Traveller’s
Comments
(group member since Jan 14, 2015)
Traveller’s
comments
from the On Paths Unknown group.
Showing 1,701-1,720 of 2,761
To start things off, I'll copy and paste a bit from another thread: Trav said:
Nobody interested in Weir's obvious bit of showing off with "Hermes is powered by ion engines. They throw argon out the back of the ship really fast to get a tiny amount of acceleration. The thing is, it doesn’t take much reactant mass, so a little argon (and a nuclear reactor to power things) let us accelerate constantly the whole way there. You’d be amazed at how fast you can get going with a tiny acceleration over a long time."?
I wish my rocket science was good enough to really understand what he is saying there, compared to how spacecraft are currently driven forward. I know that orbital variables are carefully plotted, and it kind of goes without saying that once you are past the pull of gravity, that you won't need much to propel you forward - but... anyway, i suppose I'll have to try and read it up somewhere. Coz' i'm not just prepared to take his word for it - hoo boy, this might end up being a long read for me... XD
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Puddin Pt replied:
"Ion engines are very real, practical devices, and indeed very cool. If I remember my own rocket science correctly (which might be dicey, because I believe they're not rockets), his description is quite accurate: low acceleration, but extremely high fuel economy. This has made then useful for deep space missions in the 21st Century, and Earth satellites use them for station keeping as well. Today deep space missions are not powered by nuclear reactors, but by radioisotope thermoelectric generators, which use the heat of radioactive decay to generate electricity to propel the ions. A hypothetical manned mission might have to use a nuclear reactor, but to reach Mars photovoltaic arrays might be enough, too.
I love space science. Can you tell? ;) "
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Trav:
Next thing I'm wondering, is how realistic 124 days from Earth to Mars would be in today's terms.
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Puddin Pt :
How long a transit takes depends on the relative position of Mars from the Earth, of course, but also a lot of other factors including available fuels, yadda, yadda. The Interplanetary Transport Network can get you anywhere in the Solar System using remarkably little fuel, but takes a long time. So if a Mars-bound person's ship has a nuclear reaction and lots of xenon as fuel (and Mars is as close as it can possibly be.).. Maybe?
According to NASA 54.6M km is the closes approach of Mars, and the record speed for an ion thruster is 10km/s. My calculator says you could get there in 63 days. So 124 days sounds realistic.
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Thanks for that, Puddin!
Thanks, Puddin! (I love calling someone puddin... XD)Just in case we bore all of these non-sciencers, how about we go somewhere more suitable? Like here for example: https://www.goodreads.com/topic/show/...
(A thread for those inclined to discuss the S part of SF)
Hi everyone! Some of us find 'science' a Yyyaawwwn, and others think it's the next best thing after toast and peanut butter! If you fall in the latter category, (that is assuming you actually LIKE toast and peanut butter) then go no further. Come and camp out here and tell us(view spoiler) if you think Andy Weir has his science duckies in a row (and why you say so, of course).
Like a good little student, I'll be asking questions, and the science minded among you, can act as my.... (view spoiler) er... esteemed advisors.
I've had an idea! Shall we put all the "science" into a separate thread?
Puddin Pointy-Toes wrote: "Ion engines are very real, practical devices, and indeed very cool. If I remember my own rocket science correctly (which might be dicey, because I believe they're not rockets), his description is quite accurate: low acceleration,..."Yaye! I found someone! Now I can be lazy and just sponge off your brain, Puddin! XD (You're sounding suitably smart. ;) )
Next thing I'm wondering, is how realistic 124 days from Earth to Mars would be in today's terms.
Done. :)
Thanks for the interesting link, Ruth!I'm going to copy and paste a bit of conversation from the anything goes thread:
Amy said:
"The local mall has a 10 a.m. showing that is a third cheaper than any of their other showings, so I'm going to the movies after breakfast tomorrow. [...]
I think its fascinating to see a story take off like this, and it makes for a interesting overall cultural moment on several levels. I'm still musing on that; I might be able to unpack it a little more [...] once I've actually seen the movie."
Trav replied:
"Yes, I find it rather strange how Martian fever is suddenly bursting out all over the place. Our local mall has an 11AM showing, and irritatingly it is in 3D only - I prefer having a choice! ... I find that sometimes the 3D makes no difference, or is even irritating, and sometimes it's marvelous in 3D, so I'll go with the flow..."
Amy replied:
"It's a good thing you mentioned it, because I just double checked and the 10 a.m. IS in 3D! Why would anyone even do that that early in the morning?..."
