I've been trying to understand what the most economical methods for shuttling people to LEO would be using technology currently available or at least available in the near future.
Thanks for the thoughtful responses. I suppose I should have specified a hypothetical unlimited demand, and manufacturing techniques as efficient as reasonably possible, so that neither of those are factors (I understand that they can make a big difference). Yet we really can't have one without the other, can we? For example, if the cost of propellants are as low as they could possibly be and engine efficiency is about as reasonably good as we can expect so that the cost of the propellants alone theoretically required to take an average human to orbit is $20k, that would be a far cry from being affordable for most people. This gives us the theoretical minimum pricing for the service. If we could compare such a service to the airline industry, then fuel would consist of 30-40% of operating costs. Now, if we could send people to LEO for under $100k a pop, this isn't an unreasonable expense for a medium-sized business who might have some commercial interest in working in space (say, some sort of mining company), but most of us won't be taking a space vacation. What I'm wondering is if this is as good as we could possibly get in the foreseeable future? What's the chances of reducing the prices to that of half way around the world airfare? Is our only option revolutionary technology?
Quote from: msat on 05/05/2015 07:15 amThanks for the thoughtful responses. I suppose I should have specified a hypothetical unlimited demand, and manufacturing techniques as efficient as reasonably possible, so that neither of those are factors (I understand that they can make a big difference). Yet we really can't have one without the other, can we? For example, if the cost of propellants are as low as they could possibly be and engine efficiency is about as reasonably good as we can expect so that the cost of the propellants alone theoretically required to take an average human to orbit is $20k, that would be a far cry from being affordable for most people. This gives us the theoretical minimum pricing for the service. If we could compare such a service to the airline industry, then fuel would consist of 30-40% of operating costs. Now, if we could send people to LEO for under $100k a pop, this isn't an unreasonable expense for a medium-sized business who might have some commercial interest in working in space (say, some sort of mining company), but most of us won't be taking a space vacation. What I'm wondering is if this is as good as we could possibly get in the foreseeable future? What's the chances of reducing the prices to that of half way around the world airfare? Is our only option revolutionary technology? It takes a specific amount of energy to get to orbit. As you point out there are limits to how cheap chemical rockets can get. Without science fiction style technologies, getting to orbit will always be far more expensive than air travel.
This is too broad, and just based on your statement above we're really only talking about vehicles that are already in operation (i.e. Soyuz) or are in active development now (i.e. CST-100 and Dragon 2).How many people do you want to carry per trip, and how many trips per year do you require?A good amount of pricing information already exists by the way. For instance, Soyuz flights to the ISS are being sold to NASA for around $70M/seat for two passengers (assuming the Russian pilot is not part of the deliverables), which is the high end of the spectrum, whereas the low end is when Elon Musk said they would be offering rides to LEO for as low as $20M/seat assuming 7 passengers (the Dragon 2 is automated).So $20-70M/seat to LEO is your answer.If the volume climbs the prices should fall, but until reusability of the launch vehicle happens the prices wouldn't fall too much.
...Nor did I mean currently flying machines, which I had hoped I made clear since we already know the prices of those, and they're not in the spirit of this thread.
Passengers per trip is also irrelevant if for instance a 1 passenger rocket can take a person to orbit for $100 instead of one that could take 1,000 people at $1,000,000 per seat.
You were not clear about that.
I'm not the only one that has stated your question is too broad. How can comparisons be made if you don't have anything to compare against? How will you know whether proposed solutions are better than current ones unless you can compare them to current solutions?You obviously are asking this question because you have a specific usage in mind, so just state it.
Single-stage suborbital launch to a rotovator? (This deals with the reentry velocity, too, since it can also be used to slow down the stage before reentry.)Dual-stage rapid reusable assisted by electric jets?Lots of ideas out there. But you probably are looking at a similar number of passengers per flight as typical for airliner traffic here.
I've been trying to understand what the most economical methods for shuttling people to LEO would be using technology currently available or at least available in the near future. Obviously reusability with minimal refurbishment and prep requirements would go the furthest. Next on the list would probably be simplification of the rocket itself in order to lower the initial cost of the machine (assuming it wasn't absurdly high in the first place, which would negate the benefit of reusability), followed by reduced fuel costs. The first two seem well under way by the likes of SpaceX, and apparently Blue Origin. Maybe they both still have room to simplify? Seems unlikely.
