Shuttle To Fly Without Safety Revisions

HaloZero writes "In the face of safety concerns, NASA has decided to proceed with launching the Space Shuttle Discovery in July without changes to the external fuel tank. The article states that even though Discovery's last launch shed a huge 1-pound chunk of potentially devastating foam, they're willing to wait to change the spec on the disposable tank. The changes would modify the Ice/Frost Ramp assemblies, which prevent a buildup of ice on fuel lines and cables (as a side effect, they also have a tendency to dislodge large chunks of insulation)."

Comments

Proposal

[LiquidCoooled]

I think Nasa should coat the entire shuttle and tanks with materials cold enough to not freeze during take off and with a hard enough shell to survive the heat of re-entry.

Yes folks, I believe we should coat the tanks and shuttle body with politicians and lawyers.

Before you deride my concept as mere rambling, consider that they are now running the show anyway so we might as well make them useful.

I did a quick survey amongst the remaining engineers and technical folks at Nasa and they all consider my proposal double plus good.

Adopting the credo of Mexican bus companies

[iminplaya]

"Mejor muerto que tarde"

Flying without some of the safety changes

[flooey]

The summary is possibly a little misleading. Several safety changes have been made to the foam so far, but there are further changes they'd like to make. It's not like they're flying without any changes whatsoever. That's not to say that I completely agree with the decision, but it's an important point.

Re:Flying without some of the safety changes

[iamlucky13]

Correct. Foam pieces falling from the area in question (the ice ramp) have been observed to be too small to cause major concern, based on their calculations and testing, or will safely clear the orbiter (I forget which). They had been considering replacing the foam in this area with heaters. There has to be some sort of protection or else ice might build up. Ice hitting something at 500 mph is a lot worse than foam. I assume the combination of not wanting to add another active system (which can fail) and needing extra power supplied while sitting on the pad were contributors to this decision.

After the loss of Columbia, NASA removed a foam ramp from the tripod area that holds the external tank in place. This is where the piece that caused the damage came from. In Discovery's last flight (and I believe in some older launch videos), foam was also observed to come off the proturbence air load (PAL) ramp, which is another aerodynamic feature. This was also eliminated. Additionally, NASA is going to be flying a gentler flight profile on remaining missions (listed as "Low Q"). They lose a little bit of load capacity doing this, but the acceleration is lower and their speed is slower in the denser levels of the atmosphere.

Re:Flying without some of the safety changes

[Frequency Domain]

ice hitting something at 500 mph is a lot worse than foam.

You'd think that ice would be more dangerous than foam, but you'd be wrong. I had the pleasure of chatting last December with one of the astronauts who was doing the accident review. According to her the danger is more from relative velocity differences than from mass, since kinetic energy goes up quadratically with velocity and only linearly with mass. The problem with the foam is that it has such a low density that it decelerates very rapidly from aerodynamic drag after breaking loose. Ice, because of its much greater density, retains it's velocity and hits surfaces below at a much lower relative velocity. Given a choice between being hit by a chunk of ice at a few tens of mph, and a chunk of foam with the a tenth of the mass at hundreds of mph, you're better off with the ice.

Re:Flying without some of the safety changes

[Frequency Domain]

She specifically talked about foam vs. ice. She said that going into it, they all assumed that ice would be the greater threat because of hardness and mass, but after running lots of simulations (it was a simulation conference where I met her) they discovered that foam's propensity to rapidly decelerate made it a much greater threat in terms of KE once the shuttle picked up speed but was still in the atmosphere.

Re:Murderers!! - Hold on

[2.7182]

I dont' think you should start throwing around statements like that lightly. The bottom line is that the astronauts are volunteers , and they fully know the risks involved (i.e. that ~ 2/150 shuttles get destroyed.) They have a military mentality and are willing to risk their lives for a very special opportunity which they have worked for years to achieve. They assume that the engineers are working their hardest, which they probably are.

That's not the half of it!

[dietrollemdefender]

I know there are "love the whales" slashdotters out there...

I just can't stand all that smoke that the shuttle produces! Can't they use smokeless fuel?!? An the fact that they're using salmon to fuel those things! Yes its true! They use LOX to power it! See, they take Salmons and cream cheese to send the shuttle into space! It burns up soooooo many Salmon, that one day, they'll be extinct!

Re:Go Back to the Old Foam?

[A non-mouse Cow Herd]

You are incorrect. Please read the CAIB report (see chapter 3, part two here http://www.nasa.gov/columbia/caib/PDFS/VOL1/PART01 .PDF). The foam that destroyed Columbia was the old foam. The 'new foam' was only used on machine sprayed areas, while hand formed areas used the old foam.

Furthermore, foam loss was experienced long before the switch, including incidents which caused serious damage. Quoting from the above.

F3.27 Foam loss occurred on more than 80 percent of the 79 missions for which imagery was available to confirm or rule out foam loss. F3.28 Thirty percent of all missions lacked sufficient imagery to determine if foam had been lost.

The new foam did initially suffer from more loss and popcorning, however, it was the old foam that destroyed Columbia.

1970's cars more reliable? Pull the other one!

[bLanark]

There's no way that those old things were more reliable than a modern car. Back then, every driver was an amatuer mechanic, 'cos they broke down so often. This is when breakdown/roadside rescue services really took off, as more people became drivers without the tinkering instinct.

