Is the “Well, you could just ask it’s captain for permission to come aboard…
” spoken by the other visible character, or by someone aboard The Catia’s
Pride via external speaker?
Also, “it’s” is the abbreviated version of “it is”.
The possessive should be “its”.
(Sorry, too much time spent as a part-time professional proofreader.)
I hope he is what she thinks he is and this
isn’t going to bite her in the ass.
Ah yes, jumping to conclusions… not a good
idea when you’re in the dark, you can’t see the
traps… like the entire crew being on board…
Fully armed and has a nice cell for you to lay
your misshapen head in…
I can see why the name hammerhead, their
eyes are set wide apart like a hammerhead
shark’s.
Glad you shared that. After that phone call in the previous installment I was beginning to
wonder if Larissa might not be a double agent. I didn’t think Matt Costman could screw
up that bad but I would never put throwing in a plot twist (or red herring) past you.
Unless she’s into that, of course. Funniest reply I could think of was
“That sounds delightful, but my wife and I have an understanding.
I have to call her and see if she’s available to join us first.”
President Elect Toxic Deplorable Racist SAH Neanderthal B Woodman Domestic Violent Extremist SuperStraight
“Slithering Hellbird”.
I don’t know whether to snicker & LOL, or be afraid.
Does it have a reputation based on victory against an honorable foe?
Or is its rep based on bullying, bluff and bravado?
I seriously doubt there is any honor behind that name,
more like terror, intimidation, and straight up cruelty.
Hellbirds have been depicted in paintings and in books
of anything from undead rotted vultures to bat wings
with only fanged mouths. Slithering makes me think
of leaches or snakes with wings to harass you
between times of torture in hell.
They are no doubt under cover near by fully manned
ready to scare off or kill anyone trying to force their
way in. Catia’s Pride was the first of many armed ships
built to trade first, and defend when needed. Top of
the line flagship. Not the best thing to be examined in
detail by the core.
After it’s last refit on Catia, it is no longer a trade ship. Most of the
old cargo space was converted to things necessary, such as more
life support, for the increased manpower. Such as four fighter crew,
etc. While it can still carry a lesser amount of cargo, the Pride is
now mostly an armed diplomatic courier. Perfect for carrying the
Empress Teresa’s envoy around, for example.
I have some bad news, My wife took a bad fall yesterday. She refused
to let me call 911 so I used my father’s rlling walker to move her to our
bed. She can’t move anymore so I’m calling 911 now, I may not be on
much for a while. Wish us luck, she has that osteoporosis pretty bad
and has broken bones from a simple fall before.
Damn hospital wouldn’t let me stay with her,
she broke her hip right at the ball…
so she’s getting a new hip tomorrow-ish.
Seems she has early pneumonia too, I’m a mess
guys but I’ll let all know.
I just got back from the hospital, they are waiting until tomorrow
to do the hip replacement. I had to take care of things at home
or I would of stayed until visiting hours were over. She broke off
the hip ball clean off so they are going to do a partial replacement.
All she did was trip over a chair leg.
OK, surgery went well, she’s lucid and complaining about
the numbness in her legs heh. They did a spinal since her
COPD and a general would of been bad, very bad.
We should find out tomorrow when she’s coming home,
I’ve hardly slept the last 3 days….
I have a feeling that Larissa will kidnap
Mr. Jeffery and get him out of the CSA when the “fun” starts.
Against his will? I doubt it.
I have a feeling Larissa can be VERY persuasive.
She doesn’t want to tip him off, but she doesn’t want him hurt,
or “interrogated” by CSA Stazi afterwards.
Maybe totally “turn” him, then REturn him to the CSA to take up.
….other……. duties.
Starting from a Earth-like planet takes insane amounts of energy.
(And fuel, especially if your using classical fuel-burning, gas ejecting
engines)
How’s that done in your universe for anybody outside the Empire?
That red hellbird thingy doesn’t really look like it’s got huge fuel tanks,
but they still land on a planet like it’s nothing.
Most (all) non-Terran ground-orbit spacecraft we have seen looked more or less
aerodynamic. As we haven’t seen much in part of fuel tanks I’d go with some
kind of very highly advanced and miniaturized fusion reactor if we stay within
known science.
