Am I the only one finding the last 2 BO videos highly disingenuous ?
As mentioned numerous times, there's the whole "reaching space" vs "going into orbit" before landing.
More important to me is the fact that SpaceX is streaming its different tries in _live_, taking the risk of crashing the rocket out in the open. How many vehicles did BO lose before achieving a vertical landing ?
Oh, and what about the fact that they have total control on the location and time of the launch ? Meaning they basically control weather to an accuracy no one launching anything useful into space has. For example, last failed SpaceX landing was officially linked to fog icing the leg locks. That's not going to happen if you launch on a clear day from the desert.
These are more comparable to the Grasshoper tries than to anything SpaceX has done recently : no horizontal speed, full weather control, no reporting on failed attempts, very limited weight. Even the last grasshoper video seemed to have more side winds that had to be countered than this 100k altitude video.
Even the format of the video itself screams "vaporware" to me. It looks like a trailer for a bad action movie, where some spacey something goes to space, separates and lands back in 15 seconds. When the grasshoper videos left me in awe, looping over them 5 times in a row, the BO ones just make me feel like they sh/could end with some sexual innuendo over their big rocket
You're the one turning it into a competition, in reality it is simply two separate companies doing different awesome things. Yes, obviously, going into orbit is harder than not doing so. But going to space sub-orbitally is still very difficult and cool, and the only reason there's a negative spin on BO's achievements is because people feel the need to compare it with SpaceX as if there can be only one.
Just be excited for the positive direction of spaceflight in general. Everyone benefits from both companies doing well, even if SpaceX is ahead of everyone else for awhile.
I wish I had the power to turn that into a competition, but I don't think they need me for that :)
Jocking aside, I don't think there can only be one. I am comparing BO and SpaceX the same way I'd compare google and apple. In the same industry but not doing exactly the same thing. And when Apple tried to go on one of Google's turf with maps, they sucked. When Google tried to go do phones, at first they sucked. Comparison is natural and welcome.
Here, it feels to me that BO is putting themselves up for comparison for no reason.
As far as the positive direction of spaceflight, I think that transparency is key. Space exploration needs more accountability and trust that ever has been available before _in_any_industry_ever_. And there, so far SpaceX is winning hands down, including versus the old players (soyouz, ariane, ULA...). When SpaceX says "one of our struts was structurally deficient, broke down, made the rocket lose equilibrium and ultimately explode", they're also telling their competitors "Watch this. We've learned it the hard way.". Same with fog icing the leg lock. In the grand scheme of things they are making space safer, and not only for their customers. I only see bragging and borderline (note the "borderline") bullying on BO's side
I agree on the form (SpaceX is much more open and less advertish about its tries) and on how late BO is compared to SpaceX' technology.
But I feel that would be OK if BO hadn't mentioned space tourism in the past.
First, getting an assessment of how safe this "holiday travel trip" is compared to going to some exotic place by plane requires a hundred times the number of tests they have made. Compare their two runs to the number of kilometers that Google has driven their autonomous cars.
According to Wikipedia, in 2006, they claimed to go commercial in 2010, which tells me they are phenomenally overoptimistic. In the case of space exploration, this is really, really dangerous. Were they to go commercial too soon, a catastrophe implicating civilians could cause a space exploration winter.
Musk's vision is more rational. First, control as much of the solar system as possible while putting as few human lives at risk as possible, then, when civilians can live sustainably in another planet, orchestrate a colonization.
One part of the article that gives me hope is this:
> We’re already more than three years into development of our first orbital vehicle.
Why does this have to be a zero-sum competition? Can't folks just be excited about space tourism? SpaceX and Blue Origins are basically different industries right now, with slightly complimentary tech.
you're right, it doesn't have to be a zero sum game. They could be cooperating. Only the propensity of either of the competitors to claim their success without acknowledging the other's advancement makes it look like a winner-takes-all game.
As far as space tourism, I feel like it's just that : tourism. Reserved to more and more concentrated elite and pretty short sighted. There's no problem with being excited about it, but it's better to also do something meaningful about it, other than signing a check and posting some cool instagram picture of your 30 seconds vacation. Even if it's just understanding how much effort was put in getting you there.
Marketplace competition and non-zero-sumness are not mutually exclusive, at least not if you are a capitalist. The total money spent on spaceflight will be larger with both companies in the market than with either one alone, therefore it is not a zero-sum game.
As for acknowledging each others advancements - you don't see Sony or Dell going out of their way to mention Apple, for obvious reasons. This is normal behavior between competitors. I don't see why people are making so much out of Bezos' tweet; it was just a stupid joke.
Maybe because expectations of friendliness are higher when talking about space industry. It still feels more like few entities working towards the same grand goal than companies competing with each other.
The jabs Elon and Bezos are exchanging seemed funny to me at first, but now they seem kind of serious, which makes me uncomfortable. I expected they'll have fun together, not the resentment that seems to be flying between them.
space tourism will become much cheaper very soon, the last 3 weeks we have had massive accomplishments in space. To get comfortable going to another planet, surely people will need to be normalized to the idea of space, which is what the value of space tourism is, besides the obvious superlative nature of it.
I personally doubt that. No matter what, the fuel will still cost in the $100k, plus the marginal cost of the vehicle, launch authorization, coordination on the ground and having an emergency team ready to dispatch at a moment's notice.
That stuff costs money and if you're only launching 5 people at once, it's still a high sticker for each launch. While "regular" vacation scales pretty well with the number of people you're going with, it's not going to be the case for space exploration.
