Golf-Ball Sized Hail Damages Shuttle

MattSparkes writes "The Shuttles March launch has been delayed to late April after golf-ball sized hail caused 7000 pits and divots in the foam that shields the fuel tank. NASA say it's the worst damage of its kind that they have ever seen, but hail is not a new problem for the agency. In 1982, a hailstorm damaged the sensitive heat shield tiles on the Columbia's wings. The damaged tiles then absorbed about 540 kilograms of rain. Once in space, the orbiter faced the Sun to allow the tiles to dry out."

Comments

I'm Like NASA!

[Anonymous Coward]

In 1982, a hailstorm damaged the sensitive heat shield tiles on the Columbia's wings. The damaged tiles then absorbed about 540 kilograms of rain.

Just like my chevy!

I wonder if they're having problems getting the smell of stale McDonald's & whiskey out of their vehicle too.

Re:I'm Like NASA!

[Intron]

Yeah. This is going to kill the trade-in value.

Obviously

[Rob T Firefly]

NASA is not a golfer.

Re:Obviously

[CoolVibe]

Exactly 7000? Sounds like it was intentional.

(just kidding)

Re:Obviously

[MattSparkes]

Although some of the astronauts have been known to play.

Re:Obviously

[CrackedButter]

Woo, isn't NASA supposed to be a millionaire?

Re:Obviously

[aadvancedGIR]

That foam really tied the fuel tank together, did it not?

Re:Obviously

[saboola]

What they need is The Ding King!. (As Seen On TV!)

Re:Obviously

[Rob T Firefly]

You want foam? I can get you foam. Believe me, there are ways, dude..

Re:Obviously

[Farmer Tim]

Woo, isn't NASA supposed to be a millionaire?

No air in space, so it would be more accurate to say NASA is a millionvacuum.

Re:Obviously

[ajlitt]

Also, foam is not the preferred nomenclature. Insulation, please.

Re:Obviously

[racermd]

Maybe it's just me, and I don't claim to be a super-smrt - sorry, smart - rocket-scientist (because I'm not), but why don't they put the foam insulation on the inside of the fuel tank shell?

I'm sure there are reasons why they don't, but can those reasons out-weigh the problems it's causing with the foam on the outside?

Does anyone know if this has been considered? If so, why hasn't it been done, yet? Please be as specific as you can. I'm really interested in this.

Re:Obviously

[monoqlith]

Those tiles really tied the spacecraft together.

Re:Obviously

[Rei]

It's not just insulation to stop the hydrogen from boiling off; it's also an ablative TPS (Thermal Protection System) for liftoff. You'd melt the aluminium. Furthermore, I would wager that having liquid hydrogen seeping through the insulation would ruin its R-value, if the material is compatable with LH at all (I'd have to check). Plus it'd be harder (read: more expensive, slower) to apply internally. Plus it would take a redesign and recertification of the craft.

Re:Obviously

[josecanuc]

I don't know the answer to your question exactly, but I could make some educated guesses.

If the foam was on the inside, you could have problem with the fuel (O2, H2) breaking down the foam and "gumming up the works". You could have problems with chunks of foam falling off into the fuel.

A solution to that would be to put a liner over the foam, but that adds weight.

The current setup could be thought of as a liner on the inside, foam on the outside and any outer fairing removed for weight saving.

Re:Obviously

[smaddox]

F***in A.

"What foam?"

STFU Donnie, you're out of your element.

Re:Obviously

[Rei]

Yes, liners do add weight. The ET was initially painted white. They dropped the paint because 600 pounds of paint translated into notably more payload for the shuttle.

Re:Obviously

[ajlitt]

Liquid explosives... within city limits... that ain't legal either.

Re:Obviously

[KoshClassic]

One possible reason - save weight. Metal is heavier than foam. Imagine a tank similar to the current one in shape, size, and internal volume. Move the metal to the outside of the foam, you need more metal to cover the greater surface area on the outside of the resulting shape than it does on the inside of the current tank, hence more weight.

re: the liner idea - yeah, the tank was painted white for the first two or three launches. They got rid of the paint to save weight - apparently covering the foam with something relatively as light weight as paint, given the surface area involved, still added up to enough weight to make a difference. And, apparently it didn't really help keep the foam in place.