Going into the more Science Fiction part of fictional science, the old
matter/anti-matter reactor is a classic. Followed by many other fictional methods
of power generation which includes fictional materials to do so.
Sad thing, the Space 1999 Eagles ALMOST work, from a purely technical aspect,
EXCEPT, they don’t have nearly enough reaction mass, nor are they aerodynamic
enough for atmospheric flight, without a whole LOT of handwavium…
sci-fi.. no really there are other engines out there..
BUT because of the “Space Race”.! the PTB used the
known , faster , quick to build ,. and stuck with it
because you know,, tradition.
so now we are ‘starting’ to use the lesser known engines.
such as the ION engine (which came out in 1911.).
Ion engines (as we know them) only work in deep vacuum and
are very low on thrust.
The reason we’re stuck with chemical rockets for now is simply
that they’re still better suited for launching off the planet than any
other known propellant.
With any kind of “non-SiFi” propulsion it always comes down to
an equation like this: Δ v = ve * ln(m0/mf).
Read: to change the speed of the craft of mass mf by Δ v you have
to bring along additional mass and kick that in the opposite direction
at velocity ve. (m0 is the “starting mass”, including the fuel or whatever
you throw off your ship).
The logarithm means that you have to bring exponentially more mass
for higher and higher Δ v , because you have to accelerate that mass
too, until you need it.
(Details see: https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation)
Other means of changing speed like solar sails or sling shot maneuvers
won’t work for taking off from a planet.
Ejecting photons might also work, but not without severe damage to the
planet you’re trying to start off of.
What MIGHT work inside an atmosphere would be some kind of what-ever-
powered jet engine, using the planetary air as mass-to-eject – you would
have to reach something like Mach 10, which should be possible using jet
engines).
This type of engine wouldn’t work in deep space, obviously.
From what I’ve read, the least amount of speed to reach escape
velocity is mach 7, but that is strictly if you were shooting it out
of a gun. Like in SG-1 they had developed the X301, a multi-engine
plane that could launch with jets, switch to ram-jets in the mid to
upper atmosphere, then switch to a rocket to reach orbit. Not very
practical, but effective. In vacuum they would need maneuvering
jets to correctly aim and maneuver, while in atmosphere they would
use the control surfaces. Heavy on maintenance however and would
take time for the prep for orbital maneuvers. A coronal mass ejection
could disable the plane’s electronics while in orbit as well.
If you want to escape Earth’s gravity you have to be at least 11km/s fast.
You can shave off a few hundred m/s if you start on the equator and start
in the direction of Earth’s own rotation. https://en.wikipedia.org/wiki/Escape_velocity
If you just want to reach a low Earth orbit (and stay in orbit) you’d only need
around 7 km/s. (But you’d need to accelerate again to then escape).
A short trip to “space” in the ways of flying 62 miles straight up are much easier.
But you’d immediately begin to fall again – unless your speed is high enough
to at least stay in ordbit.
i meant,, as an example that we had “Other” choices at that time.
but they went with FAST,. cheap an already on hand..
oh and some of those “choices” were classified..
ION engines are still in their infancy, between the power requirements
and the risk of radiation, there is still much to hammer out. PC had
remarked on a strip about hydrogen/fusion engines leaving a vapor
trail (like oxy/hydrogen engines on the shuttle/spacex engines do)
but ION engines thrust isn’t as yet strong enough to lift anything
heavier than a model airplane. Strictly a space engine so far.
infancy? they have been around since 1911..
they are used on quite a few, out of earth orbit
missions…
radiation.?? they are electric.. only concern is
the thermal, from the ionized Xenon into
Plasma..
again,, this (ion) was just an example of the
other choices we had,, but they went with the
fastest..
Ion engines are rockets in the sense that they accelerate the
craft by “throwing stuff” in the opposite direction.
(Think of the recoil of a gun. Only that the recoil is what you want).
In other words you need to carry the mass you want to eject with
you until you need it to provide you with trust.
Assume you have some “magic” energy source like antimatter or
ram scoops – so you don’t have to worry about fuel weight.
Imagine that your ion drive ejects particles at 110 km/s, which is
pretty fast but not unrealistic.
