PB666

What I find amazing here is that we are repeatedly talking about Inefficient power systems working at a scale in space that no space agency has even come close to attempting. More amazing is that we hand wave the heat problem away like heat is easy enough to toss off the ship as fairy dust. Lets have some equations here, you have 66MW of heat generation. The power drop of 8'K off the first heat exchanger. . . . . . . . .make these things credible show the math. What is the size of the heat exchanger, how is the 13.5 MW of power generated (no steam obviously) . . . . . . Where are the equations for determining the size of the heat panels???? The claim in the OP is that this device can generate power from ambient heat in (whatever), this means the temperature drops and it sends current. (Sounds awfully like perpetual motion because it can establish a temperature gradient where none exists). But lets say it can do this with a very tiny gradient.

I should add, 13.5 MW is nothing with regard to ION driven power in space. Its all greek to me.

But if the properly compacted graphene generator works your power efficiency would be much higher. Note a power efficiency of 21.6 percent.

Because a colony on Mercury makes more sense than Venus. For one the average surface temperature of Mercury is 100'C lower than that of Venus. Surface temperature in some regions much lower. Surface pressure better No Sulfur dioxides and trioxides in the atmosphere. Water on surface of permanently colder areas of Mercury. All the power you want is just a solar panel, transformer and HV extension cord away. We know how to get to Mercury and land, its just a big version and big dV of the moon. We have no idea how to land on Venus and to do so would be insane. We know how to land on Mars but there is no power source on Mars that allows us to do the things we need to do to survive. Earth is not Venus. Ground temperature is influenced by transpiration and evaporation and is keep moderate by grasses and trees.

But it cost energy to move heat up a heat gradient instead of away from it. Heat objects tend to radiate. This is to say in a typical powerplant design the steam in the reactor has the highest energy density, once it transfer via heat exchanger to the turbine water the steam temperature and pressure fall some, then over the turbine it looses more energy density per mole of water. The water that cools this has a lower heat density. This is typical so if you have a design that creates a different direction (for example your fusion is being conducted in you radiator) then you need to give details and not wave hands.

So i have been tinkering with the numbers. I was going to model the problem but unfortunately I could not get emissives to work in Unity 5 due to the increased number of steps now needed to do so (and the fact the versions of Unity 5 im using appears to be glitched). I was a matter of luck that this happened. What I have determined is that for kicking using low acceleration is that the time required in days is 260 days /(acceleration * theta) where theta (degrees) is the time aloted per orbit (degrees converted to time) for burning ones engines. For example if A = 0.01 and theta is 10' (5 degrees before Pe to 5 degrees after) then its 2600 days to reach a point where the engines can be continously fired. If we fired over period of 100' that time would be cut to 260 days but the cost in fuel would increase due to spiralling away from the planet. The typical burn starts at 15dV/degree*a Because we need about 3000 dV the 1 to 1.5 dV per burn (burn dV decreases because orbital speed increases at Pe). it translates to >2698 orbits, during the last burn the engines are fire about 50 seconds before Pe and fire continuously until transfer-planet intercepting orbit is achieved. Here is the setup. 200 MegaWatt nuclear reactor 50t (can be turn on and off when needed) 3040 square meter of HiPEP at 26 kg per meter 80t Payload 200t Fuel 38.4 t Fuel tank 3.84 t This fuel is 10% more then the fuel need to get to Mars and return assuming that 200t of payload is delivered in LMO and 20t is returned to LEO. Total weight leaving earth is 372,295 kg total returned to Earth 153,895 kg. even if the power of the FNR increases 2 fold you do not get the full benefit because the HiPEP weight would increase by 80t. The critical issue is power output on the ION thrusters, that needs to go up by a factor of 2 or more. Whereas with electro solar the ION thruster mass it trivial compared to the weight of the solar panels becuase of the presumptive power density of Fusion electric the reactor weight becomes less of a concern relative to the thruster weight. Starting orbit was alt = 140,000. Here are the value for different starting orbits. Altitude 200000 255.6 days/(acceleration * theta). 400000 244.8 days/(acceleration * theta) 800000 234.4 days/(acceleration * theta) 1,600,000 206.9 days/(acceleration * theta) 1.5 Earth radius (3185000 alt) 170.6 days/(acceleration * theta) 2 Earth radius 186.6 days/(acceleration * theta) GTO 46.6 days/ " " Some other things are learned by this excercise. Approach Jovian inner satellites is not recommended with ION drive systems, Although it could deliver a rocket that might do so, the time requirements to correct orbit near a large gas giant would be prohibitive. GTO 47.7 days/" " And it makes really no sense to bring a bus down to LEO if the majority of its weight is not-expendable when loads can be delivered rapidly to GTO despite the loss of dV associated with LfOX based systems versus ION drives. THe drag alone created by AoA crossectional area of 3040 m2 suffices as a good enough reason not to go below 200,000 meters. Anyway ION drive bases 39 or 89 days to MARS will not work, the output density to weight ratios to the drives are two low. These slow accelerating space tugs need to stay away from the depths of gravity wells. It may be possible to create a fusion ION drive that has alot higher thrust and power output that circumvents the problem.

