The "Real Aerospace" Thread

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Mikk
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Re: The "Real Spacecraft" Thread

Post by Mikk »

Well, as anticarrot mentioned SpaceX, he might be thinking of the Falcon Heavy project as a near-match for dreams of SLS spec lift capacity. For the moment it appears the success of the already delayed deployment of FH is pending on the successful demonstration of the upgrades developed for the Falcon 9, which should be launching with the preformance and manufacturing process improved engine upgrade sometime this summer.

Not to sound too much like a crash-craving spectator, but the whole cluster of modifications that are expected to be rolled out with the uprated F9 version 1.1 have quite a bit of exitement potential. If nothing else than a dramatic outcome of the first test of post-jettison first stage aerobatics whether it's a flop OR a success. That, and if things go as planned americans will have cheaper space launch than Proton-M! Us poor Europeans are left playing with launch costs per unit mass twice as high :o

Considering how safety concious (despite driving perhaps the most competitive launch price for a new rocket family yet (that I've been able to find anyway)) that particular rocket manufacturer is, betting on catastrophic failure on their next flight doesn't seem like the good choice.


Despite the suggestion that FH would be trying to share much of it's hardware with the F9 colleague we might, for the sake of argument, view Falcon Heavy and the Space Launch System projects as ideas on paper.

Code: Select all

FH       vs SLS:
53       vs 70...130 kg (thousands) Mass to LEO
83...128 vs 500  $ (millions)
Soon     vs Maybe Later
Viable   vs To Be Finanially Proven
Safety-oriented VS solid rocket boosters
:P
As for the usefulness of resurrecting Saturn technology? Well, those things weren't engineered to be cheap either.

Whether we believe them or not, SpaceX is claiming to be on the crusade to develop cheap, safe, marinized and reusable (Merlin 1C or 1D (I forget which) have been claimed to be useful for up to 20 launch test burns) launch vehicles, and re-entry cargo return vehicles. NASA certainly seems to be buying their sales pitch.

Orion crew capsule is probably going to beat the DragonRider to the first manned flights tho. Wel'll have to wait and see how well the ideas for Dragon-derived robotic missions other than cargo-ferry will work out aswell.

Slightly related topic:

How soon after a company filing a patent is it readable by the general public? Just wondering how much more easy it might be for hardcore rocketry fans to keep track of space-launch companies' tech developments if company X were to file patents.
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anticarrot
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Re: The "Real Spacecraft" Thread

Post by anticarrot »

Arioch wrote:What is it specifically that you think is silly about SLS?
A launch vehicle should be designed to put stuff into orbit as cheaply and reliably as possibly. The SLS was required to use components from the shuttle; a launch system characterised by it's expense and unreliability. There is a reason it is nicknamed the Senate Launch System.
If you want to put large payloads in orbit, then you need some kind of reliable, low-cost heavy lift rocket.
This is an error. Large and heavy are not the same thing. Size pre deployment and post deployment can also very by an order of magnitude. But beyond that... What payload are you thinking of that cannot be broken down into 50 or 30 ton pieces? And that's a question even NASA can't answer.

When they do it's circular logic. "The moon lander we specificallydesigned for the SLS won't fit on a smaller vehicle so we need the SLS." Here's a challenge. Sit down and do the maths and work out how much useful payload your choice of upper stage can softland on the moon from lunar orbit. It'll be far in excess of NASA's severely self-censored dreams. We don't need custom hardware for every single application. One patch of vacuum is completely identical to another patch as far as a rocket engine is concerned.
Neither a spaceplane nor a DC-Y could fulfill this role.
The DC-Y wouldn't need to launch a lunar lander. The DC-Y could BE a lunar lander (with 30 tons of cargo) via direct-return, aerobreaking and an orbital fuel depot. That would take about 40 launches (mostly for fuel) which wouldn't be a particular problem for DC-I if it functioned as advertised. As for space planes, Reaction Engines has plans for a MArs transport. So they apparently disagree with you. :P
It's hard to build space stations or interplanetary exploration vehicles 9 tonnes at a time.
Explain please, with examples. Because we build EVERYTHING ELSE HUMANKIND HAS EVER USED out of pieces smaller than 9 tonnes. Sorry, but this claim really don't hold water, and it's immensely frustrating to see it repeated over and over again.

