the AstroHab system is composed of modular forms,
filled with local regolith, so it has a 2 feet
radiation built-in shield.
The entire concept behind it is to utilize 99% local
resources abd bring from Earth only lightweigh
stackable carbon fiber reinforced plastic forms to be
manually assembled b the crew on any estraterrestrial
body, without the need of heavy construction
equipment.
By combining a solar sail system for populsion(other
could be chemical and nuclear rockets or mass drivers)
but solar seems better, asteroid for resources
astrohab for equipment we could have a completely free
transportation system from Earth to any other ocation.
Second and more important step would be a earth to LEo
inexpensive 100$\Kg transportation system, that I
foresee composed of a two stage to orbit entirely
reusable hotol from comercial airport vehicle, with an
unmanned booster and a manned orbiter that will both
return to the airport of origin.
Third , together with AstroHab, which is a land based
station system, an inexpensive space based system,
maybe utilizing the shuttle booster tanks or
inflatable modules and forming a modular space station
with artificial gravity.
--- Frank nd@... ha scritto:
I took a look at that link.
I think it is a long way until we can place such
buildings onto Mars
and asteroids.
We dont even have the ability to get humans out of
Earths radiation
shield without subjecting them to death.
I think that will not change for a long time to go.
But we could be able in a very shorter time frame to
send out robotic
space crafts and bring back asteroidal ore to Low
Earth orbit.
>maybe we can get the best of two worlds with the
>following consideratiions:
>thereason I propose a deflected asteroid as spaceship
>on a cycler trajectory is due to one factor: asteroid
>have resources that can be utilized in space, solar
>sails don't.
Solar sails have a very important resource, constant
thrust through
Suns light pressure. That means free transportation.
They also can carry large power producing solar arrays
(at least in my
design). That means free energy.
But I agree, asteroidal recourses could be one of the
main reasons to
get them out into space.
>But solar sails as you proposed, with the right
>modifications could be the best propulsion system for
>small asteroids, even the 10\20\30000tons which would
>be big enough to supply what necessary.
The sail I propose would deliver up to about 36 N of
constant thrust
(that is 3.6 kg every second). But it is not only
about
moving 10 000 000 kg with that 3.6 kg constant thrust.
You have to overcome the inertia of that asteroid too.
I am not sure if that is possible in a reasonable time
frame.
>The asteroid would be equipped with the astrohab
>system, see the link above, and would work as a hotel
>plus life support production facility.
>On a cycler orbit between earth, the moon , mars or
>other locations this could be the most affordable
>solution with existing technology.
Sorry, but I think we just dont have the technology
now to put humans
into unshielded space because of radiation.
>I don't foreee asteroid mining to bring the material
>back to earth.
>We have all the needed materials here already at a
>fraction of the cost compared to space produced
ones.,
If you take the costs for howling 1 kg into space of
10000 $ a 100 ton
payload of water ice could be worth 1 billion bucks
when in Low Earth
Orbit.
The first spacecraft doing such a mission would also
make a lot of
profit out of television and publishing rights.
The two billion for the first mission could come in
with that mission
only, afterwards the sail craft gets off to the next
mission and
starts to earn profits.
Frank
Yo, Frank, what do you mean, getting humans outside
earths radiation shield and death??? If memory serves
me corectly, we put a few guys on the moon, and that's
considerably beyond earths magnetic shield, a shield
which we could easily emulate.
at making survival decisions. Tend to fall in holes
and such. Teleoperated bots in an industrial
environment would really only be precticable in NEO.
Even at GEOSYNC, the round trip time delay of .25
secs. is long enough to allow for errors in motion to
destroy your manufactured products or the Bots.
Still, bringing asteroids into NEO is a cool idea, as
long as you have perfect control of the orbitals. One
slight error, and India might end up a big hole in the
ground,,,Not very good Public Relations for the
orbital industries.
