NASA Orders SpaceX Crew Mission to International Space Station
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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?
There was a time sailing across the Atlantic was dangerous.
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.
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.
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...
1: http://www.popularmechanics.com/space/a6611/us-space-shuttle...
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
People aren't arguing the merits of success they just want to use the same rules to talk about nasa and spacex
[1] http://www.amazon.com/Development-Shuttle-1972-1981-History-...
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.
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.
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.
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
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...
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.
That seems like a pretty significant oversight?
(I'm not sure if there was a reason or not)
> 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...
http://motherboard.vice.com/read/john-aaron-apollo-12-curios...
I guess we can forgive Bean for frying the color TV camera, then.
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.
Didn't it fall in the range safety exclusion zone, which ships were warned away from?
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.
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.
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".
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.
>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.
This is less clear. Even more, the space tourism industry relies on that to be false. To an extent.
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.
I would imagine they are to the company that is launching them.
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.
"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.
https://reason.com/archives/2012/01/26/how-much-is-an-astron...
I keep wondering if there will be a program where a group of 5 can hire a pilot/co-pilot and ride in a Dragon Crew into orbit. Spend the day there, and then fly home. If you are re-using the first stage at that point I can't imagine the cost is going to be more than a few million $ for each "astronaut".
With regards to the second comment, I can find out if you're interested.
If there is anyone that can pull this off at this fast pace, it's these guys.
BTW, if I ever charter a flight to the ISS, I'll have the Pan Am logo painted on the spacecraft.
Considering that the capsule still has the inertia from the main engine at the time where the separation/landing boosters fire it doesn't need that much to outrun the existing rocket since it pretty much just needs to get out of it's way.
In-Flight Abort is nice, but this is the 1st and only human piloted craft that has it, even if it will have quite a bit of risk attached to it it's still better than the competition.
Also, during an abort scenario, the aero drag is pushing Dragon back onto the launch vehicle, so you actually need more thrust to overcome that, too. (Although that obviously depends very strongly on the dynamic pressure at which you abort.)
Apollo had it - at least for during the first stage.
https://en.wikipedia.org/wiki/Apollo_%28spacecraft%29#Launch...
As for finding a space tourism company, I'd be interested if anyone had approached SpaceX with that as a business plan. I would certainly consider investing in something like that given the right team and opportunity.
It will also be symbolic for Americans: an American flag was presented to the ISS crew during the STS-135 mission (the final Space Shuttle mission). It is awaiting return by the next mission that is launched from the U.S.
I find it very interesting how the human sense of belonging to a group carries on as we keep, as a society, moving forward.
Arguing in favor of, or against it is not really what concerns me, but instead just observing how we change as we move closer and closer to the possibility of having to leave those old notions aside. I guess that's why it's common in sci-fi to have people born in other world have no sense of belonging to the Earth.
Probably a lot of the reasons for making it a big deal to return the flag in a US-launched vehicle has to do with PR, but still I can imagine that both engineers and astronauts will be very proud of making that happen nonetheless.
It's another confirmation to what I already suspected.
That robot/alien overlords will have no pity on the human race.
— Here’s the reason: The vast amount of brains, talents, special skills, and research facilities necessary for this project are not in the government. Nor can they be mobilized by the government in peacetime without fatal delay. Only American industry can do this job.
Destination Moon, 1950 (Loosely based on the book The Man Who Sold the Moon by Robert A. Heinlein, written 1949, published 1951)
So were Douglas, Grumman, North American and Rocketdyne. Those were the companies that put men on the Moon.
So too is Orbital Science, which has been launching satellites on a commercial basis for 30 years.
There's nothing 'significant' about the status of SpaceX as a company.
Now from GEO/HEO to anywhere else it's quite easy to get because you are pretty much near the escape velocity so it takes almost no delta-v to get pretty much anywhere you want in the solar system, at least as far as getting to a higher solar orbit goes as the closer you get the faster your solar orbital velocity is so using that speed to get even to the edges of the solar system takes very little energy. If we talk about say a mars shot then most of the energy in that trip goes to 2 things, getting to high earth orbit, and then slowing down for a mars capture the amount of fuel needed to do the martian orbit transfer is almost negligible.
>you don't need to scale "go fast rocket" up by that much
My napkin math says you need at least 2 orders of magnitude more fuel mass which classifies as "a lot"
Altitude is the easy part, relatively speaking. Getting the speed for LEO is the hard part. The GoFast rocket you linked to has demonstrated up to 4,200MPH. Low earth orbit requires about 17,000MPH.
That factor of ~4 requires massively larger rockets, because the rocket equation is cruel. Each incremental increase in final speed requires an exponential (actually using this word correctly, for once) increase in the amount of fuel. Fuel in return requires more hardware like tanks and engines, which means yet more fuel is required, etc.
Edit: using RP-1 as the fuel in a single stage, getting to 4,200MPH requires that 45% of your total rocket mass be fuel at launch. Getting to LEO requires 94% of the mass to be fuel.
The difference in ISP between a liquid-fueled rocket (say 450s for LH2/LO2, 350s for RP1/LO2) and solid propellant (250s) makes a huge difference to your prop fraction. To get, say 8km/s delta-v, just plug it into the rocket equation:
LH2/LO2: 6.1 initial/final mass. RP1/LO2: 10.3 solids: 26
Staging can help this a bit, but the basic fact remains. It's very difficult to get useful payload to orbit with solids.
