Comments on: Space Safety http://www.transterrestrial.com/?p=23342 Biting Commentary about Infinity...and Beyond! Thu, 09 Sep 2010 00:29:48 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Dennis Wingo http://www.transterrestrial.com/?p=23342&cpage=1#comment-90157 Dennis Wingo Thu, 03 Dec 2009 16:37:50 +0000 http://www.transterrestrial.com/?p=23342#comment-90157 <em>A mutual friend put it well: Joe Fragola is the Michael Mann of human spaceflight safety data.</em> Bumper Sticker on Fragola's car: (Will Adjust Data For Food). Lying to Augustine was just a bonus! A mutual friend put it well: Joe Fragola is the Michael Mann of human spaceflight safety data.

Bumper Sticker on Fragola’s car: (Will Adjust Data For Food). Lying to Augustine was just a bonus!

]]> By: Rod http://www.transterrestrial.com/?p=23342&cpage=1#comment-90009 Rod Wed, 02 Dec 2009 23:03:20 +0000 http://www.transterrestrial.com/?p=23342#comment-90009 Rand, I would like to add: a unitary srm with a no failures over many flights versus a large five segment solid with no history. Which would you chose as safe versus risky? Rand,

I would like to add: a unitary srm with a no failures over many flights versus a large five segment solid with no history. Which would you chose as safe versus risky?

]]> By: Rand Simberg http://www.transterrestrial.com/?p=23342&cpage=1#comment-89990 Rand Simberg Wed, 02 Dec 2009 21:21:45 +0000 http://www.transterrestrial.com/?p=23342#comment-89990 I think I can guess who that mutual friend is, but I won't out him or her. I think I can guess who that mutual friend is, but I won’t out him or her.

]]> By: Jim Muncy http://www.transterrestrial.com/?p=23342&cpage=1#comment-89984 Jim Muncy Wed, 02 Dec 2009 20:59:25 +0000 http://www.transterrestrial.com/?p=23342#comment-89984 Rand, I was at the T&I hearing this morning and then went over to this Show Trial of commercial crew. A mutual friend put it well: Joe Fragola is the Michael Mann of human spaceflight safety data. - Jim Rand,

I was at the T&I hearing this morning and then went over to this Show Trial of commercial crew.

A mutual friend put it well: Joe Fragola is the Michael Mann of human spaceflight safety data.

– Jim

]]> By: Karl Hallowell http://www.transterrestrial.com/?p=23342&cpage=1#comment-89941 Karl Hallowell Wed, 02 Dec 2009 17:35:30 +0000 http://www.transterrestrial.com/?p=23342#comment-89941 I see two big problems with the claim that Ares I can be designed with a 1 in 2800 failure rate. First, the SRMs have a historical failure rate of somewhere around 1 in 200 to 1 in 400. Second, the flight rate is too low to insure the above failure rate. For example, a number of changes were made to the remaining Shuttles after the Columbia accident. How do we know that we didn't introduce a failure mode with those changes? The answer is that we haven't yet had another accident (or close call for that matter) in 16 launches. Even if we had introduced a 1 in 10 failure mode, we'd still have a roughly 19% chance of making it this far without accident. The point here is that a high flight rate finds these problems pretty fast. There are more flights per significant change. I see two big problems with the claim that Ares I can be designed with a 1 in 2800 failure rate. First, the SRMs have a historical failure rate of somewhere around 1 in 200 to 1 in 400. Second, the flight rate is too low to insure the above failure rate.

For example, a number of changes were made to the remaining Shuttles after the Columbia accident. How do we know that we didn’t introduce a failure mode with those changes? The answer is that we haven’t yet had another accident (or close call for that matter) in 16 launches. Even if we had introduced a 1 in 10 failure mode, we’d still have a roughly 19% chance of making it this far without accident.

The point here is that a high flight rate finds these problems pretty fast. There are more flights per significant change.

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