PB666

Permanganate, H202 is not stable in high concentrations, better at low concentrations with a stabilizer. We don;'t actually consume that much O2 per day, if you think about it the amount of dry carbon in our food is probably on the order of 100grams a day so for 500 days you need roughly 2x 100,000 grams or 100 kilos of O2, considering its importance not that much in a 10tonne vessel. The bigger problem is getting rid of CO2, if you could seperated from the air you could just dump it into space. CO2 is much less volatile than the other gases, so thats a LiOH less method. Before you suffocate CO2 will get you first, major headaches, cramping, etc.

Yeah, need to take a leak stick your thing into a minature airlock and relieve, toilet gets flushed into space accelerated by fermented sewer gases. Think of what space would be like in say a couple 1000 years. "Captain the ship appears to have been abandoned ". . . . . .squak comes over the comm "Coprolites! [bleep bleep] kills every time, right through the hibernation chamber"

Landing is the reverse of liftoff but with a finite end-point, and if you get it wrong it will be the endpoint. Chinese show you how to land on the moon, thats the way to do it, no problem, microprocessors and GPS. But if you are seriously mining the moon, then lift off is going to be more costly if the mats are intended for orbital use.

It all works well until you realize that the axis of the ship is facing the hv source, and it limits the number of panels, that you want a power that can accelerate at 1g for 1 year (or 0.1g for a year) and those ION thrusters waste most of the energy as reaction mass energetics, and you are lucky to get 0.001g and you would need to accelerate for 10 years, by which time your ship is way out of the resolution limit for the beam. So I figured for a beam powered ship to work you would need a collective of light harvesters in the Inner solar system that beamed light to object near pluto's orbit, this is then stationary enough to beam light to a ship, it would send out polychromatic light so the ship could steer itself back to the center of the beam, when the beam ship moved far enough from ideal another orbiting ship would be employed. If we discount the ISP problem outlined in this thread (meaning no way to carry enough gas to reach anything close to c) The critical problem with this is that when the ship finally reaches its speed. 1. Light reaching the deceleration zone would be tiny 2. Assumed that earth maintained interest 200 years later and kept sending light. In fact this is the problem with nearly all near light speed how to stop if by some strange luck something 1/1000th c is achieved. They all have the same basic problems. Large slow ships can utilize celestials within the target system to help reduce velocity,

I liked the queen, every good sci fi needs a vixen queen to tweek the latent, Oedipus complicated sexual desires of sci-fi nerds. 7 of 9, beta-sed seriously what do you think the producers were going after. I always like in star trek when they wanted to make the women seem beautiful they would make them look all fuzzy. Ask yourself what happened to SGU, then look at their story lines. Are you complaining, most of the space stuff now a days is CGI, they used to portray the enterprise under attack by bouncing up and down on a fishing line. Of course then we can also beat up on lost in space.

That is the idea for the interstellar ship, but that is beyond the scope of this thread, this group, this century, and probably this millenium. Beam of course means hv, which means collector, most panels can function at 10 times irradiance so all your doing is reducing the panels by a factor of 10.

What is the lunasynchronous altitude, i dont think one exists. You can use earth-moon lagrangian points however. Since the moon is tidally locked to earth. However consider this, the moon has no atmosphere, surface gravity = 1.62 m/s2 the gravitational accel. u is 4.90E12 and radius is 1738 km, orbital velocity is thus SQRT(u/r) = 1678 m/s. It doesn't take much to accelerate to orbit. If you has a craft with a decent thrust to weight ratio (say 0.45g) all you need to do is take off on a ramp of say 20% 100 meters and you have enough vertical velocity to make orbit before it falls back to the moon. You don't loose much energy returning to lunar orbit because you don't have drag. Building a ramp 100 meters long 40 meter high and 10 meters wide is alot easier than building a rope to L2. If one could have precision ascent one could literally create a electromagnetic track that accelerates the craft at 3 g followed by an acceleration pretty much along a shallow trajectory 10 to 20% at 0.5 g, very little energy wasted in the accent fighting gravity.

