WIP Discussion (Part 1!)

[GeoModder]

That's Rosanrer-Rotor to you.

Mmm... Rotor isn't to be found in the Trade lexicon, so I'm unsure whether or not I was soshrallal with my remark.

[Arioch]

That's Rosanrer-Rotor to you.

Mmm... Rotor isn't to be found in the Trade lexicon, so I'm unsure whether or not I was soshrallal with my remark.

It's "seven." It's in the numerals section but for some reason the numbers weren't all included in the recent lexicon dump.

Small craft usually don't get unique names, so they're typically identified by the type name and a numeric designation, so "Highland-Seven," "Arrow-104," etc.

[icekatze]

hi hi

It is true that Alex, and ourselves as the readers have already been briefed on what is going on. Still, Tempo makes it sound routine and unremarkable, but seeing it in action gives it a sense of immediacy. Routine may well be intense for the Loroi, but it still makes me wonder about the situation.

The Frigate Clearbrook, is it not part of the 51st strike group? I assume it wasn't, but I don't know for sure. (If we were told somewhere on the forums, I've forgotten.) If it was part of the 51st, I would think that they'd have made the transfer when they decided to split up, rather than when they were already far apart, unless the decision to offload Alex wasn't made until later.

If the Clearbrook wasn't part of the 51st, I guess that brings up other questions about who is in command on the other side, and if that commander has different methods than Stillstorm when it comes to strange aliens who may or may not be Umiak tricks.

[JQBogus]

Depending on how the Loroi military organizes itself, it is possible that the Clearbrook is part of the 51st Strike Group, but just not part of the strike element.

[Arioch]

The Frigate Clearbrook, is it not part of the 51st strike group? I assume it wasn't, but I don't know for sure. (If we were told somewhere on the forums, I've forgotten.) If it was part of the 51st, I would think that they'd have made the transfer when they decided to split up, rather than when they were already far apart, unless the decision to offload Alex wasn't made until later.

Clearbrook is one of the escorts from the supply convoy, which arrived from the direction of Azimol. Strike Group 51 arrived from Sala 128 (from the direction of Naam) on the opposite end of the system. Clearbrook has been diverted toward the vector to Gora (which is the beginning of the leg path to Seren), which is essentially perpendicular from the Azimol-Sala 128 path, and the Highland shuttle was dispatched to catch up with Clearbrook and transfer its passengers before she jumps to Gora. Meanwhile, SG51 and the convoy are matching velocities nearer the center of the Leido system so they can refuel and resupply.

[Krulle]

One would have to be extremely close to the sun in order for solar wind to have a significant impact on the drive plume of a ship. At 1 AU, the pressure is measured in nanopascals.

And the particles which actually make a drive plume visible are extremely tiny and light.

As any tail of a comet will show you, the pressure of the solar wind at 2 AU is more than sufficient to blow such things away.

Let me wiki a bit.

Found a remark, and it's even more than I thought.

ion tails have been observed to extend 3.8 astronomical units

If the ion tail gets 3.8 AU long, I assume being within the range of the inner planetary system will blow the drive plume away from the sun. (Jupiter is at 5,2 to 5,4 AU from the sun).

Apparently, also Venus has it's own ion tail.

[GeoModder]

That's Rosanrer-Rotor to you.

Mmm... Rotor isn't to be found in the Trade lexicon, so I'm unsure whether or not I was soshrallal with my remark.

It's "seven." It's in the numerals section but for some reason the numbers weren't all included in the recent lexicon dump.

Small craft usually don't get unique names, so they're typically identified by the type name and a numeric designation, so "Highland-Seven," "Arrow-104," etc.

Ah, okay. Thanks for the explanation.

[icekatze]

hi hi

As any tail of a comet will show you, they take days and weeks to form. By then, anyone who is trying to observe a drive plume will have already had plenty of time. Gasses might accelerate up to as fast as 0.6 km/s with repeated interactions inside the tail cloud. (And it is also worth noting that the ion tail is only a fraction of the mass in a comet's tail.)