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Re: The "Real Spacecraft" Thread

Post by Nemo »

Well, technically, the component bolts and nuts and pannels only weigh in at ounces to pounds each, why use nine tons! Thats too big! There is a cost associated with building in situ versus doing it prefab under controlled conditions. Every time you have to launch a new piece, every time you have to put those pieces together in space wearing a suit, theres a great deal more that can go wrong. More variables, more possibility for failures, more things that cant be tested properly before hand. It introduces more risk into the program, and these programs are inherently risk averse.

Larger / more massive constructions will have capability and redundancy smaller units do not. You chose the lander in your earlier example, the Apollo 17 mission brought a grand total of 110.5 kg of samples back with them. The Altair program was looking to increase sample capacity to as much as 800 kg, or more if possible. Again, risk aversion comes into play. 2 of the 17 Apollo missions failed, one resulted in the total loss of the crew. Assume for a minute the same failure rate held true today. You want 800kg returned at either 100 kg per mission or 800 kg per mission. Youre looking at what, a 36% chance the 8 missions required will go right, and a 50/50 shot of the total loss of crew? Thats not really a fair comparison, we engineer things a bit differently these days. Lets take the failure rate and cut it to a third of what it was. 72% chance of success. Ok, still too low. The shuttle had a much better service record with 2 failures in 135 shots, both total crew loss events. Using that metric theres an 88% chance of success of your 8 missions and a 11% chance you lose a crew.

Anything which serves to reduce risk is going to be worth a great deal, not just because of the human or financial loss involved, but the political cost as well. Todays societies are totally risk averse, and its reflected in our governments.

edit: Consider this also
Image

Skylab was built on the ground and launched as one piece, with SL-2 performing some repairs to make it functional. How much time and how many cost over runs were involved in building the iss again?

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Re: The "Real Spacecraft" Thread

Post by Arioch »

anticarrot wrote:Explain please, with examples. Because we build EVERYTHING ELSE HUMANKIND HAS EVER USED out of pieces smaller than 9 tonnes.
I don't know if you followed the assembly of the ISS, which was built ~20 tonnes at a time, but it took 13 years and was a bit of a mess. Assembling things in orbit is difficult and expensive and fraught with problems. The most trivial assembly tasks have to be over-engineered (removing a plate with 10 screws on it becomes a complex task requiring hundreds of hours of preparatory engineering, specialized tools, hundreds of hours of astronaut training and practice, and up to several hours of a spacewalk). A single stripped screw can (and did) become a crisis requiring several additional spacewalks and ground crew and space crew time amounting to millions of dollars. A single dropped bolt can become a hazard that now must be tracked in its own orbit by ground control. Some problems could require additional launches to correct (when you don't have the right tool on hand).

Even on Earth, the way to lower costs in construction is to pre-assemble as much as possible in the factory and do the minimum of assembly on-site. I don't see any cost savings in breaking a spacecraft or station into many parts and trying to assemble in orbit.

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Re: The "Real Spacecraft" Thread

Post by Karst45 »

Arioch wrote:I like the RCS animations.

i think they have been around since .16 well at least they were when i buyed the game in 2012
Arioch wrote:I'm as sad as anyone about the abandonment of the DC-Y, but it was intended to lift relatively modest payloads around 9,000 kg, whereas the SLS is intended to lift payloads of between 70,000 to 130,000 kg. It's hard to build space stations or interplanetary exploration vehicles 9 tonnes at a time.
well true, but it also depend on how much your 9 tons cost to orbit.

If it 10 time less expensive then you may want to make many flight instead of one big flight.


