@S1-A.ARPA,@MIT-MC:hqm@SCRC-STONY-BROOK.ARPA (05/02/85)
From: Henry Minsky <hqm@SCRC-STONY-BROOK.ARPA> This is something I have wondered about for a long time: If you are in the middle of a large air-filled room in zero-g, and you find yourself with no velocity, is it possible to "swim" to one of the walls, i.e., by flapping your arms, kicking your legs, waving your shirt... I know various s-f authors have speculated on this situation, but I want to know if any of the astronauts really reported on this situation.
warner@orca.UUCP (Ken Warner) (05/05/85)
[BUGS] I have often wondered if swim-fin like shoes would be effective. Ken Warner
brent@phoenix.UUCP (Brent P. Callaghan) (05/06/85)
There's a very good book called "A House in Space" (sorry - can't
remember author/publisher) which describes the experiences of
the skylab crews.
The accounts of living in a weightless environment are quite
fascinating. They had to be careful they didn't inhale small
object (nuts, bolts, erasers etc). Most of us have witnessed
their space gymnastics performances and running around the
inside of the lab cylinder in self created "gravity".
In this book they describe the problem of drifting away
from handholds while engrossed in some activity.
They COULD swim back to the wall using a vigorous dog-paddle
technique.
--
Made in New Zealand --> Brent Callaghan
AT&T Information Systems, Lincroft, NJ
{ihnp4|mtuxo|pegasus}!phoenix!brent
(201) 576-3475markb@sdcrdcf.UUCP (Mark Biggar) (05/07/85)
How about blowing?
Mark Biggar
{allegra,burdvax,cbosgd,hplabs,ihnp4,akgua,sdcsvax}!sdcrdcf!markb@S1-A.ARPA:host.MIT-MC.ARPA (05/09/85)
From: JimDay.Pasa@Xerox.ARPA Why not give each astronaut a beany hat equipped with a small propellor and a windup motor?
polard@fortune.UUCP (Henry Polard) (05/10/85)
In article <1637@mordor.UUCP> @S1-A.ARPA,@MIT-MC:hqm@SCRC-STONY-BROOK.ARPA writes: >From: Henry Minsky <hqm@SCRC-STONY-BROOK.ARPA> > > > This is something I have wondered about for a long time: If you are >in the middle of a large air-filled room in zero-g, and you find >yourself with no velocity, is it possible to "swim" to one of the walls, >i.e., by flapping your arms, kicking your legs, waving your shirt... I heard that the Challenger astronoauts could move around with a rapid doggie-paddle swimming stroke. I guess moving in air is somewhat like moving in water. You might also move yourself by blowing hard. -- Henry Polard (You bring the flames - I'll bring the marshmallows.) {ihnp4,cbosgd,amd}!fortune!polard N.B: The words in this posting do not necessarily express the opinions of me, my employer, or any AI project.
ee163ahj@sdcc13.UUCP (PAUL VAN DE GRAAF) (05/11/85)
[] Pardon me for suggesting, but couldn't the astronaut just relieve himself (herself) in the opposite direction. While this rather messy, and certainly more embarassing than removing his shorts. I'm sure it would be effective, and if he's stuck there, the call to nature will come along soon enough. A bit faster and just as directional as blowing/whistling might be. I'm sorry I brought it up... Paul van de Graaf sdcsvax!sdcc13!ee163ahj U. C. San Diego
warner@orca.UUCP (Ken Warner) (05/11/85)
[BUGS] A while back, I made a suggestion of little note regarding getting caught with your velocity down. It was to arm each astronaut with a spring loaded dart gun. The dart would have some sticky stuff on the end and would trail a light weight line. It was proposed to be used on EVA's in the event the jet pack failed. But here is another chance to disregard the idea. :^> Ken Warner
al@aurora.UUCP (Al Globus) (05/14/85)
This is a non-problem, unless the astronaut is exactly at the center of mass of the space vehicle. If the center of mass is at a different place the astronaut will have a slightly different orbit around the Earth and will eventually reach the side of the space ship.
