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Crew Dragon Docks with ISS

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Re: Crew Dragon Docks with ISS

#121

Post by danpalmer »

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…

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

Re: Crew Dragon Docks with ISS

#122

Post by jes »

pfdietz wrote: post #114
7thaccount wrote: post #22

Earlier quoted context omitted.

Incredibly impressive, but you have to take into account both more modern technology, as well as the fact that they were able to build off the shoulders of giants. It is still amazing of course, but I doubt they could've done the same thing during the era of the mercury program, so not really apples to apples comparison.

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

Re: Crew Dragon Docks with ISS

#124

Post by plorg »

dnautics wrote: post #117
VLM wrote: post #89

Earlier quoted context omitted.

sensors and wiring always weighed more. Of course now the wiring COULD be CANbus or similar in concept instead of individual (heavy) wires. Or move the analog processing and microcontroller to the sensor itself instead of running wires all over the place to a central computer.

Iirc the computers are connected by commodity cat 6e Ethernet.

Do you mean ethernet as the link layer? I ask because I've encountered a number of systems where CAN bus is operated over a cat 6e physical layer.

Re: Crew Dragon Docks with ISS

#125

Post by anewdirection »

orisho wrote: post #37

They mentioned something about the suit pressure for one of them being lower than expected and asked them to check for "white teeth" on 3 zippers, which they reported seeing on all 3. Can anyone explain what that is?

If the suits are pressurized more than the environment, escaping gasses often cause moisture or frost to form at the point of escape due to differential cooling condenstion. Could that be what they were seeing?

Re: Crew Dragon Docks with ISS

#126

Post by tomp »

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’m guessing the current price has to pay for a whole new rocket, as NASA probably won’t use a used (“flight-proven”) one for humans.

Eventually I expect used ones to be not only cheaper, but also more reliable. Like for (water)ships - they say “it’s new after you’ve owned it for a year”, the implication being that you spend the first year discovering and fixing manufacturing defects.

Re: Crew Dragon Docks with ISS

#127

Post by olex »

danpalmer wrote: post #121
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…

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.

Re: Crew Dragon Docks with ISS

#128

Post by olex »

neals wrote: post #123
war1025 wrote: post #118

Earlier quoted context omitted.

Came here hoping to find an answer to this. It looked like it was bothering him quite a bit

Apparently, space is hard...

Station hatches sure as hell are. Looks like it happened during the hug session, while still mostly inside the hatch.

Re: Crew Dragon Docks with ISS

#129

Post by manquer »

crocal wrote: post #105
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…

Did it really cost only 5B$ to get there? I just ask because if confirmed it’s unbelievably cheap. I am /stunned/.

In direct investments perhaps yes, but like all things it is bit more complicated, it can be cheaper in each generation, you can leverage existing talent and their experience from before .

In theory a new entrant could achieve similar feats with lesser money . For example rocket lab is doing pretty well for their size with some real innovation based out of New Zealand! Extremely likely part of their staff would come from spacex ULA, NASA etc . Similarly spacex would have leveraged from ULA , NASA as well .

NASA also does help them in some areas as part of this program and others and also the money they (and others) have spent during the last 15 years especially without validation. Very few customers would invest in 10 year product development journey they way NASA has with CCS.

That would not possible without NASA’s own budgets being so large to support kind of projects like the shuttles and ISS in the first place . Only then the couple of billion they spent will look small enough to take that risk.

Re: Crew Dragon Docks with ISS

#130

Post by gfodor »

tnli wrote: post #29
godzillabrennus wrote: post #16

Earlier quoted context omitted.

Elon Musk will have cities on planets names after him for generations to come. The legacy he leaves will be greater than that of Ghengis Kahn, Ceasar, or Alexander the Great.

Elonville, Musktown?

I put like 90% liklihood we'll have a nation state named "Musk" on Mars in 50 years.
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