Posts by John Smith 19 16330 publicly visible posts • joined 10 Jun 2009
*If* I'm reading this right then
1) You can't bury a monitoring clause in a 50 page T&C
2) It has to be a *specific* opt in where you *request* to have your internet access monitored.
This should stuff Phorm in *future* but the view of the CPS and ICO remains they were gutless.
*Grudging* thumbs up because that is what the response of the CPS and ICO has been.
Grudging.
"My reference was to the gun, i didn't emphasise this in the post."
My apologies for the suspected troll. *That* makes perfect sense.
That said IIRC the USAF at Holloman (home of the crash test dummy) did a rocket sled test that hit M5, but the last couple of M numbers were in a plastic tent filled with Helium to cut the drag. I think it was on a Discovery channel documentary. Impressive to watch but the tent was a write off afterward and I would not want to be *anywhere* near it once it started moving.
Adequate for getting a scram jet started but now you've got the *whole* atmosphere to get through without vaporizing the vehicle.
I like a big gun as much as anyone but the heating aspect is (I suspect) a bit under recognized as a problem by their supporters.
I've only commented on the bits I disagree with. The rest you can presume I go along with.
"Air is taken in at the front of the SABRE and almost instantly cooled down to the point at which it is almost liquid, using terrifically powerful freezer kit employing a liquid-helium loop."
And driven by a pair of oversize liquid Hydrogen tanks. A very cold thing makes a fairly warm thing substantially colder.
>>The supercold air takes the place of liquid oxygen in the combustion chamber, reacting with liquid-hydrogen fuel to produce thrust in much the same way as the space shuttle main engines. Heat sucked from the intake air is dumped into the fuel.<<
The amazing spaceplane is expected to be able to repay those big investment cheques, as it will be able to deliver payloads – admittedly, at first quite small ones of only 10 tonnes or so compared to its own substantial mass of 275+ tonnes – at low cost.
That's a payload which is c3.6% of GTOW. In the launch biz that's pretty good.
It's better than a Delta IV and on a par with an Atlas V. This counters the traditional whine that SSTO's can't deliver as much payload (as a portion of GTOW) as expendables.
The shuttle manages about 1.25% of GTOW. It has an SSTO payload fraction *without* the actual benefits of SSTO.
REL's engineers have been compelled to shave everything to the limit to produce a design which seems to show that SABREs and the fuel they need to reach orbit can fit into a re-entry-capable airframe along with some cargo.
In a word. No.
The ceramic aeroshell is to be just 0.5mm thick.
Slightly thinner than some part of the SR71 wing structure (which were *also* corrugated BTW).
Skylon's skin is only designed to carry the *thermal* load. Mechanical loads are carried by the geodesic truss framework. The technique was proposed for the X20 DynaSoar.
The undercarriage has had to be lightened too,
Below *common* state of practice, *not* state of the art as far back as the late 1958s (and not a CAD/CAM workstation in sight).
"so that a Skylon won't be able to land on just any runway"
Wrong. This thing might take off like Michelle McManus but it'll land like Britney Spears. Weather or not it'll be *allowed* to use ordinary airports, as it is technically a UAV, is something to be thrashed out.
" – it will need a special reinforced one able to cope with heavily loaded wheels moving rather fast."
On *takeoff* only.
If the craft itself should gain just a few per cent in fueled-up weight during the development process, this would wipe out its entire payload margin.
No. SSTO's are vulnerable to growth in the *dry* weight. In principle the wings make it *less* vulnerable in this area than vertical takeoff designs.
"There are those who would argue that operations using liquid hydrogen fuel will simply never be economical:"
Mostly they argue its a pig to handle. Liquid oxygen freezes out water on top of the insulation if it's not good enough. Hydrogen liquefies *Oxygen* out of the air.Insulation has to be *very* good. It's a PITA.
However *all* alt-space advocates agree the fuel cost is "In the noise".
The *real* cost is the manufacturing and "standing army" of managers, safety inspectors, managers of safety inspectors, document management team etc. Cost is strongly proportional to *complexity* and *weakly* proportional to size.
" the stuff takes up so much room that hydrogen aircraft – including the Skylon – are always made up mainly of fuel tanks."
*All* launch vehicles are mostly fuel tank.
" It is so troublesome, potentially dangerous and expensive to handle that it will infallibly destroy any business model based on it other than that of government-funded military or scientific projects."
