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 International Skeptics Forum More on Musk's Mars Mission Machinations

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 15th October 2017, 10:55 AM #361 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by steenkh Not everybody think that Musk's Hyperloop is such a failure: Virgin Hyperloop One: Branson Boosts Elon Musk's Futuristic Tube Transport Branson is a newspaper editor. He knows nothing about the technology. If you really want to discuss this, we can. Explain why it would make more sense to have a vacuum filled tube than to fill it with hydrogen gas. The equation for drag is dynamic pressure x surface area x coefficient of drag. Assuming that the size and shape don't change and therefore the surface area and coefficient stay constant, that only leaves dynamic pressure. This is equivalent to kinetic energy and is similarly related to mass x velocity squared. So, if you have a target velocity then all you can do is reduce the mass of the fluid you are traveling through. Nitrogen weighs 14 while hydrogen weighs 1. So, you get 1/14th of the mass if you fill the tube with hydrogen. That's 1/14th the drag. This is about the same as the drag at 57,000 feet altitude. This tube wouldn't need to be massive since it isn't a pressure vessel. You would have to stay under transonic since shock waves would fatigue the container walls. Last edited by barehl; 15th October 2017 at 11:00 AM.
 15th October 2017, 11:05 AM #362 fagin Philosopher     Join Date: Aug 2007 Location: As far away from casebro as possible. Posts: 5,818 Branson is a newspaper editor? That's news to me. __________________ There is no secret ingredient - Kung Fu Panda
 15th October 2017, 11:05 AM #363 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by smartcooky resupplying and restaffing the ISS, and eventually commercial aviation. Well, for resupplying ISS wouldn't that require a vessel considerably larger than Dragon? Or are you talking about using his 85 tonne ship? Wouldn't that get you back in the same boat as the Space Shuttle with a lot of wasted payload? I'm not understanding the commercial aviation part.
 15th October 2017, 11:17 AM #364 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by fagin Branson is a newspaper editor? That's news to me. I guess you would call it a magazine rather than a newspaper and he was also the publisher. Virgin.com. As a 15-year-old student, I was disgruntled with the archaic school practices of the day, and was vocal about it. My headmaster suggested that I air my views in the school magazine, but Jonny Gems and I wanted to set up an alternative magazine with a fresh attitude. Gradually the idea of an interschool publication, Student magazine, was hatched. I also wrote to WHSmith asking whether they would be prepared to stock the magazine. Thus, with contributors, advertisers, distributors and costs all in place – at least on paper – I had written my first business plan.It was from this that he got enough money to start the fledgling label, Virgin Records. They got lucky with Tubular Bells and it became a big label. Last edited by barehl; 15th October 2017 at 11:20 AM.
 15th October 2017, 11:27 AM #365 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by GlennB p.s. while thinking about an 'ice' landing it occurred to me that the engines of these ships are going to blast the surface pretty hard on landing and takeoff. Did your forum discuss how big a hole it might be? On a related note, it seems to me that the whole eventual fleet of 6 ships had better not get too close, as there's going to be some serious debris flying around in that low g and thin atmosphere. Oh please God, tell me you're not a "where's the blast crater?" Apollo denier! __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 15th October 2017, 12:05 PM #367 GlennB Loggerheaded, earth-vexing fustilarian     Join Date: Sep 2006 Location: Pie City, Arcadia Posts: 22,838 Originally Posted by smartcooky Oh please God, tell me you're not a "where's the blast crater?" Apollo denier! I am not an Apollo denier In fact I was somewhat gutted to be off on a school field activities trip in S Wales at the time of Apollo 11. However, given the mass, approach and power of the two crafts they are far from the same. Look at a (relatively feeble) Falcon 9 landing and the 'activity' down on the clean, bespoke landing pad. And that's little more than dust being blown around. Picture that for a BFR on a rocky, sandy surface with low g and next-to-zero atmosphere. Would you fancy a BFR landing 50m away from your equipment on the surface of Mars? No, no you wouldn't. 200? 500? When the fleet is spread out over a circle measuring a few km, for safety, transport becomes an important factor. Also, please stop looking for the killer rhetorical blow and actually discuss the subject, eh? __________________ "Even a broken clock is right twice a day. 9/11 truth is a clock with no hands." - Beachnut Last edited by GlennB; 15th October 2017 at 12:09 PM.