Historically all RLV's sacrifice payload for reusability. The question a funder will ask is how much will you lose over an ELV the same size (Musk estimated 30-50% for a semi reusable design). So (the funder will say) "I'm being asked to put up a shed load of cash for something that's 1/2 as "good" (in payload terms) as what customers can already get in the market?Why should I bother?
Unfortunately while the only known LVs that work looks like a re-purposed ICBM it's likely to remain that way with a single builder/single operator model.
Resusability vs expendable are completely independent of the owner vs operator conop.
Quote from: Jim on 05/06/2015 02:08 pmResusability vs expendable are completely independent of the owner vs operator conop.Should be.
It may be broad, but purposely so, as I don't want to unnecessarily limit the discussion. The stated aim is getting passengers to LEO as cheaply as possible, which I thought I clearly stated.
How should that be measured?
Cost for a single human? A group of 4 humans? A group of 100 humans? They may all have different solutions.How will you know when the best solution has been found?
Does a larger passenger capacity necessarily make it more economical?It would seem there's a few benefits to using smaller reusable launchers (we'll stick with talking about the first stage for now). The smaller size simplifies aspects like ground handling.......In many ways, both in the short and long term, three 2-passenger scooters is more economical than one big 6-passenger SUV, even when 6 people are being transported at all times.
I think in the history of engineering, there has never been a "best" solution, only the most practical given the body of knowledge and capabilities of that time. Given that, we should still be able to distinguish between a good solution and a bad one. Throwing away complex rockets is an example of an obviously bad solution to the question at hand.
It would seem to me that separating manufacturers from operators would be antithetical to maximum cost reduction, assuming all other factors being equal.
The major benefit separation provides for the manufacturer is being to weather a storm in poor performing market segments (it's the operator that gets hit the worst). But then again, a 5-10% price-per-seat difference is unlikely to result in a make-or-break situation, unless there's some fierce competition.
Why? There is no reason that the manufacturer of reusable launch vehicles can't be the operator. There isn't enough business to support multiple operators and despite cost reductions, there still might not be that much of an increase in business to warrant it.
Also, there is no reason that a manufacturer of ELV can't sell them to operators.
It has nothing to do with expendable or reusable. I don't buy this thinking that there is an ICBM mentality in ELV contractors.
Does a larger passenger capacity necessarily make it more economical?
It would seem there's a few benefits to using smaller reusable launchers (we'll stick with talking about the first stage for now).
The smaller size also allows for a more efficient structure such as the balloon-type of the original Atlas, which (correct me if I'm wrong) wouldn't scale well to a larger rocket, thus cheaper and more robust (read: heavier) engines could be used.
In many ways, both in the short and long term, three 2-passenger scooters is more economical than one big 6-passenger SUV, even when 6 people are being transported at all times.
That's in essence the question. What are the different (but practical) solutions? The metric is cost per seat. I believe demand would be plenty if pricing is sufficiently low and there's space/lunar stations to accommodate the passengers. I understand that in those cases, the cost of transportation to LEO is only a chunk of the overall cost, but it would still represent a significant chunk.
You might like to check you understand the difference between cost (what it costs me to make something) and price (what I'm going to charge you to buy it).
Then you're not talking about an RLV at all. You're talking about a semi reusable system. In which case the costs will converge (fairly quickly) on the cost of the upper stage and cost of refurbishment.
Perhaps you should look at the size of the original Atlas. it was quite big. The tanks were Convairs solution to the fairly poor engines available then. The tradeoff in 1st stage is something like a weight gain of 6-13 units causes a drop in payload of 1 unit. For the upper stage it's roughly 1 to 1.
You've got a chicken and egg situation. What's the incentive for the operator to put somewhere in LEO for humans to go in the first place.
Virgin Galactic demonstrated there is a market for space tourism. So as a price point if $250k gets you 15 mins of sub orbital let's say $1m for a day in space?
BTW Musk said the F9 propellant bill is about $120k. so if you can run your operation at 3x that ($260K) you can offer a price people can pay and still make a major profit.