Another handwaving argument to ignore. It would be hotter underground than cooler. Heat increases with pressure for example if you dig 2 miles under the permafrost the earth is uncomfortably hot. At the center of Venus there is residual heat from gravitational energy provided during accretion as well as heat from radioisotopic decay. Thus the gradient begins at ground level and increases to the core.

I think you fission reactor just melted everywhere. Convection and evaporation transfer heat much, much more efficiently than simple radiation, that is the problem.

Fission Power systems on Earth are almost entirely steamed based, its a big problem. They are Nuclear Thermal, heat is used to make steam, steam creates work as the differential of gas and liquid. The problem is that for steam generation the catalyst are the cooling towers and water retention areas. Without these there is no way to develope a differential and what you create is a steam critical instead of prompt critcal bomb. ION drives have ISPs that exceed 10,000 if that is what you want. ION drives have 1-efficiency based waste heat generation that ultimately limits output per unit area. We are talking about 100kW per meter which means there is 20kW per meter of waste heat, is no better for VASIMR, in fact its probably worse. For classical ION Drive the thrusters are spread out over a plane where they can radiate from their back sides. Having said that no-one has really studied the waste heat disposal process. With such a device you could use liquid sodium to transfer waste heat from the ION drives and to a coil where the heat is transfered to the graphene and then used to make additional power. Neutrons are useful in converting the hydrogen into deuterium.

Yes but you need an alternator, and the alternator needs to work at 462'C. Silly. There is nothing on the venusian surface that we don't already have on earth, except an survivable temperature and pressure.

So what kind of battery can operate at 462'C to run this computer? And of course you need a transmitter. A camera with a digital photocell, some ground testing equipment, possibly a laser. . . . . . .

https://www.unige.ch/communication/communiques/en/2017/cdp211117/

The problem. Solar electric system need lots of power, however either one has hugely bulk solar electric systems or highly inefficient and heavy fission systems; fusions based power sources are vapor-ware. http://www.sciencealert.com/graphene-levy-flights-limitless-power-future-electronic-devices Fission reactors are relatively efficient on land, but require constant servicing because steam generation is rather repair intensive proposition. Replacing steam generation with thermocouples results in a virtually care free system that generates many times more heat than power. The above link has an alternative, single layer graphene sheets that can extract heat from ambient air to create current. Whichever system one chooses, this can be used to cool them down and create power. Its not a perpetual motion machine as it might seem, the heat still has to dissipate somewhere (such as in an ION drive or transformer). It might also be a way to cool ION drives allowing them to work at higher rated powers. (And thus less weight and less crosssectional area for thrusters) (-) --------- Ossilator (~)------- Step Up transformer ---------- 10-100KV ------------------->|------------ ION Drive

"The pie is finite," says Bob Grimm, a geophysicist at the Southwest Research Institute in Boulder, Colorado, and chairman of NASA's Venus Exploration Analysis Group. "If we want to improve Venus's share, we have to have some kind of initial mission to get people excited again." -http://www.sciencemag.org/news/2017/11/armed-tough-computer-chips-scientists-are-ready-return-hell-venus Well, if you want exciting try blasted out of a capsule with a pressure 92 times earth surface and a temperature 462'C (hot spots go up to 827'C). You will be ablaze with excitement!!!!! Any volunteers?

http://start.att.net/player/category/news/article/geobeats-asteroid_nasa_once_called_potentially_hazardous_wi-5min

Seriously.

