A kerosene-fueled X-33 as a single stage to orbit vehicle.
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From: J. Clarke on 14 Apr 2010 07:23 On 4/14/2010 2:22 AM, Matt wrote: > On Tue, 13 Apr 2010 10:57:59 -0400, J. Clarke wrote: > >> On 4/13/2010 1:43 AM, Matt wrote: >>> On Sun, 11 Apr 2010 18:34:10 -0400, J. Clarke wrote: >>> >>>> On 4/11/2010 3:21 PM, Matt wrote: >>>>> On Sun, 11 Apr 2010 14:57:00 -0400, J. Clarke wrote: >>>>> >>>>>> On 4/11/2010 1:59 PM, Matt wrote: >>>>>>> On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: >>>>>>> >>>>>>>> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: >>>>>>>>> Note also that use of the rocket thrust from the X-33 would also allow >>>>>>>>> you to reach higher speeds say Mach 3+ before release. This would >>>>>>>>> allow greater payload, since less delta-V would need to be supplied by >>>>>>>>> the X-33 after release. The extra rocket propellant for the X-33 >>>>>>>>> required for firing during the linked portion of the trip would be >>>>>>>>> carried in the carrier craft fuselage. >>>>>>>>> >>>>>>>>> Bob Clark >>>>>>>> >>>>>>>> Since you need to reach Mach 25+ to orbit this saves you only 12% of >>>>>>>> the speed requirement while imposing a requirement for an airframe >>>>>>>> that can at least sustain that ground velocity while climbing. >>>>>>>> >>>>>>>> A much better result can be had from a balloon-assisted launch system >>>>>>>> where the objective is to start the rocket with as much altitude as >>>>>>>> possible rather than speed. >>>>>>>> >>>>>>>> http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system >>>>>>> >>>>>>> This is a proposal from 2008. Was it approved? >>>>>> >>>>>> That's not a "proposal", it's a student exercise. Google "Glenn Academy". >>>>> >>>>> http://academy.grc.nasa.gov/y2007/research-projects/group-project-proposal >>>>> Goals in Project Choice >>>>> + Useful to NASA >>>>> >>>>> It would appear that NASA approved the choice of the project topic. >>>> >>>> Just as any teacher approves the choice of the topic of term papers and >>>> other student projects. >>> >>> I don't know about you, but it wasn't a requirement for my senior >>> project that it be "useful to the university." >>> >>> >>>>> Did the "proposal" not receive some level of review within NASA? >>>> >>>> The same review that any educational project gets. >>>> >>>>> Else it was simply a time-wasting exercise. >>>> >>>> By that logic all education is "a time wasting exercise". The purpose >>>> of education is not to come up with wonderful new ways of doing things, >>>> it's to teach students what we already know. >>> >>> All of education isn't geared toward evaluating technology for >>> potential application. >> >> So what? We aren't talking about "all education", we are talking about >> one specific exercise. > > Actually, we were talking about a concept. Someone put a "proposal" > label on it. You seem convinced that it was merely an exercise. I > think the program is poorly conceived if that's all it was. So how in your expert opinion do you believe NASA _should_ go about conducting a summer workshop for college students? >>> Does research assistance done by university >>> students *never* help "to come up with wonderful new ways of doing >>> things?" >> >> Whether it helps or not, its purpose is to teach the student. > > Can a task not have more than one purpose? Most tasks do. What of it? >>> Did you do intern work in college? If so, did the company you worked >>> for not want results they could use? >> >> When one does "intern work" one is working for an employer, one is not >> engaging in a training exercise. > > In my experience, it was both. Most work is educational in one way or another, but that is not its purpose. >> You don't seem to grasp the concept of "exercise". > > I understand what an exercise is. I also know what it is to enter > fully-charged from college into a not-as-advertised intern > environment. It can be demoralizing to a college student. What, work came as a shock to you? In any case, we are talking about a summer workshop conducted by a government agency, not about an internship. >>>>> Perhaps consistent with the >>>>> environment, but that's another issue. >>>> >>>> The environment is a summer training program for college students. >>> >>> It's an elite program. Students who achieve entry deserve better than >>> to be taught how to spin their wheels on a project that no one cares >>> about. >> >> So what should they do, be put right to work as engineers on something >> that will kill people when it crashes? > > Isn't that what an apprentice aircraft mechanic does? After he has been through his basic training program, and under supervision, he is allowed to perform a limited set of tasks--when he has mastered those, then he gets to do more. But mechanics are not engineers. > Why *when* it crashes? Give the students some credit. They actually do > know a thing or two. Do you assume that they are incapable of > designing something that works? Not incapable, no, sometimes they get lucky. But that's not the way to bet. Lots of book-smart and no practical sense. >>> If no one cared about it, then "proposal" was just so much NASA-speak. >>> If some one did care about it, then it received some level of >>> consideration beyond what was given to my senior project. >> >> It was an exercise in proposal-writing. Geez. > > Is that NASA's product? Proposals? What does "NASA's product" have to do with the subject of a training exercise? > Or maybe it was more. > http://academy.grc.nasa.gov/archives/535 > The high altitude launch of their group project (a balloon assisted > launch system) is