 15th October 2017, 12:11 PM #368 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by barehl Well, for resupplying ISS wouldn't that require a vessel considerably larger than Dragon? Or are you talking about using his 85 tonne ship? Wouldn't that get you back in the same boat as the Space Shuttle with a lot of wasted payload? You're still thinking old school, like GlennB - one launch to do one task. What is to stop them doing more than one task - resupplying and taking astronauts to ISS, bringing astronauts & experiments back from ISS, taking some fare-paying passengers, and launching a couple of communications satellites. Originally Posted by barehl I'm not understanding the commercial aviation part. Then you have not watched the presentation that led to this thread. https://www.youtube.com/watch?v=tdUX3ypDVwI __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 15th October 2017, 12:21 PM #369 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by GlennB I am not an Apollo denier In fact I was somewhat gutted to be off on a school field activities trip in S Wales at the time of Apollo 11. However, given the mass, approach and power of the two crafts they are far from the same. Look at a (relatively feeble) Falcon 9 landing and the 'activity' down on the clean, bespoke landing pad. And that's little more than dust being blown around. Picture that for a BFR on a rocky, sandy surface with low g and next-to-zero atmosphere. Would you fancy a BFR landing 50m away from your equipment on the surface of Mars? No, no you wouldn't. 200? 500? When the fleet is spread out over a circle measuring a few km, for safety, transport becomes an important factor. Have you ever researched why there is no blast crater? I have. Weakness of the LM descent engine is only part of the reason, a relatively small part. Here's a clue for you Originally Posted by GlennB Also, please stop looking for the killer rhetorical blow and actually discuss the subject, eh? I don't have to look for them. You keep presenting them on a silver platter __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 15th October 2017, 10:29 PM #370 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by smartcooky Have you ever researched why there is no blast crater? I have. Weakness of the LM descent engine is only part of the reason, a relatively small part. Here's a clue for you https://www.dropbox.com/s/yu0vqivhqj...aunch.jpg?dl=1 https://www.dropbox.com/s/vik380tntr...-high.jpg?dl=1 I don't have to look for them. You keep presenting them on a silver platter You could also gimbal the landing engines to their max for landing. You'll have some cosine losses, but ejecta would be directed away from the ship, reducing the fod danger. And I'll repeat that the engines are designed to be able to ingest a nut and continue working. The only problem with landing FOD that I see is potential damage to the vacuum bells and can be replaced in situ. __________________ This signature is intended to imitate people.
 15th October 2017, 11:19 PM #371 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 FCC permit application for antenna testing for satellite broadband: https://www.geekwire.com/2017/spacex...-seattle-area/ SpaceX have a launch permit (1390) for November 10 that is being kept quiet - no official payload announced. Rumors are that the codename for this launch is Zuma. Make it that what you will __________________ This signature is intended to imitate people.
