Transterrestrial Musings

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"Watched the launch on NASA TV at work with about two dozen other engineers. The highlight of the launch was (naturally) the ET Cam -- every time the live feed switched to it, an appreciative murmur went through the crowd, and ET jettison was met with a chorus of awestruck 'Ooohs' and 'Aaahs'."

I'm not sure quotes are necessary; as this was the exact same scenario I experienced yesterday. Our group included a former astronaut. All appreciated the view from the ET Cam, and as it pitched up, a great review was provided of the underside of the orbiter. The resolution was great, but hopefully it is enough to allow cool heads to make reasoned evaluations. Onboard station, they can certainly do a more conclusive examination.

I more concerned about half-wits, who have read the CAIB and will claim that engineers (really managers) thought the foam strike of STS-107 was "in-family". Though true, those people made the decision on far less data then we have now. If they also read the CAIB report, the unexcusable loss wasn't just the ship and crew, but the failure to get conclusive data. Sounds like NASA listened to the CAIB, and has that data for this flight.

Posted by Leland at July 27, 2005 07:25 AM

I've failed to turn up an 'engineering prospective' of what the foam is for explicitly, as opposed to 'layman's perspective'. Pointers?

Because from the layman's descriptions there doesn't seem to be anything preventing either a _deliberate_ attempt to shed the foam deterministically or accept the lost maximum payload of reinforcing the _outside_ of the foam. This is accent - extraordinary measures shouldn't be required to prevent a thin metal sheath _outside_ the foam from melting. Nor would a remote detonation at, say, T-10s be a serious problem.

So... there's clearly something I don't understand. How long does the foam _have_ to be there, and what are the consequences of discarding the foam somewhat early?

Posted by Al at July 27, 2005 10:39 AM

I sincerely hope that the tile damage on Discovery is well within tolerances observed on other shuttle flights that returned safely. I haven't yet heard any news that indicates otherwise.

However, under a scenario where the Discovery would be abandoned in orbit is there a capability to attempt to bring it back unmanned? I'm fairly certain that it can automatically re-enter and glide to the point of landing, but I'm not sure about the actual landing which I believe is performed manually by an astronaut.

Another question, can the ISS accommodate two docked shuttles at once, or would the Discovery have to be undocked (presumably by an astronaut in the Discovery) to make room for another shuttle to dock with ISS to pick up the rest of the crew? If the ISS can't dock two shuttles, the scenarios for salvaging or repairing a damaged shuttle seem to get very complicated very quickly. I also assume that there is a maximum time that a shuttle can stay in orbit (powered or unpowered) before it would simply be too unsafe to attempt any type of landing.

Hopefully these aren't silly questions.

Posted by mpthompson at July 27, 2005 10:41 AM

I can see it now: Our entire shuttle fleet docked at ISS, unable to return, while all our astronauts pack into a Soyuz, like clowns in a Volkswagon, for the ride down. Meanwhile, NASA explains that they have to do this, to ensure the astronauts' safety.

I mean, if they keep one shuttle up there due to normal wear and tear, wouldn't they have to keep them all up there?

Posted by John K Berntson at July 27, 2005 11:04 AM

New images offer wealth of shuttle insight

http://www.msnbc.msn.com/id/8717609/

But what we didn't see is as important as what we did

ANALYSIS // By James Oberg, NBC News space analyst

MSNBC // Updated: 1:43 p.m. ET July 27, 2005

HOUSTON - Camera views from the space shuttle Discovery showed some spectacular scenes during launch — and some alarming ones as well. Pieces big and small fell away from the structure. Strange flares and shimmering auras gleamed against black space. With more than a hundred cameras and millions of megabits of visual data, we are seeing things we’ve never seen before.
................
The more we open our eyes, on shuttle flights and elsewhere in space, the more surprises we experience. But these results should hardly be reason for excessive worry. Keeping new eyes closed, and opting not to look, has always worried me a lot more.

Posted by Jim O at July 27, 2005 12:22 PM

I've never been too clear on what the ISS rescue scenarios are- I'm almost certain the station can't dock two shuttles, so that would be a definate hangup to leaving a crew there and having them picked up later. I'm also not sure whether the station could support a shuttle crew without a major step-up in supply flights, or if any contingency plans have been made to do so in the event the crew does have to abandon the orbiter.

