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Early Abort of Ares I Rocket Would Kill Crew
FleaPlus writes "From studying past solid rocket launch failures, the 45th Space Wing of the US Air Force has concluded that an early abort (up to a minute after launch) of NASA Marshall Flight Center's Ares I rocket would have a ~100% chance of killing all crew (report summary and link), even if the launch escape system were activated. This would be due to the capsule being surrounded until ground impact by a 3-mile-wide cloud of burning solid propellant fragments, which would melt the parachute. NASA management has stated that their computer models predict a safe outcome. The Air Force has also been hesitant to give launch range approval to the predecessor Ares I-X suborbital rocket, since its solid rocket vibrations are violent enough to disable both its steering and self-destruct module, endangering people on the ground."
I worked at Marshall Space Flight Center -- the facility where the Ares is being developed -- for a while as part of an undergrad summer research project. While it may not be polite to say such things, AC's criticism of NASA's affirmative action policies is spot on.
My boss and his officemate were both affirmative action hires. My boss couldn't remember his computer password and called IT every time he crashed WinNT and needed to reboot. His officemate just put his on a stickynote on his monitor. When he got a new computer he had to get me (an undergrad) to make him a desktop shortcut to Solitaire. I have no idea what that guy did other than order office supplies.
My boss often skipped work to play golf, leaving me in charge of the lab. I wound up growing samples in a gas deposition chamber and giving them to him to catalog and characterize. At one point I asked him how the characterization was going, and he said that the Raman spectroscopy lab was buried under a backlog of debris from Columbia (which was earlier that year). At the end of the summer I had a chat with *his* boss, who told me that there was no such backlog... and then we found all the samples I had painstakingly grown and labelled lying jumbled in the bottom of a drawer of his.
While it makes me sad to say it, I've seen Marshall Space Flight Center incompetence with my own eyes. I'm from Huntsville, the city where MSFC is located. When I was growing up Real Science got done there -- my high school English teacher is the guy who built the Lunar Rover. But it's gone downhill.
I also know the guy who's in charge of systems integration for the Ares project. He's a young-earth creationist. I have little faith in the engineering acumen of anyone who can accomplish such a massive feat of ignoring experimental evidence.
How much risk is acceptable? Is the Air Force suggesting that space exloration should be 0% risk, or less?
If so, then we should probably ground all aircraft, scrap all automobiles - you get the idea.
Let's face it. Sitting on top of tons of explosive, and lighting them off, is going to be risky. Minimize the risk, yeah, but there will always BE RISK. It doesn't matter what kind of engine you are using, or what kind of fuel it is using. A crash within the first minute of flight is often quite deadly in aviation simply because the pilot has so few options for ditching or bailing out. The same will always be true of spaceflight.
If we want 0% risk, we had better get started on that space elevator. Of course, there may be some hidden risk at some point in that ascent - but at least we won't be blowing it up to use it.
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
The survival rate for exploding Soyuz rockets is 100%. It happened once in 1975, and again in 1983. Both times, the crew escaped without major injury. The Russian/Soviet space program has never had a launch failure that resulted in fatalities to crew aboard the ship.
The 1983 incident occurred as the rocket exploded while on the pad, and threw the capsule 6,500 feet into the air, subjecting the cosmonauts to approximately 17g of acceleration. According to popular legend, the cosmonauts destroyed the capsule's voice recorder due to the lengthy string of profanity that it captured during the incident.
-- If you try to fail and succeed, which have you done? - Uli's moose
Fortunately it seems like this is a problem that *could be corrected* fairly easily -- with, say, a propulsion mechanism on the escape capsule, just enough to give enough delta-V that it would clear the debris cloud in time to deploy the parachutes.
From what I understand, the Orion capsule's launch escape system already has a jettison motor, but it's not enough to take it out of range of the flaming debris. Increasing the range of the motor isn't an option, because the capsule is already too heavy for the Ares I and they can't add even more weight to it.
Even though rockets like DIRECT's and the Ares V would have the "field of flaming solid rocket propellant debris" problem, my impression is that they have a big enough margin that you'd be able to have a launch escape system that could escape the debris cloud.
Oddly enough that regime was so fond of paperwork that there were weird documents along the lines of "order to destroy all records of the mass graves at lat X long Y containing Z bodies from the incident on DATE" with all the correct numbers filled in. People were so careful to cover their arses that everything was written down (even attempts to duplicate things that had been ordered destroyed) and is now a goldmine for historians. However there is still the garbage in garbage out problem if the information was wrong in the first place.
Nitpick: The Challenger SRBs were fine. The external tank failed.
The SRBs leaked a bit of fire through the O-ring, and that fire meant that one of the SRBs cut itself away from the external tank - the attachment at the bottom of the tank failed, the one at the top didn't, and that was enough to plow the nose of the SRB into the tip of the external tank.
*boom*
The external tank tore itself apart from the aerodynamic stresses, leading to the big white plume of water vapor. The shuttle was torn apart shortly thereafter from similar aerodynamic stresses.
Both SRBs - even the one with fire belching out of the lower O-ring - can be seen in video of the disaster as flying onwards, well away from the conflagration, relatively unscathed. They were eventually blown up by range control officers.
The root cause of the failure cascade was indeed a problem with the SRB, things did go to hell all of a sudden in a rather spectacular way, and it certainly sucked to be them.
But technically, the SRBs themselves didn't fail catastrophically. Anyone lucky (?) enough to have been riding along in the nose cone of the SRB along with the SRB parachutes (let's assume the presence of suitable breathing apparatus since it's probably not pressurized, the presence of sound/vibrationproofing, temperature control, and of course, a nice parachute for our intrepid stowaway) would have had pretty good odds compared to the Challenger crew... well, at least until range control blew up the SRBs.
Actually it does matter how the Challenger failed. It matters because the issue being discussed is whether or not sitting a crew on top of a SSB passes the safety standard that NASA is using. The GGP claimed the Challenger disaster was due to a SSB failure, and the GP corrected him.
If you read the GP again you'll see that he is pointing out that while SSBs have terrible failure modes, the probability of reaching those modes is lower. In any risk analysis it is important to quantify the probability of a complete failure, as well as the impact.
Give than an SSB is essentially a giant firework, which once lit the only thing to do is either a) retreat to a safe distance (ground staff) or b) pray (crew), it is saying something that the overall safety could be higher than the shuttle. But the shuttle takes the same dangerous SSBs and adds millions of complex parts with non-zero probabilities of failure.
While you have a point about redesigning the rocket until the escape system does work, and for a commercial transport system this would be essential, you seem to be missing something vital. Launch vehicles like this are at the limit of our current technology and engineering skills. We may have to settle for making them work at all, rather than extra niceties such as safety. Given the huge amounts of energy required to reach space, and that currently the only options that we have are detonating vast quantities of explosives slowly... there is a limit to how safe we can make this.
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