By solving the rocket formula I provided in a previous post for starting
mass, you find that you’d have to bring along 10% “extra stuff to throw
away” for a single take-off from Earth’s surface. If you want to keep
changing your speed and direction of travel without having to refuel once
you cleared the planet, you’ll have to take the extra material to eject with
you. Which means you’d have to accelerate THAT mass too.
I’m not sure how a fighter-like space craft using non-“grav-magic”
engines should be able to maneuver in battle. You’d have to calculate the
“maximum delta v without refuel” and take that much dead weight with
you. And if you run out of stuff to eject you’re a sitting duck. (It’s not
fuel in a conventional sense, more like ballast to leave behind)
As for radiation: it’s called “ion drive” for a reason. You *are* in fact
using ionized particles for propulsion. Alpha radiation is nothing other
than high speed ionized Helium particles. Not so different from using
Xenon or whatever.
About “around since forever”: The ancient Greeks knew the concept
of steam engines. And we know that antimatter would be a very
efficient fuel since at least Einstein. And fusion energy has been “just
around the corner” for at least 4 or 5 decades now.
Just because you can formulate a concept that should work, doesn’t
mean you know how to actually build something usable based on
said concept, current ion engines still have very limited use, because
they produce very little thrust and seemed to be working only in the
vacuum of deep space.
I say that because they’ve been around over 100 years but were largely
ignored in that time. Like the areospike engine, they were mostly treated
as an oddity and stuck with the “bell-n-boom” Plus the tech is barely able
get any real performance as yet.
Correct me if I’m wrong, but isn’t “Escape Velocity” the speed you
need to be at when you leave the Earth’s surface in order to coast
the rest of the way out of the Earth’s gravity well?
Like a cannon shell fired straight up from the surface.
The higher a rocket can reach under power, the slower it can be
moving when it runs out of fuel in order to coast the rest of the way.
Technically, you could power your way out of Earth’s gravity well at
a walking pace if you could carry enough fuel.
Maybe it’s easier to explain if we’re doing it the other way around.
Consider releasing a pebble right “at the edge” of Earth’s gravity well at a
perfect 0 mph relative to Earth.
It would start falling. And falling faster …
By the time it hit Earth it would be doing 11km/s.
So to climb out of the well you’d need to get at least that
much total kinetic energy.
And you can’t allow your vessel to run out of fuel by the way.
At least not if you’re planing on coming back in a controlled way.
Or landing somewhere else.
(Damn am I bad at explaining stuff in a foreign language)
Another way to look at things: hovering just a few meters above ground
(i.e.: your “walking speed” example taken to the extreme) would achieve
nothing but waste massive amounts of fuel because you’d have to accelerate
at one gee, just to hold your position.
In a way the most efficient way to “leave the well” would be the canon shell fired
at 11 km/s because you’d use an EXTERNAL means of propulsion – i.e. one you
don’t have to take with you, one that doesn’t add to the total mass of your craft.
Of course the acceleration needed for that is certifiably un-survivable.
The notion of a “gravity well” is a bit misleading: you’re never quite out of
reach of Earth’s gravity. It’s just that if you get away far enough, the gravity
of other bodies (the Sun usually) becomes dominant.
Since there’s no friction in space you never can stand perfectly still anywhere.
The moment you stop, you start falling towards something. The equivalent to a stand
still is to orbit around something. Earth, the Moon, Sun … whatever.
Using your pebble example, once we had it stationary at the edge of
the Earth’s gravity well, we would only have to move it outward at
walking speed for it to escape.
I fail to see where my example is wrong, you could power your way from
the Earth’s surface to outside of the gravity well at a walking pace,
if you had enough fuel. As I said, “escape velocity” is merely the
velocity which must be imparted near-instantaneously to an object to
let it leave the surface and coast outside of the Earth’s well. It
does not apply to objects moving at a constant pace. They can escape
at any speed, if they have the fuel to move far enough.
In other words, if a space ship leaves the Earth at 100KPH and carries
sufficient fuel to move 1 million K, what’s going to stop it and make
it return to Earth?
Two cases: assuming there’s only the Earth and your craft in the whole wide universe.
