A SPACE SHUTTLE DESIGN
At $1000 to $10,000 a pound for transportation into space, there will never be any civilization in space.
Expecting a bit more launch business volume over the next 20 years, the space industry is proposing a variety of new systems to reduce the costs an amazing 30% in return for these savings being spent on the development of a second set of monster systems; shuttle replacements. No doubt cost overruns will use up any slack; that 30% is a salesman's-pitch number. So as we drift off into old age and death, the costs might just drop to $600 to $6000 a pound or more and there will still be no civilization in space.
At $0.50 a pound for ($3/gallon) and 24 lb (4 gal.) of fuel for 1 lb of payload, the minimum fuel costs are probably less than $12 a pound. Where does the other $980.00 a pound go? Into un-reusable hardware, into finance for ships that can be used once every 3 months instead of every other day, into delicate work to make things close to their failure limits and yet huge, into pork-filled solutions to get congressman's votes, into building to standards where the alternatives were kept off the decision table early on and, of course, some of it goes from tax payers into (disguised) sucking parasites.
Think of the situation as a pack of mean dogs clustered around and feeding on a heap of fallen tax payers. We will be attacked if we suggest that they ease up and otherwise, they will ignore us. It is not possible to reason with them directly; our values are too different. We must work around them and destroy their assumption with respect to the tax payers. Their assumption is that a solution costing less can't and will not be found. They can be expected to deny any proof of `found' short of demonstration before the press. Their main proof is that their (competent, in-house) research arm has not been able to find one.
A satellite massing around 500 Kg (or more) and costing under $20/lb would show the assumption to be wrong and facilitate running the parasites off thus freeing the tax-payers they feed on. It must be done in secret or at very low profile so that they can't use their excess power to forbid the research, enjoin flight testing for (bogus) public safety reasons, deny funding as best they can, sabotage equipment or co-opt key personnel. I envision a 500 Kg satellite, mostly maneuver fuel, that moved around the Soviet/USA space station and heckled it along with providing TV feed of the event. A very large zoom lens would help with staying at a useful and safe distance. So would a towed banner proclaiming/advertising the identity of the interloper.
If not us, Who? If not now, When? We will design an alternative to persuasive detail and champion it to possible clients that can add further detail to the design and build the parts for prototypes. More on the audience and clients later.
Tucson Space Society's Role
At this time, all I ask is that each member read over the plan and add detail as best they can, criticize what is there as best they can and to append their thoughts and problems as best they can. We will circulate the file among ourselves trying to reach equilibrium and THEN seek out more specialized and professional advice and help. If we show that we care enough to invest work, the people that can help us will be more inclined to invest with us. More on the advice and help below.
Summary of the Ferry System
1) It is based on the Air Force Dark Horse concept presented at the 1995 Phoenix Space Access Society Meeting in Phoenix. This is a rocket plane to go around the world once, along the way releasing a 1000 lb object of military interest, re-entering and landing where it came from, probably New Mexico. It runs on 99.9% hydrogen Peroxide (H2O2) and jet fuel (C4H10) consumed in 5 main and 2 minor motors and it is mainly fuel from a standard KC-10 tanker in the air. Dark Horse is a zero level sketch of an earth-space ferry vehicle/system.
2) Dark Horse has both landing gear and a pilot (U2 austere for a sub 20-hr. trip). Since it takes off and lands light, the landing gear is light. Rating both at a nominal 1000 lb each, leave them off. Now the same ship can LEO a 3,000 lb object. We loose a flexibility that the Air Force needs but we do not. Two more thousand pounds can be scored as payload for a total of about 2.5 tons. In space, at a civilization space station, the 2.5 ton payloads are unpacked and rejoined into larger objects of interest to civilization. For example, assembling space ships for trips to the moon.
3) This ferry has no landing gear. It is so light that it can land on water just as it stalls out, like a speed boat. Perhaps landing in the Salton Sea in California. With no fuel, no pilot, no life support, no cargo, no landing gear and no main jet fuel tank, it has as little density as possible; it is a bubble. The landing can be made less harsh by soap-foaming the water where it is reasonably expected to land.
4) If the ferry has no landing gear, then it has no take-off gear. It takes off from the back of a truck (a big truck) pushed by a couple of surplus jet engines (from old airliners) to 200 to 250 mph on a standard hard runway. It takes off as heavily laden with fuel as possible given these limits. It might contain 5 tons of jet fuel and 15 more tons of peroxide along with the proper cargo. The Runway Truck then returns for the next ferry. Big trucks are reliable and easily imagined to be able to make a 15 min. trip every hour and a half. The space port might have 3 such trucks all taking turns. We can remote control/automate the truck. Trucks working open pit mines run up to 300 tons of payload rock. Their parts may easily be adapted to a faster, briefer job with just 100 - 150 tons of payload moved on a wide, flat, hard road.