No.
Regarding RE's business model it's *strictly* for profit.
They build a vehicle. It's up to *other* people to operate it.
It's like building a taxi. Someone *else* operates it. If they don't make a profit *they* go out of business. Just like a *real* transport systems, not the insane 1 shot ticket-to-ride/govt cost++ system expendables foist on the users.
TBH there were a few moments when I was tempted to flag the article as Troll.
If this is Lewis on a subject I know something about what is he like on subject I don't know anything about?
<sigh> There goes my shot at the Reg spaceplane desk.
"To achieve orbital velocity 17,500mph (LEO, Mach 25), launching from the surface of the earth it would need to go much faster due to aerodynamic drag, say Mach 30."
True.
"At Mach 25 or 30 no material would be able to withstand the temperatures induced due to the aerodynamic drag and would destroy the craft before it go anywhere near orbit."
I was tempted to call troll on this but I think you misunderstood the animation.
First the fact Shuttle manages the process in *reverse* should tell you that with appropriate design and materials a vehicle can (and has repeatedly) survived this regime intact.
Skylon uses atmospheric Oxygen to accelerate to cM5. During that time it's climbing *continuously* and outside air pressure is dropping like a stone. Switchover to full rocket drive happens when it's *above* the bulk of the atmosphere.
It's not actually *flying* by aerodynamic lift. It continues to climb because it's kinetic energy is increasing and the equilibrium altitude where it is balanced by the Earth's gravity field is higher. Think Newton's analogy of a cannon on a mountain. A faster cannon ball is (on an airless planet) equivalent to a higher mountain. An *accelerating* cannon ball is like a cannon mounted on a continually rising platform.
2 things.
Those big red things at the start of the animation are the Hydrogen tanks. Its density relative to water is 7-7.7%, depending on how densified it is. It's big but *light*.
You might also check the *real* dimensions on this thing.
IIRC Takeoff and landing speeds are high. Part of their work has been designing a light weight braking system that borrows (of all things) from truck racing technology to use water cooled brake. Note the undercarriage weight is "light" relative to the *common* state of practice, not the state of the art. Landing gear weighing 1.5% of Gross landing mass (for airliners it's more like 4%) were flying in the 1950s and 1960s, specifically on the B58 Hustler.
As for "Barely manouvre" it depends how much you *need*. The tail fin + forward cannards should give aircraft like behavior but throttling the wing tip engines would give significant yaw capability. It might *look* a bit like an SR71 but conceptually its mission is *much* simpler. More or less in a straight line is fine.
"The problem with the Shuttle was that it was never really developed beyond it's original configuration."
True
" Not that it was actually a bad idea to start with"
The idea of a *reusable* (as in minimal maintenance, refuel, replenish and reload another payload then launch) is a good idea.
It's *implementation* was a *very* bad idea.
"You can't comment on a technology when you don't understand it."
Excellent advice. Rarely taken in practice.
"I hope the "chill out" technology doesn't slow down the incoming oxygen atoms to any great degree."
That's *exactly* it's objective.compressors work best at about 1/3 to 1/5 the speed of sound. Cooling the air "shrinks" it and allows the compressor to only need to operate well over a *relatively* narrow air speed, rather than the full M5+.
"There is definitely going to be some energy transfer to the cooling apparatus. "
Which is used to drive the compressor fan and the Hydrogen turbo pump in the first place.
"How do they intend to counter the drag from doing what they do to the incoming air?"
By doing it to as little air as possible at any stage of the flight. The inlets close as it speeds up and the rest is bypassed around the engine. Rather like the J58 installation on the SR71 in fact.
"Discarding "pieces of technology" actually makes sense if the technology costs less than all the extra stuff needed to make the payload carrier re-usable."
And you don't mind needing a massive firing range to deal with discarded parts falling out of the sky and/or you don't design *in* reusability from day 1.
"And in the end, what is the point of "coming back in one piece"? "
Eliminating the costs of recovery and re-integration. But that only counts if you're reuseable. Keeping the tanks (*especially* if they have LH2) makes for a large but "fluffy" vehicle with *very* low mass per unit area. This (in principle) give a slow relatively low temperature descent, it's also how some of the Shuttle's internal tanks survived to the ground in 1 piece during the last Shuttle breakup.
"Getting to orbit is hard, getting down is a lot easier, since the atmosphere is helping."