 15th October 2017, 11:45 PM #372 GlennB Loggerheaded, earth-vexing fustilarian     Join Date: Sep 2006 Location: Pie City, Arcadia Posts: 22,838 Originally Posted by Octavo You could also gimbal the landing engines to their max for landing. You'll have some cosine losses, but ejecta would be directed away from the ship, reducing the fod danger. I wasn't talking about ejecta damaging the ship itself. The ejecta thought was to do with neighbouring ships and equipment, and the minimum area over which the final fleet can be spread. Anyway, it's pretty tiresome to have every branch of the subject result in getting hit with personal gibes, so I'll bow out. If you get to Mars please don't forget to send a postcard. Cheers! __________________ "Even a broken clock is right twice a day. 9/11 truth is a clock with no hands." - Beachnut
 15th October 2017, 11:59 PM #373 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by GlennB Anyway, it's pretty tiresome to have every branch of the subject result in getting hit with personal gibes, so I'll bow out. If you get to Mars please don't forget to send a postcard. Cheers! Perhaps you misread something in my last couple of posts? I certainly didn't intend any attacks on you. As for ejecta hitting other spaceships, I think there are several options. Firstly it's likely that the first two unmanned ships will never leave. They will most likely be used as initial habitation and spare parts for emergency situations and they should probably be landed a good 200 - 500 m apart. If they land with ablative shields facing each other, I think the risk of serious damage is extremely low. I am concerned about the first manned ship. Either the unmanned precursor missions need to robotically pour a landing pad, or Musk believes landing/taking off from an unprepared spot wont be a problem. I don't know how would have determined that. __________________ This signature is intended to imitate people.
 16th October 2017, 12:04 AM #374 GlennB Loggerheaded, earth-vexing fustilarian     Join Date: Sep 2006 Location: Pie City, Arcadia Posts: 22,838 Originally Posted by Octavo Perhaps you misread something in my last couple of posts? I certainly didn't intend any attacks on you. As for ejecta hitting other spaceships, I think there are several options. Firstly it's likely that the first two unmanned ships will never leave. They will most likely be used as initial habitation and spare parts for emergency situations and they should probably be landed a good 200 - 500 m apart. If they land with ablative shields facing each other, I think the risk of serious damage is extremely low. I am concerned about the first manned ship. Either the unmanned precursor missions need to robotically pour a landing pad, or Musk believes landing/taking off from an unprepared spot wont be a problem. I don't know how would have determined that. Final comment - sorry, I wasn't talking about you just then. __________________ "Even a broken clock is right twice a day. 9/11 truth is a clock with no hands." - Beachnut
 16th October 2017, 02:18 AM #375 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by barehl Well, for resupplying ISS wouldn't that require a vessel considerably larger than Dragon? Or are you talking about using his 85 tonne ship? Wouldn't that get you back in the same boat as the Space Shuttle with a lot of wasted payload? I'm not understanding the commercial aviation part. Dragon 2 is capable of carrying 7 astros and several tons of supplies in the unpressurised trunk to the ISS. It was specifically developed to NASA contract specs, in order to resupply the station. Dragon 1 (the currently flying incarnation) is not man-rated and is only allowed to carry pressurized and unpressurized cargo. Despite Dragon 1, not being man-rated, it has flown live mice to the ISS on several flights and even brought live mice back to Earth in it's last mission. CRS-13, the next cargo resupply flight is due to launch no earlier than 28 November. Dragon 2 is tentatively slated to fly a demonstration mission no earlier than March 2018. The 85ton Spaceship (or BFS - big falcon spaceship) is technically capable of resupplying the ISS and yes, it is massive overkill in that role. However, overkill doesn't matter if flying BFR+BFS is cheaper than flying F9+Dragon. That's what rapid, gas-n-go reusability gets you. The STS was designed to be rapidly reusable too, but as it turns out, using super-lightweight silica tiles for heat-shielding because you're mass-constrained and throwing away 50% of the launch vehicle each time turned out to be major obstacles to rapid reuse. SpaceX believes that they can solve this problem with newer materials, 3D additive manufacturing and some seriously advanced CFD simulations.* They've managed to show ULA and the rest of the Oldspace industry up by first demonstrating booster landings and now by flying payloads on reused boosters. A Block 5 version of the first stage is due out by the end of the year. SpaceX claims this will be the final version of F9, with all new design work being focused on the BFR/BFS system. Block 5 is being designed so that it can be reused up to 10 times without the need for major refurbishment. With Block 5, SpaceX hopes to be able to recover the payload fairings as well as the first stage. The fairings are large carbon-composite structures worth \$6 million per pair. SpaceX has been experimenting with fairing recovery for several months now and appear to have recovered one half the fairing in at least some of the last few missions. The fairing recovery method is not known in detail, but informed speculation from examining launch footage indicates some cold-gas nitrogen thrusters to maintain reentry orientation and a parafoil for a guided landing. Speculation is that the parafoil will guide the fairing directly onto a floating bouncy castle, to avoid salt-water contamination. * https://www.nextplatform.com/2015/03...homegrown-cfd/ __________________ This signature is intended to imitate people.