Re:Obviously

[brokenbeaker]

i think some of the Saturn stages had internal insulation...

http://www.geocities.com/launchreport/satstg5.html (the s4b stage)

http://history.nasa.gov/ap08fj/01launch_ascent.htm

(sorry, not the best links, and i don't know why this was chosen, and apparently forgotten....)

Heh, apparently hail ain't their only problem

[bad_fx]

[quote]NASA has had less serious problems with fuel tank foam as well. In 1995, a shuttle on the launch pad had to be returned to its hangar for repairs after woodpeckers punched about a dozen small holes in the tank's insulation.[/quote]

That got a bit of a chuckle; It's in the article linked from TFA.

Re:Heh, apparently hail ain't their only problem

[gbjbaanb]

Ok, so they should move the launch site to somewhere where they don't get stupidly large hailstorms, massive amounts of ice, super strong winds! (and is barren of trees, too).

I mean, is it me, or did they get sold some 'prime real estate' to build the launch centre?

Re:Heh, apparently hail ain't their only problem

[saboola]

Here ya go, right from the pedia:

Cape Canaveral

Cape Canaveral was chosen for rocket launches to take advantage of the earth's rotation. The centrifugal force of this rotation is greatest at the equator, and to take advantage of it, rockets are launched eastward, in the same direction of the earth's rotation. It is also highly desirable to have the downrange area sparsely populated, in case of accidents; an ocean is ideal for this. Although the United States has sites closer to the equator with expanses of ocean to the east of them (e.g. Hawaii, Puerto Rico), the east coast of Florida has substantial logistical advantages over these island locations. The tip of the cape is at LC-46 in Cape Canaveral Air Force Station.

Re:Heh, apparently hail ain't their only problem

[gbjbaanb]

exactly - despite there being potentially better sites, they went and placed it on the east coast of Florida. Substantial logistical advantages? Its near the shops? I mean, they ship parts all over the place.

It beats me why they couldn't have negotiated a base elsewhere on the planet that doesn't have golf-ball sized hailstones and killer woodpeckers. :)

Re:Heh, apparently hail ain't their only problem

[saboola]

I guess the logistics of it might be better now, but think about when it was being built in the late 1940s. Shipping parts now is definitely easier than shipping parts 60 years ago. Just a thought.

Re:Heh, apparently hail ain't their only problem

[susano_otter]

Puerto Rico and Hawaii have significant logistical disadvantages.

Re:Heh, apparently hail ain't their only problem

[Rei]

It's unfair just to assume that because there are problems in one place, some other place would automatically look better. Look at SpaceX. The Falcon is a nice looking rocket. I like the design. The company has worked well, and things have worked great in the US. On the atoll, for the actual launches, however? Problem after problem. The biggest single factor that seems to have led to them? Their choice of launch site, Kwajalein Atoll. Cheap. Equatorial. Storms are rarer than many other sites. No major population centers. Sounds great, right? Well, unfortunately, it's been a logistical and environmental nightmare. Logistical, because given its remoteness, if you run out of something or need to ship a part in, you have to wait a long time. Environmental because it's such a high corrosion environment due to the salt spray; leave something metal that's shiny and new out for a few weeks, and it looks like it's been there for years. According to a contact of Jeffrey Bell, concerning Army missile operations there before SpaceX, "?standard operating procedure [at the Kwajalien Atoll] was that all parts had to be electrolytically compatible and even then, all bolts got?a Teflon grease?put on them and all moving interfaces, bearings, slides, got coated in lithium grease.?"

I'll be very upset if their choice of Kwajalein kills the Falcon.

Re:Heh, apparently hail ain't their only problem

[Frumious Wombat]

A friend working for AFTAC just south of the Cape said that the reason they're always told is that in the late 50's, early 60's, Melbourne area wasn't on the Hurricane tracks. Even a couple of years ago during the bad season, they only got brushed with one. Locating it near Miami would have been a bad idea, as that gets almost all of them. (or so it seems)

Paradigm shift

[TWX]

Maybe there really is something to all of those science fiction movies that show space ports opening like a clamshell a few minutes before the spacecraft lifts off, especially if the air inside was temperature and humidity controlled. That kind of thing might have prevented Challenger's destruction and would keep any craft free from weather-related damage before takeoff...

