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SpaceX Crew Dragon Splashes Down After Historic Test Flight

scientificamerican.com

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Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#131

Post by nickik »

ChuckMcM wrote: post #9
Tuna-Fish wrote: post #7

Earlier quoted context omitted.

They are unlikely to do this at this point. The big problem is that while the capsule will be reusable, since NASA killed the propulsive landing for Dragon 2, it now needs to splash down in saltwater and therefore is not considered safe for humans after the first use. This makes Dragon 2:s too expensive for large-scale space tourism. Unless there is suddenly a huge market for this, I think SpaceX would prefer to sell…

I'm not disagreeing with the idea that Musk would shoot for using Starship for tourism, but I also think that I wouldn't put it past SpaceX to continue toward qualifying a reusable Dragon 2. They are already getting good experience (and can experiment with) Dragon Cargo capsule re-use to better understand the impact of salt water landings on their designs. And while it would be hard to find space for the landing stru…

> continue toward qualifying a reusable Dragon 2.

Pretty unlikely. To have it landing on land would be incredibly difficult specially to qualify.

Also they already have Starship and Starlink as huge projects they have to finance. They will make as much money as possible of Dragon 2 with the flights from NASA and invest that money in Starship.

Starship could actually be useful for tourism.

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#132

Post by skellington »

sourkremlin wrote: post #18
Tuna-Fish wrote: post #7

Earlier quoted context omitted.

They are unlikely to do this at this point. The big problem is that while the capsule will be reusable, since NASA killed the propulsive landing for Dragon 2, it now needs to splash down in saltwater and therefore is not considered safe for humans after the first use. This makes Dragon 2:s too expensive for large-scale space tourism. Unless there is suddenly a huge market for this, I think SpaceX would prefer to sell…

where did you hear that dragon 2 is not safe for humans after splashdown? that's not accurate

You know, it's like how once you put a boat into water once, it's unsafe for humans...

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#133

Post by hermitdev »

nordsieck wrote: post #47
slg wrote: post #16

Earlier quoted context omitted.

I am curious about this as well. Was the propulsion the problem? Did they just want a water landing? Did they specifically want an ocean landing to increase the acceptable margin for error in the splash down location? Is there some specific property to the salt water like buoyancy that is important? Would a landing in fresh water like the Great Lakes (or Lake Victoria if they need something more equatorial) meet NASA…

> Would a landing in fresh water like the Great Lakes (or Lake Victoria if they need something more equatorial) meet NASA's requirements and allow the capsule to be reusable? I'd guess that one of the big reasons they (and everyone else who does water landings) lands in the ocean, is that it is much more palatable to regulators to create an exclusion zone in the ocean, which people can easily route around. Also, peop…

I'd also wager that the concentration of vessels on the great lakes is significantly higher than 100 miles or so out into an ocean. Wouldn't want to land on a sailboat. Don't think that'd work out well for either end.

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#134

Post by sandworm101 »

simonh wrote: post #66
sandworm101 wrote: post #12

Earlier quoted context omitted.

SpaceX is breaking new ground, but it isn't the first corporation to launch large rockets. The Saturn 5 wasn't built by the air force, nor was shuttle constructed by Nasa. These objects were built by contractors, corporations working under government contracts. The differences between SpaceX today and the corporations that built, and largely launched, the big rockets of the past is largely a legal distinction. Space…

The big rockets of the past were in very large part designed by NASA. The contractors did have a lot of input, but NASA drew up the detailed specifications and had the final say on every aspect of the design and engineering. Different components often had different manufacturers. For example each of the three stages of the Saturn 5 had a different manufacturer and all three were designed by NASA. The first stage was…

Final specs on paper came from nasa, but only after much back and forth with industry. The fact that any engineer is paid by nasa or a private company is, as i stated, a simple legal distinction rather than a revolution.

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#135

Post by thachmai »

simonh wrote: post #60
perilunar wrote: post #51

Earlier quoted context omitted.

I wonder if they could catch the Crew Dragon with Mr Steven instead of water splashdown? No loss if they miss, and less refurb if they succeed.

