> It seems to me that the ISS could just use a trash compactor then shoot the
> packages into the atmosphere to burn up WITHOUT wasting the spacecraft,

Might be a good first-use verification of mass-driver technology.

Ive often wondered if one couldnt use a tether to lower the trash and then release. On release, the station would get a slight orbital boost, so itd be a win-win.

Regards,

Mike Combs

On Apr 16, 2012, at 7:48 AM, Combs, Mike wrote:

> > It seems to me that the ISS could just use a trash compactor then
> shoot the
> > packages into the atmosphere to burn up WITHOUT wasting the
> spacecraft,
>
The spacecraft is dumped because there's no good place to put it and
no good use to put it to in the immediate future. There are only a
couple of docking ports on the ISS. If you didn't get rid of the
Progress capsules you would, very quickly, not be able to dock with
the ISS. If you fly the Progress free it will run out of reboost fuel
very quickly and deorbit in some random place -- not good.
Furthermore, while waiting to deorbit it sucks up ground station
resources.

That's why they dump them quickly. Since they are going anyway,
putting the trash in them makes sense.

Al,
I couldn't find data for progress right away, but here's the stuff on the
ATV, which has cargo capacity far out doing progress. Each of these
spacecraft cost us $300,000,000.00, and carry 8 tons of cargo (that's a
lot).
With the ATV docked, the station crew enters the cargo section and removes
the payload. The ATV's liquid tanks are connected to the station's plumbing
and discharge their contents. The station crew manually releases air
components directly into the ISSs atmosphere. For up to six months, the
ATV, mostly in dormant mode, remains attached to the ISS with the hatch
remaining open. The crew then steadily fills the cargo section with the
station's waste. At intervals of 10 to 45 days, the ATVs thrusters are used
to boost the station's altitude.
Once its mission is accomplished, the ATV, filled with up to 6.5 tonnes of
waste, separates. Its thrusters move the spacecraft out of orbit (de-orbit)
and place it on a steep flight path to perform a controlled destructive
re-entry high above the Pacific Ocean.
So, the ATV sits on station for 6 months, doesn't look like it's crowding
out anyting else. And as for the lack of fuel, it would be a small thing to
bring up actual fuel stores (or perhaps some of that 'waste' hydrogen) and
provide enough fuel (it wouldn't take much-they're in space) to move the
spacecraft to where they might actually be a huge asset rather than a
garbage can. Just a couple of suggestions might be to move them where they
could hook up with one of the Bigelow inflatable habitats that are up there
or coming soon, or even out to one of the LaGrange Points for use with
construction or transport in that future hotspot. But, DON'T THROW AWAY
$300 MILLION SPACECRAFT THAT ARE ALREADY IN SPACE AND READY TO USE, IT JUST
DOESN'T MAKE SENSE!!!

From: Al Globus
Sent: Tuesday, April 17, 2012 12:49 AM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Dealing with ISS trash

On Apr 16, 2012, at 7:48 AM, Combs, Mike wrote:

> > It seems to me that the ISS could just use a trash compactor then
> shoot the
> > packages into the atmosphere to burn up WITHOUT wasting the
> spacecraft,
>
The spacecraft is dumped because there's no good place to put it and
no good use to put it to in the immediate future. There are only a
couple of docking ports on the ISS. If you didn't get rid of the
Progress capsules you would, very quickly, not be able to dock with
the ISS. If you fly the Progress free it will run out of reboost fuel
very quickly and deorbit in some random place -- not good.
Furthermore, while waiting to deorbit it sucks up ground station
resources.

That's why they dump them quickly. Since they are going anyway,
putting the trash in them makes sense.

The second intelligent statement in this thread.

John Wayne Smith

In a message dated 4/17/2012 4:43:02 A.M. Eastern Daylight Time,
victors@gvtc.com writes:

