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A Dream: Mercury in a Spacesuit

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  A Dream:  Mercury in a Spacesuit Joe Bernstein <joe@sfbooks.com> - 2016-02-16 08:42 -0800
    Re: A Dream:  Mercury in a Spacesuit Greg Goss <gossg@gossg.org> - 2016-02-16 17:20 -0700
      Re: A Dream:  Mercury in a Spacesuit "nuny@bid.nes" <Alien8752@gmail.com> - 2016-02-16 17:39 -0800
        Re: A Dream:  Mercury in a Spacesuit Cryptoengineer <treifamily@gmail.com> - 2016-02-16 23:39 -0600
        Re: A Dream:  Mercury in a Spacesuit David DeLaney <daviddelaney@earthlink.net> - 2016-02-17 03:49 -0600
      Re: A Dream:  Mercury in a Spacesuit "a425couple" <a425couple@hotmail.com> - 2016-02-16 19:34 -0800
      Re: A Dream:  Mercury in a Spacesuit Joe Bernstein <joe@sfbooks.com> - 2016-02-16 20:33 -0800
    Re: A Dream:  Mercury in a Spacesuit Butch Malahide <fred.galvin@gmail.com> - 2016-02-16 18:42 -0800
      Re: A Dream:  Mercury in a Spacesuit Don Kuenz <garbage@crcomp.net> - 2016-02-17 17:36 +0000
    Re: A Dream:  Mercury in a Spacesuit wdstarr@panix.com (William December Starr) - 2016-02-16 22:14 -0500
      Re: A Dream:  Mercury in a Spacesuit hamish.laws@gmail.com - 2016-02-16 19:26 -0800
      Re: A Dream:  Mercury in a Spacesuit Don Bruder <dakidd@sonic.net> - 2016-02-16 19:39 -0800
        Re: A Dream:  Mercury in a Spacesuit Joe Bernstein <joe@sfbooks.com> - 2016-02-16 21:24 -0800
          Re: A Dream:  Mercury in a Spacesuit Joe Bernstein <joe@sfbooks.com> - 2016-02-22 22:41 -0800
      Re: A Dream:  Mercury in a Spacesuit Cryptoengineer <treifamily@gmail.com> - 2016-02-16 23:46 -0600
        Re: A Dream:  Mercury in a Spacesuit wdstarr@panix.com (William December Starr) - 2016-02-18 22:58 -0500
        Re: A Dream:  Mercury in a Spacesuit Quadibloc <jsavard@ecn.ab.ca> - 2016-02-18 20:51 -0800
    Re: A Dream:  Mercury in a Spacesuit "a425couple" <a425couple@hotmail.com> - 2016-02-16 19:56 -0800
    Re: A Dream:  Mercury in a Spacesuit Quadibloc <jsavard@ecn.ab.ca> - 2016-02-17 00:47 -0800
      Re: A Dream:  Mercury in a Spacesuit Greg Goss <gossg@gossg.org> - 2016-02-17 02:13 -0700
        Re: A Dream:  Mercury in a Spacesuit Quadibloc <jsavard@ecn.ab.ca> - 2016-02-17 11:18 -0800
    Re: A Dream:  Mercury in a Spacesuit "a425couple" <a425couple@hotmail.com> - 2016-02-17 13:55 -0800
      Re: A Dream:  Mercury in a Spacesuit Robert Carnegie <rja.carnegie@excite.com> - 2016-02-18 01:58 -0800
        Re: A Dream:  Mercury in a Spacesuit Greg Goss <gossg@gossg.org> - 2016-02-18 09:48 -0700
        Re: A Dream:  Mercury in a Spacesuit wdstarr@panix.com (William December Starr) - 2016-02-18 23:04 -0500
          Re: A Dream:  Mercury in a Spacesuit Robert Carnegie <rja.carnegie@excite.com> - 2016-02-19 02:20 -0800
            Re: A Dream:  Mercury in a Spacesuit Cryptoengineer <treifamily@gmail.com> - 2016-02-19 23:30 -0600
    Re: A Dream:  Mercury in a Spacesuit peterwezeman@hotmail.com - 2016-03-14 18:38 -0700
      Re: A Dream:  Mercury in a Spacesuit Greg Goss <gossg@gossg.org> - 2016-03-14 20:28 -0600
      Re: A Dream:  Mercury in a Spacesuit wdstarr@panix.com (William December Starr) - 2016-03-18 11:45 -0400
        Re: A Dream:  Mercury in a Spacesuit ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2016-03-18 16:13 +0000
        Re: A Dream:  Mercury in a Spacesuit Robert Carnegie <rja.carnegie@excite.com> - 2016-03-18 09:48 -0700
          Re: A Dream:  Mercury in a Spacesuit Peter Trei <petertrei@gmail.com> - 2016-03-18 09:57 -0700
        Re: A Dream:  Mercury in a Spacesuit Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2016-03-18 19:48 +0100
          Re: A Dream:  Mercury in a Spacesuit Kevrob <kevrob@my-deja.com> - 2016-03-18 12:10 -0700
        Re: A Dream:  Mercury in a Spacesuit Steve Coltrin <spcoltri@omcl.org> - 2016-03-21 19:20 -0600
          Re: A Dream:  Mercury in a Spacesuit David DeLaney <daviddelaney@earthlink.net> - 2016-03-22 15:16 -0500
            Re: A Dream:  Mercury in a Spacesuit Robert Carnegie <rja.carnegie@excite.com> - 2016-03-22 14:12 -0700
            Re: A Dream:  Mercury in a Spacesuit Steve Coltrin <spcoltri@omcl.org> - 2016-03-24 10:48 -0600