I don't see radiation of alpha, beta or gamma as a problem. A sheet of paper stops alpha, beta a little further, and the complex materials used to build a craft is not a real problem. Nuetron radiation can be a problem IMO during two phases. For example when in a equitorial orbit the craft once per orbit it traveling tail first in the direction of the sun, during this period neutrons will be emitted from the rocket nozzle and will continue to fly strait, however the solar wind can deflect them and send them back into the space craft. Boron infused metals in the craft hull can stop this, but during occupational EVA's they would not protect the nauts, nor protect them during transfers. I agree with the poster in that there are concerns about long-term Use of Nerva. I think Nerva was proposed as a method for getting things way far away from earth, As in a New Horizons like launch were you do a major burn directly out of earths atmosphere. In this situation a craft reaches 95% of its orbital speed, decouples and then fires the nerva rocket placing it on an sol elliptical escape trajectory from earth. It has never been tested in a situation were the engine would be re-engaged 3 months later. My suspicion is that once the Nerva finishes its 3 hour burn, the engine and tank would be decoupled leaving a payload to travel on. Liquid hydrogen . . . A typical 160 L liquid nitrogen tank boils off over 2 months, the larger the tank the smaller the surface area to mass ratio. Without convection the hydrogen boils more slowly. Since the tank is huge you can invest considerably more for insulation, HOWEVER, one has to be very careful because there is a tradeoff between strength and conductivity. Let me give and example. lH2 is extremely cold and expansion differentials between the tank and its extratank welds are stressed by the temperature differential. We can bolt the tank to a low conducting material such as carbon fiber frame for the tank, but the connects are going to be the same temperature as hydrogen unless the tank is of the double wall evacuated design (like a dewar), (which means that the most secured parts give little support to the metal with highest inertia, it is free to bounce with stresses. Space is liquids will not behave as in a dewar. If it is stored in a double walled actively evacuated container then periodically the hydrogen can be evacuated, recompressed or kept in recovery tanks were it can be used first. So thats not a big problem. The big problem is you need a massive double walled tank with little bottom support for a 2G launch that is also evacuated, creating even more pressure on the top of the tank. This could be dealt with if Carbon fiber standoffs are pressured into between the walls of the dewar. Again these will shrink so basically the tanks you have to be assembled weld by weld at very cold temperatures to kept cold until filled. So maybe somemore tech for lH2 needs to be accomplished to bring up that capacity. Now we get to the issue of will hydrogen store until Mars portion of the missions is over. Lets think about this, if we could solve this problem we would not be talking about hyperglolic use for Mars lander, right. So its important. If we are talking about hydrogen as the primary ejection mass, its a problem, but if we are talking about hydrogen as a payload on SEP then during the transfer we have all the solar power in the world to reliquify hydrogen, so thats not a problem. If the Mars mission is a few day mission, your liquified gases should be OK (after all Mars irradiation is .4 of earth, its colder and its atmosphere is very thin). But here again if we are talking about a lfOx scenario on Mars (cause the Nerva does not have enough thrust to mass) then we already have a transfer engine and if we have a means of storing H we also have a means of storing O and so we don't need the added weight of a Nuclear engine. So now what is the best way to get from Earth LEO to Mars? for an ISP of 1000 maybe Nerva is not right, but what about ISP that can be scaled from 1250 to 9000. My thoughts here are on the return we could use ION drives to ship even poorly stored fuels to Mars and then they could be liquefied and transferred in Mars orbit for the journey home. Even at 3 or 4 times payload to shuttle weight the high efficiency SEP can transfer fuel as long as you allocate the time required to get from LEO to LMO (say 2 years). Again you could, theoretically use solar in the unused part of the flight to reliquify hydrogen indefinitely. You could literally park hydrogen in orbit or L1 of Mars and send gassy hydrogen on Ion driven shuttles for years waiting for a manned mission to support. The problem is that the refrigeration systems on the ISS have been a major source of repair issues. The parts are necessarily mechanical and wear. The bigger problem, unless you remove the CFC restrictions many of the modern cryogenic gases are not really designed with equipment longevity in mind (another phrase to describe them would not be appropriate). We had a -80 chest freezer from the 60s that we finally disposed of ~2000 it lasted about 35 years, both of the -80' Freezers we have bought failed just after the 5 year warranty was up and 8 to10 years is typical. For the really low temperature freezers you need to replace condenser line and the oil/gas separator every 5 years or the particulates from new-CFC degradation tend to clog up the lines. I know of people who take the old refrigerants and clean them up just to keep these old ultralows going, they are considerably more reliable than the new stuff. (seriously so few freezers are ultralows allowing the old-CFCs for this would not have even dented the Ozone layer, but . . . .). There are ways around the problem, for example more robust but wasteful seperators or back-up solenoid operated condensation lines, etc could create a fall back position.

