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    Mathematics, physics, science, futurism, spaceflight, science fiction

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  1. Actually, I was basing the 10 tons estimate on how much propellant I had once estimated would be left over in the FH upper stage if it only had to get a smaller payload mass to TMI. I then imagined doing a propulsive landing on Mars. But that’s really not the aerocapture method I was thinking of here. Perhaps someone could do a Kerbal Realism Overhaul of a Falcon Heavy upper stage propulsive landing on Mars. Robert Clark
  2. According to this article, NASA support for the mission was cancelled for political reasons: https://news.ycombinator.com/item?id=26274117 Robert Clark
  3. ‘Red Dragon’ can also do it launched atop the Falcon Heavy: 'Red Dragon' Mars Sample-Return Mission Could Launch by 2022 By Mike Wall September 10, 2015 https://www.space.com/30504-spacex-red-dragon-mars-sample-return.html It would use though both aerobraking and propulsive landing. This article claims ‘Red Dragon’ was cancelled only for political reasons: https://news.ycombinator.com/item?id=26274117 By the way, looking at that delta-v map again, it looks like for a fully aerocapture approach to landing at both Mars and Earth, you could get greater mass to Mars. I was considering a 10.2 km/s delta-v each way to Mars and back, but part of this is for propulsive burns when arriving at Mars, or returning to Earth. If you do a fully aerocapture descent, i.e., aerodynamic slow down, with parachutes when sufficiently slowed, then you just need to do a Trans Mars Injection burn and this only takes ca. 3.8 km/s. And the Falcon Heavy can launch 16.8 tons to Mars on this trajectory. This would then make a direct descent to the Mars surface. Note the higher mass means we could add additional aerodynamic surfaces to assist with the slowdown on arrival at Mars. Also, for return to Earth, if this is fully aerodynamic, the delta-v for this is only around 6.3 km/s. So a larger mass could be returned from the Mars to Earth. Robert Clark Part of the reason why Apollo was multi-billion. For instance for the current sample return plan they want the Mars Ascent Vehicle to rendezvous with an orbiting spacecraft and then be launched by a another stage to Earth. Far simpler and cheaper to launch directly from Mars surface towards Earth. Robert Clark
  4. NASA has collected its first Mars sample. But it needs $4 billion, 10 years, and new technology to bring the rock to Earth. https://www.businessinsider.in/science/news/nasa-has-collected-its-first-mars-sample-but-it-needs-4-billion-10-years-and-new-technology-to-bring-the-rock-to-earth-/articleshow/86051685.cms Take a look at the delta-v map above. It takes about 10.2 km/s total delta-v each way to go to and from Mars. The Falcon Heavy can get about 16.8 tons to Trans Mars Injection, where TMI is the propulsion step to head towards an encounter with Mars, that is, meet it in its orbit about the Sun. Then I estimate with a smaller 10 ton payload the Falcon Heavy’s upper stage could land a 10 ton payload on the surface of Mars by using aerocapture , which minimizes the propellant required to do the landing. This then allows a wide variety of combinations of existing solid rocket motors, 3 stages, such as from the Star series to make up the 10.2 km/s required delta-v to return from Mars. All these are existing elements so could be mounted, like, tomorrow, and at a few hundred million dollar cost. Robert Clark
  5. The latest estimates put the ice thickness in the range of 15km to 25km. While we have not had any need to drill through that much ice, that doesn’t mean its not possible or even technically difficult. Note that because of Europa’s much smaller gravity, the pressure beneath the ice would only be in the range of 200 bar, about the pressure on Earth below 2,000 meters. We have deep sea submersibles that can explore that deep on Earth. There have been a few proposals for drilling that deep on Europa: NASA's building a robot to explore Jupiter's moon Europa — from underneath its icy shell The buoyant robot will 'drive' upside down on the undersurface of Europa's ice CBC News · Posted: Feb 21, 2020 4:26 PM ET | Last Updated: February 21, 202 https://www.cbc.ca/radio/quirks/feb-22-live-animal-markets-and-viruses-largest-turtle-s-horned-shell-a-robot-for-europa-and-more-1.5470477/nasa-s-building-a-robot-to-explore-jupiter-s-moon-europa-from-underneath-its-icy-shell-1.5470495 https://youtu.be/qxU1VSSka4M ARCHIMEDES: Digging into the ice on Europa with lasers. https://www.universetoday.com/140499/archimedes-digging-into-the-ice-on-europa-with-lasers/ Robert Clark
  6. Thanks for that. I hadn’t known that. BTW, the reason why I think a lander mission could be more important than an orbiter mission is because I was assuming such a mission would tunnel though the ice to the subsurface ocean. This raises the possibility it could discover advanced life-forms, an Earth-shattering discovery. A lander mission that just stayed on the surface could find at most microbial life, and even that is doubtful considering the high radiation environment. The key question though: how to tunnel through kilometers of ice in a manner not requiring too much power or mass? Robert Clark
  7. What could you do with the addition to the FH of a hydrolox stage such as the 5-meter upper stage of the Delta IV Heavy at 27 ton propellant load or the Centaur V upper stage of the Vulcan Centaur at 54 ton propellant load? Actually the lander mission is so important, arguably more important than a Jovian-system orbiting mission, that at a ca. $150 million FH launch price it would be worth it for a lander mission to have its own dedicated FH launch. Robert Clark
  8. Thanks for that. This page estimates payloads possible of various launchers: http://www.silverbirdastronautics.com/cgi-bin/LVPcalc.pl The C3, i.e., hyperbolic excess velocity, of the flight to Jupiter is ~80 km2/s2. The calculator estimates the payload of the FH there as 5,000 kg with a possible maximum up to 6,400 kg. It might be NASA wanted more margin to be assured of success. Robert Clark Moon transfer? You mean landing on the Moon for a refueling? Robert Clark
  9. Thanks for that. I wrote to the author of the Youtube video showing a RSS Europa landing simulation. He said it was not a Delta IV Heavy launcher despite its triple-cored appearance. It was actually a much heavier vehicle of his own design. Robert Clark Actually the upper stage of the Delta IV Heavy would be even better at a propellant load of 27 tons, gross mass 30 tons. It’s described on the wiki page on the DCSS you linked to. Even better yet would be the Centaur V upper stage planned for ULA’s Vulcan Centaur. It’s to have a propellant load twice as large at 54 tons. Robert Clark
  10. Just looking at the Europa Clipper mission.  Do we know the mass of the orbiter after Jovian insertion?  Wiki suggests science instruments (82kg) and shielding (150kg).  Add propulsion and electrics (solar panels, batteries) and comms dish, etc.  At 5m high, 3m diameter  and 22m wide it is a big craft!

