kunok

Or dumping the prices so you get the a monopolistic position, or something similar, no is not the first time, Amazon is a good example of that. but that economical things are outside my engineering formation.

Look at the prices that are charged NASA and other USA institutions from SpaceX. I don't really trust SpaceX prices, Tesla for example is know from selling cars bellow the costs, and both are musk companies.

It will be a donation of course, in reality a 50% off is "the customer paid 50% of my reusability test" (numbers totally made up)

Don't forget that reusing launch stages add new fixed costs derived from the new installations and personnel required. It ain't the same process, is not that simple.

I think in the first ones there will be a huge discount, but after that SpaceX will offer you the launch services but wont allow you to choose a new or old rocket. If the customer want a new reliable rocket is in the added value sector. If for you SpaceX is cheap but not reliable enough you will choose another launch provider. Only if almost nobody wants to use used rockets then SpaceX will be forced to offer new or old ones, I don't think that will happen IF used stages are reliable enough which is still to be seen. And if the used rocket stages goes well, there is still to be seen what is done with the 400 engines/year factory. In the end I think the engines will be a lot more expensive.

SpaceX wants the cheap but reliable enough market. Not the added value market

https://www.reddit.com/r/spacex/comments/590wi9/i_am_elon_musk_ask_me_anything_about_becoming_a/d94tbej/ This was the first time I read it, but I think it wasn't the only one.

Only the carbon part, they explained the tank didn't had the internal insulator surface, and that means that they only have a big carbon manufacturing machine. Also means that the mass estimations of the tanks could be terribly wrong.

Like the biggest problem with all the plan was that the ITS doesn't have an accessible door. They only talked about the propulsion subsystem. I don't really think there is anything really done in any other subsystem. Releasing the ITS "specifications" is only a marketing move from SpaceX and/or for calming Musk's ego.

Could somebody slip in musk home/office whatever and put some hard modern scy-fy in his scy-fy collection? Because this is getting ridiculous.

@kerbiloid in my book that's good enough for a mars surface to orbit rocket. To solve the too high temp and too little isp, just add more O2 or even N2 , it will improve a little. I really think that most people oversimplifies the ice mining problem. Probably in that case better to filter out the co2 and use only the N2 , I already proposed that, in some thread. But lets put the nuclear out for a while. The idea for this is KISS and nuclear is problematic if you want for example a disposable stage.

Checking a table of adiabatic flame temp of rocket fuels there is C2N2 in between common fuels, so I was surprised. Researching both C2N2 and C4N2 are fuels with very high combustion temp and the better part, are made only from gases very common in the atmospheres both in Mars and Venus. Taking C4N2 , looks like it will be easy to produce, expensive in energy terms but relatively simple: With the atmospheric CO2 , O2 can be refined with the bosch or sabatier reactions with graphite as a byproduct (needs a close circuit with hydrogen though) According with the wiki https://en.wikipedia.org/wiki/Dicyanoacetylene C4N2 can be produced heating N2 available in the atmosphere and that graphite to 3000K (yeah I know high temps). This theoretical ISRU will give a highly energetic LO/C4N2 combo as rocket fuel, without the need of mining, only using atmospheric gases. It won't have good isp but the infrastructure will be simpler. What do you think? Any other only atmosphere ISRU option out there?

The insulation isn't designed for no direct sunshine, a surface can get very hot with sun radiation even in the lower W/m2 of mars. And insulation works both ways, a good insulation makes it difficult to cool an installation, humans and machines needs constant refrigeration that isn't in mars We already have gotten this conversation and you didn't listen to any argument. And insulation is an "easy" problem (just not like you oversimplifies) but thermal control systems won't be that easy. But still thermal problems are one of the easier problems in an hypothetic martian base. @Shpaget we didn't really have, probably it was north saying again and again that a antarctic base is a lot harder than martian base because it needs more insulation, like thermal control were a bigger problem than getting O2 or food or whatever... I don't recall what was the thread, but at least with me that was the discussion