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#433355 — A Dream: Mercury in a Spacesuit

So I've been having this recurring dream lately and I'm curious about 
some questions related to it.

The dream involves me in a spacesuit (conveniently ignoring the usual 
physical discomforts) in orbit around the planet Mercury.  I'm near, 
possibly tethered to, the vehicle that got me there, which is basically 
just an open framework that connected me to a rocket or some such.  It's 
pretty obvious that I'm doomed, but just how - boiling in the sunlight, 
frying in the actual Sun, or simply awaiting suffocation - is less 
clear, and anyway I always wake up before it happens (though sometimes 
parts of my spacesuit start evaporating before I do).

The proximate reason this dream takes this form is very obviously 
written science fiction; it's a delayed response to the way Flandry and 
Chives escape a bad situation in <A Stone in Heaven>.  (The reason I'm 
*having* the dream right about now is probably that I'm unemployed 
during what's normally my most employable time of the year, but anyway.)

I'm curious about some technical aspects - is it really possible to 
orbit Mercury at all, stably I mean, or would I inevitably get sucked 
into a solar orbit, a crash on Mercury, or the Sun itself?  If I *could* 
stick to Mercury, is it possible to stay in darkness?  (I'm pretty sure 
not.)  How would I actually die?  Stuff like that.  But yes, I do know 
where rec.arts.sf.science is.

So this post is mainly a pseudo-YASID.  Where else besides <A Stone in 
Heaven> and, I suppose, the movie <Gravity> do people actually go 
meaningful distances in spacesuits?  How does that work?  (I mean, how'd 
I *get* to Mercury without exhausting my air?)  For that matter, how 
much is there about other ways to visit Mercury inadequately prepared, 
and what happens next?

And above all, what is there in written science fiction that conveys the 
sheer terror of space in a spacesuit even as well as <Gravity> does, let 
alone better?  <A Stone in Heaven> certainly doesn't go there.

Joe Bernstein

-- 
Joe Bernstein, tax preparer and writer                 <joe@sfbooks.com>

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#433388

Joe Bernstein <joe@sfbooks.com> wrote:

>I'm curious about some technical aspects - is it really possible to 
>orbit Mercury at all, stably I mean, or would I inevitably get sucked 
>into a solar orbit, a crash on Mercury, or the Sun itself?  If I *could* 
>stick to Mercury, is it possible to stay in darkness?  (I'm pretty sure 
>not.)

One of the LaGrange points (quick google:  L2) is behind Mercury, but
I can't tell if it would be far enough out that you'd still see the
large sun AROUND Mercury.



> How would I actually die?  Stuff like that.  But yes, I do know 
>where rec.arts.sf.science is.