 16th October 2017, 02:27 AM #376 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by barehl Explain why it would make more sense to have a vacuum filled tube than to fill it with hydrogen gas. The equation for drag is dynamic pressure x surface area x coefficient of drag. Assuming that the size and shape don't change and therefore the surface area and coefficient stay constant, that only leaves dynamic pressure. This is equivalent to kinetic energy and is similarly related to mass x velocity squared. So, if you have a target velocity then all you can do is reduce the mass of the fluid you are traveling through. Nitrogen weighs 14 while hydrogen weighs 1. So, you get 1/14th of the mass if you fill the tube with hydrogen. That's 1/14th the drag. This is about the same as the drag at 57,000 feet altitude. This tube wouldn't need to be massive since it isn't a pressure vessel. You would have to stay under transonic since shock waves would fatigue the container walls. Unless I'm misreading you, didn't you just answer your own question? The closer you can get the tube to a full vacuum, the less drag you would have, no? Unless you are trying to escape having to build a pressure vessel? This brings us neatly on to The Boring Company. I think Musk realised fairly soon after announcing his Hyperloop idea that building a 500km steel pressure vessel and somehow still dealing with thermal expansion was probably a killer design flaw. Tunnels have to be waterproof though... which means they're also by default pressure vessels and I don't think thermal expansion is much of an issue at -20m. __________________ This signature is intended to imitate people.
 16th October 2017, 02:50 AM #377 ceptimus puzzler   Join Date: May 2003 Posts: 5,292 The problems I see with Hyperloop, apart from the astronomical cost, are the complexity of the airlocks at the stations, the difficulties of carrying out maintenance inside the tunnels, the failure modes when a tunnel wall or airlock is breached by human error / fault / earthquake / other natural disaster / terrorism. There are smaller problems too like needing to have turntables or large track loops at the termini to turn the vehicles around for their return journey. It seems to me that Branson and others are investing more for the publicity value of the hype and maybe returns from a resulting investment bubble rather than any reasonable expectation that a working transport system will be completed during their lifetimes.
 16th October 2017, 03:00 AM #378 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by ceptimus The problems I see with Hyperloop, apart from the astronomical cost, are the complexity of the airlocks at the stations, the difficulties of carrying out maintenance inside the tunnels, the failure modes when a tunnel wall or airlock is breached by human error / fault / earthquake / other natural disaster / terrorism. I'm not super-clued up on Hyperloop, but I thought they had some complex venting system to avoid airlocks. I'm not sure - it's not really that interesting to me. Originally Posted by ceptimus It seems to me that Branson and others are investing more for the publicity value of the hype and maybe returns from a resulting investment bubble rather than any reasonable expectation that a working transport system will be completed during their lifetimes. A fair comment I think. His investment in Virgin Galactic has the same feel to it. The UAE is interested in trying to prove the system between Dubai and Abu Dhabi by throwing some money at feasability studies. It's a good place to start I'd have though. Absolutely flat, straight shot, no pesky zoning issues or NIMBY groups. Thermal expansion will be a significant issue though. I'll be interested to see what comes from this study... https://cleantechnica.com/2016/11/10...potential-uae/ __________________ This signature is intended to imitate people.
