swansont Posted December 19, 2006 Share Posted December 19, 2006 My thoughts exactly. IMHO, NASA was created primarily to put humans into space. The science took a free ride. Exploration for exploration's sake, and doing it with people, is NASA's first and foremost mission. The science, to me, is secondary. From the article: Worse, moon-base nonsense may for decades divert NASA resources from the agency's legitimate missions, draining funding from real needs in order to construct human history's silliest white elephant. This isn't just an opinion. It is an extremely biased opinion. This opinion comes out in every article I've read by Greg Easterbrook. Pray tell, Greg, what are the agency's legitimate missions? There is opinion. But draining money from other missions is fact, and has already happened. The science in unmanned space programs may be better than that in manned space. However, even better science is done on the ground than is done by unmanned space programs and at much less expense. Get rid of people in space, and robotic probes on Mars will have to compete with graduate students out in the field on the surface of the Earth. A robotic probe is incredibly expensive compared to a geology graduate student. A geology graduate student can accomplish more in one weekend than those robots accomplished in two years. Putting people into space is the best justification for going into space, manned or unmanned. You are comparing apples and oranges. There are some things that cannot be done better on the ground (or possibly at all), and have to be done in space. The geology student on the ground may be cheaper, but he or she can't do geology anywhere but earth without space missions; that geology student can't obtain pristine Mars rock samples, not in one, two or even three weekends of work. If cost is the only metric, it's cheaper not to do science at all. But if you want to do science on a budget, and some do, then the manned mission directive is a fiasco. This person expressed my views on robotic exploration quite nicely: From http://www.nasawatch.com/misc/01.09.04.bush.html: The sooner we get President Bush's Exploration Initiative going, the sooner we will get humans to Mars and learn what the planet is all about! I look at the 3+ weeks that it has taken the rovers to drill a little dust off a rock and proclaim it as volcanic. Then I imagine Harrison Schmidt landing, taking his hammer to the rock, and proclaiming the same thing...in about 5 minutes! The Rovers are a prime example of why robots are NOT the way to explore space. And that neatly ignores the many years it will take to get someone there to do that, along with the tremendous cost (both dollars and statistically speaking, lives) that will be involved, and the example of what can be accomplished is something that's already been accomplished. Link to comment Share on other sites More sharing options...
D H Posted December 20, 2006 Share Posted December 20, 2006 There is opinion. But draining money from other missions is fact, and has already happened. It is my opinion that putting people in space is NASA's primary mission. Space science is secondary. That is why I moved from the unmanned space program to manned space 20 years ago. It is unfortunate that Congress is unwilling to fund both science and human exploration to the extent needed to accomplish both ends. There are some things that cannot be done better on the ground (or possibly at all), and have to be done in space. The geology student on the ground may be cheaper, but he or she can't do geology anywhere but earth without space missions; that geology student can't obtain pristine Mars rock samples, not in one, two or even three weekends of work. If cost is the only metric, it's cheaper not to do science at all. But if you want to do science on a budget, and some do, then the manned mission directive is a fiasco. Human spaceflight is more about the spirit of adventure than science. Space science is important, but it is a secondary goal. The spirit of adventure speaks loudly to the public and to decision makers. It is that spirit that fuels NASA's budget. Space science rides on the coattails of human spaceflight. Human spaceflight is expensive. It takes the help of a federal budget to accomplish it. Unmanned space science is "cheap" when compared to human spaceflight, but it is very expensive when compared to Earth-bound science. Yes, there is some science that can only be performed in space. But what is the cost-benefit ratio of that science compared to the cost-benefit ratio of doing other science on the ground? If you want to do science on a budget, and some do, then don't do science in space. Link to comment Share on other sites More sharing options...
calbiterol Posted December 20, 2006 Share Posted December 20, 2006 Human spaceflight is more about the spirit of adventure than science. Space science is important, but it is a secondary goal. The spirit of adventure speaks loudly to the public and to decision makers. It is that spirit that fuels NASA's budget. Space science rides on the coattails of human spaceflight. Precisely. Swansont - what do you mean for the progression of technology being used as a "pro?" That technology for getting to Mars will improve? That has founding. While a moon mission - manned or unmanned - would not make great strides in the field of AI (unless it was created to do so, which is inevitably a waste of money), a moon mission WOULD make great strides in the technology and expertise available for - as well as the feasibility of - a Mars mission. While AI and a mission to the moon aren't necessarily connected, a moon mission and a Mars mission are. And as far as the (7?) second signal delay to the moon goes - I am well aware that automation has reached the point of coping with this, but take it as a metaphor. Imagine a seven-second delay between pressing the brake on your car and the brake being applied. It would make for a rather bad crash. If something went seriously wrong, even with total automation (meaning no human loss), there would still be a MASSIVE economic loss - maybe even the whole "colony." Need I mention that mining works with a number of dangerous chemicals - especially high explosives? Link to comment Share on other sites More sharing options...