But am being hypocrite here i tend to just launch the biggest payload i can in one shot and if it fail too many time, i split it in 2 until it small enough to go orbit.

but it more because 1: there is no money in this game yet 2: it take way too much time to dock thing for only a game 3) i like to see thing explode because of too much structural stress :P

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anticarrot
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Re: The "Real Spacecraft" Thread

Post by anticarrot »

Nemo wrote:Well, technically, the component bolts and nuts and pannels only weigh in at ounces to pounds each, why use nine tons! Thats too big! There is a cost associated with building in situ versus doing it prefab under controlled conditions.
There is a cost associated with everything. With SLS, that cost is $40B development, plus $5B per year for running LC-39. And the political impossibility of replacing it with anything else any time soon due to the sunk cost fallicy. And that's just for the 70 ton version, which isn't lunar capable, and only 20 tons more capable than Falcon 9H.
Every time you have to launch a new piece, every time you have to put those pieces together in space wearing a suit,
Stop right there. Salyut, Mir, and the russian, european, japanese and spaceX cargo capsules all feature automatic docking. You can build en entire spacestation this way without a single space walk. Mir was in fact built that way. The reason ISS wasn't was because NASA required a large amount of it had to be launched as dump-payloads via the shuttle, as opposed to russian style self assembally modules, which can be launched from medium-heavy rocket. They needed the station to justify the shuttle, otherwise the shuttle would have served no purpose.
Larger / more massive constructions will have capability and redundancy smaller units do not.
Not true. Larger constructs CAN have greater redundancy, but almost certainly will not, because useful redundancy tend to be too heavy.
Assume for a minute the same failure rate held true today.
Begging the question. Apollo failures have as much bearing on modern spaceflight as the BAC comet failures have on modern airliners. Quite frankly, if any group of engineers can't do better than 50/50 chance of survival, then either they are massively incompetent, or the mission should be scrubbed until the odds significantly improve.
Skylab was built on the ground and launched as one piece, with SL-2 performing some repairs to make it functional. How much time and how many cost over runs were involved in building the iss again?
Because the whole purpose of ISS' existance was to justify the space shuttle (which meant the space shuttle had to be essential to its construction) which is a problem because the shuttle is made from arse and failure. NASA was also never quite sure, and still isn't quite sure, what the ISS is for; which is reflected in a very long string of redesigns and its jack-of-all-trades-master-of-none nature.
Arioch wrote:I don't know if you followed the assembly of the ISS, which was built ~20 tonnes at a time, but it took 13 years and was a bit of a mess.
Well I can guess from that question that you didn't follow the development of the station that took a hell of a lot longer than that, during which time the russians built a sx module station with out encountering any of the assembally problems the americans did. The vast majority of the problem experienced during ISS construction were home-goals, though in fairness some of them were deliberate and quasi-justified. "We do these things not because they are easy, but because they are hard," so on and so forth.They wanted to spend a lot of time outside practising orking in space, so they designed construction so they'd need to.
Assembling things in orbit is difficult and expensive and fraught with problems.
I'm not talking about nut and bolt work in freefall. I'm talking about automated docking, fuel transfer, and robotics, backed up by a proper support framework.

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Re: The "Real Spacecraft" Thread

Post by Nemo »

Only 20 tons more capable? The entire Apollo service module weighed 27. This allows for much more equipment and much higher Delta V figures out of single launches.
Not true. Larger constructs CAN have greater redundancy, but almost certainly will not, because useful redundancy tend to be too heavy.
So they wont except for when they do, and you skipped capacity altogether. And berated the entire Apollo engineering team by knocking the 50/50 shot of surviving a disaster -Apollos 1 and 13, then ignored the series of concessions I made to differing engineering methods while looking at different success/failure rates and what they would mean. The true cost here is not being factored only in dollars, but also in failures. More missions is more opportunities for loss. With government sponsored space flight, the funding is wholly dependent on the will of the people to continue, to press on. Given a failure rate comparable to the shuttle the 8 missions required in the example, based on a specific complaint you made about the lunar lander, would lead to an 11.5% chance of losing one ship and all souls. We could use the Russian Proton rocket if youd like, it is the longest serving orbital delivery vehicle. 380 launches and 40 failures, 11% failure rate per mission over all. Ok maybe not. Well, its been in service since the start of the space age, things have improved, lets just use the latest block, the Proton-M. 68 launches 2 failures, 2.9% per mission which is nearly twice that of the shuttle. Need to find soyuz failure rate, I know its low.

Further, take the same auto docking methods used for Mir and apply that to Skylab. You can run fewer missions to setup a comparable skylab, or run the same number of missions and get a more capable skylab.


Everyone in the game, including SpaceX, wants better lifting capacity. Saying it should be done cost effectively is not an issue, saying that more smaller launches is superior to fewer larger launches... you run into issues.

