I wasn’t planning on doing any more blogging today, but I had a serious “what the hud!” moment earlier today, and thought it worth bringing attention to it. This is a presentation that was given by NASA back on July 2nd, and linked to by “anonymous.space” over in a comments section in Space Politics. Anonymous.space brought attention to three rather troubling slides: pages 26, and 62-65.
Basically, unless this source is bogus, or I’m completely misreading things, it’s saying that even NASA admits that their odds of losing a crew or a mission using the Constellation architecture are far worse then they had originally claimed. In fact, at least for ISS missions, we’re talking almost an order of magnitude worse. For ISS, they’re claiming a LOC (probability of losing the crew on any given flight) of 1 in 231, with a LOM (loss of mission) of 1 in 19! If I’m reading this right, that means they expect right now that about 5% of missions to the space station will end up not making it to the station. For lunar missions, the LOC number is 1 in 170, and the LOM number is 1 in 9! That means of every multi-billion dollar mission, they’ve got an almost 11% chance of it being a failure. While some of these numbers have been improving, others have been getting worse.
To put this in perspective, the statistical reliability of most ELVs is rated at about 95-98%. One of the big selling points of Ares-1 was that it was going to be so much safer than any other vehicle that’s ever flown. The claim IIRC from ESAS was that the odds of losing a mission were going to be 1 in 460, which is about 9x more reliable than any other vehicle that’s ever flown. Not bad for a team that’s hasn’t designed, built, and operated a new launch in over 25 years. The Loss of Crew probability was supposed to be 1 in 2021 (both of these numbers can be found on the NASA ESAS Report website in chapter 6 on page 382). Now, I’ve made fun of them quoting four significant figures on reliability for something that hasn’t flown yet (though I apparently misremembered the numbers–I thought it was 1 in 2106…silly me).
In other words, it appears that NASA is admitting that the Ares-1 is not going to be any safer than an EELV/EELV derived launcher would’ve been, and in fact may be less reliable.
Am I misreading something? If not, why hasn’t anybody (other than anonymous.space) been discussing this? While it’s true, things may get better with time, but so far the numbers have been getting consistently worse. And they’re currently over an order of magnitude worse than what “we” were “sold” on. What the hud?!?
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