Re:Paradigm shift

[hcdejong]

The only problem with that is keeping the clamshell (and the whole building) from being blasted to smithereens during takeoff. The noise level alone is enough to crumble concrete, add to that the temperature and pressure, and you see why rockets are usually launched in the open. True, missiles are often launched from canisters or silos, but:

1. Smaller missiles often use a cold-gas ejection system. The motor doesn't ignite until the missile is out of the canister. Some systems (e.g. Mk 41 VLS) ignite the missile in the canister. In this case, the canister consists of an inner tube that contains the missile, and a fixed outer tube. When reloading, the inner tube is replaced. This is doable for a missile, not so much for a Shuttle-sized rocket.

2. For larger missiles (ICBMs), a reusable launch site isn't the top priority. Damage to the silo is more acceptable here than for a NASA launch facility.

Re:Paradigm shift

[140Mandak262Jamuna]

ISRO has fixed launch pads and the Vehicle assembly building moves on rails out of the way for launch. NASA has a fixed Vehicle assembly building and the rocket moves on very complex tracked vehicle a few miles to the launch site. So far ISRO has not launched anything the size NASA has. The largest payload by ISRO, a six ton Low earth orbit, 1 ton Geostationery payload (quoting from memory, pardon errors) is very small compared to what NASA has done. So the building capable of assembling something the size of space shuttle cant easily move out of the way. But the could try to create a simpler building mainly to protect the vehicle without all that expensive jigs and assembly equipment that moves out of the way on the day of launch. They would not really like to have a fueled vehicle inside a building.

Re:Paradigm shift

[morgan_greywolf]

When they're not being used for spacecraft, we can use them for giant robots! "...and I'll form The Head!" *queue giant sword and majestic Voltron music*

Re:Paradigm shift

[nutshell42]

The Shuttle's launching off the Mobile Launcher Platform. Unlike a clamshell it's directly below the exhaust and it is even mobile (as the name implies; btw. the parts of the clamshell would need to be "mobile" as well, to open and close that thing, but unlike the MLP the engines wouldn't need to be 5m below the SLBs.

Re:Paradigm shift

[hcdejong]

The platform isn't an enclosed structure, so there's no pressure buildup. And they need 1.2 million litres of water to protect the platform (and the rest of the launch pad) during the launch. The water absorbs the heat and vibrations. A large fraction of the water is converted to steam in the 20 seconds or so from ignition to clearing the tower.

Re:Paradigm shift

[clickety6]

Nah... look at Thunderbirds. Q whacking great underground chamber that opens up just prior to launch. of course, you need to allow some time for all the NASA employees to exit the giant swimming pool before it slides out of the way ;-)

Re:Paradigm shift

[Mercano]

How about, say, something like this? Though I don't know how early in the countdown then need to roll back the building.

Re:Paradigm shift

[sconeu]

IIRC, that's what the shuttle facilities at Vandenberg were going to be. The stack would be raised in situ at the pad, and the "VAB" would roll away on both sides at some point during the countdown.

Re:Paradigm shift

[Lumpy]

When reloading, the inner tube is replaced. This is doable for a missile, not so much for a Shuttle-sized rocket.

Bah!, a foam or plastic sabot for the shuttle will solve that problem. Rifling the barrel will also help in the accuracy as well.

Re:Paradigm shift

[roman_mir]

For a miserly 5,000,000 per launch, I will personally setup a gigantic tent around the Shuttle and then will dismantle it about 2 hours before the launch ;)

Re:Paradigm shift

[centron]

Maybe they could just build a big umbrella over the launch site.

Seriously though, a retractable canopy wouldn't be temperature and humidity controlled, but snow, freezing rain, hail, and the like wouldn't be nearly as big a problem. Obviously you have to weigh the costs and engineering challenges of building a retractable canopy versus making the shuttle and tanks fully weather-proof, but I suspect it would be a pretty quick calculation.

Re:Paradigm shift

[josecanuc]

I thought the water was part of the sound suppression system:
http://www.nasa.gov/mission_pages/shuttle/launch/s ound-suppression-system.html

They had a problem with noise from the rocket engines reverberating off the platform and causing pressure variations near the nose of the shuttle.