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Re: The "Real Spacecraft" Thread

Post by Absalom »

anticarrot wrote:Unfortunately Saturn V and SLS are also very silly rockets. The former was built to win a race (very well built as it happens, but it's still a silly optimisation metric)
I've also read that it's still (even accounting for inflation) the cheapest-per-pound launch system that humanity has ever had (that might have just been for the heavy-lift market, I understand that structural design lets larger rockets dedicate a larger mass fraction to fuel, so I'd still buy into it).

Certainly cheaper than the shuttle.
anticarrot wrote:There are many ways to give NASA more capability, but almost none of them require the LC-39 launch complex that those 20,000 jobs revolve around.
A rebuild might be nice, but it's just about the best location in America for launches (certainly Jarvis Island, and maybe some of the others beat it, but they aren't part of the continental US), it's already granted access to a launch window, it already has pads suitable for very large payloads, it has a delivery road suitable for very large loads, and it has an assembly complex suitable for very large loads.

All in all, the LC-39 site is a keeper. It might be nice to tear most things down and rebuild with better facility designs, but that's it.
Mikk wrote:(talking about SpaceX)Considering how safety concious (despite driving perhaps the most competitive launch price for a new rocket family yet (that I've been able to find anyway)) that particular rocket manufacturer is, betting on catastrophic failure on their next flight doesn't seem like the good choice.
I don't know, with their previous history it's possible that they'll have some sort of launch failure. What I wouldn't count on is a failure to learn from any failures that they might (or might not) have. They've shown pretty well that they aren't stupid.
Mikk wrote:As for the usefulness of resurrecting Saturn technology? Well, those things weren't engineered to be cheap either.
And yet the shuttle still managed to be more expensive. Good job NASA!
Mikk wrote:Whether we believe them or not, SpaceX is claiming to be on the crusade to develop cheap, safe, marinized and reusable (Merlin 1C or 1D (I forget which) have been claimed to be useful for up to 20 launch test burns) launch vehicles, and re-entry cargo return vehicles. NASA certainly seems to be buying their sales pitch.
They're probably pretty serious. There's potentially a good amount of money to be made in space launches, especially if what I've read about the cost actually being dominated by launcher costs is true.
Mikk wrote:Orion crew capsule is probably going to beat the DragonRider to the first manned flights tho. We'll have to wait and see how well the ideas for Dragon-derived robotic missions other than cargo-ferry will work out as well.
If they can launch the Orion capsule then it won't be such a big deal, since the "big" market for manned Dragons will presumably only come with the commercial space travel market, which is still a little ways off.
anticarrot wrote:A launch vehicle should be designed to put stuff into orbit as cheaply and reliably as possibly. The SLS was required to use components from the shuttle; a launch system characterised by it's expense and unreliability. There is a reason it is nicknamed the Senate Launch System.
Not entirely a reasonable complaint. One of the bigger problems with the shuttle was the requirement that it support use for polar orbits. If not for the extra weight required to support that it might have been very successful, and even less accident-prone. I've heard that was the only reason why it needed those ceramic tiles, too.
anticarrot wrote:
If you want to put large payloads in orbit, then you need some kind of reliable, low-cost heavy lift rocket.
This is an error. Large and heavy are not the same thing. Size pre deployment and post deployment can also very by an order of magnitude. But beyond that... What payload are you thinking of that cannot be broken down into 50 or 30 ton pieces? And that's a question even NASA can't answer.
Probably volatiles for the forever-desired Mars mission. It's cheaper to launch them in as large a mass as you can, since that allows you to use the least possible container mass. You can divide it up into more containers, but then you're only increasing the mass that you have to transport into orbit.
anticarrot wrote:Here's a challenge. Sit down and do the maths and work out how much useful payload your choice of upper stage can softland on the moon from lunar orbit. It'll be far in excess of NASA's severely self-censored dreams. We don't need custom hardware for every single application. One patch of vacuum is completely identical to another patch as far as a rocket engine is concerned.
Actually, I wouldn't want to use an upper stage for a moon landing unless I'd had a hover-test demonstration. Balancing on top of the rocket like that is potentially a very touchy operation, so you want to be certain that the rocket itself can handle it.

