Short Mars travel times at high speed.

"Spaceman" wrote in message

Greg Neill wrote:
It is what it is. The acceleration due to the Sun's
gravity depends on position (distance from the Sun),
not velocity.

I never said its pull depends on the objects velocity,
I said the velocity if high enough negates that pull.

Velocity cannot negate force. They are different
things. The force remains. What can happen is
that the relative amount of deflection for a given
length of path can be made smaller.



Horizontal takeoff would be ideal if it weren't
for the atmosphere. The atmophere causes drag,
so you want to get through it as quickly as
possible. If you look at the actual paths of
rockets taking off, you'll see that they start
off going straight up, then bank over as they
get higher, eventually travelling parallel to
the Earth's surface directly below them as they
reach orbital height.

If you want to get there as quickly as possible,
You travel a straight line.

Getting there is not the same thing as staying there.
If you went straight up and turned off your engine,
you'd fall straight back down. You need a velocity
parallel to the surface if you want to remain in
orbit.

wind or not,
To get to a higher altitude, a straight line is the shorter
path always.
Ans a shorter path will burn less fuel in the end.
again.
Traveling to a mountain top proves it.
Why don't you think about such?

Been there, done that.


Enough speed will allow the straight path with an
unpowered flight that will be just enough to negate
the Sun's pull.

No. You can approach stright line, but never achieve
it. The fastest thing around is light, and even it's
path is made curved by the Sun's gravity.

Because light doesn ot have built in rockets.
So..it can't fight gravity,
Spaceships can.
Again you seem to like to ignore that the shortest
distance is a striaght line and the least fuel burned
comes from a straight line also.

Fighting gravity takes fuel. Coasting takes none.



The devil is in the details. Running a non 100%
efficient engine for longer time against the vagaries of
friction on the path will ultimately use more energy
for a longer path.

Correct, longer path = more fuel use.
always.

Not in space.

Now think about that for once.

Been there, done that, got the T-shirt.


The ideal, least energy path to the top of the mountain
would be to be fired from a cannon. Expend the requisite
energy in one efficient burst to impart the kinetic energy
corresponding to the potential energy difference between
the bottom and top of the mountain.

The ideal path would be a straight line.
Again, you seem to ignore the fact that a straight line
uses the least fuel.

It would take an infinite amount of energy to traverse
a straight line free-fall path through a gravitational
field. The minimum possible energy expenditure is
dictated by the potental energy difference in the
starting and ending locations. That can only be achieved
in a frictionless environment with a perfect engine.
The next best thing is a ballistic trajectory.

In space there is (essentially) no friction. So unpowered
motion is free.

And if enough fuel that brings you to that curve
is used in a straight path instead, you will be getting there
faster for the same amount of fuel.

No, you must burn *more* fuel to follow a straight line
path if you're countering acceleration rather than just
letting the acceleration take you along.

The fuel is the savings. Intertia is, well, inertia.

Fuel is always saved by traveling a straight line.
Do you actually think taking a longer path
uses less fuel?

Absolutely, in orbital manouvering. It is mathematically
proven as well as empirically observed. Remember,
with a ballistic trajectory you run the engine for only
a very brief time, whereas to constantly "drive" a
non inertial path you need to run the engine constantly.

Again, I invite you to prove such to a trip the the
mountain top.

Suppose you need to get to the other side of a mountain.
You can either coast around it on a perfectly flat
road, or drive straight up and straight down again.
What do you think will take more fuel?

Burning no fuel is always cheapest. Burning just the
needed fuel as efficiently as possible is the next
cheapest.

Again, shorter paths will burn less fuel.
You seem to want to ignore that fact.

Not if the path length is irrelevant to the fuel
consumption. Remember, for 99% of the trip you
need burn *no* fuel for a ballistic orbital path.


Staight up, of course, if highest altitude was your goal.
Air friction determines the ideal initial angle. If there
were no air friction, and the bullet could pass freely
through the Earth (obviously a hypothetical situation) any
angle would do as the bullet would go into an orbit with a
major axis fixed by the initial position and velocity. It
would reach the same height above the "surface" eventually
(apogee).


Our notions of efficient paths on Earth are misleading
when it comes to space travel, since down here we tend
to take into account the "difficulty" of terrain and
air friction and other losses. In space the cheapest
way to travel is to just coast after making the most
efficient expenditure of fuel that we can (usually
meaning a short efficient rocket firing).

In space you don't have to worry about air friction.

In reality the shortest path is the least fuel burned.

Not if you don't have to burn fuel over the whole path.
Then the path length is irrelevant.

and not once is there 0 gravity towards Mars.
so the straight path will still win for least fuel burned
once speed is achieved.

No. You'll be contantly fighting gravity to maintain
a straight line, which is a waste of fuel for the sake
of geoemtry, whereas letting the ship coast along
without burning fuel costs nothing but time.

Again,
If you don't want to think about taking the trip to
the top of the mountain and the trip back will
be "basically free" then you don't get the fact about
shortest distance will use least fuel all the time.

