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Hannu2

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  1. Yes, but control system handled it very well. Based on my experience (not related to rockets) it is much easier to do control which makes accurate position straight than control which can handle significant last minute errors without overshooting in any direction.
  2. No, they are not. But should they? Watching competition in space would feed people's competitive instincts just like watching sport do. If space companies had millions of fans like large sport teams maybe they could get significant boost to their funding by offering fan stuff, happenings, or even organized competitions to achieve some technical or scientific objectives. According to this source market size of sport business is almost 500 billion $. It is at least an order of magnitude larger than all space business and national organizations.
  3. Best mirrors reflects something around 99.999 %. They have also a limit how high field can be. There are many applications of highly reflective optical cavities but any practical energy storage is not possible.
  4. Probably yes. As far as I know planetary dynamos (sources of magnetic fields) are not very well understood. But it is believed that weak cosmic magnetic fields act as seed fields which start magnetic processes in rotating electrically connected liquids. When process is started field amplifies itself and increases many orders of magnitude and rotation of body gives energy. But it is complicated, field may be asymmetric, it changes during time, even change polarity etc. But it there probably is not such layer on Mars because otherwise it would generate magnetic field. Mars has cooled and mo
  5. It is not enough to keep B at surface constant. Magnetic field must be large enough that it can capture fast charged particles and steer them away from base. I do not know what is practical value in magnetic moment but in any case it is huge. All my numbers was several orders of magnitude larger than current production capability on Earth. And I do not believe that all other industries will be shut down to reserve all resources for mars base in next couple of thousands of years. Such a project would encounter very soon very hard resistance. Only some special materials have relat
  6. Your underestimate needed magnetic field by huge factor. We can calculate what we could do if Earth's magnetic field disappeared. Essential parameter is not field strength at the surface of the planet but magnetic dipole moment. Earth's magnetic dipole moment p = 7.95E22 A/m^2. Let's assume that we make huge coil on equator to create respective artificial field. Magnetic moment of planar coil is p = N*I*A, where N is number of turns, I is current and A is area of the coil. N*I is N*I = p / A = 7.95E22 A/m^2 / (pi * (6.37E6 m)^2) = 6.24E8 A. Critical current density of common sup
  7. If I discuss with farmers, they hate those satellites. They do not give farmers anything but authorities use the data against them, because they see easily what grows, where and how much. I live in Finland, where all farming depend on subsidiaries from EU and the state, but I think situation is quite similar in other EU countries. Maybe large farming companies can buy the data and use it for their benefit it but farmers with small family business know better local conditions in their small area and buying the useful data from satellite companies is too expensive.
  8. I know that everything must be entertaining. I just do not like it but I know that I am exceptional in that sense. I am very happy that my job is not to sell anything to anyone.
  9. I think the most important and interesting space technology are Flagship science missions. I can not say one over the others. But like Voyagers, Galileo, Cassini, Mars rovers, Hubble, sample return missions (manned and unmanned), New Horizons etc. Next very big thing for me is probably not Starship or Artemis but LISA, gravity wave detector in space. Of course other coming planet probes are too, for example that flying drone to Titan or Europa Clipper, if they will be realized. Manned operations seem to be more propaganda tricks than real scientific work. Yeah, it is nice to be able to vi
  10. You do not need to explain a special mechanism. Instead you should explain which part of your mechanism works against known physics and show it by observing such phenomenon. General natural law called as conservation of momentum tells that it is impossible to change momentum of closed system without interacting with environment. Actually conservation of momentum is a consequence of more fundamental natural law, a translation symmetry of space. It means that if natural laws are the same at every point in space. Also other well known conservation laws are connected to symmetry properties of
  11. It is return from intentional PR work. I think it is just fun for Musk to be popular among space nerds. Development process of Blue Origin seem to be very slow even Bezos has all benefits than Musk has and he is even richer. Musk's talks about Mars and aspirational schedules are what they are but SpaceX seem to bring every year something interesting to publicity or market.
  12. If these can be fired for ground tests they could probably do small hop with test device. But ULA does not test so intensively (or do not tell about their tests) and need more developed motors to their test devices.
  13. As far as I know humans can handle some level of overpressure long times if partial pressure of oxygen is corrected to about 0.2 bar. There seems to be nice temperature on Jupiter at about 5 bar level. I do not know how long it would be tolerable and there may also be toxic compounds at deep Jupiter's atmosphere so protective suit would probably be necessary.
  14. Overrating depends on source. Tesla was a great inventor and his inventions are well known. But there is some cult around him and I do not think that for example these three inventions was credible. Maybe he had some hypotheses or primitive ideas around these topics but not anything which could have been developed to work. Electromagnetism is extremely well known area of physics.
  15. Less damage to environment in case of anomaly, I think. Or it is just more fancy background in animation. That braking maneuver is crazy and impossible in real world. If they had not succeeded in another impossible task, landing and reusing first stage of orbital booster in economically feasible way, I would not believe.
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