I understand how the upper connector disconnect but I don't know how the lower one does, and I'm unable to find. The best explanation I found is this http://www.russianspaceweb.com/soyuz_lv_stage1.html in the right side, but it doesn't really explain how they are "severed", probably the best explanation out there is in perfect russian

Well at least some of them looks promising

@Hannu2 @todofwar I think I found something https://smartech.gatech.edu/bitstream/handle/1853/26452/147-242-1-PB.pdf Developments: -Durable metal SiC contacts at 500ºC (page 15) and package (Al2O3 encapsulate and gold contacs, page 17-19) -JFET SiC transistor (page 16) tested during 4000hours at 500ºC (page 21) being stable and with a huge current ratio between on and of states allowing logic. -And more complicated stuff like ¿wireless telemetry chips?, mems gas sensors, accelerometers, I'm sleepy, lazy and is not my field, seriously look And this is from 2008. There is more here https://sic.grc.nasa.gov/. I will research more another day

It's used in comercial sats for desaturating the reaction wheels. Is the only change in attitude really "free", so it's used every time possible.

I understand that the idea is that the band gap is bigger than the amplitude of the noise made by that effect, no? Some electronic engineer or solid state physic here?

It isn't because the high temp meltdown of silicon carbide, but for the higher band gap, allowing more "noise" if I understand correctly, probably at a cost of higher consumption. Example, (I have only read the abstract, I'm lazy today, I don't remember my original source) http://link.springer.com/referenceworkentry/10.1007%2F978-0-387-29185-7_24 It also cites the diamond as a high temp electronic material. And I know there is high temp effects on materials, but then we already have materials withstanding this kind of conditions, lots of superalloys usually work in worse conditions. We can deal with that using more security margin or whatever, that's a design problem.

You are basically getting dirt, or breaking rocks and getting ore, and after that opening a valve so the "balloon" gets filled with nitrogen and lifts to the skies where is a floating processing plant. I'm not really an expert of anything of that, but doesn't really seem too complicated to be done with a mechanical automat And anyway we as civilization, not for venus really but for industrial purposes, should develop silicon carbide based electronics that should withstand 600ºC, and maybe even bigger temp electronics (also not my field, maybe there are better options).

Bad quoting, I was pointing only to "the second will melt before inflate" @Steelyou don't, you use high temp equipment, maybe you cool down a little electronic control center, but that's all. 500ºC isn't that big

You can have a high temp metal balloon, the only needed is that the total density is lower than the atmospheric one, you can use as lifting gas nitrogen from the atmosphere. And for energy, in venus surface you go full nuclear, is the most logic way. You want a fuel with a huge energy density not fast disposing nonrenewable fuel.

Is easier than that, we can use radio for that, just use the whole earth as an antenna https://en.wikipedia.org/wiki/Extremely_low_frequency It was used in submarines, but the data rate is so low that was only useful to say them: go up to listen, we need to send you a message

What if I say that 92 bar and 490ºC aint that big? We have high temperature alloys, and pressure isn't really a problem, low pressure (for liquids, because sublimation) and differential pressure are and there is none in venus surface. Heck, superalloys inside rocket engines works in worse conditions. The problem is electronics, there is no hight temp electronics, it is theorized that silicon carbide based electronics could withstand 600ºC temps. So maybe we can develop that, but you are getting put out any develop. Fortunately we can do mechanical automats/computers, they are pretty old and basic, it just need lots of more mass. Other option is using liquid nitrogen/whatever to refrigerate a little control center inside the craft. Maybe other problem is energy generation, but we can deal with that generating even more temp, so a nuclear reactor or a pretty big RTG is workable. To improve my though I need a better definition of what are we talking about "mining". High concentrated ore? Diffuse in the dirt? How hard is it to do a mechanical automat that does that? Just graving X ton of dirt and bringing to a flying refinery is enough? The last one could be relatively easy

This will have a brutal aberration :| but I suppose you can do the corrections in the rest of the optical system.