Let's try this again;/. messed up my login my first attempt.
We were discussing this last week on a technical e-mail list. Agreement was pretty much unanimous - with lots more evidence than I mentioned here - that this is someone blowing a valid but incremental development out of proportion.
When I was working on my BSCE in the mid-Seventies I had a course on concrete additives. Pozzolanic ash was definitely mentioned. I have also seen this mentioned many other places since then, including the fact that some of the Roman concrete mixes would cure under water. So, no, this isn't some revolutionary new discovery. Those claiming so are either ignorant of previous art - and that's *recent* previous art - or are deliberately trying to build up their own claims.
"It'd be the easiest way to establish a permanent moon base..."
Because if the landing area isn't flat before you get there, it will be afterwards.:-^)
Actually, I'm a long time Orion fan, and am still looking forward to it being revived when we develop fusion explosives without fission primaries.
The original Orion team got the environmental impact down to an estimated one additional human death per launch (from cancer due to fallout) and felt they could do better with more time and money. With modern weapon design software, optimizing for launch purposes rather than destruction, the launch impact could be greatly reduced even over what they believed possible.
Would you accept Orion launches if they only killed one person per ten? Twenty? Hundred? The design of nuclear explosives isn't my field so I don't know exactly how low we could go right now. Neither can I judge how many launches per death is the justification limit. But I do know that _every launch to space_ has a distinct environmental impact. If an Orion launch which puts more mass than an entire Space Transportation System stack at liftoff into LEO has a lower environmental impact than the aluminum and other materials the solid rocket boosters disperse during an STS launch, would you accept it then?
I am not being snarky, here. These are legitimate concerns, and the cost to benefit balance a complicated matter. So is the public perception of these concerns. People have a distressing tendency to be more accepting of risk from non-nuclear sources than nuclear sources, through ignorance.
The Board states in the report that they asked NASA what could have done if the seriousness of the damage had been confirmed. NASA responded by staging a real-time simulation, assuming the discovery had been made late in the mission. They worked two solutions in parallel. One had a repair-on-orbit solution using materials on
board _Columbia_. It included jettisoning most of the cargo and using a reentry which put a lower heat load on the damaged area.
The other had _Atlantis_ making a rendezvous with a crew of four and docking equipment. With no major countdown holds and the _Columbia_ crew taking it easy, this could have been done before the last of their carbon dioxide absorbing cannisters was used up.
The second alternative was by far the preferred, since they couldn't be sure the repair would hold. But it would probably have been done anyway, in case _Atlantis_ was late.
Following crew recovery, the empty _Columbia_ would have been put into a reentry into the ocean, or boosted to a higher orbit for later repair.
Stickmaker
>Because you can be DANM SURE they'd never screw up >again. Instead, there's a whole NEW group of >managers to F**K up for the first time all over >again!
Not in this case.
The report notes that in interviews with the investigation board many of the managers defended their decisions, stating that the engineers never made it clear that the Orbiter and its crew were in danger. Turns out they were looking for specific words and phrases, which the engineers never used. Therefore, no matter what they said, it simply didn't meet the criteria the managers had for ruling the problem significant.
In minutes of the first meeting on the matter, engineers stated that a foam insulation strike had damaged the tiles, perhaps enough for a burn through, which could possibly result in loss of the vehicle. The managers stated that the matter wasn't urgent, and they could check the damage after _Columbia_ landed. The managers had looked up "insulation foam strike" in their manuals and seen that it was a Repair Turnaround issue, not a Flight Safety issue, and dismissed the engineers' statements.
In a later meeting one engineer stated that getting more data was _mandatory_. One of the managers asked him by what criteria was he ruling it mandatory. The engineer explained the situation as best he understood it, emphasizing the danger. The manager dismissed his concerns. Turns out there was a list of words and phrases which could be used to make something mandatory, and the engineer hadn't used any of them.
These managers weren't managing, _they were following if-then flowcharts_! They had a set of approved procedures they followed, and because this incident was unlike any before it (the foam insulation chunk was orders of magnitude larger than any previously confirmed) they kept getting the wrong answers from their procedures.