It needs to go 4 times faster, and no, a 20% larger rocket won't cut it. 20000% larger by mass would be more like it. It also needs a 2nd stage burning liquid propellant with high specific impulse which is way, way harder to build than a dumb solid propellant rocket.
Noone (not even governments) has been able to send a single stage rocket to orbit.
Also 20000% larger by mass? want to be a bit more serious? if you scale this rocket by 35-40% you get to about the size of the first stage of the Shavit solid fuel space launcher which is a commercial space launcher.
You do understand how scaling works on 3 dimensional objects right?
The GoFast Rocket weighs 350kg. Scaling it by 35% (1.35 ^ 3) would make it weigh 861kg. The rocket you mentioned weighs between 30 and 70 _tons_.
I'm not sure you understand how anything works.
Based on my previous conversations with this guy, this seems to be a recurring pattern. I do hope that he's using these conversations to recognize and fill in the holes in his knowledge. :)
Edit: I see Shavit can also launch in a three stage configuration. My overall point remains.
Math is done with numbers, so let me give you actual numbers. You can double-check these against https://en.wikipedia.org/wiki/Orbital_speed#Tangential_veloc....
Standing on the surface of the Earth your potential energy relative to infinity is −62.6 MJ/kg. If you were standing still 160 km up, you've added roughly 1.6 MJ/kg. (You climbed 160,000 meters against a force of 9.8 Newtons per meter.)
To then go into orbit you have to add a sideways velocity of about 7800 m/s. Apply the famous kinetic energy = 0.5mv^2 and going into orbit requires 30.4 MJ/kg of energy. That's 19x more energy than is required to get to altitude!
But it gets worse! If you're going to go into orbit, you need to think about getting down. Going up we go straight up out of the air and then add sideways velocity. Going down we let the atmosphere do most of the work of slowing us down. But in order to survive that you need a much more rugged device with a heavy heat shield. You're now both doing more work per mass lifted AND you're lifting more mass!
But we're not done with the bad news. A fundamental fact about rockets is that you have to lift the fuel you use later in the launch. That means that as you're increasing the final velocity you're getting an ever-decreasing ratio of energy expended to useful kinetic energy for your payload.
Put it all together and actual rocket scientists have told me that it is about 100x easier to get to orbital altitude than it is to actually get into orbit.
That said, LEO is the half-way point. Getting into LEO takes about as much energy as it does to launch from LEO entirely out of Earth's orbit.
It takes a 8 km/s horizontal velocity just to stay in orbit. That is in addition to the 2 km/s to just get to the right altitude.
So just by speed ratios orbit is 5x the difficulty of a space hop. In reality rocket scaling is exponential (you need more fuel to carry more fuel...)
Anyway, I do think nowadays "amateurs" actually could build orbital rockets with budgets in the low millions class. Modern electronics and GPS make it a bit easier than a few decades ago.
US-government mandated
The MTCR has 34 members, basically the G20 minus China and India. Since the MTCR doesn't have any provisions for enforcement, (It's "an informal and voluntary partnership") its US equivalent is the International Traffic In Arms Regulations Act. (Category XV, Section c, if you want to read how the US statute words it. In imperial units, of course, just to make things simple.)
No amateur rocket has made orbit or even come close. The difficulty of building a vehicle to make LEO is not comparable to building one to raise altitude once in orbit. LEO to GEO is less than half the delta-v of surface to LEO. It is routinely done by satellites alone. The only reason getting to GEO is particularly hard is because you have to get to LEO first.
You are right about transfer to Mars, though.
Now, accelerating a Mir-sized craft towards Mars and decelerating it to orbit while keeping the crew alive for a year outside the Earth's benevolent magnetic field and having enough fuel to accelerate back to Earth (even assuming we'll throw out the interplanetary craft and get to Earth on a capsule) is quite an impressive engineering feat. I'm inclined to suggest that, instead of building a vehicle like that we build one or more cyclers that will orbit the Earth-Mars-Sun system periodically and astronauts would only need to reach them in order to get back and forth. This way we pack all shielding for the long-duration trip into the cyclers and astronauts only need to carry the consumables they'll use. Since reaching them would be time-critical (they won't stop), I would suggest building a similar one that could be stationed in Martian orbit to serve as a fallback plan in case a crew misses the one cycler and has to wait a couple months for the next bus home. These two spacecraft are, essentially, space stations with clever orbits we could maintain with regular resupply missions just as we do with the ISS, but we'd need beefier rockets because the delta-v is the same as a craft going to Mars (because that's what it's doing). Luckily, we'd only need to accelerate the resupply craft - living space is "free" after the first burn.
I am uncertain if these craft are more or less complicated than building and landing the Mars ascent vehicle (much worse than landing a crew capsule, for sure). This sounds very complicated to me.
You don't need to ship enough fuel to return to Earth in the same trip as a manned crew.
You can send orbital depots for return fuel and ascent\descent vehicles ahead of time in unmanned missions. This could be done multiple years in advance.
When you are launching the crew and interplanetary habitat, you only need to bring enough fuel for a one way trip.
"The contracts call for orders to take place prior to certification to support the lead time necessary for missions in late 2017, provided the contractors meet readiness conditions."
There is plenty of time for NASA to back out if either of the companies don't meet the milestones.