You appear to have some kind of architecture you've been thinking about and want to discuss. Why don't you tell us what you think is the right way to do things?
While every payload needs a coupled loads analysis to ensure it won't be shaken to bits (or shake the LV to bits) the link between "operator" and "manufacturer" will remain so close as for them to be virtually indistinguishable, outside of accountancy.
I don't buy this thinking that there is an ICBM mentality in ELV contractors.
It would seem to me that separating manufacturers from operators would be antithetical to maximum cost reduction, assuming all other factors being equal. The major benefit separation provides for the manufacturer is being to weather a storm in poor performing market segments (it's the operator that gets hit the worst). But then again, a 5-10% price-per-seat difference is unlikely to result in a make-or-break situation, unless there's some fierce competition.
Quote from: Jim on 05/06/2015 04:07 pmI don't buy this thinking that there is an ICBM mentality in ELV contractors.I agree. The last U.S. ICBM development effort was, when, during the 1980s with MX? Most of the contractors involved don't even exist today, at least not in their 1980's Cold War era form. - Ed Kyle
Starting off with my usual mantra; Spacecraft are not aircraft and vice versa!During the commercial aircraft ramp up several aircraft companies started out operating or involved in operating airlines but this quickly became counter productive as they could make MORE money by selling aircraft to other operators rather than being restricted to only the "airlines" they were involved with. This actually ended up biting Boeing in the keester when they introduced the Model 247 (http://en.wikipedia.org/wiki/Boeing_247) which was so popular they couldn't actually produce enough aircraft to satisfy demand which opened the door to Douglas with their DC-1.
But we're still along way from being anywhere near that model with space launch, unless of course "something" changes the equations
One thing that I think gets overlooked a bit in this thread is the exact premise: "People" to "LEO"
Flight rate in this case is pretty much paramount. Never mind the "actual" market we're assuming there is one for the moment and the question is basically what makes that cheaper and I think it would be very hard to argue large numbers of passengers and few flights would work in those circumstances so you want MORE flights even if the number of passengers is fewer.Hence turn-around time and reusability are both high priorities with minimum up-front cost and overall operations costs as low as you can get them. Which is pretty much the opposite of the current situation.
I think modular, mass produced self-contained thrusters that can be clustered together in multiple stages should be the way to go. Also, having many of them on a vehicle reduces the risk of mission failure.Surely not the most efficient way in use of materials, but if production and quality control can be automated it would decrease the cost tremendously.Before you think I'm some genius, I wasn't the first with this idea http://www.astronautix.com/lvs/otrag.htm
The real lowest cost way to shuttle people to orbit will be found when there is a) Multiple ways to do it. b) Multiple vendors of those systems, ideally supply multiple operators of those systemsc) No restriction on which vendor you use.
There first has to be a good reason for people to go into space before that happens
There are plenty of good reasons for people to go into space, just not ones you agree with.
Quote from: john smith 19 on 05/09/2015 11:44 amThe real lowest cost way to shuttle people to orbit will be found when there is a) Multiple ways to do it. b) Multiple vendors of those systems, ideally supply multiple operators of those systemsc) No restriction on which vendor you use. There first has to be a good reason for people to go into space before that happens
Quote from: Jim on 05/09/2015 12:17 pmThere first has to be a good reason for people to go into space before that happensThere are plenty of good reasons for people to go into space, just not ones you agree with.
Quote from: Borklund on 05/09/2015 11:55 pmThere are plenty of good reasons for people to go into space, just not ones you agree with.Quite wrong. There are few to none good reasons that are economical viable, which is needed to make it sustainable.
Needs are just wants felt more immediately - probably Mises.
Folks, the thread ASSUMES there IS a "good reason" for getting people into LEO in numbers, it is in fact the usual "chicken/egg" issue in fact at the moment but we're assuming the need is there.
Back to the OP again, there is really a need to define some parameters on the "market" to be able to define the "best" method. For example, if your yearly "market" is 100 people to orbit (very early projections for a LEO tourism market with a much lower but still pretty high price) then having a vehicle capable of putting more than about 9 people per month is a waste. Further if your market consists of 100 people a month (very difficult to justify at this point) but they are divided between several destinations (say 4, 25 passengers each) then having a vehicle capable of putting 100 people per flight into orbit is not a good solution.