HYdrogen is not a normal cryogenic fluid, it leaks from valves, seams in welded metal, just about everything. In space nothing has a temperature until it collides with something else. Therefore 25K solar gas at collision with hydrogen produces the temperature. The solar wind also does not have a temperature until it collides it basically moving in a laminar fashion away from the sun. The collisions of gas will emit down to 39 nm emitting in the far UV/X-ray. This covers the entire range of mid and near infrared.

The unaddressed 8000 lb elephant is how you kept the liquid hydrogen stable up until the point you went into stealth mode without producing a heat signature. Aside from that the ejected hydrogen can be detected because of collisions between solar wind and the gas, the collisions are extremely energetic and would emit over hydrogen's entire spectrum.

liquid hydrogen is extremely difficult to store in long space flights, it needs to be collected from around the storage container, condensed to high pressure, actively cooled and then returned as a liquid back to the tank. This requires energy input and produces energy output in the form of radiation. IN addition the glancing of solar wind produce a 10K temperature on the prograde edge that the vanblack would absorb and emit. While there is very very little matter in space, the matter that is there is extremely energetic (kinetic) and temperature is directly related to the energy gained from collisions. An object that is not absorbing solar and discharging hydrogen would have a noticably cold and hot side, this would clearly identify it as a manmade object. In addition the liquid hydrogen recycler would have a radiator surface that identified it on a cold background, also manmade. The assumption here is that the target race has a great IR telescope (like J Webb) and could pin point the difference between hot and cold. In addition since SC is intersystemic it would be identified as a local abnormality. Rather than making it less likely man-made, the effforts to hide its radiative heat signature would make it more obvious.

The planet is already degrading just as Mercury has been degraded and is still degrading due to outgassing of remnant rocky minerals on its surface. The difference is that a planet close to its star is degrading millions of times faster. Eventually the crust and mantle will melt and the core will merge with these two, as the surface decelerates the heavy metals at the center of the core will move prograde and the surface will move retrograde, a strong magnetic dipole will appear. The movement backwards will be accompanied by the sloughing of material off of its tail; however the rapid evolution of gas from the moving surfaces will create a boundary layer that slows orbital decay.

If you saw and asteroid bleeding off hydrogen gas with hydrogen emission spectrum are you going to think 'pitch black comet' or managed stealth system. Also, to cool that hydrogen to its triple point you need heat radiators. Because of entropy, it takes more energy to hide energy than the energy profile one is attempting to hide. IOW, not as stealthy as desired. In coming asteroid travel at up to 30,000 meters per second (even an earth bound escape velocity roid is traveling 11,500 meters per second when it hits the atmosphere. There earth is 6,500,000 meters in radius. if the average approach speed is 5000 meters per second then one earth radius is 1200 seconds. (20 minutes) . This means a fusiform shaped object could avoid detection by have a low profile to the earth to about 2 to 3 hours from earth. A reflective surface would not be detected until it almost reached earth. And if the object entered at the angle of the sun (meaning the suns rays hit from its back side) its reflected light would be difficult to detect at all. Even if an asteroid is detected with say an hour of impact, predicting were it would land if it had an oblique entry vector would not be easy. So now you are down to the last 15 minutes of flight where a large streak covers the afternoon sky. If this was done in an isolated place with few cell phones or other media. . . . . .it may get noticed but not recognized until days later. As to the disintegrating asteroid situation. Asteriods are filled with reductants and volatile materials. When they enter the atmosphere the pressure of oxygen at the leading edge increases many fold (Super mach behavior). The nature of super mach is that a pressure density builds up on the object, the boundary layer moves off the object. As we know from Rudolf Diesel's experiment if you compress air 20 times on a reductant it explodes. A asteroid that begins to break up in the lower atmosphere will also explode and the inhabitants in whatever ship inside risk catastrophic damage. This situation can be avoided by separating the lander from the chaff before reaching 100,000 meters.

