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SpaceX is no stranger to delays. The private space firm headed by Elon Musk has pushed back is launch schedule several times in the last few years after rockets have been lost. Now, the Government Accountability Office (GAO) says there may be an issue with the Falcon 9 rocket that delays the expected launch of the first manned mission in 2018.
The report from the GAO (just a preliminary release for now) cites issues with the turboblades used in Falcon 9 rockets. These are the components that move fuel from the tanks to engines. The blades apparently have a tendency to develop cracks, which could cause catastrophic failure if they develop or worsen during a launch.
According to NASA acting administrator Robert Lightfoot (who also has an amazing name) says the agency and SpaceX have been aware of the issue for months (or possibly years). NASA expressed concern to SpaceX that the turboblade cracks presented too great a risk to launch manned missions. Cracks have been found in the turboblades as recently as September 2016.
SpaceX says it has been conducting extensive testing on the Falcon 9 rocket and believes it to be safe. It has made changes to the design of the turboblades in an effort to mitigate the cracking issues. Although, the company may still undertake a full redesign of the blades depending on the upcoming GAO report. If that happens, the manned launch will almost certainly be delayed.
Source:
https://www.extremetech.com/extreme/243883-problems-falcon-9-design-delay-manned-missions
(Score: 2) by choose another one on Monday February 06 2017, @08:31PM
> Sure the tank only self destructs 1 in 50 flights and that maybe makes economic sense when launching unmanned GPS satellites, but it doesn't make sense for a manned launcher.
What number makes sense for a manned launcher? 1 in 65 fatality rate perhaps? 1.5% of flights?
Would a 1 in 50 flight fail rate with a launch abort be better that 1.5% with no abort option? Which would you rather ride on?
The shuttle took the baked-in-from-the-start approach to man rating and chose to use SRBs (which at the time had around 1 in 50 fail rate), chose segmented SRBs vs. single piece SRBs (why have a joint that can fail if you can build in one piece?), chose to use manned vehicle heat shielding that was fragile and then put the manned vehicle not on the top of the stack (like every manned rocket before or since, out of harms way as much as possible), but instead put it _behind_ most of the main tank, which was covered in an insulation jacket that was sprayed on rather than manufactured and was known to shed fragments.
The shuttle had multiple intrinsic safety failures _despite_ having baked in man-rating from the start, and despite this had no launch abort / escape option, Falcon9 will also probably (inevitably?) have multiple intrinsic safety failures, but it will have have a launch abort / escape option, and the kinks will be ironed out first with unmanned flights.
The COPV tanks are safe as long as the struts are manufactured to spec and the launch temps are "correct", except no one really knows what "correct" is. Sounds bad - except it is exactly the same as the O-Rings on the shuttle, not intrinsically safe, vehicle could have been designed without it, safe if used at the right temps but no one knew what those were in advance. The big difference is that the O-Rings were a man-rated-baked-in design and were tested at new launch temps with a crew on board, SpaceX only tested new launch temps with a satellite on board.
Which is the best approach? Only time will tell, but time has not been kind to NASA's shuttle approach. NASA's approach also carried a cost premium of 10x (maybe 100x if SpaceX does get reusable). Was it worth it?
(Score: 2) by VLM on Monday February 06 2017, @09:21PM
The shuttle had multiple intrinsic safety failures _despite_ having baked in man-rating from the start
They baked in political deals from the start. Hard to have a SRB failure if you don't have SRB although you don't get the Utah vote without SRBs so we gotta have SRBs even if they kill people.
The insulation deaths were the same way. The ET spray on foam is environmentally negligible but they couldn't use the good stuff because it looks bad to be anti-environment on TV, so instead they killed a bunch of people by using stuff that is more environmental but falls off and cracks heatshields. Sure we littered parts of the shuttle and parts of the astronauts all over Texas but thank god we didn't use environmentally unfriendly insulation, that's what really matters in a human-life space program, not mere human lives.
You have to balance SpaceX is doing questionable things vs NASA just plain old sucks.