The Rutan Quickie was marketed as a 1-place $4,000 (1979, so ~$13k now) aircraft, capable of around 100MPG with an 18hp engine (could probably do better with a more efficient modern engine, especially diesel). According to the following blog post (https://blogs.law.harvard.edu/philg/2007/03/19/airbus-a380-more-fuel-efficient-than-a-toyota-prius/), a loaded, all economy seating A380 with 850 passengers gets similar fuel economy. It would require 850 Quickies to carry the same amount of passengers as a single A380, but it would do so at a price of roughly $11M, compared to the ~$430M for the A380. Granted, the A380 is a far more capable aircraft all around (except its runway requirements, heh). Now, it wouldn't be practical to replace all airliners with quickies, if for no other reason than the sheer amount would congest the runways (but in terms of space access, we're so far away from having that problem). But lets just say we could, mass manufacturing would bring the unit as well as parts cost down further, so we'd get even more passenger transport capabilities for the money. Maintenance could be standardized and tasks such as structures inspection could probably be largely automated (imagine an automatic car-wash, but with X-rays and sophisticated data processing software, etc.), which are things you can't do when you only have a few thousand (MASSIVE) units spread around the globe. Ok, that's enough of the apples to carrots to pork chops comparison.
This is a key point. What is the "shape" of the market?
As for the market size, I guess it's not fair to say "unlimited", while at the same time using current-day figures is boring for the sake of discussion. One of the big points I was trying to make is how to reduce costs to the point where the pricing enables a larger customer base (even if the customers are wealthy by most standards) over current options. Lets just say the market is big enough to justify the development costs of RLVs. Realistically speaking, SpaceX is in the best position as they have one LV which they could use for passengers, cagro, and satellite payloads, thus spreading the NRE for the core rocket tech as much as possible. But that doesn't make a fun discussion, does it?
Thanks Randy for thought-provoking response and keeping to the topic of the OP.
I must admit that it is a bit silly to consider practical, near-term solutions to a hypothetical situation which is unlikely to come to fruition any time soon. And at any rate, any "practical" solutions depend on so many factors, with at least a handful of them brought up in this thread already. I think that makes the topic that much more interesting.
What I'm still not entirely convinced of is that a larger LV capable of carrying more passengers is more efficient overall than smaller ones, even if there's enough passengers to justify its size. Though I admit the issue brought up earlier in this thread with docking so many spacecraft to a space station is one of the best arguments against it.I'm going to further argue in favor of smaller & cheaper LVs, and while I know it's a stretch to apply the following to this topic, I still want to entertain this thought:
The more I think about it, the more I like the jet-powered LAP concept. As you point out, it should be much simpler (and thus cheaper) to develop than a specially designed aircraft. Even if we could use an existing aircraft, the performance would be much lower than what is possible for a LAP. For one, the speed and altitude could be greatly increased over the flight regime jet engines are typically suited for via LOX/water injection (perhaps around Space Shuttle staging velocity and altitude?). The simpler structure should also make aerodynamic heating more easily managed than a full-on airplane of comparable performance.
(some snippage)You could have more cross range or build it so that it can land at an airport (ideally in a state that allows it's self ferry back to base). You'll probably want either more cross range or > 24 hr endurance so the launch site comes back under its orbital track without requiring enormously high cross range. BTW one interesting calculation you can do on a spreadsheet is to run the rocket equation with different levels of Isp and partial delta V's and losses to orbit. High Isp (relative to a rocket) means you have a structure which is much heavier than any known rocket, but only air breathers give 1000's of seconds of Isp. Once your breathing air winged lift lets you lift mass 3x take off thrust, although the Launch Assist Platform with afterburning and inlet fluid (either LOX or water) injection can give you a (relatively) simple 1st stage structure with high thrust at ground level and maximum payload (exactly where you need it) while sustaining acceleration up to maybe M4 without exotic technology like SCRamjets. The improvement on the available mass fraction for structure is quite remarkable.
Your just missing a couple of small details in your comparison.