 16th October 2017, 03:02 AM #379 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by Octavo You could also gimbal the landing engines to their max for landing. You'll have some cosine losses, but ejecta would be directed away from the ship, reducing the fod danger. And I'll repeat that the engines are designed to be able to ingest a nut and continue working. The only problem with landing FOD that I see is potential damage to the vacuum bells and can be replaced in situ. Well the primary reason why the LM didn't dig out a blast crater when it landed (and the reason why BFS won't either) is because of the distribution of the exhaust pressure in a vacuum (or in the case of BFS on Mars, in a very thin atmosphere). The two photos of Apollo launches I posted were at low altitude and then high altitude where the air is thinner. The exhaust plume is contained when the atmosphere is more dense. You see the same effect in a Falcon launch too, just prior to staging when the octaweb configuration of the outer eight Merlin engines is very apparent. In the extremely low density of Mars' atmosphere, the exhaust plume of BFS will be so wide that the thrust in kgm2 will be very low per unit area. It will probably push surface debris sideways to some extent, but it won't be digging out any craters. Just as an aside, that sideways pushing of material also accounts for another favourite gripe from Apollo Hoax believers... "why were the upper surfaces of the LM landing pads virtually devoid of lunar dust, they should be covered in it"... ... the answer is the same. The unrestricted extent of the exhaust plume due to the lack of atmosphere literally blasted away any dust that might have settled there, coupled with the fact that even the tiniest speck of dust would fly on a ballistic trajectory in the vacuum. __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 16th October 2017, 03:14 AM #380 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by Octavo With Block 5, SpaceX hopes to be able to recover the payload fairings as well as the first stage. The fairings are large carbon-composite structures worth \$6 million per pair. SpaceX has been experimenting with fairing recovery for several months now and appear to have recovered one half the fairing in at least some of the last few missions. The fairing recovery method is not known in detail, but informed speculation from examining launch footage indicates some cold-gas nitrogen thrusters to maintain reentry orientation and a parafoil for a guided landing. Speculation is that the parafoil will guide the fairing directly onto a floating bouncy castle, to avoid salt-water contamination. * https://www.nextplatform.com/2015/03...homegrown-cfd/ Yet another thing they have been told is impossible... "Impossible is just a big word thrown around by small men who find it easier to live in the world they've been given than to explore the power they have to change it. Impossible is not a fact. It's an opinion. Impossible is not a declaration. It's a dare. Impossible is potential. Impossible is temporary. Impossible is nothing." - Muhammad Ali __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 16th October 2017, 03:18 AM #381 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by smartcooky Yet another thing they have been told is impossible... With regard to recovering the fairings, I don't understand why ULA didn't start trying this from the 70's already. The fairing is staged ASAP, and recovery doesn't require nearly the sort of investment or complexity that booster recovery does __________________ This signature is intended to imitate people.
 16th October 2017, 06:17 PM #382 Beelzebuddy Philosopher     Join Date: Jun 2010 Posts: 6,071 Originally Posted by Octavo With regard to recovering the fairings, I don't understand why ULA didn't start trying this from the 70's already. The fairing is staged ASAP, and recovery doesn't require nearly the sort of investment or complexity that booster recovery does Cost-plus contracts. They were never paid to investigate reuse.
 16th October 2017, 06:40 PM #383 theprestige Penultimate Amazing   Join Date: Aug 2007 Posts: 27,069 Originally Posted by Octavo I am concerned about the first manned ship. Either the unmanned precursor missions need to robotically pour a landing pad, or Musk believes landing/taking off from an unprepared spot wont be a problem. I don't know how would have determined that. Test flights are not a mystery, you know. After figuring out the Apollo mission profile, NASA put a lot of effort into researching the exact details and constraints of the lunar landing. They surveyed landing sites, studied the landings of unmanned probes, and flew landing simulators here on earth. These activities known to us.
 16th October 2017, 08:56 PM #384 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by theprestige Test flights are not a mystery, you know. After figuring out the Apollo mission profile, NASA put a lot of effort into researching the exact details and constraints of the lunar landing. They surveyed landing sites, studied the landings of unmanned probes, and flew landing simulators here on earth. These activities known to us. Apollo didn't put the heatshield that keeps you+ship intact during reentry on the lunar lander though, but I take your point - it's not like it hasn't been done before. __________________ This signature is intended to imitate people.