Comets


((Those star maps are looking more complex. Probably on account of 3 dimensions, I suspect.))

[Karst45]

http://well-of-souls.com/gallery/images ... n_2015.jpg

One of these days...

My wish for a Stillstorm pinup will be granted...

I could also settle for an Ashrain one how about a pillow fight between stillstorm and Ashrain?

[Hālian]

Because then we would have the first known successful use of a pillow as a murder weapon.

[Mjolnir]

As far as I'm aware, in the vacuum of space, an exhaust plume will look exactly the same regardless of orientation or current velocity. In the comic, the plumes sometimes bend to indicate change in trajectory, but I think that's more visual convenience than strictly realistic.

Like a big water sprinkler...but as high as the exhaust velocity is going to be, probably only visible on sensors at a scale where the ship is a pinprick.

One would have to be extremely close to the sun in order for solar wind to have a significant impact on the drive plume of a ship. At 1 AU, the pressure is measured in nanopascals.

And the particles which actually make a drive plume visible are extremely tiny and light.

As any tail of a comet will show you, the pressure of the solar wind at 2 AU is more than sufficient to blow such things away.

The drive plume of a ship accelerating at 40 g is not going to behave the same as a cloud of ionized gas being stripped away from a chunk of slowly sublimating ice.

[Absalom]

I've been looking through NASA articles about plasma, fusion, ion & other thrusters for their future spacecraft, does anyone have any opinions on which is going to be the thruster of the future? Anyone else geeking out over all of this amazing sci-fi space ship tech becoming reality?

Different drives for different purposes. Ion/Hall Effect/etc for distances & long-term station keeping. Plasma for high-thrust tasks, but only if you have a major power source: they're a decent choice if we need Earth-orbit space tugs. Fusion is firmly in the realm of future-tech: non-self-sustaining is just a revision of plasma, and self-sustaining is not possible with current technology. The EmDrive could be an interesting alternative to the Ion drive category, but the tests have always been on the edge of detection.

Has anyone seen any technological breakthroughs concerning artificial gravity, inertial dampeners, or radiation shielding? You know, the technologies that would allow us to explore the solar system unhindered by the current hurdles.

For charged particles you can always play with magnetic fields, but otherwise your best bet is hydrocarbons (or water, if you don't mind hideously expensive launches). Artificial gravity and inertial dampeners will hopefully become available via manipulation of the Higgs field, but that's so far beyond future-tech that it's daydream-tech.

For long travel distances, if no FTL shortcut is found, photon drives will be the only viable solution. But they have a terrible low output, but by far the best propulsion/energy ratio.

Fusion is supposed to be decent if we can ever get a net-positive fusion reactor. There's also the old Orion Drive proposal, some variations of which are actually plasma/fusion drives themselves (MicroMagOrion, or something like that).

Fusion is an energy creation process, not a drive system. The ions, plasma, ... can be created using fusion...

"Leaky" fusion is a suggested form of plasma drive.

[Arioch]

Fusion is an energy creation process, not a drive system. The ions, plasma, ... can be created using fusion...

"Leaky" fusion is a suggested form of plasma drive.

That's the drive used by the Moties. "They're just enclosing the hydrogen, fusing it and blasting it out. A plasma bottle."

[Krulle]

For long travel distances, if no FTL shortcut is found, photon drives will be the only viable solution. But they have a terrible low output, but by far the best propulsion/energy ratio.

Fusion is supposed to be decent if we can ever get a net-positive fusion reactor. There's also the old Orion Drive proposal, some variations of which are actually plasma/fusion drives themselves (MicroMagOrion, or something like that).

