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SpaceX Dragon successfully docks with International Space Station

arstechnica.com

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Re: SpaceX Dragon successfully docks with International Space Station

#31

Earlier quoted context omitted.

The $132/g vs $127/g price would make sense, all other things being equal (which are not, ok), if SpaceX were pricing in a duopoly, right?

If I take your meaning correctly, yes. For SpaceX the actual costs they experience are quite low compared to their competition. For example, they don't use rad-hardened CPUs, nor do they use vxworks. This alone saves them millions of dollars. However, it makes sense for them to offer their services as close to the competition's prices as possible, because it maximizes their profits. You see the same thing on their la…

Dragon uses vxworks: http://www.spacex.com/downloads/dragonlab-datasheet.pdf second page, under Flight Software

Re: SpaceX Dragon successfully docks with International Space Station

#32
post #31

Earlier quoted context omitted.

If I take your meaning correctly, yes. For SpaceX the actual costs they experience are quite low compared to their competition. For example, they don't use rad-hardened CPUs, nor do they use vxworks. This alone saves them millions of dollars. However, it makes sense for them to offer their services as close to the competition's prices as possible, because it maximizes their profits. You see the same thing on their la…

Dragon uses vxworks: http://www.spacex.com/downloads/dragonlab-datasheet.pdf second page, under Flight Software

Thanks for the correction, that's interesting. It's a testament to the utility of vxworks, I suppose, which costs a few hundred thousand dollars per client. Even so, not using rad-hardened CPUs still saves them millions, especially when you factor in backup hardware, test units, etc.

Re: SpaceX Dragon successfully docks with International Space Station

#33
post #24

Earlier quoted context omitted.

The capsule's thrusters had a blockage which prevented them from maneuvering and deploying the solar panels. They managed to clear the blockage just fine.

Interesting. Did they release informations on how they solved that? Also, don't they have some built in redundancy for the thrusters?

3 of 4 thruster packs experienced the issue; they need 2 of 4 to open the solar panels and 3 of 4 to dock with the ISS. From what I understand they got all 4 working again using the "water hammer" effect to clear the blockage, but I'm not sure how accurate that is.

Re: SpaceX Dragon successfully docks with International Space Station

#34
post #21

Earlier quoted context omitted.

I remember my statistics lecturer was fond of pointing out that NASA estimated the probability of SOMETHING failing on launch was (1). That is, because of the complexity of the project, there was always something that was missed or broken - although it could have been as simple as a bulb that was backlighting a switch might be blown, or a cupboard might have been restocked incorrectly, or a calculation for external e…

They had a shuttle mission where everything was nominal, even the toilet kept working the whole mission. But yeah, space flight is like that. Then again its relatively rare for a jet fighter to consistently return Code 1, no faults. Usually its Code 2 with minor fixes required pretty regularly. Code 3 is an abort.

The human body is basically code 2 all the time. It's just that it can fix itself, until you get code 3.

Re: SpaceX Dragon successfully docks with International Space Station

#35
post #24

Earlier quoted context omitted.

The capsule's thrusters had a blockage which prevented them from maneuvering and deploying the solar panels. They managed to clear the blockage just fine.

Interesting. Did they release informations on how they solved that? Also, don't they have some built in redundancy for the thrusters?

I remember it being something about check valves in the oxidizer pressurization system. I don't recall where I read that, but it's probably not too hard to dig up (I'm just lazy).

Re: SpaceX Dragon successfully docks with International Space Station

#36
post #33
post #24

Earlier quoted context omitted.

Interesting. Did they release informations on how they solved that? Also, don't they have some built in redundancy for the thrusters?

3 of 4 thruster packs experienced the issue; they need 2 of 4 to open the solar panels and 3 of 4 to dock with the ISS. From what I understand they got all 4 working again using the "water hammer" effect to clear the blockage, but I'm not sure how accurate that is.