 17th October 2017, 05:27 AM #385 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 According to the Reddit AMA recently, the design shown at IAC2017 has already changed. Notably a 3rd sea-level Raptor has been added to the BFS. Given that they plan to start building STA's in 6 - 9 months, this worries me. I would have thought a 6 - 9 month timeframe for STA's would mean they were deep into final design review. Adding another engine doesn't sound much to me like "final" design review __________________ This signature is intended to imitate people.
 17th October 2017, 08:37 AM #386 stevea Master Poster   Join Date: Aug 2007 Posts: 2,053 Why send hominids so early ? Wouldn't it make more sense to send some form of robots to excavate tunnels needed, create better landing platforms, create any needed fuel supply, food supply ?
 17th October 2017, 11:07 AM #387 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by stevea Why send hominids so early ? Wouldn't it make more sense to send some form of robots to excavate tunnels needed, create better landing platforms, create any needed fuel supply, food supply ? I think Musk wants people to get excited about Mars and to start thinking seriously about how to live on it. Robots are more practical, but nothing beats having a human there from a psychological point of view. Musk missed the Apollo landings and I think he feels his generation was short-changed. We were supposed to have the Shuttle, but it turned into an expensive boondoggle. Maybe he just wants to create his own apollo moment. __________________ This signature is intended to imitate people.
 17th October 2017, 12:57 PM #388 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by Octavo I think Musk wants people to get excited about Mars and to start thinking seriously about how to live on it. Robots are more practical, but nothing beats having a human there from a psychological point of view. Not to mention, of course that an actual human scientist can do in a day what a robot takes weeks or months to achieve. How many robot rovers would it have taken over how many months, to achieve what Harrison Schmitt achieved in an afternoon on the moon; the discovery of something that "looked interesting" (the orange soil) which changed the whole way we looked at the formation of the solar system. This is what a human scientist can do that a machine cannot... use its vast experience to say "that formation looks interesting, I think I'll stroll over there and have a look" As I have pointed out before. the two Apollo 17 astronauts drove and walked around for more kilometres in their three lunar surface EVAs totalling 22 hours, 3 minutes and 57 seconds than the MSL (Curiosity) rover has in six years on Mars. From a scientific perspective, a robot rover is a very poor substitute for sending an actual human scientist. __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 17th October 2017, 01:01 PM #389 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by smartcooky "He knows nothing about the technology.", well I challenge that statement. How do you know this? Have you spoken to him, or questioned him about it? Do you have evidence that he knows nothing about the technology? He has dyslexia and dropped out of school at the age of 16. He has started not a few, not dozens, but hundreds of business ventures. When exactly do you imagine that he has had time to study science, engineering, and technology? This isn't a credible suggestion.
 17th October 2017, 01:07 PM #390 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by smartcooky You're still thinking old school, like GlennB - one launch to do one task. No, I'm just going by what Musk has said. Quote: What is to stop them doing more than one task - resupplying and taking astronauts to ISS, bringing astronauts & experiments back from ISS, taking some fare-paying passengers, and launching a couple of communications satellites. That doesn't get around the point that the ship weighs 85 tons. Are you now claiming another vessel that Musk hasn't mentioned? Quote: Then you have not watched the presentation that led to this thread. https://www.youtube.com/watch?v=tdUX3ypDVwI Yes, I've seen it. The part you are referring to starts at 40:00. That idea is pure nonsense.