You've either got that backwards or severely underestimate the re-entry problem. consider how many countries have launch vehicles (up mass) versus how many have down mass capability in *routine* use.
You can do it in a capsule, which ought to be the preferred method.
You can do it in a capsule and historically it *has* been done in a capsule.
Except for the Shuttle, which wasn't.
Shuttle is the *only* data point of the winged landing type (Except for the sole Buran landing) to have flown repeatedly. With one data point you can extrapolate *any* curve you like.
"The US decided to build a reusable space shuttle. "
NASA needed something to keep its research centres occupied. Shuttle was the only part of the programme Nixon permitted.
"but discovered that it needed a LOT of maintenance between flights"
Hardly The budget profile virtually *guaranteed* they'd sacrifice maintainability and operations costs over up front costs from day 1. The only "discovery" might have been that bonding a ceramic with 1/3 the thermal expansion coefficient of aluminium and then giving the sandwich a 1000c temperature gradient *might* cause a bit of a problem.
"And yes, I know the space shuttle is only mostly reusable "
No. The space transportation system is mostly *refurbishable" with lots of work.
Most of what you "know" is incorrect. What you don't know is also substantial.
You might find a bit more history would be useful.
"The shape looks like its straight out of the 60's, and more than a little reminiscent of the SR-71."
Actually the planform looks like the AV Roe 730 M3 reconnaissance bomber of the 1950s (wing tip rather than mid wing engine pods and cannards rather than chines)
I'd guess the design team has better access to 730 design data than SR71.
Note they have stated they are planning a design review to "D" standard which might change things.
"It's partly historical accident, launching from Florida, but the Shuttle had an awkward gap between being unable to return to KSC and being able to abort to a runway in (I think) Spain. "
No. The Shuttle has various abort modes. They transition into each other. there is *no* gap. The most dangerous part of the flight are the roughly 2 minutes from launch to SRB separation. It's just assumed the stack stays together until they burn out. Note that most abort modes have *never* been actually tested (return to launch site or transatlantic abort for example).
BTW the integrated health management system NASA added to the Shuttle main engines allow throttle down, instead of just shutting the engine off. This down graded large portions of flight profiles from highly risky never been tried abort modes to to abort to orbit, which has and does work.
The first is the light weight pre-cooler or "Fractal plumbing" heat exchanger, manufactured using specially developed production techniques (and possibly machinery).
The *very* special sauce is the frost control technology which stops the thing freezing the water vapor in the air into solid ice within a few seconds of it being switched on.
Frost control is *the* dirty little secret of all deeply pre cooled (SABRE) or liquid air cycle (LACE) systems like the one that Andrews Aerospace (Alchemist?) were developing which *must* be handled in order for them to function.
If this test is a full size pre-cooler *and* includes frost control it is a *major* milestone which (if the airflow is *anything* like realistic in terms of temp and pressure range) AFAIK this has *never* been done by any of previous attempts to do such a system.
I'll comment on Lewis's inaccuracies later.
How about starting with the coding habits that *allow* heap overflow in the first place?
Or a set of macros (Can't be a subroutine call because "performance" is *so* important) to ensure check code gets inlined as a matter of course?
This is *not* a pop at MS in particular. They (like *every* development shop on the planet) want code written fast.
It's just the *consequences* of their practices ensure a whole lot *more* people get f****d than most other software suppliers.
Note the fix "Turn off FTP" might as well be "WTF did I buy this in the first place if I can't run something it says it can (in safety)?"
Thumbs up for finding this one. It's good to remember the price of security is eternal vigilance.
Perhaps a lesson to people who wants *bucketloads* of cash to counter a threat posed by not many nations. Seriously North Korea?
Who else?
Thumbs up for the success and leaving this in the inventory seems a pretty good idea but beyond that...
And it doesn't need a full spec fully loaded PC running Windows to do it.
A note on surveillance.
It's not *your* PC. It's the companies.
I do hope that the effort they can save supporting *individual* desktop users can go on making sure their network is rock solid.
network downtime -> company down time.
Have access to people's bank account details so they can verify you're old enough to gamble?
But the question is have they committed fraud *against* their users or simply fallen foul of the merkins nonsensical attitudes to gambling?
In Europe the off course or off track gambling industry is a *legal* business turning over billions in whatever currency you choose to work in. Entry to it is much like joining any large scale retail business.
