Hacker News new | past | comments | ask | show | jobs | submit login

So far, SpaceX has completed 23 launches of both its Falcon 1 & currently active Falcon 9 rocket: http://spacexstats.com/previous.php

They have had two failures: https://en.wikipedia.org/wiki/List_of_Falcon_9_and_Falcon_He...

Out of 25 launches is that a safe enough success rate?




The first failure was a secondary payload. The Falcon 9 had less spare fuel than expected because one of the first stage engines failed.[1] The primary (NASA) mission went fine. The secondary mission had a 95% chance of success, but NASA vetoed it.

The second failure was a second stage exploding. Had the payload been a crewed Dragon V2, those inside would have survived. Even without a launch escape system, the Dragon V1 was fine[2]:

> The Dragon CRS-7 capsule was ejected from the exploding launch vehicle and continued transmitting data until impact with the ocean. SpaceX officials stated that it could have been recovered if the parachutes deployed, however the software in the capsule did not include any provisions for parachute deployment in this situation.

Overall, it's a much safer design than the Shuttle. The crew vehicle is on top of the stack instead of along side it. If anything goes wrong, the capsule can GTFO and land with parachutes.

1. https://en.wikipedia.org/wiki/SpaceX_CRS-1

2. https://en.wikipedia.org/wiki/SpaceX_CRS-7


> however the software in the capsule did not include any provisions for parachute deployment in this situation.

That seems like a pretty significant oversight?


It wasn't an oversight. It was intentional. The Dragon v1 is designed solely for cargo. It has no launch escape system and its software does nothing while it's going up[1]:

> The software in this cargo version of Dragon (Dragon 1), Musk explained, is inert on ascent and was not programmed to release the parachute in the event of a failure. Software in the version of Dragon under development for taking people into space (Dragon 2 or Crew Dragon) is programmed to do just that.

While it sounds like simple thing, remote control of the 'chutes would add significant complexity and cost.

1. http://www.spacepolicyonline.com/news/failed-strut-likely-ca...


Also, you generally want as many systems "off" as you can manage during the flight. There's just less that can go wrong if there is less going on.


And remember to set your SCE to aux.


That was actually a very interesting read.

http://motherboard.vice.com/read/john-aaron-apollo-12-curios...


"But Bean, who was sitting in the right seat, just in front of the switch, remembered it from the sim the previous year."

I guess we can forgive Bean for frying the color TV camera, then.


I know what that is!!!!


No one expected Dragon to survive those conditions, so they never bothered adding that code. It's just a cargo ship, so it doesn't really matter.

After having learned in real world conditions that it can handle those sorts they figured, what the heck... might as well add it.

The crewed Dragon (Dragon 2) uses powered thrusters to push itself away from a failing rocket.


Water landings only work if you design for them which is a lot of extra weight. Catching the thing in the air is difficult because you get very little warning and they can land in a huge area.

Net result, failed launches are not really worth trying to recover unless it's people. Though, deploying parachutes may have marginally reduced the risks to a passing boat.


Dragon already lands on water, so there's no technical reason it couldn't do it after a launch vehicle failure, if the event was survivable. Now we know that such a scenario exists, but that was not obvious before.


My understanding is Dragon 1 does not float fully loaded. It can get 3,10 kg ISS used and dispose of 3,10 kg of waste, but only to recover ~2,500 kg. https://en.m.wikipedia.org/wiki/Dragon_(spacecraft)


Make that "3,310 kg ISS" not "3,10 kg"


I believe the difference between up and down cargo is because the trunk is dropped and burns up on entry, only the pressurized capsule itself lands.


> Though, deploying parachutes may have marginally reduced the risks to a passing boat.

Didn't it fall in the range safety exclusion zone, which ships were warned away from?


It wasn't an oversight - they launched the mission with the understanding that their parachute software wasn't ready and the risk was acceptable since it was uncrewed. I seem to remember reading that their parachute hardware was ready to go if absolutely necessary, but they wanted to make sure the software was locked down.


Not necessarily, if there was no reason to recover it

(I'm not sure if there was a reason or not)


Move fast and crash things!


Mercury was flown on Redstone rockets for suborbital flights and Atlas rockets for orbital flights.

Redstone had a success rate of 5/6. [1] Atlas had a success rate of 13/24. [2]

It was certainly a different time, but spaceflight has always been really risky. There has also always been more attention paid to human rated flights during the manufacturing & testing process. I also imagine SpaceX will not be doing first flights of new Falcon 9 variations with humans aboard.

