PB666

Zenit enlargement therapy?

Why short lived, xexon can be stored indefinitely (argon is a cheap replacement).

Asparagas? Life imitating fantasy. I actually like the design. Think I might create a rocket myself. The boosters partially tucked under the second stage, sears-haack +Mach shape on the bottom, shows some modern sophistication.

Maybe. A 90 lb robotic cube sat with a couple of solar panels and ION drive. http://www.busek.com/index_htm_files/70008514 RevD Busek Ion Thrusters.pdf on a metal cage with some solar panels. How about sticking a insulate probe in the satellite and discharging 100 kV. You could launch a 200 of these from an F9 and have them wandering LEO shadowing potential target ready to strike at a moments notice. 1/2 meter cubed, about the size of space junk. You could even give them a legit function of pushing bits of space junk into atmosphere intercepting orbits, with 8500 DV to play with they can pull themselves out many times. placing a probe along a tangential surface and giving that surface 50 dV of thrust (uncontrollable spin). Then have a sophisticated computer that pulse thrust sending the satellite into the atmosphere. Think of this something that clamps onto the satellite, then fills a large parachute shape plastic bag 100s of feet across with an aerogel increasing drag by 100 or 1000 fold and also drills a hole in the monopropellant tank.

BFS is the new ITS, similarly undefined thing.

Well if its a rocket you can launch it from Diego Garcia and you don't need BFR. You don't need to reach orbit. The US has bases in the Indian Ocean, in the Atlantic, at several points in the Pacific. There is no need for an 150 t payload to orbit. One other thing, how are you going to load 2 tanks into a rocket in an emergency. It would be cheaper to take a used 747 from the desert and put two tanks in it, and land the 747 in another desert and roll the tank out wasting the 747. This whole line of thought is silly and is about as off-topic as one can get while still mentioning something space X.

Talk about something that would be completely useless on Mars (Insufficient pressure, no oxygen) or Venus (no oxygen, too hot for a turbo prop to function).

I don't know if this is a known issue or unknown issue. Trying to set up a base on the permanent termination boundary of Mercury at its Northern pole. As a approach the pole the sun splits into two, one Sun that shines and the other that is an yellow disk. As I get closer to the north pole the shining sun never crosses the horizon (stays many degrees below the horizon) the unshining crosses the horizon for about 1/3rd of a year of Mercury but does not illuminate the solar panels or anything else. I understand that mercuries axial tilt is 1 to 5' (alot of uncertainty) so there should be places high on mercuries surface that always have sun.

One tank is going to make a difference where? 62,000,000$ launch to deliver one tank. "hey everyone a missile is coming, no wait it didn't explode" "What's in it" "An unmanned tank, looks like" [lest we forget tanks are not space proof, you will die if you are in that tank about 10,000 meters] "Tanks from [deity], [deity is great]" "Lets man it!"

Hah, soviet tanks run on Vodka, they hardly notice the landing. http://www.dailymail.co.uk/news/article-3552267/Not-Humvee-withstand-dropped-hundreds-feet-earth-Army-destroys-three-vehicles-parachutes-fail-training-mission.html And this is they way we do it in the US, 65t not a problem . . . . . . .

I think what the Airforce would really like is better eyes-in-the-sky ability. A satellite at 200,000 m just does not have the resolution that something 20,000 m. The problem is that the SR-71 was retired and just traveled too fast (Mach 3). I think if they had a choice today the battle ground is in SW asia, the need for speed is 100 times less, the desire is to hoover so high that turbulance and other aerodynamic forces are minimal (except upper end of jet stream). And to be able to mount every type of ground sensing equipment, which would include the ability to laser target (heat map) targets on the ground down to about 1 cm resolution. They really need something with a low ram type intake jet, low wing loading high lift and low fuel consumption. Primarily what are the targets. . . .N. Korea, mobile launch systems and underground assembly facilities. Iran . . .same. SW asia, moving targets that are not easily distinguished from non-moving targets. Our active targets are just about all incapable of targeting the high altitude surveillance due to a lack of appropriate radar systems and surface to air missiles. The point is that we know where the Russians are just about all the time, true to form they are a bear in the forest (big and scarey), but the game of they day are martins and ferrets, we need to be able to sense the undetectable. We had an SR-71 program, we could have made it into a Mach 5, 30,000 meter spyplane. Not only did we stop building them we stopped using them altogether. If the Airforce wants to get into space it knows how to, NASA after all was split from the Air Force. I don't see the airforce screaming that they need a 1000 more surveillance satellites in orbit, its the communication companies that are spamming satellites.