In America it's a branch of organized crime.
So are these *real* crimes or just ones due to US schizophrenia on the subject?
I'd like a "Question mark" icon as I'm puzzled.
But here's a question.
Large ISP's seem to do *lots* of traffic shaping.
In order to do so they are looking *inside* those packets.
Most users don't *want* TS.
WTF can't they do something *useful* with that capability instead of just ekking out their bandwidth to slap a few more subscribers onto infrastructure that *cannot* support their existing subscribers at the bandwidth they *advertise* (not deliver)?
Thumbs up for this action but *no* to any kind of *blanket* requirement//obligation, which would be a govt blank cheque.
"Amazingly enough, 50 years after Yuri Gargarin, the Russians are again the only country able to put people in space, and NASA is paying $62 mil per Soyuz seat."
Not strictly true. China has demonstrated capability if you don't mind a hypergolic launcher like a Titan 2.
NASA *could* get human capability *if* it funds CCDev (actually it should have funded the crewed COTS option D). It is not an unreasonable attitude that until at least *one* company demonstrates ISS docking no funds should be released for crew escape system development which is what payment-by-results is all about.
I'd think the chance to knock the price per seat by say 2/3 and put US astronauts back on a US *commercial* launchers would have been sufficient incentive to do this. Instead NASA has *forced* by Congress to continue Orion development at 75% of its original level and look at the frankly nuts SLS.
I'd suggest any US based readers might like to find out what Congressional appropriations are making NASA do and consider putting pen to paper and make their feelings known to their local representative (Short, well structured, polite and spell checked can still be forceful and seems to work best).
"This is all thanks to Richard Nixon, who squashed the reusable flyback booster option, and also squashed the liquid-instead-of-solid option, and insisted on the cheap-ass solids & external tank setup, so he's basically directly responsible for the deaths of 14 astronauts."
The Office of Management and Budget's *grossly* unrealistic funding pattern really stuffed the design and made the "stage & a half" architecture (not to mention Administrator Webb's personal choice for sourcing the SRB's from a factory with *no* way to get them to the cape in 1 piece) the only *possible* way to get it to fly at all.
It did give NASA the first large capacity high performance engine *designed* for re-use in the SSME. It would be a useful building block to keep in mind for the future (especially if they incorporated the results of the various R7D programmes they've run on it over the years).
Thumbs up for your understanding, not the situation the US finds itself in.
They do store better faster.
Some of the lightest were based on the technology used in Uranium gas centrifuge technology.
Hollow carbon fibre cylinders
Rotor pattern impressed on iron based ink in the skirt.
High vacuum for minimal windage losses.
The joker in the pack is the trade off between "cleverness" factor and robustness.
Note. Wide and flat is better than narrow and tall. Faster is *better* by a lot. 2x speed -> 4x energy storage.
"I work for an aerospace company that is a sub of NASA. Glad I don't work for NASA, but it still looks precarious where I am, at least for the long term."
That depends on weather your company makes something Spacex wants or needs they don't make themselves.
If it does your company should *already* be talking to them. I don't think they are *quite* as integrated as casual observers might think.
Alternatively *you* should be talking to Spacex. Obviously this does depend on which bit of NASA your company deals with and where.
Making cross feed happen is tricky. Remember it takes 9 MW sized pumps (powered by c2% of the propellant they move) to empty each tank normally.
The obvious solution is to use 2 upside down L shaped pipes inside each tank* of *different* lengths matching up to mating no-leak couplers. The pressure difference due to the different lengths of the fluid column *should* do the rest.
The catch. You now have *two* 1st stage types to keep track of (call them Booster and Core).
How long before someone makes 2 B's and 1C? In a perfect world never of course but IRL.
Note this might be *unavoidable* if a "genderless" coupler (no male and female sides) cannot be found. while it might make what type of 1st stage you are making obvious by sight that does not preclude a mfg cock-up.
Assuming a genderless coupling is available setting up a different tank pressure (both pipes running to near the bottom of the relevant tanks) would seem to be the obvious way to go. Just change a few parameters in the flight computer. This way cross feed becomes just another *common* improvement to the basic stage. Avoiding multiple hardware configurations has worked very well for Spacex so far.
