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About Frank

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  1. Right & left handed tools...

    Top picture is right handed, bottom is left-handed (goofy in snowboarding talk). Tool goes in the dominant hand. I didn't know they sold them the other way without labels, that's weird.
  2. Right & left handed tools...

    First image looks goofy to me, but might actually make seeing the cut easier. The tool might get in the way in some circumstances and the weight should be on the held piece, not the cut-off piece.
  3. Large Hybrid Model Rocket

    CO2, but it might work as a general pressure vessel compared to rolling your own?
  4. The reformer can work, and the combination is currently more efficient, as you say. Work is still being done on DMFC and SOFC, so it depends on the outlook of your idea - near future or further down the road. I was responding to the PEM in all FC vehicles question, answer is that it is currently most efficient, developed and cost-effective I guess. I don't see hydrogen as a viable automotive solution due to storage and energy density and even methanol isn't strictly GHG free, though portability and energy density work in its favour.
  5. Large Hybrid Model Rocket

    And paintball was too small?
  6. Methane the same way hydrogen can be "created" from a wall-mount unit in your garage. Well, there are direct methanol fuel cells, so a reformer would not be needed. Efficiency might not be there yet. Methanol is easy(tm) to store, compared to hydrogen. There's a whole "methanol economy" movement (a vision at least). Home Hydrogen Fueling Stations - Overview | Hydrogen Cars Now:
  7. Methanol is certainly easier to handle. Wonder if a methane to methanol gizmo that fits in a garage exists or can exist. That would get around the availability start-off problem. A way to use water to convert methane into methanol:
  8. Large Hybrid Model Rocket

    Did you look at SCUBA diving tanks? e.g.
  9. Best path to lunar provenance propellant?

    A good point has been made that oxygen is certainly available on the moon, so that a kickstart process might go for the perhaps more straightforward but more energy intensive path to resources than trying to figure out how to extract water from a resource of unknown state, ice or hydroxyl, concentration etc... So land solar panels, a chariot rover bulldozer, maybe a robot arm + android (cherry picker and human analog) and extra batteries, plus an oxygen extraction "machine". If this machine can either make bricks or sinter the regolith surface in place, while extracting oxygen, we can tele-robotically prepare the landing pad, habitat foundation, and roads while extracting oxygen. Hydrogen would have to be sent from earth. delta-v to EML1 or EML2 is 2.52 km/s, so it would take less than 1/5th the mass in hydrogen to bring lunar oxygen to EML points. Assuming 450s Isp and 5% ship mass (rough estimate). At the very least, oxygen won't need to be sent from earth. Hydrogen instead of water (8:1) mass savings or 11% the mass. Fuel for a return trip is 6:1, so 15% the mass compared to bringing hydrogen AND oxygen. Once humans land on the moon, tele-robotics lose the 3 second delay and 3d printing can be used to adapt machines to extract resources. Transportation Architecture for Cislunar Space ssp2015-sowers.pdf:
  10. A perspectives of the heat pumps

    A search of "sweden ground-source permafrost" brings up links about permafrost melting due to climate change. Do you have a link about them being banned?
  11. A perspectives of the heat pumps

    Just to expand on the points you brought up, heat pumps are a key component of going fully fossil free. Especially in colder places, ground source heat pumps make some sense. District heating was common in USSR IIRC, and converting large plants to ground-source should be easier than trying to do each individual home. (If I were king, emperor or ruler) I'd like to see large new buildings built to be fossil free in this manner and large subdivisions built with shared ground-source loop access run through individual heat-pumps. A search on distributed ground-source came up with this link: heating - Why aren't Geothermal heat pumps more common? - Home Improvement Stack Exchange:
  12. Best path to lunar provenance propellant?

    If I understand the process, gases are blown by solar winds from the earth to the moon, so it's trapped earth gases and not a finite resource. Also, if we don't use it, who will? Is there any benefit to anyone not using lunar ice? I have to admit, this wasn't something I gave much thought...
  13. Best path to lunar provenance propellant?

    Oh, hydrogen boil-off and insulation requirements - gotcha. Methane helps there too.
  14. Best path to lunar provenance propellant?

    Losses? I'm a bit confused, can you elaborate a bit? A process for extracting oxygen while sintering regolith into bricks exists, as does a process while smelting regolith for its resources IIRC. Oxygen is also the heaviest part of 6:1 in a hydrolox propellant, so even extracting oxygen might kickstart the process. Methalox is interesting because the amount of hydrogen needed is reduced, replaced by Carbon, CH4, and COx is also found in the lunar ice.
  15. Best path to lunar provenance propellant?

    Extracting Oxygen from lunar dust (regolith) is possible. I was assuming that we will have confirmed accessible water in the deep craters of the (south) pole, making water, air and some other gases available on the moon. Here is a pretty good paper on extracting lunar water for propellant. It's a 16 year plan. Interesting to note, this 2010 paper pegs launch cost at $5m/t. OK, it's not my understanding, but I'm happy to use $1.4m/t as a baseline. With competition, prices may drop further. Putting propellant directly into LEO costs a certain amount. Presumably, it is cheaper to send propellant from the moon, because delta-v is much lower. So the question was, how soon and how would this be accomplished? Another way to look at it is, instead of building another space station (Deep Space Gateway) in low lunar orbit, it might be better to build a moon base so that water, oxygen, etc. don't need to be sent from earth to it and at a later time, propellant can ALSO be returned to LEO reducing the cost of sending people and cargo to the Moon and Mars. So, what's the fastest way to get this chicken-egg thing going?