Why are you spamming these links, they have already been posted before? Oh I forgot one thing about power drills, all of them have a fan inline with the rotor to cool them down. Since the air in Mars is like 1/15th the density of our atmosphere, the cooling effect is alot less. To actually use power drills you need a device designed to work on Mars, not earth which means Earth-training with drills requires an improvised tool.

Power tools require batteries, batteries have a finite life in terms of recharging cycles. The alternative is to be dragging around extension cords. I frankly will use a power tool if its within a certain distance, but there is a reason, a properly designed tool allows one to apply maximum force (weight) to a screw while applying twisting force. This means there is a smaller chance of fouling the head of the screw but a bigger chance of breaking the head of the screw off (such as stainless steel screws). To solve the stainless steel screw problem after threading the hole for a screw I use a sacrifice screw to clean the threads out and then screw in with power drill and applying torque to the desired level. Lets face it, any colony on Mars will require supply drops, they are expensive as hell so putting really expensive batteries in the supplies is a no brainer, the battery would need to be 10,000$ per unit to justify a lower cost battery. Based on that you are going to send the most expensive battery/drill system that will do the job. What about the difference in time in putting on a real space suit, the added difficulty in breathing in a real space suit with lower pressure, the effort and time not to damage the suit in use (a pressurized suit is going to be more of a pin cushion relative to an unpressurized suit), the effort required to detox the suit back at the station, the effort of getting out of a real suit and staying mars dust free and the added effort of building a real mars shelther that is also free of real martian dust.

Lets examine what happened to this thread, we went from rubber-band assisted launch mechanisms to arguing over whether the ejection charge is a first stage or not. The problem is how to gain dV so as to reduce 1st stage size and increase 2nd stage. Its not an argument as to whether you would or would not blow up a nuclear power submarine if you did not use some sort of ejection charge as per the point no-one is going to launch a Mars targeting space craft from a 100 feet underwater. This is quite easy, buy some land in Ecuador, build a launch site there, take the rocket to the site and launch. If you don't like equador find an active volcanoe in the pacific Hawai'i (i.e. 19°34′N 155°30′W ) 9' closer to the equator relative to Cape canaveral. Note that I used to use Ecuador as a launch site, the problem though is equitorial is only a really good ideo for GTO targeting, its not such a great idea for targeting objects elsewhere in the solar system because theta required to plane match another celestial there is a time of day of launch resulting in a AtP burn to escape that matches the required theta . Elevation 4000 meters. Reduction of specific thermodynamic energy = 40,000 J/kg total thermodynamic energy required to make orbit ~ 1400000 j/Kg total kinetic energy required to sustain orbit = 122448558 Minimum dV gained by launching 4000 m higher = 1.2 m/s (pure) dV. dV gain as a result of ISP gain - engine based calculation dV gained as a result of lower drag below Mach 1 - form based calculation dV gained as a result of using a more efficient engine design - design based calculation. dV gained as a result of reaching Max Q (Super Mach) higher in the atmosphere - again form and structural based calculation dV gained as a result of having a higher TWR. dV gained as a result of having a larger second stage, at least 4 times the composite of all the other dV gains.

dV required to get to orbit. . . . . .18303.3 (v orbit at surface). Add another couple thousand for height related stuff . . . . .20,000 m/s it almost approach earths orbital speed about the sun. mu = 4E15 (notice my decimal places) And Koibels running around with 20k dV rockets . . . . lol. Giraff's would have shorter necks, rain would hurt, hail would be lethal,

If we were to apply the ratio 9.9 /5.5 = 1.8. 1.8 time 13.3 = 23.94 then the core of this 'Earth-like' planet is entirely heavy metal siderophiles.