The joker here is that Spacex describe their vehicles as "Semi-pressure stabilized" (IIRC they've got patents on this) so how far they can dial up (or rather dial *down*) their tank pressures relative to each other without compromising rigidity *may* be the big issue.
I fully expect Spacex have thought through *all* of these points through, possibly adding their own little variation on solving the problem. I suspect good pressure sensors with *narrow* uncertainty ranges pay off *very* well in this application.
*The feeders *could* be made as ducts running along the inside wall (with the inside wall making up the bottom surface). This would eliminate any concerns about the pipe ends waving around inside the tanks during flight but it would require changes to *every* ring segment of each tank, adding quite a number of friction stir welds to the build process and changing the structural response by quite a lot as each tank would have acquired a rigid "backbone" one side.
while this definitely puts a mark in the sand about Spacex's future plans I'd *really* hoped for an announcement on the COTS 2 and 3 flights.
Ideally along the lines of "We've set xx/yy/11 as the date for our COTS 2 flight and NASA have agreed that subject to all parameters being nominal (*zero* drama, completely by the book) we can include the objectives of the COTS 3 flight, resulting in a docking with the ISS" (and NASA paying them the COTS 3 fee as well).
Although just setting a date for COTS 2 would have been good too (I did entertain the possibility Spacex would skip *announcing* a launch date and just do it but that lacks buildup).
This is still a pretty big statement of intent by Spacex. Musk seems like a pragmatist. I suspect they have not gone out of their way to hit this *exact* level of payload but have heard from *someone* (hopefully *several* someones) that they'd definitely be interested in a vehicle at this capability. BTW in Musk's presentation before the National Press Club on Youtube he mentions the following.
1) At 4 launches a year he expects Falcon Heavy to be able to hit the $1000/lb level on payload cost..
2) At 400 engines a year Spacex is the biggest engine maker on the planet.
3) NASA has issued Spacex a $300k Request For Proposal for how they would do a launch vehicle 3x *bigger* than the Falcon Heavy, IE 1.5x bigger than a Saturn V. $300k is not much in NASA terms but suggests *someone* is wondering what it would cost the agency to get that kind of launch capability again.
4)Musk estimates Falcon Heavy it will generate about 400 new jobs split between Macgregor Texas (where they make them) and Cape (Kennedy or Canaveral). So no love to North Alabama.
5)Dragon + Falcon Heavy could do a trip around the moon as it stands. No mention if that would be with full 7 people on board. If so it *could* make someone a profit on space tourism outside LEO.
6)Musk reminded people the TPS is rated up to a re-entry from Mars.
7)They want to upgrade the Dragon capsule to do land landings with rockets to cancel the last part of the descent velocity. Note that *should* make them powerful enough to function as an escape system in an emergency.
8)Musk confirmed they were still expecting crew carriage to take 36 months due to the escape system design.
9)Musk was asked if it could launch satellites 2 at a time (like Ariane 5 with the Speltra container inside the fairing) but he diverted the question into sub satellites and dispensers (which he expects the 1st flight *will* carry, although without a primary customer).
I felt a little bit of a let down thinking this was more or less a product announcement. Having seen the video its a good deal firmer than that and I suspect Musk has at least a few slots for the smallsat dispenser already booked out and at least one customer ready to book *if* the 1st launch runs smoothly. Might be national security, might be a humongous comm sat. Might even be Bigelow ready to launch the first space hotel.
Lots of potential.
Each Falcon 9 is meant to have full 1 engine out capability. The question would be if it had a 3 engine failure on *one* module. Does the control system have sufficient control to bring the stack under control?
Note this *should* be a very unusual situation but those corner conditions are the sort of things that nudge up the reliability.
BTW the structural efficiency of the booster rockets are *astonishing*. A mass fraction of 1/30 is *very* impressive. The Isp of the Merlin 1d engine *appears* to be enough to make the stage SSTO *even* using the sea level Isp only (which would be *very* conservative). However that does *not* include the guidance and navigation package or a payload fairing, or a payload (quite an important element for a business).
As for any Bondeque elements of Mr Musk. Well definitely a bit of Donal Pleasance vocally, but facially I'd say rather more David Walliams.
Well there *is* the other contender in the COTS programme. OSC spec'd a new launcher (Taurus II) and a capsule Cygnus and did it on the $190m left over when Rocketplane Kistler fell on their face.
