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Crew Dragon Docks with ISS

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Re: Crew Dragon Docks with ISS

#211

Post by redis_mlc »

jes wrote: post #122
pfdietz wrote: post #114

Earlier quoted context omitted.

Guidance systems are vastly less expensive now, and can take advantage of things like MEMs, fiber laser gyros, and GPS (and, of course, modern computing power). The tanks on Falcon are welded using Friction Stir Welding, which was invented in the early 1990s. The landing algorithm for the first stage uses convex optimization algorithms based on interior point methods, which were not available in the 1960s. However, s…

I had not heard of Friction Stir Welding previously. Video that demonstrates the technique is here: https://www.youtube.com/watch?v=aNbQH8XBgxQ

The gimmick that Eclipse Aircraft (Paul Allen) used to get almost half a billion in investment is they would use FSW instead of rivets.

But that wasn't the main problem with creating a new jet, which has a myriad of other issues before certification.

Re: Crew Dragon Docks with ISS

#212

Post by pfdietz »

yellowapple wrote: post #81
toyg wrote: post #53

Earlier quoted context omitted.

I love space exploration like the next guy, but I have a massive fear that a proliferation of space-stations will lead to unpleasant situations. With all its tensions, the ISS has been an amazing tool for soft diplomacy; if we start having country-specific stations we’ll soon end up with nasty arguments. Already we have competing satellites rumoured to have classified capabilities, I hate to think what they could do…

My hope would be that all (or at least most) such new space stations would be "international" space stations. Stations should be differentiated by purpose rather than nationality, I think. Space doesn't have borders. But yeah, this is definitely a reason why I hope we can keep the ISS going and just keep building on it. Additional space stations should be for good reason (for example: orbiting the moon, or - my crazy…

I wonder if the 3rd Amendment would prevent nationalization of US space stations.

Re: Crew Dragon Docks with ISS

#213

Post by hinkley »

loufe wrote: post #74
hinkley wrote: post #36

I recall Elon was hoping to get an order of magnitude reduction in cost per launch, but Wikipedia claims it costs $160 million per launch versus the Soyuz price of $76 million per astronaut. That would “only” be a 3x reduction with a crew of seven, but they’ve configured for a crew of four, which is a hair under 2x. I wonder how reuse affects the math, and what they’ll be able to do to lower those prices further. Obv…

I would be interested to see the quote. Was he hoping for a 10-fold drop right off the bat for the first mission or rather for that drop "à un moment donné". I imagine the costs will continue to go down with time for the base model as things become more reusable, R&D costs drop, and more business comes their way.

If memory serves, that 10x isn't even really his number, but one borrowed from the enthusiast community. So not only was that number aspirational, but it was also a nod to a bunch of people who are essentially all talk and no action.

Also I found that if you fly on a refurb unit you get a 30% reduction in price, so a budget flier is looking at a 3x improvement in cost, which is quite a lot closer to the goal multiple.

If those numbers are profitable for SpaceX, and not fiction, then hopefully they have enough revenue to fund iterations that improve on what they already have.

Re: Crew Dragon Docks with ISS

#214

Post by redis_mlc »

yellowapple wrote: post #44
bane wrote: post #15

SpaceX runs basically as a giant R&D program that also happens to accomplish useful things as byproducts of its approach (with the miracle of insurance to cover costs if things get explody). Every flight is data for incremental improvement. If you think of all SpaceX has ever done was try to get to this point, with somewhere around 80 flights on the Falcon 9, but for a variety of mission buyers (NASA, USAF, Commercia…

> We now have the capability to put up another ISS today, resupply it, and staff it, at a fraction of the cost, all with launch equipment made by a single company that started a decade ago. This is the part that's exciting for me. Whether it comes in the form of more space stations like the ISS or a much bigger and reinvigorated ISS, either way is a vital step in the right direction toward making humanity less behold…

Almost no science is done on the ISS. Most of the time, energy and money spent on the ISS is to just keep the people alive.

