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Author
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Topic: "The worst glove damage we have seen in the history of going EVA"
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Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 04-13-2007 03:36 PM
   
NASASpaceflight.com published an article yesterday about the damage sustained to Robert "Beamer" Curbeam's right glove during the STS-116 mission spacewalks. As I was scheduled to interview NASA's EVA Office Manager Stephen Doering today on an unrelated topic, I ended our call by asking if he would describe the "hole" and the steps being taken to understand it. Here is his reply: quote:
We have seen de-lamination of the RTV — the rubberized coating on the palm of the glove — we have seen that before. It is not a sharp edge protection. It is for grip and for thermal. And we've seen when you do very hand intensive activities, like what Beamer was doing on his flight with a lot of the electrical connectors, that was expected. The "hole", I'll call it, in the vectran weave, which is the actual palm of the micrometeroid garment [TMG] underneath the RTV, was a surprise because we didn't see it until after we got the glove back. It was not reported in-flight. When we looked at it, when it was back at USA [United Space Alliance], they pulled the glove out of its shipping container and the tech saw that and immediately called us and we — it was a Friday afternoon — we went over there and took a look at it. We initially thought just in looking at it that, well we must have had the RTV de-lamination happen early on, and then Beamer went out and did a bunch of electrical connectors after that and this was a wear-through due to the electrical connectors. But we weren't completely convinced so we sent that glove back to ILC to have them take a look at it. They put it under the microscope and you can tell that the fibers were sliced because the end of the fibers were even, rather than frayed like a wear. So at that point we knew we had either a sharp edge or a pinch point, somewhere that was unexpected that we needed to go investigate. And so we've been doing that. We'll probably not having a smoking gun, just because we've narrowed it down to it happened sometime on EVA 3, based on the video analysis. He lost the RTV earlier on EVA 2 and then at the end of EVA 3 you can see on the video the hole in the glove. The TMG is very hard to get through, to cut through that, and you're still two layers away from the pressure bladder. So, while it is a hole — and we're taking it very seriously because it is a large enough hole in that piece of the cloth that would have constituted an emergency had it also been of the same size in the bladder — you've got to remember, there's a lot of stuff there and the likelihood of getting to the bladder in this particular case — while we don't have the ability to guarantee it wouldn't happen — the likelihood of it getting down that far is pretty slim, yet its still a non-zero number. I'll characterize this as the worst glove damage we have seen in the history of going EVA for the U.S. program. But the bladder restraint and the bladder itself showed no markings whatsoever. So, the question we ask ourselves is did we get lucky or was the cut in a way that we wouldn't have gotten in. We suspect it was a pinch point in the linkage of the electrical connectors and we are in the process of trying to duplicate that.
Doering also answered what would have happened had there been a pressure leak: quote:
[Curbeam] would have gotten a high-flow message or a pressure-drop message on the caution and warning system on the suit and it would have sent him back to the airlock. Depending on the magnitude of the leak, it would have been either — we have three ways, three different criteria of getting back to the airlock. We have a terminate EVA or an abort EVA. Terminate EVA means you clean things up, if the leak is enough that you have time, therefore, clean-up the systems, safe the work-site that you're working on and make your way back to the airlock and do a nominal repress. Abort EVA is to get back to the airlock, get hooked up to the umbilical as quickly as possible, and then the third part of that is whether you do a normal repress or an emergency repress. And there's enough gas in the secondary oxygen pack for 30 minutes.
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John Youskauskas
Member Posts: 126
From:
Registered: Jan 2004
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posted 04-16-2007 05:05 PM
Great reporting Robert...thanks! I think if I got ANY message concerning suit pressure, I'd take that "Abort EVA" option with an extra "Right Now!" added. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 05-24-2007 08:02 AM
An update from the Houston Chronicle:
Cut in spacewalker's glove prompts concern at NASA quote:
NASA said Wednesday it plans more rigorous inspections of the bulky gloves worn by spacewalking shuttle astronauts after it discovered a three-quarter-inch slice in the protective garment worn by one of the fliers assigned to December's assembly mission to the international space station.