Last heard acting more like a true govt con-tractor they were "negotiating" with NASA to have another couple of hundred million $, for a "risk reduction" first flight (of a *completely* new launcher, which historically have 50% failure rates) in Q3 of this year (*with* the Cygnus capsule on board) and *then* do 1 flight of the COTS series (which *presumably* will cover *all* outstanding qualification requirements in Q4 before going straight into ISS re-supply by Q1 of next year.
Provided of course any bugs they find can be fixed in the 3-6 months (depending on *where* in those quarters the flights fall) between flights.
Competition is *always* good but you have to have at least *one* other player in the game and OSC look more like they are doing a lock-mart with the X33.
"Thanks for the cash guys, sorry we couldn't meet the spec (like we said we could) but unfortunately <insert series of plausible excuses> so we just couldn't make it work.
Do you mind if we can keep the rest of the cash. Thanks, it's what our stockholders would have wanted."
I'd *really* like to be more positive about OSC but they've promised a *very* complex design (relative to Falcon) for less than 1/2 the design cost and outsourced a hell of a lot of it and then *whined* they'd need more money to make it work.
Their timetable is here
http://www.orbital.com/TaurusII/files/Feb_Milestones.pdf
You appear to have been hitting the caffeine a bit hard there. Probably best take a few deep breaths. BTW spell check is not enough. I've usually regretted not doing a read through before posting (you might like to read my comments the Saturn V and work where my reasoning went haywire). However...
"(Plus lets not forget, NASA are still very much and have always been partly US military (the government PR people downplay that side of NASA, but they are very much still military) "
Well the "A" in NASA is for aeronautics. Actually given the trouble Shuttle gave the USAF they try to keep *well* away from most of the rocket parts.
You're right about politicians. Apollo was *all* about the proving the US could do what the USSR could not. There was *no* long term development plan after that. That's why Saturn V production shut down in 1968
".. (but it would have been a lot cheaper without all the bureaucracy and government delays!) "
Err cheaper possibly. *if* a multi-millionaire *like* Musk decided he wanted to have a go. Otherwise 100% of *all* flights that have reached orbit have been on some governments dime/centime/cent or whatever the unit for a part of a rouble the USSR used.
"Oh we can't do anything to annoy the US and competing with them annoys them and so we can't compete with them, but oh we can give them our money,"
You might like to look up the Suez crisis of 1956 to see a key item that *really* shaped US/UK/French/Israeli relations ever since. In the aerospace context you might also like to look up BAe and the Multi-Role-Capsule.
"don't even get me started on the UK government's attitude to space exploration which makes my blood boil, especially when I see news like this "
I think readers may have detected your slight dis-equilibrium on this point.
Regarding HOTOL things are changing. The senior civil servants who thought of it as "Concord 2" (you'd have pry government funding out of their cold dead hands) are mostly dead or retired and a slightly different attitude exists.The conversion of BNSC from an outfit forced to run a space theme park in Nottingham to an actual "Agency" with its own *budget* (albeit a not very big one) is actually remarkable. It's only taken 25 years but better late than never.
BTW Reaction Engines don't *want* government money and have stated *all* along that their costings are based on commercial investment and return. They want UK government *support* not cash. This is why their project is (unless you're familiar with the size of modern capital invesment projects like air liners or the Channel tunnel) *huge*.
"With HOTOL and its successor Skylon, we could have had runway launch capability like a normal aircraft up into low earth orbit and do it for a fraction of the current costs"
It still *could* happen but RE will either become the engine maker or be absorbed into an airframe maker. No one buys a Pratt & Witney or a Rolls Royce airliner. They buy Airbus or Boeing.
"Between SpaceX and Scaled Composites they carry a lot of hopes and dreams so to speak, "
You might like to include Bigalow (who want to build orbital hotels and Virgin, who want to *start* with sub orbital flight.
"We need companies like them to bypass the politicians because the politicians are not focused on helping us, they are only really interested in helping themselves"
Actually both those companies are very much in it for the money. However they believe there's *more* money from servicing a *much* bigger market that trying to get what they can out of governments as space con-tractors tend to.
Note that NASA believed there was *no* market for space tourism. Virgin Galactic took (IIRC) 5000 payments at their *full* ticket price of $200k in their first *day*.
NASA does not do market research very well.
"So I really hope SpaceX succeed in all they try. They really are an inspiration."
Then you should either join them or consider how best to earn the kind of money needed to actually *go* into space (albeit for a short time).