scheduled for August 30, 2008 with StratoStar LLC in > Indiana. > > If it was only an exercise in writing proposals, why did they plan to > launch anything? As backup for the proposal. That was stated in the proposal. You've never actually sold anything to the government, have you? > http://academy.grc.nasa.gov/main/mission-statement > Its primary objectives are to: > 1. Provide upper level undergraduate/first-second year graduate > students cutting-edge research opportunities with NASA scientists, > engineers, and educators. > > "The vision of the Academy as described by its founder, Dr. Gerald > Soffen is 'To give possible leaders a view into how NASA, the > university community, and the private sector function, set their > priorities, and contribute to the success of the aerospace program.'" > > I merely asked what happened to a "proposal" cited as a reference for > a "better" way to launch objects. It got a "Duh!" response from you. > Perhaps that was amiss. You asked, I ventured an opinion. You chose to become argumentative and to show how smart you were by telling us all about the purposes of this proposal which, by your own admission, you know nothing about. Can you say "netloon"?
From: Matt on 15 Apr 2010 03:10 On Wed, 14 Apr 2010 07:23:51 -0400, J. Clarke wrote: >On 4/14/2010 2:22 AM, Matt wrote: >> On Tue, 13 Apr 2010 10:57:59 -0400, J. Clarke wrote: >> >>> On 4/13/2010 1:43 AM, Matt wrote: >>>> On Sun, 11 Apr 2010 18:34:10 -0400, J. Clarke wrote: >>>> >>>>> On 4/11/2010 3:21 PM, Matt wrote: >>>>>> On Sun, 11 Apr 2010 14:57:00 -0400, J. Clarke wrote: >>>>>> >>>>>>> On 4/11/2010 1:59 PM, Matt wrote: >>>>>>>> On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: >>>>>>>> >>>>>>>>> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: >>>>>>>>>> Note also that use of the rocket thrust from the X-33 would also allow >>>>>>>>>> you to reach higher speeds say Mach 3+ before release. This would >>>>>>>>>> allow greater payload, since less delta-V would need to be supplied by >>>>>>>>>> the X-33 after release. The extra rocket propellant for the X-33 >>>>>>>>>> required for firing during the linked portion of the trip would be >>>>>>>>>> carried in the carrier craft fuselage. >>>>>>>>>> >>>>>>>>>> Bob Clark >>>>>>>>> >>>>>>>>> Since you need to reach Mach 25+ to orbit this saves you only 12% of >>>>>>>>> the speed requirement while imposing a requirement for an airframe >>>>>>>>> that can at least sustain that ground velocity while climbing. >>>>>>>>> >>>>>>>>> A much better result can be had from a balloon-assisted launch system >>>>>>>>> where the objective is to start the rocket with as much altitude as >>>>>>>>> possible rather than speed. >>>>>>>>> >>>>>>>>> http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system >>>>>>>> >>>>>>>> This is a proposal from 2008. Was it approved? >>>>>>> >>>>>>> That's not a "proposal", it's a student exercise. Google "Glenn Academy". >>>>>> >>>>>> http://academy.grc.nasa.gov/y2007/research-projects/group-project-proposal >>>>>> Goals in Project Choice >>>>>> + Useful to NASA >>>>>> >>>>>> It would appear that NASA approved the choice of the project topic. >>>>> >>>>> Just as any teacher approves the choice of the topic of term papers and >>>>> other student projects. >>>> >>>> I don't know about you, but it wasn't a requirement for my senior >>>> project that it be "useful to the university." >>>> >>>> >>>>>> Did the "proposal" not receive some level of review within NASA? >>>>> >>>>> The same review that any educational project gets. >>>>> >>>>>> Else it was simply a time-wasting exercise. >>>>> >>>>> By that logic all education is "a time wasting exercise". The purpose >>>>> of education is not to come up with wonderful new ways of doing things, >>>>> it's to teach students what we already know. >>>> >>>> All of education isn't geared toward evaluating technology for >>>> potential application. >>> >>> So what? We aren't talking about "all education", we are talking about >>> one specific exercise. >> >> Actually, we were talking about a concept. Someone put a "proposal" >> label on it. You seem convinced that it was merely an exercise. I >> think the program is poorly conceived if that's all it was. > >So how in your expert opinion do you believe NASA _should_ go about >conducting a summer workshop for college students? Perhaps they are already closer to my ideal than yours in the quote from their mission statement says "contribute to the success of the aerospace program.' >>>> Does research assistance done by university >>>> students *never* help "to come up with wonderful new ways of doing >>>> things?" >>> >>> Whether it helps or not, its purpose is to teach the student. >> >> Can a task not have more than one purpose? > >Most tasks do. What of it? You seem fixated on the notion that there is one and only one reason for a student to be involve in an activity: to learn. Learning by doing also makes a contribution beyond going through the motions of an academic exercise. >>>> Did you do intern work in college? If so, did the company you worked >>>> for not want results they could use? >>> >>> When one does "intern work" one is working for an employer, one is not >>> engaging in a training exercise. >> >> In my experience, it was both. > >Most work is educational in one way or another, but that is not its purpose. Says who? You speak for all who run work-study programs, do you? >>> You don't seem to grasp the concept of "exercise". >> >> I understand what an exercise is. I also know what it is to enter >> fully-charged from college into a not-as-advertised intern >> environment. It can be demoralizing