The pad site itself is being damaged by the frequent heat-swings, causing the heat-resistant concrete to crack and come loose:
http://engineer.tamu.edu/news/story.php?p_news_id= 1220

Re:Paradigm shift

[DerekLyons]

Maybe there really is something to all of those science fiction movies that show space ports opening like a clamshell a few minutes before the spacecraft lifts off, especially if the air inside was temperature and humidity controlled. That kind of thing might have prevented Challenger's destruction and would keep any craft free from weather-related damage before takeoff...

Those clamshells are nice - but for any useful size of rocket they are pretty much impossibly beyond our current engineering abilities.
 
While such a clamshell might have prevented Challenger's loss - it's pretty much even odds that sooner or later we would have lost a Shuttle to O-ring blowby. The rings were failing at much higher temperatures because the real cause of the blowby (joint rotation) is temperature independent.
 
Also, it's not just the Shuttle that can be grounded by insulation damage - every cryogenic fueld rocket has insulation.

Re:Paradigm shift

[Rei]

No, they'd get clogged because NASA would just shove in enormous amounts of material, enormous amounts of material.

Re:Paradigm shift

[umbrellasd]

"Shields up, Mr. Sulu!"

Only practical way. Either that or self repairing hulls.

I do the same

[ReidMaynard]

.. faced the Sun to allow the tiles to dry..

I do the same thing with my pickup after it rains...except I didn't tile my truck.

Re:I do the same

[DeeVeeAnt]

So, how do you expect it to survive re-entry then?

Re:I do the same

[daeg]

Better to have it burn up in re-entry than have your wife get your truck in the divorce.

Rain

[saskboy]

So Columbia survived a half a ton of rain in its fragile shield, but was brought down by scarring foam. How odd space flight can be...

Re:Rain

[Anonymous Coward]

What is more shocking is the fact that they deliberately took up half a ton of water up into space.

I wonder how much such a worthless payload costs in terms of fuel needs.

Would it not have been cheaper to dry the shuttle while on earth? and spare a couple of hundred liters of fuel?

Re:Rain

[hey!]

I suppose it's because so much of engineering boils down to finding the most applicable of proven solutions. "Proven" is always relative to a set of assumptions. You might not even know what the relevant assumptions are until they are violated. It is important for engineers to pay attention to intuition, but you can't actually trust it, especially in unusual situations.

Re:Rain

[Anonymous Coward]

The fuel costs are marginal. The costs of space flight are complexity and manpower. If the tank was big enough to carry enough fuel to reach the intended orbit, it would cost way more to delay the launch than it would to carry the water up.

Re:Rain

[maxume]

http://en.wikipedia.org/wiki/Space_Shuttle
http://en.wikipedia.org/wiki/Space_Shuttle_Orbiter

The whole thing apparently weighs more than 4 million pounds at launch, with the orbiter being about 150,000 pounds and the payload being more than 50,000 pounds(there are 35,000 pounds that look like they are fuel). 1,000 pounds doesn't really seem like that big a deal, and probably needs to be factored into their payload mass tracking anyway(it seems like it would vary with humidity, etc).

Re:Rain

[LordVader717]

Not too big, but considering that it only gets 25 tons to orbit it isn't something you'd like. For the first two flights the external tanks were painted white, but they scrapped that because they could save over half a ton of payload.

Re:Rain

[maxume]

Not as a regular thing no, but I doubt that they do anything other than 'fill er up'. If that's true, they would know if it was something they needed to worry about.

Maybe they should have invested

[postbigbang]

in a few wee Kevlar umbrellas. For the price of this shading material, which they discovered they needed more than TWO DECADES AGO, they wouldn't have multi-million dollar dent problem.

Exactly how hard...

[joshetc]

Exactly how hard is it to just cover the damn thing? I would think after spending so much money on something NASA would want to take care of it...

Re:Exactly how hard...

[SydBarrett]

Uh oh, NASA forgot to put the shuttle in the garage after they got back from the mall. Their dad is gonna be SO pissed.

Re:Exactly how hard...

