Alternative to Rockets

"George Kinley" wrote in message ...
Are there any way for rockets to fly in space , other then throwing mass
out in one direction and moving in other

Perhaps. But rockets work fine for a lot of purposes.
All that is necessary is sensible system design based
upon technology we already know how to handle.

Unfortunately, organizations and people with the
necessary financial resources seem to eschew this route.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

George Kinley wrote:

Are there any**way**for*rockets*to*fly*in*space*,*other*then *throwing*mass
out in one direction and movi

I'm tempted to answer with an electromagnetic tether in a gravity field, but
you'd still throw mass away (even if it is a planet). You can't beat the
conservation of momentum, sorry.

Sincerely
Bjørn Ove

In article ,
George Kinley wrote:
Are there any way for rockets to fly in space , other then throwing mass
out in one direction and moving in other



Solar sails, plasma sails.


--
"For every problem there is a solution which is simple, clean and wrong."
-- Henry Louis Mencken

"George Kinley" wrote in message
...
Are there any way for rockets to fly in space , other then throwing mass
out in one direction and moving in other

Well, that's what "rockets" do. So, no.

But spacecraft in general might take advantage of
light pressure (solar wind), or magnetic fields in
the environment.

George Kinley wrote:

Are there any way for rockets to fly in space , other then throwing mass
out in one direction and moving in other


If they don't work that way, then we don't call them rockets.

One other possibility is a solar sail that uses the pressure of
sunlight, but such a sail would have very low thrust.

In sci.space.tech Mark Foskey wrote:
George Kinley wrote:

Are there any way for rockets to fly in space , other then throwing mass
out in one direction and moving in other


If they don't work that way, then we don't call them rockets.

One other possibility is a solar sail that uses the pressure of
sunlight, but such a sail would have very low thrust.


Strictly speaking, the solar sail too throws mass (photons) out in one
direction and moves in the other direction. Where the mass being thrown
out comes from is not too important.

--
Sander

+++ Out of cheese error +++

Sander Vesik wrote:
Strictly speaking, the solar sail too throws mass (photons) out in one
direction and moves in the other direction. Where the mass being
thrown out comes from is not too important.

I'm sure someone else will also point this out but photons are massless. A
solar sail basically redirects the momentum vector of some of the incident
photons. In order for momentum to be conserved the solar sail must acquire
the vector difference.

Jim Logajan wrote:

Sander Vesik wrote:
Strictly speaking, the solar sail too throws mass (photons) out in one
direction and moves in the other direction. Where the mass being
thrown out comes from is not too important.

I'm sure someone else will also point this out but photons are massless. A
solar sail basically redirects the momentum vector of some of the incident
photons. In order for momentum to be conserved the solar sail must acquire
the vector difference.

On another point, the sail itself may have low mass, but something is
going to have to hold it open and taught.


Richard

In article ,
Richard Lamb wrote:
Jim Logajan wrote:

Sander Vesik wrote:
Strictly speaking, the solar sail too throws mass (photons) out in one
direction and moves in the other direction. Where the mass being
thrown out comes from is not too important.

I'm sure someone else will also point this out but photons are massless. A
solar sail basically redirects the momentum vector of some of the incident
photons. In order for momentum to be conserved the solar sail must acquire
the vector difference.

On another point, the sail itself may have low mass, but something is
going to have to hold it open and taught.


Richard


Possibly centrifugal forces. My favorite design involves unrolling sails
like windowshades from a rotating craft.

--
"The average person, during a single day, deposits in his or her underwear
an amount of fecal bacteria equal to the weight of a quarter of a peanut."
-- Dr. Robert Buckman, Human Wildlife, p119.

Richard Lamb wrote:

Jim Logajan wrote:

Sander Vesik wrote:
Strictly speaking, the solar sail too throws mass (photons) out in one
direction and moves in the other direction. Where the mass being
thrown out comes from is not too important.

I'm sure someone else will also point this out but photons are massless. A
solar sail basically redirects the momentum vector of some of the incident
photons. In order for momentum to be conserved the solar sail must acquire
the vector difference.

On another point, the sail itself may have low mass, but something is
going to have to hold it open and taught.

Radiation pressure plus the solar wind will balloon it out no
problem. Two immediate problems come to mind,

1) Steering in general. How do you tack? If you water sail, what
will pulling on the sheets (lines, for the rest of you) mean in the
context of a solar sail? Where do you set your feet to do the pullng?

2) The curved solar sail - huge area - will have a focus or
caustics. Where do you put the ship? If it crosses the sweet spot
(or the sweet spot crosses it - billowing in solar storms) the ship is
literal toast.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!