Beyond that, yeah, that's a stupid complaint. If it can't be launched by your current rockets then redesign it to be assembled in orbit at the ISS from multiple pieces. You were intending these to be in-space replenish so that we wouldn't have to keep launching them, right NASA? Oh? Well, never mind.
anticarrot wrote:
Neither a spaceplane nor a DC-Y could fulfill this role.
The DC-Y wouldn't need to launch a lunar lander. The DC-Y could BE a lunar lander (with 30 tons of cargo) via direct-return, aerobreaking and an orbital fuel depot. That would take about 40 launches (mostly for fuel) which wouldn't be a particular problem for DC-I if it functioned as advertised.
I'd personally want to strip extra bits off, and ONLY use it as a moon lander/launcher, but that's just pedantry (I think that's how it's spelled...).
anticarrot wrote:
It's hard to build space stations or interplanetary exploration vehicles 9 tonnes at a time.
Explain please, with examples. Because we build EVERYTHING ELSE HUMANKIND HAS EVER USED out of pieces smaller than 9 tonnes. Sorry, but this claim really don't hold water, and it's immensely frustrating to see it repeated over and over again.
In essence, if you can launch the whole thing at once then it's as easy as it can be. If you just have to fill it's tanks after it's up, that's just about as good. The more work you have to do in space to make it usable, the worse. Thus, heavy-launch rockets are better for the "exciting" jobs because you can do more work with less effort.

Once we get space-based construction going this won't be important any more, but we don't actually have that stuff yet.

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Re: The "Real Spacecraft" Thread

Post by anticarrot »

Nemo wrote:Only 20 tons more capable? The entire Apollo service module weighed 27. This allows for much more equipment and much higher Delta V figures out of single launches.
Not true. DeltaV is dependent on technology and mass, not just mass. 50 tons and SEP gives you better mission performance than 70 tons and chemical rockets.
So they wont except for when they do, and you skipped capacity altogether. And berated the entire Apollo engineering team by knocking the 50/50 shot of surviving a disaster
Okay, you're starting to blurr your topics together. In order:
1) Imagine two capsules. One twice as big as the other. Both get hit in the heatshield by an equal size and shape meteor. The crew survive intact in both cases, but can't reenter. Being twice as big and twice as heavy does not save the larger capsule. Useful redundancy almost always masses too much to be considdered for traditional space missions.
2) That was your figure. I assumed you were refering to NASA's private estimate for Apollo 11's chances of surviving the mission a all. We are not in a race. National pride is not at stake. Such low odds should not be tollerated.
3) NASA engineers and contractors do and say some pretty stupid things sometimes. Pretty much the only reason they don't do it more often is because the politicians who hold the purse strings, and the managers who brown nose them, generally get there first.
-Apollos 1 and 13, then ignored the series of concessions I made to differing engineering methods while looking at different success/failure rates and what they would mean.
Insisting that we've made no safety and reliability advances since the 1960s is not a consession.

If you want to talk about failure rate, let's look at the most important example: Soyuz. Nine soyuz varients have flown a total of 906 missions with 25 failures, for a 97.25% reliability rating.

If you want to talk about size of luna landing, you've already lost. And completely failed to understand my posts into the bargin. My complaint about Altair isn't that it's too big, it's that it's too small. Or rather it's useful cargo capacity is very small in comparison to its size. We can build much bigger or much more efficient by using refuelable upper stages. Much much better. The 300 ton lander described here would require twelve flights, none of which would require crew. BAsed on soyuz, there's a 30% chance one will fail, but since we're not flushing $90B down the toilet over the next decade, we can afford a few cargo failures, and since we're launching regularly, there will always be a new and shiney butterfly to distract and entertain the viewing public.
We could use the Russian Proton rocket if youd like, it is the longest serving orbital delivery vehicle. 380 launches and 40 failures,[/quoote]See above. Your google fu needs practice. And since garbage in garbage out, your conclusions are flawed.
Further, take the same auto docking methods used for Mir and apply that to Skylab. You can run fewer missions to setup a comparable skylab, or run the same number of missions and get a more capable skylab.
But if you have autodocking, why do you need to put things up in 70 ton pieces? Especially when doing it that way costs ten or twenty times more. If we were talking about something like SeaDragon, I might agree with you, but the LC-39 complex is a dinosaur. It's old and sick and really expensive, the refusal to abandon it is a millstone around NASA's neck. When you're talking billions of dollars, ten or twenty times more is not pocket change.