Most Apollo generation suits achieved cooling by venting air out (past
sweaty body or limbs first) of wrist or ankle vents.  So you'd
probably die from running out of air.  Suits are generally pretty
silvery, so that should cut down a large amount of the insolation
you're receiving.  I don't think you'd get failure of plastic or
rubber bits in the heat, followed by pressure failure.

>So this post is mainly a pseudo-YASID.  Where else besides <A Stone in 
>Heaven> and, I suppose, the movie <Gravity> do people actually go 
>meaningful distances in spacesuits?  How does that work?  (I mean, how'd 
>I *get* to Mercury without exhausting my air?)  For that matter, how 
>much is there about other ways to visit Mercury inadequately prepared, 
>and what happens next?

Suited people riding on framework "space sleds" are pretty common in
SF.  You've probably got a major spaceship somewhere near and were
using the sled to accomplish some local mission.

>
>And above all, what is there in written science fiction that conveys the 
>sheer terror of space in a spacesuit even as well as <Gravity> does, let 
>alone better?  <A Stone in Heaven> certainly doesn't go there.

"Dutchman!  Dutchman!"  An attempted murder in one of the Honor
Harrington books involves sabotaging a suit's motors to send the user
off beyond the limits of her short-range radio.  This happens often
enough ot have a standard emergency phrase to cover the situation,
though the odds of recovery are generally not good.  The wild
gyrations before her suit motor runs out of fuel leave her stomach
contents across her visor, so she cannot even see where she's going.
-- 
We are geeks.  Resistance is voltage over current.

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#433389

On Tuesday, February 16, 2016 at 4:21:03 PM UTC-8, Greg Goss wrote:
> Joe Bernstein <joe@sfbooks.com> wrote:
> 
> >I'm curious about some technical aspects - is it really possible to 
> >orbit Mercury at all, stably I mean, or would I inevitably get sucked 
> >into a solar orbit, a crash on Mercury, or the Sun itself?  If I *could* 
> >stick to Mercury, is it possible to stay in darkness?  (I'm pretty sure 
> >not.)
> 
> One of the LaGrange points (quick google:  L2) is behind Mercury, but
> I can't tell if it would be far enough out that you'd still see the
> large sun AROUND Mercury.

  According to this:

http://space.stackexchange.com/questions/3565/are-there-any-lagrange-points-in-the-solar-system-in-perpetual-shade

  only Mars and the planets farther out have their L2 points in full shade.

  AFAIK there's no reason one couldn't orbit Mercury stably if you stay close enough- its Hill sphere is ~250K km:

https://en.wikipedia.org/wiki/Hill_sphere#/media/File:Hill_sphere_of_the_planets.png

> > How would I actually die?  Stuff like that.  But yes, I do know 
> >where rec.arts.sf.science is.
> 
> Most Apollo generation suits achieved cooling by venting air out (past
> sweaty body or limbs first) of wrist or ankle vents.  So you'd
> probably die from running out of air.  Suits are generally pretty
> silvery, so that should cut down a large amount of the insolation
> you're receiving.  I don't think you'd get failure of plastic or
> rubber bits in the heat, followed by pressure failure.

  Yep, unless the suit incorporates some sort of active radiator (so that you could live long enough for it to fail so you could then broil to death), but that gets into suit-as-spaceship territory.

> >So this post is mainly a pseudo-YASID.  Where else besides <A Stone in 
> >Heaven> and, I suppose, the movie <Gravity> do people actually go 
> >meaningful distances in spacesuits?  How does that work?

  Mission To Mars (the film with Gary Sinise) has a scene in which a group of suited people have to "fly" some few km from their crippled spaceship to a resupply module.

> > (I mean, how'd 
> >I *get* to Mercury without exhausting my air?)  For that matter, how 
> >much is there about other ways to visit Mercury inadequately prepared, 
> >and what happens next?
> 
> Suited people riding on framework "space sleds" are pretty common in
> SF.  You've probably got a major spaceship somewhere near and were
> using the sled to accomplish some local mission.

  Maybe he's a construction worker on the Mercury Darkside Beanstalk?

