Comments by "ke6gwf - Ben Blackburn" (@ke6gwf) on "Scott Manley"
channel.
-
4
-
@steveaustin2686 you realize that when lunar Starship gets to lunar orbit, it will be met by a fuel tanker Starship to refuel it, so it can be reused, right?
So might as well send a Crew Starship as well, as long as you are building crew certified Starships.
Even if NASA doesn't trust them for earth launch or landing, you can shuttle from the moon to LEO, and then dock with Crew Dragon for launch and recovery.
So not really ANY need for SLS.
And, if NASA trusts Starship to land humans on the moon and then take off again, how is that any less risky than taking off from Florida with humans in it?
Once SpaceX got their foot in HLS, SLS is pretty much doomed once Starship starts flying successfully, because if NASA is trusting it on the moon, not much excuse not to trust it on the earth as well, especially after civilian crews start launching on it for space raves or whatever.
That's why they want to put as much money into SLS this budget cycle, because they know the flow of pork is threatened by SpaceX. Lol
4
-
3
-
3
-
3
-
@akyhne uh, no, SpaceX is known for being the only current US ride to space, for launching at an unprecedented cadence, for building giant shiny rockets bigger than any others ever built, and for doing it all at much lower prices than anyone else ever.
Oh, and for landing and reusing rockets.
The earth to earth simulation is NOT what they are known for, it's just a little side project, which by the way, the military is very interested in, and so we will probably see money put towards it.
3
-
3
-
3
-
@Tenkai917 as Scott pointed out, it looks like 3 drouge chutes deployed, (which are part of the parachute) and it almost looked at one point like there were 3 sets of shroud lines out, but then you ended up with only 2 parachutes.
If the drouge did in fact deploy, then it was a parachute failure, not just a failure to deploy.
Think of if you are skydiving, and you throw your drouge chute out, and your parachute either fails to come out because the drouge line breaks, or the parachute comes out but isn't properly attached to your harness and just falls away.
You deployed the parachute, but it failed.
So if 3 drouge chutes deployed but only 2 chutes opened, then it was a parachute failure.
3
-
What many are missing is that the "minor software issue" is actually a serious ground up design problem that needs to be completely redesigned with different assumptions and criteria.
They designed the system in a way where a single point of failure would cause the capsule to blindly do things regardless of any other inputs.
It was simply responding to a fixed sequence based on the clock, and that means that we won't find out what else has zero fault tolerance or error checking, until it's actually put to use.
I do industrial automation, so I am familiar with making large machines perform actions automatically, and you always want to verify your inputs and have some form of error checking or redundancy.
For instance, the easiest one. If the clock says 11, before you do the step for 11, you verify that the previous steps have been completed.
Or, before changing the orientation of the craft, you check the star trackers and GPS and verify where you are supposed to be with where you actually are.
You can also compare SECO/deployment with the download clock time and verify that they match the schedule.
But, just like with MCAS, it is a system with lots of power and no way to verify or error check what it's doing, so one input is all it needs to jump off the bridge blindly.
And you can say that it could be overridden by the crew and everything would be fine, but since they obviously failed in basic design and ground testing, designing a system that could fail so confidently, and not testing it adequately to discover this problem, but that is not a valid assumption, because the rest of the system is designed and tested by the same team, and so it would be surprising if this blind and Fail Dangerous system didn't have other similar flaws and bad assumptions and improperly tested aspects, that could have terrible consequences without a review as detailed as the MCAS is receiving.
3
-
3
-
The thing that you didn't talk about is thermal mass. Put the turkey inside a thick cast iron block, or maybe a liquid tank, and have a shutter that allows heat to reach the iron, or a tubes running the liquid through the heat shield, so that you heat up the thermal mass to 500 degrees or whatever, and then you stop adding heat
Then you can land the oven, and the cooking will continue while the recovery teams are tracking it down.
Have the capsule open up to stop the cooking when the BBQ thermo probe registers the correct internal temperature in the meat.