Predicted realworld costs for SLS based on launch rates (NOT including development costs):
Once per year: $5.5B
Twice per year: $3B
Three times a year: $2.2B
Six times a year: $1.3B
Worst case mass equivolent annual launch-costs for F9H are roughly $200M, $360M, $480M and $720M.

If we had infinite funding, or even one percent of US GDP as some space advocates would like, then sure, why not. Run SLS and F9H side by side. But we don't. Given NASA's current or predicted budget, the extra capacity offered by SLS, or even later more capable versions of the SLS, simply doesn't justify its cost. Not when the diference is that big. All the "Yes, but..." in the world won't change that.

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Re: The "Real Spacecraft" Thread

Post by anticarrot »

Absalom wrote:I've also read that it's still (even accounting for inflation) the cheapest-per-pound launch system that humanity has ever had
That pretty much my understand too. Apollo though was one of the most expensive manned spacecraft ever designed. There are many 'what might have been' designs for rationalisations of the two, of which the most famous is INT-21 which launched Skylab. Imagine something vaguely like an SASSTO with 9 engine S-II pop-up booster stage. That could have produced a fully reusable (wingless) shuttle back in 1975. :(
A rebuild might be nice, but it's just about the best location in America for launches
Ah. To clarify... LC-39 is the big building where they build the shuttle, and the two (one functional now) launch pads, and support equipment. Kennedy Space Centre is the facility that contains more launch pads than just LC-39, and I agree it is the best place in the continental United States. Theoretically though, the equator is the best place to launch rockets, irrispective of where they're going. But within America, ther are many other places you can launch from. All you need to do it surround ourself with a few miles of farmland, a fence beyond that, and tell farmers there may be a handful of days when they're not allowed access to their crops. :P
Mikk wrote:I don't know, with their previous history it's possible that they'll have some sort of launch failure. What I wouldn't count on is a failure to learn from any failures that they might (or might not) have. They've shown pretty well that they aren't stupid.
Major failure points are side booster seperation, and pretty much everything to do with the cross-feed system. I assume they'll be testing both systems into the ground, but yeah, something could still go wrong.
Not entirely a reasonable complaint. One of the bigger problems with the shuttle was the requirement that it support use for polar orbits.
To be completely pedantic, the three things most directly responsable for the shuttle's 'failure' was the requirement to return to Vandenburg after a single polar orbit, to carry thirty ton spy satellites into orbit, and Nixon's decision not to spend money on a project his successor would claim credit for (when it become operational.) NASA should have stuck to its guns and come to a compromise to develop a proper shuttle over a longer period of time. But they didn't.
Probably volatiles for the forever-desired Mars mission. It's cheaper to launch them in as large a mass as you can, since that allows you to use the least possible container mass.
Except it isn't. :P In real world terms, launch costs are strongly affected by development cost and launch facility cost. See the numbers in the post above. While big dumb boosters are theoretically cheaper, their over-sized launch sites can easily offset any such savings.
Actually, I wouldn't want to use an upper stage for a moon landing unless I'd had a hover-test demonstration. Balancing on top of the rocket like that is potentially a very touchy operation, so you want to be certain that the rocket itself can handle it.
... Um, you realise that anytime the engine fires you're 'balancing on top of the rocket'? ;) Stability isn't the issue. A bigger bugbear is throttling capability. My 300ton linked above HAD to be that big, because the stock merlin engines have limited throttling, and by design it had to veigh slightly more on landing than the minimum stable thrust. Realistically, you'd want to use a custom built upper stage, modded for refueling, long term endurance, deep throtling, and a few other things.
anticarrot wrote:
Neither a spaceplane nor a DC-Y could fulfill this role.
The DC-Y wouldn't need to launch a lunar lander. The DC-Y could BE a lunar lander (with 30 tons of cargo) via direct-return, aerobreaking and an orbital fuel depot. That would take about 40 launches (mostly for fuel) which wouldn't be a particular problem for DC-I if it functioned as advertised.
I'd personally want to strip extra bits off, and ONLY use it as a moon lander/launcher, but that's just pedantry (I think that's how it's spelled...).
Tempting as that would be, you'd want to deorbit it every now and then for major servicing and repair.