On the one hand you're saying "What's the smallest you can make it?" and on the other you're saying "What's the most economical you can build?"
High Isp (relative to a rocket) means you have a structure which is much heavier than any known rocket
How do you figure? I don't see why that would inherently be the case.
Seriously a number would help msat
SpaceX and CST100 are both 7 "people" as payload, call one of them a "pilot" and round down that's 6. Currently they can't launch but every couple of months and there's only one "destination" which is the ISS.So we could "assume" a scenario based on 8 people per month, 96 a year but that 'technically' wouldn't even strain the system we have assuming we get a third provider. I also don't think it would help lower costs all that much. Anyone have suggestions for a "conservative" number?
Your on the NSF-forums, "speculation" is a way of life around here However your correct we DO have to define the problem and parameters if we're going to keep going which is what I'd like to see happen.
Your "Quickie" analogy breaks down hard, even before the issues of range and speed: How many passengers on an A380 can fly a "Quickie" let alone the A380 they are on? So as JS19 points out you have to have an automated flight systems which would NOT be cheap nor easy to install in a "Quickie" and you'd have to (in the example) build, test, install, and test 850 of them.
Lets talk a bit more relevant one:7 Falcon-1s versus 1 Falcon-9 with Crew-Dragon.Using the numbers from the following site (for reference ONLY people ):http://www.spacelaunchreport.com/falcon.htmlF-1e would put 1mT (1000kg/2205lb) so lets "assume" for a moment that we could make a single person, automated spacecraft reentry vehicle AND fit a person and some "supplies" inside it and launch it on the F-1e. The cost to do so quoted on the above site is $9.1 million dollars. SpaceX quotes a Falcon-9 launch at $61.2 million, so at its most basic the Falcon-1 option costs at least $63.7 million while the single Falcon-9 only costs $61.2 million. F9 is $2.5 million less than multiple F1es. (And this is before the added costs of developing and building the automated one-person capsules for the F1e)Now you can still argue that multiple "smaller" launches more often does in fact make more economic sense in some cases and it does. But in general I don't see it being economical for personnel launch without some sort of "infrastructure system" in place (such as the suggested launch loop or skyhook/rotovator, etc) where you are transferring people constantly. Even then I doubt single person vehicles will be cost effective.(Of course someone WILL argue differently and one such person is Danni Eder who originally came up with the jet-LAP assisted launch concept at Boeing who has a google book he's working on here: http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methodshttp://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Human_TransportWhere he argues the case for single person transports)
If you haven't yet I'd recommend taking a read of these threads:http://forum.nasaspaceflight.com/index.php?topic=29160.0http://forum.nasaspaceflight.com/index.php?topic=26680.0;allhttp://forum.nasaspaceflight.com/index.php?topic=25095.0;allAnd I'll jump on the most "obvious" flaw before anyone else does: If your rocket stages are your main turn around driver then having a stage that you CAN actually turn around faster doesn't help you. ... Unless you have multiple rocket stage sets waiting for launch that is
Quote from: RanulfC on 05/12/2015 02:54 pmSeriously a number would help msat I really don't know. How sustainable are these suborbital services, and what kind of frequency will they be flying with? Maybe those can give us some figures to work with.
Well, there doesn't have to be a destination for space "tourism", but Dragon V2 wouldn't offer much of a view given its tiny hatch window. That doesn't preclude SpaceX, or a partner from rolling out their own space stations (BA comes to mind). But this still remains a chicken<->egg scenario which won't change unless someone is willing to take a lot of risks and invest (luckily some are). Maybe some major high-end hotel chains would like the prestige of having a space hotel, particularly the very first one?
I didn't specify the piloting as I felt it was somewhat besides the point. The vast majority of LV/spacecraft have been fully or highly automated. I think you looked too far into the details of quickie flight controls, but I'd argue that it's not as far fetched of an idea as you seem to indicate.