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dtemple
Member Posts: 729
From: Longview, Texas, USA
Registered: Apr 2000
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posted 06-02-2007 11:35 AM
NASA management seems quite comfortable with a hole in a spacesuit glove. "We've seen that before" sounds familiar. I guess when they finally kill an astronaut during EVA, NASA managers will get much more serious about the problem. This makes me wonder what other problems NASA has seen in past missions that are being treated the same way. They got serious about O-rings after the Challenger disintegrated and they got serious about external tank foam loss after the Columbia disintegrated even though foam loss had happened very early in the shuttle program. Secondary O-rings had always held and the odds of a foam strike causing catastrophic damage to the thermal protection system seemed remote so why fix these problems? That logic did not stop fourteen astronauts from being killed. I guess dead astronauts are required for each serious problem to get a fix. After the Apollo 1 fire, NASA looked at the entire spacecraft (CSM and LM) and even launch pad procedures in terms of what they could make better - not just protection for wiring in the CM. The entire astronaut corp ought to refuse to fly until management's attitude changes. Of course that will not happen. NASA management failures have killed fourteen astronauts since 1986 - not technical failures - not pushing the unknown. This same group of people is about to send astronauts to the moon where the risks are much greater. The hostile environment of space is waiting for the next victims of NASA management. I guess the only good thing that can be said about that is in the future NASA managers will kill only up to four astronauts at a time instead of seven. Yes, I know that sounds harsh but re-read the original article that started this thread or just read these excerpts of it here: quote:
"We have seen de-lamination of the RTV — the rubberized coating on the palm of the glove — we have seen that before. It is not a sharp edge protection. It is for grip and for thermal. And we've seen when you do very hand intensive activities, like what Beamer was doing on his flight with a lot of the electrical connectors, that was expected..."...you've got to remember, there's a lot of stuff there and the likelihood of getting to the bladder in this particular case — while we don't have the ability to guarantee it wouldn't happen — the likelihood of it getting down that far is pretty slim, yet its still a non-zero number..." "So, the question we ask ourselves is did we get lucky..."
I say NASA is lucky to have even three orbiters in service. Maybe the next moonwalkers should carry light-weight headstones in their PPKs with an inscription reading, "Here lies ____ killed by a problem NASA had seen before." |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-02-2007 11:53 AM
It is not like NASA is just sitting on its hands (no pun intended) with regards to this concern. If you read the Houston Chronicle article linked above: quote:
As a result of its findings, NASA will now require astronauts to inspect their gloves after every major assembly task during a spacewalk, or about once an hour. If they find a cut greater than a quarter-inch in the glove's outer fabric, the spacewalk will be called to a halt, said Doering.
Meanwhile, NASA is designing the requirements for the next generation Orion spacesuit, taking into consideration what it has learned from this and other experiences. Spacesuits, and in particular spacesuit gloves, have to balance maintaining dexterity while protecting the wearer. There is no such thing as an indestructible material that allows for both. The best NASA can do is to watch for problems (which they are doing), study them when they occur (which they have done) and recommend changes to procedure as more is learned (as they have done). And let's keep in mind, "the worst glove damage we have seen," as categorized by Doering was never a risk to Robert Curbeam, who was wearing the glove at the time. So the design of the glove, even with the damage, seems to have been proven as effective. |
dtemple
Member Posts: 729
From: Longview, Texas, USA
Registered: Apr 2000
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posted 06-03-2007 03:16 PM
quote:
And let's keep in mind, "the worst glove damage we have seen," as categorized by Doering was never a risk to Robert Curbeam, who was wearing the glove at the time. So the design of the glove, even with the damage, seems to have been proven as effective.
You may be right, Robert. However, the o-rings never burned through until catastrophic failure transpired. Remember there was "the worst" situation ever seen that didn't seem to worry NASA managers too much either prior to the loss of Challenger. If the shuttles had never been launched in cold weather, then the o-ring design would probably have been sufficient though just barely. However, there was that one additional variable that entered into the picture on launch day that made the design totally fail. What will happen if an EVA must be aborted while tiles are being repaired? EVA suits simply should not be allowed to get holes in them even if it doesn't seem to be an obvious threat to the crewmember wearing it. It's the "we've seen this before" attitude that seems similar to the past situations that led to fourteen dead astronauts. Why wasn't this situation addressed during the long shuttle stand-down after the loss of Columbia? Maybe NASA has control of the situation, but based simply on what I am reading it doesn't really seem that way. I hope my concern is unjustified. If, however, what I think I am sensing is real, then what will happen to lunar exploration if astronauts are killed early in the program due simply to another management failure? Eventually, an astronaut will die on the moon. Spaceflight can never be risk-free. But negligence, is never an acceptable reason. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-03-2007 03:50 PM
In this specific case, I think you are misreading the situation. To compare the glove damage experienced during STS-116 to o-ring blow-by is like comparing a crack in a sidewalk to a crack in the Hoover Dam. If the integrity of the sidewalk is compromised, pedestrians are redirected; if the integrity of the dam fails, flooding ensues.Even if NASA hadn't changed its procedures (as they now have done) Doering explained that the worst case scenario in regards to Beamer's glove would have been an early end to the EVA. The suit's own caution and warning system would increase the flow of air to compensate for a leak, allowing Beamer the time to get back to the airlock. That's why the C&W system exists. As I wrote earlier, there is no such thing as an indestructible spacesuit design that also allows for dexterity and movement. If you are going to accept that astronauts are needed for EVA operations, than you need to accept a level of risk. That's not poor management; that's reality. The losses of Challenger and Columbia were caused as a result of NASA deciding to ignore its own rules set forth for flight safety. No rules are being ignored by still using the EMU gloves; if anything, more rules have been added to further protect the astronauts. This is not a case of management ignoring the risks but rather understanding them and operating within their confines. | |
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