Death Sentence for the Hubble?

Charles Buckley wrote in
:

Jorge R. Frank wrote:
Charles Buckley wrote in
:


David M. Palmer wrote:

In article , Max Beerbohm
wrote:




Seriously, if you are going to say that there is no reason not to
do a Hubble visit, you need to address the safety issue - as some
on this group have done.

The article above is poorly researched because of this.


The expected risk cost is ~0.1 lives and 0.015 shuttles (assuming a
1/70 chance of disaster with each shuttle mission not to ISS).


Recalculate for 1/50 That is the current safety rating.


According to whom? Cite your sources, please.


Demonstrated safety.

Demonstrated safety is as I posted below. It's 1:56.5 if you count *all*
shuttle flights, 1:88 if you only consider post-51L (since the failure mode
in that accident has since been eliminated).

They have not yet established that they can
calculate the the safety rate accurately.


At *worst*, it's 1/56.5 (+ post-CAIB safety improvements).

*Reasonably*, it's 1/88, (+ post-CAIB safety improvements).

Again, *cite* your sources, if you have any.




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

In article ,
(Henry Spencer) wrote:

There was a decision, very early in the design process of NGST/JWST, that
all the interesting/fun astronomy was going to be happening in the IR, and
so there was no need for UV and little need for visible wavelengths.

This does have design implications: the longer wavelengths mean more
relaxed optical requirements, easier to meet with deployable mirrors and
such. (This is also why adaptive-optics systems on Earth-based telescopes
mostly work in the IR at present.) In other words, if you're willing to
build a telescope that's IR-only, you can make it rather bigger with the
same technology... and that means more light-gathering power and better
ability to study very faint, very distant objects.

So, it wasn't a grossly unreasonable tradeoff; it had important virtues.
It may have been the wrong decision but it wasn't stupid.

But there *are* astronomers who do think it was the wrong decision.

This makes the Hubble Origins Probe more appealing as an alternative to
an HST repair mission: http://www.pha.jhu.edu/hop/

Andrew Nowicki wrote:

All satellites and space telescopes should
be modular and compatible with telerobots
so that they can be upgraded frequently
and repaired.

Christopher M. Jones" wrote:

If we require compatability with non-existent entities
then we might as well require that the device work by
magic, or be compatable with leprechaun-based maintenance
work or what-have-you.

Dextre already exists.

Besides which, maintenance compatability does not come
cheap, nor does the maintenance, with or without robots.

Most compatibility issues are just common sense rules.
They are described in:

AIAA Guide for Berthing/Docking/Grasping Interfaces for
Serviceable Spacecraft, 1992, AIAA, ISBN 1-56347-052-7.

AIAA Guide for Utility Connector Interfaces for Serviceable
Spacecraft, 1995, AIAA, ISBN 1-56347-134-5.

Dextre cannot handle very small bolts/screws so all the
connectors have to be rather large. This is not a big
issue because we are talking about modular design --
all Dextre has to do is to replace modules. Another
little problem is that modular design takes up more
space that the monolithic, throwaway design. This means
that the modular satellite/telescope is longer than
the monolithic one.

Realistically, you save very little, if anything,
from maintenance compatability. Indeed, sometimes you
lose because you spend money fixing up obsolete hardware
rather than putting the effort into completely new systems.
For the money we've spent on HST upgrades already we
could have had another HST-class telescope on orbit
*right now* (maybe more than one), and it wouldn't be
15 years old with bits that use 20+ year old technology.

Using the shuttle to service the HST and ISS did not
make economic sense, but it "proved" that the shuttle
was not a complete waste of money. Dextre is much
cheaper because it can service a plethora of satellites
and telescopes 24 hours a day, 365 days a year. It
does not ask for a raise, does not rape female astronauts,
and does not need expensive funeral when it dies while
on duty. When all the satellites have been fixed Dextre
will be removing space junk.

PS. Space cadets hate Dextre because it seems to replace
heroic astronauts conquering the universe. Actually, the
opposite is true. Dextre and its ilk are necessary to
build the infrastructure that will make outer space
safe and affordable for us. People belong to orbital
greenhouses, telerobots belong to dangerous environments.

Andrew Nowicki wrote:

All satellites and space telescopes should
be modular and compatible with telerobots
so that they can be upgraded frequently
and repaired.

Christopher M. Jones" wrote:

If we require compatability with non-existent entities
then we might as well require that the device work by
magic, or be compatable with leprechaun-based maintenance
work or what-have-you.

Dextre already exists.

Besides which, maintenance compatability does not come
cheap, nor does the maintenance, with or without robots.

Most compatibility issues are just common sense rules.
They are described in:

AIAA Guide for Berthing/Docking/Grasping Interfaces for
Serviceable Spacecraft, 1992, AIAA, ISBN 1-56347-052-7.

AIAA Guide for Utility Connector Interfaces for Serviceable
Spacecraft, 1995, AIAA, ISBN 1-56347-134-5.

Dextre cannot handle very small bolts/screws so all the
connectors have to be rather large. This is not a big
issue because we are talking about modular design --
all Dextre has to do is to replace modules. Another
little problem is that modular design takes up more
space that the monolithic, throwaway design. This means
that the modular satellite/telescope is longer than
the monolithic one.

Realistically, you save very little, if anything,
from maintenance compatability. Indeed, sometimes you
lose because you spend money fixing up obsolete hardware
rather than putting the effort into completely new systems.
For the money we've spent on HST upgrades already we
could have had another HST-class telescope on orbit
*right now* (maybe more than one), and it wouldn't be
15 years old with bits that use 20+ year old technology.