The problem is that the mass of the fuel is lost afterwards, and that we therefore need to put tremendous amounts of fuel on the ship. The distance (without FTL) is prohibitively large, the amount of fuel needed therefore tremendous, so much even, that most calculations I've seen so far suggest starting the ship, and sending the crew to it more than 10 years later, to catch up with the ship when it is somewhere near Jupiter for the first sling shot (or even catch it between Jupiter and the Sun for the big slingshot).
The amount of fuel will make the non-FTL interstellar ship so massive, that the acceleration will be near non-existant when it still has enough fuel to brake with 1g when the ship has reached one of our closest neighbours.

That's the drive used by the Moties. "They're just enclosing the hydrogen, fusing it and blasting it out. A plasma bottle."

Oh, great... :p Another book I need to get my hands on and read.
Thanks! (and I mean that sarcastically and honestly at the same time. I love reading SciFi, but have absolutely no time currently for private hobbies like reading a good book).

I also need to read it as the Moties sound a bit like the Thraddash from Star Control 2/ The Ur-Quan Masters.

[Sweforce]

For long travel distances, if no FTL shortcut is found, photon drives will be the only viable solution. But they have a terrible low output, but by far the best propulsion/energy ratio.

Fusion is supposed to be decent if we can ever get a net-positive fusion reactor. There's also the old Orion Drive proposal, some variations of which are actually plasma/fusion drives themselves (MicroMagOrion, or something like that).

The problem is that the mass of the fuel is lost afterwards, and that we therefore need to put tremendous amounts of fuel on the ship. The distance (without FTL) is prohibitively large, the amount of fuel needed therefore tremendous, so much even, that most calculations I've seen so far suggest starting the ship, and sending the crew to it more than 10 years later, to catch up with the ship when it is somewhere near Jupiter for the first sling shot (or even catch it between Jupiter and the Sun for the big slingshot).
The amount of fuel will make the non-FTL interstellar ship so massive, that the acceleration will be near non-existant when it still has enough fuel to brake with 1g when the ship has reached one of our closest neighbours.

That's the drive used by the Moties. "They're just enclosing the hydrogen, fusing it and blasting it out. A plasma bottle."

Oh, great... :p Another book I need to get my hands on and read.
Thanks! (and I mean that sarcastically and honestly at the same time. I love reading SciFi, but have absolutely no time currently for private hobbies like reading a good book).

I understood it that photon drives are weak NOW and still useful. I doubt that there isn't possible to make powerful versions as well.

With FTL, at least for space travel stories I would point to the Alcubierre drive. In the Outsider verse the Alcubierre could represent humanities first attempt to reach the stars first theorised in the late 20th century and eventually a research test rigs could be made. For a story I would go for a more then a century old Alcubierre test rig somewhere, operational but not to a useful degree other then another tool for the scientists in their research. From time to time they add some new parts to it and remove some old junk but it is essentially the same experiment worked on when time and funding permits. What they lack is enough exotic materials and and antimatter to build and fuel a upscaled experiment. Both manufacturable but in nowhere near the quantities needed and the invention of the jump drive killed most of the founding anyway.

Still this may by why the historians ships use reaction less drives.

[Mjolnir]

For long travel distances, if no FTL shortcut is found, photon drives will be the only viable solution. But they have a terrible low output, but by far the best propulsion/energy ratio.

Fusion is supposed to be decent if we can ever get a net-positive fusion reactor. There's also the old Orion Drive proposal, some variations of which are actually plasma/fusion drives themselves (MicroMagOrion, or something like that).

The problem is that the mass of the fuel is lost afterwards, and that we therefore need to put tremendous amounts of fuel on the ship. The distance (without FTL) is prohibitively large, the amount of fuel needed therefore tremendous, so much even, that most calculations I've seen so far suggest starting the ship, and sending the crew to it more than 10 years later, to catch up with the ship when it is somewhere near Jupiter for the first sling shot (or even catch it between Jupiter and the Sun for the big slingshot).
The amount of fuel will make the non-FTL interstellar ship so massive, that the acceleration will be near non-existant when it still has enough fuel to brake with 1g when the ship has reached one of our closest neighbours.