Gary 7>
All Apollo landings with humans aboard were at the time of the Full Moon. At this time the solar wind blows the past Earth, but Earth shields the Moon. So no, the lunar astronauts were not really outside the Earth's protective magnetic shield. This time was not selected from this knowledge, but for the best lighting on the lunar surface, but it did protect the astronauts from solar-proton radiation.
Behalf Of GARY ANSORGE
Yo, Frank, what do you mean, getting humans outside
earths radiation shield and death??? If memory serves
me corectly, we put a few guys on the moon, and that's
considerably beyond earths magnetic shield, a shield
which we could easily emulate.
Robots are cool. Unfortunately, they;'re not very good
at making survival decisions. Tend to fall in holes
and such. Teleoperated bots in an industrial
environment would really only be precticable in NEO.
Even at GEOSYNC, the round trip time delay of .25
secs. is long enough to allow for errors in motion to
destroy your manufactured products or the Bots.
Still, bringing asteroids into NEO is a cool idea, as
long as you have perfect control of the orbitals. One
slight error, and India might end up a big hole in the
ground,,,Not very good Public Relations for the
orbital industries.
Gary 7>
> All Apollo landings with humans aboard were at the time of the Full
> Moon. At this time the solar wind blows the past Earth, but Earth shields
> the Moon. So no, the lunar astronauts were not really outside the Earth's
> protective magnetic shield. This time was not selected from this knowledge,
> but for the best lighting on the lunar surface, but it did protect the
> astronauts from solar-proton radiation.
the solar wind was protecting the lunar astronauts against the sun's
radiation, even though the Earth is shown in several moon-based photos
as being close to the horizon, nowhere near the Sun?
http://tinyurl.com/de6nk
http://tinyurl.com/awvq9
Given that the Earth is nowhere near "new earth", which is the phase
you would see when the Earth is interposed between the Sun and the
Moon, how can this POSSIBLY be true?
The geometry is that at a full Moon (as observed on Earth) the Sun is on the opposite side of the Earth as the Sun, so at that time the Earth's magnetic field shields the Moon from the solar wind. At the time of the new Moon if one were on the lunar surface one would be exposed to much more radiation, and during solar proton events, one would need to be in a radiation shelter or it could be lethal. JSH
> All Apollo landings with humans aboard were at the time of the Full
> Moon. At this time the solar wind blows the past Earth, but Earth shields
> the Moon. So no, the lunar astronauts were not really outside the Earth's
> protective magnetic shield. This time was not selected from this knowledge,
> but for the best lighting on the lunar surface, but it did protect the
> astronauts from solar-proton radiation.
Okay, so what you're saying, is that the Earth's magnetic "wake" in
the solar wind was protecting the lunar astronauts against the sun's
radiation, even though the Earth is shown in several moon-based photos
as being close to the horizon, nowhere near the Sun?
http://tinyurl.com/de6nk
http://tinyurl.com/awvq9
Given that the Earth is nowhere near "new earth", which is the phase
you would see when the Earth is interposed between the Sun and the
Moon, how can this POSSIBLY be true?
>
>Yo, Frank, what do you mean, getting humans outside
>earths radiation shield and death??? If memory serves
>me corectly, we put a few guys on the moon, and that's
>considerably beyond earths magnetic shield, a shield
>which we could easily emulate.
you might take a look onto this link
http://www.space.com/scienceastronomy/mars_dangers_040120.html
or search for radiation+in+space .
You will see that the Moon is not the save heaven you think and that
we also have cosmic radiation which does not originate of the Sun.
>
>Robots are cool. Unfortunately, they;'re not very good
>at making survival decisions. Tend to fall in holes
>and such. Teleoperated bots in an industrial
>environment would really only be precticable in NEO.
We already have robots working on Mars under Mars gravity.
On asteroids you have very low gravity, so you could get away with
very low thrust to operate a craft which hovers above ground and
touches down to collect samples only.
When you bump into the asteroid with the lander, it might be that
doing it would do about the same as bumping with an auto scooter into
the side bumpers - that would be - nothing serious.