> >And above all, what is there in written science fiction that conveys the 
> >sheer terror of space in a spacesuit even as well as <Gravity> does, let 
> >alone better?  <A Stone in Heaven> certainly doesn't go there.
> 
> "Dutchman!  Dutchman!"  An attempted murder in one of the Honor
> Harrington books involves sabotaging a suit's motors to send the user
> off beyond the limits of her short-range radio.  This happens often
> enough ot have a standard emergency phrase to cover the situation,
> though the odds of recovery are generally not good.  The wild
> gyrations before her suit motor runs out of fuel leave her stomach
> contents across her visor, so she cannot even see where she's going.

  The scene in MTM isn't quite that hectic, but it's close. There's a lot of heavy breathing that speeds up as the action intensifies, and it nicely conveys the actors' apprehension.

  Niven's _Becalmed In Hell_ has a suited character walking around on his sentient bathysphere's hull to do some maintenance while deep in Venus' atmosphere (not exactly in space, but still). In his typically dry style Niven conveys the tension of that task very well.

  Also, _Have Space Suit - Will Travel_.


  Mark L. Fergerson

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#433405

"nuny@bid.nes" <Alien8752@gmail.com> wrote in
news:608b7051-70fa-4c6c-9430-7569e2d65259@googlegroups.com: 

> On Tuesday, February 16, 2016 at 4:21:03 PM UTC-8, Greg Goss wrote:
>> Joe Bernstein <joe@sfbooks.com> wrote:
>> 
>> >I'm curious about some technical aspects - is it really possible to 
>> >orbit Mercury at all, stably I mean, or would I inevitably get
>> >sucked into a solar orbit, a crash on Mercury, or the Sun itself? 
>> >If I *could* 
>  
>> >stick to Mercury, is it possible to stay in darkness?  (I'm pretty
>> >sure 
>  
>> >not.)
>> 
>> One of the LaGrange points (quick google:  L2) is behind Mercury, but
>> I can't tell if it would be far enough out that you'd still see the
>> large sun AROUND Mercury.
> 
>   According to this:
> 
> http://space.stackexchange.com/questions/3565/are-there-any-lagrange-po
> ints-in-the-solar-system-in-perpetual-shade 
> 
>   only Mars and the planets farther out have their L2 points in full
>   shade. 
> 
>   AFAIK there's no reason one couldn't orbit Mercury stably if you
>   stay close enough- its Hill sphere is ~250K km: 

Indeed - the MESSENGER probe spent 4 years in orbit around Mercury.

pt

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#433416

On 2016-02-17, nuny@bid.nes <Alien8752@gmail.com> wrote:
>   Niven's _Becalmed In Hell_ has a suited character walking around on his
> sentient bathysphere's hull to do some maintenance while deep in Venus'
> atmosphere (not exactly in space, but still). In his typically dry style
> Niven conveys the tension of that task very well.
>
>   Also, _Have Space Suit - Will Travel_.

And I recall that the human-aliens in Robinson's _Stardance_ trilogy would
probably fit, if you identify their covering silvery symbiotes with
"spacesuits". Also John Varley, come to think of it?

Dave
-- 
\/David	DeLaney	posting	thru EarthLink - "It's not the pot that	grows the flower
It's not the clock that	slows the hour 	The definition's plain for anyone to see
Love is	all it takes to	make a family" - R&P. VISUALIZE	HAPPYNET VRbeable<BLINK>
http://gatekeeper.vic.com/~dbd/	-net.legends/Magic / I WUV you in all CAPS! --K.

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#433399

"Greg Goss" <gossg@gossg.org> wrote in message...
> Joe Bernstein <joe@sfbooks.com> wrote:
>>So this post is mainly a pseudo-YASID.  Where else besides <A Stone in 
>>Heaven> and, I suppose, the movie <Gravity> do people actually go 
>>meaningful distances in spacesuits?  How does that work?  (I mean, how'd 
>>I *get* to Mercury without exhausting my air?)  For that matter, how 
>>much is there about other ways to visit Mercury inadequately prepared, 
>>and what happens next?
> 
> Suited people riding on framework "space sleds" are pretty common in
> SF.  You've probably got a major spaceship somewhere near and were
> using the sled to accomplish some local mission.

For what ever value it is worth, 
In Arthur Clarke's "The Hammer of God" 
two men ride such a sled out about 1,000 km (660 miles) 
to watch an event, and then back to the space ship again.