On a regular vacation, most of the cost overhead for each additional person is the transportation cost. Here, the vacation _is_ the trip
I used to be critical of BO for exactly the same reasons, but this video changed my views, because I'm pretty sure SpaceX and BO roadmaps are going to be completely different:
- SpaceX wants to enter the traditional rocket market, and use that money to slowly but surely extend into reusing rockets. This means that the most important thing is actually putting stuff into orbit, which also means that they won't do any launch that has less than a Falcon 1 capability. SpaceX has so fare managed to land 1 rocket but not reuse it.
- BO wants to enter the space tourism and do that through rocket reuse. Since there is no space tourism market yet it all has to be funded privately though. However space tourism is an entirely different beast; the requirement, for the moment, will only be to hover over the Karman line and glide back to earth safely, which is much easier than what SpaceX is doing, which means they can concentrate their efforts on other more important parts. And we've seen that in the video: they've been able to reuse a rocket, ie do what everyone is chasing, and do it successfully.
Elon Musk wants to colonize the Solar System; he's in for the very long term. BO "just" wants to send people high and get them back to earth for cheap. BO has a much more attainable goal, but they have made a bigger dent into that by reusing their first rocket.
A big dent in a thimble is nothing alongside even a small dent in a truck.
You're not all wrong, but BO is being disingenuous, as top poster said. They're trying to make it look like they're ahead of SpaceX, which is laughable. If SpaceX wished, they have been doing years ago what BO is doing now. But they were trying to accomplish something more meaningful than a tourist resort.
Someday, they will be history books written about SpaceX alone. The same will never be true of Blue Origin.
Thats exactly what upsets me, not what BO is doing, but that they're so obviously trying to take advantage of the SpaceX hype and appear to be ahead of them.
Oh, and what about the fact that they have total control on the location and time of the launch ? Meaning they basically control weather to an accuracy no one launching anything useful into space has.
This is precisely what you want for space tourism, though: control over variables to ensure high margins of safety.
Even the format of the video itself screams "vaporware" to me. It looks like a trailer for a bad action movie, where some spacey something goes to space, separates and lands back in 15 seconds.
Maybe what you want for space tourism, though. You want as wide an audience as possible. Most folks don't know the difference between BO and Falcon 9. Most don't know the difference between a suborbital hop and achieving full orbital velocity. People keep buying tickets to Michael Bay movies. If we can get some of that money for reusable space vehicle development, seems good to me.
I'm upset, but very little, and it's because of broken expectations - I thought better of both Elon and Bezos. Otherwise, as you said, both succeeding is a net win for humanity, so I cheer both.
"The BE-4 is our fourth-generation liquid rocket engine, made to take us into orbital space and beyond. Using the latest design and manufacturing techniques, it’s made for both commercial and government missions."
That compares things location wise, but it misses out entirely on comparing the speeds, the difference of speed is a huge element in comparing the two efforts, in fact it is the distinguishing factor.
Randall Munroe explains this very nicely in his piece on Orbital Speed[1]:
> But getting to space is easy. The problem is staying there.
> To avoid falling back into the atmosphere, you have to go sideways really, really fast…The speed you need to stay in orbit is about 8 kilometers per second. Only a fraction of a rocket's energy is used to lift up out of the atmosphere; the vast majority of it is used to gain orbital (sideways) speed.
Nah, I watched the video. There's nothing disingenuous about it. You're simply turning it into a nerd fight. Microsoft vs Apple. iOS vs Android. SpaceX vs Blue Origin. I'm glad to see two companies working on the problem going at it from different paths. I hope they 're both successful.
Re-usable rockets had never been done before (except perhaps the Space Shuttle, although a different concept). This is the 0->1, and now Blue Origin can work at incrementally flying higher with larger payloads.
Certainly not to take away from what Space-X has done - they've set many records themselves and operating commercial launches, which BO looks to still need time to do.
Honestly just roll my eyes now at these pissing contest blogposts from Bezos. He does his team a disservice by suggesting that what they are achieving is actually more advanced than what SpaceX has done - it all looks like the approach the Soviets took in trumpeting various "firsts" in space in the 60s as the US methodically built capability far beyond what the Russians could sustain.
I am impressed by both companies' ambition, and SpaceX clearly has both the time and money advantage over Blue Origin. Let your accomplishments speak for themselves.
> US methodically built capability far beyond what the Russians could sustain.
You know what year it is, right? This is not 1998. Unfortunately US "sustainable" technology is mothballed and we are flying into space on Soviet technology. I hate the commies on principle, but at the end of day you gotta accept reality here.
> Soviets took in trumpeting various "firsts" in space
Also I can think of just a few firsts off the top of my head :
First satellite, first ICBM, first human in space, first probe to reach moon, first EVA.
Then looking up on Wikipedia I found: first probe launch to Mars, first probe launched to Moon, first probe to reach another plane (Venus), first unmanned rendezvous and docking, first permanently manned space station.
And even the first fully automated flight of a space shuttle system. Which they did to show off, and then also realized "it was found too expensive to operate as a civilian launcher". It took US how many years and disasters and money to realize that?.
Ontop of all of this.. ULA's heavy lift capability is entirely dependent on Russian engines to reach orbit.
Made much worse by the fact ULA had until SpaceX arrived, complete monopoly of the US defence market.
It does make me wonder how much of this is just follow on from the exact events you described. Specifically that the Russians were for the longest time far ahead in liquid fuel rocket engine technology.
> ULA's heavy lift capability is entirely dependent on Russian engines to reach orbit.
Huh? ULA's heavy lift capability is dependent on the Delta IV (specifically the Heavy variant), which does not use Russian engines. ULA's most economic launcher, Atlas V, uses Russian engines however.
Indeed. The Delta IV Heavy is priced out at above $1 billion per launch, and a regular Delta IV launch is probably about 2-3x as costly as an Atlas V, which itself is about 2x as costly as a Falcon 9.
