All you need is mass and length of day. Length of day in seconds is the the orbital period of the orbit you're looking for, from there it's pretty easy to calculate the semi-major axis (orbital radius, for all it's worth) based on mass and period.

However, the lack of navigational instrumentation makes this a rather tricky excercise, and if you're patient and carefull, you can get a good enough aproximation to stay over the same spot for a day or two. The hardest parts are getting the orbit circular and getting a close enough to equatorial inclination - Pioneer just doesn't provide the tools neccessary for exact orbital maneuvers. But with engines as powerfull as this, you don't need to bother with them, so this isn't something missing from the game, it's simply outside of its scope. If you want to learn exact orbital maneuvers, Orbiter is the only way to go (correction: Spaceway also provides the neccesary instrumentation, but orbiter is a more learner-friendly environment due to tons of tutorials and a really suportive community).

Again, the technology available in the game doesn't provide a reason for NOT using powered decent. I tried an unpowered decent a few times, but the atmospheric and aerodynamical modeling isn't accurate enough by far to really make it an option, nor would it make much sense. Powered decent gets you down safer and faster.

Set speed mode? That's a bit too much like cheating. (-: I only use it for killing the last of my relative velocity when near an asteroid, or for atmospheric flight.

I use the vis-viva equation and related trig for mucking about with orbits. I have rearranged it so that things I need to know are in terms of things that I do know.

What do I know? I know my current orbital velocity, and my current distance from the thing about which I'm orbiting. Given one full orbit, I know the speed and distance at periapsis and apoapsis, and can work out my orbit's semi-major axis and the "reduced mass" µ, which in a two-body problem involving a big planet and a little spaceship is basically the mass of the planet. I can also measure my orbital period directly.

What else can I work out? I given one full orbit, I can also measure the distance to another orbiting body (if it's in the same plane as me, and in a circular orbit) at conjunction (either superior or inferior) and work out its orbital axis. Using µ, I can work out its velocity, and therefore its orbital period. I can work out a Hohmann transfer orbit, using one burn to enter a new trajectory that will intercept the other body's orbit, timing it so that the body will actually be there when I arrive.

I tried using a slide rule. Although epically hardcore, it just doesn't have the precision (you need about six or seven figures normally, and a good slide rule gives three or four at a push). As a result, I made a spreadsheet copilot that crunches the numbers for me.

A lot of the time, though, I do it by eye. When changing orbits, always thrust along your axis of travel, by which I mean into or away from your velocity indicator. Speeding up slows you down (but makes you gain height), and slowing down speeds you up (and makes you fall in) - orbital mechanics can be counter-intuitive at first.

Landing depends on the planet. I tend to come in at a low angle of attack, because I tend to come in from an orbital transfer or low orbit. This lets me aerobrake if there's a dense enough atmosphere, which means I don't have to worry about killing speed. Interestingly, it's harder to make a descent on an airless world, especially one with high gravity, because you have to kill all your speed yourself. If the atmosphere doesn't slow you, either you have to, or the ground will.

Which Orbiter players call "Lithobraking" 😛

It's called Lithobraking? Funny, I always call it something else when it happens. Usually several somethings. 😎 That sounds a lot better, though.

Good idea for a post, btw. I use autopilot for when I actually want to survive, but manually piloting a spaceship is much cooler than sitting back and hoping the autopilot doesn't decide to spatter you. I think that may have been fixed in the newest alpha, though.

Thanks for the replies. I'll be doing some sums to see what I can see...

I agree that in game we have the technology (i.e. incredible raw thrust) to give us a wide margin of error, but it's nice to enjoy the work that has gone into the planetary gravity modeling.

Too late I remembered the actual reason for this post - when doing short distance deliveries on the same planet (e.g. Brasilia to London) I figure the most elegant way of getting from A to B is a ballistic trajectory.

So...how do do that? Ideally, I'd love an easy calculation but I'm not afraid to plug numbers into a formula...the way I see it, I'd point my craft at my destination, set the ship's attitude to 45 degrees to the horizon, dial up a velocity then go into free fall and enjoy the ride until I reach my destination. The tricky part is working out the velocity for any given planet.