swansont Posted December 20, 2006 Share Posted December 20, 2006 Precisely. Swansont - what do you mean for the progression of technology being used as a "pro?" That technology for getting to Mars will improve? That has founding. While a moon mission - manned or unmanned - would not make great strides in the field of AI (unless it was created to do so, which is inevitably a waste of money), a moon mission WOULD make great strides in the technology and expertise available for - as well as the feasibility of - a Mars mission. While AI and a mission to the moon aren't necessarily connected, a moon mission and a Mars mission are. Others have proposed that we mine He-3 on the moon, which hopes that we actually have working fusion reactors by the time we're doing it. There was mention of having better propulsion systems to reduce the time it takes to get to Mars. The technology and expertise to keep people alive that long in space doesn't yet exist. So saying that AI technology isn't currently up to automating systems on the moon as a negative is holding the arguments to different standards. And as far as the (7?) second signal delay to the moon goes - I am well aware that automation has reached the point of coping with this, but take it as a metaphor. Imagine a seven-second delay between pressing the brake on your car and the brake being applied. It would make for a rather bad crash. If something went seriously wrong, even with total automation (meaning no human loss), there would still be a MASSIVE economic loss - maybe even the whole "colony." Need I mention that mining works with a number of dangerous chemicals - especially high explosives? 3.8e8m/3e8m/s x 2 = 2.5s Add in some relays and you get maybe 3 seconds, and that's round-trip, not one-way. It's not an either/or situation. You interact with a computer on your desktop, but it runs many things automatically. The same can be done with equipment. Limited external control with local processing, like sensors to engage the brakes for when the human interaction delay is too long. And humans make mistakes, too, so its not like you have eliminated that problem. Many "dangerous" processes are dangerous only because people are around. Many processes will have to be re-engineered to work in the vacuum and other extreme conditions on the moon. Having humans around just increases the cost (by orders of magnitude). Link to comment Share on other sites More sharing options...
swansont Posted December 20, 2006 Share Posted December 20, 2006 It is my opinion that putting people in space is NASA's primary mission. Space science is secondary. That is why I moved from the unmanned space program to manned space 20 years ago. It is unfortunate that Congress is unwilling to fund both science and human exploration to the extent needed to accomplish both ends. You can have an opinion on what you want NASA's job to be, but not on what they actually do. That's factual. Their mission statement begins with "To advance and communicate scientific knowledge and understanding of the earth, the solar system, and the universe." IOW, science. NASA's "What do we do" says "NASA's mission is to pioneer the future in space exploration, scientific discovery, and aeronautics research. " No mentioned of manned exploration, but does include science. (though they dropped "to understand and protect our home planet" which was viewed by some as a White House move to avoid the topic of global warming) Link to comment Share on other sites More sharing options...
Spyman Posted December 20, 2006 Share Posted December 20, 2006 I think the ultimate goal of humankind is to preserve our species and the best way to achieve race survival is to spread out beyond our solar system, to create independent colonies on planets orbiting other stars. Even if science might be done better/cheaper/safer/faster with automated robotic probes and for sure is necessary, it's still only secondary. We could stay here on Earth and continue to increase our knowledge by unmanned exploration, but if we want to reach the goal we must eventually take a first step. A base on the Moon is for me a small step in the right direction. Link to comment Share on other sites More sharing options...