This simplifies things because you just have to plan for enough thermal mass for the correct cooking time, and then design the capsule and orbit to get the thermal mass up to the needed temperature, and since it would heat from the outside in, you could have the cast iron exposed directly to the plasma, and not overheat the turkey.
3
-
3
-
3
-
@thedarkknight1971 you seem to be falling into the fallacy that because YOU can't see the reason why something is done a particular way by people just as smart as you who have been working for years to research and design and test something, that they must be doing it wrong.
With your design, what happens when Mars dust is kicked up and fouls the launch rail sliders and it slows the rocket down from the grit? And you could add wheels and sealed bearings, but that adds weight and more failure points, what if a seal blows going in and out of atmospheres, and the bearing seizes or freezes, and how much clearance do you need so a pebble won't jam it entirely on launch?
The Yeet system can probably be enclosed until yeetage, and be made so that there is nothing for dust to bind up or clog.
And I am sure that they have considered all the possibilities, looked at the pros and cons, weighed the various options, and come up with the one they consider is the best.
But you haven't sat in on all their meetings or looked at their detailed size and mass calculations, you are just making an assumption about it all, and thinking that you are smarter than they are.
3
-
3
-
3
-
3
-
@MillionFoul you just described for me WHY they need to do actual testing, because the systems are so interrelated, actually testing different failure modes is the only way to verify that a new system is safe!
You are talking about a plane or rocket system like its a phone app, where you can just test it in the simulator, and then publish it, and then fix the bugs that show up, rather than testing it with different model phones and different OS versions.
It's fine for an app, not for a plane.
In addition, it was because of lack of testing and verification that they decided that MCAS wasn't a Catastrophic level system, because if they had looked at the more powerful version that shipped, they would have realized that it was capable of catastrophic failures.
But because they had very low levels of oversight and were happy to ship stuff with minimal verification and testing, it never got looked at after it was strengthened.
If they had been paying attention, they would have realized as soon as they discovered that they screwed up on the AOA disagree indicator, that the lack of it would leave the flight crew with no way to recognize an MCAS issue, especially considering that no one even knew MCAS existed, and someone would have realized that maybe they should alert the customers that the feature they were training for, didn't actually function.
But they decided that it wasn't needed, and so were going to include it quietly in a future update, which never came...
As to your claim that the crashes were mostly pilot error, you are assuming that the procedures and memory items are infallible and accurate, and they aren't.
They attempted to follow the runaway trim procedure, but they were unable to, because the manual trim wheels are not able to be cranked with the control surface at that high an angle, because the aerodynamic forces are too high to overcome manually, and they were too low altitude to be able to dive while they cranked it to take load off of it.
So when that didn't work, they re-engaged the trim cutouts, and were able to use the trim switch to recover.
Now, if Boeing/FAA had actually told anyone about MCAS, the procedure would be that if the AOA disagree indicator was on, and you had runaway trim, to use the yoke trim switches to get the proper trim, and then turn the trim cutout switches off.
And everything would have been fine.
But because they decided not to tell anyone, and instead rely on a 50 year old procedure that hadn't been tested under extreme conditions, and that made their untested software unable to be overridden, causing hundreds of deaths.
And claiming that the pilots didn't follow procedures that wouldn't work under those circumstances, in a failure mode that they had no training for, because a company shipped untested and unverified software without telling anyone, shows that you have bought into their culture, that not testing extensively is all right, because it costs too much to do proper testing.
And it's rich that you make this claim after all the other stuff has come out and the Max failures, both of internal and external oversight, and now seeing the same thing play out with Starliner, with major lack of testing, as well as lack of internal and oversight.
The whole system is broken if a company is this lax about testing their actual product, and the supposed oversight agency lets them do whatever they want, to save some time and money.
Hopefully this tragedy, and the Starliner comedy (since no one was on it) will get NASA to put Boeing back on the leash, and get the world airline regulators to get involved in making sure that the planes are safe, even if it costs more money.