Lets not get this thread locked please. Remember there are defined and common uses of words.

Before I start I need to define my terms F = force (measured in Newtons, N) M = mass (as in vessel mass or fuel mass) M* = mass ejection rate (M/sec) kW = 1000 watts = energy production rate or 1000 joules per second. Power = Power available (Kw) Power efficiency = Power not wasted Heating = Power wasted Irradiance = Solar output measured at 1 AU , 1361 Watts per sq. meter Panel efficiency = percent of irradiance converted to electrical power ISP = Fthrust / M* this value is 9.802 x ISPg (sec) which I will not use because basically it adds a term to every equation not needed, particularly for a craft that is interplanetary. ISPg is best applied to chemical thrusters, when you don't really care about where ejection force power comes from, you can wave your hands about bond energies, etc. Given ISP: M* = Fthrust / ISP ION drive equation is F = ( 2 * Power efficiency * Power ) / ISP Given: ION drives cannot shift ISP more than a 4 fold range Given: HiPep produces 0.67 N (rated) at 39.3 kW at 9620s (94300 v) between .75 and .8 efficiency. The form factor is .31 x .91 x .1? = Assuming density of 2 and a fill volume of 0.1 the Mthruster = ~5 kg. Thus one can estimate the following: N/area = 2.37N/m2 F/power input (N/kW) = 0.67/39.3 = 0.017 N/kw at 93000v. For the sake of simplification I will use 0.015 N/Kw at 100000v. Thruster modification cost for on the fly down-ratable ISP (ISPdr; arbitrary guess) = k * SQRT(100000/ISPdr). The cost is paid assuming that the thruster is built for 100,000v (10202 s), and therefore added cost is to allow it to achieve lower ISP during the trip. This allows a significant burn say at Perigee allowing a kick then a higher ISP on a second pass and then most efficient ISP to reach Mars. While these numbers appear not to have much value . . .we then can add solar panels Maximum panel efficiency is 40% lets assume that this applies to non-atmospheric, then we can apply the following: Irradiance (kW/m2) * Panel efficiency = Output power per sq. Meter 1.361 * .4 = 0.544 kW/m2 DC. If we assume this is 24V we have 22Amp so we need 10 gauge wire to feed the power center of the space craft. We are going to take a base assumption that 1 square meter of panel weighs a kilogram. Therefore the space craft has a minimum of 1 * thruster weight. So lets build an ion driven space craft, to keep things simple we will choose a spacecraft that with 1 meter squared solar panel 0.544 kW (panel output) x 0.015 N/kW (thruster input) = 0.00816 N. This then consumes M* of 0.00816N/100000v = 8.16E-8 kg/sec. We have alternatives. We have a theoretical weight per thruster of 5kg per .67N = 7.5 kg/n * 0.00816 = 0.0612 kg With our panel we have 1.0612 (Assume the microelectronics the thruster is glued to the back of the panel) ISP Thrust (N) M*x10E-9 duration/kgfuel 100000 0.00816 81.6 141d 50000 0.01632 326.4 35d 25000 0.03216 1305.6 9d 12500 0.06432 5222.4 53h 6250 0.12864 20889.6 13h As of yet we do not know our dV. Two reasons for this I haven't added any fuel mass. Nor have I added any structure and control mass. Our theoretical acceleration is very close to thrust since solar panel of 1 kg dominates the mass. Thus we can readily determine our theoretical maximum for each ISP. In this case I am going to add fuels and mass of 1.2 and tabulate the accelerations. To do this I am going to assume that for every kg of fuel added 0.2 kg of structure is added. With our theoretical ion drive we have then 1.0612 + Fuel*0.2 = dry mass, starting mass = dry mass + fuel mass + tunability cost mass. The equation is ISP * ln (full mass/dry mass) ISP (ISPgo) 0.1 kg 0.5 kg 1 kg 2.0 kg 4.0 kg 100k m/s (10ks) 8845 C 35808 58383 86235 114713 50k (5.1k) 4325 D 17581 B 28753 42622 56896 25k (2.55k) 2143 F 8725 C 14288 B- 21210 B+ 28353 12.5k (1275) 1058 F 4317 D 7082 C- 10534 C+ 14100 B- 6.25k (637) 