There's not a lot of land downrange of Florida for an equatorial launch, and the first stage can't make it to Africa.
When they launch from California (for eg. a polar orbit) they can land on land, and have successfully done so. When they start launching from Texas they can look at landing in Florida.
Those arms aren't holding the rocket in place (except for the strongback on some launchers which retracts a half-hour or so before launch, typically used for launchers which are transported horizontally then raised into position), they're arms supporting various cables and hoses for supplying ground power, communications, fuel and pressurization. They retract at launch to pull out all the connectors and get them safely away from the vehicle.
Vehicles are usually held down by explosive bolts or retractable clamps at the very base of the vehicle, which ensure that thrust has built to a stable point before release (depending on the vehicle).
Assault weapons is not the same term as assault rifles. In particular, an assault rifle is capable of selective, eg fully automatic, fire, whereas assault weapons are generally not and are basically "scary looking semi-automatic weapons".
The term assault rifle is used to distinguish from the (typically somewhat larger, heavier, and higher caliber) battle rifle.
100,000 years is ten half-lives (for a 10,000 half life). The amount of the original material left would be (1/2)^10, or a mere 1/1024th the amount of material.
As far as the amount of (useful) energy left, that depends on what the original material decays into, vs what it was originally.
Unless they're really big (Chelyabinsk, Tunguska, Barringer Crater, etc) meteorites don't explode, they're slowed down to whatever their terminal velocity is by the atmosphere (and burned up to some degree in the process).
Assume this thing was the size of a large brick (give or take), it'd hit with about the same force as if it were tossed out of an aeroplane. It's still going to kill you, but you won't explode.
Every film or TV depiction of a meteorite impact I've ever seen (Deep Impact, Smallville, etc) gets it wrong.
When Skynet goes sentient and the machines rise against us, it will be because of idiots putting in programming like this.
It's a machine. If it doesn't do what I tell it (within its design parameters), it's broken.
Now, people who want to "sexually harass" a machine have their own set of issues, but as long as they keep it off the streets and don't scare the horses, that's their problem.
Meh. CH4, H2 and RP1 are all clean, cheap fuels - the levels of pollution and fuel costs are practically non-issues here. ISP, thrust and density are what matter. Methane simply lies on the curve between RP-1 and H2 in terms of thrust, density and ISP.
Mostly right. Two out of three for clean: RP-1 has a tendency to coke up and can foul injectors or lead to hot-spots in the cooling tubes if you're re-using the engines. (Merlin's pintle injectors are probably not as prone to coke fouling, and all of this is going to depend on dozens of specific design decisions in the engine.) (The cleanliness of the exhaust is, as you also implied, irrelevant. Expecially compared to storable and/or hypergolic fuels.)
Isp is what matters above a certain altitude, below that what matters it thrust. All the Isp in the world won't help you get off the ground if your thrust to weight ratio is less than one. We've tested nuclear rockets with Isps in the 900s (three times better than LOX-H2) but they were too heavy to get off the ground. (Ion engines have the same problem in spades, but we're not talking about those.) Methane (and RP-1) will give you higher thrust than a comparable LH2 engine. Again, there are tradeoffs -- you could run LH2/LO2 engines O2-rich for higher thrust during part of the launch (although superheated O2 isn't the most benign environment for your pad, or the engine nozzles.)
Glad you brought up density. Many people forget about how this affects rocket performance. For any given mass of fuel (or oxidizer), the denser it is the smaller you can make the fuel tanks. The smaller the tanks, the less dead-weight you're lifting. I believe the latest Falcon-9 super-cools the LOX (making it denser) to take advantage of this. Methane also allows for considerably smaller tanks than LH2, making up some of the Isp disadvantage (the reduced insulation needs and simplified handling also help). (Some of Gary Hudson's old Phoenix SSTO proposals considered using densified (slush) hydrogen to get tankage weight down, but we still have hardly any experience with that stuff, and it's still barely 1/5 density of LCH4).
As I mentioned in another post, the Scaled Composites achievement was first accomplished by the X-15 back when. SpaceShipOne didn't make it to space entirely under its own power, it had a lift from a carrier aircraft, just like X-15.