That is not entirely due to iron. The core is rich in heavy siderophiles because of gravimetric sifting during the gravitational heat formation of the early earth. The assumption is that the early earths core was hotter (due to a higher abundance of radioactivity) and was more molten these sifted to the center and formed concentric spheres as the core cooled. Platinum - d = 21.45 Iridium (a common component formed from asteroid collisions) - d = 22.56 Osmium - d = 22.59 if d = 13.3 and density of iron compressed = 9 then relative volume of center is 2.25 Iron:1 siderophile

Superconductors need a huge amount of refrigeration and heat conductance for that refrigeration system. In space the sun will be striking the outside of the conductor it will transmit heat into the interior which will need to be cooled. The second issue is superconductors may not be structural, so you need to add structural weight on top of that. Third problem is that your refrigerant lines are on you ship, your power source is up to a km away, that refrigerant needs to be cycled over a 2 km stretch and you have 2 wires you have to do this. You are making a grand assumption that superconduction, low boiling point gases and cooling systems will be applicable without any aforementioned knowledge that they will work under these circumstances. Wrong, there is the skin effect. In any large gauge electrical wire running at high tension electrons tend to move at the surface of the wire. Increasing the cross-sectional area of a wire by 2 increases the maximum conductance of the wire by SQRT(2). Secondarily the surface is the coolest part of the wire, resistance increases with heat, and so larger wires have higher internal temperatures. This is the reason grosbeak and other similar wires have low conductance high thermal stability steel at their centers and that they break the conductor into many strands at the surface to reduce eddy formation in the wire. These wires are primarily aluminum structural but have steel assist, this is for periods of peak demand and peak stress. On a cold winters night where demand is very high but winds are blowing hard, the line gets hot it stretches and one line makes contact with the next, hard blow . . . . power is out for the next day. Here is the heat related resistance of aluminum. The temperature coefficient (a= alpha for electrical resistance is 3.9x10-3/degree C). R = R0 (1 + a * (T - T0) http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html Electrical connections need to be close to cells. You can only step of voltage on the panel itself so much before you get arcing between two opposing voltages. Therefore from the cell cluster to the main you need to step up voltage and then step up voltage again (and alternate) for transmission over the wire. The higher the frequency the more information that is carried in hv and less in the form of amperage. But the cooling fins are not structural and they add mass and create opportunity to ionize the gases of space resulting in losses. Secondarily for peak performance you need contact heat transfer between the wire to the fins and for reduced weight you need good emitters. The problem with good emitters is they are also good light (hv) absorbents so you need now to unidirectionally shield your wires from the sun. The whole point of this exercise is to bring together technologies that exist, not fantasies within some range of reasoning. If you are going to have to create a whole new variety of conductor just to move electricity then we are in the realm of vapor-ware. I don't mean this to impinge on creativity, but there is also the law of unintended consequences and you should be prepared to accept these until technologies designed to resolve these come about. Several problems you have been presented you have discounted in a hand waving manner, for example the critiques of structural stability. There have been experiments to see how things behave in space, the results have been rather unexpected. Piping, which I am very fond of, even without significant static load tends to become unstable without bracing with length and has a high tendency to want to bend and deform at the center. Things in space need to be cross-braced more frequently than you think. Carbon fiber is very nice, but its not aluminum piping and connectors that you can buy off the shelf (which I am very fond of in my spacecraft builds). Most carbon fiber applications are custom and such large solar collectors require either assembly in space or manufacturing the carbon-fiber in space. In the future these things may be widely available.

If its the core of a gas giant that has blown away then its not earth like. The latent heat of formation is much higher than that of earth, and the amount of radioisotopes in the core is much greater. Its unlikely that water would be stable on such a world for the two reasons stated. 1. If there is sufficient enough latent heat and ensolance to blow of the gas, then there is enough to blow off all the water. 2. If there is a tremedous amount of latent heat, given its pressure then there is enough to boil off all of the water via geothermal activity. (expect it to be a magnitude higher than earth) 3. Iron is the principle final product in current generation of stellar activity, it is the most stable product. The only way to get 9.93 is to have collected the dust from primarily supernova or from neutron star mergers. The earths density is a composite between the densities of Iron and Nickle (around d=8.0) of the cores and the oxygen (44% of the mantle) SiliconOxide (d=2.196) and Magnesium Oxide (d=3.6). In order for the planet to be double that of earths the oxides basically need to be gone, which means no water. In addition that oxide would need to be replaced with substantially more heavy metal. Final point, they reported density to 9.9 (two decimal places). This implies the result is accurate, therefore either it is accurate or their reporting method is wrong, in which case do not trust any of their data. Edit. This is what they reported 9.900 +0.880 to -1.340 (this is one S.D.) two S.D. (95.4% confidence interval) would be 7.22 to 11.66. Thus they might not have much radioactivity, but the planet would be largely, almost solely Iron and nickle with very little oxygen. Of course the density could be higher also, which means potentially very radioactive planet.