519 F 2127 F 3498 D- 5218 D+ 7009 C- 3.125 (318) 253 F 1042 F 1719 F 2575 F 3472 D- The first gets our craft from earth LEO to Mars LEO and back, but over a period of 200 days and of course the spacecraft does not carry any payload to speak of, the second gets us close to Mars, the third gets us to a geosynchronous orbit (or so). With 5 times as much fuel the third ISP gets our craft to Mars. In the second fuel column the starting mass is one/third fuel, and even with that mass the ship is unable to return from Mars with a decent ISPgo of 1275 sec (almost 3 times the SSME ISP). With 1 kg of fuel it makes it back to Earth's sphere of influence (however with any additional payload, its stuck at Mars). One of the things that I did was under-engineered a decoupler on the Gas tanks so that tanks are used serially and then discarded, this gets rid of 10% of the structural cost, but backbone cost still remain 10% of the tanks weight, this improves the ISP for heavier fuel loads a little. I have assigned a grade based upon the usefulness of each reaching Mars assuming it uses 1 ISP and does not refuel along the way. But we can pretty much assume that a ship that cannot even break earth’s orbit or reach L2 refueling or extra-lunar refuelling point is of little value and can be ignored. Consider than in a manned Mars mission at least 1/3 of the ships dry mass will be devoted to survival and other related activities. So at about 4500 dV even refueling will not help with humans onboard. The problem with more fuel loads, are two fold, the through put of the thruster (electrode wear and tear) and breaking Earth's orbit. So lets look at the (get the hell away from earth) accelerations. Lets keep in mind that unless we like leaving our astronauts for months in LEO and LMO for no particular reason, we need to be shooting for accelerations of at least 1mN per starting mass second. Lazily (and to control column widths) I will use the mm but you should assume that is mm/sec2. Parenthesized numbers assume a humanized payload addition of 30% , the second number describes how many time the vessel would need to be refuelled to go to Mars enter its low orbit and return. ISP 0.1 (HPL) kg 0.5 kg 1.0 kg 2.0 kg 4.0 kg 100k m/s 6.9 mm (5.51, 1) C+ 4.9 (4.1, 0), C 3.6 (3.2) D 2.4 (2.1) D- 50k 13.8 (12.9, 2+) B+ 9.8 (8.3, 0) B- 7.2 (6.3) C+ 4.7 (4.3) C 2.8 (2.6) D- 25k 20 (17, 0+*) B 14.4 (12.8) B+ 9.4 (8.7) C+ 5.6 (5.3) C 12.5k 39 (33, 3*) C- 29 (25.4, 1*) A- 18 (17*,0+) B 11 (10.5*,0+) B- 6.25k 38 (37*,1+) C+ 22 (21*,0+) B 3.12k 44(42*, 2+) C * if one pays the thruster cost here then the acceleration only need be used in LEO, and scale ISP to the dV need to alter a profile, possible to reduce the refuels. Based on this the very best choice here is a ship that can achieve 25000 to 100000 ISP (2750 to 10202 ISP) and keeps the humanized portion of the payload below 0.3 dry mass. About the same amount of fuel as solar panel and the bare minimum of structure. I can Imagine a ball, with two bars sticking out and solar panels. Though I think probably given we need to add structural weight, 1.5x fuel might be better. So if this is the case suppose for a multiyear trip how much weight. Lets say 10 tons per astronaut, sounds pretty small. So our scale is 10000/0.3 = 33333, for 2 nauts that is 66666 How does this equate: 66666 meters of solar panel at 66 tonnes producing maximally 36 mW of Power. I should add that if one uses my 10 by 100 meter solar panel (KSP creation) that is 66 Solar panels. The thrusters 11.5 tonnes produce 0.543 to 4.3 kN of thrust (double the PB-ION) and also produce 8.125 MW of waste heat, that needs to be dissipated. The thruster footprint at 0.1M height is 153 square meters (a circle of radius 6.9 meters radius). Saturn V rocket has a radius of 5.1 meters. Our payload in LEO weighs 190 tonnes. Saturn V = 140 tonnes to LEO. Now judging by the structure, it has to be assembled in space.