Using the shuttle to service the HST and ISS did not
make economic sense, but it "proved" that the shuttle
was not a complete waste of money. Dextre is much
cheaper because it can service a plethora of satellites
and telescopes 24 hours a day, 365 days a year. It
does not ask for a raise, does not rape female astronauts,
and does not need expensive funeral when it dies while
on duty. When all the satellites have been fixed Dextre
will be removing space junk.

PS. Space cadets hate Dextre because it seems to replace
heroic astronauts conquering the universe. Actually, the
opposite is true. Dextre and its ilk are necessary to
build the infrastructure that will make outer space
safe and affordable for us. People belong in orbital
greenhouses, telerobots belong in dangerous environments.

Andrew Nowicki wrote:

:All satellites and space telescopes should
:be modular and compatible with telerobots
:so that they can be upgraded frequently
:and repaired.

Given current costs to orbit it is cheaper to throw them away and
launch new.

--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney

In article ,
richard schumacher wrote:
But there *are* astronomers who do think it was the wrong decision.

This makes the Hubble Origins Probe more appealing as an alternative to
an HST repair mission: http://www.pha.jhu.edu/hop/

It's an interesting concept... but it's far from clear that it's
bureaucratically feasible to treat it as an alternative to a repair
mission. The natural inclination is to treat it as a new telescope
proposal, something that would need to be thought about for years and
probably run through a competition against other concepts to decide
whether it's worth doing, after which it would take another 5-10 years
before it would actually fly.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Andrew Nowicki wrote:

All satellites and space telescopes should
be modular and compatible with telerobots
so that they can be upgraded frequently
and repaired.

Fred J. McCall" wrote:

Given current costs to orbit it is cheaper to
throw them away and launch new.

Suppose that a satellite has the mass of 10 tons
and is made of 100 modules of equal mass. One of
the modules is made of 3 gyroscopes. Two years
after launch one of the gyros failed, but the
remaining two gyros still work, keeping the
satellite alive. A rescue mission launched 10
repair modules for 10 different satellites and
1 ton of ion thruster fuel. Dextre telerobot
picked up the repair modules and the fuel,
replaced the bad modules and transported the
bad modules to the ISS where astronauts took
them apart and managed to repair some of them.

The gyro repair module has the mass of 100 kg.
The amount of fuel to reach the damaged satellite
is probably on the same order of magnitude: 100 kg.
The total mass launched to orbit is 200 kg.
Dextre's mass is 1662 kg. You claim that the
total cost of making and launching the 10 ton
satellite is lower than the cost of making and
launching the 200 kg repair package.

Christopher M. Jones ) wrote:
: Rodney Kelp wrote:
: If they don't make the NGST better, higher quality, and more capable what's
: the point? Is there no progress any more?

: It will almost certainly be better, just not in the same areas
: where HST currently operates.

....which makes a case for keeping HST flying as long as possible.

Eric

Charles Buckley ) wrote:
: Eric Chomko wrote:
: Charles Buckley ) wrote:
: : David M. Palmer wrote:
: : In article , Max Beerbohm
: : wrote:
: :
: :
: :
: : Seriously, if you are going to say that there is no reason not to do a
: : Hubble visit, you need to address the safety issue - as some on this
: : group have done.
: :
: : The article above is poorly researched because of this.
: :
: :
: : The expected risk cost is ~0.1 lives and 0.015 shuttles (assuming a
: : 1/70 chance of disaster with each shuttle mission not to ISS).
: :
:
: : Recalculate for 1/50 That is the current safety rating.
:
:
: : It's not a safety issue. It is quite a bit of a project management
: : issue. The 2007 launch to Hubble would be right in the middle of
: : ISS flights. They would have to take a shuttle offline and do
: : a one-off flight to another destination. If they go with a
: : safety net of a spare shuttle, then you have created a gap of
: : a couple months when ISS construction and processing is interrupted.
:
: So ISS will get completed two months early and THAT is why Hubble can't
: be serviced? Two months? Real leadership would complete ISS and fix the
: Hubble. Partisan BS has Texas getting its project done whereas the ongoing
: Maryland project can go to hell!
:

: Generally, sudden halts in construction projects are bad. They can
: sometimes allow things backlogged to catch up, but that is not the case
: here. They have the parts and are ready to roll. Arbitrarily stopping
: construction to do a sideline task in a life extension program on
: something that has already been extended is not really something that
: makes a large amount of sense, or even a small amount. Shuttle is there
: for ISS now. Nothing else.

Right, and that is a political decision. HST was designed to be repaired
by the shuttle. The decision to not fix it now is politcal in favor of
ISS. Where is each mission based out of? Maryland - blue state. Texas -
red state. I'll let you guess which one is which.

Eric

Andrew Nowicki wrote:
Andrew Nowicki wrote:

All satellites and space telescopes should
be modular and compatible with telerobots
so that they can be upgraded frequently
and repaired.

Christopher M. Jones" wrote:

If we require compatability with non-existent entities
then we might as well require that the device work by
magic, or be compatable with leprechaun-based maintenance
work or what-have-you.

Dextre already exists.

Certainly. As does the tele-robotic, on orbit, remote
servicing spacecraft bus, which contains various
automated and remote controlled systems which allow it
to rendezvous with properly designed spacecraft, then
capture and berth them, then perform maintenance on
them, including replacing sub-systems such as gyros
or instrumentation, then seal them back up in a
configuration suitable for continued operation of the
spacecraft in question. More so, all these systems
are backed by robust ground operations procedures, and
both ground and flight software and simulations.

Oh. Wait. Now that I think about it, none of that
actually, you know, *exists*. Worse yet, there aren't
even any standards or detailed requirements describing
what such a system would or *should* look like. Indeed
there is no documentation anywhere on what "compatible
with telerobots" would entail, other than educated
guesses. As such, requiring that sort of
"compatability" is bound to border on a useless waste of
effort even in the best of circumstances.