As for landing unmanned, so far as I know this can't be done. The reason is- get ready for it- the landing gear has to be manually armed and deployed from the cockpit by a pilot. The astronauts argued that since landing gear deployment during reentry would be catastrophic, gear deployment should be entirely under manual control rather than automatic. As far as I know, the shuttle could perform a deorbit burn, reenter, perform TAEM, and set up for a glide in to the airstrip- whereupon it would automatically pancake in for lack of an automatic gear-deploy.

Posted by Jeff Dougherty at July 27, 2005 12:49 PM

I, too, am still on the lookout for definitive data analysis from knowledgable sources. All I've found are media pictures. I am waiting for official (or even semi-official) word on what is amiss and the severity of any problem (if there is one).

Posted by Yishai at July 27, 2005 02:11 PM

WFTV in Orlando has annouced that the shuttle fleet is now grounded indefinately by NASA. Here we go again!

Posted by Bruce at July 27, 2005 03:43 PM

Regarding the news conference today on the subject:

Parsons: "I can't say what the impact of this is." Shuttles can't fly with this large size foam coming off, he added.

Umm...is it just me, or has EVERY ONE of the OVER 100 shuttle flights so far had this sort of debris? Does this not indicate that shuttles CAN fly with this debris shedding? This completely illustrates for me the pathetic, fraidy-cat culture that has developed at NAySAy. Even more proof that now is the time for the private sector to take the reins of humanity's space flight endeavors. But that's just my opinion.

Posted by Nick B at July 27, 2005 04:10 PM

This is not good. If they can't come back home in the orbiter, then this may be the final shuttle flight, the end of ISS, the beginning of the end for Hubble, and the beginning of another period (5 years minimum) where we have no human access to space.

Posted by lmg at July 27, 2005 04:16 PM

It looks like the chunk was about the same size as the foam used in the CAIB airgun tests. Looks like Discovery literally dodged a bullet.

That begin said, there is no reason to think (at this stage) that STS-300 is going to be required. It might have reduced the number of remaining flights to.. 10?

Posted by Duncan Young at July 27, 2005 04:40 PM

I'm disturbed that after grounding the shuttle fleet for two years and spending over $1 billion on improvements the external tank is still shedding large chunks of foam. Now that the fleet is grounded for another couple of months the shuttle program will continue to gobble up hundreds of millions of dollars while doing nothing. Scratch a couple more station assembly flights possible before the 2010 retirement. It's frustrating to consider the alternative space transportation systems that could have been funded with three years worth of space shuttle budget.

Posted by John Kavanagh at July 27, 2005 04:57 PM

And of course the big funny is that all of this foam shedding didn't happen before CFCs were banned and they switched to the newer, more 'enviro friendly' foam they use now.

Posted by David Mercer at July 27, 2005 10:41 PM

You beat me to the punch David. My understanding was that the old foam formulation was better in that the pieces (that is always shed) were smaller. The new foam tends to come off in big pieces.

The other thing is, don't they always have to replace tiles after the shuttle returns? I thought that was normal operations. At what point are they critical?

Do they have the option of bringing the shuttle back with a partial crew? Chances are the shuttle will be fine and the remaining crew will be less of a logistic hassle.

This is a real black-eye for NASA.

Posted by ken anthony at July 28, 2005 02:09 AM

"this may be the final shuttle flight, the end of ISS"

How's this a bad thing ?

Posted by kert at July 28, 2005 02:11 AM

Blaming the switch from CFCs for the shuttle foam problems is a deplorable canard.

The foam that came off on Columbia's last launch was the old foam, with CFCs. They'd been having shedding problems since very early in the program, long before the blowing agent was changed.

Posted by Paul Dietz at July 28, 2005 04:01 AM

Now I'm reaching back here, but I seem to remember reading that the original foam adhesive was substituted for a lesser one very early on due to environmental regulations.

Was I just imagining it or does anyone else remember the details?

Posted by Kevin Parkin at July 28, 2005 04:22 AM

OK, scrub previous comment. Somehow I missed reading the end of the thread.

Posted by Kevin Parkin at July 28, 2005 04:25 AM

If it came to it, it certainly ought to be possible to get under the "dash", and rig the landing gear deployment to be actuated automatically; I really doubt that they're lowering it from the cockpit with a handcrank. Probably just have to swap a couple of wires.

Posted by Brett Bellmore at July 28, 2005 06:43 AM

If the landing gear can't be re-rigged, then, it would seem the best alternative would be for the shuttle to be landed with just one crewmember aboard, who wouldn't even necessarily have to be a fully-qualified shuttle pilot -- just be able to operate the landing gear at the right moment. Or am I missing something?