D H Posted December 20, 2006 Share Posted December 20, 2006 You can have an opinion on what you want NASA's job to be, but not on what they actually do. That's factual. Their mission statement begins with "To advance and communicate scientific knowledge and understanding of the earth, the solar system, and the universe." IOW, science. Nice cherry picking. This is a classic example of the fallacy of quoting out of context. NASA's mission statement, in its completeness, is To advance and communicate scientific knowledge and understanding of the earth, the solar system, and the universe. To advance human exploration, use, and development of space. To research, develop, verify, and transfer advanced aeronautics and space technologies. NASA's "What do we do" says "NASA's mission is to pioneer the future in space exploration, scientific discovery, and aeronautics research. " No mentioned of manned exploration, but does include science. This is more cherry picking. The only appearance of the word "exploration" in NASA's mission statement is preceded by the word "human". Given that, what do you think NASA means when NASA says that what they do is to pioneer the future in space exploration? Continuing on down NASA's "What does NASA do" page, NASA conducts its work in four principle organizations, called mission directorates: Aeronautics: pioneering and proving new flight technologies that improve our ability to explore and which have practical applications on Earth. Exploration Systems: creating new capabilities for affordable, sustainable human and robotic exploration. Science: exploring the Earth, moon, Mars and beyond; charting the best route of discovery; and reaping the benefits of Earth and space exploration for society. Space Operations: providing critical enabling technologies for much of the rest of NASA through the space shuttle, the international space station and flight support. I am not disputing that NASA should do science. NASA should also do human exploration. One can hardly call sending people into low Earth orbit exploration. Both the President and Congress have given NASA the mandate to finally continue the work of human exploration. I, for one, applaud that decision. Link to comment Share on other sites More sharing options...
resuccess Posted December 20, 2006 Share Posted December 20, 2006 Ok is it true that the sey go's up 10 ft on a full moon? http://www.thebusinesssuccessgroup.com/Real-Estate-Investment-training.html Link to comment Share on other sites More sharing options...
calbiterol Posted December 20, 2006 Share Posted December 20, 2006 3.8e8m/3e8m/s x 2 = 2.5s Add in some relays and you get maybe 3 seconds, and that's round-trip, not one-way. First, cut me some slack. I was trying to pull a number out of my memory that I have heard maybe once or twice in my life, and certainly not within the last few years. Second, that isn't the point - my point was, accidents can happen very quickly, and a delay can be prohibitive to preventing them. You interact with a computer on your desktop, but it runs many things automatically. The same can be done with equipment. Limited external control with local processing, like sensors to engage the brakes for when the human interaction delay is too long. And humans make mistakes, too, so its not like you have eliminated that problem. Yes, but computers crash. Systems fail. Files get corrupted. File systems get corrupted. This isn't (always) due to human error. The numerous failed orbiters sent to Mars could have averted destruction/failure had they human pilots or commanders on-site - a conversion error isn't a problem when you're flying by feel. And the difference between humans making errors and computers making errors is that humans have the potential (and often realize it) to know that they have made a mistake. Computers do not. Link to comment Share on other sites More sharing options...
swansont Posted December 20, 2006 Share Posted December 20, 2006 Nice cherry picking. This is a classic example of the fallacy of quoting out of context. NASA's mission statement, in its completeness, isTo advance and communicate scientific knowledge and understanding of the earth, the solar system, and the universe. To advance human exploration, use, and development of space. To research, develop, verify, and transfer advanced aeronautics and space technologies. No. I supplied the context; I said it was the first thing on the list. My interpretation of that is that it is the most important item, it is first. It was presented to counter your contention that their primary mission is to put people into space, and that science is secondary. Omitting the other items on the list does not change that, since they are irrelevant to the point. It would be an example of that fallacy were I contending that NASA shouldn't be putting people into space at all. This is more cherry picking. The only appearance of the word "exploration" in NASA's mission statement is preceded by the word "human". Given that, what do you think NASA means when NASA says that what they do is to pioneer the future in space exploration? Continuing on down NASA's "What does NASA do" page, NASA conducts its work in four principle organizations, called mission directorates: Aeronautics: pioneering and proving new flight technologies that improve our ability to explore and which have practical applications on Earth. Exploration Systems: creating new capabilities for affordable, sustainable human and robotic exploration. Science: exploring the Earth, moon, Mars and beyond; charting the best route of discovery; and reaping the benefits of Earth and space exploration for society. Space Operations: providing critical enabling technologies for much of the rest of NASA through the space shuttle, the international space station and flight support. I am not disputing that NASA should do science. NASA should also do human exploration. One can hardly call sending people into low Earth orbit exploration. Both the President and Congress have given NASA the mandate to finally continue the work of human exploration. I, for one, applaud that decision. The second of my quotes is the first sentence from NASA'a page here: http://www.nasa.gov/about/highlights/what_does_nasa_do.html I took the lead-in paragraph (i.e. an overview/summary) from their own web page. That's not cherry-picking. I am not disputing that NASA should send people into space. What I am disputing is the emphasis they have put on it with this mandate. Practically speaking, it isn't just to continue human exploration, it's to drastically cut back on doing anything else as well. Link to comment Share on other sites More sharing options...
resuccess Posted December 20, 2006 Share Posted December 20, 2006 Ok is it true that the sey go's up 10 ft on a full moon? Link to comment Share on other sites More sharing options...
