RealKerbal3x 5,513 Posted January 4 Share Posted January 4 6 hours ago, mikegarrison said: Well, we'll see if it works. But to me the whole thing is starting to sound like they are getting desperate about figuring out their landing gear issues. Their issues have always been with Starship landing gear. Super Heavy landing gear has always been fairly straightforward, just stick some big fixed ones on there. This is more about undesigning those legs and moving the shock absorbers out of the booster itself to save mass. Quote Link to post Share on other sites
Deddly 5,022 Posted January 4 Share Posted January 4 7 hours ago, mikegarrison said: Well, we'll see if it works. But to me the whole thing is starting to sound like they are getting desperate about figuring out their landing gear issues. I suppose another concern is that he wants this to be a land/refuel/refly thing, and moving the booster from a landing spot to a launch pad puts a cramp in that. However, the precision required to come down and land exactly where they took off from is pretty crazy. I mean, even a small wind gust could cause a major disaster. I imagine the catching mechanism will work on the same principle as Mark Rober's "bullseye every time" dart board. Quote Link to post Share on other sites
magnemoe 2,630 Posted January 4 Share Posted January 4 19 minutes ago, RealKerbal3x said: Their issues have always been with Starship landing gear. Super Heavy landing gear has always been fairly straightforward, just stick some big fixed ones on there. This is more about undesigning those legs and moving the shock absorbers out of the booster itself to save mass. This, saving weight but also reducing reuse time. I think this is a bit over focused as you could just have more superheavy in the pipeline. You would want two as an minimum is case one can not be used but need servicing or worse is lost you are stuck if you only has one but with two your launch rate goes down. Quote Link to post Share on other sites
sevenperforce 7,226 Posted January 4 Share Posted January 4 15 hours ago, mikegarrison said: I suppose another concern is that he wants this to be a land/refuel/refly thing, and moving the booster from a landing spot to a launch pad puts a cramp in that. However, the precision required to come down and land exactly where they took off from is pretty crazy. I mean, even a small wind gust could cause a major disaster. I doubt it. Superheavy is basically a bigger Saturn V. You would need extremely strong winds to have any significant effect. Plus, it will have hot-gas thrusters at both the top and bottom (rather than only the top like the Falcon 9 first stage) for fine translation. Actually I can calculate that, come to think of it. Let's say that worse-case scenario you only have two of the ten-tonne RCS thrusters firing continuously, one at the top and one at the bottom. That's 20 tonnes of thrust or 196 kN. What kind of wind can that compensate for? The drag equation says that Fd = Cd*ρ*v2*A/2. So we set Fd = 196 kN and solve for v to find the maximum windspeed that two hot-gas thrusters can compensate for. Solving for v, we get v = sqrt(2*F/(Cd*ρ*A)). The drag coefficient of a cylinder perpendicular to an airflow is approximately 1. Superheavy will have a cross-sectional area of 9 m * 72 m = 648 m2. The density of dry air at sea level is 1.225 kg/m3. Plug and chug and you get v = 22.2 m/s or about 50 mph for us Americans. So unless Superheavy is planning on landing during a severe thunderstorm then it should be just fine. Quote Link to post Share on other sites
RealKerbal3x 5,513 Posted January 4 Share Posted January 4 17 minutes ago, sevenperforce said: Plus, it will have hot-gas thrusters at both the top and bottom (rather than only the top like the Falcon 9 first stage) for fine translation. Do we know that for sure, or are you just speculating? Quote Link to post Share on other sites
sevenperforce 7,226 Posted January 4 Share Posted January 4 If they do actually end up doing this I would expect the "catch" mechanism to also be the stabilizing member during Starship loading, similar to the function of the clasper arms on the F9 transporter-erector: The arms would hold onto the extended grid fins while the Starship is mated and loaded. At T-1 min, they would fold away and the grid fins would fold down for launch. At landing, the arms would remain open as Superheavy initially approached, then come together quickly to catch the grid fins. Once caught, they would lower the booster on the launch clamps and remain attached for stability until the next launch. 4 minutes ago, RealKerbal3x said: Do we know that for sure, or are you just speculating? I am about 95% confident that Elon specifically said the booster would have aft and forward hot-gas thrusters for fine translation control back when he was talking about landing on the launch clamps. Quote Link to post Share on other sites