James, I've done the math and solved for the most
efficient, least fuel path. It goes by the name
of the Hohmann Transfer (there are special cases
where another trajectory consisting of a pair of
elliptical transfers can be slightly more efficient)
Look it up.

"Spaceman" wrote in message

spudnik wrote:
the quickest path between two places is a slalom
(brachistochrone or tautachrone per Liebniz' calculus.

The why do downhill skiers make it past the finish line first
and faster.

The quickest path at a set speed is a straight line.
The least fuel burned at the same set speed is also a straight path.
Why are such simple facts ignored so well to come
up with this curved path crap?
Such ignorance of reality is amazing.

You're ignoring the effect of gravity and asssuming
that the ship has a road to run on. Skiiers must
follow the mountain terrain and are not free to
choose their own 3D trajectory. If they were, and
could ignore the ski gates, they would follow a
curved path sa "spudnik" wrote. It's a classic
2nd year calculus problem.

Greg Neill wrote:
"Spaceman" wrote in message

Greg Neill wrote:
It is what it is. The acceleration due to the Sun's
gravity depends on position (distance from the Sun),
not velocity.

I never said its pull depends on the objects velocity,
I said the velocity if high enough negates that pull.

Velocity cannot negate force.

So wrong, it is not even funny that you stated that.

Please prove a longer path will take less energy to travel than a
shorter path Greg,
When you do, tell the car companies that so they can laugh
also.


snipped rest of ignorance of a known fact about paths vs energy
use.

--
James M Driscoll Jr
Spaceman

Greg Neill wrote:
"Spaceman" wrote in message

spudnik wrote:
the quickest path between two places is a slalom
(brachistochrone or tautachrone per Liebniz' calculus.

The why do downhill skiers make it past the finish line first
and faster.

The quickest path at a set speed is a straight line.
The least fuel burned at the same set speed is also a straight path.
Why are such simple facts ignored so well to come
up with this curved path crap?
Such ignorance of reality is amazing.

You're ignoring the effect of gravity and asssuming
that the ship has a road to run on.

No I am not.
I am ignoring your ignorance of a longer path needed more
fuel than a shorter path would.
And sadly, you are ignoring that fact completely to come
up with your "curved path nonsense".

Hint Greg:
There is no spot between here and Mars where there is no
gravity.
so even when you are "freefalling" you are taking a longer
path and will need to make it up with fuel again to
once again fight the gravity taking the longer trip.

Skiiers must
follow the mountain terrain and are not free to
choose their own 3D trajectory. If they were, and
could ignore the ski gates, they would follow a
curved path sa "spudnik" wrote. It's a classic
2nd year calculus problem.

It's a joke and you don't seem to know how stupid it really
is in reality.
The shortest distance is the straight line, and the straght
line (even when fighting gravity) will burn less fuel.

--
James M Driscoll Jr
Spaceman

"Spaceman" wrote in message

Greg Neill wrote:
"Spaceman" wrote in message

Greg Neill wrote:
It is what it is. The acceleration due to the Sun's
gravity depends on position (distance from the Sun),
not velocity.

I never said its pull depends on the objects velocity,
I said the velocity if high enough negates that pull.

Velocity cannot negate force.

So wrong, it is not even funny that you stated that.

Please prove a longer path will take less energy to travel than a
shorter path Greg,

Get yourself almost any text on orbital mechanics.

When you do, tell the car companies that so they can laugh
also.

Cars are not spaceships. Cars are constrained to run on
the roads provided.

If roads were carved as curved tunnels from point to
point on the earth, with the right curve a car could
get from any point to any other point on the surface
using practically no fuel! Of course, every trip
would take a fixed time of 42 minutes, which might
prove inconvenient if you just wanted to go down
the block.

Greg Neill wrote:
"Spaceman" wrote in message

Greg Neill wrote:
"Spaceman" wrote in message

Greg Neill wrote:
It is what it is. The acceleration due to the Sun's
gravity depends on position (distance from the Sun),
not velocity.

I never said its pull depends on the objects velocity,
I said the velocity if high enough negates that pull.

Velocity cannot negate force.

So wrong, it is not even funny that you stated that.

Please prove a longer path will take less energy to travel than a
shorter path Greg,

Get yourself almost any text on orbital mechanics.

Why?
so I can read crap that is proven wrong about straight
paths vs curved paths and become brainwashed like
you to think a longer path could take less energy?
No thanks.

LOL


Cars are not spaceships. Cars are constrained to run on
the roads provided.

Energy is energy and shorter paths are shorter paths.
Car or spaceship makes no difference in the end.
The shortest path will always use the least fuel.


If roads were carved as curved tunnels from point to
point on the earth, with the right curve a car could
get from any point to any other point on the surface
using practically no fuel! Of course, every trip
would take a fixed time of 42 minutes, which might
prove inconvenient if you just wanted to go down
the block.

Wow,
you sure are lost with your curvature stuff.
A straight tunnel would be the least fuel needed
from point A to point B.
a curved tunnel up or down from such would burn more fuel
in the end no matter what you may think.
You simply can not grasp that simple fact huh?