Posted by David Nishimura at July 28, 2005 06:53 AM

If Atlantis is grounded. Discovery is the only ride home. No Soyuz available.

Posted by Bill White at July 28, 2005 07:19 AM

So if they abondon the Shuttle upstairs, is it legally "flotsam and jetsom"? In other words, could someone claim it as abondoned property ("space junk")?

That would be a prize to encourage space entrepreneurs!

Posted by Whitehall at July 28, 2005 07:36 AM

About automatically landing the shuttle: I don't think it can be done. There is just too much hairy edge-of-the-envelope physics happening all at once.

The shuttle viewed from the landing site (not from your living-room couch) looks like a rock falling out of the sky, which it literaly is doing. Aerodynamics are employed to guide that rock to a target on the ground, but the shuttle is acting ballistically, coming down like a bomb. Computers work well in this application.

A few hundred feet from the ground, on command from the pilot, bam! the gear and flaps come down, the nose goes up, huge vortices swirl off the pathetically-stubby wings, and the craft mushes into a several-hundred MPH flare, just in time to keep itself from drilling into the Mojave. That my friends takes a pilot.

The whole process, from first sighting to touchdown takes probably less than three minutes. Everything happens so fast! I not sure if they're allowing the public in to see this shuttle landing, but if they are, you HAVE to see it! You'll have no idea of what an awesome accomplishment this is unless you do.

Posted by at July 28, 2005 09:26 AM

My friend, you have no idea what computers can do, apparently. Of course, if anything went wrong, it would take a pilot to compensate, but there's no fundamental reason the shuttle shouldn't be able to land automatically (except for that thing with the manual gear release mentioned above). Actually, I thought I heard years ago that the reasoning behind not using autoland was something related to tolerances on the tires or some such thing. Anyone able to shed light on that?

Posted by Nick B at July 28, 2005 09:51 AM

Rand,

"One Third"?..."Fleet"? How are two ships a fleet? Guess I've got a "fleet" in my garage then.

You're not laboring under the delusion that OV-100 is anything more than an air-drop mock-up, are you?

Posted by Tommy G at July 28, 2005 10:28 AM

Presumably you mean to include Dsc when you talk of the "remaining" fleet - grounding, in this case, refering only to Edv and Atl, by definition. In that case, just a quiblle with the descriptive.

Even still, "fleet"?

Posted by Tommy G at July 28, 2005 10:53 AM

I've always been bothered by calling 3 or 4 ships a "fleet". A squadron, perhaps, but a fleet?

Posted by Stewart at July 28, 2005 11:17 AM

>> Of course, if anything went wrong, it would take a pilot to compensate...

That's right, Nick B. And since we don't even trust our trolleys to automation yet, why subject our space program to the risk of failed hardware when we have a damn good pilot already on board?

(BTW, I've designed and built computers from scratch, and I understand them pretty well. It's the sensors, the actuators, and the software that worry me. Watch the shuttle landing in person if you can. There probably won't be any more.)

Posted by at July 28, 2005 12:54 PM

"The foam that came off on Columbia's last launch was the old foam, with CFCs."

The old CPR system was scrapped and the new NCFI has no CFC's. We havn't used CPR for years.

Moron.

Posted by Mike Holt at July 28, 2005 01:09 PM

Just as an aside, a pretty large reason we don't trust public forms of transportation is due to the potentially great risk to the general public in the event of a failure. Specifically referring to the shuttle, I do understand what's required of the shuttle on landing, being both a pilot, and an engineer who's dealt with aircraft and spacecraft control systems (sensors and actuators included). The control systems available are more than capable. As for dealing with the loss of an orbiter on an automated landing, I'd say that would be no worse than the current NAySAy plan, which is, as I understand it, to simply reenter the shuttle over the ocean and ditch it. And, the way I see it right now, the space program has been at risk due to hardware failures for a long, long time.

Posted by Nick B. at July 28, 2005 01:43 PM

When I say "current plan", of course I mean the contingency plan in case they decide Discovery is in no shape for manned reentry.

Posted by Nick B. at July 28, 2005 01:45 PM

The primary reason that the Orbiter has never been auto-landed has been because the idea has always been vetoed by the two guys riding just aft the front window. The ship's computers are perfectly capable of making the final approach and landing.

When the Orbiter re-enters all the "wild edge physics stuff" referenced in a previous post is handled by the ship's computers. The pilot, actually the mission commander not really the pilot, takes over in the last five or so minutes before landing.