QuoteLets talk a bit more relevant one:7 Falcon-1s versus 1 Falcon-9 with Crew-Dragon.Using the numbers from the following site (for reference ONLY people ):http://www.spacelaunchreport.com/falcon.htmlF-1e would put 1mT (1000kg/2205lb) so lets "assume" for a moment that we could make a single person, automated spacecraft reentry vehicle AND fit a person and some "supplies" inside it and launch it on the F-1e. The cost to do so quoted on the above site is $9.1 million dollars. SpaceX quotes a Falcon-9 launch at $61.2 million, so at its most basic the Falcon-1 option costs at least $63.7 million while the single Falcon-9 only costs $61.2 million. F9 is $2.5 million less than multiple F1es. (And this is before the added costs of developing and building the automated one-person capsules for the F1e)Now you can still argue that multiple "smaller" launches more often does in fact make more economic sense in some cases and it does. But in general I don't see it being economical for personnel launch without some sort of "infrastructure system" in place (such as the suggested launch loop or skyhook/rotovator, etc) where you are transferring people constantly. Even then I doubt single person vehicles will be cost effective.(Of course someone WILL argue differently and one such person is Danni Eder who originally came up with the jet-LAP assisted launch concept at Boeing who has a google book he's working on here: http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methodshttp://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Human_TransportWhere he argues the case for single person transports)But how would the F1 price fair if its design allowed for more automated manufacturing? Particularly when the lesser amount of big rockets wouldn't allow for it.
Going by passenger capacity, were're at a ratio of 7:1 (or 6:1 if we really need a pilot). With the costs per passenger between the F1 and F9 being so close to one another, it's really hard to know which was the scales would tip as it's dependent on so many factor.
Thanks for the links. Looks like good stuff!
QuoteIf you haven't yet I'd recommend taking a read of these threads:http://forum.nasaspaceflight.com/index.php?topic=29160.0http://forum.nasaspaceflight.com/index.php?topic=26680.0;allhttp://forum.nasaspaceflight.com/index.php?topic=25095.0;allAnd I'll jump on the most "obvious" flaw before anyone else does: If your rocket stages are your main turn around driver then having a stage that you CAN actually turn around faster doesn't help you. ... Unless you have multiple rocket stage sets waiting for launch that is I'll check out these links soon. Thanks.If you have numerous RLVs, then I think it's fair to say you could pipeline your operation so you're not waiting on any single unit to be refurbed/prepped before your next scheduled launch. That maximizes your launch availability.
I don't think those will help either, specifically its about as much of a "possible" rather than actual market as orbital travel is The main question is what kind of traffic is needed to support multiple providers? "Technically" the ISS resupply and crew exchange is that with 3 people and several cargo flights per year, but its not really a commercial market at the moment. We could assume some multiple of "6" passengers per month, with each "provider" carrying a load ever other month which would be a fantastic number compared to current rates. But if you look at it that's only four flights per year per carrier not counting any "cargo" or other payload flights. Suggestions?
Actually the studies say that having a "destination" and not going up for simply a couple of orbits and return is the more "desired" tourism route. Going around the Earth a couple of times is seen as little better than a shorter (and cheaper) suborbital trip and all things being equal (reusability, turn around time and other factors wise) you get more throughput with less technical and engineering issues with the latter than the former.
(Seriously, IMHO most suborbital companies are going about it the wrong way because they are actually all trying for "orbital" capability eventually. Suborbital Class-1 {straight up and back down} would be better served by a combination jet/rocket powered single-stage VTVL vehicle using MIPCC-modified surplus F100s and a simple robust set of H2O2/kerosene rockets similar to the RL40 {http://www.hydrogen-peroxide.us/history-US-Reaction-Motors/AIAA-2001-3838_History_of_RMI_Super_Performance_90_Percent_H2O2-Kerosene_LR-40_RE-pitch.pdf} which was as easy to maintain as a standard jet engine of the time. Up and down 20 passengers per hour 10 hours a day...)
Hilton, (not Bigelow who keeps telling everyone he has NO ambition to develop space hotels but would rather "rent-space" to government or commercial operations, which is a very different thing) has said that once he felt that the technology and access issues were resolved to his satisfaction he's be willing to put up a space hotel. Similarly there was a Japanese company that made similar statements before the second financial collapse. What most people don't realize is the amount of support infrastructure and personnel that are required to "service" the high end tourism market which is NOT represented by any current "space-tourist" who are by and large much more willing to put up with fewer (or none mostly) amenities. A good figure of merit is about 4 "service" people per tourist in an enclosed environment system, and that's a very minimum number with the "average" being about three times that when you consider dedicated maintenance and "behind-the-scenes" service personnel.