They still are very ahead — of course, the Merlin and RS-25 are amazing designs, but they're still more of the brute-force American methodology that made the Saturn V so brutally effective at travelling to the moon. The Russian aerospace industry has always tried to approach rocketry with a lot more emphasis on finesse, precision, and clever engineering solutions — the astonishing reliability of the Soyuz is a testament to this. von Braun and his team at Marshall always pulled off amazing technological feats, but at the expense of greatly increased complexity and less efficiency. That legacy has largely carried on to the present day; I hope that this newer generation of American LVs (Falcon 9.1R, Vulcan) will turn things around in the opposite direction.
What's great about Blue Origins long term is the frequency of launches. Blue Origins will be launching a rocket every day years before SpaceX will, because of obvious differences in rocket magnitude and mission.
There's a fair amount of boilerplate that comes with launching a rocket. From the command terminals (and associated IRL command structure) to the pod's parachute and rocket assisted landing , all components will be used and tested A LOT thanks to Blue Origins' strategy.
Assuming Blue Origins learns as much as possible and iterates on any sliver of weakness, we as a planet can be far more confident in the human carrying structures that are used to transport space-to-surface. SpaceX undeniably has more impactful and impressive rocket technology, but I'll always respect the lower level work Blue Origins is focusing on.
Space is really, really, really hard. Everyone wants to go up, I enjoy how much Blue Origins wants to come back down. :)
Space-X does have a problem with launch rate. They have a backlog of 50 launch orders and are about two years behind. They stopped posting future launch dates on their web site last year; comparing old launch manifests with new ones made their slip rate too clear.
The plan was to open their Brownsville TX launch facility this year,
but they've having foundation problems and may slip to 2018.[1]
The first Falcon Heavy is supposed to launch this spring/summer. That will be a major milestone. Nobody has launched anything that big since the Saturn V.
BO is sub orbital meaning their rockets don't actually break out of the Earth's gravitational field. What they are doing is hard, but much easier than what SpaceX is doing.
For the BO missions, their rockets travel Mach 3.7 (3.72 was the exact top speed from a previous launch). This is called Suborbital. In comparison, since SpaceX is trying to break out of the earth's gravitational pull, its first stage goes around Mach 10 (per the media package of CRS-3).
This article does a better job putting things in laymans terms:
In short, the Falcon 9 has unbelievably more thrust than the BO rocket due to being designed for carrying payloads into outer space, not simply small objects into suborbital flight. Both are necessary and both are amazing.
I believe I might have completely misunderstood what "lower level work" meant. I took it for "more fundamental work" in opposition to "easier work". My bad
Worth noting though, that as mentioned (announced) in this post, they are working on an orbital vehicle too. Part of this is the development of the BE-4 engine, which will also be used on the orbital ULA Vulcan rocket.
> Blue Origins will be launching a rocket every day years before SpaceX will
I would stake my life on you being dead wrong, that's how fucking positive I am. It's such a silly thing to suggest! SpaceX has made dozens of launches, Blue Origin has made a couple ! What in the world implies to you that their rate of scaling will soon outpace Spacex??
The fuel cost of a Falcon 9 launch is ~$200k. In a perfect world (tons of launches), lets say (generously) that we get launch costs down a million a pop, all things included.
BO's New Shepard is shooting for something like $100k or less per flight. The rocket is much smaller, uses less fuel, and is much easier to move around on the ground, reducing fixed launch costs. It's at least an order of magnitude lower in price, for a completely different service (suborbital tourism), which will make it accessible to a much larger market.
Larger market? I think not. The space launch biz is populated by hundreds of different companies, all wanting to spend millions or billions to get a useful sat into orbit. BO is looking to a small group of billionaires with the money to throw 30-50k to spend a few minutes vomiting. And of those, only the ones young enough to participate, a rare thing amongst billionaires.
(1) The launch is not gentle. Everyone will be strapped tightly into chairs, ready for launch escape rocket thrust if necessary.
(2) Time weightless will be measured in minutes, probably less than ten. So nobody is getting out of the chairs. At best they get a few minutes of watching pens hover, unless that is everything has to be secure. In such cases only the vomit will float.
(3) The landing options are not great. Soft if all goes to plan, but parachutes/hard if no. So everyone stays in chairs. No old people and/or heart conditions need apply.
How many people pay to ride the vomit comet every year? How many of them are billionaires? That's BO's market.
The Falcon 9 first stage accounts for only 3/4th of the launch cost[1]. Given the $60M+ [2] total current launch cost, that still leaves $15M even if booster reuse is free.
SpaceX no longer has plans to develop second stage reusability for the Falcon[3].
There's a number of reasons, most notably rocket size. I'm not sure that SpaceX will ever have a rocket every day, and that's okay. I realize it's heresy to question Musk's omniscience, but it's very possible to outscale SpaceX, and that in no way diminishes what they have and will accomplish.
You're assuming a large demand for space tourism and little suborbital hops. Once the novelty wears off and the 0.1% who have the money and want to experience it have gotten their ride, then what is their business model exactly?
If SpaceX get their launch cost per Falcon 9 down to the close order of $1M, and succeed in re-using Dragon 2 for multiple flights, then that's a price on the order of $100-200K per seat to orbit.
If Bigelow then have an inflatastation on orbit -- made a whole lot more plausible with Falcon Heavy on-stream and semi-reusable -- then there's a plausible market for real space tourism (as in, stay in a hotel for multiple nights in orbit) for under $1M, possibly considerably less.
What's the next step? Some kind of Earth Departure Stage and a lunar fly-by?
Just speculating here, but Blue Origin's current rocket is purely sub-orbital. It'll tap out the $100K space tourism market really fast. While SpaceX is building a commercial launch manifest and the infrastructure to support orbital and trans-lunar space tourism as a hobby on the side (I'd expect Musk to go this route with free rides for billionaire potential investors when he's gearing up for Mars).