Not to belittle the human pilots. Flying a falling rock, which the Orbiter is at that point, takes great skill and it don't make no nevermind if you are a computer or a people.

Posted by Michael at July 28, 2005 02:01 PM

Yeah, you know, I always thought it was kind of interesting that, ever since Gemini, there's never been a "co-pilot" or "first officer" or anything of the sort, only "pilots" and "commanders." I also liked the fact that the Lunar Module Pilots never actually piloted the lunar module (except for Al Bean). Just a little slightly off-topic lightening-of-the-mood post...

Posted by Nick B. at July 28, 2005 02:06 PM

Wasn't the Russian version of the Shuttle fully automated when it came to landing. I seem to remember that it had only one flight and there were no humans aboard. Didn’t I read somewhere that its landing were within some amazingly short distances from the theoretical landing point. So is it a fact that what they did with their derivation of the shuttle, the real thing can't do?

Posted by Arthur at July 28, 2005 03:06 PM

Rand wrote: "The Shuttle is damaged, but no more so than previous flights from which it has returned safely."

Thomas James wrote: "Perhaps the ET routinely sheds cable-tray foam (or whatever it ends up being identified as) with no ill effects."

That may be true. On the other hand, isn't this like the reasoning that led to the first Shuttle disaster? "We had partial burn-through of the O-rings in previous successful flights, therefore burn-through isn't a problem."

Is this shedding part of the design and expected behavior? If not, doesn't that indicate that there's a problem?

Posted by Jim C. at July 28, 2005 04:10 PM

Arthur: "Wasn't the Russian version of the Shuttle fully automated when it came to landing."

Yes, it was. I would hope NASA would be cable of the same.

Posted by Cecil Trotter at July 28, 2005 05:19 PM

"The pilot, actually the mission commander not really the pilot, takes over in the last five minutes or so before landing."

Does he? I was under the impression that the entire landing process except for landing gear arming and deployment was, or could be, completely automated. Anybody with Shuttle experience know how true this is?

I remember reading something about there having been only one manual reentry and landing in the entire Shuttle program, but that could have referred to the reentry manuever having been performed manually.

Posted by Jeff Dougherty at July 28, 2005 05:51 PM

Back in the beginning of the shuttle program, they painted the ET white. Maybe they should go back to painting the tank. Maybe the paint acts to seal the foam and keep it in place.

Whatever they do, they ought to implement fully automated landing so that they can test their solution without sending up more astronauts. Or at the very least, don't send up a full crew of 7 on the test flight.

Posted by lmg at July 28, 2005 08:29 PM

If I remember correctly, you don't fly the shuttle... you fly the computer... the computer flies the shuttle. Without the computer only a movie star pilot could land a shuttle (while firing an infinite supply of bullets from a six-gun with the only visible effects being sparks where the bullets bounce once off the interior.)

Posted by ken anthony at July 28, 2005 09:05 PM

BTW, if they decide they can't land the shuttle, what prevents them from leaving it in orbit? They might even come up with a refueling plan?

Posted by ken anthony at July 28, 2005 09:13 PM

My admittedly sparse knowledge is that the foam was changed for some time before the Columbia disaster. This seems to be an area that should be re-examined. For instance, what is the cost-benefit ratio of the environmental damage using the previous process against grounding the entire program? What exactly were the environmental effects in the first place? How important were these effects compared to the shuttle program overall? Can an exmption be made for this application? How subject are we to unnecessarily restrictive environmental regulations, and what is the driving force behind this seemingly illogical chain of events?

Posted by Bob at July 28, 2005 10:03 PM

Ken is right, you do not fly the Orbiter, you fly it's computer. No computer, it's an even bigger rock.

What you are thinking of is re-entry. From the time the OMS Pods do the retro burn through what you might think of re-entry down to sub-hypersonic speed at around 60,000 some feet, the vehicle is flown by the computer in automatic mode under the observation of the fight crew. The pilot (ie mission commander) takes control while the ship is still supersonic and manually lands it...think of if as fly by wire, which actually it is.

The Orbiter has never "landed" under automatic control. "By landed" I mean from supersonic to wheels stop. It is capable of doing so.

The Russian Braun flew it's mission in total automatic mode.

By the way, formally a Shuttle consists of an Orbiter, an External Fuel Tank, and two solid rocket boosters. The part the reaches orbit and returns is the Orbiter, although Orbiter and Shuttle tend to used interchangeably.