to a college student. > >What, work came as a shock to you? And you call me argumentative? > In any case, we are talking about a >summer workshop conducted by a government agency, not about an internship. And you see no similarity? If not, I think you're missing something. >>>>>> Perhaps consistent with the >>>>>> environment, but that's another issue. >>>>> >>>>> The environment is a summer training program for college students. >>>> >>>> It's an elite program. Students who achieve entry deserve better than >>>> to be taught how to spin their wheels on a project that no one cares >>>> about. >>> >>> So what should they do, be put right to work as engineers on something >>> that will kill people when it crashes? >> >> Isn't that what an apprentice aircraft mechanic does? > >After he has been through his basic training program, and under >supervision, he is allowed to perform a limited set of tasks--when he >has mastered those, then he gets to do more. Yet he works - with supervision - on something that could kill people *if* it crashes. >But mechanics are not engineers. So? You've never seen a mechanic have a better idea than the engineers working on a project? This attitude also fits with my final question in this post. >> Why *when* it crashes? Give the students some credit. They actually do >> know a thing or two. Do you assume that they are incapable of >> designing something that works? > >Not incapable, no, sometimes they get lucky. But that's not the way to >bet. Lots of book-smart and no practical sense. Which is why it is wise for them to work with supervision. >>>> If no one cared about it, then "proposal" was just so much NASA-speak. >>>> If some one did care about it, then it received some level of >>>> consideration beyond what was given to my senior project. >>> >>> It was an exercise in proposal-writing. Geez. >> >> Is that NASA's product? Proposals? > >What does "NASA's product" have to do with the subject of a training >exercise? I read that one of the criteria for the project was for it to be "important to NASA." If NASA's aim is to amass piles of proposals, then training students to write dust-collecting proposals would be fitting. If not, then maybe they are giving a piece of some real action to people who can handle it. >> Or maybe it was more. >> http://academy.grc.nasa.gov/archives/535 >> The high altitude launch of their group project (a balloon assisted >> launch system) is scheduled for August 30, 2008 with StratoStar LLC in >> Indiana. >> >> If it was only an exercise in writing proposals, why did they plan to >> launch anything? > >As backup for the proposal. That was stated in the proposal. > >You've never actually sold anything to the government, have you? So was it just an exercise or were they actually trying to "sell" an idea? >> http://academy.grc.nasa.gov/main/mission-statement >> Its primary objectives are to: >> 1. Provide upper level undergraduate/first-second year graduate >> students cutting-edge research opportunities with NASA scientists, >> engineers, and educators. >> >> "The vision of the Academy as described by its founder, Dr. Gerald >> Soffen is 'To give possible leaders a view into how NASA, the >> university community, and the private sector function, set their >> priorities, and contribute to the success of the aerospace program.'" >> >> I merely asked what happened to a "proposal" cited as a reference for >> a "better" way to launch objects. It got a "Duh!" response from you. >> Perhaps that was amiss. > >You asked, I ventured an opinion. You chose to become argumentative and >to show how smart you were by telling us all about the purposes of this >proposal which, by your own admission, you know nothing about. > >Can you say "netloon"? You were dismissive of the students' efforts. Can you say "snob?"
From: J. Clarke on 15 Apr 2010 07:50 On 4/15/2010 3:10 AM, Matt wrote: > On Wed, 14 Apr 2010 07:23:51 -0400, J. Clarke wrote: > >> On 4/14/2010 2:22 AM, Matt wrote: >>> On Tue, 13 Apr 2010 10:57:59 -0400, J. Clarke wrote: >>> >>>> On 4/13/2010 1:43 AM, Matt wrote: >>>>> On Sun, 11 Apr 2010 18:34:10 -0400, J. Clarke wrote: >>>>> >>>>>> On 4/11/2010 3:21 PM, Matt wrote: >>>>>>> On Sun, 11 Apr 2010 14:57:00 -0400, J. Clarke wrote: >>>>>>> >>>>>>>> On 4/11/2010 1:59 PM, Matt wrote: >>>>>>>>> On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: >>>>>>>>> >>>>>>>>>> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: >>>>>>>>>>> Note also that use of the rocket thrust from the X-33 would also allow >>>>>>>>>>> you to reach higher speeds say Mach 3+ before release. This would >>>>>>>>>>> allow greater payload, since less delta-V would need to be supplied by >>>>>>>>>>> the X-33 after release. The extra rocket propellant for the X-33 >>>>>>>>>>> required for firing during the linked portion of the trip would be >>>>>>>>>>> carried in the carrier craft fuselage. >>>>>>>>>>> >>>>>>>>>>> Bob Clark >>>>>>>>>> >>>>>>>>>> Since you need to reach Mach 25+ to orbit this saves you only 12% of >>>>>>>>>> the speed requirement while imposing a requirement for an airframe >>>>>>>>>> that can at least sustain that ground velocity while climbing. >>>>>>>>>> >>>>>>>>>> A much better result can be had from a balloon-assisted launch system >>>>>>>>>> where the objective is to start the rocket with as much altitude as >>>>>>>>>> possible rather than speed. >>>>>>>>>> >>>>>>>>>> http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system >>>>>>>>> >>>>>>>>> This is a proposal from 2008. Was it approved? >>>>>>>> >>>>>>>> That's not a "proposal", it's a student exercise. Google "Glenn