That's not to say it is low risk, but 23/25 considering these are unmanned and largely R&D flights is not bad.

[1] https://en.wikipedia.org/wiki/Mercury-Redstone_Launch_Vehicl...

[2] https://en.wikipedia.org/wiki/SM-65_Atlas#Atlas-D_deployment


Well the D was the first operational and it did not have that failure rate that the A,B, and C, models had. I doubt NASA would have ever launched a version that didn't have a high nineties success rate.


That's flat out not true. Take a look at the list of Atlas D launched and look at the failures. The first time they strapped a Mercury capsule to an Atlas D is failed. There was an Atlas D failure in February 1962, and Scott Carpenter rode it for the first manned flight only 3 months later in May 1962.

The day before Walter Schirra launched there was an Atlas D failure.

Two months before Gordon Cooper launched there was an Atlas D failure.

What I don't know is how much they were pushing the limits on the other tests vs the manned flights, or how much more QA they were putting into the manned rockets, but it is certainly not the case that NASA only flew on rockets with high success rates at that time.

[1] https://en.wikipedia.org/wiki/List_of_Atlas_launches_(1960%E...

[2] https://en.wikipedia.org/wiki/List_of_Atlas_launches_(1957%E...


Saying "two failures" is awfully misleading. There was one catastrophic failure and one minor failure. In a hypothetical manned mission, the minor failure probably wouldn't have even prevented the mission from going forward, let alone endangered the crew.

The catastrophic failure is obviously a problem. However, for a manned mission, there is an abort system which is supposed to save the lives of the crew in an event like this. This is not like the Shuttle where if anything goes wrong on launch, everybody is doomed.

To state it more precisely, out of 25 launches, there has been one problem which wouldn't have been a threat, one catastrophic failure which would be survivable, and zero failures which would have killed anybody if they had been manned.


There were at least two catastrophic failures that everyone knows about: Challenger and Columbia.


We're talking about SpaceX here.


Looks like I've misread.


I dug up the number for Shuttle missions for comparison: Out of 135 total missions, 2 shuttles were destroyed in accidents [0].

While it is certainly great to aim for 100% success, it's helpful to remember that astronauts are willing to take measured risks in order to perform their missions, and that we must select rockets/etc from the options available, not from the options we might wish to have.

0: https://en.wikipedia.org/wiki/List_of_Space_Shuttle_missions


Although if you count F9-4 as a failure, you should also count the STS-51-F Abort-to-Orbit as a failure, which brings it to 3/135.


Probably STS-93 too.


These two bring up an interesting philosophical point. Are they successes of failures? To me, it sounds like engineering done right. "Something bad" happened, and yet the vehicle survived and even completed its mission.


Well then it's only 1 spacex failure.

People aren't arguing the merits of success they just want to use the same rules to talk about nasa and spacex


As I recall the original engineering estimate was a 2% catastrophic failure rate - i.e. loss of orbiter - on the Shuttle [1]. Columbia was STS 107. The estimate was spot on. You have to respect the level of engineering involved here.

[1] http://www.amazon.com/Development-Shuttle-1972-1981-History-...


As far as I know neither of those failures would have resulted in loss of crew. One was a partial failure where due to a partial engine failure they didn't make their secondary orbital insertion, and the other was a loss of vehicle that would have been covered by either the crew escape system, or the dragon capsule parachuting to safety.


Once they start to recover the first stage, they'll get a lot more information about how their systems really performed, as opposed to how they think they performed from the telemetry. You can do all sorts of testing on all the returned components, figure out how much of the margin of safety was actually used, and look for fatigue cracks that weren't quite bad enough to result in failure this time round. In principle at least, this could greatly increase the safety of future launches, at least as far as the first stage is concerned.


According to [1], the shuttle program ended with a failure rate of 1 in ~67.5.

1: http://www.popularmechanics.com/space/a6611/us-space-shuttle...


In the context of manned missions, it's unsurvivable failures that are unacceptable.


The original comment was clearly using a stricter standard than that.


I don't think anyone expects to strapping oneself to a rocket that packs the energy potential of a not-so-small nuke will ever be considered perfectly safe. And remember the failures they had would be survivable with the current launch abort system Dragon has.

There was a time sailing across the Atlantic was dangerous.


That's not very fair comparison for rockets. When people fly in B-747, it also has a pretty significant amount of fuel - and energy - aboard, yet safety complaints are rare regarding that.