    1. Exoscientist


      I would think it would be the dry mass, which the wiki article gives as 2,600 kg.

      Of course for a lander mission it might not have the same mass.

        Robert Clark

  11. I found Kerbal RSS mission to Europa on Youtube, that gives a mass of the spacecraft including propellant as 9 tons launched by the Delta IV Heavy: Problem is I’m fairly sure the Delta IV Heavy could not launch that much mass to Jupiter with no gravity assists as shown in the video. It might be able to launch a much smaller mass, say, 2 tons. Robert Clark
  12. Let me modify it: any Real Solar System simulation of a Falcon Heavy launched flight to Europa would be very interesting to see, including just the orbital one planned and including ones using gravitational assists. By the way, another one of the suggestions for making a good challenge is doing one yourself first. At this point, I do need to start learning kerbal instead of just reading about it. Robert Clark
  13. Keep in mind the main market would be trans Pacific flights that now take a day to make. Making the flight to space could do it in 30 minutes. Robert Clark
  14. The Falcon Heavy has been awarded the Europa Clipper orbiter mission to Europa. It was calculated to take 6 years flight time using gravitational slingshots. However, actually it can be done in the same 3 years as by an SLS launch by using a high energy in-space stage such as the Centaur, no gravitational slingshots required. Moreover, it can even be a lander mission, not just orbital: Low cost Europa lander missions. http://exoscientist.blogspot.com/2015/02/low-cost-europa-lander-missions.html Robert Clark
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