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#433402

On Tuesday, February 16, 2016 at 4:21:03 PM UTC-8, Greg Goss wrote:

> Joe Bernstein <joe@sfbooks.com> wrote:

> >I'm curious about some technical aspects - is it really possible to 
> >orbit Mercury at all, stably I mean, or would I inevitably get sucked 
> >into a solar orbit, a crash on Mercury, or the Sun itself?  If I *could* 
> >stick to Mercury, is it possible to stay in darkness?  (I'm pretty sure 
> >not.)

It was very kind of y'all not to point out to me that I had proportions 
all wrong.  Somehow I'd come to see Mercury as being right at the edge 
of the Sun, more or less, when in fact the Sun's width is always less 
than a third that of Mercury's orbit.  So yes, when I wrote about 
imagining that I'd fry in the Sun itself, that's because some 
iterations of the dream actually have me floating right toward the 
nearby plasma.  My *conscious* self probably should have spent that 
hour with Wikipedia before posting.  Sorry!

> >So this post is mainly a pseudo-YASID.  Where else besides <A Stone in 
> >Heaven> and, I suppose, the movie <Gravity> do people actually go 
> >meaningful distances in spacesuits?  How does that work?  (I mean, how'd 
> >I *get* to Mercury without exhausting my air?)

> Suited people riding on framework "space sleds" are pretty common in
> SF.  You've probably got a major spaceship somewhere near and were
> using the sled to accomplish some local mission.

Early versions of the dream did have me abandoned by my mission, 
possibly related to the amount of betrayal by friends and associates 
that went into the unemployment.  In at least one later version I'd 
volunteered for a suicide run (let's not discuss that one), and more 
recently still it just doesn't come up.

Joe Bernstein

-- 
Joe Bernstein, tax preparer and writer                 <joe@sfbooks.com>

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#433392

On Tuesday, February 16, 2016 at 10:42:21 AM UTC-6, Joe Bernstein wrote:
> So this post is mainly a pseudo-YASID.  Where else besides <A Stone in 
> Heaven> and, I suppose, the movie <Gravity> do people actually go 
> meaningful distances in spacesuits?  How does that work?  (I mean, how'd 
> I *get* to Mercury without exhausting my air?)  For that matter, how 
> much is there about other ways to visit Mercury inadequately prepared, 
> and what happens next?
> 
> And above all, what is there in written science fiction that conveys the 
> sheer terror of space in a spacesuit even as well as <Gravity> does, let 
> alone better?  <A Stone in Heaven> certainly doesn't go there.

Here are three memorable stories on the terror-in-a-spacesuit theme.

Robert A. Heinlein's "Ordeal in Space"
Ray Bradbury's "Kaleidoscope"
Bryce Walton's "To Each His Star" (available at Project Gutenberg)

Pleasant dreams!

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#433427

Butch Malahide <fred.galvin@gmail.com> wrote:
> On Tuesday, February 16, 2016 at 10:42:21 AM UTC-6, Joe Bernstein wrote:
>> So this post is mainly a pseudo-YASID.  Where else besides <A Stone in
>> Heaven> and, I suppose, the movie <Gravity> do people actually go
>> meaningful distances in spacesuits?  How does that work?  (I mean, how'd
>> I *get* to Mercury without exhausting my air?)  For that matter, how
>> much is there about other ways to visit Mercury inadequately prepared,
>> and what happens next?
>>
>> And above all, what is there in written science fiction that conveys the
>> sheer terror of space in a spacesuit even as well as <Gravity> does, let
>> alone better?  <A Stone in Heaven> certainly doesn't go there.
>
> Here are three memorable stories on the terror-in-a-spacesuit theme.
>
> Robert A. Heinlein's "Ordeal in Space"
> Ray Bradbury's "Kaleidoscope"
> Bryce Walton's "To Each His Star" (available at Project Gutenberg)
>
> Pleasant dreams!

Allow me to add my thank you to Joe Berstein's for the "Kaleidoscope"
reminder. The other two stories that you mention are now on my "to be
read" list.

In another part of this thread Joe Berstein more or less says that his
dream frightens him more than "Kaleidoscope." That "horror lite" aspect
of both Bradbury and Poe enable those authors to go down easy for me.
YMMV.