Oh, I'll bet National Geographic is already thinking about ways and means of recording and monetizing a "Return to the Moon" mega-documentary before 2030. It'd probably be do-able by 2022 for on the order of $1Bn with Apollo-levels of risk and the equivalent of a Block 1 LEM (two astronauts to surface, 24-48 hour excursion, no rover); assume half the money goes on developing the LEM and the rest on Falcon Heavy launches. By 2030 it'll be the same price, but a whole lot more comprehensive (a 4-6 body crew, multi-week excursion).
Utility of Blue Origin's current platform in developing such a "real" space tourism market? Approximately zip.
Yeah this is basically what I'm thinking. It seems like Blue Origin might be able to do some brisk trade for awhile in Russian billionnaires who can drop $100k to hop up into space and impress whatever supermodel they're trying to woo this week. I don't see that ever getting to a launch-a-day.
I did look up the company, though, and they plan on building vehicles that can compete with the Falcon 9. At that point the competition would start to get more interesting since that opens the doors to everything you just mentioned SpaceX could wind up doing. SpaceX is launching Falcon 9's now though...
Shipping perhaps? Is there a place for science that is covered by satellites or weather balloons? Perhaps deploy emergency connectivity faster than a satellite can be launched? Just thinking out loud here, I'm sure there's tons of applications I haven't considered.
>Perhaps deploy emergency connectivity faster than a satellite can be launched?
New Shepard points straight up for the entire duration of the burn (110 seconds), because the goal is to get the payload to just barely 100km and then land more or less in the same spot. Any object on this ballistic trajectory will fall down to Earth very quickly.
Project Loon is better for communications equipment - the balloons stay up for longer, they are closer to the ground (essential for low power applications), and they're much cheaper to launch. https://www.google.com/loon/
Sounds like a rather weak comparison, as USSR did manage to get a set of impressive results in space - at least as American specialists were characterizing them.
Not sure if SpaceX really has more money than BlueOrigin - that used to be the other way around. Time advantage is clearly on the side of SpaceX though.
Once US was landing on the moon? What kind of achievements you'd like to have?
Planetary probes, like Lunokhods - several weeks of Moon exploration? Or Luna-16 - automatic probe which brought lunar soil to Earth? You can say that's less impressive than Apollos, and I'd agree, but that still different things - which USA couldn't do at the time, and those programs had some advantages over Apollos too. Or a series of Venera probes, including landers? Mastery of automated docking? Orbital stations - starting with Salyut-1 - with myriads of experiments (medical, industrial etc.)? Rocket engines - more advanced than American ones by such criteria as working process (gas-gas was tested during 1960's in RD-270 with single chamber thrust rather similar to F-1), Isp and mass ratio (NK-33), total thrust (RD-170)? VEGA comet fly-by?
Actually a Venera lander was the first and only (so far) which returned a picture from the surface of Venus. Brilliant engineering imho. Not to mention the MIR space station.
They did use parachutes a bit eg. Venera 14: "After entering the atmosphere a parachute was deployed. At an altitude of about 50 km the parachute was released and simple airbraking was used the rest of the way to the surface." The atmospheric pressure at the surface is 94x Earths so it slows stuff quite well.
Heh. True. What struck me when reading about these probes was more the final descent - dense balls of metal and electronics like the Venera probes had terminal velocities around a walking pace.
They got several probes onto Mars. That's just off the top of my head, though. The Soviet space program was no joke. Though it may have been a combination of brute force and revisionist history over their failings. I personally suspect there are a lot more human corpses in orbit than anyone knows about.
Well, USSR had a really hard time with Mars landers. AFAIK, they got just one landed - and it stopped working shortly after that. But that one landed before Vikings.
People forget how Mars was known as a graveyard for probes for many years. It's only fairly recently that anyone including the US has been able to deliver payloads to Mars with any reliability.
They were also pioneering in the space station/space habitat arena. We have the Russians to thank for a lot of the technology aboard the ISS, both when it was being built and to this day.
There's also the fact they were the first in space with a true orbit. Whereas Alan Shepard was simply on a ballistic trajectory, much like Bezos's launch a couple of weeks ago.
Also Mir.. They still have more knowledge when it comes to staying in space for longer periods of time. Landing on Venus..
> When you do a vertical landing, you’re solving the classic inverted pendulum problem, and the inverted pendulum problem gets a bit easier as the pendulum gets a bit bigger. Try balancing a pencil on the tip of your finger. Now try it with a broomstick. The broomstick is simpler because its greater moment of inertia makes it easier to balance. We solved the inverted pendulum problem on New Shepard with an engine that dynamically gimbals to balance the vehicle as it descends. And since New Shepard is the smallest booster we will ever build, this carefully choreographed dance atop our plume will just get easier from here.
I don't know who started this pissing contest but from what I heard it started when Bezos hired a top engineer away from SpaceX for Blue Origin, basically poaching.
Either way, Bezos can p--s all he wants with his shorter rocket that carries less and goes to lower height when SpaceX rockets carry more and go higher.
And not to mention Elon literally bet his farm to get it going during hard times...
I agree with this. But Jeff makes a valid point about judging the rocket by its smaller size. The launch of orbital vehicles is a solved problem, but landing the booster is newly under development. The smaller booster is harder to land vertically, so the technological solutions they are testing may prove to be more robust in adverse conditions.
I don't think the smaller booster is harder. It's almost by definition easier. It weighs less, doesn't need to reach orbital velocity and can have an engine that throttles all the way down to hover because the MTOW is not that different from it's dry weight. Not reaching orbital velocity is the main thing here, it's what makes all of this easy in comparison.
The solutions they are exploring are many times less complicated and difficult than what SpaceX is doing. Saying otherwise is mischaracterising both of their achievements.