(or maybe it's just me that wants to do this...)

Agreed, but i) I don't know if I'm that keen to immerse myself in that much precision (I got as far as first year maths at uni, and that was 20 years ago {man, it sucks being old enough to say that...}), and ii) from my last check, Orbiter is closed source and Windows only. As I'm running on Linux, both those points make me uninterested.

Oh, you usually don't have to do any math in orbiter if don't want to, the displays do that for you. It's just an incredibly powerfull tool to develop an intuitive feeling for orbital mechanics.

Also, it might be closed source, but it has the best add-on interface I've ever seen. It doesn't come for Linux, though, that is a valid point.

That is a tough one. I think you should get fairly close with standard artillery equations, though, since the acceleration in pioneer is pretty rapid. Precision is still a problem since we have no climb ladder on the hud... Also, I'm not sure at which point Pioneer switches from planet-relative to surface-relative velocity.

Intuitively, (by that I mean, without actually doing any calculations) the planet/surface-relative velocities shouldn't matter. I would expect the relative velocity to the target to be the most critical - that's a number we do have.

Actually, I think the vector relative to the starting point is all you should need, based on the surface distance of the target (a bit of spherical math in there...) But as I said, it will be pretty tough to hit that vector without a ladder and a compass...

Hey, I'll be happy to land within a couple of hundred km. 🙂

Time to brush up on some calculus... 'cos even ignoring the curvature of the planet, it won't be a straight parabola that I'll be traversing...

Ha, I too find this quite fun. It's fun to do everything on manual for the really hardcore. Not much good if you want to get around in a hurry though. I have a very peculiar idea of fun. Bear in mind I also have a degree in Astrophysics, which does help.

Orbit wise, I climb to the height I want and kill my vector with either the retros or by turning around and centering the velocity vector in the rear cross hairs. I then make my insertion burn. Without calculation I make a visual of how much the velocity vector is dropping compared to teh planets limb. If they do it so that the planet always drops away before you crash into it, you rin orbit. I make small burns to esure this on 10x stardreamer.

This is not the most efficient way of doing it (to say the least!), nor the best way to ensure a circular orbit! I'm sure this can be refined and made intuitive though.

You can also widen an orbit by making a burn tangential to the orbit at it's highest point.

This all takes much longer than simple using set speed! It's quite balletic though and saves on petrol. Might take you a few years to get to Mars though if you can work out how to do a Hohmann Transfer Ellipse (that would need maths!) I doubt even the 10000X setting would make that enjoyable.

Still getting the hang of it. Faster = lower orbit Slower = higher. This is counterintuitive. I'm not sure how well pioneer models this, but if you want to go up, in oribtal mechanics you slow down, and vice versa. This is how the shuttle did it. 🙁

Getting down requires careful manipulation of the velocity vector. Since you are never in aerodynamic flight (yet!) you just need to use K and U to reduce your forward velocity and to make sure you don't smash into the planet. Low down it all becomes about little bursts of burn, and using the gravity of the body you are landing on carefully counteracted by the thrusters. This feels very satisfyingly realistic - just like the Eagle in 1969 (though without the terrifying fuel issues.)

Anyway guys thanks for programming this cool game!

s

equations?

brrrr, let's me freeze

no coincidence (half of main thrust for retro), more a resemblance to FE2.

i've made some ships with quite different settings up to the atomic wich has no retro thrusters.

i must say equations can help, but i control a ship intuitive, it will be very important if you have something really lifesize like orbiter, with very limited thrust and a realistic relation between fuel consumption and payload.

but pioneer isn't intented for this imho. so take it as game, it's FUN in first degree.

of course i shoot often over the target, but that didn't matters as long as you have enough propellant left to turn by several times 😉

i stay with uncle bob, some experience and some intuition.

hey, i've got a funny vintage ship for you if you like to travel the universe without a autopilot, i guess it's the next i revive and i will put it on the completed models thread.