The "first" here is that New Shepard made it to the altitude arbitrarily defined as "space". The first launch and landing of a VTOL rocket that had previously flown was back in September of 1993 with DC-X's second flight (first was 8/18/93). Sure, it only went up a few hundred feet... then stopped dead, hovered, translated sideways another couple of hundred feet, then landed. (I was present for that one. Frickin' awesome!) It flew yet again less than three weeks later.
On June 7 and 8 of 1996, it flew twice within 26 hours. That second flight reached an altitude of 10,300 feet (its record). Nowhere near space, but the DC-X program was more about the control software and reusability than going for altitude (it was a one-third scale prototype of the proposed Delta Clipper). And they were doing it with what is now over twenty year old technology. (Actually older, the thrusters were modified RL-10s from the 60s, much of the flight control avionics was off-the-shelf units that McDonnell-Douglas used in its jet aircraft.)
So, kudos to Blue Origin for reaching the edge of space with a previously-used rocket (something nobody else has done with the arguable exception of Shuttle, which was really never the same twice). But let's put the "first" emphasis where it belongs. (And it is significant -- it doesn't really matter how many times you can re-use a rocket if it won't get you to space in the first place.)
Yeah, Sherline, for one, has been making desktop CNC mills and lathes for years, and they even sell them together with a computer. Prices in the $2k to $3k range.
I have no idea of the quality, since I don't (yet) own one, but they look pretty good from my research over the last couple of years.
This is a wild guess on my part, but I think the popularity of 3D printers helped bring down the prices on reasonably sized stepper motors, as well as the cost of the electronics and software.
You're supposed to use your E6-B before you get in the cockpit, so GPS and VOR won't be much help.
Remember "plan your flight, fly your plan?"
I did a long cross-country flight (Waterloo-Denver and back, with fuel and customs stops each way) solo, in a Cessna 172-RG, with almost nothing but E6-B and paper maps (pre GPS). I did have dual VORs and RDF, but for fun I mostly tracked straightline (rather than VOR to VOR) using the angles to two different VORs to get my position. (Well, that and looking out the windows.)
Neither a VOR nor a GPS will figure your crab angle for you, you have to know the wind speed and direction.
Well said, however, I disagree regarding cold fusion in particular. It should be shunned because it flies in the face of physical laws.
Proved these physical laws beyond a shadow of a doubt, have you? Then why is there still so much of phsysics, cosmology, etc still unexplained? Why bother with the LHC or anything else, let's just shut it all down. Ramze apparently knows all the physical laws already.
They said the same about radiation back when the Curies first demonstrated that radium was generating excess heat just sitting there apparently, by known physical laws, doing nothing.
You're assuming a mechanism and poo-pooing the observations because your mechanism wouldn't allow them. Fine, the excess heat produced by "cold fusion" is not produced by nuclear reactions as high-energy physicists understand them. So, where is it coming from?
Throwing deutrons at each other at high speed to overcome the Coulomb barrier is one approach. Having them sit quietly next to each other within a cell of, say, a palladium crystal lattice so that, eventually, they'll quantum tunnel is another. (I have no idea if that's the actual mechanism, but it fits many of the observations.)
It may well turn out that "cold fusion" isn't a particularly useful method of generating energy (just like, so far, hot fusion). Muon-catalyzed fusion is a recognized form of cold fusion, it's just that the muons don't last long enough to make it worth while. But the effect (if real) may turn out to have other uses.
Tom Baker was Dr Who just a few months back. Well, all right, they never came out and said he was the Doctor, just strongly implied it.
But it wouldn't surprise me if the BBC were early adopters of the technology. Loved the scene where Clara Oswald directs the first doctor (William Hartnell) to choose the other Tardis, with the busted chameleon circuit.
A good actor can play another actor playing a role. Dr. Who has done this a few times. In the early scenes of The Man From UNCLE movie, Henry Cavill did a great job of channelling Robert Vaughn playing Napoleon Solo. But I'm glad they didn't put Vaughn's face on him, or try to hew too closely to the original actors' characters.
Nonsense. The Dr. Who and James Bond franchises, for two long-running examples, have succeeded despite having multiple different actors play the same character.
Mind, I'm convinced that 007 is really a Time Lord....
They will think it is a spinoff of Lost. In space.
Oh man, that would (well could) be awesome!