In this case you can’t actually leave Earth’s influence, it might be infinitesimal small, but
the pull would still be there. But yes, if you’re far enough out, you might be orbiting at walking
speed. If you slow down to an absolutely perfect stand-still (relative to Earth) you’d drop
straight down, hitting the atmosphere at 11km/s.
As for doesn’t apply for objects moving at a constant pace: to be doing that you’d need to
provide exactly as much thrust as the pull from the planet you’re trying to escape.
If you integrate that (= sum it up) over the course of your flight you’d be at least at the same
amount as if you left in one big blast. There’s no free lunch.
In the real solar system, it is possible to leave Earth’s influence in the sense that the pull from
the Sun becomes dominant by several orders of magnitude. You will then have to be fast enough
to orbit HER – in other words, you’d have to be as fast as a planet as far away from Sun as you.
For example: Saturn is circling at 9.7 km/s and even as far out as Neptune (4.5 billion km from Sun!)
you’d still need 5.4 km/s for a stable orbit (what you called stationary).
But it’s not as much about just dropping back to a planet – if you have enough time to use an efficient
trajectory and can avoid other planets that’s normally not a big problem. My concern is more about
maneuverability.
Just think about the delays involved with “back to reality” spaceflight and try to imagine a battle evolving
at that time scale.
“Captain, there’s a hostile 100,000 miles out.”
“Set course to intercept and wake me same time again tomorrow.”
That is, if you’re lucky and heading at least somewhat in the right direction.
If you’d have to turn around – forget it.
Even as far away from Earth as the moon you’d be doing over 2 miles per
second, you can’t just pull the brakes or you’d drop like rock.
And even if you’d try to stop your craft: that’s a delta v of around 3 km/s
which would require a ludicrous amount of propellant (in a sense that you
can maybe pull it off just a few time before needing to restock).
Any at least somewhat efficient trajectory would probably take you around the
planet.
And even if you’re able to intercept them, boarding would require to adjust your
speeds perfectly to match theirs.
(Forget about “She’s coming about for another attack”, Star Trek-like that would
require delta vs of well beyond taking off of a planet)
Compare that to your own gravity drive. Imperial vessels can basically just zoom
about as they like (ok, yeah, they’d have to get rid of a bunch of excess heat and find
some other mass to pull themselves towards to, but that’s almost trivial in
comparison).
Best example of shooting an object into space was done by accident
during a nuclear test. Now it was never found or any proof of it
exists but, when they did the first underground A-bomb test they
lowered it down a very deep shaft and capped it with a heavy steel
“manhole cover” which was shot straight up and never seen again. A
very basic version Of Jules Verne’s “Man on the moon”.
It wasn’t entirely an “accident” tho. They weren’t sure exactly how
the sealing cap would deal with the blast. And there’s no prove it
actually made it into space, let alone out of Earth’s influence.
All they got was a single frame from a high speed camera –
so they do have a lower estimate of the speed, but
not a exact number.
Other articles about that same event speculated that the
thingy might have been disintegrated or slowed down below
escape velocity (and burnt up on re-entry).
But all that is just speculation. They never found any part of it.
Last panel:
Is the “Well, you could just ask it’s captain for permission to come aboard…
” spoken by the other visible character, or by someone aboard The Catia’s
Pride via external speaker?
Also, “it’s” is the abbreviated version of “it is”.
The possessive should be “its”.
(Sorry, too much time spent as a part-time professional proofreader.)
Patience, Sam. Patience.
Not sure who said this one:
“They say patience is a virtue, but it’s not one of mine.”
And, to quote that great Spanish philosopher, Inego Montoya:
“I hate waiting.”
I hope he is what she thinks he is and this
isn’t going to bite her in the ass.
Ah yes, jumping to conclusions… not a good
idea when you’re in the dark, you can’t see the
traps… like the entire crew being on board…
Fully armed and has a nice cell for you to lay
your misshapen head in…
I can see why the name hammerhead, their
eyes are set wide apart like a hammerhead
shark’s.
She’s Imp Intel, been in the CSA for years as a smuggler.
She knows exactly what she’s doing.
I’m sorry, seen too many cop shows and spy
movies to not wonder that heh. I doubt the
CSA is that smart to be honest.
Glad you shared that. After that phone call in the previous installment I was beginning to
wonder if Larissa might not be a double agent. I didn’t think Matt Costman could screw
up that bad but I would never put throwing in a plot twist (or red herring) past you.