Al,
I couldn't find data for progress right away, but here's the stuff on the
ATV, which has cargo capacity far out doing progress. Each of these
spacecraft cost us $300,000,000.00, and carry 8 tons of cargo (that's a
lot).
With the ATV docked, the station crew enters the cargo section and removes
the payload. The ATV's liquid tanks are connected to the station's
plumbing
and discharge their contents. The station crew manually releases air
components directly into the ISSs atmosphere. For up to six months, the
ATV, mostly in dormant mode, remains attached to the ISS with the hatch
remaining open. The crew then steadily fills the cargo section with the
station's waste. At intervals of 10 to 45 days, the ATVs thrusters are
used
to boost the station's altitude.
Once its mission is accomplished, the ATV, filled with up to 6.5 tonnes of
waste, separates. Its thrusters move the spacecraft out of orbit
(de-orbit)
and place it on a steep flight path to perform a controlled destructive
re-entry high above the Pacific Ocean.
So, the ATV sits on station for 6 months, doesn't look like it's crowding
out anyting else. And as for the lack of fuel, it would be a small thing
to
bring up actual fuel stores (or perhaps some of that 'waste' hydrogen) and
provide enough fuel (it wouldn't take much-they're in space) to move the
spacecraft to where they might actually be a huge asset rather than a
garbage can. Just a couple of suggestions might be to move them where
they
could hook up with one of the Bigelow inflatable habitats that are up
there
or coming soon, or even out to one of the LaGrange Points for use with
construction or transport in that future hotspot. But, DON'T THROW AWAY
$300 MILLION SPACECRAFT THAT ARE ALREADY IN SPACE AND READY TO USE, IT
JUST
DOESN'T MAKE SENSE!!!

From: Al Globus
Sent: Tuesday, April 17, 2012 12:49 AM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Dealing with ISS trash

On Apr 16, 2012, at 7:48 AM, Combs, Mike wrote:

> > It seems to me that the ISS could just use a trash compactor then
> shoot the
> > packages into the atmosphere to burn up WITHOUT wasting the
> spacecraft,
>
The spacecraft is dumped because there's no good place to put it and
no good use to put it to in the immediate future. There are only a
couple of docking ports on the ISS. If you didn't get rid of the
Progress capsules you would, very quickly, not be able to dock with
the ISS. If you fly the Progress free it will run out of reboost fuel
very quickly and deorbit in some random place -- not good.
Furthermore, while waiting to deorbit it sucks up ground station
resources.

That's why they dump them quickly. Since they are going anyway,
putting the trash in them makes sense.

>
> Might be a good first-use verification of mass-driver technology.
>
> Ive often wondered if one couldnt use a tether to lower the trash
> and then release. On release, the station would get a slight orbital
> boost, so itd be a win-win.
>
> Regards,
>
> Mike Combs
>

Version: 2012.0.2127 / Virus Database: 2411/4941 - Release Date: 04/16/12

Well there are two options, either includes developing a mass launcher to dump the waste for extra lift. First you could put up a modest scaffolding outside the station to hold the excess progress modules until you lift a 6 sided dock module that could link with the ISS and allow the 5 extra modules to be linked there. Then when you build up 4 more progress modules, you'd have to send up another 6 sided and it would extend the first outward from the station.

Or you could redesign progress to have two hatches, one in front and one in back, so that with every docking of progress you add to the station. Not sure how long it would take or how expensive it would be to redesign progress or design a new 6 sided docking module.
Brooks

--- In spacesettlers@yahoogroups.com, "Victor Smith" wrote:

There are a number of other things that one can do. You can actually
recycle all of the trash or garbage. At least half of the people on this list
could figure it out and not break a sweat.
Address the subject. Don't dance around it like you are working for NASA.

John Wayne Smith

In a message dated 4/17/2012 10:38:20 A.M. Eastern Daylight Time,

Well there are two options, either includes developing a mass launcher to
dump the waste for extra lift. First you could put up a modest scaffolding
outside the station to hold the excess progress modules until you lift a 6
sided dock module that could link with the ISS and allow the 5 extra
modules to be linked there. Then when you build up 4 more progress modules,
you'd have to send up another 6 sided and it would extend the first outward
from the station.

Or you could redesign progress to have two hatches, one in front and one
in back, so that with every docking of progress you add to the station. Not
sure how long it would take or how expensive it would be to redesign
progress or design a new 6 sided docking module.
Brooks