There is less nitrogen and oxygen locked in Mercurial rock than on Mars and the outer planets. The albedo of Mercury and its proximity to the sun has forced the conversion of metal oxides into metals and oxygen free radicals that boil off and leave the atmosphere. The water you see on mercury's dark crater is the reaction of these oxides with the suns proton plasma (in solar flares) as the hydrogen streams around the light termination of the planet. Don't expect to find much oxygen until you did 100s of meters deep. It is not possible to terraform mercury . . . .life is not Spore, there is no god-mode terraforming tool. " Mercury is much smaller and its inner regions are not as compressed. Therefore, for it to have such a high density, its core must be large and rich in iron." wikipedia. Earths mantle-crust is thicker because it is loaded with oxides, sulfates and carbonates. "Mercury's surface composition is very different from that of other planets in the solar system. It is dominated by minerals high in magnesium and enriched in sulfur. This composition is similar to that expected from partial melts of enstatite chondrites, a rare type of meteorite that formed at high temperatures in highly reducing (low oxygen) conditions in the inner solar system." -https://phys.org/news/2012-09-characterizing-surface-composition-mercury.html#jCp MgCO3 --(heat)---> MgO + CO2(gas) ----(heat)---> Mg + O*(reactive free radical) You might, if you are very lucky, find calcium oxide on the surface. MgSO4 -(heat)--->MgS + 4O* Free magnesium is great for you ION drives, but its going to strip oxygen and carbonate off of anything that bears them in mercury's soil.