 17th October 2017, 01:23 PM #391 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by Octavo Unless I'm misreading you, didn't you just answer your own question? The closer you can get the tube to a full vacuum, the less drag you would have, no? No, not when the cost of the pressure vessel vastly exceeds the cost of the train. Quote: Unless you are trying to escape having to build a pressure vessel? Yes. Quote: This brings us neatly on to The Boring Company. I think Musk realised fairly soon after announcing his Hyperloop idea that building a 500km steel pressure vessel and somehow still dealing with thermal expansion was probably a killer design flaw. Which would be why his test tube was a steel vessel? I'm not following the logic. Quote: Tunnels have to be waterproof though... which means they're also by default pressure vessels and I don't think thermal expansion is much of an issue at -20m. So you think he can bore a 350 mile tunnel from San Francisco to Los Angeles? And you assume that the rock strata and liner will hold a vacuum? If that were true then wouldn't they have saved a ton of money at CERN? Instead they have a pressure vessel. Maybe they should have talked to Musk.
 17th October 2017, 01:26 PM #392 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by stevea Why send hominids so early ? Wouldn't it make more sense to send some form of robots to excavate tunnels needed, create better landing platforms, create any needed fuel supply, food supply ? Musk can't get his "self-driving" car to work; how is he going to build a robot?
 17th October 2017, 01:29 PM #393 barehl Master Poster     Join Date: Jul 2013 Posts: 2,646 Originally Posted by smartcooky How many robot rovers would it have taken over how many months, to achieve what Harrison Schmitt achieved in an afternoon on the moon I think Stevea was talking about human-form robots.
 17th October 2017, 02:20 PM #394 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by barehl He has dyslexia and dropped out of school at the age of 16. He has started not a few, not dozens, but hundreds of business ventures. When exactly do you imagine that he has had time to study science, engineering, and technology? This isn't a credible suggestion. Simply not having any formal training in a subject does not mean you "know nothing" about it. I am a formally trained and qualified Aeronautical Engineer (MEng) specializing in Avionics Maintenance and Technology. So, I know about these subjects. However, I also have a keen interest in Music (no formal training), Astronomy (no formal training), Aerospace (no formal training), Sports Journalism (no formal training) and Photography (no formal training). Just because I have no formal training in any of the last five subjects doesn't mean that I "know nothing" about them. Had you said "He has no formal training in the fields related to this technology" I'd have no quibbles, but your statement "He knows nothing about the technology" is unverifiable nonsense. PS: Albert Einstein, Ann Bancroft, Jack Horner, Michael Faraday, Pierre Curie, Carol Greider, Fred Epstein, Harvey Cushing and Peter Lovatt all have or had dyslexia. The condition is a hurdle, but it isn't a block to achievement in science and technology __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not. Last edited by smartcooky; 17th October 2017 at 03:30 PM.
 17th October 2017, 02:23 PM #395 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by barehl I think Stevea was talking about human-form robots. If that's the case then I'll double down on what I said. We are nowhere near (not within 50/100 years) of having "Asimov" type robots/androids that can do everything humans can do. __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 17th October 2017, 02:56 PM #396 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by barehl That doesn't get around the point that the ship weighs 85 tons. Yes... and? Are you claiming that an 85 tonne spacecraft could not be put into orbit (careful now!). Originally Posted by barehl Are you now claiming another vessel that Musk hasn't mentioned? What is it about doing more than one task with one launch that escapes you? To make it really, kindergarten clear for you... resupplying and taking astronauts to ISS could be done using the same ship on the same launch, as bringing astronauts & experiments back from ISS, and using the same ship on the same launch, taking some fare-paying passengers, and using the same ship on the same launch, launching a couple of communications satellites. The new BFR will deliver a 50 tonne payload to LEO... that could be four, 5 tonne satellites, 20 tons of supplies for ISS, two crew members for exchange and half a dozen fare paying passengers... all in ONE BFS, with payload capacity to spare. Originally Posted by barehl Yes, I've seen it. The part you are referring to starts at 40:00. That idea is pure nonsense. A broad statement. Explain in detail why this is not possible. __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not.
 17th October 2017, 03:52 PM #397 theprestige Penultimate Amazing   Join Date: Aug 2007 Posts: 27,069 Originally Posted by smartcooky Not to mention, of course that an actual human scientist can do in a day what a robot takes weeks or months to achieve. A human can do it at vastly greater risk and expense. Now that we have robots, "because science!" is no longer the compelling argument you seem to think it is.