So the goal for rockets - for now - could be to become as safe to ride as airplanes are. 100% safety is unobtainable, so shouldn't be a requirement.


"So the goal for rockets - for now - could be to become as safe to ride as airplanes are."

If you could build a spacecraft launch system with the weight budget of a commercial airliner, you could get that reliability. The fuel fraction for the Space Shuttle was about 85%; everything else, structure, engines, equipment, and payload, comes out of the remaining 15%. For an airliner, 60% of the mass is non-fuel. Spacecraft are weight-reduced too far to get aircraft reliability. They're just too fragile. Read NASA's "The Tyranny of the Rocket Equation".[1]

Space travel with chemical fuels out of Earth's gravity well is just barely possible at all. Chemical fuels just don't have the energy density to do the job well. It's necessary to launch huge booster stacks to put a dinky payload in orbit. That's why, after 50 years, space flight hasn't progressed all that much.

Without a denser power source, it will never get much better.

[1] http://www.nasa.gov/mission_pages/station/expeditions/expedi...


> the goal for rockets - for now - could be to become as safe to ride as airplanes are.

The energy an orbital rocket packs is significantly more than the full fuel load of a 747. The required performance is also much higher. Tolerances are much lower (because of the performance).

It'll be quite some time until they get to 747 levels. A worthy goal would be to become as cheap as a 747 at a reasonable safety level. That would be massively disruptive.


A more significant point is that the 747 carries only fuel, the rocket carries fuel and oxidiser, which substantially increases the variety of ways in which things can go interestingly wrong.


With the addition of the crew escape system plus nailing down the causes of their last failure, very much safer than any other manned launcher the US has had in service.


You think it's going to be more reliable than Saturn-V manned stack? Why?


Cherry picking the MANNED Saturn V missions conveniently leaves out the unmanned Apollo 6 test where pogo vibrations borked two of the second stage engines and caused third stage relight to fail.

And if you want to consider the whole Saturn V STACK then you're going to have to consider counting Apollo 13 as a failure. The "payload" for Apollo is, in the end, really just the Command Module.


We're a bit offtopic here :) but let me respectfully disagree.

The whole point of doing testing with rockets is to find what you don't know, validate your assumptions... What you usually don't know is when a thing will fail - and you don't want to learn that in a real mission, so you push the test article to extreme. Another reason to do tests is something which should work - and shouldn't fail - but you can't test that without actually doing a flight test.

So, in my opinion, cherry picking test flights - where things fail routinely, otherwise why testing? - doesn't show you the designed - and updated, with test data - reliability of the system.

Regarding whole stack - I meant the whole thing which lifted off and the part of which reached low Earth orbit. That stack had the pulling safety tractor rocket. But frankly, if I'd consider Apollo-13 flight, I'd assume we have the case of mission abort in a later stage of flight, after which the existing measures were taken to bring back the craft safely. So mission was aborted - just as it would be if, say, Saturn-V grossly misbehaved on 30th second of flight - and the systems worked on safe return.


I don't agree with the premise but as I understand it the crew escape system can work for the entire preflight+flight not just a certain window on the ascent.


That's a hope though, not a fact...


That's an estimate based on engineering analysis and statistics, just like any estimate of reliability.


It's not an estimate based on statistics, because there are no statistics for the system you are talking about. It is a prediction based on engineering analysis, and the prediction for space shuttle reliability was quite a bit better than the actual record turned out to be.

I want SpaceX to succeed as much as anyone (probably more since I work there), but one should not delude oneself into thinking that predictions are fact.


The regulatory and compliance checks for manned missions are considerably more rigorous than for unmanned ones. If you look back, manned missions have historically had much better success records than unmanned ones by the same operators.


Is 25 a sufficient sample size?


[deleted]


But this is space flight, not sex with some celebrity. It's worth far more risk.


Few things that are worth doing are risk-free.


This article from a few years back tries to quantify that answer...

https://reason.com/archives/2012/01/26/how-much-is-an-astron...


The entire company is firmly focused on return to flight. Sometimes failure can be a great motivator and, ultimately, if used as an opportunity to learn and improve, a good thing.


Humans are a dime a billion. We have no problem slaughtering humans daily in contrived conflict but somehow losing a few furthering scientific understanding is unacceptable.


First, this is an extremely naive view as to what goes into training an astronaut to be sent into space. It's not like we just plucked four random people from the globe and are sending them to space. These are people who are very likely at the top of their fields, have gone through rigorous (and costly) training, and are going up to do very specific jobs. These people are not a "dime a billion", and claiming so is the same as saying that if Elon Musk were to disappear today, that any other person could simply take his place and keep moving his companies forward.