--
James M Driscoll Jr
Spaceman

"Spaceman" wrote in message

Greg Neill wrote:
"Spaceman" wrote in message

spudnik wrote:
the quickest path between two places is a slalom
(brachistochrone or tautachrone per Liebniz' calculus.

The why do downhill skiers make it past the finish line first
and faster.

The quickest path at a set speed is a straight line.
The least fuel burned at the same set speed is also a straight path.
Why are such simple facts ignored so well to come
up with this curved path crap?
Such ignorance of reality is amazing.

You're ignoring the effect of gravity and asssuming
that the ship has a road to run on.

No I am not.
I am ignoring your ignorance of a longer path needed more
fuel than a shorter path would.
And sadly, you are ignoring that fact completely to come
up with your "curved path nonsense".

Hint Greg:
There is no spot between here and Mars where there is no
gravity.
so even when you are "freefalling" you are taking a longer
path and will need to make it up with fuel again to
once again fight the gravity taking the longer trip.

No. You give the ship the necessary impulse at the
beginning of the trip and allow it to coast all the
way to the vicinity of Mars' orbit. Then apply another
short burst to circularize the orbit to coincide with
that of Mars.


Skiiers must
follow the mountain terrain and are not free to
choose their own 3D trajectory. If they were, and
could ignore the ski gates, they would follow a
curved path sa "spudnik" wrote. It's a classic
2nd year calculus problem.

It's a joke and you don't seem to know how stupid it really
is in reality.

Reality is not stupid. Ignoring it by trying to apply
your backyard experience is.

The shortest distance is the straight line, and the straght
line (even when fighting gravity) will burn less fuel.

No. The shortest distance may be a straight line, but
it's not always the most energy efficient. Remember,
you don't need to keep your engine running the whole
way.

"Spaceman" wrote in message

Greg Neill wrote:
"Spaceman" wrote in message

Greg Neill wrote:
"Spaceman" wrote in message

Greg Neill wrote:
It is what it is. The acceleration due to the Sun's
gravity depends on position (distance from the Sun),
not velocity.

I never said its pull depends on the objects velocity,
I said the velocity if high enough negates that pull.

Velocity cannot negate force.

So wrong, it is not even funny that you stated that.

Please prove a longer path will take less energy to travel than a
shorter path Greg,

Get yourself almost any text on orbital mechanics.

Why?
so I can read crap that is proven wrong about straight
paths vs curved paths and become brainwashed like
you to think a longer path could take less energy?
No thanks.

Ignorance is not a way of knowing things, as you
are very plainly demonstrating.

Cars are not spaceships. Cars are constrained to run on
the roads provided.

Energy is energy and shorter paths are shorter paths.
Car or spaceship makes no difference in the end.
The shortest path will always use the least fuel.


If roads were carved as curved tunnels from point to
point on the earth, with the right curve a car could
get from any point to any other point on the surface
using practically no fuel! Of course, every trip
would take a fixed time of 42 minutes, which might
prove inconvenient if you just wanted to go down
the block.

Wow,
you sure are lost with your curvature stuff.
A straight tunnel would be the least fuel needed
from point A to point B.

No. With a tunnel that descends from the starting
point and ascends to the termination, the car could
coast the whole way with no fuel at all if there
were no friction. Like dropping a marble down the
side of a curved bowl, it would roll down one side
and back up the other.

a curved tunnel up or down from such would burn more fuel
in the end no matter what you may think.
You simply can not grasp that simple fact huh?

You obviously know nothing about conservation of energy.

Greg Neill wrote:
No. The shortest distance may be a straight line, but
it's not always the most energy efficient. Remember,
you don't need to keep your engine running the whole
way.

Let me correct a goof up I have said,
I used the "fuel" word where I should have used
the energy word.

The shortest distance being a straight line will
always take the least amount of energy,
and the longer the distance will take more energy
always.
and
A slingshot effect is simply grabbing that extra energy needed
for the longer trip.
Once you have used up the slingshot,
you are back to square one.
The shortest distance is best again, unless you
can get another slingshot.
but sadly curving slowly outward away from the sun,
by taking the "curved path to Mars" is not "gathering energy"
and hence the longer path doing such is stupid and will
not use less energy and in fact would need more energy
coming from the spaceship to do such.
So,
I admit my use of the word fuel was wrong,
but the energy will always be more used for the longer
path.


Now show me a circular path away from gravity that
will use less energy than the straight path would Greg.

Greg Neill wrote:
No. With a tunnel that descends from the starting
point and ascends to the termination, the car could
coast the whole way with no fuel at all if there
were no friction. Like dropping a marble down the
side of a curved bowl, it would roll down one side
and back up the other.

I admit, I should not have used the word "fuel"
I should have only used the word energy.
so.
Please show me a longer path from A to B that does
not require more energy to travel than a shorter path
from A to B would.


--
James M Driscoll Jr
Spaceman