James Webb telescope

1.5M miles. God help them if it needs a service mission.

http://news.bbc.co.uk/2/hi/americas/6645179.stm

Rich wrote:
1.5M miles. God help them if it needs a service mission.

They know that... So did the people who put Chandra, XMM-Newton,
WMAP, and Spitzer way beyond low Earth orbit as well. And IUE
before that - servicing has been a real possibility for only
one telescope, and that was as much political heritage as a purely
engineering decision.


Bill Keel

Isaac isolated the solar system from the rest of the Universe in
trying to force his terrestrial ballistics agenda into Keplerian
orbital geometry -

"Cor. 2. And since these stars are liable to no sensible parallax from
the annual motion of the earth, they can have no force, because of
their immense distance, to produce any sensible effect in our system.
Not to mention that the fixed stars, every where promiscuously
dispersed in the heavens, by their contrary actions destroy their
mutual actions, by Prop. LXX, Book I."
Newton

As the solar system has a galactic orbital motion,it stands to reason
that the influence of the solar system's gactic orbital motion in one
direction around the Milky Way axis affects heliocentric orbital
geometries as the forward galactic orbital motion of the Sun combined
with the heliocentric orbital motion of the Earth whichj spends 6
months traveling in the direction of galactic orbital motion and 6
months against that galactic orbital motion may,I repeat,may generate
Keplerian orbital geometries.

Of course you lock yourselves in the celestial sphere bubble of Newton
and the exotic offshoots and never get to consider the compound
orbital motions of the Earth.


On May 11, 5:52 pm, Sam Wormley wrote:
Rich wrote:
1.5M miles. God help them if it needs a service mission.

http://news.bbc.co.uk/2/hi/americas/6645179.stm

No spacecraft locate in the vicinity of L2 are intended
to be serviced. The either work or they don't.

Lagrange Points
http://scienceworld.wolfram.com/phys...ngePoints.html
http://en.wikipedia.org/wiki/Lagrange_points#Stability

The first three Lagrangian points are technically stable only in
the plane perpendicular to the line between the two bodies. This
can be seen most easily by considering the L1 point. A test mass
displaced perpendicularly from the central line would feel a force
pulling it back towards the equilibrium point. This is because the
lateral components of the two masses' gravity would add to produce
this force, whereas the components along the axis between them
would balance out. However, if an object located at the L1 point
drifted closer to one of the masses, the gravitational attraction
it felt from that mass would be greater, and it would be pulled
closer. (The pattern is very similar to that of tidal forces.)

Although the L1, L2, and L3 points are nominally unstable, it turns
out that it is possible to find stable periodic orbits around these
points, at least in the restricted three-body problem. These
perfectly periodic orbits, referred to as "halo" orbits, do not
exist in a full n-body dynamical system such as the solar system.
However, quasi-periodic (i.e. bounded but not precisely repeating)
orbits following Lissajous curve trajectories do exist in the
n-body system. These quasi-periodic Lissajous orbits are what all
Lagrangian point missions to date have used. Although they are not
perfectly stable, a relatively modest effort at station keeping can
allow a spacecraft to stay in a desired Lissajous orbit for an
extended period of time. It also turns out that, at least in the
case of Sun-Earth L1 missions, it is actually preferable to
place the spacecraft in a large amplitude (100,000-200,000 km)
Lissajous orbit instead of having it sit at the Lagrangian point,
because this keeps the spacecraft off the direct Sun-Earth
line and thereby reduces the impacts of solar interference on the
Earth-spacecraft communications links. Another interesting and
useful property of the collinear Lagrangian points and their
associated Lissajous orbits is that they serve as "gateways" to
control the chaotic trajectories of the Interplanetary Transport
Network.

On May 11, 10:30 am, Rich wrote:
1.5M miles. God help them if it needs a service mission.

http://news.bbc.co.uk/2/hi/americas/6645179.stm

Rich, NASA is also working on robotic repair satellites. These would
fly between observing and weather satellites making repairs, replacing
power supplies and upgrade systems. This is a pretty common sense idea
- one that you would have thought would have been pursed earlier in
the space program. - Canopus56

Hi,

At my last day job at Northrop Grumman, I was the lead optical
designer/analyst for the James Webb Space Telescope (NGST at the time)
working with on the proposal and later with the Telescope prime, Ball
Aerospace.

They are acutely aware of the fact that only the Enterprise NCC 1701D
will be able to service the telescope at its Lagrange point and (trust
me on this one) everything is being done so as to not repeat the
HUBBLE PIE eating episode which NASA experienced.

If they blow this, there will be very top level careers on the line at
a large number of organizations and it will be a joke told for
hundreds of years.

Jim Klein


Rich wrote:

1.5M miles. God help them if it needs a service mission.

http://news.bbc.co.uk/2/hi/americas/6645179.stm

James E. Klein


Engineering Calculations
http://www.ecalculations.com

Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows.
1-818-507-5706 (Voice and Fax)
1-818-823-4121

"KDP2, not quite easy enough for a Caveman to use" :-)

canopus56 wrote:

On May 11, 10:30 am, Rich wrote:
1.5M miles. God help them if it needs a service mission.

http://news.bbc.co.uk/2/hi/americas/6645179.stm

Rich, NASA is also working on robotic repair satellites. These would
fly between observing and weather satellites making repairs, replacing
power supplies and upgrade systems. This is a pretty common sense idea
- one that you would have thought would have been pursed earlier in
the space program. - Canopus56

Never underestimate the short sightedness at NASA.

Jim
James E. Klein


Engineering Calculations
http://www.ecalculations.com

Engineering Calculations is the home of
the KDP-2 Optical Design Program
for Windows.
1-818-507-5706 (Voice and Fax)
1-818-823-4121

"KDP2, not quite easy enough for a Caveman to use" :-)

"canopus56" wrote:

Rich, NASA is also working on robotic repair satellites. These would
fly between observing and weather satellites making repairs, replacing
power supplies and upgrade systems. This is a pretty common sense idea
- one that you would have thought would have been pursed earlier in
the space program. - Canopus56

NASA has long desired to have such capability, but the enabling technology
is only recently allowing it to finally happen. Witness ASTRO and NextSat,
doing their servicing thing right now:

http://science.nasa.gov/headlines/y2...ar_nohands.htm
http://www.darpa.mil/orbitalexpress/...n_updates.html
http://www.darpa.mil/orbitalexpress/on_orbit_pics.html

On May 11, 8:17 pm, Jim Klein wrote:
Hi,

At my last day job at Northrop Grumman, I was the lead optical
designer/analyst for the James Webb Space Telescope (NGST at the time)
working with on the proposal and later with the Telescope prime, Ball
Aerospace.

They are acutely aware of the fact that only the Enterprise NCC 1701D
will be able to service the telescope at its Lagrange point and (trust
me on this one) everything is being done so as to not repeat the
HUBBLE PIE eating episode which NASA experienced.

If they blow this, there will be very top level careers on the line at
a large number of organizations and it will be a joke told for
hundreds of years.


They'll just change their name, like the people who made the Hubble
mirror did, and they likely won't pay for the mistake.

On May 11, 6:17 pm, Jim Klein wrote:
At my last day job at Northrop Grumman, I was the lead optical
designer/analyst for the James Webb Space Telescope (NGST at the time)
working with on the proposal and later with the Telescope prime, Ball
Aerospace.

Jim, Thanks for the in-the-know insider view. We are all looking
forward to many years of great images from the Webb, as we have had
from the Hubble. Too bad there isn't enough of a window to re-
engineer the Webb to have exchangeable components that could be
robotically removed and replaced. - Kurt

On May 11, 12:52 pm, Sam Wormley wrote:
Rich wrote:
1.5M miles. God help them if it needs a service mission.

http://news.bbc.co.uk/2/hi/americas/6645179.stm

No spacecraft locate in the vicinity of L2 are intended
to be serviced. The either work or they don't.

Imagine then the original Hubble sitting out there...