRUP STRIP...WHITE SANDS SPACE HARBOR NM
FIRST OPPORTUNITY
NOR SCT150 BKN200 7 18005P08

SECOND OPPORTUNITY
NOR BKN150 BKN200 7 15003P06

FLIGHT RULE VIOLATIONS:
KSC ... CIG/PRECIP
EDW ... XWIND
NOR ... NONE

Chris Bergin · « **Reply #97 on:** 12/22/2006 02:24 pm »

Where do we stand right now?

gordo · « **Reply #98 on:** 12/22/2006 02:28 pm »

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Chris Bergin - 22/12/2006 3:07 PM

Where do we stand right now?

FLIGHT RULE VIOLATIONS:
KSC ... CIG/PRECIP
EDW ... XWIND
NOR ... NONE

?

rdale · « **Reply #99 on:** 12/22/2006 02:30 pm »

As it stands NOR is GREEN, KSC is marginal (winds are 12g21) and EDW is RED (west winds at 19kts sustained with a peak of 35 knots about a half-hour ago.)