3
-
@nicosmind3 , you have to remember that most of the fuel usage for a rocket launch is to accelerate it to orbital velocity, altitude is not the issue.
You can send a tiny rocket straight up into space with no orbital velocity, but it will then fall right back down because of gravity. If all you were trying to do was that, then yes, a mountain launch would get it a couple of miles closer, and thus less fuel needed, but when you consider all the fuel needed to haul it up the mountain, vs the amount of fuel needed to take the rocket 2 miles, it really isn't worth it.
Think of the difference between shooting a gun straight up in the air, so the bullet flies up, and then falls back down, vs spinning a bucket on the end of a rope.
It is getting the orbital velocity (the bucket on the rope, balanced forces of the velocity trying to send it away, and gravity pulling it back) that uses most of the fuel, which is why rockets tip over soon after leaving the pad, to begin pointing them around the globe, instead of away from it.
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
3
-
@tomhardy604 if it were a simple cone, rolling would be no problem, but it looks like it goes from a cylinder to a cone to a sphere, and so the transition areas at least would be compound curves.
Even then, getting precision panel size and shape would be difficult without some sort of punch press die process it would seem to me, because if you tried to laser cut it first, then roll it, you would get distortion and uneven edges from the rolling process, and then have to find some way to trim the edges to within spec, and since this is a BIG rocket, you might be talking about a few hundred panels per unit, and so I think since Elon likes automation, and because I suspect that the cost of making dies so that each panel is created in basically a single instant step is offset by avoiding the hand fitting that other methods would require, that it would be the natural choice, at least once he thinks he has the basic shape decided on.
And he may find another way to shape panels even better, like maybe hydroforming or drawing it in one giant piece, or maybe 2 clamshells or something. I am sure that he would love to find a way to make it seamless like the renderings lol
One way or another I am sure that he is going to figure out how to make it big, make it fast use robots, and most importantly, make it perfect and shiny!
Because, Elon
3
-
3
-
3
-
3
-
@engineer9673 I went back and looked at the pictures in high resolution, and I see no sign that any of the cylinders were extended beyond their limits, in fact the cylinder on the left is extended even further than the one on the bottom, and you can see that the left grid fin is within normal range of motion, so there is no reason to suspect that the cylinders were damaged.
It is also rare for a piston to break off a rod, since the entire system is designed to be stronger than the maximum forces applied, and the grid fins don't face very high forces.
I also suspect that the cylinders are also the mechanical limits of the grid fin travel, since the greatest force they will see is from the hydraulic cylinder action, and so there is no need for any other stops.
Generally hydraulic systems use the limits of the cylinder for the stops, unless there is some reason for another stop, but for a rotary device like this, you just make your cylinder the correct length for the desired throw, otherwise you are putting full hydraulic pressure against the linkages, and have to make them stronger to withstand it.
By using the cylinder as your limit, you ensure that the greatest force applied to the system is the aerodynamic forces created by the grid fin.
3
-
3
-
@A.Lifecraft it sounds like maybe you have also heard of trapping monkeys by putting chunks of salt etc into bulb shaped holes? Lol
The reasons that they don't just solder the wires around the edges is, 1, you would be relying entirely on the shear strength of the solder to hold the load, and 2, the cables are giant, and you would have to have a very large ring to be able to terminate every strand to the anchor ring.
Instead, the cable end is simply expanded, like the sticks on a witches broom, and unlike my analogy with your hand, the center is also full of strands, all evenly spaced apart.
So basically you are forming the end of the cable into a wedge shape, and then filling it in with the potting metal to hold that shape.
It doesn't rely on the sheer strength of the metal, which is why it's a tapered shape, so that the tension increases the gripping force on the wires much like a wedge and socket, but it's even stronger, because instead of simply using friction to hold the wires, it also uses the intermetallic bonds to make the wires become part of the wedge.
In addition, and very important for such a large cable, it evenly distributes the load across all the strands and compresses them all evenly.
In a wedge socket design, the friction is only on the outer strands, and it loads the core unevenly, while relying on bends in the cable to transfer force, leading to high stress points, cable, bundle, and strand deformation, and thus loss of strength.
This method protects each strand, does not require any bending or deformation, and equalizes the compression forces and friction and actual metallic bonds across all the wires.
3
-
3
-
3
-
3
-
3
-
2
-
2
-
@travcollier in other words, Peter is trying to make his decision not to copy SX sound reasonable. Same as ULA dismissing reusablity. But you have to look at two other factors as well. The reason Peter ate his hat is because he realized that if they were able to reuse rockets they could save money, by reducing the number of rockets they had to build. In other words, reusablity was cheaper than building a second factory.
So the recovery plan used a parachute and a helicopter, which is cheaper than a barge landing, for a tiny rocket.
It's not an option for SpaceX, because the Falcon 9 is MUCH too large to catch with a helicopter.
So Peter's new bigger rocket design is designed to do propulsive landing, and he is talking about how much money he saves by not using a barge, but at what cost?
SpaceX doesn't need a barge, they have RTLS pads right next to the launch pads, and they can save so much money. But at what cost?
RTLS takes away a lot of performance from the rocket, so less payload to orbit.
So while Peter might be saving money with no barge, he's also reducing the maximum payload he can carry for every flight, unless he goes full disposable.
So basically SpaceX has to look at each payload and flight and decide if it's cheaper to run the barge out there, or just dispose of the rocket.
And so far, between the actual cost savings of reuse, combined with the increased launch cadence allowed without building a new factory, the barges are a good investment.
But then, you have to remember that SpaceX wants to get away from the barges as well, which is where you need Starship, because it's large enough to RTLS with any size payload, so you are not limiting your largest payload by RTLS. You can launch an actual big yellow bulldozer to the moon with it!
And if someone made a large enough payload, they could do fully expendable and only be out a few million dollars in stainless steel lol
So Peter is talking up his personal choices, but not presenting the full picture, such as how much RTLS limits his payloads.
Falcon 9 ride share with that 3rd party custom space tug to deliver small sats to exact orbits will be cheaper than Neutron anyway, so it's only benefits are a little more scheduling customization.
And then Starship should be even cheaper still.
But, I suspect there are enough customers who don't want to give Elon money that Rocket Lab has a chance at survival lol
2
-
2
-
2
-
2
-
2
-
@Bourinos02 a single bus line was not an option at the Las Vegas convention center, because there is no room for it. Otherwise they would have simply bought a couple of busses.
And the reason so many casinos want the system to go to their casino is because traffic is already so bad that the busses that run the Strip can take an hour to get down it.
Even 30 mph is several times faster than the options.
You then compare some early concept art with the early prototype system, and don't see that the design matured since that early artwork, and also that the current system of human driven cars is only temporary.
As the demand increases, higher capacity pods specifically designed for tunnel operation will get built, but I don't expect to see that until after Giga Texas gets finished, since Fremont doesn't have the capacity to build any new designs.
And as the FSD software improves, it will be able to take a greater role in the driving.
And as longer straight tunnels are made, such as down the Strip, speeds can increase as well.
So all of your current complaints are that it's not all happening instantly right at the start, and so doesn't yet look like the end goal.
When Elon says "next year", he's saying that he thinks something can be achieved in that period of time, but he makes clear that he is speaking of the goals he has, and that there are often delays and setbacks.
Look at the Crew Dragon system. Years of delays, lots of "vapor ware" accusations, but now working beautifully.
Same with Starlink and Model 3 and countless other projects that he has worked on that were delayed and called impossible, and are now part of daily life.
And I was extrapolating that Starlink is probably over 2 hundred thousand users by now as they continue shipping dishes as fast as possible, but my point is that it's in daily use across the globe, so can't really call it vapor ware any more.
2
-
2
-
2
-
2