Second, just because there are negative aspects in the world that cause loss of life, doesn't mean we shouldn't be doing everything we can to ensure a safe flight. This is unrelated to the cost aspect mentioned in my first point, but the average person living in the U.S.A is only living as comfortable as they are because modern civilization, for the most part, values safety quite high. It's a poor argument to say "Well X people died yesterday, so we shouldn't care so much about the 4 that might die in a launch".


> These are people who are very likely at the top of their fields, have gone through rigorous (and costly) training, and are going up to do very specific jobs

That is irrelevant to the level safety precautions. Unless you were trying to argue that their costly training makes them worth more than other people. I hope that is not what you were arguing.

> doesn't mean we shouldn't be doing everything we can to ensure a safe flight

At some point you have to declare something 'safe enough' since 100% safety is an impossible perfection. Bicycles aren't 100% safe, but we don't go around insisting on multiple backup systems. Personally I do find it curious that the standard of safety for astronauts is so high. The cynic in me suggests its less out of concern for the astronauts and more to do with the publicity fallout that occurs after disasters and the damage to other assets. The optimist suggests its more a concern for all the ground crew and spectators who are also at risk. There is potential for a lot more than 4 casualties when you play with that much fire.


>> These are people who are very likely at the top of their fields, have gone through rigorous (and costly) training, and are going up to do very specific jobs

>That is irrelevant to the level safety precautions. Unless you were trying to argue that their costly training makes them worth more than other people. I hope that is not what you were arguing.

I believe GP was arguing about the "a dime a billion" part. They are not worth more than other people in the human sense, but that doesn't make them any more common. It's just the fact that there are very few people with such qualifications that negate the argument of "a dime a billion".

And I guess it's also true that not any of those billions could be trained to be an astronaut for a myriad of reasons.


> And I guess it's also true that not any of those billions could be trained to be an astronaut for a myriad of reasons.

This is less clear. Even more, the space tourism industry relies on that to be false. To an extent.


Well, in part I agree.

But I think there is (or at least will/should be) a difference between a trained astronaut and a space tourist.

I mean, being an astronaut is more than just going to outer space, isn't it? A space tourist might do a lot of the stuff that astronauts do, but I think there will still be a fundamental difference. Astronauts are there to do research, push the limits on human capabilities, etc.

After all that is settled, then the tourists can come.


Well and think about planes. Planes are already safer than cars, but we demand very high reliability. If 30% more planes crashed and it cut ticket prices by 30%.. some people would make that trade. People do it when buying smaller less safe cars... but we don't like the thought of plane or shuttle crashes.


Of course, for cars you have the added problem of externalities: the bigger `safer' car actually causes more damage to others in a crash.


> Unless you were trying to argue that their costly training makes them worth more than other people.

I would imagine they are to the company that is launching them.


What astronauts are trained to do at the top of their field and what they end up doing are kind of divorced though. They spend an inordinate amount of time turning wrenches really, really slowly.


I think that's like saying that pilots spend an inordinate amount of time sitting in their chair making sure that the autopilot is working properly. The remainder is why they get all of the training that they do.


Divorced, but still related, I think. There are lots of possibilities to die in space, to kill fellow crew members or to seriously damage quite expensive equipment, so one should really know how to, e.g., turn wrenches.


You are making the appeal to common practice fallacy. Even if human death (or sacrifice) is a common occurrence, it does not make it acceptable.


Not only is it acceptable, it is necessary. How do you think our ancestors determined what was safe to eat? As the saying goes, sometimes you need to break some eggs. Now don't get me wrong, I'm neither condoning, nor encouraging, wanton negligence concerning human safety, obviously all possible efforts should be made to ensure it, but sometimes, such as in cases like this, the rewards far outweigh the risks.


Yes. And thousands have died in death camps to bootstrap our modern cariology. We should be grateful to all people who died in the past providing us data and knowledge, and to honor them we should use it in the best way we can, so that no one else has to die.


> How do you think our ancestors

Right, but that doesn't mean we should follow that just because the ancestors did that?

On the opposite, I'd hope for astronaut-level safety precautions be spreading for the rest of society, so everybody could benefit.


This type of comment was and is "a dime a billion"

"Thousands of people die in car accidents every year and..."

It's bizarre that anyone would find this type of comment insightful after all the times its been posted ad nauseam.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: