Of course, we know they're not going to be doing that either. Even ignoring the continual delays, SLS is simply an impractical launch vehicle. Way too expensive per launch, and they'll never have enough launches to refine it.
NASA needs to accept that it's not going to be a launch supplier, and switch to what it does best: R&D and exploration missions. And the new launch environment should be embraced. Think of what can be done when launch costs are much less than spacecraft development costs: suddenly you have a much stronger incentive to mass-produce spacecraft designs, since the incremental cost becomes so much less than the single-unit cost. Picture the era where we don't launch, say, 1 Dawn spacecraft, we launch a hundred of them, each to different bodies. We don't launch 1 Mars rover, we launch a couple dozen, each to different parts of Mars. Etc.
I bet Silicor really regrets not building their new Iceland plant (they backed out because the price of polysilicon just couldn't support it). They had a really cool technology; I wouldn't support the building of an old-fashioned silicon producer near me (we have a couple in the country; they're pretty terrible), but I supported them. Basically it's based around aluminum alloying; they dissolve impure silicon in aluminum, then cool it (settling it out as flakes, which they skim), then etching away residual aluminum from the flakes with hydrochloric acid. It's then re-melted one more time to separate out any residual aluminum. In addition to the silicon, the process byproducts are silicon-rich aluminum alloys (which are worth more than the original aluminum) and polyaluminum chloride (used in water treatment).
Yes, but if you want that much electricity, you have to have huge, heavy radiators. Nuclear thermal avoids that because the heat goes out the nozzle. The downside is that it's not as high specific impulse as lower thrust propulsion methods that deal with magnetically confined plasmas and electric power sources.
Even if you don't discard the LOX tanks and do it as a SSTO, the mass fraction is still greatly improved versus a pure hydrogen NTR. And even in the portion of the flight where you're burning LOX with the hot H2, it's significantly higher performance than a regular hydrolox engine, because the hydrogen has already taken on a lot of energy; if I recall the numbers correctly, designs predict somewhere around 550 sec sea level.
Adding an afterburner doesn't increase the total system mass much, but greatly increases thrust for early in the flight when you really need it. And in many ways, you're facing a much easier task than a regular hydrolox engine. Your hydrogen is gaseous and has enough energy to vaporize the LOX, so you're dealing with gas phase combustion, as well as self ignition.
It's interesting thinking about how far you can take nuclear thermal designs. Picture, for example, the afterburner case, with a fission fragment reactor as the heater. You can transition all the way from super high thrust for liftoff and atmospheric flight, to moderate thrust / high ISP for attaining orbit and performing orbital maneuvers, all the way to ISPs in the hundreds of thousands via direct fission fragment propulsion (note: requires large radiators). A single system could provide you access to every flight mode needed for missions ranging from the surface Earth out to the Oort Cloud and even potentially beyond - as well as effectively unlimited onboard power. And you can refill it anywhere you can get water; given the very high temperatures capable in the core, the primary loop should readily function for thermolysis (it happens on its own at those temperatures), with hydrogen-selective membranes leading to the hydrogen tank and a chiller for liquefaction (needed regardless to deal with boiloff).
More to the point, the GP's comments on hydrogen embrittlement are actually rather amusing. You know the primary means to reverse the damage from hydrogen embrittlement? Annealing (heating the material to elevated temperatures).;) It doesn't even take a very high temperature.
It won't lift from the planet. The gravity is too high, and the total mass is too high.
Even old (let alone modern) NTR rockets had quite positive T/W ratios on Earth - let alone Venus where gravity is lower. I don't know what type of rocket you're picturing, but it's not nuclear thermal.
And on Venus it is worse - the acid atmosphere would damage the engine.
1) The conditions on Venus are often overstated. There's only a few to a few dozen mg per m3 H2SO4 in Venus's "habitable zone". OSHA allows workers to breathe up to 1 mg per m3 for an entire 8 hour shift. Admittedly the acid mists on Venus are a higher concentration than on Earth, but it's important to realize that we're talking vog here, not an "acid bath"
2) Exposure to an acid VOG is nothing compared to the conditions inside an operating rocket engine in terms of corrosiveness.
Unfortunately (orrather fortunately) we'll almost certainly be sliding backwards on a a TRL perspective. There have been a lot of major improvements in NTR design since then - not just for higher peak ISPs, but in particular to deal with the poor T/W of previous designs. The first big improvement was the LOX afterburner concept, wherein you burn the hot hydrogen with LOX early in the flight fie greatly augmented thrust, then revert to pure H2. Since then a lot of designs have also called for bringing atmospheric air into the mix, ranging from simple ram air thrust augmentation all the way up to designs with nuclear thermal-driven compressors and NTR scramjets.
Its hard to say at what point the added complexity ceases to pay off, but at the very least, the afterburner offers a huge leap forward at little cost. And of course you want modern ISPs too. To a point ; some of the more exotic reactor designs can theoretically provide crazy ISPs, but they do so by keeping the hydrogen hotter than the rest of the reactor with tricks like fission fragment reactors, which are anything but mature. Then again, if the craft could also double as a pure fission fragment rocket as well, that would certainly be pretty keen...
Nuclear thermal is particularly interesting for Venus ascent stages. It lets you do them single stage, and while you essentially have to use hydrogen, it doesn't take that much. It reduces the habitat lift requirements dramatically; while the dry mass is high, the vastly reduced propellant requirements outweigh that many times over. It aslo makes it plausible to launch to high elliptical orbits rather than LVO; this cuts the Dv requirements down on the interplanetary transfer stage significantly, meaning either faster transfers or larger payloads. Some NTR designs offer hover capability, which would enable (effectively) limitless, propellentless hover time during docking without needing a balloon stage. And lastly, since a Venus ascent stage would never operate anywhere even near Earth, NIMBY concerns would be greatly reduced.
The problem is that decent EVs aren't just made off the shelf. They're designed from the ground-up as EVs, and involve a lot of high-tech products as a significant portion of both their part counts and value. India is the last place you would look to to try to source parts for a modern EV.
When it comes to EVs, India has brought these problems on themselves. They insist on cars sold locally being made with at least 30% locally manufactured components, a protectionist policy that has been very successful at keeping foreign-made EVs out. But local EV manufacture in India is in its infancy.
That's actually part of the problem with LIDAR - it's superb at seeing obstacles (in good weather conditions, at least), but it provides you with no information about what you're seeing. Everything is an obstacle.
Radar on the other hand wouldn't even see the trash bag. But a bit of aluminum foil will give a huge blazing return.
Camera vision systems might recognize a trash bag as a trash bag, but only if they were trained to and are proven good at their task.
You really need a combination of sensors, and some very challenging software behind it that is trained to deal with a huge variety of edge cases.
To be actually fair, Tesla continually does precisely the opposite, and there is essentially zero confusion among actual Tesla owners about what it's actually capable of. Heck, if you take your hands off the wheel for too long too many times in a row, the vehicle will revoke your autopilot privileges until the next time you charge up.
EAP is in a state at this point where its limitations are obvious enough that it's hard to become too complacent. The problem arises when autopilot-style systems get good enough that you don't see its flaws very often, and so drivers become complacent - and then when something actually does go wrong, they're not ready to deal with it.
That said, what we have that a car doesn't is a brain that automatically fixes photogrammetric stitching errors based on the logic of "that doesn't make sense" - whether something "makes sense" or not being an AI-hard problem. So one tries to compensate for this on vehicles with better sensors than human beings have.
Lidar provides a superb data stream when conditions are right, but it's too problematic. You're not going to put awkward, draggy, ugly domes on top of everyone's cars. They're way too expensive, and even if the price can come down, they're way too prone to adverse weather. Wherein, what, do you tell people that the car can't drive? Or that they have to?
I think the future on this front is time-of-flight cameras as a supplemental datastream to multi-input driving systems. A company like Tesla could simply swap out their existing cameras for time-of-flight ones and get a LIDAR-like datastream, which they can plug in as a better alternative to their current photogrammetry + radar streams when weather allows for it, and otherwise fall back on photogrammetry + radar. Time-of-flight cameras still yield the same sort of visual information as regular cameras, but can also record the length of time between a IR pulse is issued and when different parts of the CMOS/CCD register the reflection, and thus produce a high resolution "LIDAR" map instantaneously with each pulse throughout the camera's entire field of view. Because they're manufactured with traditional semiconductor methods, in theory they should be little more expensive to produce when in mass production than conventional cameras.
Either way, though, you still need conventional cameras for object identification, for seeing colours, and a whole host of other things. A z depth map on its own isn't enough.
I remember way back when that there was a site that plugged itself as a "Toyota Simulator" (seems to be down now). When you went to the site, it was nothing but a looping video of a car driving way too fast down a road and a person screaming.;)
Ah, I should have tacitly assumed that you meant the much heavier 3-series Gran Turismo that only exists on paper
Are you blind? I wrote, right above: "The 3-series comparable to the Model 3 is the 330i, not the 318i"
Wow, a website ran by a Tesla fanboy with the aim of positively influencing his investments in Tesla thinks Tesla's new product is better than another product from another manufacturer.
It's a feature-by-feature comparison. If you disagree, point out where it's wrong. Ad hominem is not a valid method of debate.
Yes, I foolishly assumed you'd compare to the right 3-series, aka a car of equivalent size. Stupid me. I should have known that of course you'd deliberately pick a smaller car to try to bias the comparison. Shock of all shock, if you make a car smaller, it gets lighter!
The Tesla Model 3 isn't comparable to any BMW 3-series.
I am looking it up and getting different numbers than you. So rather than insisting that the numbers I'm finding are wrong, how about you back up your claim?
As for performance, we're comparing to the lowest powered Model 3. If it can't even keep up with that (and it's way behind), it makes one wonder if it should even be considered in the same class.
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Of course, we know they're not going to be doing that either. Even ignoring the continual delays, SLS is simply an impractical launch vehicle. Way too expensive per launch, and they'll never have enough launches to refine it.
NASA needs to accept that it's not going to be a launch supplier, and switch to what it does best: R&D and exploration missions. And the new launch environment should be embraced. Think of what can be done when launch costs are much less than spacecraft development costs: suddenly you have a much stronger incentive to mass-produce spacecraft designs, since the incremental cost becomes so much less than the single-unit cost. Picture the era where we don't launch, say, 1 Dawn spacecraft, we launch a hundred of them, each to different bodies. We don't launch 1 Mars rover, we launch a couple dozen, each to different parts of Mars. Etc.
Loosened pesticide regulations have a negative impact on native beelion populations.
You do realize that we're talking about the core of a nuclear thermal rocket correct? It's not exactly a winter wonderland in there.
I bet Silicor really regrets not building their new Iceland plant (they backed out because the price of polysilicon just couldn't support it). They had a really cool technology; I wouldn't support the building of an old-fashioned silicon producer near me (we have a couple in the country; they're pretty terrible), but I supported them. Basically it's based around aluminum alloying; they dissolve impure silicon in aluminum, then cool it (settling it out as flakes, which they skim), then etching away residual aluminum from the flakes with hydrochloric acid. It's then re-melted one more time to separate out any residual aluminum. In addition to the silicon, the process byproducts are silicon-rich aluminum alloys (which are worth more than the original aluminum) and polyaluminum chloride (used in water treatment).
Yes, but if you want that much electricity, you have to have huge, heavy radiators. Nuclear thermal avoids that because the heat goes out the nozzle. The downside is that it's not as high specific impulse as lower thrust propulsion methods that deal with magnetically confined plasmas and electric power sources.
Even if you don't discard the LOX tanks and do it as a SSTO, the mass fraction is still greatly improved versus a pure hydrogen NTR. And even in the portion of the flight where you're burning LOX with the hot H2, it's significantly higher performance than a regular hydrolox engine, because the hydrogen has already taken on a lot of energy; if I recall the numbers correctly, designs predict somewhere around 550 sec sea level.