5) Old Air Force tankers this year's sale of 10 surplus tanker planes to Turkey) rehabilitated to the R standard cost about 10 million each. I want 20-30 of these tankers. The Dark Horse assumed a KC-10. Perhaps they can be made from Russian Antonov transports. Recent press articles suggest that such a plane can carry 200 tons of peroxide in 20 more tons of of tank. My ferry will want all they can carry and will hope for a delivery rate of about 4000 gal/min (under 15 min). This may require some new pumps on the tanker. The ferry is then very heavy and will have to use a great lot of thrust and attack angle to stay on station. The sooner the feed is over, the better. Perhaps the tanker could tow the ferry while it is being filled.
6) Like Black Horse, the ferry takes off with its jet fuel tank filled and does not top it off at the plane. The reaction is taken as
The ratio is 116 Kg jet fuel to 884 Kg Peroxide = 1000 Kg exhaust.
7) Once in orbit, the fairing around the cargo/nose is removed to recover (1) the cargo, (2), a 9-ft diameter circular section 10-ft long between the tank part of the plane and the fairing nose, 3) a 33 ft long by 4 ft wide tank for kerosene that forms part of the keel of the plane. The nose fairing is then re-attached to the ferry body for the return trip. My suggested attachment technology is via 1/4 inch bolts about 3/4 inches long with washers, said bolts being located every 3 inches inside. An electric wrench would properly torque each one. About half the payload fairing is now delivered cargo. There are alternatives based on steel spring clamps and screw threads. I like bolts because there is no symmetry problem like with screw threads and there remains access for welding the seam closed later, an alternative made difficult if the seam is inside a steel clamp. I expect sets of bolts moved around through robot tools like belts of machine-gun ammunition. Wire connections among them would remain after installation so that small parts do not go floating off. With a bolt very 3 degrees, the possibility of rotating the sections almost arbitrarily is strongly facilitated. Finally, the joint is open able, facilitating the salvage of the tube sections from one architecture to another. The two parts are reckoned at 1000-lb each. Once in orbit, the two parts are removed from the ship account and placed on the payload account. Leaving them in orbit helps the returning ship to be of low density. Low density means thin thermal protection as there is little cross sectional density to slow down.
8) The 10-ft long by 9-ft wide sections can be bolted together to form a longer tube. By adding special cases where the tube is made from two shorter tubes, each ending at non-90 degree angles, 90 degree, 45 degree, etc., corners can be turned to facilitate the construction of rings (approximate rings) from the tube sections. The cross sectional area is about the same as the inside of a box car. New railroad cars cost about $1000 /linear ft.
9) The 10-ft long by 9-ft wide sections have one port on one side. The port is (you guessed it) 4-ft wide and accommodates the 4-ft wide tubes as a bolted (plumbing-like) connection. For ferry work, the port contains or supports the fittings and stuff for accepting the refueling drogue. That part is no longer necessary and its scrap value (say in extrudable or die-castable aluminum) exceeds its surface value ($2.00/lb) so it is not returned. It, too, is now payload.
10) I envision 6 large and 2 small motors, with perhaps some vectoring possibility. These should be easily removable and made of proper forged titanium, grafitic iron or whatever. A hydrogen peroxide motor passes the peroxide over a silver catalyst (down a silver-plated pipe or through a silver mesh) and it then heats itself up good and hot and then the heat itself facilitates the decomposition reaction. The resulting steam contains a useful amount of free oxygen so mix it with jet fuel and it heats up even more. Then suck some of the heat back from the exhaust (radiation from exhaust stream) and inject the heat back into the motor as hot fuel. Black Horse envisions some 1740 psi chamber pressure. A ship at 174,000 lb behind the tanker then needs 100 sq in. With 6 motors, that comes to 17 sq in each motor. As a circle, the radius is thus:
d = (2 x r) = 2(sqrt(17/3.14)) = sqrt (18) = 4.5 inches
inches of motor throat diameter for each of the 6 main engines. I wonder if extending the throat from a point to about a foot long would facilitate sucking heat from the exhaust into the cold jet fuel? Remember the ship that ejected 50,000 psi cold hydrogen?