The dynamics problem of balancing an inverted pendulum gets easier as the distance between the COM and the force input is increased.
Of course, its also easier to have very fast gimballing on a smaller engine, and a taller rocket bends more which makes it harder to detect exactly where it's pointed in the first place.
The pendulum fallacy has to do with the tail of the rocket not naturally following the head during launch. Landing really is an inverted pendulum problem.
How is even the landing an inverted pendulum problem? There's no instability of an inclined rocket during the landing; there's an instability of a "gimbaled-away" rocket. That's not the same thing.
I'm not sure what you mean by that. How is this different, mathematically, from the classic 8th grade textbook picture of a child balancing a yardstick on his nose?
Both forces go through the centre of mass, as the engine doesn't stay firing vertically downwards when the rocket rotates. Your finger on the other hand tries to continue pushing upwards as the yardstick rotates about your finger, whcih means the centre of mass of the yardstick moves laterally comapred with the vertical upwards force you apply with your finger. Thus, it creates a moment and rotates.
If you draw a free body diagram, weight is down and thrust is forward. Both force pass through the center of mass so they don't impart any moment to the rocket. So it has no tendency to fall over. They do impart a net horizontal force so it has a tendency to run away sideways.
For the broomstick, weight is down but "thrust" is both up and forward. So there is a moment caused by weight at the CoM and up-force at the base.
Easily. The yardstick is unstable in inclination if it isn't vertical. The rocket is unstable in horizontal position if it isn't vertical. But it doesn't start to rotate as long as the thrust vector goes through the CG. The thrust vector has stable orientation relative to the rocket (if you don't gimbal), whereas the force vector doesn't have stable orientation relative to the yardstick.
> The thrust vector has stable orientation relative to the rocket (if you don't gimbal)
This is what makes your argument moot - because they do gimbal, and the gimbaling is what creates the moment/torque. In a way that is very nearly analogous to twisting your hand around slightly to balance a broomstick.
> The yardstick is unstable in inclination if it isn't vertical. The rocket is unstable in horizontal position if it isn't vertical.
The rocket is unstable in position and inclination (attitude). So you're right that there's more to it, but it's still the inverted pendulum problem for attitude, plus the rocket formulas for translation and added constraints of landing location. Are you saying Bezos is lying in this post when he explicitly says "When you do a vertical landing, you’re solving the classic inverted pendulum problem"? He would know, and I don't see a reason for him to lie about it.
Fair call on the gimbaling at the end, in that instance it does impart a moment around the CoM and will invoke a torque, though that's really only at the end once much of the vertical velocity is cancelled. As a result it does represent the inverted pendulum right before landing.
Interestingly, because the CoM is so low due to the low volume of fuel by the time of landing, it's likely not as big a torque as you'd first expect (all the mass is down the base where the engines are). In that case, rocket height isn't going to have as a big an impact because it's not like it's equally dense up the entire rocket structure. I'd argue he's likely overstating the effect of rocket size on how difficult it is to achieve.
> This is what makes your argument moot - because they do gimbal, and the gimbaling is what creates the moment/torque. In a way that is very nearly analogous to twisting your hand around slightly to balance a broomstick.
The point of the inverted pendulum problem is that the torque on a long, thin, ground-supported object (or even just any ground-supported object with a narrow base or a hinge on its bottom) is a function of its orientation. That gives you a second order differential equation for tilt. This is NOT the case with the free-flying rocket because the engine is rotating along with the rocket. You could simulate the inverted pendulum actively, by rotating the engine so that it has a fixed orientation relative to the ground (up to the gimbaling limit, which is usually <10 degrees), but you actually want to do the opposite with the landing rocket (with significant damping to boot). Basically, you want the active control system to simulate a normal pendulum, just turned upside down (but with the damping so that it doesn't actually oscillate).
> The rocket is unstable in position and inclination (attitude).
Not the latter unless you make it behave in that way. You could also check on the Apollo LM landing guidance, maybe it will become more clear if you study that.
> So you're right that there's more to it, but it's still the inverted pendulum problem for attitude
No, it's not. That's the point.
> Are you saying Bezos is lying in this post when he explicitly says "When you do a vertical landing, you’re solving the classic inverted pendulum problem"? He would know, and I don't see a reason for him to lie about it.
No, I'm saying that this phrasing makes no sense. Remember that Goddard made a similar mistake when reasoning about rockets and pendulums, so arguments to authority are demonstrably to be avoided here. A significant clarification on his part could make it more comprehensible what he actually meant, but making any kind of analogy to a ground-supported object is clearly bad when talking about a free-flying body.
The yard stick has a normal force vector from the hand passing through its center of mass. It doesn't start to rotate unless an outside force is applied.
Of course in the real world it requires active control because the most minute misalignment causes a feedback that moves it further out of alignment. The rocket is exactly the same, if the thrust vector is not directly between the center of mass of the rocket, and the Earth, it starts to tip over.
If it were a stable system, misalignment would push the system back into alignment.
It's not the case with a rocket, unless you're flying forward with a liquid propellant rocket and the fuel tanks are almost empty so that the center of mass is significantly behind the center of drag (and the atmosphere is appreciable). That is an inverted pendulum situation.
Outside of atmosphere and/or at low velocities, there's no instability of this kind, and "flying backwards" (=landing) makes the rocket actually auto-stable (like with a dart), even if the time constants may not necessarily be meaningful for useful control here.
The engines are attached to the rocket. Unless the engines are deliberately twisted, the thrust vector is going through the center of mass at all times, regardless of tilt.
So if a rocket tilts in flight, it will not tilt further and it will not fall back.
The yard stick, if tilted, will tilt further still and eventually fall, unless caught.
I don't see how that can be true. The rocket will still start to rotate even if the thrust vector goes through the center of gravity, unless that vector is exactly vertical (a point of instability). As I understand it that's the key insight to the pendulum fallacy.
