Emergency Funding

>
> Energy systems need not also be solar. You can use
> nuclear fuel on the moon just as easily as solar.
>
> If protestors allow you to launch. I don't think a
> full-up radio telescope
> could be powered by the kind of radio isotope
> generator which powered
> Cassini (and even that attracted a lot of protest).
> I think it's going to
> need a full-up nuclear reactor. I know there's a
> NASA push in this
> direction, but it may be a non-starter, politically
> (especially after our
> second Shuttle disaster).
>

I am unsure if we are thinking the same thing here
then. My idea of a lunar radio observatory is more
ala VLA then arecibo. Each dish exists with its own
independent power. For this model, RI generator would
be sufficient.

> I
> would see the fact that the sun is blocked 50% of
> the
> time as an advantage not disadvantage.
>
> Then you're not viewing things from the High
> Frontier perspective.
>
Not sure on what this comment is suppose to imply.
There is a large difference between human colony and
an automated scientific outpost. I don't recall
anywhere in O'neil's writings that ALL things had to
be off planet.

For this scientific study, not seeing the Sun is
advantages as there will not be noise from it. This
has nothing to do with a high frontier perspective.
>
> The delta v I have not crunched but if I remember
> correctly, there is not a very significant delta v
> between the Moon and HEO.
>
> Well, it depends on how you define "significant".
> Compared to the delta V
> to just get off the Earth in the first place, it's
> pretty small (and that's
> always the problem, isn't it?). TLI injection may
> actually be smaller than
> injection to and circularization at HEO, but don't
> forget we have to add in
> braking thrust for capture into LLO, descent, and
> soft-landing.
>
As per my earlier comments, aero braking is unnecesary
if you use a landing similiar to that which pathfinder
used.
>
> I am not assuming we are in an era with routine
> access. A lunar radio observatory can be done with
> today's technologies and infrastructure. All that
> is
> needed is a couple of relay satellites and then you
> can add to the interferometer on the far side as you
> see fit too.
>
> I guess we're envisioning different things. I was
> thinking in terms of an
> Arecibo-class radio telescope.
>
An arecibo-class radio telescope I do not think is
practical. Most astronomers want to look at the very
low frequencies which you cannot see on Earth (10-10^4
m wavelengths). For this to happen, we are talking
about 100 km size area. Now Drake's original idea
called for a single dish made by lining a whole crater
with wire, the more modern approach to this is to use
an interferometer.
>
> But again, by how much? What's the comparison
> between the delta with and
> without shielding, and the delta between the two
> delta-Vs involved? Can a
> millimeter of aluminum shield out radio waves, and
> if so, what more would be
> required for the baffle?
>
I am not in a position to argue these points at this
time. I am way to unfamilar with the HEO concept to
even begin to estimate these costs and weights. The
biggest concern here is that this is a recurring cost.

We can just say if you'd like for arguments sake that
its only an increase of $20 million total for
everything (this includes material, testing and launch
costs). Then lets say you want to make the 10 of
these, thats an added cost of 200 million that would
not be necessary if you were to use the moon.

The big kicker would be if the weight of the shielding
required an even bigger rocket. This could boost up
the price of the launch dramatically. But again,
without real numbers, this discussion is moot.

At this point, all we can say is that the weight would
be higher for HEO.

The only other issue I have with the shielding concept
is the amount of station keeping required to make it
effective. This can be reduced to some extent using
ion thrusters but again, I would need to see a more
developed HEO plan to see the total affect.

Ryan