Here is an excerpt of this article at Wikipedia
http://en.wikipedia.org/wiki/Near_Earth_Asteroid_Rendezvous
about the soft landing of a space probe which landed on an asteroid
without being constructed for that purpose and without being harmed.
"The spacecraft then made a slow controlled descent to the surface of
Eros ending with a touchdown just to the south of the saddle-shaped
feature Himeros on February 12, 2001 at approximately 20:01 UT (3:01
p.m. EST). To the surprise of the controllers, the spacecraft was
undamaged and operational after the landing (thus becoming the first
spacecraft to soft-land on an asteroid)."
We will see more about asteroid landing and material extraction this
summer with the Japanese Ion driven spacecraft and lander Hayabusa
http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/index.shtml
"HAYABUSA will arrive at the asteroid summer of 2005. While staying
nearby it for about 5 months, it will make scientific observation and
collect samples from the asteroids surface. After that, it will leave
the asteroid and return to the earth summer of 2007."
I hope and bet all will go well with Hayabusa but cant close out your
danger scenario. We will see.
>Even at GEOSYNC, the round trip time delay of .25
>secs. is long enough to allow for errors in motion to
>destroy your manufactured products or the Bots.
It is not about making decisions in seconds, the thrust of those ion
drives is just so low (70 mN or less) that the lander can afford to
accelerate against ground without getting harmed when it hovers a few
meters above it and accelerates then.
The tele operators would have enough time to decide the next steps of
the lander.
>Still, bringing asteroids into NEO is a cool idea, as
>long as you have perfect control of the orbitals. One
>slight error, and India might end up a big hole in the
>ground,,,Not very good Public Relations for the
>orbital industries.
That was not my idea. I would prefer to send a solar sail mothership
with landers to extract asteroidal ore and bring it back to a space
station.
Frank
www.solar-thruster-sailor.info
For the first solar sail design of a carrier ship with
docking able
landers and with roller reefing
making it possible to leave the atmospheric drag zone
near a space
station and getting back again delivering asteroidal
ore to that
Near Earth space station
take a look at:
www.solar-thruster-sailor.info/figs/fig13.html
http://www.solar-thruster-sailor.info/figs/fig14-15.html
http://www.solar-thruster-sailor.info/figs/fig17.html
Greetings:
I would like to mention the obvious, even though it seems nobody
has said it lately. Solar sailing to advance our reach past earth.
Our ancestors reached out beyond the seemingly endless oceans.
They used sails for power. They didn't wait for steam, solid, liquid,
ion or nuclear fuel. They used what was at hand.
The first were explorers. Explorers with courage and faith
backed by governments willing to take risks for the long term good.
It would be ironic if the first for profit missions were done by
solar sails. Simple and dependent again on courage and faith.
I wonder what country will be the one to take risks for the long
term good.
Steve
On Sat, 09 Jul 2005 08:00:04 +0200 Frank nd@...
writes:
There is an element in this line of discussion which posits that solar
sails can provide free transportation within the solar system which
confuses me. It seems to me that solar sails would work only when
moving in the same vector as the solar radiation, i.e. away from the
sun. Have I missed something here?
> There is an element in this line of discussion which posits that solar
> sails can provide free transportation within the solar system which
> confuses me. It seems to me that solar sails would work only when
> moving in the same vector as the solar radiation, i.e. away from the
> sun. Have I missed something here?
Imagine you're in a spacecraft in a roughly circular orbit around the
sun. You open up your solar sails, and you angle them so that the
light reflects off them at an angle, rather than full on and that that
angle is designed to impart a vector exactly opposite to your
direction of motion. What happens? Your orbital velocity goes down.
This won't cause you to stay in the same orbit, though... your kinetic
energy decreases, so your new orbit must, by definition, have the same
orbital energy state. The orbit becomes more elliptical, and you
start dropping towards the Sun.
Soon, you are approaching the orbit you want to be in. In order to
stop your infalling orbit, you change the 'tack' of your solar sails,
and use them to increase your orbital speed rather than decrease it.