11) The main tank at 9 ft diameter (like the removable fairing) is too big except that it contains the jet fuel inside its apparent volume. Relate to coaxial cylinders. Coaxial and cylinder are inefficient packaging but there is mitigation. There is no strong reason to make the ferry totally circular like an Atlas or Flash Gordins ship. Flatten the 9 ft to make wing and re-entry cross section until it is as flat as the motor section allows. Make a lifting body within the constrains. Remember that it flies up point first like an arrow and returns sideways like a parachute. This wing will be thickish. It has to function between 250 mph and 550 mph while it is tanking up and then help some to offset levitation expense as it goes from Mach 1 to Mach 6 or so. Beyond that, keep the G force up and go for orbit. Much compromise is necessary here.
12) If a 9-ft diameter circular section is made square by cording off the walls with panels full of closets, stuff, gear, plumbing, wiring and the like, the core space is still about 6 ft on a side. There is going to be 10 more axial ft. of 9 ft diameter interior space for every ferry trip making interior space and more interior space so skip most of the cost of compressing and miniaturizing parts, of super-reliability, of dense packing and the like and go with distributed functions made of easily replaced, reliable and maintainable standard modules. One of the square panels in each 10 ft long section will involve/cover the side-access panel/part. These are like nock-out plugs on electrical boxes. Open when needed. They might be easily converted to windows via a standard adapter. They might also be easily converted to turrets or interface with robot arms. There will be one to deal with every 10 feet. They might point at any angle with respect to the previous one or next one according to the spacing of the bolts along the seams. Someone will have to think ahead.
13) The jet fuel tanks, once cleaned up, have dome-ends that (you guessed it,) unbolt. More of these ends may accumulate than can be used. It would help if they were made of a material with good salvage value. For example, if they can be brushed off, chopped up and fed almost directly into an aluminum extruder. The tanks can have (multiple) (angled) bolt seams in the middle as well. The tank weight added by the extra seams and non-spherical shape is scored as payload. There is a new complex zinc-based solder for aluminum that does not destroy the aluminum's heat treatment or work hardening. The historical absence of such a solder is the main reason that large jet aircraft are riveted together. Run strings of the 9-ft diameter tube segments in parallel and connect them with the 4-ft diameter tank segments. Place (air lock) security doors in the 4-ft tubes such that they are normally closed. The ferry's cargo fairing could contain a 6 or 8 sided node for connecting the 4-ft tubes together. If it weights less than 3000 lb, no problem. A node for 9 ft tubes could be welded together from a bolted together assembly made of 4 or 8 similar pieces per side. The 8-piece design might be made of pieces forged or die cast at the station. Imagine bolting it together so that the total alignment might be secure and then welding all the seams firmly closed. In the present design large spaces are expensive and somewhat cramped ones are cheap.
14) Anyone that can demonstrate less than $20/lb for transportation can demand \$2 billion of NASA's 13 billions of regular money forever; Take from the failures and give to the successful. Assume this is so; that the program spends \$2 billion a year. The situation is recursive and demands this level of funding to achieve the sub $20/lb. target figure. Scale reduces costs. With this funding a fleet of 100 of these ferries and enough tankers to run each of them every other day or so becomes possible. That entails one launch every half hour about 300 days a year. The tanker fleet flies more than once a day each plane (rough average), but not more often than a short-haul passenger airliner. A nuclear power plant (can still be purchased from the French) to make pipeline peroxide to keep long-term costs down. Peroxide is non-polluting. The space port might consume 5 million pounds of it a day. The jet fuel might be made from pressure-reacted organic trash mush (pipelined from LA if the space port is located along the Salton Sea) that would otherwise go to land-fills. Good PR.
15) As reliability improves, six men can be the payload in a special man-can The workers do the part movement, bolt work and station assembly. A first LEO station might be made of tubes and run at zero-G to form a loading dock to deal with incoming ferries and push off returning ones to wait for their return window. Perhaps 19 tubes each 500 feet long and 9-ft diameter, all cross linked by many 33 ft long 4 ft wide jet fuel tank tubes, forming a hexagonal core large enough to rotate a fresh (unshortened) ferry. Fill the gaps between the tubes (make walls) with wire-reinforced fabric to catch dropped stuff and whatever. Add robot arms that will do most of the bolt work. Workers do regular work from arms sticking out of cans that ride on the ends of mechanical arms such as are currently used by tree trimmers and painters at U of A. The work can would have a back hatch similar to the one on a Russian space suit. Special case work demanding a regular space suit is excepted but not all expected work requires such a suit.