it's the odd ADC-44 (alien defense craft 1944), it's leaned on WW2's german "secret X-planes", extremely small, extremely lightweighted, massive overpowered main thrust and very little retro thrust. no or little equipment, i can restrict also the autopilot if you like, but anyway you will have to decide between a laser, a scanner, a radar mapper, a missile, atmospheric shielding or the autopilot, you can mount only one or two of them due to the little cargo capacity.

it's ment that, if you ever have earned enough money, you can mount a military drive and gain a additional tonne of cargo space (a massive gain 😉 )

the setup was also inspired by my experiences with my SW-XWA conversion of the Tie-fighter, i liked to get something like that for pioneer simply.

no life supplyment, extreme acceleration and such (the only thing missing was the screaming sound of it), i also had experienced crazy physics back then with the tie, it's quite a while ago when fighting wasn't that hard like now, i went through a lot of fights, more then one time i was hit just a little bit by the enemy ship on the panels and the tie was hurled through space exactly like in the movie, i loved it.

unfortunately we have a speed limit now 😥 when you fly computer controlled speed in a atmosphere, before you had to be very careful not to get to a meteorite in the sky. i mean already lifting off was difficult and the heat was getting to limit. sometimes i already burned when i lifted off, before i could engage control.

i don't like absolute realism, but i like dangerous things.

that's how commander potsmoke does it 😉

i have had made a second flight, quite better, but unfortunatly due to the fact that i didn't liked to interrupt the flight with savegame states and stopping/starting the recording, the capture file has get to big and couldn't be processed/edited later on.

the idea was to make clear that i didn't cheated or reloaded the game to do it.

it's true i didn't reached a orbit, but this isn't needed with enough powerful engines, orbit is needed for ballistic flights, likewise equations and if you have very limited "amount of propellant / pay load", to reach and land with the "atomic", you don't have to get in orbit, point to the planet and just fire the thrusters not to crash land, that's all.

anyway imo a ballistic flight from one to another body in a system, needs very sophisticated equations, the proper starting position close to equator and the right time window, sometimes even the "professionals" (a whole team) miss and the probes crash or miss the target.

[/hr]

hence, i would like to be able to switch between the old AI and the new, for fights. like somekind of beginners mode and a hard mode.

to let more pirates appear in a target system is easy, i modified the script for this more then once. it worked out fine and i got as a result some systems with no pirates and some with a lot of, but you have to keep in mind that the crime value is a very small number (if that's still the same), with what we have now they almost never appear, needs anyway just a little tweak, if i'm right i once simply multiplied it by 20 and got a good result (0-5 attackers).

but i will have to snoop the actual script and see what i can get out of it now.

i miss a little the bareboned scripts we had before, the result is the same imo, some systems have pirates some no, some missions are reachable some not.

if you ask me that's enough, leave it to the random generator i like that (and i know at least one who likes that to 😉 )

many dependencies makes it complicated (up to impossible) to tweak them for users to their own longings.

i always felt this is something special, even a not experienced could understand what's behind, you don't have to be a programmer neither you have had to know something about that at all, just read the script, think a little while, change a value or two. almost everybody can do this i guess.

but i guess the goal is a bit different now, instead to leave such to the user, it starts to get predestinated to reach... (i don't know).

i really would like if we could get back to the intention of easy to tweak scripts, a few explanations and even a nube can understand how to get more pirates, or how to change the missions.

but perhaps i'm speaking only for myself ❓

i guess not

i guess i'm right if i say that many of the FE2 addicted, did some hacking without beeing programmers, i know that many liked that much, it's a single player game and you can do with it what you like (yes, i remember they enforced you to do so in elite, right?).

well if all fails, there is still a new one with a similar intention (rodina), easy to customize LUA scripts.

and don't forget what is easy for the devs isn't pretty easy for a common user, but changing a value or two, everybody should be able to.

i know this counteracts to what is named "proffesional degree", but users have no "professional degree", usually.

but perhaps they would like to do this and that, or someones posted a weird idea and you like to follow that idea.

to me this was always a important part of pioneer.

with industrial standards you can't do such, all is reserved to the devs, i never would like to reach that.

further i alwas saw pioneer as somekind of tutor or training game, to make the internals of a game understandable for a user, youngsters and children to.

i understand many of the decisions, but likewise the LUA geometry, which i always felt is perfect to teach how the machine does 3D, i mean it has always remind me of the basics i have been teached 30 years ago. mark some vectors, fill the plane with...

but perhaps i'm the only one who looks at this from that pov.