--
Don Kuenz KB7RPU

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#433395

In article <2366abdc-80e5-468c-a9af-2da2d0cad29e@googlegroups.com>,
Joe Bernstein <joe@sfbooks.com> said:

> I'm curious about some technical aspects - is it really possible
> to orbit Mercury at all, stably I mean, or would I inevitably get
> sucked into a solar orbit, a crash on Mercury, or the Sun itself?

I Could Be Wrong, but I'm pretty sure that if Body_1 is in a stable
orbit around Body_2 then by definition it's possible for Body_3 to
find a stable orbit around Body_1 --

   which is a lot easier to parse if I change it to "if PLANET is in
   a stable orbit around STAR then by definition it's possible for
   SMALLER_THING to find a stable orbit around PLANET.

-- as long as it's feasible to think of all three as point-masses
anyway, so you don't have to worry about "Will that third thing
_fit_ inbetween the first two?"

(And assume that the medium is a vacuum.  Your mileage may vary
inside, say, Karl Schroeder's air-filled Virga construct.)

-- wds

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#433397

On Wednesday, February 17, 2016 at 2:14:28 PM UTC+11, William December Starr wrote:
> I Could Be Wrong, but I'm pretty sure that if Body_1 is in a stable
> orbit around Body_2 then by definition it's possible for Body_3 to
> find a stable orbit around Body_1 --
> 

I'm pretty confident that's going to depend on the masses of the objects involved (especially body 1 and body 2.
Get it in the right position and velocity and a piece of gravel could get into a stable orbit of the earth.
I don't think it's going to be overly possible for anything to orbit the piece of gravel.

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#433400

In article <na0oii$fag$1@panix2.panix.com>,
 wdstarr@panix.com (William December Starr) wrote:

> In article <2366abdc-80e5-468c-a9af-2da2d0cad29e@googlegroups.com>,
> Joe Bernstein <joe@sfbooks.com> said:
> 
> > I'm curious about some technical aspects - is it really possible
> > to orbit Mercury at all, stably I mean, or would I inevitably get
> > sucked into a solar orbit, a crash on Mercury, or the Sun itself?
> 
> I Could Be Wrong, but I'm pretty sure that if Body_1 is in a stable
> orbit around Body_2 then by definition it's possible for Body_3 to
> find a stable orbit around Body_1 --
> 
>    which is a lot easier to parse if I change it to "if PLANET is in
>    a stable orbit around STAR then by definition it's possible for
>    SMALLER_THING to find a stable orbit around PLANET.
> 
> -- as long as it's feasible to think of all three as point-masses
> anyway, so you don't have to worry about "Will that third thing
> _fit_ inbetween the first two?"
> 
> (And assume that the medium is a vacuum.  Your mileage may vary
> inside, say, Karl Schroeder's air-filled Virga construct.)
> 
> -- wds

But only if the penguin is assumed to be a sphere, right?

-- 
Security provided by Mssrs Smith and/or Wesson. Brought to you by the letter Q

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#433404

On Tuesday, February 16, 2016 at 7:39:18 PM UTC-8, Don Bruder wrote:

> In article <na0oii$fag$1@panix2.panix.com>,
>  wdstarr@panix.com (William December Starr) wrote:

> > In article <2366abdc-80e5-468c-a9af-2da2d0cad29e@googlegroups.com>,
> > Joe Bernstein <joe@sfbooks.com> said:

> > > I'm curious about some technical aspects - is it really possible
> > > to orbit Mercury at all, stably I mean, or would I inevitably get
> > > sucked into a solar orbit, a crash on Mercury, or the Sun itself?

> > I Could Be Wrong, but I'm pretty sure that if Body_1 is in a stable
> > orbit around Body_2 then by definition it's possible for Body_3 to
> > find a stable orbit around Body_1 --

> > -- as long as it's feasible to think of all three as point-masses
> > anyway, so you don't have to worry about "Will that third thing
> > _fit_ inbetween the first two?"

> But only if the penguin is assumed to be a sphere, right?

In that hour I spent on Wikipedia, I was unnerved by the number of times 
it was mentioned casually that an object without propulsive power by 
definition could not be stable in orbit.

This theme recurs in the article about Messenger, for example.

