I am not advocating de-orbiting ISS. But curious on technique.

Assuming a still fully functioning ISS with CMGs , functioning solar
panels and Zvezda's engines (are they still theoretically operational,
or formally disabled?)

I assume the first step would be using engines to lower its orbit to an
elliptocal with as low a perigee as possiuble , right?

Would the solar arrays then be used as a sail to slow it down further?
Or is it expected the de-orbit burn would bring it down low enopuigh
that the solar wings would detach within one or two perigees?

In terms of solar wings, would they be used to "steer" the station
further down, use then as wings to create lift to slow descent (but also
slow speed), or just have the solar wings perpenduciular to movement to
create the most air resistance?

or would engines be relied on for the full de-orbit in order to get
better control of where it re-enters and burn up?

From a burn up point of view, would a re-entry as whole better ebsure
full burn-up? I assume that by having a single item of mass X, it is
easier to predict where survivig pieces might reach ground?

Breaking up before re-entry interface would result in different
behaviours depending on density of piece re-entering and its shielding,
rig? Would this be significant, or still non brainer to ensure they all
fall into pacific?

Or owuld the goal be to focus on targeting the Pacific and having it
stay whole as long as possible to minimize possible footprint of any
remaining pieces falling in water?

In the case of Mir, the station had minimal control, abandonned and fell
down as a whole station. (and some reached the Pacific). But curious on
how a planned re-entry would be assuming it were still functional and
you could send flights up.

(Lets assume a real estate company buys the orbinal place (land) and
wants to demolish the ISS in order to build space condos).

Realistically though, is the fate of ISS same as that of Mir? Will be
abandonned, left unmanned and by the time its re-entry is imminent, too
late to do anything about it?

From what I've been reading, it's seems highly unlikely that the ISS
will be de-orbited even in this decade. I've heard basically that the
Russians are planning on abandoning their portions of the station
because simply the age of their modules being some of the oldest. Or
they may disconnect them and use them as a basis for a new Russian
station (I doubt that because of age). There is a lot of speculation that
it would not be that hard for New Space startups to come up with
replacements for the Russian modules that would give the ISS additional
life. Esp. if Starship comes on-line to help service it. So it remains to
be seen. On the other hand, should newer better cheaper hardware appear
on the horizon soon enough the ISS might well be decomissioned. Frankly
I think to bring it all down would be hugely wasteful. Perosnally, if it
were up to me, I'd attach a propulsion module to it and put it into L4
or L5 for use as parts in any construction project that might take place
there in the future. The beauty of these waypoints is that station
keeping is not needed as by then the ISS would be without power or
pressure.

Dave

JF Mezei presented the following explanation :
> I am not advocating de-orbiting ISS. But curious on technique.
>
> Assuming a still fully functioning ISS with CMGs , functioning solar
> panels and Zvezda's engines (are they still theoretically operational,
> or formally disabled?)
>
> I assume the first step would be using engines to lower its orbit to an
> elliptocal with as low a perigee as possiuble , right?
>
> Would the solar arrays then be used as a sail to slow it down further?
> Or is it expected the de-orbit burn would bring it down low enopuigh
> that the solar wings would detach within one or two perigees?
>
> In terms of solar wings, would they be used to "steer" the station
> further down, use then as wings to create lift to slow descent (but also
> slow speed), or just have the solar wings perpenduciular to movement to
> create the most air resistance?
>
> or would engines be relied on for the full de-orbit in order to get
> better control of where it re-enters and burn up?
>
>
> From a burn up point of view, would a re-entry as whole better ebsure
> full burn-up? I assume that by having a single item of mass X, it is
> easier to predict where survivig pieces might reach ground?
>
>
> Breaking up before re-entry interface would result in different
> behaviours depending on density of piece re-entering and its shielding,
> rig? Would this be significant, or still non brainer to ensure they all
> fall into pacific?
>
>
> Or owuld the goal be to focus on targeting the Pacific and having it
> stay whole as long as possible to minimize possible footprint of any
> remaining pieces falling in water?
>
>
> In the case of Mir, the station had minimal control, abandonned and fell
> down as a whole station. (and some reached the Pacific). But curious on
> how a planned re-entry would be assuming it were still functional and
> you could send flights up.
>
> (Lets assume a real estate company buys the orbinal place (land) and
> wants to demolish the ISS in order to build space condos).
>
> Realistically though, is the fate of ISS same as that of Mir? Will be
> abandonned, left unmanned and by the time its re-entry is imminent, too
> late to do anything about it?

Has Scott Manley answered any of your questions?

<URL:https://www.youtube.com/watch?v=U5lidnLtO7c>

/dps

--
Ieri, oggi, domani

On 2021-11-24 18:43, Snidely wrote:

> Has Scott Manley answered any of your questions?
>
> <URL:https://www.youtube.com/watch?v=U5lidnLtO7c>

It's why I asked my question here to have better understanding of
options (in partculat how much the solar wings could be used either as
air brakes or to direct station to lower altitude until they get blown
up by denser atmosphere).

Note to other poster: I don't want ISS to come down. And even the old
Russian modules, if separated, can act as early station modules that
provide early ECLSS and orbit keeping, docking port, airlock. Once rest
of station is built, then the old modules can be ditched.

JF Mezei explained :
> On 2021-11-24 18:43, Snidely wrote:
>
>> Has Scott Manley answered any of your questions?
>>
>> <URL:https://www.youtube.com/watch?v=U5lidnLtO7c>
>
> It's why I asked my question here to have better understanding of
> options (in partculat how much the solar wings could be used either as
> air brakes or to direct station to lower altitude until they get blown
> up by denser atmosphere).

Why would you think we have more knowledge than Scott Manley, who's at
least looked at some of the references?

I thought his explanation was pretty clear ... the solar arrays can be
used to start a protracted deorbit process, but attitude control
becomes a problem, and the point of reentry tending to the
uncontrolled. Most likely a Progress or two will be used to make a
controlled reentry.

I don't know if Cygnus could do a controlled de-orbit. I haven't come
across anything about what delta-V it can apply to the station, or how
much fuel it has. It's also at a less attractive port in terms
steering the ISS.

> Note to other poster: I don't want ISS to come down. And even the old
> Russian modules, if separated, can act as early station modules that
> provide early ECLSS and orbit keeping, docking port, airlock. Once rest
> of station is built, then the old modules can be ditched.

An "Abe Lincoln's Axe" scenario can go on for quite a while at ISS, but
the older modules are considered "fragile" in the sense of stresses
around the module connections and in terms of the machinery being worn,
if not worn out. I don't see even the cash-strapped Russians using the
older modules as a starting point for a new station; they've already
burned one up in the past few weeks, and that was, as WP notes, the
first permanent ISS module to be decommissioned.

(/Pirs/, 2001-09-14 to 2021-07-26)

/Prichal/, just launched, was originally intended to be temporary at
the ISS, waiting for other OPSEK components to be attached before being
becoming a separate station. With OPSEK abandoned, /Prichal/ is now
going to be permanent on ISS.

/dps

--
Who, me? And what lacuna?