Unless she’s into that, of course. Funniest reply I could think of was
“That sounds delightful, but my wife and I have an understanding.
I have to call her and see if she’s available to join us first.”
“Slithering Hellbird”.
I don’t know whether to snicker & LOL, or be afraid.
Does it have a reputation based on victory against an honorable foe?
Or is its rep based on bullying, bluff and bravado?
I seriously doubt there is any honor behind that name,
more like terror, intimidation, and straight up cruelty.
Hellbirds have been depicted in paintings and in books
of anything from undead rotted vultures to bat wings
with only fanged mouths. Slithering makes me think
of leaches or snakes with wings to harass you
between times of torture in hell.
The AI fighters are acting up.
Or maybe just the Catia’s Pride AI?
This doesn’t have those two carry alongs.
They are no doubt under cover near by fully manned
ready to scare off or kill anyone trying to force their
way in. Catia’s Pride was the first of many armed ships
built to trade first, and defend when needed. Top of
the line flagship. Not the best thing to be examined in
detail by the core.
After it’s last refit on Catia, it is no longer a trade ship. Most of the
old cargo space was converted to things necessary, such as more
life support, for the increased manpower. Such as four fighter crew,
etc. While it can still carry a lesser amount of cargo, the Pride is
now mostly an armed diplomatic courier. Perfect for carrying the
Empress Teresa’s envoy around, for example.
Yeah I know it was to mention it was top-of-the-line
more than anything, I figured it’s why you mentioned
that they were going to P’tero in the story.
I have some bad news, My wife took a bad fall yesterday. She refused
to let me call 911 so I used my father’s rlling walker to move her to our
bed. She can’t move anymore so I’m calling 911 now, I may not be on
much for a while. Wish us luck, she has that osteoporosis pretty bad
and has broken bones from a simple fall before.
Damn. All we can do is wish you the best, but that much we’ll do.
Luck , an prayers..
Poor lady! Sorry to hear that. A stranger here wishes her the best, and healing IJN.
Darn, I hope things workout for you both.
Best wishes is all any of us can do.
You have all we can give.
How terrible.
Wish hope, and pray for the best for your wife and you.
My mother and aunts had those problems.
May your wife heal well and quickly.
Damn hospital wouldn’t let me stay with her,
she broke her hip right at the ball…
so she’s getting a new hip tomorrow-ish.
Seems she has early pneumonia too, I’m a mess
guys but I’ll let all know.
My best wishes to the both of you.
Hope she gets well soon.
They are doing the hip replacement in a few hours…
If you don’t hear from me in a few days you’ll know
if it doesn’t go well.
God bless you and yours,
and bless your efforts on behalf
of your beloved wife of your life.
I just got back from the hospital, they are waiting until tomorrow
to do the hip replacement. I had to take care of things at home
or I would of stayed until visiting hours were over. She broke off
the hip ball clean off so they are going to do a partial replacement.
All she did was trip over a chair leg.
OK, surgery went well, she’s lucid and complaining about
the numbness in her legs heh. They did a spinal since her
COPD and a general would of been bad, very bad.
We should find out tomorrow when she’s coming home,
I’ve hardly slept the last 3 days….
The Pride is staring at the wall just like Terran
feline. What eldritch horror are they hunting?
Those hammerheads should be careful, but how
much will it take to knock their pride down a
couple notches before they will pay attention?
Lurklurklurk!
Paint ball!!! Full auto!!!!!
psst!psst!psst!psst!psst!psst!psst!psst!psst!psst!
crappy thing….. and why do I have neon pink shoes
now……
h HA! *serpentine*
She’s a twisty little kitty, all right.
I have a feeling that Larissa will kidnap
Mr. Jeffery and get him out of the CSA when the “fun” starts.
Against his will? I doubt it.
I have a feeling Larissa can be VERY persuasive.
She doesn’t want to tip him off, but she doesn’t want him hurt,
or “interrogated” by CSA Stazi afterwards.
Maybe totally “turn” him, then REturn him to the CSA to take up.
….other……. duties.