Yeah but in reality his numbers are all based on a set of what ifs all of which pretty much don't exist. He has no power supply, the only power supply that could do it is fusion. The problem is that its NOT just the weight of the reactor, its also the weight of the cooling radiators (steam generation will not work without heat transfer . . .it is just a bomb without heat transfer). I was very generous in the ION drives, very; the reality is they would likely occupy 10 times the area and the infrastructure required would be prohibitive. The trip is if I had a power supply that could generate 50 MW and not weigh >1/3rd the weight of the total ship then I could get to Mars. The smallest operational 'maybe someday a fusion reactor' is 5.5 meters across about 2 meters high and made up of aluminum and magnets made of rare earth minerals. >100 t of weight probably 150 to 200t. This does not include the steam generator components in the reactor, the turbine, the radiators . . . . . . . . . The reason I showed the fusion reactor is to basically argue, look fusion is great if you need lots of power, but its not physics-less power, these things have alot of mass and supporting infrastructure, and its not clear that long-term steam-power is a viable thing in space. Lots of mass and supporting structure mean . . .very hard to move from place to place. Here is a 1MW system of solar panel (10 x 100 feet) at 32% efficiency (432 w/sq.meter) is 432,000 kW, one on each side, one to the front and two on the back. 1t per panel at 4 panels. 1.73 MW for 4 tons at earth not at Mars (0.69 MW) . This ship is chosen because it minimizes the specific infrastructure devoted to panels, which becomes really problematic for very long panels. I want to say that 1000 sq. meter retractable solar panels are a fantasy, they do not exist. Here is a reality check. https://www.nasa.gov/content/solar-arrays-on-the-international-space-station. The solar panels on ISS generate total 120 kw of electricity from 8 @ 35 meters x 12 meters. That is just 36 watts per meter, that is really happens and we are planning based on solar power densities a magnitude higher. Each solar array and truss weight 15.8 t and thus 62.4 T are required for 120 kw of electricity ~2000 watts per ton. https://en.wikipedia.org/wiki/Integrated_Truss_Structure#Truss_subsystems So when I start with 400,000 watts per ton it means I am provisioning power at 200 fold higher density than the current most reliable application (that is to say an application used to support the lives of humans in space over a prolonged period of habitation). Next we look at ION drives. Here is the highest TWR drive in existence. " The pre-prototype HiPEP produced 670 mN of thrust at a power level of 39.3 kW using 7.0 mg/s of fuel giving a specific impulse of 9620 s.[2][4] Downrated to 24.4 kW, the HiPEP used 5.6 mg/s of fuel giving a specific impulse of 8270 s and 460 mN of thrust." wikipedia. Here are the structural statistics. .41m x .93m x 0.15m means the unit is 0.3831 sq. meters (estimated weight between 10 and 20 kg). This gives a rated thrust density of 1.2007 newtons sq.meter. The weight per square meter is between 0.026 and 0.052 kg per sq.meter disregarding framing. The power is 63 kw per sq.meter. In the above we have 1.73 'handwaving' megawatts. this requires 27.5 sq meters of thruster or a circle of trusters 3 meters in radius (very doable) [that is to say 1.6 larger cross-sectional area of the largest engine in stock KSP. The engines will weigh ~1.5 tons with adequate trussing. The force production is 33N. So if we had an ounce of fuel (and all the controls were physics-less) we could generate a TWR of 0.000611. This is 6 ma of acceleration. So on our bare bones Mars mission (we carried a quart of earthworms living in a 1 kg container) we need 2 @ 5760 = 11520 dV to go and return. In this situation you will need 0.92t of fuel and 0.093t of tank. The TWR drops to 0.000523. Fuel and fuel tank are now 15.9% of ships weight (you thought the ISP was too generous). To break earth orbit would require 30 days minimum using efficient kicks. So the next thing is we need a minimal computer control module. Lets say we need a decent battery - 1 ton (we do, burning between AtP of 160 and 020 requires a battery, even when using kicks), Command and control, communication, rcs, reaction wheels 1 ton. So now we are up to a base weight of 7.5 tons. The amount of fuel&tank is 1.23 tons. TWR = 0.000383. 50 days to escape earth. So now we want to go to mars in 89 days and return in doing so we need 58k (m/s) dV of fuel on this very simple earthworm ship. Lets see what this very efficient ship offers up: Fuel is now 60% of the weight (remember you complaining about ISP being to high!).fuel&tank are now 9.86 tons. (5kg/8000 USD means 15.7 million USD to get that quart of earthworms to mars and back). TWR = 0.000204 Days to escape earth assuming thrust is on 25% of the time . . . . 75 days to escape Earth. We move onto humans. . .that is to say Elon Musk. The ISS weight 419 tons, but we only need on section of it. So lets at 41.9 tons of weight and recalculate. This allows the transport of 1 human (On ISS 6 humans live in 10 livable modules so . . . . ). So here we go . . . . . Weight = 100t. . . TWR = 0.000031. 59.5 t of xenon used (~100M USD). Assuming a quarter of each orbit burning to escape earth or Mars (3398 dV/(.25*.00031))about 500 days to exit Earths gravitational influence. You are not going to Mars in 89 days. ISP of 9000 is not too high, to get to Mars in 89 days and return you need alot of power and a very high ISP thruster Lets now replace those solar panels with an 1.724 Megawattage of ISS panels. 62t * 1.724/.120 - 4 = 886.333 t. TWR =0.0000013, Xenon used is 1119 t (1.8B USD). Total weight is 2kT. Elon died of old age before reaching Mars. Its like this, getting to Mars in 89 days ranges from practically impossible to theoretically impossible. To leave in earths SOI in 50 days would require a 17.24 MW ship. To leave in 5 days would require a 172.4 MW ship and 400,000 square meters of '1kg/sq.meter' solar panels, and that is with panels we do not have (and dont BS that they exist, until they have been applied to a human ship, as far as we are concerned they do not exist). Fusion we do not have . . . . Fission cannot produce anything near the power required. Radioisotopic thermal generators are too small . . . .We have only to consider making solar panels much more efficient, structurally sound at a lower weight. THis group is old, we have seen the 39 days to Mars (of VASIMR) which has been debunked, we have seen other claims, mostly debunked, this claim is not exceptional. Electric power is great, but only if you can get the electric power/weight ratio up by magnitudes over what it is now, and even so its spells worlds of trouble with wiring and cooling systems.