--- In spacesettlers@yahoogroups.com, "Victor Smith" wrote:
>
> Al,
> I couldn't find data for progress right away, but here's the stuff on
the
> ATV, which has cargo capacity far out doing progress. Each of these
> spacecraft cost us $300,000,000.00, and carry 8 tons of cargo (that's a
> lot).
> With the ATV docked, the station crew enters the cargo section and
removes
> the payload. The ATV's liquid tanks are connected to the station's
plumbing
> and discharge their contents. The station crew manually releases air
> components directly into the ISSs atmosphere. For up to six months,
the
> ATV, mostly in dormant mode, remains attached to the ISS with the hatch
> remaining open. The crew then steadily fills the cargo section with the
> station's waste. At intervals of 10 to 45 days, the ATVs thrusters
are used
> to boost the station's altitude.
> Once its mission is accomplished, the ATV, filled with up to 6.5 tonnes
of
> waste, separates. Its thrusters move the spacecraft out of orbit
(de-orbit)
> and place it on a steep flight path to perform a controlled destructive
> re-entry high above the Pacific Ocean.
> So, the ATV sits on station for 6 months, doesn't look like it's
crowding
> out anyting else. And as for the lack of fuel, it would be a small
thing to
> bring up actual fuel stores (or perhaps some of that 'waste' hydrogen)
and
> provide enough fuel (it wouldn't take much-they're in space) to move the
> spacecraft to where they might actually be a huge asset rather than a
> garbage can. Just a couple of suggestions might be to move them where
they
> could hook up with one of the Bigelow inflatable habitats that are up
there
> or coming soon, or even out to one of the LaGrange Points for use with
> construction or transport in that future hotspot. But, DON'T THROW AWAY
> $300 MILLION SPACECRAFT THAT ARE ALREADY IN SPACE AND READY TO USE, IT
JUST
> DOESN'T MAKE SENSE!!!
>
> From: Al Globus
> Sent: Tuesday, April 17, 2012 12:49 AM
> To: spacesettlers@yahoogroups.com
> Subject: Re: [spacesettlers] Dealing with ISS trash
>
> On Apr 16, 2012, at 7:48 AM, Combs, Mike wrote:
>
> > > It seems to me that the ISS could just use a trash compactor then
> > shoot the
> > > packages into the atmosphere to burn up WITHOUT wasting the
> > spacecraft,
> >
> The spacecraft is dumped because there's no good place to put it and
> no good use to put it to in the immediate future. There are only a
> couple of docking ports on the ISS. If you didn't get rid of the
> Progress capsules you would, very quickly, not be able to dock with
> the ISS. If you fly the Progress free it will run out of reboost fuel
> very quickly and deorbit in some random place -- not good.
> Furthermore, while waiting to deorbit it sucks up ground station
> resources.
>
> That's why they dump them quickly. Since they are going anyway,
> putting the trash in them makes sense.
>
> > Might be a good first-use verification of mass-driver technology.
> >
> > Ive often wondered if one couldnt use a tether to lower the
trash
> > and then release. On release, the station would get a slight orbital
> > boost, so itd be a win-win.
> >
> >
> > Regards,
> >
> > Mike Combs
> >
> -----
04/16/12

Recycling all the trash that ISS produces would be much harder then the two proposals I laid out.
Brooks

--- In spacesettlers@yahoogroups.com, jwsmith42000@... wrote:

Brooks, I disagree with you 100%.
Statements like that are the reason why we are still discussing this.
I do not want to think hard. I do not want to work hard.
Let's just coast along and talk about it for the next 5000 Years.
That is all NASA will do for you.

John Wayne Smith.

In a message dated 4/17/2012 11:43:33 A.M. Eastern Daylight Time,
bhn1700@... writes:

Recycling all the trash that ISS produces would be much harder then the
two proposals I laid out.
Brooks

As far as I know, no one recycles 100% their trash, so the idea the ISS can easily decide to do it seems like wishful thinking. I want them to be smart and using what you have the best way you can is good policy.

In fact my proposals are recycling, you take what was trash and a very expensive trash can (progress module) and with a mass driver and a 6 sided module, convert them into station keeping fuel and liveable space. Sounds good to me!
Brooks

--- In spacesettlers@yahoogroups.com, jwsmith42000@... wrote:

On 4/16/12 11:49 PM, Al Globus wrote:

> The spacecraft is dumped because there's no good place to put it and
> no good use to put it to in the immediate future. There are only a
> couple of docking ports on the ISS. If you didn't get rid of the
> Progress capsules you would, very quickly, not be able to dock with
> the ISS. If you fly the Progress free it will run out of reboost fuel
> very quickly and deorbit in some random place -- not good.

Would this change if your capsule was reusable (Dragon for example)?
The station activities would be about the same (you could even fill it
with carefully-bagged trash), but instead of burning up, it would splash
down and be recovered.

Of course I wouldn't be surprised if recovering and refurbishing a
capsule is more expensive than just building another one, even if it
does seem wasteful. Fortunately, SpaceX is likely to be keenly focused
on the bottom line, so I imagine they'll do whichever makes sense.