Wouldn’t surprise me any, Impsec or not she is a
woman that cares and life in the CSA is about to
get a lot harder… or easier, only PC knows…
A question about non-grav vessels.
Starting from a Earth-like planet takes insane amounts of energy.
(And fuel, especially if your using classical fuel-burning, gas ejecting
engines)
How’s that done in your universe for anybody outside the Empire?
That red hellbird thingy doesn’t really look like it’s got huge fuel tanks,
but they still land on a planet like it’s nothing.
I’ll let my readers speculate on that.
Most (all) non-Terran ground-orbit spacecraft we have seen looked more or less
aerodynamic. As we haven’t seen much in part of fuel tanks I’d go with some
kind of very highly advanced and miniaturized fusion reactor if we stay within
known science.
Going into the more Science Fiction part of fictional science, the old
matter/anti-matter reactor is a classic. Followed by many other fictional methods
of power generation which includes fictional materials to do so.
Sad thing, the Space 1999 Eagles ALMOST work, from a purely technical aspect,
EXCEPT, they don’t have nearly enough reaction mass, nor are they aerodynamic
enough for atmospheric flight, without a whole LOT of handwavium…
sci-fi.. no really there are other engines out there..
BUT because of the “Space Race”.! the PTB used the
known , faster , quick to build ,. and stuck with it
because you know,, tradition.
so now we are ‘starting’ to use the lesser known engines.
such as the ION engine (which came out in 1911.).
Ion engines (as we know them) only work in deep vacuum and
are very low on thrust.
The reason we’re stuck with chemical rockets for now is simply
that they’re still better suited for launching off the planet than any
other known propellant.
With any kind of “non-SiFi” propulsion it always comes down to
an equation like this: Δ v = ve * ln(m0/mf).
Read: to change the speed of the craft of mass mf by Δ v you have
to bring along additional mass and kick that in the opposite direction
at velocity ve. (m0 is the “starting mass”, including the fuel or whatever
you throw off your ship).
The logarithm means that you have to bring exponentially more mass
for higher and higher Δ v , because you have to accelerate that mass
too, until you need it.
(Details see: https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation)
Other means of changing speed like solar sails or sling shot maneuvers
won’t work for taking off from a planet.
Ejecting photons might also work, but not without severe damage to the
planet you’re trying to start off of.
What MIGHT work inside an atmosphere would be some kind of what-ever-
powered jet engine, using the planetary air as mass-to-eject – you would
have to reach something like Mach 10, which should be possible using jet
engines).
This type of engine wouldn’t work in deep space, obviously.
Oops. Math error. It would have to reach like 11 km/s which is
something like Mach 33 rather than Mach 10.
From what I’ve read, the least amount of speed to reach escape
velocity is mach 7, but that is strictly if you were shooting it out
of a gun. Like in SG-1 they had developed the X301, a multi-engine
plane that could launch with jets, switch to ram-jets in the mid to
upper atmosphere, then switch to a rocket to reach orbit. Not very
practical, but effective. In vacuum they would need maneuvering
jets to correctly aim and maneuver, while in atmosphere they would
use the control surfaces. Heavy on maintenance however and would
take time for the prep for orbital maneuvers. A coronal mass ejection
could disable the plane’s electronics while in orbit as well.
If you want to escape Earth’s gravity you have to be at least 11km/s fast.
You can shave off a few hundred m/s if you start on the equator and start
in the direction of Earth’s own rotation.
https://en.wikipedia.org/wiki/Escape_velocity
If you just want to reach a low Earth orbit (and stay in orbit) you’d only need
around 7 km/s. (But you’d need to accelerate again to then escape).
A short trip to “space” in the ways of flying 62 miles straight up are much easier.
But you’d immediately begin to fall again – unless your speed is high enough
to at least stay in ordbit.
i meant,, as an example that we had “Other” choices at that time.
but they went with FAST,. cheap an already on hand..
oh and some of those “choices” were classified..
ION engines are still in their infancy, between the power requirements
and the risk of radiation, there is still much to hammer out. PC had
remarked on a strip about hydrogen/fusion engines leaving a vapor
trail (like oxy/hydrogen engines on the shuttle/spacex engines do)
but ION engines thrust isn’t as yet strong enough to lift anything
heavier than a model airplane. Strictly a space engine so far.
infancy? they have been around since 1911..
they are used on quite a few, out of earth orbit
missions…
radiation.?? they are electric.. only concern is
the thermal, from the ionized Xenon into
Plasma..
again,, this (ion) was just an example of the
other choices we had,, but they went with the
fastest..