What Spacex, Bigelow and Virgin have in common is the view that space is a *place*, not a programme that *only* governments can do. Something to keep in mind.
"The Moon also has no protective magnetic field, so staying there for a while will produce useful info on how the human body responds to solar radiation, "
It does however have *lots* of soil, which is what any smart moon base would be either be buried under or stuffed in a cave. Not very cool, but very practical.
"The sobering thought is that most of the people who designed Saturn are either long retired or dead, so a lot of the expertise has gone with them."
You forgot the supply chain for *most* of these parts.
Companies out of business.
Companies merged and records dumped.
The last estimate for a re-start on the J2 engine line was c$2Bn.
The *actual* problem with a re-start would be drawing (and *enforcing*) the line at which you make changes. Get new mfgs in? Almost certainly. Change materials because SS grade XX is so *old*? I'd suggest not. The position would likely be less clear on the telemetry and computer systems.
Spinning metal inertial driven by 200lb GN2 tanks?
BTW the "Instrumentation Unit" on the SV weighs about the *same* as the Vehicle Equipment Bay on the Ariane 5 *Despite* the A5 being just over 1/2 it's diameter, and the VEB is made in carbon fibre.(Laser gyroscopes + batteries are also substantially lighter than spinning metal + large GN2 gas canisters).
I think a working theory of the tax thresholds under NuLabor were basically set to ensure that NotW and Sun journalists would be kept sweet.
Wouldn't want any of the Diggers merry men upset about supporting Tony Blair.
BTW Merkins who think their journalists are noble seekers-after-truth should be aware of where the National Enquirer recruits from.
In amongst the orgy of lets lets-see-how-many-cores-we-can-stuff-on-a-chip I wondered when *someone* would recall that.
Something to keep in mind.
Simple example. You have 48 cores on a chip.
Have you got 48 *address* buses to match them?
Interleave *48* address requests with *minimal* (I don't believe that many execution paths could interleave perfectly) gaps?
48 (or 96 or more) memory planes to match them?
You might like to try getting your hands on a little book called "Thrust into space." It discusses the energy requirements for various missions and (can't remember if it says so specifically) the molten salt reactors for the nuclear aircraft programme were the proposed solution to this.
Note the nuclear aircraft (and project Pluto, the nuclear ramjet at Los Alamos) use ambient air as the working fluid. NERVA would have heated the 20k LH2 through its outlet nozzle to heat up but I'm not it would have gotten as far as 0c before hitting the 2000+c core.
One of NASA's side projects was an electrically heated Hydrogen thruster.
They appear to have built the world's largest incandescent light bulb filament at 30Kw.
The design gave 1lb of thrust but at an ISP of c500sec (The smallest thrusters on the Shuttle are 25Lb with an ISP of 215secs).
Obviously a scale up would be needed but if you have MW sized power generation this should be fairly straight forward.
Tapping some hot H2 off the core of a nuclear thermal system would be a bit more problematical. The smart money would carry LO2 and keep the propellant system unified with the option to refuel at Mars from in situ resources (AFAIK no one has looked at in situ mfg of storable propellants or oxidisers and NTO and the MMH/UDMH groups are all *nasty* to handle).
ISDN#
Good one. I'd forgotten that.
That said it was a pretty clever solution (No peak bandwidth but *solid* all the time).
Could the internet have exploded at a rock solid 155kbs? We'll never know.
ISDN's failures would seem more a regulation and national telco's failure rather than a technology fail. DAB looks to have *all* 3.
I still like the VHS/Betamax analogy because it's more consumer based and media consumption (what people *could* view and what they *wanted* to view) was a pretty big part of the success and fail balances.
Except DAB+ is *better* than DAB.
And U&K broadcasters won't admit they got hit with "Early adopter" syndrome. Sure all the receivers would have to be junked but is the modern digital broadcast chain *that* inflexible it could not be upgraded?
I note similarities to the enthusiasm for satellite Vs terrestrial TV in UK and the continent.
UK. Broadcaster develop repeater-station-in-a-suitcase and set up little shed around UK giving c95% coverage?
European broadcasters dream of spewing their dubbed US soaps across the whole continent and buy satellites *despite* the regulatory situation being completely fragmented as there is *no* "FCC" for the whole of Europe.
Britards. These people do not *deserve* your money. Why should they have it?
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