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Re: The "Real Spacecraft" Thread

Post by Absalom »

anticarrot wrote:
Absalom wrote:I've also read that it's still (even accounting for inflation) the cheapest-per-pound launch system that humanity has ever had
That pretty much my understand too. Apollo though was one of the most expensive manned spacecraft ever designed. There are many 'what might have been' designs for rationalisations of the two, of which the most famous is INT-21 which launched Skylab. Imagine something vaguely like an SASSTO with 9 engine S-II pop-up booster stage. That could have produced a fully reusable (wingless) shuttle back in 1975. :(
For that matter, if NASA had continued developing that lifting-body escape pod for the ISS from the 90s then THAT could have transitioned into (at least the crewed portion of) a proper shuttle.

Shoot, if anyone on this forum had access to a sufficient fraction of NASA's budget then we could probably manage our way to a usable one. Personally, I'd prefer a HTOL design in the form of a conventional aircraft layout (according to this, it's easier to adjust balance in them), with a drop tank (ala Lockheed Star Clipper), the drop tank itself being equipped with a jet engine and slew wing for a remote-controlled return flight (ala Baikal, though you could just throw the drop tank into the ocean as well). The flight profile would be roughly the same "get up there, and push the booster & payload out" one as SpaceShipOne/WhiteKnight, except that the WhiteKnight-analogue would only have a weak engine that might not even have enough power to keep it in the air; after all, it would just be for retrieving a mostly-empty fuel tank from a high altitude, so even if the engine can't do the job you haven't lost nearly as much as you could with some designs.
anticarrot wrote:
anticarrot wrote:The DC-Y wouldn't need to launch a lunar lander. The DC-Y could BE a lunar lander (with 30 tons of cargo) via direct-return, aerobreaking and an orbital fuel depot. That would take about 40 launches (mostly for fuel) which wouldn't be a particular problem for DC-I if it functioned as advertised.
I'd personally want to strip extra bits off, and ONLY use it as a moon lander/launcher, but that's just pedantry (I think that's how it's spelled...).
Tempting as that would be, you'd want to deorbit it every now and then for major servicing and repair.
You might, I'd want to keep the frame in orbit and just haul parts up to the ISS with the OTHER side of the launch system (I never said that the moon DC would be doing all of the work, and I personally believe in this version of "staging" ;) ).

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Re: The "Real Aerospace" Thread

Post by Arioch »

The US Navy today conducted the first launch of a full-sized unmanned aircraft from a carrier today.

http://news.yahoo.com/u-launches-drone- ... 52636.html

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Re: The "Real Aerospace" Thread

Post by Charlie »

Arioch wrote:The US Navy today conducted the first launch of a full-sized unmanned aircraft from a carrier today.

http://news.yahoo.com/u-launches-drone- ... 52636.html
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Americans in particular, as with most people, hate the idea that a machine can decide if a person will live or die, to that end I suspect these will be operated much the same as the MQ-9 Reapers. I suspect that for the time being kill strikes and orders will still be a purely human matter, at least until people are fairly comfortable with more autonomous drones. After such a time when targeting validity is good enough that the drone could reasonably decide for itself weather a bunch of kids with sticks are noncombatants or not, I think we will see human overwatch for a long time in coming. Still a bigger badder Reaper could be a good thing, they have proven effective in long range precision strikes.
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Arioch
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Re: The "Real Aerospace" Thread

Post by Arioch »

Even as drones become more autonomous, I think external rules will still require a human operator in the loop when it comes to weapons deployment. Which only makes sense; it's hard to imagine a situation in which you would want a drone to acquire and attack targets on its own without a human controller giving the okay. Such aircraft are still fairly expensive, so somebody is going to need to be watching them (even if it's only a single controller managing a whole fleet of drones) and waiting a few seconds for authorization to fire is not likely to be a serious problem.

My concern is more about the potential ability of technologically sophisticated opponents to jam, confuse, or hack an armed drone.