Adding an afterburner doesn't increase the total system mass much, but greatly increases thrust for early in the flight when you really need it. And in many ways, you're facing a much easier task than a regular hydrolox engine. Your hydrogen is gaseous and has enough energy to vaporize the LOX, so you're dealing with gas phase combustion, as well as self ignition.
It's interesting thinking about how far you can take nuclear thermal designs. Picture, for example, the afterburner case, with a fission fragment reactor as the heater. You can transition all the way from super high thrust for liftoff and atmospheric flight, to moderate thrust / high ISP for attaining orbit and performing orbital maneuvers, all the way to ISPs in the hundreds of thousands via direct fission fragment propulsion (note: requires large radiators). A single system could provide you access to every flight mode needed for missions ranging from the surface Earth out to the Oort Cloud and even potentially beyond - as well as effectively unlimited onboard power. And you can refill it anywhere you can get water; given the very high temperatures capable in the core, the primary loop should readily function for thermolysis (it happens on its own at those temperatures), with hydrogen-selective membranes leading to the hydrogen tank and a chiller for liquefaction (needed regardless to deal with boiloff).
More to the point, the GP's comments on hydrogen embrittlement are actually rather amusing. You know the primary means to reverse the damage from hydrogen embrittlement? Annealing (heating the material to elevated temperatures). ;) It doesn't even take a very high temperature.
Even old (let alone modern) NTR rockets had quite positive T/W ratios on Earth - let alone Venus where gravity is lower. I don't know what type of rocket you're picturing, but it's not nuclear thermal.
1) The conditions on Venus are often overstated. There's only a few to a few dozen mg per m3 H2SO4 in Venus's "habitable zone". OSHA allows workers to breathe up to 1 mg per m3 for an entire 8 hour shift. Admittedly the acid mists on Venus are a higher concentration than on Earth, but it's important to realize that we're talking vog here, not an "acid bath"
2) Exposure to an acid VOG is nothing compared to the conditions inside an operating rocket engine in terms of corrosiveness.
Sigh... it's built around a corruption either way, so you might as well.
(It's "Ásgarðr" - the "Garden of the Æsir"; the Æsir are the gods in the main Norse pantheon)
Unfortunately (orrather fortunately) we'll almost certainly be sliding backwards on a a TRL perspective. There have been a lot of major improvements in NTR design since then - not just for higher peak ISPs, but in particular to deal with the poor T/W of previous designs. The first big improvement was the LOX afterburner concept, wherein you burn the hot hydrogen with LOX early in the flight fie greatly augmented thrust, then revert to pure H2. Since then a lot of designs have also called for bringing atmospheric air into the mix, ranging from simple ram air thrust augmentation all the way up to designs with nuclear thermal-driven compressors and NTR scramjets.
Its hard to say at what point the added complexity ceases to pay off, but at the very least, the afterburner offers a huge leap forward at little cost. And of course you want modern ISPs too. To a point ; some of the more exotic reactor designs can theoretically provide crazy ISPs, but they do so by keeping the hydrogen hotter than the rest of the reactor with tricks like fission fragment reactors, which are anything but mature. Then again, if the craft could also double as a pure fission fragment rocket as well, that would certainly be pretty keen...
Nuclear thermal is particularly interesting for Venus ascent stages. It lets you do them single stage, and while you essentially have to use hydrogen, it doesn't take that much. It reduces the habitat lift requirements dramatically; while the dry mass is high, the vastly reduced propellant requirements outweigh that many times over. It aslo makes it plausible to launch to high elliptical orbits rather than LVO; this cuts the Dv requirements down on the interplanetary transfer stage significantly, meaning either faster transfers or larger payloads. Some NTR designs offer hover capability, which would enable (effectively) limitless, propellentless hover time during docking without needing a balloon stage. And lastly, since a Venus ascent stage would never operate anywhere even near Earth, NIMBY concerns would be greatly reduced.
It's an OLED screen; in a year or two, they'll all be able to get green lines just by telling the phone to draw white ones. ;)
The problem is that decent EVs aren't just made off the shelf. They're designed from the ground-up as EVs, and involve a lot of high-tech products as a significant portion of both their part counts and value. India is the last place you would look to to try to source parts for a modern EV.