Academy". >>>>>>> >>>>>>> http://academy.grc.nasa.gov/y2007/research-projects/group-project-proposal >>>>>>> Goals in Project Choice >>>>>>> + Useful to NASA >>>>>>> >>>>>>> It would appear that NASA approved the choice of the project topic. >>>>>> >>>>>> Just as any teacher approves the choice of the topic of term papers and >>>>>> other student projects. >>>>> >>>>> I don't know about you, but it wasn't a requirement for my senior >>>>> project that it be "useful to the university." >>>>> >>>>> >>>>>>> Did the "proposal" not receive some level of review within NASA? >>>>>> >>>>>> The same review that any educational project gets. >>>>>> >>>>>>> Else it was simply a time-wasting exercise. >>>>>> >>>>>> By that logic all education is "a time wasting exercise". The purpose >>>>>> of education is not to come up with wonderful new ways of doing things, >>>>>> it's to teach students what we already know. >>>>> >>>>> All of education isn't geared toward evaluating technology for >>>>> potential application. >>>> >>>> So what? We aren't talking about "all education", we are talking about >>>> one specific exercise. >>> >>> Actually, we were talking about a concept. Someone put a "proposal" >>> label on it. You seem convinced that it was merely an exercise. I >>> think the program is poorly conceived if that's all it was. >> >> So how in your expert opinion do you believe NASA _should_ go about >> conducting a summer workshop for college students? > > Perhaps they are already closer to my ideal than yours in the quote > from their mission statement says "contribute to the success of the > aerospace program.' > > >>>>> Does research assistance done by university >>>>> students *never* help "to come up with wonderful new ways of doing >>>>> things?" >>>> >>>> Whether it helps or not, its purpose is to teach the student. >>> >>> Can a task not have more than one purpose? >> >> Most tasks do. What of it? > > You seem fixated on the notion that there is one and only one reason > for a student to be involve in an activity: to learn. Learning by > doing also makes a contribution beyond going through the motions of an > academic exercise. > >>>>> Did you do intern work in college? If so, did the company you worked >>>>> for not want results they could use? >>>> >>>> When one does "intern work" one is working for an employer, one is not >>>> engaging in a training exercise. >>> >>> In my experience, it was both. >> >> Most work is educational in one way or another, but that is not its purpose. > > Says who? > > You speak for all who run work-study programs, do you? > > >>>> You don't seem to grasp the concept of "exercise". >>> >>> I understand what an exercise is. I also know what it is to enter >>> fully-charged from college into a not-as-advertised intern >>> environment. It can be demoralizing to a college student. >> >> What, work came as a shock to you? > > And you call me argumentative? > > >> In any case, we are talking about a >> summer workshop conducted by a government agency, not about an internship. > > And you see no similarity? If not, I think you're missing something. > > >>>>>>> Perhaps consistent with the >>>>>>> environment, but that's another issue. >>>>>> >>>>>> The environment is a summer training program for college students. >>>>> >>>>> It's an elite program. Students who achieve entry deserve better than >>>>> to be taught how to spin their wheels on a project that no one cares >>>>> about. >>>> >>>> So what should they do, be put right to work as engineers on something >>>> that will kill people when it crashes? >>> >>> Isn't that what an apprentice aircraft mechanic does? >> >> After he has been through his basic training program, and under >> supervision, he is allowed to perform a limited set of tasks--when he >> has mastered those, then he gets to do more. > > Yet he works - with supervision - on something that could kill people > *if* it crashes. > >> But mechanics are not engineers. > > So? You've never seen a mechanic have a better idea than the engineers > working on a project? This attitude also fits with my final question > in this post. > > >>> Why *when* it crashes? Give the students some credit. They actually do >>> know a thing or two. Do you assume that they are incapable of >>> designing something that works? >> >> Not incapable, no, sometimes they get lucky. But that's not the way to >> bet. Lots of book-smart and no practical sense. > > Which is why it is wise for them to work with supervision. > > >>>>> If no one cared about it, then "proposal" was just so much NASA-speak. >>>>> If some one did care about it, then it received some level of >>>>> consideration beyond what was given to my senior project. >>>> >>>> It was an exercise in proposal-writing. Geez. >>> >>> Is that NASA's product? Proposals? >> >> What does "NASA's product" have to do with the subject of a training >> exercise? > > I read that one of the criteria for the project was for it to be > "important to NASA." If NASA's aim is to amass piles of proposals, > then training students to write dust-collecting proposals would be > fitting. If not, then maybe they are giving a piece of some real > action to people who can handle it. > > >>> Or maybe it was more. >>> http://academy.grc.nasa.gov/archives/535 >>> The high altitude launch of their group project (a balloon assisted >>> launch system) is scheduled for August 30, 2008 with StratoStar LLC in >>> Indiana. >>> >>> If it was only an exercise in writing proposals, why did they plan to >>> launch anything? >> >> As backup for the proposal. That was stated in the proposal. >> >> You've never actually sold anything to the government, have you? > > So was it just an