But HN is consistent in admiring rocket launches without considering how pointless they are.

Bread and circuses. Nothing's changed since the gladiator days, have they?

Re: Crew Dragon Docks with ISS

#215

Post by geomark »

LanceH wrote: post #138
pfdietz wrote: post #114

Earlier quoted context omitted.

Guidance systems are vastly less expensive now, and can take advantage of things like MEMs, fiber laser gyros, and GPS (and, of course, modern computing power). The tanks on Falcon are welded using Friction Stir Welding, which was invented in the early 1990s. The landing algorithm for the first stage uses convex optimization algorithms based on interior point methods, which were not available in the 1960s. However, s…

I'm going to go with SpaceX doesn't have to source from 50 states. It also hasn't had its funding turned off and on.

"It also hasn't had its funding turned off and on."

That one's a killer. I was once a project manager at an aerospace company developing a new processor chipset for space applications. Our government customer would run out of money near the end of every fiscal year, forcing us to shut down. Then a few months later they would secure funds and ask us to restart. By then most of my staff would have been reassigned to other projects. It was stupidly inefficient and caused costs to balloon.

Re: Crew Dragon Docks with ISS

#216

Post by Geee »

JoeAltmaier wrote: post #47

What's with the gradient shadow? The space station shadow crossed the module, and it was blurry. I thought shadows in space were knife-sharp. The nose-cone shadow was. Its not the stream resolution, is it? Other knife-sharp features were visible. Maybe the space station is fuzzy? Maybe the module material blurs shadows? What am I missing?

Light from the sun -> sharp shadows. Light from Earth -> blurry shadows.

That's because the sun is almost a 'point' light source because it's far away, and Earth is 'area' light source because it's close by. Also it depends how far the shadow source is from the shadow target.

Re: Crew Dragon Docks with ISS

#218

Post by Geee »

hinkley wrote: post #36

I recall Elon was hoping to get an order of magnitude reduction in cost per launch, but Wikipedia claims it costs $160 million per launch versus the Soyuz price of $76 million per astronaut. That would “only” be a 3x reduction with a crew of seven, but they’ve configured for a crew of four, which is a hair under 2x. I wonder how reuse affects the math, and what they’ll be able to do to lower those prices further. Obv…

That's the cost for NASA. It's the price that SpaceX charges.

There's a massive margin on that price, which allows them to fund their other developments such as the Starlink and Starship.

Re: Crew Dragon Docks with ISS

#219

Post by yellowapple »

pfdietz wrote: post #212
yellowapple wrote: post #81

Earlier quoted context omitted.

My hope would be that all (or at least most) such new space stations would be "international" space stations. Stations should be differentiated by purpose rather than nationality, I think. Space doesn't have borders. But yeah, this is definitely a reason why I hope we can keep the ISS going and just keep building on it. Additional space stations should be for good reason (for example: orbiting the moon, or - my crazy…

I wonder if the 3rd Amendment would prevent nationalization of US space stations.

I guess it depends on who owns it, and whether or not it counts as a private home (and to be clear, nationalization in and of itself wouldn't run afoul of it, since the amendment is limited in scope to quartering of troops in a private residence without the actual residents' consent). It'd get even fuzzier if different people "own" different modules (so the military could perhaps occupy some shared corridors, but if people have attached their own modules as homes, then those would be off-limits for quartering).

Realistically, maritime law might be a better reference, given that space stations and other spaceships are informally (if not formally) referred to as "ships".

Re: Crew Dragon Docks with ISS

#220

Post by tdy721 »

olex wrote: post #127
danpalmer wrote: post #121

Earlier quoted context omitted.

Worth noting that Dragon also carries tons of cargo, whereas the Soyuz “sticker price” is for just a seat.

NASA has also so far insisted on only flying on new (unflown) boosters and only using freshly built Crew Dragon capsules. Both of those are able to refly multiple times, reducing costs further, once their reliability is sufficiently proven for NASA certification standards.

The agreed to reuse human capsules for cargo missions. No people at all.
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