 17th October 2017, 05:47 PM #398 smartcooky Philosopher     Join Date: Oct 2012 Location: Nelson, New Zealand Posts: 8,225 Originally Posted by theprestige A human can do it at vastly greater risk and expense. Now that we have robots, "because science!" is no longer the compelling argument you seem to think it is. It doesn't mean that robots should replace humans in space exploration You want to talk about Musk anticipating technology that isn't here yet, well robots that are capable of doing everything that a human scientist can do are a lot further away than a manned mars landing at least 100 years IMO. Developing such robots has already cost many billions and we're not even close to being ready to eve try to get to the first rung on the ladder. Never send a machine to do a man's job. __________________ ► 9/11 was a terrorist attack by Islamic extremists; 12 Apollo astronauts really did walk on the Moon; JFK was assassinated by Lee Harvey Oswald,who acted alone. ► Never underestimate the power of the Internet to lend unwarranted credibility to the colossally misinformed. - Jay Utah ► Heisenberg's Law - The weirdness of the Universe is inversely proportional to the scale at which you observe it, or not. Last edited by smartcooky; 17th October 2017 at 05:51 PM.
 17th October 2017, 06:08 PM #399 theprestige Penultimate Amazing   Join Date: Aug 2007 Posts: 27,069 Originally Posted by smartcooky It doesn't mean that robots should replace humans in space exploration You want to talk about Musk anticipating technology that isn't here yet, well robots that are capable of doing everything that a human scientist can do are a lot further away than a manned mars landing at least 100 years IMO. Developing such robots has already cost many billions and we're not even close to being ready to eve try to get to the first rung on the ladder. Never send a machine to do a man's job. Robots have already replaced humans in space exploration. Robots are already doing science on Mars, and throughout the solar system. A human could do the same amount of science as Curiosity in a fraction of the time, but the cost would be astronomical, and the risk unacceptable. That's why Curiosity is on Mars right now: To actually get science done. And robots will only get better. Every technological advance that makes humans more efficient and surviveable makes robots commensurately more cost effective as well. A human's job is to go in harm's way to save lives. For everything else? There's robots.
 17th October 2017, 11:17 PM #400 Octavo Illuminator     Join Date: Jun 2007 Location: South Africa Posts: 3,439 Originally Posted by barehl Which would be why his test tube was a steel vessel? I'm not following the logic. He built the scaled test track in order to be able to host university engineering challenges. This is also a useful way of identifying promising hires for his companies. Shrewd. Originally Posted by barehl So you think he can bore a 350 mile tunnel from San Francisco to Los Angeles? And you assume that the rock strata and liner will hold a vacuum? If that were true then wouldn't they have saved a ton of money at CERN? Instead they have a pressure vessel. Maybe they should have talked to Musk. Probably they should have. A waterproofed tunnel is not magic, it's a well understood technology. It's been held back by the slow pace of tunneling. Musk seeks to change that. Originally Posted by barehl Musk can't get his "self-driving" car to work; how is he going to build a robot? Evidence please? Originally Posted by theprestige A human could do the same amount of science as Curiosity in a fraction of the time, but the cost would be astronomical, and the risk unacceptable. That's why Curiosity is on Mars right now: To actually get science done. In that case, can we agree that if you could lower the risk and the cost both, to some arbitrary level (that we may disagree on), that humans+robots would be a superior solution than sending only robots? Musk for now is concentrating on lowering the cost to the point where sending humans becomes if not economically viable, then at least within the means of large corporates and national space agencies. He is working to lower the risk by flying the BFR/BFS system hundreds of times with cargo before sending humans as well as designing the system for fast transits, to reduce the zero-g deep space radiation exposure. If your position is that robots work now, but humans would be better when it's not so costly/risky, then is Musk's ambition not exactly what we need? __________________ This signature is intended to imitate people.

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