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Well, I must say I was happy to see at least one other person agree with me that 3D isn't always the most desirable thing.
I'd be curious to know how the rest of you feel about 3-D.
Amy (Other Amy) wrote: "It's a good thing you mentioned it, because I just double checked and the 10 a.m. IS in 3D! Why would anyone even do that that early in the morning? In any case, I'll go to the 11:30 non-3D instead..."IKR?
Let's mention this 3D thing in the actual movie thread, shall we? I hope you don't mind if I copy and paste some of our convo there?
Well, while you mention it, the movie thread is here: https://www.goodreads.com/topic/show/...Yes, I find it rather strange how Martian fever is suddenly bursting out all over the place. Our local mall has an 11AM showing, and irritatingly it is in 3D only - I prefer having a choice! ... I find that sometimes the 3D makes no difference, or is even irritating, and sometimes it's marvelous in 3D, so I'll go with the flow...
PS, the coming Star Wars is another film I am DEFINITELY watching on big screen, maybe even I-Max
Yes! I just can't decide whether to chance it tomorrow and hope the crowds have subsided somewhat, or whether to wait until Sunday. I might want to join with some friends who will only be seeing it Sunday, so we'll see!My guess is that everybody and their cousin will be at the cinemas watching The Martian this weekend...
Amy (Other Amy) wrote: "Hello from Colorado, all. You have quite a few books on my TBR coming up and I am looking for a good discussion oriented group, so I thought I'd join up."Oh goodness, look who found us! It's not -that- Amy, it's OTHER Amy! :D
Welcome, Amy, I'm glad you found us. Hope you'll enjoy our group. We do everything seriously here, including having fun! :)))
Mark wrote: "There's just one thing on the science I am struggling with: In chapter one, a massive dust storm is threatening to topple the landing craft, and hurls some metal object into Watley's side, causing ..."Good catch about the winds and atmosphere there, Mark. Don't go away, you seem quite jacked up on your cosmology...
the gift wrote: "read it, gave it a three- which means yes I liked it- but the science stuff was fun, sounded real, sounded plausible, btw there is a critical perspective that suggests all early sf are 'robinsonade..."Interesting, indeed. Have you read Railsea by China Miéville? A fun skit on the "adventure novel" genre. Hmm, I'll have to think carefully about my HG Wells and Jules Verne reading background to see if I agree. Of course, from a structuralist perspective, all folk tales revolve around a quest, as Vladimir Propp will tell you in his book Morphology of the Folk Tale. :)
Nobody interested in Weir's obvious bit of showing off with "Hermes is powered by ion engines. They throw argon out the back of the ship really fast to get a tiny amount of acceleration. The thing is, it doesn’t take much reactant mass, so a little argon (and a nuclear reactor to power things) let us accelerate constantly the whole way there. You’d be amazed at how fast you can get going with a tiny acceleration over a long time."?I wish my rocket science was good enough to really understand what he is saying there, compared to how spacecraft are currently driven forward. I know that orbital variables are carefully plotted, and it kind of goes without saying that once you are past the pull of gravity, that you won't need much to propel you forward - but... anyway, i suppose I'll have to try and read it up somewhere. Coz' i'm not just prepared to take his word for it - hoo boy, this might end up being a long read for me... XD
That sounds lovely, Linda! I've never seen a book with color illustrations of Dickens, but we used to have a lovely leather set with black and white illustrations.I've been wondering how different continental (as in Spain) Spanish is from South American Spanish. I assume it doesn't make too much difference when you're reading it, but I assume there's quite a bit of difference in the spoken language and how it sounds. Can you make yourself easily understood in Spain?
Funny, that even though i was fine reading books with no pictures in them, i never lost my taste for illustrations. Illustrations draw me a like a moth to flame. I love color especially, I guess.Oh, and just btw, illustrations are the one thing why paper books must never die. I love the comfort of my e-books, but illustrations can never be the same on a screen. I want to have the paper under my fingers when it comes to images.
On second thought - maybe my mother caved in simply because i nagged her so much! XD
Oh, you know kids - they don't mind reading or watching or listening to things over and over again; so I just kept reading comics as much as I could with a disapproving father against me but a sympathetic mother on my side... :P
Right! So now the scienc-y people can start talking science! XD Heheheheheheh.What do you think of the means of locomotion, of the ion engine?
Oh, -that- ERB! Ya, I used to luuuurve the Tarzan comics when I was a kid, and of course I had once upon a time read the original as well, though it's become a bit hazy by now.Thanks for all the links - will investigate ASAP.