exercise or were they actually trying to "sell" an > idea? > > >>> http://academy.grc.nasa.gov/main/mission-statement >>> Its primary objectives are to: >>> 1. Provide upper level undergraduate/first-second year graduate >>> students cutting-edge research opportunities with NASA scientists, >>> engineers, and educators. >>> >>> "The vision of the Academy as described by its founder, Dr. Gerald >>> Soffen is 'To give possible leaders a view into how NASA, the >>> university community, and the private sector function, set their >>> priorities, and contribute to the success of the aerospace program.'" >>> >>> I merely asked what happened to a "proposal" cited as a reference for >>> a "better" way to launch objects. It got a "Duh!" response from you. >>> Perhaps that was amiss. >> >> You asked, I ventured an opinion. You chose to become argumentative and >> to show how smart you were by telling us all about the purposes of this >> proposal which, by your own admission, you know nothing about. >> >> Can you say "netloon"? > > You were dismissive of the students' efforts. > > Can you say "snob?" Oh to Hell with it. Can you say <plonk>? >
From: Robert Clark on 17 Apr 2010 01:13 In another thread I argued that the idea frequently written about in early science fiction of millionaires producing their own manned orbital craft may soon be approaching: Newsgroups: rec.arts.sf.science, rec.arts.sf.written From: Robert Clark <rgregorycl...(a)yahoo.com> Date: Mon, 30 Nov 2009 22:18:09 -0800 (PST) Subject: Old time stories about the millionaire rocket developer? http://groups.google.com/group/rec.arts.sf.science/msg/43026ea12c347d1b?hl=en However, the calculation of the Falcon 1 first stage with more efficient engines having SSTO capability leads me to a surprising conclusion: it won't even have to be millionaires who could have such craft. For instance to "own", in the sense of live in, a million dollar home you don't have to have a million dollar income or even a million dollar net worth. You just have to make the mortgage payments, which per year can be a fraction of the million dollar cost of the home. This is in the salary range of many just upper class individuals. Then such orbital rockets with financing will be in the cost range of many such individuals. A combination of factors suggest this is possible. First, with mass production the cost of the rocket structure and of the engines will drop significantly. Also, though the Falcon 1 is priced at about $8 million, remember a large proportion of this is to cover development cost. The large majority of this cost was for the development of the engines. But neither of these two SpaceX engines would be used for the SSTO purpose. Instead would be used the much cheaper for their size Russian engines. We can estimate how much they would cost based on their size and the costs for much larger, i.e., more powerful, Russian engines. The 1,000,000 lbs. thrust RD-180 costs $10 million. The 400,000 lbs. thrust NK-33 costs $4 million. Based on this we can estimate the cost of the 60,000 lbs. thrust RD-0124 I was recommending for the SSTO purpose as $600,000. Another reason for why such SSTO's will be lower cost than the $8 million Falcon 1 is that the manufacturing cost is actually only a fraction of the launch cost. See for example the estimates in Tables 3 and 4 here: When Physics, Economics, and Reality Collide. The Challenge of Cheap Orbital Access. by John M. Jurist, M.D., Sam Dinkin, Ph.D, David Livingston, DBA http://www.colonyfund.com/Reading/papers/phys_econ_leo.html#elv Note then the methods for achieving such high mass ratios as with the Falcon 1 first stage don't appear to be especially hard. See for example the description of the Falcon 1 propellant tanks given here: Falcon 1 Overview. http://www.spacex.com/falcon1.php#first_stage They appear to use a combination of methods known for decades such as a common bulkhead and an isogrid design. So using these methods, similar high mass ratios could easily be achieved by other aerospace companies. Actually little in research and development costs would be required for the structures. There is another key cost that figures into launch costs mentioned in the "When Physics, Economics, and Reality Collide. The Challenge of Cheap Orbital Access" article. That is the cost of range access, usually provided by governments. With wide numbers of privately owned rockets launching daily this cost could be reduced significantly. A big component of the research and development costs however would be the actual flight tests. This would be significantly reduced with reusable systems. For this to have a high demand you would need for it to be manned- flight capable. The Falcon 1e sized SSTO would require two RD-0124 engines for a 1,800 kg payload capacity, but would be able to loft a Project Mercury-sized capsule: Mercury. http://www.braeunig.us/space/specs/mercury.htm You would also need a lightweight reentry system. Inflatable heat shields may fit the bill: NASA Launches New Technology: An Inflatable Heat Shield. 