[decsnake]

they shoulda gone by home depot and got one of those gigantic blue tarps and covered it when they heard the weather forecast.

hey, it worked for me when I had the roof off of my house

Re:Exactly how hard...

[PPH]

I'm going to get the blue tarp contract with NASA and get rich!

Re:Exactly how hard...

[Anonymous Matt]

Exactly how hard is it to just cover the damn thing? I would think after spending so much money on something NASA would want to take care of it...

It's huge. It's not like they can just throw a giant diaper over it every time it rains.

Re:Exactly how hard...

[joshetc]

It's huge. It's not like they can just throw a giant diaper over it every time it rains. Wtf they cover entire football fields when it rains. Why exactly can't they keep it in a hanger?

hang on...

[symes]

Golf balls have bumps and divots over the surface to enable longer flight times. Surely these additional bumps will also aid the shuttle's aerodynamics?

Re:hang on...

[Paulrothrock]

Golf balls have bumps and divots over the surface to enable longer flight times. Surely these additional bumps will also aid the shuttle's aerodynamics?

Only if you're going to be whacking it with a giant hammer that's also designed to give it backspin. But that's the kind of stuff NASA wants to avoid.

Re:hang on...

[bdonalds]

Maybe...how fast does the shuttle need to spin before the Magnus effect makes a difference?

Re:hang on...

[Scutter]

Golf balls have bumps and divots over the surface to enable longer flight times. Surely these additional bumps will also aid the shuttle's aerodynamics?

I hear they're planning on painting red racing stripes on it, too, to make it go faster.

Re:hang on...

[atomicflounder]

Red stripes nothing. I think they should enlarge the tailpipes on that thang by a factor of at least twelve, add a few spoilers and some rims.

That is what you get having it in Florida

[DaveV1.0]

All those damned retirees and there golf. Worse than kids, I tell ya!

Re:That is what you get having it in Florida

[PPH]

At least there are quite a few "dent gypsies" in the area who will show up to fix it.

Re:Why is there foam on the outside of the tank?

[eln]

I'm no expert, but I'd imagine the reason they don't built it that way is weight. Heck, they even stopped painting it to save on weight.

Re:i did not read other comments

[Yggdrasil42]

I'm not sure what you found weird about that.
Lack of air pressure means that water will evaporate faster.

Re:540 kilograms of rain...

[clickclickdrone]

>Not to be anal but you cannot measure a liquid in kilograms
Sure you can. Stick a big bucket on some scales, fill it until the scales say 540Kgs. Not the best way of measuring it, to be sure, but you can do it.

Re:540 kilograms of rain...

[hunterkll]

Unless i'm mistaken... dosn't, uh, liquid have WEIGHT too? In respect of a shuttle launch --- they wouldn't care about volume... weight is most critical. Weight, mass, whatever.

Re:540 kilograms of rain...

[Lumbergh]

Yes, you can. Evidently you don't know your own metric system, or just wanted to be "cool" by taking a potshot at the Slashdot crowd, but 1 kilogram of water takes up 1 liter of volume. The two are effectively interchangeable in this instance and given that we're dealing with rocketry here, qualifying quantity by weight rather than volume is more relevant.

Re:540 kilograms of rain...

[Rakishi]

It's unlikely that they knew the volume but this being a rocket the mass was measurable. While you can calculate the volume from the mass, due to the rain not being perfectly pure and the temperature not being 4C the volume will not be exactly 540 liters even if the mass is exactly 540 kg (at room temp it'd be ~537 by my calculations).

It's global warming!

[Rotten168]

Nobody else said so I figured I would. ;)

Re:540 kilograms of rain...

[mobby_6kl]

Aircraft fuel is often measured in pounds or tons. You fail at being anal retentive.

Big Ass Shed

[sycodon]

Seems like it would not be too hard to contruct a big ass building around the launch pad to protect the shuttle from the weather. Put it on rails so that it could be pulled back the req. safe distance for launch.

Re:540 kilograms of rain...

[TheChromaticOrb]

Not to be anal but you cannot measure a liquid in kilograms, especially in a summary to a technical article. I know that most of the Slashdot crowd is not proficient in metric measurements (sigh...) but just in case you care, it should have been "540 liters"

Actually, using the mass makes more sense here, as said water volume will vary a lot with temperature and pressure during the shuttle's flight.

