ISS altitude maintenance/reboost plan?

This topic has come up in the past, but the question remains:

Is there somewhere in NASA a plan for maintaining the ISS orbital
altitude over the next decade or so?

The present trend is, literally, down:

http://www.heavens-above.com/issorbi... Height+in+km

According to past discussions, the Russian components have a lot of
reserve fuel that can be used to raise the altitude by a fair number of
tens of kilometers -- once. And the real crunch point won't come until
ISS has gotten another 50 or so kilometers lower. And maybe ATV will
come along as a tanker.

But is there actually a plan for such things happening, even if just
penciled in as a set of goals?

P.S.: And ISS is getting more massive, it's just added a large amount
of surface area, and the solar cycle is bottoming out and will be
headed up over the next several years. Planning would seem to be in
order.

wrote in message
ups.com...

This topic has come up in the past, but the question remains:

Is there somewhere in NASA a plan for maintaining the ISS orbital
altitude over the next decade or so?

The present trend is, literally, down:

http://www.heavens-above.com/issorbi... Height+in+km

According to past discussions, the Russian components have a lot of
reserve fuel that can be used to raise the altitude by a fair number of
tens of kilometers -- once. And the real crunch point won't come until
ISS has gotten another 50 or so kilometers lower. And maybe ATV will
come along as a tanker.

ATV will function both as a tanker and will be able to reboost ISS with its
own engines. Think of it as a Big Progress. ;-)

But is there actually a plan for such things happening, even if just
penciled in as a set of goals?

Good question since the US propulsion module was killed long ago and
wouldn't have been very useful after 2010 with the shuttle retirement since
the proposals for US propulsion all seemed to assume the shuttle would be
available for fuel delivery.

P.S.: And ISS is getting more massive, it's just added a large amount
of surface area, and the solar cycle is bottoming out and will be
headed up over the next several years. Planning would seem to be in
order.

Hopefully commercial resupply of ISS will be successful. At the very least
it could free up mass on Progress which could be replaced with more fuel. I
thought the last Progress that went to Mir had more fuel that would normally
be sent to Mir. Astronautix.com says that this Progress, Progress M1-5,
carried 2677 kg of fuel (Astronautix.com says a normal Progress M1 could
carry 1950 kg of fuel).

If commercial resupply falls through, CEV could likely be used for some
resupply and reboost of ISS.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

On Oct 30, 1:50 pm, " wrote:
But is there actually a plan for such things happening, even if just
penciled in as a set of goals?

From what I understand, the current low orbit is planned, because some
of the forthcoming assembly missions have very tight margins.

" wrote in
ups.com:

This topic has come up in the past, but the question remains:

Is there somewhere in NASA a plan for maintaining the ISS orbital
altitude over the next decade or so?

Yes.

P.S.: And ISS is getting more massive...

Check your understanding of physics. More mass results in *less* drag
deceleration, not more.

--
JRF

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check "Organization" (I am not assimilated) and
think one step ahead of IBM.

I think hop is right, this gradual orbital decline has been planned
to optimize payload performance in the next few flights...


"hop" wrote
From what I understand, the current low orbit is planned, because some
of the forthcoming assembly missions have very tight margins.

"Jim Oberg" wrote in news:UJG1h.33924
:

I think hop is right, this gradual orbital decline has been planned
to optimize payload performance in the next few flights...


"hop" wrote
From what I understand, the current low orbit is planned, because some
of the forthcoming assembly missions have very tight margins.


Right, it will "bottom out" with STS-117 in March, which has the lowest ISS
rendezvous altitude (181 n.mi.).


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
think one step ahead of IBM.

Jorge R. Frank wrote:

P.S.: And ISS is getting more massive...

Check your understanding of physics. More mass results in *less* drag
deceleration, not more.

Depends on how much (frontal) area comes along with the mass. In any
case, the actual point is that more mass does, no fooling, mean more
fuel is needed to make up a given decrease in altitude.

"Jorge R. Frank" wrote in message
...
Check your understanding of physics. More mass results in *less* drag
deceleration, not more.

And doesn't the total reboost total impulse (thrust times time, right?) you
need for a certain time period in orbit depend only on the drag force, which
depends on the frontal area of the station, not on the mass of the station?
In other words, two stations with different masses, but with the same drag
force (frontal areas) would need the same total reboost total impulse over
the same time in orbit, right?

So adding more modules to ISS in such a way as to increase the frontal area
will increase drag and will require an increase the amount of fuel needed to
maintain its orbit, right?

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

Jorge R. Frank wrote:

Right, it will "bottom out" with STS-117 in March, which has the lowest ISS
rendezvous altitude (181 n.mi.).

Will the post-completion altitude of ISS eventually be restored to what
it was pre-Columbia?

OBE, but of interest: Figure 4 in

http://www.spaceflight.esa.int/users...ion_prelim.pdf

I think there's some mislabeling.