Ion engines are rockets in the sense that they accelerate the
craft by “throwing stuff” in the opposite direction.
(Think of the recoil of a gun. Only that the recoil is what you want).
In other words you need to carry the mass you want to eject with
you until you need it to provide you with trust.
Assume you have some “magic” energy source like antimatter or
ram scoops – so you don’t have to worry about fuel weight.
Imagine that your ion drive ejects particles at 110 km/s, which is
pretty fast but not unrealistic.
By solving the rocket formula I provided in a previous post for starting
mass, you find that you’d have to bring along 10% “extra stuff to throw
away” for a single take-off from Earth’s surface. If you want to keep
changing your speed and direction of travel without having to refuel once
you cleared the planet, you’ll have to take the extra material to eject with
you. Which means you’d have to accelerate THAT mass too.
I’m not sure how a fighter-like space craft using non-“grav-magic”
engines should be able to maneuver in battle. You’d have to calculate the
“maximum delta v without refuel” and take that much dead weight with
you. And if you run out of stuff to eject you’re a sitting duck. (It’s not
fuel in a conventional sense, more like ballast to leave behind)
As for radiation: it’s called “ion drive” for a reason. You *are* in fact
using ionized particles for propulsion. Alpha radiation is nothing other
than high speed ionized Helium particles. Not so different from using
Xenon or whatever.
About “around since forever”: The ancient Greeks knew the concept
of steam engines. And we know that antimatter would be a very
efficient fuel since at least Einstein. And fusion energy has been “just
around the corner” for at least 4 or 5 decades now.
Just because you can formulate a concept that should work, doesn’t
mean you know how to actually build something usable based on
said concept, current ion engines still have very limited use, because
they produce very little thrust and seemed to be working only in the
vacuum of deep space.
I say that because they’ve been around over 100 years but were largely
ignored in that time. Like the areospike engine, they were mostly treated
as an oddity and stuck with the “bell-n-boom” Plus the tech is barely able
get any real performance as yet.
Correct me if I’m wrong, but isn’t “Escape Velocity” the speed you
need to be at when you leave the Earth’s surface in order to coast
the rest of the way out of the Earth’s gravity well?
Like a cannon shell fired straight up from the surface.
The higher a rocket can reach under power, the slower it can be
moving when it runs out of fuel in order to coast the rest of the way.
Technically, you could power your way out of Earth’s gravity well at
a walking pace if you could carry enough fuel.
It doesn’t quite work like that.
Maybe it’s easier to explain if we’re doing it the other way around.
Consider releasing a pebble right “at the edge” of Earth’s gravity well at a
perfect 0 mph relative to Earth.
It would start falling. And falling faster …
By the time it hit Earth it would be doing 11km/s.
So to climb out of the well you’d need to get at least that
much total kinetic energy.
And you can’t allow your vessel to run out of fuel by the way.
At least not if you’re planing on coming back in a controlled way.
Or landing somewhere else.
(Damn am I bad at explaining stuff in a foreign language)
Another way to look at things: hovering just a few meters above ground
(i.e.: your “walking speed” example taken to the extreme) would achieve
nothing but waste massive amounts of fuel because you’d have to accelerate
at one gee, just to hold your position.
In a way the most efficient way to “leave the well” would be the canon shell fired
at 11 km/s because you’d use an EXTERNAL means of propulsion – i.e. one you
don’t have to take with you, one that doesn’t add to the total mass of your craft.
Of course the acceleration needed for that is certifiably un-survivable.
Just to be perfectly clear:
The notion of a “gravity well” is a bit misleading: you’re never quite out of
reach of Earth’s gravity. It’s just that if you get away far enough, the gravity
of other bodies (the Sun usually) becomes dominant.
Since there’s no friction in space you never can stand perfectly still anywhere.
The moment you stop, you start falling towards something. The equivalent to a stand
still is to orbit around something. Earth, the Moon, Sun … whatever.