http://www.compoundchem.com/2014/07/25/planetatmospheres/ Technically if hydrogen is metallic at high pressures its no longer a gas.

http://www.engadget.com/2014/08/18/nasa-origami-solar-panels/ I was going to add this to a pre-existing thread that would have been perfect for this topic, but for some reason moderator locked it, if said moderator feels the urge to unlock the thread, then please merge this post with that thread.

A boat is not planks, a boat is a buoyant vessel, it can be made of any number of materials. An infinite number of things did come into existence with the universe, unfortunately you would not recognize anything. When you talk about infinitely hot, its so hot the temperature is immeasurable, matter is purely in the most energetic forms (meaning there is no rest mass). Homogeneity takes place when things cool down, but then heat back up again because of star formation. If you start the universe with something called a quantum singularity, it which its existence is govern by the purist form of quantum mechanics, the difficulty is that the universe is in an infinite number of states all at once, but that means little because time as we know it does not exist, the progression of time and identity of space have meaning when space-time begins to realize. Imagine it a little bit like this here you are, to keep you alive we put you in a U.V. shielded glass bubble and ship you back in time in a magic time machine. About the time we reach deionization state a protective x-ray shield is added, and then we have an antimatter, neutron and anti-neutron deflector. Next you may note that neutrinos are starting to make you sick, we have a special drug for that, then some very exotic particles appear, the strength of all the hv shielding needs to be increased, your bubble itself is expanding and a rich array of exotic matter is filling the bubble, and then you and the bubble cease to exist. The point may seem meaningless but consider that a universe at its very beginning has little meaning to us, it is rich in things that our age is incompatible with. Many exotic materials existed in that period that science has not yet characterized, but its for acedemic meaning only (at least until humans learn how to harness much more energetic sources of energy).

[Facepalm] Here we go again. I just want to remind everyone that the Saturn is a 50 year old rocket, we are talking a half of a century ago. Why don't we talk about a double decker DC3 in stead of a 747, lol.

As long as Jeb has the back to push, I always have enough fuel. lol.

Photonic rocket would not, remember the equations 300MW per newton. You would blow most of your energy in the waveform of the photon. You need reaction mass. It takes a year at 1g, (thats 9.8 meters of acc) to get close to c, So if your ship weight 32500 tonnes to get to 0.17c in a year, bad news that is 54,150,000 N/s x 300 MW = 16 terawatts of power, all of which would have to be processed into light. You want to accelerate a mass, the more mass you accelerate the better, unfortunately you have to carry it with you. Simply stated by current laws of physics, carrying warm bodies around at 0.17 is not possible. I think interstellar travel, if it ever happens is going to occur either as probes or as large biospheres that can afford the long transit times. Either that or humans live long enough as a species that we catch a ride on close passing stars.