So the specific notion I had - that the big bad Sun would steal me away - 
is probably not too much of a concern, but the more general notion that 
Things Go Wrong seems relevant.  I also noticed Messenger's moves to 
shed heat.  Sooner or later, my spacesuit would notably *fail* to shed 
heat, and I assume the effects would do nasty things to stability.  Not 
that I'd, y'know, be present to notice.

Joe Bernstein
who found "Kaleidoscope" rather less scary than the dream, actually, and 
even that isn't nearly as scary as J. Random Horror Movie.  Guess that 
shows I'm middle-aged.  Anyway, thank you, Butch Malahide.
   Turns out that the university library I'm writing from has nine of 
Heinlein's juveniles.  Between that, the public library's offerings, 
and just maybe my finding in storage the omnibus I have, I may be able 
at last to read 'em in order.  Which would put <Have Space Suit> fairly 
late in the list.
   "Ordeal in Space" looks to be more of a challenge, but at worst, I've 
read it before.

-- 
Joe Bernstein, tax preparer and writer                 <joe@sfbooks.com>

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#433890

Almost a week ago, I wrote:

> but the more general notion that 
> Things Go Wrong seems relevant.

And then it only dawned on me a day or two ago that one thing that is 
pretty much guaranteed to go wrong is radiation damage.  Solar wind, 
y'know.  Unless Mercury has a much more effective magnetic field than 
I thought, and I'm within it.

If my spacesuit happens *not* to cool by ejecting air, I still suspect 
I'll run out of oxygen before I die of radiation, but it is another 
factor to consider.

Since it's pretty specific to the location (I'm pretty sure radiation 
would take *MUCH* longer to kill me in Mars orbit, say), I'm guessing 
this particular angle hasn't been written about much, although of 
course there's the ending of Michael Flynn's <Falling Stars> to 
consider.  ("Inconstant Moon" doesn't count because there's not only a 
magnetic field but an atmosphere, it's just that neither is enough.)

Joe Bernstein

-- 
Joe Bernstein, tax preparer and writer                 <joe@sfbooks.com>

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#433406

wdstarr@panix.com (William December Starr) wrote in news:na0oii$fag$1
@panix2.panix.com:

> In article <2366abdc-80e5-468c-a9af-2da2d0cad29e@googlegroups.com>,
> Joe Bernstein <joe@sfbooks.com> said:
> 
>> I'm curious about some technical aspects - is it really possible
>> to orbit Mercury at all, stably I mean, or would I inevitably get
>> sucked into a solar orbit, a crash on Mercury, or the Sun itself?
> 
> I Could Be Wrong, but I'm pretty sure that if Body_1 is in a stable
> orbit around Body_2 then by definition it's possible for Body_3 to
> find a stable orbit around Body_1 --
> 
>    which is a lot easier to parse if I change it to "if PLANET is in
>    a stable orbit around STAR then by definition it's possible for
>    SMALLER_THING to find a stable orbit around PLANET.
> 
> -- as long as it's feasible to think of all three as point-masses
> anyway, so you don't have to worry about "Will that third thing
> _fit_ inbetween the first two?"

Well, no. The Wikipedia "Hill Sphere" article enlightened me on this.
The "Hill Sphere" is the volume in which a stable orbit can be 
established around a body. For (for example) the Space Shuttle, this
is much smaller than the object itself (12 cm or so???? in diameter)

pt
 

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#433548

In article <XnsA5B11238E663Cmelchizedek@216.166.97.131>,
Cryptoengineer <treifamily@gmail.com> said:

> wdstarr@panix.com (William December Starr) wrote 
> 
>> I Could Be Wrong, but I'm pretty sure that if Body_1 is in a stable
>> orbit around Body_2 then by definition it's possible for Body_3 to
>> find a stable orbit around Body_1 --
>> 
>>    which is a lot easier to parse if I change it to "if PLANET is in
>>    a stable orbit around STAR then by definition it's possible for
>>    SMALLER_THING to find a stable orbit around PLANET.
>> 
>> -- as long as it's feasible to think of all three as point-masses
>> anyway, so you don't have to worry about "Will that third thing
>> _fit_ inbetween the first two?"
>
> Well, no. The Wikipedia "Hill Sphere" article enlightened me on this.
> The "Hill Sphere" is the volume in which a stable orbit can be 
> established around a body. For (for example) the Space Shuttle, this
> is much smaller than the object itself (12 cm or so???? in diameter)

Well I _did_ say that bit about thinking of them all as
point-masses, on account of physics is so much more elegant than
engineering.  But basically, okay, I was wrong.