What those cars had was that they were ***easy to fix*** - easy to diagnose, easy to get the parts out and in, easy to obtain the parts, in fact. These days, the simple diagnostic tests do not work or cannot be performed, and as a result, you can't fix your own car. But cars today break down far less than they did back then, at least that's my recollection of it.

Here's an idea

[Opportunist]

Have the guy responsible for shuttle safety fly with 'em. I hold any bets that those shuttles will be safer than driving through downtown NY rush hour... bad example.

But I guess you get the idea.

Ask the Astronauts and Don't Get Confused by PR

[logicnazi]

It seems the only people who are really in a position to either complain or approve of these changes (morally) are the astronauts themselves. If they think the risk is worth the benefit of getting to fly earlier well who are we to say that they aren't making the right deciscion?

I mean given how many safe flights the shuttle has made without the foam causing a problem, and given the extra in fight safety measures (cameras and stuff) that have been implemented it isn't clear that the foam is the biggest risk the astronauts face. Flying into space is a very risky, unsafe buisness especially on old equitment like the space shuttle. It would be a shame if the publicity of the previous disastor meant that we spent tons of money fixing the foam problem when the total risk could have been reduced more for the same money/time by fixing other safety issues.

It is a general problem that things we have seen cause disastors seem more dangerous than those that have yet to cause any problems. However, we should not let that emotional effect get in the way of making the best safety choices. If the next shuttle blows up because we insisted on reducing the foam risk to 0 rather than doing a cost benefit analysis then the blood of the astronauts is on the hands of everyone who flipped out about the foam but wasn't going to care about other safety issues. On the other hand if fixing the foam really does decrease the risk the most per unit of money/time we than we bad better focus on that. However, as laymen the only thing we can do is trust the experts and second guessing them risks doing more harm than good.

Re:Same old story at NASA...

[iamlucky13]

Since apparently you hadn't heard, the space shuttle is being retired. Criticizing it changes nothing now. The future of manned spaceflight is not tied to the shuttle as you claim. For us Americans, it's currently tied to the CEV, which utilizes the best of both the Mercury, Gemini and Apollo programs with the best of and the lessons learned from the Space Shuttle program. Not to mention the space shuttle program had nothing to do with manned settlements on the moon or Mars. I think NASA envisioned continuing to have enough budget to operate extensive low orbit missions, in addition to manned exploration missions when the shuttle was conceived, which then is a failure of Congress and less directly us voters to provide them with the money needed.

Regarding costs, I've never seen a published comparison for operating the shuttle vs. launching Apollo missions in real dollars but according to Wikipedia, the Apollo program cost $25.4 billion ($135 billion in 2005 dollars) for 11 flights, including 6 landings. In comparison, the space shuttle program has used a total of $145 billion of NASA budget over the years, and has flown 114 missions. The average cost per mission then is $1.3 billion, but that includes R&D and construction of the shuttles and their facilities. Directly related costs per launch are quoted at only $55 million, meaning it would cost only that much to add another launch to the manifest, assuming no further problem mitigation needs to be performed. Yes, $1.3 billion is too much to justify the program, but when it was originally expected to launch 12-24 times per year (200-400 launches by now). I also want to point out that this "obvious mistake" was copied almost directly by the Russians with their Buran shuttle, which flew perfectly but was abandoned because of their limited resources, not because of the drawbacks (which we are now more keenly aware of) of a mixed cargo/crew vehicle in a side stack configuration.

My final point is that you incorrectly posit that the safety chief wanted to veto launching without the changes. He would've preferred the changes, but will apparently accept their omission since the major concern (the PAL ramp) was addressed. The decision to move forward was also endorsed by Griffin, who is a very accomplished engineer himself (a very different background than Keefe's, the former administrator). This is the way engineering works (in fact, life in general). You will never eliminate all the risks, so you figure out which ones can be addressed reasonably with your resources and you keep going.

Hold on there a darned minute

[ktappe]

First of all, the shuttle is not a "a death trap for any astronaut brave enough or foolish enough to jump in the cockpit". Only a small percentage of those who climbed in the cockpit have died. I'm sure your response will be that none should die, but that is a belief borne of complete fantasy. Which brings me to:

Second, where did you and so many others get the hooked on the delusion that space travel is or can be made completely safe? Or that astronauts/cosmonauts expect it to be completely safe? None who climb into the shuttle or a Soyuz capsule are under the delusion that they are climbing into the car for a jaunt down to the corner store. Getting up and moving at 17,500 miles per hour is dangerous, pure and simple, and for you to call any machine a "death trap" for tackling this hugely complex task is to ignore reality.

Can the shuttle be safer? Yes. Can the shuttle be made safer with the tiny budget NASA is being given and the critical ISS supply timeline and the "we must be absolutely 100% safe" political attitude being imposed? I propose that it cannot be. And if it cannot be, I concur with the others who have pointed out that we have to get this vehicle flying again so that we can "get back on the horse" and continue with the progress of our society into space.

And yes, I would fly on the shuttle today. No, it's not 100% safe. It can't be. Yes, I could well die. But I would still fly on it. And you can damn well rest assured those flying on it know they could die too and are adult enough to have made that choice consciously and willingly. It is not up to you to think you know better than they who have been training for decades for their missions.

-Kurt

I'd Simply Like to Point Out...

[dthx1138]

... That many of you are assholes. I'm sure your physical science course at Ithaca Community College gives you the necessary qualifications to fix the entire shuttle program with a two sentence /. post.

Give us engineers some fucking credit please.