Good absorbers are also good emitters. https://en.wikipedia.org/wiki/Thermal_radiation If it absorbs all the visible light it will have a beautiful infrared signature. Here's how to do it. 1. Build a reentry ship made of two section, one is to get you to pE which is say 100,000 meter minimum. It has an engine that fires at PE allowing it to escape the the planets orbit and return to interplanetary space, in the fog of re-entry it would be very difficult to probe the ships KE versus altitude. The ship should be fusiform and should point nearly directly at PE as it enters. It should have a diffuse reflectivity and an A of about 0.7 (not shiney). 2. At the rear of the first ship is a second ship of much lower density with detachable friction brakes that cause this ship to stick into the atmosphere once it detaches (about 140,000 meters) it will have an injection force of 50 a/kg from the first ship and its added drag to weight ration will cause it to reenter. The single person craft has a thin shell, as single person in a minimal suit capable of survival for 20 minutes, a parachute, a light weight dirt bike, a several cans of sealed gasoline (that can be opened on landing), and a shovel. Next the reentry will occur over a desert in the mid afternoon period when the that desert is its hemispheres summer (lets say on the border between chad and libya, masking the heat signature of the entering space ship. As the ship slows down the parachute comes out 500 meters above the ground, and once landed the human inhabitant removes the suit, takes 2 days worth of food rations, the gasoline and straps it to the dirt bike. Using the shovel he buries the heat shield, the parachute, any rcs thrusters used to decelerate during burn, he disassembles the frame of the ship and buries it and finally he buries the shovel with his hands. Next he travels to the closest body of water, empties the gasoline (or ethanol which can also provide calories) from one can into his tank, he uses a small portion of citruline based soap to clean the container and then filters the water and fills the tank. Having completed this he once again takes off, using hiways or backroads until he reaches a municipality where he can blend in. Within 10 miles of the outskirts he goes off road and then buries the dirt bike and begins to walks. Knowledge of dump is a good place to find clothes that fit the people in the municipality. He should also have small quantities of platinum or gold which he can see to a Jeweler. (By now knowing the language of the land is a must, and I assume he has plastic surgery to alter his appearance to fit that of the place he landed). To summarize, absolute stealth is not needed, but low profile and entry somewhere that has low strategic value. Then move from low strategic value area to target areas by stepping into gradually more secure areas. THere are hundreds of objects that burn up every-night, security agencies can't afford to monitor everyone, an ICBM headed down over an uninhabited area (like the explosion that occurred in the South Atlantic in the 70s) are not likely to be of great interest until well after the fact (as in who did this, lets study the issue and find out).

Mercury-Sun L1 (la grange point). but disk has alot of pressure due to the proximity to the sun and instability at L1 due to solar wind. The sun is 0.28 the distance from the sun relative to Earth at its periapsis. The amount of radiation hitting Mercury is more than 13 times higher. A piece of aluminum that reflects 80% of radiation would heat to an incredible 1/2j = 0.2x5.78x10-8 * T4 where incoming energy is 16800 w/(sec*m2)at periapsis. T = 923'K. Any film that would absorb the suns heat would melt in seconds, carbon-fiber would denature. Aluminums melting point is 933.47 K, and I think aluminum would not be stable. You could decrease temperature by increasing the radiative surface area on the back side but that would significantly increase mass. It would be easier to move mercury further away from the sun. You can't terraform mercury, the atmosphere is to thin and it does not have enough gravity to hold an atmosphere, it is, in essence a moon orbiting the sun. You could however live in a depression near one of Mercury's poles, it has water (ice), minerals, CO2, etc. Mercury has alot of energy for colonization. The problem is however the structure would have to be entirely enclose.