Stickmaker
Slashdot Mirror
Let's try this again; /. messed up my login my first attempt.
We were discussing this last week on a technical e-mail list. Agreement was pretty much unanimous - with lots more evidence than I mentioned here - that this is someone blowing a valid but incremental development out of proportion.
When I was working on my BSCE in the mid-Seventies I had a course on concrete additives. Pozzolanic ash was definitely mentioned. I have also seen this mentioned many other places since then, including the fact that some of the Roman concrete mixes would cure under water. So, no, this isn't some revolutionary new discovery. Those claiming so are either ignorant of previous art - and that's *recent* previous art - or are deliberately trying to build up their own claims.
"It'd be the easiest way to establish a permanent moon base..." Because if the landing area isn't flat before you get there, it will be afterwards. :-^)
Actually, I'm a long time Orion fan, and am still looking forward to it being revived when we develop fusion explosives without fission primaries.
The original Orion team got the environmental impact down to an estimated one additional human death per launch (from cancer due to fallout) and felt they could do better with more time and money. With modern weapon design software, optimizing for launch purposes rather than destruction, the launch impact could be greatly reduced even over what they believed possible.
Would you accept Orion launches if they only killed one person per ten? Twenty? Hundred? The design of nuclear explosives isn't my field so I don't know exactly how low we could go right now. Neither can I judge how many launches per death is the justification limit. But I do know that _every launch to space_ has a distinct environmental impact. If an Orion launch which puts more mass than an entire Space Transportation System stack at liftoff into LEO has a lower environmental impact than the aluminum and other materials the solid rocket boosters disperse during an STS launch, would you accept it then?
I am not being snarky, here. These are legitimate concerns, and the cost to benefit balance a complicated matter. So is the public perception of these concerns. People have a distressing tendency to be more accepting of risk from non-nuclear sources than nuclear sources, through ignorance.
The Board states in the report that they asked NASA what could have done if the seriousness of the damage had been confirmed. NASA responded by staging a real-time simulation, assuming the discovery had been made late in the mission. They worked two solutions in parallel. One had a repair-on-orbit solution using materials on board _Columbia_. It included jettisoning most of the cargo and using a reentry which put a lower heat load on the damaged area. The other had _Atlantis_ making a rendezvous with a crew of four and docking equipment. With no major countdown holds and the _Columbia_ crew taking it easy, this could have been done before the last of their carbon dioxide absorbing cannisters was used up. The second alternative was by far the preferred, since they couldn't be sure the repair would hold. But it would probably have been done anyway, in case _Atlantis_ was late. Following crew recovery, the empty _Columbia_ would have been put into a reentry into the ocean, or boosted to a higher orbit for later repair. Stickmaker
>Because you can be DANM SURE they'd never screw up >again. Instead, there's a whole NEW group of >managers to F**K up for the first time all over >again! Not in this case. The report notes that in interviews with the investigation board many of the managers defended their decisions, stating that the engineers never made it clear that the Orbiter and its crew were in danger. Turns out they were looking for specific words and phrases, which the engineers never used. Therefore, no matter what they said, it simply didn't meet the criteria the managers had for ruling the problem significant. In minutes of the first meeting on the matter, engineers stated that a foam insulation strike had damaged the tiles, perhaps enough for a burn through, which could possibly result in loss of the vehicle. The managers stated that the matter wasn't urgent, and they could check the damage after _Columbia_ landed. The managers had looked up "insulation foam strike" in their manuals and seen that it was a Repair Turnaround issue, not a Flight Safety issue, and dismissed the engineers' statements. In a later meeting one engineer stated that getting more data was _mandatory_. One of the managers asked him by what criteria was he ruling it mandatory. The engineer explained the situation as best he understood it, emphasizing the danger. The manager dismissed his concerns. Turns out there was a list of words and phrases which could be used to make something mandatory, and the engineer hadn't used any of them. These managers weren't managing, _they were following if-then flowcharts_! They had a set of approved procedures they followed, and because this incident was unlike any before it (the foam insulation chunk was orders of magnitude larger than any previously confirmed) they kept getting the wrong answers from their procedures. Stickmaker