No, it won't, because neither the thrust vector nor the gravity causes a moment in this situation. The key insight to the pendulum fallacy is actually that this situation doesn't create orientation-dependent momentum. That would make it a pendulum, but it isn't like that, hence the "fallacy" part.
I see what you're saying. That would imply in the absence of an atmosphere a gravity turn isn't really possible. You'd pick up horizontal velocity, relatively slowly, but assuming you didn't exert some kind of control your rocket would always stay at the attitude it had at the end of the pitchover.
Yes, what is called "gravity turn" turns the velocity vector, but if the rocket didn't actively reorient itself (so as to keep in line with the velocity vector), gravity itself wouldn't rotate the rocket (change its attitude), because almost-homogeneous gravity field won't impart (meaningful) momentum. (Satellites can actually use it that way, but the time constants are substantial and not really relevant for an ascending rocket on a timescale of minutes.)
However, this is independent of the presence of the atmosphere. In real life, both scenarios need active control of attitude.
it feels to me that the fact that most of the weight is at the bottom of the rocket, ie near the pivot point, means that small or tall rocket are pretty much the same thing to land.
While the tall guy has more weight far from the pivot point, it also has more weight down (because more fuel to stop a heavier vehicle), more sensitivity to various winds and more physical tensions/torsions all along its body structure.
I'm not physicist/rocket scientist, so wondering if I'm missing something
> And the vertical landing architecture scales extraordinarily well. When you do a vertical landing, you’re solving the classic inverted pendulum problem, and the inverted pendulum problem gets a bit easier as the pendulum gets a bit bigger. Try balancing a pencil on the tip of your finger. Now try it with a broomstick. The broomstick is simpler because its greater moment of inertia makes it easier to balance.
They're specifically doing smaller rockets to tackle the inverted pendulum problem first, then they will scale up. They see that as the bigger challenge, and may greatly affect the design of larger orbital rockets which have a great deal of research available to draw from for other challenges they run into. In the article they say that one of their major solutions is a gimbaling engine, which I imagine is something you would have to design a larger rocket around, rather than add in after the fact.
>> I imagine is something you would have to design a larger rocket around, rather than add in after the fact.
Control authority. That is the measure of margin a system has over a feedback mechanism's (in case of a rocket: ability to accurately apply thrust in correct vector at required frequency) ability to dampen uncontrolled perturbations.
I'd bet you that SpaceX has just as thoroughly understood and tested their working margins on their landibg system's control authority as has Blue Origin. For this reason I don't believe Blue Origin has any technical advantage over SpaceX in the manner you imply they do.
This might be hubris, but there aren't too many things us humans don't understand about rocket design at this point. The last big one was the waterhammer effect in turbo pumps supplying rocket fuel.
Understanding 1st, 2nd, and 3rd harmonic vibrations in mechanical systems is standard practice in rocket and any other airframe design (Boeing airframes, missiles/rockets, etc). It's a solved problem.
If Bezos is hanging his hat on this argument, he's reached the limit of his omnipotence.
I'm not implying any advantage, only reiterating that they're starting small and building up. My reply was aimed at "I don't think the smaller booster is harder. It's almost by definition easier." which the article explicitly said the opposite of, which I then quoted.
I don't care if SpaceX or Blue Origin wind up on top, I don't own stock in either one, but I'm much more likely to trust the word of an actual certified rocket scientist than an unsourced HN comment.
This is amazing, and a pretty amazing feat that we are taking for granted. Space is super super tough, the complex coordination of manufacturing something like this is being totally written off by many, but I assure you it is non trivial.
A popular sentiment in that industry is that rocketry is like writing software composed of many modules and testing each module separately on mac, then deploying the entire build on linux. If it doesn't work, you don't just back out the conversion error or stray quotes you left in, your rocket explodes.
The engineering spend alone is massive, as is the damage to the company when a failure is syndicated across youtube. Taking big risks is something we should be promoting.
We are in a technological renaissance and it starts with lowering launch costs to achieve realtime LEO satellite blanketing and distributed communication channels to connect to the other fucking 3 billion people without internet. Bezos is accomplishing something great, and we don't need to qualify that statement.
He and Musk are definitively the Jobs and Gates of the 21st century if you want to use the obvious cliche.
What Gates did. What Jobs accomplished. It was pretty fucking powerful. Musk and Bezos are sort of doing that, except both are working in at least 3 industries at that same scale.
I wish Blue Origin, Sierra Nevada, Firefly and all the other people in new space well. Nano-sats will provide realtime insight to the earth, people will be able to own a satellite in ~5-10 years because of these advancements.
this is good for all of us, and the only negative thing to say about it is that for god sakes Jeff, that rocket does look a bit like a stubby penis.
1. popular sentiment in that industry is that rocketry is like writing software composed of many modules and testing each module separately on mac, then deploying the entire build on linux.
Musk always says the passing grade in rocketry is 100%. As there's no way to test a rocket fully except to actually launch it.
2. bit like a stubby penis lol
And that stubby thing shoots less powerfully than SpaceX.
I really don't see why these companies are competing. They are in totally different markets. Sure, there is some technological crossover in that they both use rockets, but this is like comparing a prius to a locomotive.
It sounds like Blue Origin rockets are only capable of sending payloads to space for just an instant, before gravity pulls them back down to earth. They're nowhere near close to capable of putting anything into orbit.
They're a smaller-scale test platform for figuring out how to do propulsive landing and re-use, similar to SpaceX's grasshopper rockets. Blue Origin is also developing an orbital rocket, which will hopefully be more impressive.
"Our vision: millions of people working and living in space"
When you have only a few seconds above the "official" space altitude on a parabolic trajectory, I wouldn't say" working and living in space", and specially not "millions" at the same time..