D H Posted December 20, 2006 Share Posted December 20, 2006 It would be an example of that fallacy were I contending that NASA shouldn't be putting people into space at all. That is exactly the impression you gave when you quoted only the portion of the mission statement that says NASA is to perform space science. You did not give the rest of the mission statement, nor did you provide a link wherein one could find the rest of the mission statement. Cherry-picking. The second of my quotes is the first sentence from NASA's page ... I took the lead-in paragraph (i.e. an overview/summary) from their own web page. That's not cherry-picking. Not cherry picking? BS. Cherry-picking, aka contextotomy, aka red herring, aka what politicians do best, is quoting a portion of some statement and twisting it to mean something other than the original intent. You said, regarding this paragraph, NASA's "What do we do" says "NASA's mission is to pioneer the future in space exploration, scientific discovery, and aeronautics research. " No mentioned of manned exploration, but does include science. You omitted the part of the mission statement that explicitly calls out human exploration. You omitted the part of that same "What does NASA do" web page that qualifies exploration as "human and robotic exploration". Couple those with your statement, and you get cherry-picking as only a politician can do. What office are you running for? I am not disputing that NASA should send people into space. BS. You certainly are disputing that: But if you want to do science on a budget, and some do, then the manned mission directive is a fiasco. What I am disputing is the emphasis they have put on it with this mandate. Practically speaking, it isn't just to continue human exploration, it's to drastically cut back on doing anything else as well. Putting humans into low Earth orbit is not space exploration. NASA has not been meeting its mandate with regard to human space exploration for thirty years. NASA is finally living up to its mandate. They will continue to do space science, at a reduced level. That is the cost of doing human space exploration and doing so without any additional financial backing from the executive and legislative branches of the government. Link to comment Share on other sites More sharing options...
swansont Posted December 21, 2006 Share Posted December 21, 2006 You omitted the part of the mission statement that explicitly calls out human exploration. You omitted the part of that same "What does NASA do" web page that qualifies exploration as "human and robotic exploration". Couple those with your statement, and you get cherry-picking as only a politician can do. What office are you running for? I couldn't have omitted the mission statement, because I wasn't quoting from the page that has the mission statement quoted. On the page from which I quoted, it says "Exploration Systems: creating new capabilities for affordable, sustainable human and robotic exploration" The call for human exploration is not exclusive within the topic of exploration, and exploration is not the only thing NASA does. ALL of this was in rebuttal to your contention that "Exploration for exploration's sake, and doing it with people, is NASA's first and foremost mission." Within that context, all I need to do is present evidence that other objectives have at least equal importance. BS. You certainly are disputing that:(But if you want to do science on a budget, and some do, then the manned mission directive is a fiasco.) I didn't say that NASA shouldn't send people into space. I said the directive was a fiasco; it soaks up a large fraction of the budget and thus prevents science from taking place. i.e. the budget division is a fiasco. I'm done here. You can't seem to let me have a differing opinion, you misrepresent my position (The only position I have advanced is that science shouldn't be ignored) and can't buttress your own position and instead just insult me, so there's really no point in continuing. Link to comment Share on other sites More sharing options...
D H Posted December 22, 2006 Share Posted December 22, 2006 I'm done here. You can't seem to let me have a differing opinion, you misrepresent my position (The only position I have advanced is that science shouldn't be ignored). You claim I didn't say that NASA shouldn't send people into space. and in the same thread say we shouldn't be sending humans to the Moon, to Mars, or even to the Space Station. Where then should we send people? I, for one, am glad that the President and Congress don't share your opinion. NASA isn't ignoring science. It will continue to do science. It will use robots; they are an integral part of the Exploration Initiative. And NASA will once again use humans to do that science. For the last thirty years, NASA has been doing a bad job of fulfilling its mandate for human exploration of space. One can hardly call sending humans into low Earth orbit space exploration. The fiasco is that NASA (and all of science and technology) has been grossly underfunded for the last thirty years. Link to comment Share on other sites More sharing options...