Mr Steven is designed to catch fairing halves which weigh just under a metric ton. A Dragon capsule weighs 9.5 tons and can carry up to 7 people or 3 tonnes of return cargo, so it’s from 10 to 13 times heavier than a fairing half.

Metric ton sounds redundant to me. Does the US have the notion of a "imperial ton"? (1000lbs?)

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#136

Post by grzm »

thachmai wrote: post #135
simonh wrote: post #60

Earlier quoted context omitted.

Mr Steven is designed to catch fairing halves which weigh just under a metric ton. A Dragon capsule weighs 9.5 tons and can carry up to 7 people or 3 tonnes of return cargo, so it’s from 10 to 13 times heavier than a fairing half.

Metric ton sounds redundant to me. Does the US have the notion of a "imperial ton"? (1000lbs?)

Yes, tons do differ. A metric ton (or tonne) is 1000kg. In the US what’s commonly referred to as a ton is a short ton, or 2000 lbs.

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#137

Post by NeedMoreTea »

thachmai wrote: post #135
simonh wrote: post #60

Earlier quoted context omitted.

Mr Steven is designed to catch fairing halves which weigh just under a metric ton. A Dragon capsule weighs 9.5 tons and can carry up to 7 people or 3 tonnes of return cargo, so it’s from 10 to 13 times heavier than a fairing half.

Metric ton sounds redundant to me. Does the US have the notion of a "imperial ton"? (1000lbs?)

An imperial ton would be the British one, also known as a long ton. It's 2,240 lbs, which is slightly heavier than a metric tonne.

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#138

Post by Faark »

zaroth wrote: post #99
grey-area wrote: post #97

Earlier quoted context omitted.

They thought about it, but no, the ultimate long term plan is that huge shining steel starships will take off and land on the same pad carrying lots more people or cargo. Some things are easier when you’re bigger.

Apparently the SuperDracos have the necessary thrust and fuel to bring Dragon to a stop from terminal velocity, Dragon just lacks the landing gear. So then why not use that to slow down just before a splash down? Perhaps if you throttle them down to the point where the G-force is reasonable, the losses to gravity add up too quickly and you run out of thrust. Too bad :-(

The primary reasons they don't do this are likely economic, but the hypergolic fuel used by SuperDracos also isn't particularly healthy [0].

[0] https://www.reddit.com/r/spacex/comments/29qwj9/how_toxic_wi...

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#139

Post by computerex »

jryle70 wrote: post #119
computerex wrote: post #77

Earlier quoted context omitted.

I think you are getting ahead of yourselves. For one thing, SpaceX is a launch provider. Whether there is even demand for Mars launches remains to be seen. I think SpaceX itself has said that it can't/won't be funding the Mars launches. And secondly, this was an unmanned test launch to LEO. I think it'd be more prudent to wait till we get reliable manned launches to LEO before dreaming about other planets. It's very…

> I think SpaceX itself has said that it can't/won't be funding the Mars launches. What they said was they couldn't be funding the whole Mar endeavor. They certainly can and plan to fund Mars launches. They stated their aspirational goal of sending the first unmanned spaceship to Mar in 2022, followed 2 years later with a manned one. They have seemed to pivot a bit to Moon, so I'm not so sure what their current plan…

> but a trip to Mar isn't out of their reach financially.

Source? I highly doubt this is accurate.

Re: SpaceX Crew Dragon Splashes Down After Historic Test Flight

#140

Post by 8bitsrule »

Goin a little 'get off my lawn' : what's the big deal here? What's it leading to? Where is it taking us? What's the return on all of the investment (except further enriching a few of the right pockets)?

We aren't going to the stars. We're not colonizing space. Do we need to mine resources off-planet because we waste so many resources on-planet? Our robotic solar system explorers don't really need any help.

OTOH, we are destroying the spaceship we were born on, with so many indifferent tactics that it sometimes almost seems planned. Other, helpless species are disappearing regularly. So I find it hard to feel celebratory about these minor victories on the way to ... ???

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