The dyson sphere will emit infrared no matter what, life has a temperature range, that temperature has a emmission range. The surface of the object has emmissivity of Q = EsT4 See other thread on solar electric power. The signature may be lower black body peak frequency compared to that around main sequence star but it would still be present.

When you insulate the wire you make matters worse, insulation traps heat, take a look at the heat stability characteristics for resistance in the conductors. Active cooling systems needs someplace to dump that heat and the longer the wire the less effective that cooling will be. I agree that aluminum wire is not choice, but liquid helium cooling in long wire, this wont work, helium boils at very low temperatures after which you have vapor lock in the lines, and whatever heat you generate has to be lost somewhere else. You really need to study the problem of heat dissipation more carefully. You are making assumptions about heat dissipation in space that with study you will find not to be true.

Really, traveling around in fake space suits is preparing people for mars, more or less fancy toys for over grown 5-year-olds.

You don't need mass driver per say, the circular velocity is around 2000 m/s (I forget exactly) but g = 1.66 m/s2. Consequently a rocket with TWR of 1 earth g need only rise 0.166 = sin theta. That requires a pitch of 9.5 cartesian degrees. All you need to do is place some teflon sliders and a pair of rails, start with pitch of zero and raise it to pitch 9.5 degrees as 'slide' of the rocket starts at zero thrust and pushes to full thrust. The space craft will hold the initial vertical velocity but its vertical velocity will increase and the pitch will need to decline. Just doing this you can eliminate almost all the waste of launching vertically (hoovering over the launch pad). Here are deduced acceleration for falcon F9 during launch. In the first figure TWR = (a apparent + 9.81)/9.81

So lets deal with the principle problem, and take the Falcon 9 as an example. Believe or not the falcon F9 does not take off at maximum g-force, in fact it lumbers off the launch pad with a TWR between 1.25 and 1.3. Why would they do this, doesn't it waste fuel. Technically its very dumb, for instance if you took off from the top of mount Everest you probably would want a TWR over 1.5 the problem with launching at Cape Canaveral is that its at sea level, so that about 80 seconds into the flight you hit MaxQ (the highest dynamic face pressure that the craft can safely withstand). So here is the issue, suppose the craft has a tolerance of 2x MaxQ on the face pressure beyond 1.5 structural distortion is already occurring. At certain velocities if you increase velocity you could damage the payload. There is no way to avoid Max Q, launching with a higher velocity only gets you there more quickly and at a lower altitude meaning more pressure, once you get past Max Q you have much more engine than you need because drag decreases and the fuel load decreases. So whats the point of having more engine, or starting thrust. Solutions to this problem- 1. Make the nose of the craft more aerodynamic (Sears Haack shape). More aerodynamic noses increase side drag beyond Mach 1. 2. Take off from a very high mountain, about the most you are going to get is a Andean mountain at 10,000 elevation. 3. Use boosters that then release from the rocket just before Max Q so that you only take the engine you need over. (These boosters would be small an unlikely recyclable). Unfortunately for your logic, the one who is retaliating doesn't know where your mobile launchers are and he is going after any stragglers. Second the Minute man missiles have a kill zone about 100 miles in diameter, they don't have to be close. Third you are in a country that started a doomsday war . . . your doomed, period. You might survive on the Krugerland Islands or someplace like that, not in Russia. I think that if I was the guy who launch an ICBM from the back of a 30 wheeler launcher I probably would no the location of the nearest cave and would steal russian jeep, put the remainder of my vodka in the gas tank, and head to that cave, picking up any cute Russian hitchhikers I might find on the way.