Face the sun to dry out?

[Armchair Dissident]

I'm confused. Why would the space shuttle's heat shields need to face the sun in order to dry out water? There's no pressure in orbit. Surely water under no pressure is vapour?

Re:Face the sun to dry out?

[imsabbel]

Evaporation enthalpy.

At 80 Kelvin, ice will be fine even in ultrahigh vacuum. So energy has to come from somewhere to allow the ice to evaporate. Those headshields are very good insulators, which leaves the sun as energy source.

Re:Face the sun to dry out?

[DanQuixote]

Not if it freezes first.

For larger missiles (ICBMs),

[wiredog]

a reusable launch site isn't the top priority. Especially as it is assumed the silo is going to get hit by an incoming MIRV, which will do more damage than any launch would do.

Re:i did not read other comments

[mapkinase]

You mean it will freeze before being blown off and evaporating in upper atmosphere?

Re:540 kilograms of rain...

[imsabbel]

Sorry, but spaceflight is one of those occassions where there is a rather distinctive difference between weight (N) and mass (kg).
Hint: in orbit, the stuff still was 540Kg, but 0N....

sounds like...

[davidsyes]

one HAILUVA problem...

Um, hail?

[LBt1st]

So am I the only one who's more concerned that Florida is getting golf-ball sized hail??

Re:Hanger Queen

[Rei]

No, it just goes to show how easily people ignorant of the difficulties of getting to orbit can make fun of those who actually have to deal with them. Rockets must be built incredibly light. Unfortunately, for the time being, this means flimsy. Even an extra coating of paint could kill the amount of payload they could take up.

Also, in constant dollars, the Apollo Saturn V stack was probably more expensive; it depends on how you do your accounting. And it, too, was vulnerable to weather. NASA was simply braver (perhaps crazier) back then. They even launched once during a thunderstorm -- Apollo 12. I love the logic of that one. There's a thunderstorm, and we have a gigantic vehicle full of explosive fuel, made of highly conductive metal. Lets have it launch so that it gets up to the charge layer, with a trail of ionized exhaust gas leading straight to the ground. ;) When it was struck by lightning, it nearly caused the termination of the mission -- knocked the fuel cells offline and scrambled the data from the navigational computer. Thankfully, the computer damage could be worked around due to an electrical engineer in Mission Control who knew a workaround.

Too Bad...

[Stormy Dragon]

Columbia wasn't still around to be on the launch pad for the inevitable "Hail, Columbia!" headlines that would have resulted.

Re:540 kilograms of rain...

[C0rinthian]

I think it is the process of GETTING it into orbit that we're discussing. The weight of payload is kinda irrelevant if you're already up there.

Re:540 kilograms of rain...

[ABoerma]

Also, as the temperature changes, the volume for a certain amount of rain will change, while its mass will remain 540kg.

Why does the shuttle sit on the pad for so long?

[Leuf]

Atlantis was moved to the pad on Feb 15th for a March 15th launch. What is it that they need to do with the shuttle once it's at the launchpad that they can't do in the VAB that takes a month to do? Roll it out there, kick the tires and light the fires.

One word:

[JazzLad]

Chrome (and lots of it) (no, the words inside () don't count :P )

Sonic wave blaster

[cl191]

I remember reading an article about the Nissan manufacturing plant in Mississippi had to face similar problems with hail storms damaging their newly built cars. Then they put sonic wave generators all around the lot pointing skyward, the sonic wave will blast the hail into smaller, more harmless pieces. Do they have similar systems in NASA/elsewhere?

I'm probably not the first to ask...

[tuxlove]

...before there were golf balls, how did people desribe hail? :)

What about speed holes?

[HeadlessNotAHorseman]

What about speed holes?

Salesman: Well I can't _give_ you the car, Krusty, but I _can_ let you
have this little number for practically nothing: only
$38,000.
[bullets hit the car]
Homer: [suspicious] Hey, what are all these holes?
Salesman: [quickly] These are speed holes. They make the car go
faster.
Homer: Oh, yeah. Speed holes!
[bullets riddle the car and smash the windshield]
Salesman: You want my advice? I think you should buy this car.