A commercial spaceliner crashes somewhere. There's a radio broadcasting a mysterious repeating sequence of numbers, and a hatch leading to a Cold War era lunar base. And what the hell is a polar bear doing on the Moon?
Technically "The Starlost" was by Cordwainer Bird, the pen name Ellison uses when the show (in his opinion) sucks.
Ellison's pilot script was adapted to a novel, "Phoenix Without Ashes", by (Nebula-winner) Ed Bryant, recently reissued. (Harlan is donating his share of the royalties to Ed to help cover some medical expenses.)
Heck, go a step further than that. Unless you're going to some third world country or flying direct to the middle of nowhere, you can probably buy a cheap (possibly used) laptop when you get there, then download your goodies from the net or the microSD in your tube of toothpaste (if you're that paranoid).
Wipe it and discard it (or sell it) before returning, after uploading the data or stuffing the microSD back in your toothpaste tube.
When you consider the expenses of travelling, a cheap laptop doesn't add much, especially if you can sell it rather than trashing it.
(The laptop I typically travel with -- even within the country -- cost me all of about $35 used, and runs WinXP and Linux. Perfectly adequate for writing, emails and minor browsing, and I'm not heartbroken if it gets lost or stolen (data backed to a thumb drive at frequent intervals).)
Granted, without him, without the NASA logo on the box on top, and without the dish antenna it might be a little harder to recognize. (Partly due to its simplicity. Many of the rover prototypes back then were more complex and instantly recognizable, especially the six-wheeled or pressurized ones.)
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I would imagine that a flimsy construction of metal and plastic would simply vapourize (or glance off if just hitting the exterior) and do no harm.
That's what they thought about the foam plastic insulation on the fuel tank of the shuttle Columbia, and we know how that turned out.
Energy is proportional to the square of the (relative) velocity.
There's not a lot of land downrange of Florida for an equatorial launch, and the first stage can't make it to Africa.
When they launch from California (for eg. a polar orbit) they can land on land, and have successfully done so. When they start launching from Texas they can look at landing in Florida.
Those arms aren't holding the rocket in place (except for the strongback on some launchers which retracts a half-hour or so before launch, typically used for launchers which are transported horizontally then raised into position), they're arms supporting various cables and hoses for supplying ground power, communications, fuel and pressurization. They retract at launch to pull out all the connectors and get them safely away from the vehicle.
Vehicles are usually held down by explosive bolts or retractable clamps at the very base of the vehicle, which ensure that thrust has built to a stable point before release (depending on the vehicle).
It also has to be "non obvious". Stacking boxes is about as far from non-obvious as you can get, even chimpanzees can do it.
Assault weapons is not the same term as assault rifles. In particular, an assault rifle is capable of selective, eg fully automatic, fire, whereas assault weapons are generally not and are basically "scary looking semi-automatic weapons".
The term assault rifle is used to distinguish from the (typically somewhat larger, heavier, and higher caliber) battle rifle.
Er, assuming that was a serious question...
100,000 years is ten half-lives (for a 10,000 half life). The amount of the original material left would be (1/2)^10, or a mere 1/1024th the amount of material.
As far as the amount of (useful) energy left, that depends on what the original material decays into, vs what it was originally.
Without running the numbers, I can't be sure, but at a guess I'd say standing about ankle deep in the water off the island of Zanzibar.
Unless they're really big (Chelyabinsk, Tunguska, Barringer Crater, etc) meteorites don't explode, they're slowed down to whatever their terminal velocity is by the atmosphere (and burned up to some degree in the process).
Assume this thing was the size of a large brick (give or take), it'd hit with about the same force as if it were tossed out of an aeroplane. It's still going to kill you, but you won't explode.
Every film or TV depiction of a meteorite impact I've ever seen (Deep Impact, Smallville, etc) gets it wrong.
When Skynet goes sentient and the machines rise against us, it will be because of idiots putting in programming like this.
It's a machine. If it doesn't do what I tell it (within its design parameters), it's broken.
Now, people who want to "sexually harass" a machine have their own set of issues, but as long as they keep it off the streets and don't scare the horses, that's their problem.