While we have not hit 100% yet we are closing in on that figure. I think
that if you worked in that field you would be very surprised.

John Wayne Smith

In a message dated 4/17/2012 1:13:52 P.M. Eastern Daylight Time,
bhn1700@... writes:

As far as I know, no one recycles 100% their trash, so the idea the ISS
can easily decide to do it seems like wishful thinking. I want them to be
smart and using what you have the best way you can is good policy.

In fact my proposals are recycling, you take what was trash and a very
expensive trash can (progress module) and with a mass driver and a 6 sided
module, convert them into station keeping fuel and liveable space. Sounds
good to me!
Brooks

--- In spacesettlers@yahoogroups.com, jwsmith42000@... wrote:

brooks,
If you ferry up some fuel, the spacecraft can remove themselves to wherever you want them. As far as the waste goes, solid waste could be compacted, liquid could be exposed to low temp and frozen. Both result in solid packages. If these solid packages were placed in an airlock pointing away from the angle of flight and released while pressurized, it should slow the packages enough to put them in a decaying orbit where theyll eventually burn up (small packages so no worries for where).

From: brooksn
Sent: Tuesday, April 17, 2012 9:37 AM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Re: Dealing with ISS trash

Well there are two options, either includes developing a mass launcher to dump the waste for extra lift. First you could put up a modest scaffolding outside the station to hold the excess progress modules until you lift a 6 sided dock module that could link with the ISS and allow the 5 extra modules to be linked there. Then when you build up 4 more progress modules, you'd have to send up another 6 sided and it would extend the first outward from the station.

Or you could redesign progress to have two hatches, one in front and one in back, so that with every docking of progress you add to the station. Not sure how long it would take or how expensive it would be to redesign progress or design a new 6 sided docking module.
Brooks

--- In mailto:spacesettlers%40yahoogroups.com, "Victor Smith" wrote:

JW,
I agree. For instance, some tons of this Trash is supposedly wastewater. How, in space, is there such a thing as WASTE water. Water is ALWAYS recycled, either back into water, or into its component parts and into the air supply.

From: jwsmith42000@...
Sent: Tuesday, April 17, 2012 9:47 AM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Re: Dealing with ISS trash

There are a number of other things that one can do. You can actually
recycle all of the trash or garbage. At least half of the people on this list
could figure it out and not break a sweat.
Address the subject. Don't dance around it like you are working for NASA.

John Wayne Smith

In a message dated 4/17/2012 10:38:20 A.M. Eastern Daylight Time,

Well there are two options, either includes developing a mass launcher to
dump the waste for extra lift. First you could put up a modest scaffolding
outside the station to hold the excess progress modules until you lift a 6
sided dock module that could link with the ISS and allow the 5 extra
modules to be linked there. Then when you build up 4 more progress modules,
you'd have to send up another 6 sided and it would extend the first outward
from the station.

Or you could redesign progress to have two hatches, one in front and one
in back, so that with every docking of progress you add to the station. Not
sure how long it would take or how expensive it would be to redesign
progress or design a new 6 sided docking module.
Brooks