When it comes to EVs, India has brought these problems on themselves. They insist on cars sold locally being made with at least 30% locally manufactured components, a protectionist policy that has been very successful at keeping foreign-made EVs out. But local EV manufacture in India is in its infancy.
That's actually part of the problem with LIDAR - it's superb at seeing obstacles (in good weather conditions, at least), but it provides you with no information about what you're seeing. Everything is an obstacle.
Radar on the other hand wouldn't even see the trash bag. But a bit of aluminum foil will give a huge blazing return.
Camera vision systems might recognize a trash bag as a trash bag, but only if they were trained to and are proven good at their task.
You really need a combination of sensors, and some very challenging software behind it that is trained to deal with a huge variety of edge cases.
Ahem.
I can only guess that those other 2% have never actually used the thing or known anyone who has.
To be actually fair, Tesla continually does precisely the opposite, and there is essentially zero confusion among actual Tesla owners about what it's actually capable of. Heck, if you take your hands off the wheel for too long too many times in a row, the vehicle will revoke your autopilot privileges until the next time you charge up.
EAP is in a state at this point where its limitations are obvious enough that it's hard to become too complacent. The problem arises when autopilot-style systems get good enough that you don't see its flaws very often, and so drivers become complacent - and then when something actually does go wrong, they're not ready to deal with it.
12 ultrasonic sensors on Model 3.
That said, what we have that a car doesn't is a brain that automatically fixes photogrammetric stitching errors based on the logic of "that doesn't make sense" - whether something "makes sense" or not being an AI-hard problem. So one tries to compensate for this on vehicles with better sensors than human beings have.
Lidar provides a superb data stream when conditions are right, but it's too problematic. You're not going to put awkward, draggy, ugly domes on top of everyone's cars. They're way too expensive, and even if the price can come down, they're way too prone to adverse weather. Wherein, what, do you tell people that the car can't drive? Or that they have to?
I think the future on this front is time-of-flight cameras as a supplemental datastream to multi-input driving systems. A company like Tesla could simply swap out their existing cameras for time-of-flight ones and get a LIDAR-like datastream, which they can plug in as a better alternative to their current photogrammetry + radar streams when weather allows for it, and otherwise fall back on photogrammetry + radar. Time-of-flight cameras still yield the same sort of visual information as regular cameras, but can also record the length of time between a IR pulse is issued and when different parts of the CMOS/CCD register the reflection, and thus produce a high resolution "LIDAR" map instantaneously with each pulse throughout the camera's entire field of view. Because they're manufactured with traditional semiconductor methods, in theory they should be little more expensive to produce when in mass production than conventional cameras.
Either way, though, you still need conventional cameras for object identification, for seeing colours, and a whole host of other things. A z depth map on its own isn't enough.
I remember way back when that there was a site that plugged itself as a "Toyota Simulator" (seems to be down now). When you went to the site, it was nothing but a looping video of a car driving way too fast down a road and a person screaming. ;)
Well, then parents should just turn to shows that they already know only feature wholesome content, such as LazyTown.
What the hell is wrong with you that you can't provide an actual link to information that you're claiming contradicts what I wrote?
Are you blind? I wrote, right above: "The 3-series comparable to the Model 3 is the 330i, not the 318i"
It's a feature-by-feature comparison. If you disagree, point out where it's wrong. Ad hominem is not a valid method of debate.
Yes, I foolishly assumed you'd compare to the right 3-series, aka a car of equivalent size. Stupid me. I should have known that of course you'd deliberately pick a smaller car to try to bias the comparison. Shock of all shock, if you make a car smaller, it gets lighter!
Try again.
Again, you failed to back up your claim. Try linking to actual numbers, as I have.
I am looking it up and getting different numbers than you. So rather than insisting that the numbers I'm finding are wrong, how about you back up your claim?
As for performance, we're comparing to the lowest powered Model 3. If it can't even keep up with that (and it's way behind), it makes one wonder if it should even be considered in the same class.