Using your pebble example, once we had it stationary at the edge of
the Earth’s gravity well, we would only have to move it outward at
walking speed for it to escape.
I fail to see where my example is wrong, you could power your way from
the Earth’s surface to outside of the gravity well at a walking pace,
if you had enough fuel. As I said, “escape velocity” is merely the
velocity which must be imparted near-instantaneously to an object to
let it leave the surface and coast outside of the Earth’s well. It
does not apply to objects moving at a constant pace. They can escape
at any speed, if they have the fuel to move far enough.
In other words, if a space ship leaves the Earth at 100KPH and carries
sufficient fuel to move 1 million K, what’s going to stop it and make
it return to Earth?
Two cases: assuming there’s only the Earth and your craft in the whole wide universe.
In this case you can’t actually leave Earth’s influence, it might be infinitesimal small, but
the pull would still be there. But yes, if you’re far enough out, you might be orbiting at walking
speed. If you slow down to an absolutely perfect stand-still (relative to Earth) you’d drop
straight down, hitting the atmosphere at 11km/s.
As for doesn’t apply for objects moving at a constant pace: to be doing that you’d need to
provide exactly as much thrust as the pull from the planet you’re trying to escape.
If you integrate that (= sum it up) over the course of your flight you’d be at least at the same
amount as if you left in one big blast. There’s no free lunch.
In the real solar system, it is possible to leave Earth’s influence in the sense that the pull from
the Sun becomes dominant by several orders of magnitude. You will then have to be fast enough
to orbit HER – in other words, you’d have to be as fast as a planet as far away from Sun as you.
For example: Saturn is circling at 9.7 km/s and even as far out as Neptune (4.5 billion km from Sun!)
you’d still need 5.4 km/s for a stable orbit (what you called stationary).
But it’s not as much about just dropping back to a planet – if you have enough time to use an efficient
trajectory and can avoid other planets that’s normally not a big problem. My concern is more about
maneuverability.
Just think about the delays involved with “back to reality” spaceflight and try to imagine a battle evolving
at that time scale.
“Captain, there’s a hostile 100,000 miles out.”
“Set course to intercept and wake me same time again tomorrow.”
That is, if you’re lucky and heading at least somewhat in the right direction.
If you’d have to turn around – forget it.
Even as far away from Earth as the moon you’d be doing over 2 miles per
second, you can’t just pull the brakes or you’d drop like rock.
And even if you’d try to stop your craft: that’s a delta v of around 3 km/s
which would require a ludicrous amount of propellant (in a sense that you
can maybe pull it off just a few time before needing to restock).
Any at least somewhat efficient trajectory would probably take you around the
planet.
And even if you’re able to intercept them, boarding would require to adjust your
speeds perfectly to match theirs.
(Forget about “She’s coming about for another attack”, Star Trek-like that would
require delta vs of well beyond taking off of a planet)
Compare that to your own gravity drive. Imperial vessels can basically just zoom
about as they like (ok, yeah, they’d have to get rid of a bunch of excess heat and find
some other mass to pull themselves towards to, but that’s almost trivial in
comparison).
Best example of shooting an object into space was done by accident
during a nuclear test. Now it was never found or any proof of it
exists but, when they did the first underground A-bomb test they
lowered it down a very deep shaft and capped it with a heavy steel
“manhole cover” which was shot straight up and never seen again. A
very basic version Of Jules Verne’s “Man on the moon”.
I think you’re talking about this event here:
https://www.zmescience.com/science/news-science/fastest-manmade-object-manhole-cover-nuclea-test/
It wasn’t entirely an “accident” tho. They weren’t sure exactly how
the sealing cap would deal with the blast. And there’s no prove it
actually made it into space, let alone out of Earth’s influence.
All they got was a single frame from a high speed camera –
so they do have a lower estimate of the speed, but
not a exact number.
Other articles about that same event speculated that the
thingy might have been disintegrated or slowed down below
escape velocity (and burnt up on re-entry).
But all that is just speculation. They never found any part of it.
… it’s Jules Verne, by the way
Me, I prefer to think that the so called “Slug On Pluto” is
actually that same manhole cover that got nuke launched…
Wasn’t too worried about it this is the most time I’ve spent
on the computer since Saturday.