Also bad ideas, 1. picking up loose change on a busy freeway. 2. Pull on superman's cape. 3. Messing around with the ole long ranger. 4. And of course you don't wanna messa'round with Jim.

Oh boy here we go again, its a free world but . . . . . . .

There is no such thing as a pure matter/antimatter propulsion system, unless you are proposing using the Cannae drive or a photon drive. You need a reaction mass to create thrust. Any system that does not include this is a non-starter. The photon drive is 1N per 300 MW of power, you would lose the lions share of energy if you chose a photon drive. You need an antimatter plasma containment field, it requires you to split the antimatter into positrons and antiprotons, then spin them real fast and keep them from touching anything. The toroidal fission reactors appear to be able to do this and should work for antiprotons. How you store positrons is your guess. .17 would be theoretically 216.75 tonnes of antimatter however we are not considering the weight of ejected material, so called reaction mass. To gain momentum you are going to eject something really fast and dP1 = dP2 so if you eject that mass at 0.5c (say 1 tonne) not factoring the dilation effects, 0.5 x 1 = 7500 x 6.6E-5 . . . . . . . won't work. One thousand tonne 0.5 x 1000 = 7500 x 0.067, that gets you to almost 30% of your goal, so lets say 1250 tonnes of antimatter and 4000 tonnes of accelerant, for a total ship weight of 12750 tonnes. In addition, you have no way to block he destructive effects of space dust at this speed, or too stop when you get to your destination, now we are talking about 20000 tonnes or more . How about the energy required to store antimatter for the years of space travel.

Then you haven't been following the discussion, 70 kW of power per newton of ion drive thrust. So if you are using an electric drive, you are basically dealing with the need to produce alot of power, although the drives are around 90% efficient if you take that as 1 part, then 1.111 parts is the absolute efficitive energy efficiency and therefore even at 41% there are 2.71 parts per N or 189 kW of waste heat. Say you want 100N that 18.9 MW of waste heat. In addition these reactors are heavy and dangerous, the russians have already lost a couple, one exploded. So you add weight for reactor, weight for heat transfer, after about a 0.0001g of ac the weight of added supply super exceeds the benefit you get from energy begins to start saturating. At least with solar I got it up to .00025g Nuclear as a power source for ion drives are no-go from the start, forget it, it will not work. Nuclear thermal rockets are a better choice; HOWEVER, they have never been tested after being started and then being reinitiated after 6 months. Once the fuel is activitated you cannot stop it from producing tons of heat, and that would eventually degrade the engine. So you would have to carry return trip engines once you get to your destination and jettison the first engine. Nuclear thermal could be used on the burn out of the solar system. ION drives have been tested and operate for years and years in space, and the newer models have less of a problem with electrode degradation than the older models. Solar could be used in conjunction with nuclear thermal using rf generators and/or lasers to directionally accelerate the fuel even faster. It could potentially use less nuclear fuel but run at a much lower thrust. ION drives have ISP now 2.5 to 4 times that of NTR. This is particularly advantages because leaving earth LEO and returning takes 19,000 dV. Thats alot for a single stage system and the NTR with the same amount of fuel is only going to get about 12,000 or so dV, though some of the new designs promise higher ISP. What that means is for NTR to complete the trip you need more than one stage. I am assuming that the lander is shipped to lower mars orbit by a robotic ion-drive ship and the landers weight is not apart of the mission. Adding a lander to the NTR ship weight basically makes the mission impossible. My test bed system, I have really focused on keeping the acc above 0.0002g which is satisfactory for producing the dAlt/t that would suffice to break and control exit into earth mars space in a reasonable timeframe, it takes 39 days (much less if the ION drive could get a fuel dock and boost from LEO with its iondrive assist. Add that to the <170 days to transfer. Just getting a ship to 2 earths radius (13,000 km) is useful because the sunblock time is much lower orbital velocity is 30% slower meaning that the time spent close to optimal burn point is higher, less burn wasted in a closely packed spiral.