Ndi Posted December 22, 2006 Share Posted December 22, 2006 Yes, but computers crash. Systems fail. Files get corrupted. File systems get corrupted. Desktop computers crash. Dedicated systems are much more resilient and given enough time can become predictable. When was the last time you saw a video camera crash? Or a DVD player? They are computers. Files don't "get corrupted" if you know what the heck you are doing. Do you have any idea how resilient and robust storage can be? Ever tried to think up a way to destroy a multi-mirrored NTFS/ext/whatever? There are configurations that can hot-switch storage as hardware fails without you even knowing. There are configurations that can be made to lose 99 of 100 parallel storage systems and still work as designed. RAID, along with error-tolerant file systems are virtually immune to anything below a nuke. They can even sustain crashing into a planet and still work. Think black box and add one or two orders of magnitude in reliability. Remember, they don't have hard disks. Just because few dollars are pumped into this technology doesn't mean it can or should be dismissed. Link to comment Share on other sites More sharing options...
Ophiolite Posted December 22, 2006 Share Posted December 22, 2006 Astounding! One might have imagined that a twenty plus year veteran of NASA, as DH identifies himself, would be capable of reading. Apparently not. DH, you expressed an opinion (clearly labelling it as such) that NASA's primary goal was human space exploration. As I worked my way through this thread I found SwansonT had elegantly dealt with that: it is fine as an opinion, but it does not reflect the official NASA position. If there is any cherrypicking going on here it is stemming from you. Secondly, SwansonT is objecting to the current plans for manned exploration on the basis that they are ill conceived, fail to adequately focus on the science, and (if I read him right) stem from a political will rather than a scientific goal. He is not objecting to manned spaceflight as such. Now to more serious matters. Could we, on any practical budget, have conducted the exploration of the gas giant systems with manned craft? I am at a loss to see how this would be possible. Equally, the notion of exploring Mars only with robotic craft is insane. A proper Martian exploration program would employ any and every practical means: humans, orbiters, rovers, floaters. I am with Spyman when he says "I think the ultimate goal of humankind is to preserve our species and the best way to achieve race survival is to spread out beyond our solar system, to create independent colonies on planets orbiting other stars." However, Spyman, I disagree with you when you say the moon is a good step. Cut out the middleman. Go for Mars directly. I'm an unabashed Zubrin fan. The delta-V for Mars is little more than that for the Moon. (So yes CPL Luke, it is a matter of scale.) Link to comment Share on other sites More sharing options...
Ndi Posted December 22, 2006 Share Posted December 22, 2006 I thought the Moon was a target for a base not a colony. With the independent resources and low gravity and all. Correct me if I'm wrong. Link to comment Share on other sites More sharing options...
D H Posted December 23, 2006 Share Posted December 23, 2006 The delta-V for Mars is little more than that for the Moon. (So yes CPL Luke, it is a matter of scale.) This is wrong, for several reasons. Facts, not opinions: The crew needs to return to Earth. The return trip from Mars is a lot more expensive than the outgoing trip to Mars while the return trip from the Moon is a lot less than the outgoing trip to the Moon. The total delta-V for a LEO-Mars surface-Earth entry mission is more than double that for a LEO-Lunar surface-Earth entry mission. The vehicle that launches from the surface of Mars needs 5 times the delta-V than the vehicle that launches from the surface of the Moon. For safety reasons, this vehicle will be landed automously, well in advance of the crewed vehicle. That big honking vehicle, full of fuel, has to land on Mars intact, in the right place, and do so without human intervention. The crew needs to stay alive. A lunar mission requires about a week traveling. A minimum energy Mars mission is 12-18 months. Protecting the crew from radiation means a lot more shielding is needed on the Mars vehicle . A lot more shielding equates to a lot more inert mass, and a whole lot more fuel. The crew needs to eat. Packing the food needed for a three to four year Mars mission is not just a matter of scale compared to the food needed for a few months on the Moon. This food is a lot more inert mass that a simple delta-V calculation sweeps under the rug. The crew needs to stay sane. Four people with no one else around for over three years will not stay sane crammed in scaled-up Apollo-style capsule. A larger crew and more space is required for a Mars mission compared to a Lunar mission. The low delta-V to Mars mission assumes aerocapture at Mars. We (the spacefaring nations) have had but partial success with aerocapture. The technology is not at the readiness level needed for human spaceflight. The Mars return vehicle will need to use aerocapture at Earth as well. The Mars return vehicle will plow into the Earth's atmosphere with twice the speed of the Lunar return vehicle. Doubling the speed means quadrupling the energy. Earth aerocapture makes Martian aerocapture look simple. A whole lot of technologies needed for a human mission to Mars are not at the technology readiness level needed for human spaceflight (TRL 9). Several are generously at TRL 3. Link to comment Share on other sites More sharing options...