It is a bit disingenuous to imagine sustained life in space when we can barely live sustainably on the overwhelming majority of the surface of Earth. At least on Earth, we don't encounter the physical limitations that our bodies have when exposed to zero gravity, like loss of bone and muscle.
I think its great that New Shepard is coming along, I don't get how Bezos feels he is helping his cause when he says "people living and working in space." when he doesn't come close reaching orbit. The difference between an orbital mission and a sounding rocket.
Now, that he is getting closer to having tourist flights outside the atmosphere than Virgin Galactic? That is pretty cool and a fair comparison. Being able to out execute Burt Rutan? That counts for a lot, but don't try to compare yourself to SpaceX until you're putting things into LEO and getting back the hardware to use again.
Here is an animated video that shows what space tourism will be like. You will be in space for a few minutes. the view of the world from space will be amazing. plus you will be weightless. not sure how long you will be up there or the cost but it looks awesome.
This looks like a very complicated engineering achievement that undoubtedly will lead to advances in space travel and tourism.
That said, I didn't get to watch the launch and join in its success or failure, so I'm finding it difficult to actually care as much as other launches.
Is there a significance for ~100km? Is this, roughly speaking, space -- where the atmosphere is so thin to be almost negligible? Clearly atmosphere thins gradually so how do we define where space starts? Is the significance of ~100km something to do with the effects of gravity at that altitude from the Earth's surface? Does ~100km give you weightlessness? Or is Blue Origin going up to ~100km because it's a nice round number that is roughly (whatever that means) in space. But aren't kilometres completely arbitrary?
Also, can people please stop knocking Blue Origin. We get it at this point, okay? I'm a huge fan of SpaceX and Elon Musk but does Blue Origin have to lose for SpaceX to win? No. There's nothing in this post from Bezos bashing SpaceX as far as I can see. There's simply saying, look, we did it again with the same refurbished rocket. Good on them. May they do it again and again. And so may SpaceX. The next space race is on, happy days!
100km is the Kármán line, the generally accepted boundary of space. It's the point at which aeronautics become useless, as the atmosphere is too thin to support lift greater than your weight without going faster than orbital velocity. Contrary to popular belief, in Low Earth Orbit you're still very much in reach of the Earth's gravity; it's only about 10% less than the gravity on the surface.[2] The tricky part about orbit is moving sideways fast enough that you miss the ground.
So Blue Origin indeed got to space, landed and did it again. But it took a tiny fraction of the energy of the same feat for an orbital rocket (which is why SpaceX can only land its first stage).
Why then do astronauts on the ISS appear weightless? Do _not_ make me Google this :) And maybe we shouldn't call them astro- (suggesting star) nauts until they get to Sol and back. I kid! I guess in some sense we are all astronauts, man, on spaceship Earth. Seriously, maybe we should call them orbiternauts?
Something appears to be weightless when it is falling the same speed as everything around it. If you took a kitchen scale, taped a weight to the top, and dropped them, you'd notice it appears to have a weight of zero.
On the topic of falling, if you walk off a cliff, you fall to the base of the cliff. If you run, you fall farther way. The faster you go, the trajectory of your fall will be farther from the cliff. Now go really fast and you may fall miles away - but you'll be fighting air resistance and eventually slow down and hit the ground.
Above the Karman Line (62mi/100km up), the air is thin enough that there barely any air resistance. If you go fast up here, the air isn't there to slow you down. Gravity still pulls you back to earth though. [Blue Origin]
Now if you're above the atmosphere and going horizontally fast enough, the trajectory of your fall eventually overshoots the curvature of the earth. Follow that trajectory a quarter rotation around the earth -- you're still in space, you're still going fast, and you're still falling. You're in orbit. (SpaceX)
Since you're falling forever and the space station around you is also falling, you appear to be weightless in relation to the space station.
(The indie game Kerbal Space Program is a great way to play with/explore the concepts of orbital mechanics if you're intrigued.)
[Edit: For reference, the different in thrust needed to go straight up and coast to the Karman line compared to going up at an angle (spending more time traveling through the dense atmosphere) and establishing a horizontal speed of about 17,500 miles per hour is very big. I believe it's at least an order of magnitude though I don't have a citation for that number.]
> Above the Karman Line (62mi/100km up), the air is thin enough that there barely any air resistance. I
On the contrary, even at the altitude of the ISS there is sufficient atmosphere to reduce its velocity by around 5 metres / hour under normal conditions. Particle density at 400 km altitude is 10E+15 particles / cubic metre ( about a billion times less than at sea level ( but much more at times of Solar flaring.
The ISS makes a sonic boom which propagates to the ground, it's just incredibly weak.
Is Blue Origin landing a booster that SpaceX is letting crash? Would their forces combined result in total re-use? I'm not sure what all the parts and roles are. Sorry for the dumb question.
No. At one point, SpaceX has ambitions that they would recover the second stage of their Falcon 9, but then scrapped this idea as too difficult (until their next family of rockets). The reason is that the second stage is going much, much faster than the first stage, so it's a completely different problem to bring it back.
Blue Origins is not trying to get into orbit, and therefore is nowhere close to dealing with the issues that would confront a return of the Falcon 9 second stage. Quite the opposite; from a speed perspective, the Blue Origins rocket is more like an easy version of the already-recoverable Falcon 9 first stage (although as Bezos notes, some of the balancing issues may be harder by virtue of having a smaller moment arm).
I'd consider the goals similar. Both want to land and re-use orbital rocket boosters.
SpaceX landed an orbital booster, but they have yet to re-use that booster. I'm sure they would rather dissect that booster, since they have a factory and are continually building new ones.
