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Chronic...
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Homecoming today for a couple of astronauts.

Splashdown in less than an hour.

Splashdown? Hey, what happened to runways? Wink   ;)
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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quote:
Originally posted by Henry J:
I guess the next question is how many decades until they get a working version of the fusion rocket propulsion system that I've been reading about. Without that or something as good, interplanetary trips using chemical rockets would take years. I gather that with fusion rockets, a trip to Mars could be just a few months each way, with a month or two to sight-see while there.

Looks like they're expecting the fuel for this to be a mixture of H2 and He3. I don't know what the benefit of the He3 is for the process, especially if the stuff is rare on Earth. They're talking about mining the moon for it, where it's plentiful. (On Earth most He is He4 not 3.)

ETA: Ah so. H2 + H2 -> He3 + n has two problems: it requires a much higher activation temperature, and it emits a free neutron for every fusion reaction. H2 + He3 -> Li is easier to trigger, and this reaction itself doesn't emit a neutron. Of course, a few of the H2's hit other H2's, but it's a small percentage, partly due to the lower temp needed for H2 + He3.

It's interesting that He3 is rare on Earth but plentiful in other places. I gather it's what's produced in stars, and some of it gets blown out in the solar wind, which is why the moon has a lot of it (I guess Earth's magnetic field deflects it from here). I guess Earth's He4 supply comes mainly from radioactive decay.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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The articles I've read about fusion rockets talked about using them to reach planets furthur out from the sun than us.

But no mention that I've seen of reaching planets closer to the sun. Surely they're not ignoring them just because they're inhospitable? Sure, of them is a pressure cooker, and the other alternates between baking and freezing, but still.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Something occurs to me. For a trip to Mercury, if it uses the most economical flight plan, it would get there shortly before Mercury goes behind the sun from Earth. Plus, the return trip would need to start shortly after Mercury moves out from behind the sun as seen from Earth.

That sort of interferes with straight line communication; in order to have quarter hour communications they'd have to put a relay of some sort in an orbit visible to both Earth and Mercury. (I say quarter hour because it would take radio waves about that long to get from Earth to the far side of Mercury's orbit, even if they could.)
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
AAA+
Picture of ImPeach
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quote:
Originally posted by Henry J:
Something occurs to me. For a trip to Mercury, if it uses the most economical flight plan, it would get there shortly before Mercury goes behind the sun from Earth. Plus, the return trip would need to start shortly after Mercury moves out from behind the sun as seen from Earth.

That sort of interferes with straight line communication; in order to have quarter hour communications they'd have to put a relay of some sort in an orbit visible to both Earth and Mercury. (I say quarter hour because it would take radio waves about that long to get from Earth to the far side of Mercury's orbit, even if they could.)


HJ

Are you named for the auto?

I didn’t know about your Impressive interest in space exploration and rockets! I thought you were a comedian.

LOL!   :lol:


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
“Life isn’t fair but the government should be.”...Ann Richards, Governor of Texas

 
Posts: 60321 | Location: Frogville, Georgia USA | Mbr Since: 10-07-2003Reply With QuoteReport This Post
Chronic...
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Why, because I recycle stuff I found on the net? Smile   :)
(Actual comedians have to invent their own stuff, and on a more or less regular schedule. That's not my field.)

But, there is the occasional pun, which is of course its own reword.

What auto?
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Besides, how complicated can space be, when it's mostly empty?
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Look's like SpaceX has competition. The NASA page has an article about an upcoming test flight of Boeing’s Starliner, for carrying people into orbit, early next year.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Never goes away...
Picture of Reed N D Dark
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Next year? Can we nominate those to be left in space?
 
Posts: 10900 | Location: Central PA | Mbr Since: 05-14-2017Reply With QuoteReport This Post
Chronic...
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Nah, we wouldn't want to endanger the ones already there, would we?
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Water water everywhere but not a drop to drink

Water water everywhere but not a drop to drink

I can't get that link to work from a post.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Found an article talking about colonization of Titan (moon of Saturn) if and when people have a way of traveling that far.

Downside: it's a lot furthur than Mars; way colder than here; way less sunlight than here; much longer day than we're used to; way less surface gravity than Earth (less than Mars, even); hazy atmosphere.

Upside: air pressure higher than here (so no worry about decompression); hydrocarbons rain from the sky (some of them literally, hence the hazy atmosphere); water can be otained from environment but any near the surface will be ice of course; some of the time Titan is inside the magnetic field of Saturn (which blocks the solar wind); might be a good view of Saturn if the haze doesn't block that (but only if you're on the side that faces Saturn - it's tidally locked like our moon).

It's the only place outside Earth known to have stable pools of liquid on the surface - it has a methane cycle analogous to Earth's water cycle.

Seasons cycle with Saturn's orbit around the sun, so each season is some 30 times as long as on Earth.

It's surface temperature is comparable to the night-time low on Mercury, which is weird since Mercury is thought of as hot.

Oh, and the combination of low surface gravity and high air pressure means aircraft wings could be a lot shorter than on Earth.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Launch scheduled for Sunday evening, 7:27 PM EST, to send some crew to the ISS.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Launch in a few minutes.

On Discovery channel now.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Nominal!!
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Devoted...
Picture of That JR Thang
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What kinda place is this? No pictures? No links?

Make me go look it up all on my liddle lonesome...see how you do me.Wink   ;)


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fence straddlers get a crotch full of splinters -- Granny
 
Posts: 6582 | Location: Atlanta | Mbr Since: 05-01-2017Reply With QuoteReport This Post
Chronic...
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Links? No sausage here! Or did you mean golf? Smile   :)

NASA main page: https://www.nasa.gov

https://www.nasa.gov/content/n...pacex-crew-1-mission
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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Docking expected at 11 PM EST tonight.
 
Posts: 9668 | Location: Colorado | Mbr Since: 10-17-2003Reply With QuoteReport This Post
Chronic...
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They're docked! Over Idaho.
 
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