--- In mailto:spacesettlers%40yahoogroups.com, "Victor Smith" wrote:
>
> Al,
> I couldn't find data for progress right away, but here's the stuff on
the
> ATV, which has cargo capacity far out doing progress. Each of these
> spacecraft cost us $300,000,000.00, and carry 8 tons of cargo (that's a
> lot).
> With the ATV docked, the station crew enters the cargo section and
removes
> the payload. The ATV's liquid tanks are connected to the station's
plumbing
> and discharge their contents. The station crew manually releases air
> components directly into the ISSs atmosphere. For up to six months,
the
> ATV, mostly in dormant mode, remains attached to the ISS with the hatch
> remaining open. The crew then steadily fills the cargo section with the
> station's waste. At intervals of 10 to 45 days, the ATVs thrusters
are used
> to boost the station's altitude.
> Once its mission is accomplished, the ATV, filled with up to 6.5 tonnes
of
> waste, separates. Its thrusters move the spacecraft out of orbit
(de-orbit)
> and place it on a steep flight path to perform a controlled destructive
> re-entry high above the Pacific Ocean.
> So, the ATV sits on station for 6 months, doesn't look like it's
crowding
> out anyting else. And as for the lack of fuel, it would be a small
thing to
> bring up actual fuel stores (or perhaps some of that 'waste' hydrogen)
and
> provide enough fuel (it wouldn't take much-they're in space) to move the
> spacecraft to where they might actually be a huge asset rather than a
> garbage can. Just a couple of suggestions might be to move them where
they
> could hook up with one of the Bigelow inflatable habitats that are up
there
> or coming soon, or even out to one of the LaGrange Points for use with
> construction or transport in that future hotspot. But, DON'T THROW AWAY
> $300 MILLION SPACECRAFT THAT ARE ALREADY IN SPACE AND READY TO USE, IT
JUST
> DOESN'T MAKE SENSE!!!
>
> From: Al Globus
> Sent: Tuesday, April 17, 2012 12:49 AM
> To: mailto:spacesettlers%40yahoogroups.com
> Subject: Re: [spacesettlers] Dealing with ISS trash
>
> On Apr 16, 2012, at 7:48 AM, Combs, Mike wrote:
>
> > > It seems to me that the ISS could just use a trash compactor then
> > shoot the
> > > packages into the atmosphere to burn up WITHOUT wasting the
> > spacecraft,
> >
> The spacecraft is dumped because there's no good place to put it and
> no good use to put it to in the immediate future. There are only a
> couple of docking ports on the ISS. If you didn't get rid of the
> Progress capsules you would, very quickly, not be able to dock with
> the ISS. If you fly the Progress free it will run out of reboost fuel
> very quickly and deorbit in some random place -- not good.
> Furthermore, while waiting to deorbit it sucks up ground station
> resources.
>
> That's why they dump them quickly. Since they are going anyway,
> putting the trash in them makes sense.
>
> > Might be a good first-use verification of mass-driver technology.
> >
> > Ive often wondered if one couldnt use a tether to lower the
trash
> > and then release. On release, the station would get a slight orbital
> > boost, so itd be a win-win.
> >
> > Regards,
> >
> > Mike Combs
> >
> -----
04/16/12

brooks,
I can get behind the massdriver thing, except for the water. The ring thing, though is overdo. Its much simpler, easier and cheaper to just remove them from the equasion by moving them to locations where they become huge asset, even jumping off points for whole new superstructures and facilities rather than keeping them onstation where they represent nothing but an obstacle once their supplies have been off-loaded.

From: brooksn
Sent: Tuesday, April 17, 2012 12:13 PM
To: spacesettlers@...m
Subject: [spacesettlers] Re: Dealing with ISS trash

As far as I know, no one recycles 100% their trash, so the idea the ISS can easily decide to do it seems like wishful thinking. I want them to be smart and using what you have the best way you can is good policy.

In fact my proposals are recycling, you take what was trash and a very expensive trash can (progress module) and with a mass driver and a 6 sided module, convert them into station keeping fuel and liveable space. Sounds good to me!
Brooks

--- In mailto:spacesettlers%40yahoogroups.com, jwsmith42000@... wrote:

On Apr 17, 2012, at 7:37 AM, brooksn wrote:

> Well there are two options, either includes developing a mass
> launcher to dump the waste for extra lift.
>
Mass drivers accelerate very rapidly. That puts a lot of force on the
station. I suggest a little analysis of the structure before you
start putting loads on it. The pieces survived launch, so they have
to be fairly robust (except the solar arrays, which were launched
folded up). In it's full configuration the ISS experiences very small
loads and weight limits suggest that one design as light, and therefor
weak, as possible. The solar arrays are particularly vulnerable as
they are big and floppy.

You can approach this by calculating the load that the reboost engines
put on the structure. You know the ISS can handle that. Anything
bigger you need some analysis to see if it can work.

> First you could put up a modest scaffolding outside the station to
> hold the excess progress modules until you lift a 6 sided dock module
>
And what are you going to launch this module on? The US modules and
nodes were lifted by the space shuttle, which is no longer available.
Do you have an idea of how much this module will cost?

Welcome to systems engineering.

http://www.astrium.eads.net/en/articles/atv-2-iss-international-space-station-reboost.html

This article indicates that 1,000 Newtons is applied during the ATV orbital adjustments. Not sure if more has been done but that's a start. I also see no reason not to make the mass driver relatively small, with small mass objects being used for the driver, so as to keep forces and electrical requirements down.