calbiterol Posted December 23, 2006 Share Posted December 23, 2006 Desktop computers crash. Dedicated systems are much more resilient and given enough time can become predictable. When was the last time you saw a video camera crash? Or a DVD player? They are computers. To be honest, my DVD-player crashed a few weeks ago, and it's not some piece of crap from Wal-Mart. Every component has the possibility of crashing - whether or not it is a software issue. Overheating, miscalculating, manufacturing defects. Even Mars rovers. I quote myself: "The numerous failed orbiters sent to Mars could have averted destruction/failure had they human pilots or commanders on-site - a conversion error isn't a problem when you're flying by feel." The Mars Polar Lander was certainly a failure. The fact that computers crash was an example, not my entire case. Files don't "get corrupted" if you know what the heck you are doing. Do you have any idea how resilient and robust storage can be Frankly, this kind of offended me. I work with computers and file storage every day, and I am very well aware of its limitations and issues. I very much know what I'm doing, and at least one of my files is corrupted per year. I also know that this is due to the fact that I have a number of different working copies spread across multiple media and computers, some of which go through a hefty everyday beating. I certainly know what I'm doing - I've been programming computers since I was 11, much less using them. Also, I know exactly how to force a file to corrupt itself. It's extremely simple and takes about 30 seconds of work, even for multi-mirrored systems. Ever tried to think up a way to destroy a multi-mirrored NTFS/ext/whatever?Yes. Multi-mirrored systems are much more difficult than non-mirrored, but certainly not impossible. Viruses take out systems - even multi-mirrored ones - on a regular basis. As far as non-mirrored goes, I'm currently running Windows on an extremely unstable NTFS file system, and I'm waiting for it to catastrophically fail (again). I have more experience with dead file systems than I would ever want to have. If there is one thing I've learned in my life, it is that EVERYTHING has the potential to fail. Please, guys, don't turn this into a flaming contest. I'd rather not see a useful thread (that I have learned from) become nothing more than a bashfest. Link to comment Share on other sites More sharing options...
D H Posted December 23, 2006 Share Posted December 23, 2006 The "blue screen of death" on ones PC usually occurs because of a software error. The hardware might be extremely reliable, but software is not. Software errors have long plagued the space industry, starting with Mariner 1 and continuing to this day to Ariane 5, Mars Polar Lander, and DART, to name but a few. Link to comment Share on other sites More sharing options...
CPL.Luke Posted December 23, 2006 Share Posted December 23, 2006 computer failure is actually an argument for using robots to explore mars. When humans go to mars we will rely extensively on computers, and beyond that we will have more computers doing more things than a standard robotic probe would have. You can not intuitively guide a craft through re-entry. and even if you succesfully built a method for a pilot to control the craft, how many computers would it take to recognise that when the pilot pushes forward on the joystick which of a dozen thrusters fires in just the right ratio to keep the craft from spinning out of control. Link to comment Share on other sites More sharing options...
D H Posted December 23, 2006 Share Posted December 23, 2006 Manual entry has been done before: Mercury-Atlas 7, Voskhod 2, Apollo 13, for example. Capsule entry is much more forgiving than Shuttle entry. Link to comment Share on other sites More sharing options...
insane_alien Posted December 23, 2006 Share Posted December 23, 2006 DH, aero capture is a bit more tricky as you have to 'bounce' off the atmosphere but just the right amount. the angle window tends to be smaller than for a simple rentry. too slow and you re-enter and to fast and you miss the planet. Link to comment Share on other sites More sharing options...
D H Posted December 23, 2006 Share Posted December 23, 2006 I should have used the word "aeroassist" instead of "aerocapture" in my previous post. Whether a crewed Mars mission uses aerobraking, aerocapture, or direct entry remains to be determined. Direct entry is the easiest of the three. All of these techniques are quite tricky given the high incoming velocity and the imperfect state knowledge at the time of the maneuver. Aeroassist is one of those technologies that is not anywhere near the technology readiness level needed for human spaceflight to Mars. Link to comment Share on other sites More sharing options...
Sayonara Posted January 4, 2007 Share Posted January 4, 2007 The only reason we need for justifying a permanent moon base is that it will prove to us that we can achieve it, and encourage consideration of superior feats. Link to comment Share on other sites More sharing options...
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