08.17.09 http://www.nasa.gov/topics/aeronautics/features/irve.html Pod People. They're the ones thinking outside the space capsule. * By James Oberg * Air & Space Magazine, November 01, 2003 "IN 1964, MOST VIEWERS OF TELEVISED SPACE "SHOTS," AS THEY WERE CALLED THEN, knew what it took to protect a spacecraft from the fire of reentry. It took big, heavy shields bolted to pressurized metal vessels. One of the most nerve-racking moments of the early space program had been the final minutes of John Glenns 1962 Mercury flight, when Mission Control waited to learn whether his shield had remained attached to the Friendship 7 capsule during the violent return. "Two years later, on June 10, 1964, another, much lighter vehicle entered the atmosphere with no one on board. In engineering terms it was nearly as daring as the Mercury flights had been. Launched on a sounding rocket to an altitude of 96 miles over New Mexico, the craft dove back toward Earth at a speed of more than 5,000 mph. Being so light, it didnt generate as much heat from atmospheric friction as Glenns capsule had, so it had only a thin coating of thermal protectionno shield. Odder still, it was inflated like a balloon in a Thanksgiving day parade." http://www.airspacemag.com/space-exploration/cit-oberg.html This second, which involves a lifting body inflatable heat shield, would result in significant reduction in reentry heating by making use of shapes optimized for high lift/drag ratio at hypersonic speed. Bob Clark On Mar 14, 9:24 pm, Robert Clark <rgregorycl...(a)yahoo.com> wrote: > The SpaceLaunchReport.com site operated by Ed Kyle provides the > specifications of some launch vehicles. Here's the page for the Falcon > 1: > > Space Launch Report: SpaceX Falcon Data Sheet.http://www.spacelaunchreport.com/falcon.html > > Quite interesting is that the total mass and dry mass values for the > Falcon 1 first stage with Merlin 1C engine give a mass ratio of about > 20 to 1. This is notable because a 20 to 1 mass ratio is the value > usually given for a kerosene-fueled vehicle to be SSTO. However, this > is for the engine having high vacuum Isp ca. 350 s. The Merlin 1C with > a vacuum Isp of 304 s probably wouldn't work. > However, there are some high performance Russian kerosene engines that > could work. Some possibilities: > > Engine Model: RD-120M.http://www.astronautix.com/engines/rd120.htm#RD-120M > > RD-0124.http://www.astronautix.com/engines/rd0124.htm > > Engine Model: RD-0234-HC.http://www.astronautix.com/engines/rd0234.htm > > However, I don't know if this third one was actually built, being a > modification of another engine that burned aerozine. > > Some other possibilities can be found on the Astronautix site: > > Lox/Kerosene.http://www.astronautix.com/props/loxosene.htm > > And on this list of Russian rocket engines: > > Russian/Ukrainian space-rocket and missile liquid-propellant engines.http://www.b14643.de/Spacerockets_1/Diverse/Russian%20engines/engines... > > The problem is the engine has to have good Isp as well as a good T/W > ratio for this SSTO application. There are some engines listed that > even have a vacuum Isp above 360 s. However, these generally are the > small engines used for example as reaction control thrusters in orbit > and usually have poor T/W ratios. > For the required delta-V I'll use the fact that a dense propellant > vehicle may only require a delta-V of 8,900 m/s, compared to a > hydrogen-fueled vehicle which may require in the range of 9,100 to > 9,200 m/s. The reason for this is explained here: > > Hydrogen delta-V.http://yarchive.net/space/rocket/fuels/hydrogen_deltav.html > > Then when you add on the fact that launching near the equator gives > you 462 m/s for free from the Earth's rotation, we can take the > required delta-V that has to be supplied by the kerosene-fueled > vehicle as 8,500 m/s. > I'll focus on the RD-0124 because of its high Isp, 359 s vacuum and > 331 s sea level. On the "Russian/Ukrainian space-rocket and missile > liquid-propellant engines" page its sea level thrust is given as > 253,200 N, 25,840 kgf. However, the Falcon 1 first stage weighs 28,553 > kg. So we'll need two of them. Each weighs 480 kg, so two would be 960 > kg. This is 300 kg more than the single Merlin 1C. So the dry mass of > the Falcon 1 first stage is raised to 1,751 kg. There is a RD-0124M > listed on the Astronautix page that only weighs 360 kg, but its sea > level Isp and thrust are not given, so we'll use the RD-0124 until > further info on the RD-0124M is available. > Taking the midpoint value of the Isp as 345 s we get a delta-V of > 345*9.8ln(1 + 27102/1751) = 9,474 m/s (!) Note also the achieved delta- > V would actually be higher than this because the trajectory averaged > Isp is closer to the vacuum value since the rocket spends most of the > time at altitude. > This calculation did not include the nose cone fairing weight of 136 > kg. However, the dry mass for the first stage probably includes the > interstage weight, which is not listed, since this remains behind with > the first stage when the second stage fires. Note then that the > interstage would be removed for the SSTO application. From looking at > the images of the Falcon 1, the size of the cylindrical interstage in > comparison to the conical nose cone fairing suggests the interstage > should weigh more. So I'll keep the dry mass as 1,751 kg. > Now considering that we only need 8,500 m/s delta-V we can add 636 kg > of payload. But this is even higher than the payload capacity of the > two stage Falcon 1! > We saw that the thrust value of the RD-0124 is not much smaller than > the gross weight of the Falcon 1 first stage. So we can get a vehicle > capable of being lifted by a single RD-0124 by reducing the propellant > somewhat, say by 25%. This reduces the dry weight now since one > RD-0124 weighs less than a Merlin 1C and the tank mass would also be > reduced 25%. Using an analogous calculation as before, the payload > capacity of this SSTO would be in the range of 500 kg. > We can perform a similar analysis on the Falcon 1e first stage that > uses the upgraded Merlin 1C+ engine. Assuming the T/W ratio of the > Merlin 1C+ is the same as that of the Merlin 1C, the mass of