magnemoe 2,630 Posted January 4 Share Posted January 4 14 hours ago, Deddly said: I imagine the catching mechanism will work on the same principle as Mark Rober's "bullseye every time" dart board. Yes, now scale it up a bit so the dart is 200 ton Thinking about it using rocket engines to move it around makes sense. Quote Link to post Share on other sites
Flavio hc16 339 Posted January 4 Share Posted January 4 2 hours ago, RCgothic said: tldr: 1)they have some contracts were they can choose between using falcon 9 and starship 2) She is positive about Starship reaching orbit in 2021 3) selling flight proven booster is easier than new ones 4) the sn8 has "de-risked" starship Quote Link to post Share on other sites
RCgothic 2,001 Posted January 5 Share Posted January 5 SN8 has been fully scrapped: Quote Link to post Share on other sites
RealKerbal3x 5,513 Posted January 5 Share Posted January 5 This is interesting: Quote Link to post Share on other sites
CatastrophicFailure 16,724 Posted January 5 Share Posted January 5 3 minutes ago, RealKerbal3x said: This is interesting: Interesting indeed. Now weld 4 of those panels to a skeletal sub-structure, and there’s your cargo bay doors... Quote Link to post Share on other sites
cubinator 8,501 Posted January 5 Share Posted January 5 Fewer welds means fewer potential points of failure...and fewer parts! Quote Link to post Share on other sites
Clamp-o-Tron 949 Posted January 5 Share Posted January 5 2 minutes ago, cubinator said: Fewer welds means fewer potential points of failure...and fewer parts! The framerate gets pretty bad in LEO, so they're taking steps to reduce the number of objects the universe has to run physics simulations for. Quote Link to post Share on other sites
cubinator 8,501 Posted January 5 Share Posted January 5 7 minutes ago, Clamp-o-Tron said: The framerate gets pretty bad in LEO, so they're taking steps to reduce the number of objects the universe has to run physics simulations for. It's all the pretty visuals they've got, have you seen those high-res pictures from orbit? If they ditched the fancy clouds and scattering they could launch much more complex ships. Quote Link to post Share on other sites
Clamp-o-Tron 949 Posted January 5 Share Posted January 5 (edited) 1 universe restart later... Edited January 5 by Clamp-o-Tron Quote Link to post Share on other sites
Spaceman.Spiff 621 Posted January 5 Share Posted January 5 Where'd you get that? Did you make it? Quote Link to post Share on other sites
Clamp-o-Tron 949 Posted January 5 Share Posted January 5 No, it's someone's Orbiter 2016 mod. https://www.orbithangar.com/showAddon.php?id=d12991b8-6daa-4541-a338-98c8d04f4655 Quote Link to post Share on other sites
Spaceman.Spiff 621 Posted January 5 Share Posted January 5 Cool. Cool, cool, cool. Quote Link to post Share on other sites
RealKerbal3x 5,513 Posted January 5 Share Posted January 5 TFR for flight! https://tfr.faa.gov/save_pages/detail_1_1073.html Quote Link to post Share on other sites
RCgothic 2,001 Posted January 5 Share Posted January 5 To unlimited altitude! :-O Quote Link to post Share on other sites
RealKerbal3x 5,513 Posted January 5 Share Posted January 5 1 minute ago, RCgothic said: To unlimited altitude! :-O SN8's TFR was unlimited altitude as well. It doesn't necessarily mean SN9 is going to go any higher. Quote Link to post Share on other sites
RCgothic 2,001 Posted January 5 Share Posted January 5 4 minutes ago, RealKerbal3x said: SN8's TFR was unlimited altitude as well. It doesn't necessarily mean SN9 is going to go any higher. Yeah, I got ahead of myself. Quote Link to post Share on other sites
cubinator 8,501 Posted January 5 Share Posted January 5 If SN9 is intact after the 12.5 km flight, they should do a 100 km flight with it. Quote Link to post Share on other sites
RealKerbal3x 5,513 Posted January 5 Share Posted January 5 Just now, cubinator said: If SN9 is intact after the 12.5 km flight, they should do a 100 km flight with it. I doubt they'll reuse any Starships until they've stopped rapidly iterating on it. By the time a prototype flies, it's already been made obsolete by the next one. Seeing SN10 do a 100km flight would be awesome though. Quote Link to post Share on other sites
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