Death Sentence for the Hubble?

Rodney Kelp wrote:
...the NGST will be many times better.

NGST = Next Generation Space Telescope.
In 2002 it was renamed to James Webb
Space Telescope (JWST).

It is a monolithic design not suitable
for repair or upgrade. If something goes
wrong it will become another piece of
space junk.

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

In article ,
Andrew Nowicki writes:
All satellites and space telescopes should
be modular and compatible with telerobots
so that they can be upgraded frequently
and repaired.

Umm, how did you reach that conclusion? I thought the HST experience
shows the opposite. How many "new Hubbles" could have been launched
for the price of the servicing capability?

Just to be clear: this comment refers to future missions, not what
should be done with the existing HST.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
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Andrew Nowicki wrote:
All satellites and space telescopes should
be modular and compatible with telerobots
so that they can be upgraded frequently
and repaired.

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

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

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.

On 12 Feb 2005 20:45:16 -0800, "MrPepper11" wrote:

New York Times
February 13, 2005

EDITORIAL
Death Sentence for the Hubble?



bla bla bla..

-JATO
http://jatobservatory.org

JATO jato wrote:
On 12 Feb 2005 20:45:16 -0800, "MrPepper11" wrote:


New York Times
February 13, 2005

EDITORIAL
Death Sentence for the Hubble?




bla bla bla..

-JATO
http://jatobservatory.org

Notice no discussion of the risks.

"Our heroic cosmanauts must undertand that the State demand sacrifices..."

Sorry, about that - wrong station.

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.

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).

The deaths are equivalent to ~12 million passenger miles of automotive
travel, or every member of the American Astronomical Society driving
2000 miles, or every U.S. amateur astronomer driving about a dozen
miles, or every person who has ever looked at a Hubble picture and
thought 'wow! that's cool' driving a few hundred meters.

Or to put it another way, it's equivalent to each of the seven
astronauts who decide that they are willing to risk a Shuttle flight to
fix Hubble doing so.

Now that the safety issue has been addressed (although not compared to
that of the dozens of planned trips to the ISS, with only a marginal
increase in safety per flight) let's go and fix it.

--
David M. Palmer (formerly @clark.net, @ematic.com)