One thing I never see anyone really considering is that each "paying passenger" to a space station is never just paying for THEIR seat but for everyone that will be going in support with them and all the cargo and support for their stay
The Quickie is actually a good example with mostly simply flight controls however it takes some skill to fly properly and there isn't much room (by design) for automation As most pilot will tell you "flying" is easy (as long as nothing goes wrong and the weather is good) taking off can be tricky and landing is a bear. In the capsule example all that would be computer and ground controlled so it would in fact be "easier" than flying a plane, but most smart designers NEVER design for things to go "right" all the time
Both F1 and F9 are pretty automated at this point. F1's manufacturing was a 'scale-run' of what they do for the F9 so the price difference would be negligible.
Launching multiple F1s requires multiple pads, multiple launch crews as well and support equipment so the price is going to be higher as a basic factor. The reason that multiple smaller load to orbit "works" with systems like gun-launch, launch-loop, etc is the basic cost of the "launch" is lower per launch than that of a "standard" rocket launch at least in theory. Theory tends to break down in places like the orbital services end of things due to varied delivery and attitude changes introduced by a "static" launch system though.
Your still going to have "choke-points" but your correct that a properly designed system will minimize those if possible In the cited case you only need a few jet-LAPS but enough rocket stages to keep up the launch rate while others are being turned. Pretty much the whole idea for a LAP is to allow enough margin for robust reusability in the LV stages.Randy
The larger vehicle is going to be more mass efficient as a lot of things such as docking hardware and avionics are won't increase much in mass over the small vehicle.MMOD protection and insulation will benefit from the square cube law.
a space elevator is coming, people. Just be patient.
Space elevator cannot get anybody into LEO.
Plus the van Allen belts will fry you.
Quote from: QuantumG on 05/18/2015 06:30 amPlus the van Allen belts will fry you.This thread's about the most economical way, not the safest way.
The ISS figures are pretty much useless. One flight a month even on a fully RLV won't do much for making access as cheap as possible, would it?
Really, what I had in mind when I started this thread was getting people to LEO to board space stations and interplanetary shuttles and the like. In which case, earth->LEO transit would only be a fraction of the overall cost. And in the event such infrastructure existed in any large-ish scale, I guess there's probably better methods of getting to LEO than using rockets.
Well, sure. But that doesn't mean there wouldn't be a market for destination-less orbital flights. Particularly true if the price of access could come anywhere close to the range upcoming suborbital services are targeting.
I somewhat agree in terms of current suborbital designs being all wrong, but my craft would look a bit different than yours I'd probably go with a jet-powered HTOL therefore capable of zoom climbs and then use decomposed N2O (and maybe water) for jet oxidizer supply above a certain altitude. I find H2O2 pretty scary. You might be thinking self-pressurized N2O is scary too (which it is) but you can have a small pump and a decomposition chamber and thus pressurize the N2O with the resulting oxygen and nitrogen, instead of the much less stable gaseous N2O.
I vaguely recall hearing Hilton make that comment. As far as the kinds of service and amenities the rich would expect, my guess is that with those requirements, most rich people couldn't afford it. If potential tourists can't get over the fact that space accommodations imply minimalist living, then their won't be much space tourism at all.
I wonder how staff costs relate to all other costs. I'd also assume that in-space staff would stay there for a longer duration than the tourists. Shuttling all the staff with each customer would not be very economical.
Apparently you never seen this: http://www.popsci.com/xavion-ipad-app-can-make-emergency-airplane-landing-autopilotThe amount of compute power and sensor integration in a typical smart phone is more than enough to control an airplane from taxi to touchdown.
Does it require multiple pads? That would really only be true if a larger vehicle has enough launches to keep them largely utilized. But if a larger LV makes use of a pad once a month, vs several times a month for a smaller LV, then I don't see how it would be necessary. As for crew and support equipment, well, you're likely going o be paying a crew regardless. I don't see many skilled workers/technicians willing to take an hourly paid job that only requires maybe a few days of work per month.