Well currently the progress ships make it there, and soon the SpaceX ships may be replacing them. If the ships are too small, once converted to the occasional 6 sided hatch, to use effectively, you can reduce the the hatches to a front, back, and then 2 or 3 more hathes coming off the center. And if still too small, hopefully you can still add a front and back hatch and then still grow it outward. If some sections of the ISS allow, possibly you could even put a two sided between modules growing the ship internally as well.
Brooks

--- In spacesettlers@yahoogroups.com, Al Globus wrote:

On 18 April 2012 06:55, Al Globus wrote:

>
> On Apr 17, 2012, at 7:37 AM, brooksn wrote:
>
> > Well there are two options, either includes developing a mass
> > launcher to dump the waste for extra lift.
> >
> Mass drivers accelerate very rapidly.

No they don't.

> That puts a lot of force on the station.
>

You know better than that Al, it's an electric propulsion system, there's
not enough power for large forces.

--
-Ian Woollard

On 18 April 2012 14:18, Combs, Mike wrote:

> > Mass drivers accelerate very rapidly. That puts a lot of force on the
> > station. I suggest a little analysis of the structure before you
> > start putting loads on it.
>
> That might be why I've been thinking a bit about using a retractable
> tether. Although I imagine there would be a tiny bit of a jolt when the
> release of a trash load creates a wave which propagates up the tether to
> the Station. One might could engineer the dynamics of the take-up reel to
> minimize the effects of the jolt.
>

It would be easier and probably better to have a slowly spinning loop
hanging down, spinning flat in the plane of the orbit, and when you want to
discard something, just attach a bucket to it, and let it fall down the
loop until it falls off at the furthest point, pulling the loop around as
it does so. The jarring shouldn't be too bad, and you'll get a propulsive
tug from it all the way down due to Coriolis effect (since an orbit is a
rotating reference frame centered at the middle of the earth).

It *should* be fairly smooth although you'd want to vibrationally decouple
the loop from the station.

> Regards,
>
> Mike Combs
>

--
-Ian Woollard

On Apr 18, 2012, at 9:19 AM, Ian Woollard wrote:

> On 18 April 2012 06:55, Al Globus wrote:
>
> > On Apr 17, 2012, at 7:37 AM, brooksn wrote:
> >
> > > Well there are two options, either includes developing a mass
> > > launcher to dump the waste for extra lift.
> > >
> > Mass drivers accelerate very rapidly.
>
> No they don't.
>
Yes they do. O'Neill was able to get 100s of gs (or something on
that order) in a few meters with prototypes build in his lab. SEP,
which you refer to below, accelerate ions to 10s of thousands of m/s
>
> > That puts a lot of force on the station.
> >
> You know better than that Al, it's an electric propulsion system,
> there's
> not enough power for large forces.
>
A mass driver that throws trash is much different that a Solar
Electric Propulsion (SEP) system. SEPs, which are in use today,
accelerate ions to anywhere from 10,000-30,000 m/s. Ions have a lot
less mass than trash (many, many orders of magnitude) which is why the
total thrust is low.

On 18 April 2012 17:46, Al Globus wrote:

>
> On Apr 18, 2012, at 9:19 AM, Ian Woollard wrote:
>
> > On 18 April 2012 06:55, Al Globus wrote:
> >
> > > On Apr 17, 2012, at 7:37 AM, brooksn wrote:
> > >
> > > > Well there are two options, either includes developing a mass
> > > > launcher to dump the waste for extra lift.
> > > >
> > > Mass drivers accelerate very rapidly.
> >
> > No they don't.
> >
> Yes they do. O'Neill was able to get 100s of gs (or something on
> that order) in a few meters with prototypes build in his lab. SEP,
> which you refer to below, accelerate ions to 10s of thousands of m/s
>

Nope. You're still not getting it. That's the peak acceleration of the
*propellant*.

The gun is *much* heavier, and doesn't accelerate at anything like that
amount.

And the time averaged acceleration of the gun is far lower still. So you
just mount the gun on springs and dampers, or if you're really fancy you
can use magnets to transfer the forces.

--
-Ian Woollard

Well I'm far from an expert but I did some back of the envelope calculations. If you accelerate a 1 kg (about 2.2 lb) body to 1,000 m/s^2 you get 1,000 N of force. F = ma. If the station can take 1,000 N during orbit adjustments ISS 'should' be able to hand mass driver at these speeds and masses. (Assuming I didn't screw something up.) Also if the mass driver has many points along the rail that act to accelerate the mass, we might have 10 or 100 points that act, spreading the forces even more.

The real problems may be designing it, installing it, and processing current waste into shootable balls on station. Plus there's still the redesign of the progress/spacex capsule, or design of the new multiport capsule. Oh yeah, and convincing NASA.
Brooks

--- In spacesettlers@yahoogroups.com, Ian Woollard wrote: