Some thoughts on Mining Asteroids vs the Moon

> > I would forgo heavy gravitation wells also and I would go Sun-wards
> > because of the ample energy supply available according to the inverse
>
> Frank, the Sun has a gravity well much deeper than the Moon.

Yes, but I would not try landing on the Sun as you would do on the Moon
(and having to take off again).
Landing and taking off again would happen on an asteroid which is in an
orbit
around Sun. This orbit of the asteroid has to be matched.
Two small craft have done asteroid-landings already, NEAR and Hayabusa were
Hayabusa landed and took off two times in one mission.

>
> You are talking going to 0.5AU, I can provide the delta-vee numbers
> for you but I need some more details.

I think, you concentrate too much on delta-V. It is not about delta-V
only but acceleration
of large, heavy craft and small lightweight craft which doesn't have to
land on the Moon
(and would not be able to do so) with a propulsion system, which can
deliver a lot delta-V
be it ion-propulsion or solar sail propulsion.

>
> Are you planning to go into a circular orbit around the sun at 0.5 AU?
>
> Or are you looking at an elliptic orbit, aphelion 1AU, perihelio 0.5 AU?
>
> Please clarify, as it makes a big difference.

So, why not doing the calculation for both?
We would start with the circle. You are the orbit specialist, I admit,
that I am not and am just reckoning
that others would find the best way/orbit.

Say we would set out 6 communication satellites with the
SEP-Solar-Sailcraft around Sun in a
circular orbit, at 0.33 AU 60 grade away of each other and 6 satellites
using another carrier ship
at 0.66 AU from Sun.
Would you think, that would be impossible to do with a carrier-ship
which reaches the circular
orbit with ion propulsion (maybe a strong launcher could assist the
injection phase)
and sets out the sattellites using solar sail propulsion?

The carrier ships would have to reach the round orbit, one sattellite
would undock,
than the carrier ship has to accelerate or decelerate until a return to
the same orbit,
only 60 grade behind or in front of the first sattelite is possible.
Then the second sattelites undocks and so on, until we have a round
communication satellite circle around Sun.

Now we would look for the aphelion/perihelion orbit which has to match
the asteroid orbits,
I already mentioned.
> Some of the athens which can be found at
> http://cfa-www.harvard.edu/iau/lists/Atens.html
> http://cfa-www.harvard.edu/iau/lists/Atens.html>
> were p=Perihelion distance (in AU), Q = Aphelion distance (in AU).
>
> 2006 US216 p 0.278 Q 0.995
> 2006 KZ39 p 0.292 Q 0.939
> 2004 XZ130 p 0.337 Q 0.898
> 2006 WE4 p 0.641 Q 0.928

Just take one of them which seems to fit best in your eyes.

In this context I would like to point to the spacesailing website were
you can find under "publications"
the abstract which is quoted underneath:

>
> Solar sailcraft are due to their high DV-capability especially capable
> to perform multiple rendezvous and sample return missions to
> near-Earth objects. Even with moderate-performance solar sails of the
> first generation, challenging scientific missions are feasible at
> relatively low cost. Within this paper, it will be shown that a 300
> kg-spacecraft (including a lander and a sample return capsule),
> propelled by a (70 m)^2 solar sail with an additional mass of about
> 110 kg (specific weight 23 g/m^2 ), is capable to return a sample from
> a near-Earth asteroid to Earth within 10 years from launch. In another
> scenario, a solar sail of the same size and weight is able to propel a
> 75 kg-spacecraft to rendezvous three near-Earth asteroids subsequently
> within 7.6 years from launch (with about 200 days of operations at
> each asteroid). A larger solar sail of about (140 m)^2 would even be
> capable to transport a spacecraft that returns samples from the three
> near-Earth asteroids to Earth within about 10 years from launch.
>

Regards

Frank