As you gradually increase your speed, your orbit circularizes again,
until you are in a smaller, faster orbit at a closer distance from the
Sun.
Thank you for your explanation. It seems like a wonderfully elegant
scheme, although I imagine the forces involved are miniscule and thus it
would work over long periods of time. This would not make it a good
candidate for transporting people, who would require additional life
support (not to mention patience, lol), etc. I would be interested in
hearing your comments in this regard.
> solar
> > sails can provide free transportation within the solar system which
> > confuses me. It seems to me that solar sails would work only when
> > moving in the same vector as the solar radiation, i.e. away from the
>
> > sun. Have I missed something here?
>
> Yes, you have.
>
> Imagine you're in a spacecraft in a roughly circular orbit around the
> sun. You open up your solar sails, and you angle them so that the
> light reflects off them at an angle, rather than full on and that that
>
> angle is designed to impart a vector exactly opposite to your
> direction of motion. What happens? Your orbital velocity goes down.
>
> This won't cause you to stay in the same orbit, though... your kinetic
>
> energy decreases, so your new orbit must, by definition, have the same
>
> orbital energy state. The orbit becomes more elliptical, and you
> start dropping towards the Sun.
>
> Soon, you are approaching the orbit you want to be in. In order to
> stop your infalling orbit, you change the 'tack' of your solar sails,
> and use them to increase your orbital speed rather than decrease it.
> As you gradually increase your speed, your orbit circularizes again,
> until you are in a smaller, faster orbit at a closer distance from the
>
> Sun.
>
Space exploration Computer science Science education
Princeton university
> Thank you for your explanation. It seems like a wonderfully elegant
> scheme, although I imagine the forces involved are miniscule and thus it
> would work over long periods of time. This would not make it a good
> candidate for transporting people, who would require additional life
> support (not to mention patience, lol), etc. I would be interested in
> hearing your comments in this regard.
probes and the like.
>Thank you for your explanation. It seems like a wonderfully elegant
>scheme, although I imagine the forces involved are miniscule and thus it
>would work over long periods of time.
can get the sail the more thrust is available.
The finer the sail foil gets the more mass can made available for
payload.
For instance a 4 square kilometre sail would develop 36 N of thrust
every second on Earth level independent of the sails mass.
Compare this with the 75 mN of Smart 1, the European space probe which
reached the moon with its single ion thruster.
I would say those 36 N are already quite a lot when the mass of those
two different crafts would be compared.
The thrust of the sail would be 480 fold the thrust of the ion
thruster spacecraft at Earth level. The mass, say 15 tons of my solar
sail design would only be 43 fold of the ion thruster spacecraft.
So with growing sail size the thrust/mass relation will become better
and better because most of that sail is very lightweight sail panel.
If we could manage to build a 20 square km sail for instance you could
call the thrust of 180 N this craft would develop every second at
Earth level no longer "minuscule".
Especially when you compare this after a week of acceleration with a
chemical rocket which has depleted its fuel already after a short
period of thrusting time.
>This would not make it a good
>candidate for transporting people, who would require additional life
>support (not to mention patience, lol), etc. I would be interested in
>hearing your comments in this regard.
If you can manage to build a large enough solar sail of the next
generation it would not be out of sight that such a sail could carry
astronauts and their life support.
Next generation solar sail would mean space built and huge size.
But I do think, going after asteroids with remote controlled solar
sail carrier space crafts (skipping the astronauts and their life
support) would bring the fastest results with the highest yields
developing a financially self supporting space transportation infra
structure.
If we have this, we eventually could finance getting astronauts to
Mars.
Frank
www.solar-thruster-sailor.info
For the first solar sail design of a carrier ship with
docking able
landers and with roller reefing
making it possible to leave the atmospheric drag zone
near a space
station and getting back again delivering asteroidal
ore to that
Near Earth space station
take a look at:
www.solar-thruster-sailor.info/figs/fig13.html
http://www.solar-thruster-sailor.info/figs/fig14-15.html
http://www.solar-thruster-sailor.info/figs/fig17.html