Imagine it's your job to fiddle around remotely with fuel pump electronics (or whatever may create that water hammer) within a time window of maybe 20 minutes or else you've just sunk a 100M investment somewhere in the ocean. Must be lots of fun o.O

Re: SpaceX Dragon successfully docks with International Space Station

#37
post #31

Earlier quoted context omitted.

Dragon uses vxworks: http://www.spacex.com/downloads/dragonlab-datasheet.pdf second page, under Flight Software

Thanks for the correction, that's interesting. It's a testament to the utility of vxworks, I suppose, which costs a few hundred thousand dollars per client. Even so, not using rad-hardened CPUs still saves them millions, especially when you factor in backup hardware, test units, etc.

It's probably because it is:

- Certified (for military use maybe?)

- It gets out of the way when needed

- Lots of people experienced in it

"Even so, not using rad-hardened CPUs still saves them millions"

Yes

Re: SpaceX Dragon successfully docks with International Space Station

#38
post #36
post #33

Earlier quoted context omitted.

3 of 4 thruster packs experienced the issue; they need 2 of 4 to open the solar panels and 3 of 4 to dock with the ISS. From what I understand they got all 4 working again using the "water hammer" effect to clear the blockage, but I'm not sure how accurate that is.

Imagine it's your job to fiddle around remotely with fuel pump electronics (or whatever may create that water hammer) within a time window of maybe 20 minutes or else you've just sunk a 100M investment somewhere in the ocean. Must be lots of fun o.O

There's plenty of excitement for me just tweaking a live production server, not sure my heart could cope with what you just described.

Re: SpaceX Dragon successfully docks with International Space Station

#39

Earlier quoted context omitted.

The $132/g vs $127/g price would make sense, all other things being equal (which are not, ok), if SpaceX were pricing in a duopoly, right?

If I take your meaning correctly, yes. For SpaceX the actual costs they experience are quite low compared to their competition. For example, they don't use rad-hardened CPUs, nor do they use vxworks. This alone saves them millions of dollars. However, it makes sense for them to offer their services as close to the competition's prices as possible, because it maximizes their profits. You see the same thing on their la…

> However, it makes sense for them to offer their services as close to the competition's prices as possible, because it maximizes their profits.

This is an important lesson that I learned the hard way with my first startup.

Not only does it maximize their profit, but it also helps reduce the risk of setting off a price war. In my case, we went into the ISP industry in '95 with a price about 1/3 of the larger competition in Norway. What we did not realize - being completely fresh to business - was that these guys did not price their service that way because their costs were that high, but because the market at a time (which was not yet regular consumers) could bear it and their margins were high.

So when we and a couple of other small ISPs launched with so much lower prices in autumn of '95 it too two days, and the big incumbent ISPs followed suit, and eventually pushed the prices much further down. We stuck it out a year before we sold our dial up customer base and focused on hosting and consulting when it was clear that the big providers at that point had seen that their big price drops were well timed for a big growth in the consumer segment and decided they were willing to sustain big losses to take market share.

It took several years before the market segment returned to profitability for anyone, and by then most of the small providers were out of the picture...

You really don't want to rock the boat too much if you can instead build up a war chest, unless you're extremely well funded and/or know for a fact that you can not only beat the competition on price, but can also survive if they decide taking losses for a while is worth it if they can get rid of you.

Re: SpaceX Dragon successfully docks with International Space Station

#40
post #4

Earlier quoted context omitted.

I'm sure there's a lot of information that could paint a more complete picture, but here's a start. According to NASA[1], a shuttle launch cost $450 million on average. Their contract with SpaceX covers 12 launches for $1.6 billion[2], or roughly $133 million per launch. SpaceX also received $75 million from NASA to develop a crewed version of the Dragon capsule. I'm sure NASA has made other payments to SpaceX over t…

If a shuttle launch and a Dragon launch have the same utility, what you say is true, but the shuttle can carry a lot more cargo. For example, the Dragon is nowhere near large enough to carry a full space station module. I'm not sure that this renders what you said false , but there's a lot more to it than this.

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