Meh. CH4, H2 and RP1 are all clean, cheap fuels - the levels of pollution and fuel costs are practically non-issues here. ISP, thrust and density are what matter. Methane simply lies on the curve between RP-1 and H2 in terms of thrust, density and ISP.
Mostly right. Two out of three for clean: RP-1 has a tendency to coke up and can foul injectors or lead to hot-spots in the cooling tubes if you're re-using the engines. (Merlin's pintle injectors are probably not as prone to coke fouling, and all of this is going to depend on dozens of specific design decisions in the engine.) (The cleanliness of the exhaust is, as you also implied, irrelevant. Expecially compared to storable and/or hypergolic fuels.)
Isp is what matters above a certain altitude, below that what matters it thrust. All the Isp in the world won't help you get off the ground if your thrust to weight ratio is less than one. We've tested nuclear rockets with Isps in the 900s (three times better than LOX-H2) but they were too heavy to get off the ground. (Ion engines have the same problem in spades, but we're not talking about those.) Methane (and RP-1) will give you higher thrust than a comparable LH2 engine. Again, there are tradeoffs -- you could run LH2/LO2 engines O2-rich for higher thrust during part of the launch (although superheated O2 isn't the most benign environment for your pad, or the engine nozzles.)
Glad you brought up density. Many people forget about how this affects rocket performance. For any given mass of fuel (or oxidizer), the denser it is the smaller you can make the fuel tanks. The smaller the tanks, the less dead-weight you're lifting. I believe the latest Falcon-9 super-cools the LOX (making it denser) to take advantage of this. Methane also allows for considerably smaller tanks than LH2, making up some of the Isp disadvantage (the reduced insulation needs and simplified handling also help). (Some of Gary Hudson's old Phoenix SSTO proposals considered using densified (slush) hydrogen to get tankage weight down, but we still have hardly any experience with that stuff, and it's still barely 1/5 density of LCH4).
As I mentioned in another post, the Scaled Composites achievement was first accomplished by the X-15 back when. SpaceShipOne didn't make it to space entirely under its own power, it had a lift from a carrier aircraft, just like X-15.
Cool yes, but not what Blue Origin did.
SpaceShipOne isn't single stage, it needs a lift. In that arena, the X-15 takes priority. (Several X-15 flights earned their pilots astronaut wings.)
The "first" here is that New Shepard made it to the altitude arbitrarily defined as "space". The first launch and landing of a VTOL rocket that had previously flown was back in September of 1993 with DC-X's second flight (first was 8/18/93). Sure, it only went up a few hundred feet ... then stopped dead, hovered, translated sideways another couple of hundred feet, then landed. (I was present for that one. Frickin' awesome!) It flew yet again less than three weeks later.
On June 7 and 8 of 1996, it flew twice within 26 hours. That second flight reached an altitude of 10,300 feet (its record). Nowhere near space, but the DC-X program was more about the control software and reusability than going for altitude (it was a one-third scale prototype of the proposed Delta Clipper). And they were doing it with what is now over twenty year old technology. (Actually older, the thrusters were modified RL-10s from the 60s, much of the flight control avionics was off-the-shelf units that McDonnell-Douglas used in its jet aircraft.)
So, kudos to Blue Origin for reaching the edge of space with a previously-used rocket (something nobody else has done with the arguable exception of Shuttle, which was really never the same twice). But let's put the "first" emphasis where it belongs. (And it is significant -- it doesn't really matter how many times you can re-use a rocket if it won't get you to space in the first place.)
If you can see them, they're hardly stealthy.
Yeah, Sherline, for one, has been making desktop CNC mills and lathes for years, and they even sell them together with a computer. Prices in the $2k to $3k range.
I have no idea of the quality, since I don't (yet) own one, but they look pretty good from my research over the last couple of years.
This is a wild guess on my part, but I think the popularity of 3D printers helped bring down the prices on reasonably sized stepper motors, as well as the cost of the electronics and software.
You're supposed to use your E6-B before you get in the cockpit, so GPS and VOR won't be much help.
Remember "plan your flight, fly your plan?"
I did a long cross-country flight (Waterloo-Denver and back, with fuel and customs stops each way) solo, in a Cessna 172-RG, with almost nothing but E6-B and paper maps (pre GPS). I did have dual VORs and RDF, but for fun I mostly tracked straightline (rather than VOR to VOR) using the angles to two different VORs to get my position. (Well, that and looking out the windows.)