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Re: The "Real Aerospace" Thread

Post by icekatze »

hi hi

The use of unmanned drones, and really the use of air strikes as part of peacekeeping operations at all, is a serious problem. It has been a little while since the United States has been on the receiving end of an occupying power, but a lot of people fought and died for due process. Blowing someone up and everyone around them because they look suspicious is certainly a noteworthy development in international justice.

But from a purely technical standpoint, using unmanned aerial vehicles as opposed to manned ones is really a no-brainer. They don't have to worry quite so much about things like fatigue or G-forces.

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Re: The "Real Aerospace" Thread

Post by Karst45 »

Charlie wrote:
After such a time when targeting validity is good enough that the drone could reasonably decide for itself weather a bunch of kids with sticks are noncombatants or not,
Well even human were not always good at deciding if what they saw were combatants (enemy) or not. I think we had more of our soldier killed by friendly fire than by the enemy itself (that also include used / defective submarine)

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Re: The "Real Aerospace" Thread

Post by Arioch »

Karst45 wrote: Well even human were not always good at deciding if what they saw were combatants (enemy) or not. I think we had more of our soldier killed by friendly fire than by the enemy itself (that also include used / defective submarine)
Friendly fire incidents (and collateral damage) will always happen regardless of who is making the decisions, as long as there is limited information on the battlefield, but I don't think they even come close to other kinds of casualties. (Unless you were referring to the Canadian military... in which case I suppose friendly fire is perhaps the only way to get killed. :D)

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Re: The "Real Aerospace" Thread

Post by fredgiblet »

I didn't realize that he was Canadian until just now.

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Re: The "Real Aerospace" Thread

Post by Absalom »

Arioch wrote:My concern is more about the potential ability of technologically sophisticated opponents to jam, confuse, or hack an armed drone.
My understanding is that jamming the com-link at critical points in all current US combat drones initiates a "return to base" behavior. Which certainly does open up a potentially simple defensive tactic, but I believe that treaties normally provide a window to wrap up ongoing operations (otherwise any treaty signed while an urban battle was progressing would be almost certain to be invalidated before the combatants could withdraw), so you could simply locate your "last chance" zones in unpredictable areas. As for terrorists & other mobile targets, they're almost guaranteed to either not have jamming equipment active, or to not pose a major risk of collateral damage in the presence of a major control delay.

As for confusion, there's GPS (which gets us back to jamming), terrain following (likely radar, so jamming again), and maybe image recognition (what are they going to do, cover their trucks with E-Ink displays?) that can be played with right now, but everything else will have to wait for the technology to exist before it can be confused ;) .

As for hacking, it really shouldn't be a problem, but admittedly I've read somewhere that some of the mid-90s designs use sub-par (in this case, no) encryption on some of their data streams. The expensive stuff, fortunately, will surely be designed to resist Chinese hackers, and therefor have all allowable data streams encrypted (so, any flight beacons would be unencrypted, but beyond that...).

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Re: The "Real Aerospace" Thread

Post by Charlie »

Arioch is right, final strike orders will human ones for a long time still. I often wonder weather it was movies that made people afraid of machines like that. ED-209, HAL 9000 and other robots come to mind. Are people naturally afraid of machines that can replace them or decide to remove them with force? Is it hard coded it us?

In regards to collateral damage, It doesn`t bother me in the slightest when a school, church or hospital is blown up, so far, far away. War is War, accidents happen and mistakes are made. People often say what if it was you that was blown up? I always say that it is not me. Moral values aside, as technologies progress the occurrence of friendly fire and miss strikes will be lessened.

I'd like to see far more drones of the future battlefields, at the very least it would be another set of eyes for the common soldier. I don`t think drones will ever replace the human element in war for a very long time.

Canadian Snipers have the second and third longest kill shots in the world, by a sniper.

As for hacking, I really don`t think it would be that easy for a military system to be hacked, even by a another military power. If it were so, it would have already been done. Further more, current drones are not based on a centralized system. As far as I know, they work the same as the E.O.D drones, each is slaved to a single computer system. Also, if it is possible to control the drones externally, you would only be able to control the battle ready drones in the air. At the moment, drones must be prepped the same as manned aircraft, on the ground by humans. I guess it is possible to fabricate the orders and authentication. Still the damage that say ten fully armed drones could do is less than a smuggled or homemade low yield nuclear explosive could do.
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