the two > of the RD-124's would now be only 100 kg more than the Merlin 1C+. > The dry mass and total mass numbers on the SpaceLaunchReport page for > the Falcon 1e are estimated. But accepting these values we would be > able to get a payload in the range of 1,800 kg. This is again higher > than the payload capacity of the original two stage Falcon 1e. In fact > it could place into orbit the 1-man Mercury capsule. > The launch cost of the Falcon 1, Falcon 1e is only about $8 million - > $9 million. So we could have the first stage for that amount or > perhaps less since we don't need the engines which make up the bulk of > the cost. How much could we buy the Russian engines for? This article > says the much higher thrust RD-180 cost $10 million: > > From Russia, With 1 Million Pounds of Thrust. > Why the workhorse RD-180 may be the future of US rocketry. > Issue 9.12 | Dec 2001 > "This engine cost $10 million and produces almost 1 million pounds of > thrust. You can't do that with an American-made engine."http://www.wired.com/wired/archive/9.12/rd-180.html > > This report gives the price of the also much higher thrust AJ26-60, > derived from the Russian NK-43, as $4 milliion: > > A Study of Air Launch Methods for RLVs. > Marti Sarigul-Klijn, Ph.D. and Nesrin Sarigul-Klijn, Ph.D. > AIAA 2001-4619 > "The main engine is currently proposed as the 3,260 > lb. RP-LOX Aerojet AJ26-60, which is the former > Russian NK-43 engine. Thrust to weight of 122 to > 1 compares to the Space Shuttle Main Engines > (SSME) 67 to 1 and specific impulse (Isp = 348.3 > seconds vacuum) is 50 to 60 seconds better than > the Atlas II, Delta II, or Delta III RP-LOX engines. > A total of 831 engines have been tested for > 194,000 seconds. These engines are available for > $4 million each, which is about 10% the cost of a > SSME."http://mae.ucdavis.edu/faculty/sarigul/aiaa2001-4619.pdf > > Then the much lower thrust RD-0124 could quite likely be purchased > for less than $4 million. So the single RD-0124 powered SSTO could be > purchased for less than $12 million. > > Even though the mathematics says it should be possible, and has been > for decades, it is still commonly believed that SSTO performance with > chemical propulsion is not possible even among experts in the space > industry: > > Space Tourism is a Hoax > By Fredrick Engstrom and Heinz Pfeffer > 11/16/09 09:02 AM ET > "In 1903, the Russian scientist Konstantin Tsiolkovsky established the > so-called rocket equation, which calculates the initial mass of a > rocket needed to put a certain payload into orbit, given that the > orbital speed is fixed at 28,000 kilometers per hour, and that the > maximum speed of the gas exhausted from the rocket that propels it > forward is also fixed. > "You quickly find that the structure and the tanks needed to contain > the fuel are so heavy that you will never be able to orbit a > significant payload with a single-stage rocket. Thus, it is necessary > to use several rocket stages that are dumped on the way up to get any > net mass, i.e. payload, into orbit. > "Let us look at the most successful rocket on the market the > European Ariane 5. Its start weight is 750 tons, of which 650 tons are > fuel, 80 tons are structure and around 20 tons are left for low Earth > orbit payload. > "You can have a different number of stages, and you can look for minor > improvements, but you can never get around the fact that you need big > machines that are staged to reach orbital speed. Not much has happened > in propulsion in a fundamental sense since Wernher von Brauns Saturn > rocket. And there is nothing on the horizon, if you discount > controlling gravity or some exotic technology like that. In any case, > it is not for tomorrow."http://www.spacenews.com/commentaries/091116-space-tourism-hoax.html > > The Cold Equations Of Spaceflight. > by Jeffrey F. Bell > Honolulu HI (SPX) Sep 09, 2005 > "Why isn't Mike Griffin pulling out the blueprints for X-30/NASP, DC-X/ > Delta Clipper, or X-33/VentureStar? Billions of dollars were spent on > these programs before they were cancelled. Why aren't we using all > that research to design a cheap, reusable, Single-Stage-To-Orbit > vehicle that operates just like an airplane and doesn't fall in the > ocean after one flight?" > "The answer to this question is: All of these vehicles were fantasy > projects. They violated basic laws of physics and engineering. They > were impossible with current technology, or any technology we can > afford to develop on the timescale and budgets available to NASA. They > were doomed attempts to avoid the Cold Equations of Spaceflight."http://www.spacedaily.com/news/oped-05zy.html > > Then it is important that such a SSTO vehicle be produced even if > first expendable to remove the psychological barrier that it can not > be done. Once it is seen that it can be done, and in fact how easily > and cheaply it can be done, then there it will be seen that in fact > the production of SSTO vehicles are really no more difficult than > those of multistage vehicles. > Then will be opened the floodgates to reusable SSTO vehicles, and low > cost passenger space access as commonplace as trans-oceanic air > travel. > > Bob Clark
From: Robert Clark on 17 Apr 2010 02:00