Blue Origin landed a sub-orbital booster, and then re-used it. However, this booster is much smaller than what would be needed for orbit. So this rocket is more of a technology testbed (and potential fun ride). They'll have to build and design a whole new rocket in order to reach orbit - and they've already started doing so.
SpaceX is going 10x higher than Blue Origin. They can land on the ground, perfectly fine. They just haven't figured out how to do it on a moving barge, yet. Because launching from Houston means burning extra fuel to put the rocket over land. Fuel that could be used for boosting.
They aren't going ten times higher, or launching from Houston. They launch from Florida and California, they are building a launch site in Texas, but its not in Houston.
The Falcon 9 1st stage will get over twice as high on some flights. Then height it self isn't a big deal, it's the extra time in free fall speeding up before it hits the atmosphere.
The big difference, is that the Falcon 9 is heading east at 1.7km/s, carrying as much mass as a fully fueled BO rocket when it stages.
> They aren't going ten times higher, or launching from Houston.
They're definitely going 10x higher (significantly more, in fact). The SES-8 launch saw the SpaceX second stage hit 79,130km - 790x higher than Blue Origin's vehicle has hit.
To be fair, if you look at the video, you will see that they landed on the moving barge just fine. It was standing still on the platform, stable, with engine disabled.
Of the locks keeping the landing gear in place, 3 out of 4 succeeded. Whoops. Maybe they should simply switch to 5 or 6 landing gears. After all, they went for 9 engines and can boast multiple launches where one or two engines failed (including this latest one. One of the engines shit itself while the rocket was returning to the barge according to the twitter feed).
To be fair, "learned to land" and "did successful landing once" aren't the same things. Similarly, "USA landed on the moon" and "USA now has a capability to land on the Moon" are different things.
And SpaceX will get from here to there faster than the government.
No, staying standing up is a part of landing. We don't know if that gear failed because of shock forces in landing. "Figure out landing" means "make the rocket survive" not "get the toes touching the ground". I think SpaceX is doing more advanced work, has many more impressive successes than Blue Origin, but ignoring Blue Origin completely, I'm also not going to give SpaceX a pass on their objective failings.
SpaceX is reporting that one of the leg locks failed to deploy, IIRC due to ice buildup while passing through low-atmosphere moisture after reentry. From everything I've read, the landing had a more or less expected touchdown velocity and would have been successful had all four locks functioned as expected.
Actually, the altitude is quite irrelevant, the speed is the important part. Given a perfectly round planet with no atmosphere, you could even orbit 1m high.
Don't be pedantic. I'm sure assuming spherical cows we can make super efficient dairy farms. We don't have a perfectly round planet with no atmo. And we don't have rocket engineers who point rockets at the ground. Speed and altitude are practically the same thing.
No, they really aren't at all. The difference between a rocket that can reach 100km and 200km is tiny. The difference between one that can reach 100km, and a 100km orbit, is big.
Yeah, it's a bit like comparing stopping two cars running max speed into a parking spot with a wall in front: on car being a Bugatti Veyron and the other being a Smart TwoFour. It's certainly impressive to do it in the Smart, but it's rather much a different thing than the Bugatti.
Even that isn't a good analogy, because the speed difference between the Veyron and the TwoFour is only about 2.5x. So maybe if the 2nd car were my bicycle, then we'd be able to make a valid analogy.
This is awesome. A great compliment to the work SpaceX is doing. To put it in perspective this rocket went about 100x as high as an average international airline flight but would still need to go about 4000x as far to reach the moon. Not sure about the 3 mile per hour impact with the ground on my way home from work. I suppose with a nice soft seat it would be fine but by the time United Airlines gets done with it you'll be packed in like an NYC cross town bus with a seat just as hard.
> To put it in perspective this rocket went about 100x as high as an average international airline flight but would still need to go about 4000x as far to reach the moon.
The height at which airliners fly is about 10 km, and 100 km is only 10 times as high.
One would think that using fuel to touch-down slowly is wasting fuel since they could use some kind of capture scheme with a parachute instead. I've read many times that the weight of the fuel is a big problem in spacecraft.
I don't know why you're getting down votes, it's a reasonable question.
Most capture schemes require the rocket to survive structural forces it isn't designed to handle. Increasing its structural thrength would increase its weight. Spacex tried parachutes on early designs, but gave up on them. A parachute landing on the ground means impact forces, landing in the ocean means salt water corrosion. Also even parachutes have a cost in weight, including structural strengthening. SoaceX and Blue Origin have both looked at the various options, crunched the numbers and opted for propulsive landing.
The problem is that using a parachute means that--assuming your launching from Houston or Cape Canaveral--you're only going to be able to land in the ocean. With just a parachute, can you recover the booster and make it launchable in, say, a day? That's kind of the goal: to make rockets more like cars and less like soda cans, i.e. to reuse vs. recycle.
As mentioned numerous times, there's the whole "reaching space" vs "going into orbit" before landing.
More important to me is the fact that SpaceX is streaming its different tries in _live_, taking the risk of crashing the rocket out in the open. How many vehicles did BO lose before achieving a vertical landing ?
Oh, and what about the fact that they have total control on the location and time of the launch ? Meaning they basically control weather to an accuracy no one launching anything useful into space has. For example, last failed SpaceX landing was officially linked to fog icing the leg locks. That's not going to happen if you launch on a clear day from the desert.
These are more comparable to the Grasshoper tries than to anything SpaceX has done recently : no horizontal speed, full weather control, no reporting on failed attempts, very limited weight. Even the last grasshoper video seemed to have more side winds that had to be countered than this 100k altitude video.
Even the format of the video itself screams "vaporware" to me. It looks like a trailer for a bad action movie, where some spacey something goes to space, separates and lands back in 15 seconds. When the grasshoper videos left me in awe, looping over them 5 times in a row, the BO ones just make me feel like they sh/could end with some sexual innuendo over their big rocket