sewilco@mecc.UUCP (Scot E. Wilcoxon) (05/15/85)
If one gets stuck in free-fall in an atmosphere, at least Skylab's swimming technique should work. Shuttle crew can "easily" test other methods (including drifting to air intake vents). Getting stuck "motionless" in vacuum is another matter. But if one got stuck there by pushing another mass away, won't the astronaut and the mass meet again in one orbit? I'm sure someone reading this knows with more certainty than I, but I think the two orbits will cross. I'm not as certain about their being at the same place at the same time. (Let's not bring up the shuttle satellite launches..the shuttle uses rockets to move away from satellite, and satellite motors [usually] also force them into other orbits)
sean@ukma.UUCP (Sean Casey) (05/22/85)
In article <129@mecc.UUCP> sewilco@mecc.UUCP (Scot E. Wilcoxon) writes: > >Getting stuck "motionless" in vacuum is another matter. But >if one got stuck there by pushing another mass away, won't >the astronaut and the mass meet again in one orbit? I'm sure >someone reading this knows with more certainty than I, but I >think the two orbits will cross. If the Astronaut threw a mass in exactly the same line of his orbit, they would meet again eventually, but the Astronaut would be long dead from lack of air. Assuming the astronaut threw a 30 MPH pitch with the mass, it would have to circumscribe a circle much larger than the circumference of the earth, at a speed of 30 MPH. It would be more than 35 days before the object made it back around. If the course of the object deviated from the "orbit line" in the slightest, the chances of the two ever meeting again are, uh, astronomical. -- - Sean Casey UUCP: {cbosgd,anlams,hasmed}!ukma!sean - Department of Mathematics ARPA: ukma!sean@ANL-MCS.ARPA - University of Kentucky
dkatz@zaphod.UUCP (Dave Katz) (05/22/85)
In article <129@mecc.UUCP> sewilco@mecc.UUCP (Scot E. Wilcoxon) writes: > ... >Getting stuck "motionless" in vacuum is another matter. But >if one got stuck there by pushing another mass away, won't >the astronaut and the mass meet again in one orbit? I'm sure >someone reading this knows with more certainty than I, but I >think the two orbits will cross. ..... Depend partly on what you mean by "crossing". If the objects are not of equal mass, the lighter one will have a greater velocity (conservation of momentum), and hence a lower orbit since the radius of orbit is inversly proportional to the velocity. This gets more complex with considerations of the angle, relative to the direction of travel, etc. leading to elliptical orbits, etc. but will only apply as stated if both bodies have the same mass.
brent@phoenix.UUCP (Brent P. Callaghan) (05/23/85)
Al Globus writes: > This is a non-problem, unless the astronaut is exactly at the center of > mass of the space vehicle. If the center of mass is at a different place > the astronaut will have a slightly different orbit around the Earth and > will eventually reach the side of the space ship. Surely this depends on whether the spacecraft has earth synchronous rotation or not. A three axis stabilized spacecraft pointing its instruments at various stellar objects does not rotate. If the center of mass of such a spacecraft is in a circular orbit, then points distributed about this point will be in various elliptical orbits which maintain a constant separation. If we assume a polar or equatorial orbit, wouldn't the perturbations be negligible ? -- Made in New Zealand --> Brent Callaghan AT&T Information Systems, Lincroft, NJ {ihnp4|mtuxo|pegasus}!phoenix!brent (201) 576-3475
al@aurora.UUCP (Al Globus) (05/29/85)
> > Getting stuck "motionless" in vacuum is another matter. But > if one got stuck there by pushing another mass away, won't > the astronaut and the mass meet again in one orbit? Not if the force is along the velocity vector, at least. If you push away a mass along the velocity vector one object will go into a higher orbit and the other into a lower orbit. If the force is not along the velocity vector things get complex.
al@aurora.UUCP (Al Globus) (05/31/85)
> > > > Getting stuck "motionless" in vacuum is another matter. But > > if one got stuck there by pushing another mass away, won't > > the astronaut and the mass meet again in one orbit? > > Not if the force is along the velocity vector, at least. If you > push away a mass along the velocity vector one object will go > into a higher orbit and the other into a lower orbit. If the > force is not along the velocity vector things get complex. Whoops! After exactly one orbit you will meet up again, and will every orbit until one party or the other is disturbed. Sorry ....
@S1-A.ARPA,@MIT-MC.ARPA:Ghenis.pasa@Xerox.ARPA (06/03/85)
From: Ghenis.pasa@Xerox.ARPA >>> >>> Getting stuck "motionless" in vacuum is another matter. But >>> if one got stuck there by pushing another mass away, won't >>> the astronaut and the mass meet again in one orbit? >> >> Not if the force is along the velocity vector, at least. If you >> push away a mass along the velocity vector one object will go >> into a higher orbit and the other into a lower orbit. If the >> force is not along the velocity vector things get complex. > >Whoops! After exactly one orbit you will meet up again, and will every >orbit until one party or the other is disturbed. Sorry .... Whoops! Both objects will continue to pass through the point of separation in each orbit, but they will not meet for a long time because having different orbits they will have different orbital periods, hence they won't return to that point AT THE SAME TIME after one orbit. Sorry ....