-- wds

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#433552

On Tuesday, February 16, 2016 at 10:46:56 PM UTC-7, Cryptoengineer wrote:

> Well, no. The Wikipedia "Hill Sphere" article enlightened me on this.
> The "Hill Sphere" is the volume in which a stable orbit can be 
> established around a body. For (for example) the Space Shuttle, this
> is much smaller than the object itself (12 cm or so???? in diameter)

Read the article. It was 120 cm, because the Shuttle is in LEO. But it the 
Shuttle somehow travelled 'way up to geosynchronous orbit, there would be no 
problem in orbiting it - since the Hill Sphere is all about the gravitational 
influence of other bodies - particularly the primary - overwhelming that of the 
body one is thinking of orbiting.

John Savard

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#433401

"Joe Bernstein" <joe@sfbooks.com> wrote in message...
> So I've been having this recurring dream lately and I'm curious about 
> some questions related to it.
> The dream involves me in a spacesuit (conveniently ignoring the usual 
> physical discomforts) in orbit around the planet Mercury.  I'm near, 
> possibly tethered to, the vehicle that got me there, which is basically 
> just an open framework that connected me to a rocket or some such.  It's 
> pretty obvious that I'm doomed, but just how - boiling in the sunlight, 
> frying in the actual Sun, or simply awaiting suffocation - is less 
> clear, and anyway I always wake up before it happens ---- 

> I'm curious about some technical aspects - is it really possible to 
> orbit Mercury at all, stably I mean, 

Sure, that would be fine & stable. 
Besides looking at this source, see the graphic and note 
the "sunshade"
https://en.wikipedia.org/wiki/MESSENGER

> and, I suppose, the movie <Gravity> do people actually go 
> meaningful distances in spacesuits?  How does that work?  

A standard 'space suit' perhaps is " Each EMU has two oxygen tanks 
(similar to scuba diving tanks) that work with a carbon dioxide 
removal system to allow a 6 to 8.5 hour spacewalk." 
But that EVA 'sled' of yours could carry a lot more!! 

>   (The reason I'm 
> *having* the dream right about now is probably that I'm unemployed 
> during what's normally my most employable time of the year, but anyway.)
> Joe Bernstein, tax preparer and writer                 <joe@sfbooks.com>

Best of luck and good wishes to you, 
seems like there should still be time to find that work.

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#433413

On Tuesday, February 16, 2016 at 9:42:21 AM UTC-7, Joe Bernstein wrote:

> And above all, what is there in written science fiction that conveys the 
> sheer terror of space in a spacesuit even as well as <Gravity> does, let 
> alone better?  <A Stone in Heaven> certainly doesn't go there.

I'm not sure, but Arthur C. Clarke's "A Transit of Earth" might do so.

Because Mercury has a solid surface, after Mars, it would be the next planet 
(at one point, that honor would go to Pluto) on which an astronaut could 
conceivably land and walk - since Venus, as well as the gas giants, is right 
out the window.

However, I was thinking that this could be done using the same technique 
applied to the Apollo moon landings - land at the right time of the local "day" 
for the most survivable conditions. Just after sunset, to escape the Sun's 
radiation, came to mind.

It turns out, though, that even then, Mercury is very cold, as it starts 
cooling off when the Sun is low in the sky. So the astronauts would have to 
take a source of heat with them.

John Savard

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#433415

Quadibloc <jsavard@ecn.ab.ca> wrote:

[moving the thread from orbit to the surface]

>However, I was thinking that this could be done using the same technique 
>applied to the Apollo moon landings - land at the right time of the local "day" 
>for the most survivable conditions. Just after sunset, to escape the Sun's 
>radiation, came to mind.
>
>It turns out, though, that even then, Mercury is very cold, as it starts 
>cooling off when the Sun is low in the sky. So the astronauts would have to 
>take a source of heat with them.

Astronauts ARE a source of heat.  You have a good vacuum insulator,
and a large engine burning carbohydrates and other substances for
power.
-- 
We are geeks.  Resistance is voltage over current.

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