Tank form shedding and dropping the occassional tile has been going on since the beginning. The shedding problem became somewhat worse with the change to the CFC-less bonding material.

What happened to the Columbia was the odds catching up. The reason it probably looks so bad now is that no one has ever looked in such detail before. However I do hold JSC responsible for Columbia because they knew of the shedding and kept explaining it away. I had a manager tell me that they knew of the impact and felt it was no big thing. Happens all the time he said.

And while I am at it, Challenger went down because of a burn thru in the SRB. (Some)Astronauts claimed they did not know about it. Told congress. They had been watching it. STS-9 had the worst problem of the lot until up at that time. When the extent problem with STS-9's SRB's became known STS-10 (Columbia) was sitting on the pad to fly the first Spacelab flight. The mission commander forced the Shuttle to be rolled back to the VAB and had the vehicle de-stacked, and the SRB's torn down and re-inspected, as was his right in my opinion.

After Challenger went down my feeling was that when the next one went down it would be by a bolt from the blue. I amke the same prediction for the next crash...assuming they ever fly again, which I would not bet a plug nickel on.

My money is on guys like Burt Rutan and Richard Branson. It will take longer, but they'll get 'er done.

Fuel can only be added to the OHMS Pods and the Foward Reaction Control system. All things being equal there is no need to do such a thing. as she carries all the fuel need to do the whole mission. The propellents are storable (subject to uncontrolled freezing and boil off, which would happend if the Orbiter is abandonded). To refuel those system on orbit would be well neigh physically impossible because of the hardware requirements to do so in zero-g.

Not saying impossible, say well-neigh

Posted by Michael at July 28, 2005 10:12 PM

Sorry....I was proof reading and accidently hit post rather than preview before I was done.

:-(((

Posted by Michael at July 28, 2005 10:19 PM

As I surf through reports, I'm seeing variations on whether the CFC is part of the application process or in the actual foam itself. Hmm, a dumb layman's sense would say that Freon-based foam would react to a cold-layer situation better.

OK that does it, Bring back the Freon foam!

Posted by Bob at July 28, 2005 11:04 PM

I saw the non-CFC foam in action in missile defense tests at White Sands in 1998, just after the switch on the External Fuel Tank too.

Our ballistic missiles were encapsulated in half-cylinder foam pieces while they are sitting to be launched (commonly overnight or a few days). When the missile rises during lift-off, cables pull of the foam. The foam whole -- they are just tugged by the cables on the ground, so they fall off. This is how we have done it for 40 years.

On the very next launch in 1998 with the new CFC-less foam, instead of the cables pulling off the foam, some of the foam pieces broke, and portions remained on the missile as it rose. The negative for us was that the foam introduced unforseen aerodynamic effects as the missile accelerated, and instigated attitude changes. I.e., had it not been for our roll and attitude thrusters compensating, it could have started a some serious roll or even a tumble. Eventually the pieces flew off as the missile achived higher speeds (and a sigh of relieve was heard in the room).

As an engineer, I have NO PROBLEM designing solutions for CFC-free materials. But that is for NEW DESIGNS! But we are talking about an EXISTING DESIGN -- purposely created and tested with a material to a specific set of mitigated risks. Simple engineering principles -- you NEVER, EVER introduce a material or other UNKNOWN QUANTITY mid-production that could greatly and adversely reduce the mititgated risks in a design.

Simply put, testing shows that not only is the reduced tensile strength of the CFC-less materials causing 11x as many breaks -- but more importantly -- prior to their use, there had NEVER been a cut anywhere close to 75% deep in a tile! And with the CFC-less materials, there were DOZENS!

With the CFC foam, Orbiter tile replacement averaged 40/flight, pretty much all due to heat. After replacement, over 110/flight, many very deep, many clearly due to impacts.

Now I never worked on any physical component of the Shuttle Transport System (STS) while I was out at NASA a few years ago. I worked on the system no one likes to talk about (i.e., I worked on the "FTS" for the USAF 45th Space Wing Eastern Range Safety). But many engineers who had been around NASA a long time said they would not fly on the STS themselves.

And one of the overriding reasons was mid-design changes without evaluating impact.

Posted by Bryan J. Smith at July 29, 2005 09:54 PM

BTW, if you didn't see what I was implying, what scares me to death is not that we're using CFC-less foam on STS.
What scares me to death is that we might be using this stuff on our military arsenal too!
Especially if CFC foams have been changed out for CFC-less foam on strategic, ballistic missiles.

Posted by Bryan J. Smith at July 29, 2005 09:57 PM

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