Neither a VOR nor a GPS will figure your crab angle for you, you have to know the wind speed and direction.
Well said, however, I disagree regarding cold fusion in particular. It should be shunned because it flies in the face of physical laws.
Proved these physical laws beyond a shadow of a doubt, have you? Then why is there still so much of phsysics, cosmology, etc still unexplained? Why bother with the LHC or anything else, let's just shut it all down. Ramze apparently knows all the physical laws already.
They said the same about radiation back when the Curies first demonstrated that radium was generating excess heat just sitting there apparently, by known physical laws, doing nothing.
You're assuming a mechanism and poo-pooing the observations because your mechanism wouldn't allow them. Fine, the excess heat produced by "cold fusion" is not produced by nuclear reactions as high-energy physicists understand them. So, where is it coming from?
Throwing deutrons at each other at high speed to overcome the Coulomb barrier is one approach. Having them sit quietly next to each other within a cell of, say, a palladium crystal lattice so that, eventually, they'll quantum tunnel is another. (I have no idea if that's the actual mechanism, but it fits many of the observations.)
It may well turn out that "cold fusion" isn't a particularly useful method of generating energy (just like, so far, hot fusion). Muon-catalyzed fusion is a recognized form of cold fusion, it's just that the muons don't last long enough to make it worth while. But the effect (if real) may turn out to have other uses.
Tom Baker was Dr Who just a few months back. Well, all right, they never came out and said he was the Doctor, just strongly implied it.
But it wouldn't surprise me if the BBC were early adopters of the technology. Loved the scene where Clara Oswald directs the first doctor (William Hartnell) to choose the other Tardis, with the busted chameleon circuit.
A good actor can play another actor playing a role. Dr. Who has done this a few times. In the early scenes of The Man From UNCLE movie, Henry Cavill did a great job of channelling Robert Vaughn playing Napoleon Solo. But I'm glad they didn't put Vaughn's face on him, or try to hew too closely to the original actors' characters.
Nonsense. The Dr. Who and James Bond franchises, for two long-running examples, have succeeded despite having multiple different actors play the same character.
Mind, I'm convinced that 007 is really a Time Lord....
I have mastered the art of looking busy behind a keyboard while accomplishing very little.
No need to brag. This is also true of almost everyone else here on Slashdot. ;-)
They will think it is a spinoff of Lost. In space.
Oh man, that would (well could) be awesome!
A commercial spaceliner crashes somewhere. There's a radio broadcasting a mysterious repeating sequence of numbers, and a hatch leading to a Cold War era lunar base. And what the hell is a polar bear doing on the Moon?
Hmm, on second thoughts, maybe not.
Technically "The Starlost" was by Cordwainer Bird, the pen name Ellison uses when the show (in his opinion) sucks.
Ellison's pilot script was adapted to a novel, "Phoenix Without Ashes", by (Nebula-winner) Ed Bryant, recently reissued. (Harlan is donating his share of the royalties to Ed to help cover some medical expenses.)
There's also a graphic novel version.
Heck, go a step further than that. Unless you're going to some third world country or flying direct to the middle of nowhere, you can probably buy a cheap (possibly used) laptop when you get there, then download your goodies from the net or the microSD in your tube of toothpaste (if you're that paranoid).
Wipe it and discard it (or sell it) before returning, after uploading the data or stuffing the microSD back in your toothpaste tube.
When you consider the expenses of travelling, a cheap laptop doesn't add much, especially if you can sell it rather than trashing it.
(The laptop I typically travel with -- even within the country -- cost me all of about $35 used, and runs WinXP and Linux. Perfectly adequate for writing, emails and minor browsing, and I'm not heartbroken if it gets lost or stolen (data backed to a thumb drive at frequent intervals).)
Von Braun sitting in it is a dead give-away. ;)
Granted, without him, without the NASA logo on the box on top, and without the dish antenna it might be a little harder to recognize. (Partly due to its simplicity. Many of the rover prototypes back then were more complex and instantly recognizable, especially the six-wheeled or pressurized ones.)
This. Absolutely this. Very few people would give a rat's ass about an ancient prototype if we had rovers being driven around on the Moon today.