16) The mission of our early space station is not the collection of scientific data (according to some religion that demands faith in its eventual value). Contracts to collect data for independent external parties might be solicited and executed. The workers and staff make/assemble other space stations, space ships, rotating 1/5 G habitation rings, living quarters, satellite repairs, refueling, etc.. A ship that is not going to be flying up again is not sent back; it is metabolized for its nose fairing, materials, motors, etc.. Some individual parts might be sent back on subsequent returning ferry.
17) In 10 years, there will be the equivalent of 50 space stations massing an average of 3,000,000 kilos each (3000 tons). This assumes that half the lifted mass is consumed like fuel, wine, pizza, workers, etc.. Of this 50, probably 5 stations might be for civilization if I can find buyers for the 45 other ones.
If the US Navy had 45 warships in space, all looking down on the oceans, they would need almost no surface ships at all. A one ton basalt rock, coming down under guidance at Mach 10 could hit a ship deck and break the ship's keel. Dead, bent and perhaps sinking....A moment later, the station is gone but with 49 other ships up there, the target is soon in range of the next one. They spent $900 million on battle ships since Viet Nam.... Ask the Navy for $5 billion for each of the next 10 years for a fleet of extra-atmospheric frigates. They could fire their grit guns down on American cities for the 4-th of July evening fireworks show.
18) A 22 caliber rifle can get about 1000 fps from 1 ft of barrel. A rail gun should be able to get 1000 fps for the same bullet for each foot of barrel. A 500 ft barrel would get 100 miles a second. At that velocity, a plasma beam goes through any material target leaving the intersected matter with more energy than it would have had if it been made of detonating TNT. Parallel to the rifle tube one can imagine a pair of 500-ft long, 4-ft diameter laser tubes (infra red, microwave). These can be used as frequently as cooling considerations allow. Hang some solar panels on it, big ones and it starts to look like an old fashioned sailing ship.
19) The US Air Force needs to shoot down boost-stage ICBM's so why not shoot from high ground? A few extra-atmospheric interceptors (running on peroxide and C4H10) to cover the in-between spaces and 45 more 3000 ton mother ships. That would be some 7 Boing 777 jets worth of mass/space each mother. No airliner, rocket, parked plane, hanger, fuel truck, ..... would be secure for more than a half hour. Sustained, multi ship attack with microwaves would eventually heat bunker steel to un-inhabitable temperatures. Special, 1-ton Mach 50 penetrators could dig Saddam out of his 40-ft deep bunker. The Air Force could afford $5 billion a year for each of the next 10 years. Why should the Navy get all the space ships, 4-th of July PR and fun space billets? This is a small fraction of the military's 270 billion year share of the tax pie.
20) Consider the China Lake facility: 6000 engineers and stuff continuously redesigning sidewinder missiles. Now that the cold war is over, our ferry is not much different. They could easily build a truck, ferry model, small tanker and then toss the thing up, refuel it, zoom it into the sky, coast it back and splash-land it. This, I expect, with hobby effort. Is it a lot to ask of 10 fellows with their own, self-made largish model planes? This, I expect, without permission or grant or breach of security to those whose public pork is threatened by great efficiency. The second round, to make it larger, faster, streamlined, specifically lighter and with the proper joinery, might not cost much at all. The British have a motor design from their one satellite launch about 30 years ago. Once this worked well enough, a real tanker, a larger unit, perhaps without exotic/optimal tanks, could refuel from a tanker and try for orbit and dramatic PR. If it could fly up to the US/USSR station and take its video document while towing a (inflation-stiffened) 100 pound banner saying China Lake Rules..... As they are interviewed by the press, they claim victory over a NASA scam to keep prices up there and demand the prize, \$3 billion of NASA budget lines moved over to them to run a productive program for a minimum of 10 years. The military is easily coopted as a client for a zillion tons of space ships. The program easily expands to 10 billion a year. A space ship is a space station with a motor (a small one probably). >From this vast mess, crumbs fall to us, crumbs enough to be, on close examination, the seeds of civilization in space and a lot of evntually-to-be surplus mass to feed it on.
21) Three or four countries could afford space fleets if they gouged their current military budgets hard enough to free up $10 bill a year. Sport-like competition could get some impressive monstrosities up there before we are too old to watch TV. Ten percent of a great lot is a lot. If we can make their part large enough, and lobby for a 10 percent civilization fraction, then the civilization fraction becomes a lot in absolute terms though perhaps not in relative terms.
Musings, Details and Problems
There are several limits that constrain the solution. One is that the tanker capacity can't be exceeded without paying way over $75 million per tanker. Someone must pay for the design of the new tanker and not just the marginal cost of one more unit or the surplus cost of an available one. The second is that the 10-ft long fairing segment must be of maximum circular diameter. This entails that the jet fuel container be inside it. Third, Jet fuel and hydrogen peroxide are not cryogenic and the reaction products do not summarily destroy the motor so trying another fuel is probably futile regardless of the promised increase in specific impulse. Instead, increase vehicle reliability and decrease fuel costs and then shoot it more often.