HIlarious. Although to be fair, that shuttle is a bit bigger than stock parts.

I dont what Nuclear system they claim is part of the fictitious vessel, but any nuclear system so far designed lacks adequate power and would require cooling massively more than the drives could accelerate.

Read this for more details where the valley ice resides. https://en.wikipedia.org/wiki/Mercury_%28planet%29#Surface_conditions_and_exosphere If you land on a sun exposed surface, there is no water. If you land on the night non-polar there is no water, buy your could land on a sun non exposed at an elevation were you could poke up a heat exchanger, and get heat, and close to the poles this is were plasma that has struck mercury and slowed down. Start with plasma traveling 250k m/s it will not form water, it strikes mercury's surface and slows down to hundreds of miles per hour (the energy goes into the surface and is radiated back into space), it is still plasma but flux back and forth into hydrogen, water, other compounds, the flux is from the hot to cold side and from the solar wind facing to gas abating edges. As the gas rolls around the edges the temperature falls from 700K to 100K but around 200K and water and ammonia that has formed begins to sublimate and gravitationally falls into the craters, since these are polar it remains in the craters until the next major asteroid impacts mercury. Likewise any ship will experience perpetual day are night depending on where it lands.

Do a search, we have done the calculations, it would take millions of years to harvest enough hydrogen from the solar wind even at mercuries orbit to fill a hydrogen balloon, let alone harvest for use in .. . anything. The sun produces alot of hydrogen, true, but it does so over a very wide area and that hydrogen speeds away at a million km per hour, it eventually slows down as it runs into things and cools down, but basically blasts anything volatile in the inner solar system (e.g. why tails on comets point radial) its not alot of plasma, but anything moving at a quarter million meters/second is going knock the bejezus out of anything it hits. So eventually enough of this gas slows down out in plutos orbit to react forming ice and weird whatnot molecules of the outer solar system. This is where you harvest the hydrogen, but not real time solar wind, but condensates from the last 5 billion years. Theres not alot of it either, if there was new horizons would be toast, its found scattered on various protocomets out in the kuiper belt. The overwhelming majority of the hydrogen after spending a few weeks speeding away from the sun slams into the bow shock and ends up drifting out into interstellar space. When you see reports of a plasma storm on the suns surface that is millions of degrees hot, think velocity as in not much substance but a hell of a lot of speed. Good idea, one side of mercury is unbearably hot, the other side is unbearably cold. But yeah mercury would be a good target for some brave explorer, if he can manage to land in a shielded valley whereby he can place a mirror and deflect some of that sun light for his use. Diffraction gradient also works. In these valleys there is ice on the valley floors, easier to mine ice than gas.

So I have done somemore homework on this problem, I think I have your Earth to Mars transporter here What is special about this ship is that it has 12 @ 10m x 100m solar panels. I have up the efficiency so that they produce 450kW per panel (as opposed to the perfect 1300kW that is delivered by the sun) The 80 @ 1 N thrusters produce use 5.6 Mw of electricity; the panels produce 5400 Mw and are non-tracking, the 20000 units of battery deliver about 4 sec of power, at this power consumption batteries are not useful. There is enough Xenon 50,000 deltaV. This setup delivers while sunfacing 2.5 milimeters, to break earth orbit you need approximately 3000 dV from which means a perfectly lit ship can do this in 1.2 Msec or 13 days. However because it cannot store power, it can only thrush from behind the earth at considerable distance and close to earth along the sunfacing radials. This effectively cuts that time to about 3 fold higher or 39 days. The Mars dV is ~900 m/s since the ship is almost perfectly sunfacing when it begins its acceleration off of earths SOI (although behind the earth is almost a million miles away) it can achieve this in 900/0.0025 seconds or 360000 (~4 days). Since the 39 day trip it would have to be accelerating for half the trip or 19 days the most (however we have lost 6.5) so basically we on have 12.5 days to accelerate which roughly means we can only choose a transfer that permits a dV up to 2700 this severly limits the options to much greater than 39 days.