On Mar 18, 3:02 pm, Robert Clark <rgregorycl...(a)yahoo.com> wrote: > In the first post of this thread I calculated that switching to > kerosene would allow the hydrogen-fueled suborbital X-33 to now become > an orbital craft. However, I thought it would be able to carry minimal > payload if any. > However, I realize I used too low a value for the density of chilled > LOX at 1,160 kg/m^3. It should be actually about 10% higher than the > usual 1,142 kg/m^3. > > This is described here: > > Alternate Propellants for SSTO Launchers. > Dr. Bruce Dunn > Adapted from a Presentation at: > Space Access 96 > Phoenix Arizona > April 25 - 27, 1996http://www.dunnspace.com/alternate_ssto_propellants.htm > > In table 2 it gives the densities of some chilled fuels including > kerosene, i.e., RP-1, and of LOX. The density given for the chilled > kerosene is 867 kg/m^3, and for LOX 1,262 kg/m^3. So for the 296 m^3 > volume I was taking for the X-33 propellant tanks and a 2.7 mixture > ratio for the NK-33 engine, this gives a kero/LOX propellant mass of > 332,600 kg. > Now taking the average Isp of the NK-33 as 315 s, this gives a delta-V > for the 21,700 kg dry mass, reconfigured X-33 of 8,797 m/s. But when > you take into account you get a 462 m/s velocity boost for free from > launching at the equator, you only need about 8,500 m/s delta-V to be > provided by the rocket to reach orbit. > This allows us to add payload. Adding 2,300 kg payload, the delta-V > becomes 8,500 m/s, sufficient for orbit. We can actually get higher > payload than this by using more energetic hydrocarbons than kerosene. > For instance in table 2 of Dunn's paper on alternate SSTO propellants, > he gives the payload for chilledmethylacetylene/LOX as 24% higher > than for chilled kero/LOX. This would be a payload of 2,850 kg. > These payload amounts would also allow the X-33 to carry a 2 man crew > in its 5 by 10 foot payload bay in a tandem arrangement a la the F-14 > seating arrangement. > So you could get a fully reusable, SSTO vehicle at much reduced price > than the full-sized VentureStar. This article gives the price to build > a new X-33 as $360 million in 1998 dollars: > > Adventure star.http://www.flightglobal.com/pdfarchive/view/1998/1998%20-%203141.html > > Even taking into account inflation, the cost to build the kerosene- > fueled version should be comparable or perhaps even less because of > the drop in prices for carbon composites and because kerosene engines > are generally cheaper than hydrogen ones. > The launch preparation costs should also be low since the X-33 was > expected to be operated by only a 50 man ground crew compared to the > 18,000 required for the shuttle system: > > Lockheed Secret Projects: Inside the Skunk Works. > By Dennis R. Jenkinshttp://books.google.com/books?id=DUkl5bH6k6EC&lpg=PA95&dq=x-33%20vent... > > Say the builder expected 25% profit over costs of the vehicle over 100 > flights. That would be a charge of $4.5 million per flight. At a 2,850 > kg payload capacity that would be $1,580 per kilo, or $720 per pound, > to orbit. Not as good as the full-sized VentureStar but still > significantly better than current launch prices. > > Note that the other half-scale suborbital demonstrators for the NASA > RLV program by Rockwell and McDonnell-Douglas (see images linked > below) could be built for comparable prices and would likewise become > full orbital craft by switching to kerosene or other dense propellant. > Then we could have 3 separate designs for fully reusable SSTO vehicles > at costs that could allow fully private financing that would > significantly reduce launch costs and would allow manned flights. > > Successful operation of these X-33-sized orbital vehicles at a profit > would encourage private financing to build the full-scale VentureStar- > sized RLV's that could bring launch costs down to the $100 to $200 per > kilo range. > > BobClark > > http://www.astronautix.com/nails/x/x33rock.jpg > > http://www.astronautix.com/graphics/x/x33p4.jpg So the dense propellant fueled X-33 could serve as a reusable SSTO for small payloads or manned launch at a reduction in launch cost by a factor of 5 to 10 times. The Obama administration is deciding to continue the development of the Orion capsule, though not the solid motor boosters of the Ares I and V. This is interesting because a kerosene-fueled X-33 could also serve as a first stage booster for the Orion and its upper stage. Then many of the jobs dependent on the Ares system other than those related to the ATK solid rocket motors could be retained, and ATK already has other contracts for expendable boosters anyway. This would also result in a 50% reduction in the costs to space by using a reusable/ expendable hybrid system according to Air Force estimates. This page gives the specifications of the Ares I: Space Launch Report - Ares I. http://www.spacelaunchreport.com/ares1.html The gross weight including payload is given as 912,660 kg and the gross weight of the first stage as 732,550 kg. So the gross weight of the Ares I second stage plus payload is 180,110 kg. In post #2 of this thread I calculated the reconfigured X-33 with three NK-33 engines would carry 307,000 kg of kerosene/LOX and have a dry weight of 21,700 kg. So the gross weight with the 180,110 kg of the second stage plus payload would be 307,000 + 21,700 + 180,110 = 508,810 kg. However, the 3 NK-33's would only put out 463,000 kgf. at sea level. So we'll add a fourth NK-33. This will bring the dry weight of the X-33 to 22,922 kg, the total gross weight to 510,032 kg, and the sea level thrust to 617,000 kgf. Using the average Isp of the NK-33 as the midpoint of the sea level and vacuum Isp's at 315 s, the achieved delta-V would be 315*9.8*ln(508,810/(22,922+180,110)) = 2,836 m/s, a bit more than the equivalent delta-V, speed + altitude, provided by the Ares I first stage. The achieved delta-V is actually higher than this since the rocket spends most of the time at high altitude, where the Isp is closer to the vacuum value. Bob Clark |