Much of this is a building code for parts compatibility. Special needs may be accommodated by specific exceptional changes. Since the ferry's are cheap and might be risked as they near the ends of their expected service lives, absurd verification of change implications might be avoided by paying insurance on experiments. For example, the 4 ft tube segment might be extended by 10 feet into the cargo space if jet fuel is to be a large part of the current cargo. A little computer modeling followed by building it and trying it.
A successful program might suggest technical evolution. This might include a Mach-4 tanker toting a cargo of 150,000 lb of hydrogen peroxide to an altitude of 100,000 feet. As long as wings can be passively cooled and the wings work, the tanker stage can work. With this component, a larger ferry might be designed, one with a larger diameter (12 ft?) fairing segment.
Add the volumes of the two fuel components together to get the volume of the 9-ft diameter fuel tank. Solve for its length. Given that length, solve for the diameter of the jet fuel tank of the same length. Instead of putting both on the same axis, sink the jet fuel tank to the side/bottom/keel of the peroxide tank. Slide it in on a modest rail interlock. Let peroxide contact the exterior of the jet fuel tank.
From the 9-ft fairing section intersection with the ferry proper working back flatten the peroxide tank from 9-ft high to 4 ft high to make a wing that probably curves up to form, on the curved side, the belly of the lifting body for anti-lifting (re-entry). Add a few feet on the back where the wing is getting thin for motors (about 15 inches high at the bell, with bells about 5-ft apart, with the wing working down to 0.1 inch thinness between the motors. In the spaces between the motors, put 5 tanks for more peroxide for re-entry and the like. These tanks would be about 4 ft high at one end, zero at the other, and 5 feet wide. The result is a wing that gets thin without the 4-ft tank making excess demands on anything. Remember that this tank stays behind when the fairing segment is left in space.
It may well be that more empty tube is accumulated than can be used. The tubes might be made of different materials in anticipation of different salvage fates. What can we expect it to weigh per foot of length? As much as a Lear Jet per foot, unloaded and dry? If the fairing section is not appended to the launch vehicle on the truck, and no cargo is added, then the payload is the fuel not used when it arrives. At the very least, the mass of the fairing is substituted for mass of fuel at some ratio. What is the ratio?
Along the same line, if there is to be no other cargo, the fairing segment to be left in orbit might be elongated proportionately. The truck, refueling and assembly operations should have no problems.
The man-can expects a 2-3 hour trip and the module might expect to take them back. Alternatively, two might fit inside the nose fairing and they can come back in pairs, allowing the man can to be converted into a apartment module.
If one of the 6 motors craps out, I expect the other 5 to do the work even if they use up the fuel reserve for de-orbiting. Refueling is some of what the space station is for. The control system should be able to deal with this and adjust individual motor thrusts to keep the total from being asymmetrical. I expect the barge to pick it from the water very gently. It is one thing to flumep down on the water like a bouncing speed boat and quite another to take a hull ding from a bird. Thus, I expect it to be barged to a ramp and pulled from the water like a boat on a trailer. If it contains space men, they should be removed when the barge meets the ferry. Perhaps a small door (12x16 in.) in the nose fairing on some model fairing, directed down toward the water so that the crew (3-6 space folk) can squirm out and drop 2 feet into the water.
Ninety ships each the size of 7 Bowing 777 hulls, could each have a crew of 30. 2700 space men up for half-year tours? That would come to 5400 troopers per year. For 10% more for civilians that comes to 6000 person trips a year not including hotel guests. That then comes to 1000 man shots in man cans or 3 man cans a day out of 50 shots a day from the space port. Scheduled at 8 hour intervals or once every 3 days to different LEO stations. Inside this is the untested assumption that there is no window problem. This remains to be examined.
The ferry hulls will ware out, as will the motors. Every day, we will need 6 flat cars loaded with fairing sections, 12 cars with new jet fuel tanks. Every few days the port will need a new ferry hull. We need endless millions of lb of rocket fuel and a great volume of jet fuel. All thus suggests a fair set of small industrial businesses that supply the port. A hotel for the space-bourn, food packages for those up there, making new robot arms, new connection nodes, new tank splices, new rocket motors, new tanks, etc. Perhaps visions of these businesses could be used to interface with the dreams of the personnel at China Lake to jump the government ship and become free men making space ships at the space port.