A Jupiter slingshot will add nothing significant to a ship on an interstellar trip...at most 13 km/s. Rendezvous with an outbound starship is probably not practical...the ship leaving later will need much more delta-v to catch up and then stop when it reaches the first ship. And I don't know how to parse the bit about acceleration being near nonexistent when it's 1 g.

Unless you have the ability to convert most of your fuel to energy, the fact that the mass of expended fuel is ejected is a good thing. You don't want to keep hauling the end products of fusion around, and you may as well use the mass to produce thrust as you dump it overboard. This is the major problem with photon drives, there's no good way to fit the required energy aboard, apart from hauling huge amounts of antimatter around. Unless we work out a way to convert normal matter directly to energy with high efficiency, photon drives will require antimatter (or be limited to niche uses, such as things like fine positioning of components of an orbital interferometer).

The most practical form of photon propulsion is really the laser sail, which produces twice the thrust for a given amount of power, but more importantly, doesn't have to haul the power plant around. A high efficiency fusion drive would also have the performance required to reach nearby stars within a century or two. A combination using photon sail propulsion for departure and fusion for braking might be the most practical approach.

Once you have something at the destination, you've got other options for braking. The first thing you deliver should probably be an automated factory to set up laser stations or similar infrastructure for braking later spacecraft.

[Krulle]

The amount of fuel will make the non-FTL interstellar ship so massive, that the acceleration will be near non-existant when it still has enough fuel to brake with 1g when the ship has reached one of our closest neighbours.

And I don't know how to parse the bit about acceleration being near nonexistent when it's 1 g.

I forgot (or accidentally deleted) the "at the start of the mission" after "acceleration".
Due to the mass of the fuel, the ships start with 0,000something g until so much fuel has been burned that the mass has been reduced that the engine can actually achieve 1g.
The output of the engine is the same, but the mass it has to accelerate with the output is getting less and less over time, so the acceleration the engine can achieve increases.
Current engine technology, including forecasts in engine efficiency increases, don't foresee us coming into practical ranges within a few decades. If you make the engine large enough to achieve 1g at the start, with the tons of fuel you're hauling around, the engine is mostly dead weight towards the end of the journey (meaning you'll need even more fuel than forecasted to brake your ship, or you'll need to ditch 99,99999% of your engines). If the engine is made to achieve 1g at the end of the journey, the engine is too small to actually make the ship leave the solar system at the start of the voyage (i.e. you won't reach escape velocity of the solar system).

It all comes down to one thing: without FTL we will be confined to the solar system, except for "we pull together because we want Humanity to reach for the stars and thus we pay for it together" missions, which will even then likely be confined to highly automated science missions and possibly one token colonisation mission, as the drain on Earth's economy will be gigantic, without any foreseeable return of investment.

We might be lucky enough that our grandkids are alive when earnest mission planning starts.... (I dream of a different timetable, though).

[Arioch]

That's the drive used by the Moties. "They're just enclosing the hydrogen, fusing it and blasting it out. A plasma bottle."

Oh, great... :p Another book I need to get my hands on and read. Thanks! (and I mean that sarcastically and honestly at the same time. I love reading SciFi, but have absolutely no time currently for private hobbies like reading a good book).

I also need to read it as the Moties sound a bit like the Thraddash from Star Control 2/ The Ur-Quan Masters.

It's one of the true classics of science fiction -- a must-read.

[icekatze]

hi hi

Having a poor starting thrust is what staging is for. You have a booster stage at the start, and it decouples once it is spent.

[Mjolnir]

Having a poor starting thrust is what staging is for. You have a booster stage at the start, and it decouples once it is spent.

That is the answer for most rockets. For an interstellar journey, you don't gain much...you're not really in a hurry to finish your burn, since you'll likely spend most of your time coasting anyway. The slow start might be unimpressive, but it's still momentum gained.

You might still need staging of some sort, but more for shedding excess structural mass that's no longer needed for carrying propellant and for shedding worn-out drive equipment, if you need anything that can't be repaired/rebuilt/recycled mid-flight.