151–160 of 342 posts
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I'm surprised the guy being a youtuber. He is the codecs guy at Apple Computers
Isn't he an astronomer / astrophysicist? You must be talking about another Scott Manley.
380s for ISP for the Raptor vacuum engine seems durn good, considering the tradeoffs between hydrogen and methane. The most efficient engines we've flown, the RL-10 [0] (used on the Delta IV and Atlas rockets as part of the Centaur Upper Stage) and the RS-25 [1], (the Space Shuttle Main Engine) get around 450-460s for their specific impulse. These engines use liquid hydrogen and liquid oxygen. The issue with liquid h…
Methane, which is cryogenic and less dense, ought to deliver more? Otherwise bigger tanks and operational issues will eat out the benefits.
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> Imo Elon is starting to get into contention for greatest engineer of all time. I don't know man, did he design it himself?
Meta-engineer? Engineering executive? At least he's trying to advance humanity instead of squandering it all on yachts like almost all the rest of the world's billionaires.
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It's the dawn of the true space age. And though Musk isn't a fan, this could even make solar power satellites economical. The monolithic designs from the 1970s would be absurdly expensive, but modern designs like SPS-Alpha get economies of scale by using lots of small identical parts that self-assemble in orbit. According to the book The Case for Space Solar Power , a 2GW satellite would deliver electricity at 15 cen…
Geostationary orbit is further away than the most distant part of the Earth. If you have a way to transmit power efficiently over that distance, it’s still going to be cheaper to put the panels on the ground in Nevada, the Sahara, Saudi Arabia, the Gobi, and Australia, and transmit the power from there. (Microwave towers, LEO satellite relays, superconducting wire, whatever). It’s likely to be really hard to make it…
Why people don't have to trust us: because the technology isn't physically capable of maintaining even that low energy density at the target, without the reference signal from the ground.
Why put the PV in space instead of on the ground: because there's 5.4X as much energy available and it's 24/7.
There's real engineering behind this design, detailed in the book and the SPS-Alpha final report to NASA: https://www.nasa.gov/pdf/716070main_Mankins_2011_PhI_SPS_Alp...
I'm not aware of any real engineering studies for things like transmitting power via LEO satellite relays from the Sahara. Personally I don't find it plausible, but if you can provide such a study I'm willing to change my mind.
380s for ISP for the Raptor vacuum engine seems durn good, considering the tradeoffs between hydrogen and methane. The most efficient engines we've flown, the RL-10 [0] (used on the Delta IV and Atlas rockets as part of the Centaur Upper Stage) and the RS-25 [1], (the Space Shuttle Main Engine) get around 450-460s for their specific impulse. These engines use liquid hydrogen and liquid oxygen. The issue with liquid h…
I just want to point out that SpaceX has not yet successfully put a human in LEO. The moon seems well beyond their technical capabilites at the moment and Mars seems like a fools dream at this point in time.
5 years ago, you could have said the same about SpaceX and reusable rockets, and look where they are now.
That was a very dense an informative presentation last night, but I think the main take away is that rapid reusability is a game changer. In fact, game-changer is probably an understatement, basically every intuition and rule-of-thumb we have about space launches and travel will have to be rethought. And this will be true even of SpaceX falls well short of meeting their stated targets (2020 orbit, 150t capability, mu…
"the world's launch capacity will be expanded by two orders of magnitude" How will so many more launches impact the space junk problem? From what I understand, there's already a catastrophe waiting to happen if some space junk collides with a satellite and causes a chain reaction of more space junk destroying more satellites, etc... until there's an impenetrable debris field around the earth. Will having that many mo…
I just want to point out that SpaceX has not yet successfully put a human in LEO. The moon seems well beyond their technical capabilites at the moment and Mars seems like a fools dream at this point in time.
I am so amazed by the genius of making it out of steel. It's just so completely counter intuitive but has accelerated their progress so much. If they told you the stats of the material, better strength at cryo tempertures meaning mass reduction, higher melting point meaning minimal heat shielding and great thermal conductivity it would be easy to imagine it was some new super composite. Then your head explodes when t…
I know there are 1000 of them 100x smarter than me at all of this, but I have my doubts that the specs for "cold rolled" stainless will hold up after tens of re-entries, as it is effectively being tempered over and over.
Although its a curious topic, I would have no doubt that whatever temperature cycling they design parts of the structure to go through in their "rapidly reusable" regime, the effects of "heat fatigue" or whatever to call it will have been rigorously assessed .
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FH was 5 years+ behind schedule before it was built and launched. Starship already has multiple constructions going on, with multiple prototypes to test and multiple full-size vehicles planned quickly. In 2011, FH was supposed to have "arrival at launch site" by 2H 2012. It first launched in 2018 (after arriving at launch site in 2018 not 2012). The same level of delay would mean the first Starship does not reach orb…
FH got delayed because they kept improving the F9, so they didn't need the FH for many of the original target payloads. Some of the delay was due to technical issues, but changes to the F9 were significant over that time period. Starship has no dependencies on the Falcon stack.