[/hr]

simcity has found it's way to the clasroom.

why shouldn't pioneer find it's way to the classroom?

i'm not bad in geometry and maths, i found out thirty years to late.

it was always such a dry matter, i loved chemistry, because it stinks and sounds

wouldn't it be nice to get maths and geometry closer to the kids, because they can have a cool own ship, made from geometry? (but sorry, with todays CAD you learn nothing about geometry)

to get them the mechanics of spaceflight a little closer, because they can shoot at something?

perhaps if it wasn't that i liked to have a lot of blinking lights on my "millfalc" plastic model, i wouldn't have been that intertested in electronics.

or if it wouldn't have been cool to have a simple synthesizer where you could slide with your finger along a drawed graphite line and make crazy noises.

what would have told me what a VCO is and how it's coupled with a LFO...

A true Hohmann transfer orbit from Earth to Mars takes 259 days, although there are many similar solutions which take advantage of the non-circular nature of Mars' and Earth's orbits which can shave a good month off that. It's certainly not years! At the maximum 10,000x acceleration that should take nearly 40 minutes of real time. Long enough to be upset if you screwed up the launch burn.

Which is easy to do, since you leave Earth's frame of reference some time after you start your journey, and that reference frame isn't rotating once a year as it orbits with Earth. So, you start off with only Earth's gravity curving your trajectory, before switching to only the sun. This has the subtle effect of making your transfer orbit swing out wide, causing you to miss Mars. It doesn't really matter how good your maths is, you're going to have to do some correction on final approach.

can't we simplify the whole thing a bit?

i doesn't mean the prev. reply, i mean the whole thing...

is it really needed to make all perfect?

don't you think gameplay isn't much depending on all this sophisticated stuff?

as stupid comparison,

i sure like to have sometimes high detailed models, i wouldn't say i'm a perfectionist, but of course i would like to make it perfect sometimes.

i like animated things much, if it was only my pleasure i would animate i don't know what, people running around, "flying cars", perhaps animals or wiggeling trees

that's TOO MUCH! no one has to tell me that.

i have a simple limit or barrier i have to follow, polycount and framerate.

besides of that it isn't needed for a good gameplay, it's a candy i would say.

so i always keep the models in some boundaries.

yes, i made some different ones, let's say to satisfy my longings, e.g the "Bloodrunner", with various analogue clocks, lot of ancient looking computers with countless flashing lights, plus a little planetarium (cancelled for the new bloodrunner), this is already TOO MUCH.

it's ok as a little extra and to satisfy my pleasure in modeling, but it's not needed to have such for the game, really not.

after the bad example, the good one

the Typhoon looks cool imo, but is held as simple as possible, i also waived textures mainly to keep it smoother running, therefore it can have a animation or two more.

i guess we should keep the whole game in some reasonable boundaries, should look good

BUT should be fun to play

i miss the PLAY...

[/hr]

again i refere to the "nova" rodina, this guy has touched my heart, why?

"graphics arn't important for gameplay"

of course it's a part of it, but not more.

likewise all that tech stuff isn't really important.

perhaps that satisfies the devs likewise a cool animated model satisfies me.

but i really like to play and i miss that a lot.

i don't think it's important to know how to reach a orbit, this is pioneer not orbiter we are working on.

it's a game with the core idea in trading, doing missions and fighting.

which is "occasionaly" happening in space, that's all.

it could be also trading, doing missions and fighting with windjammers, or a team of adventurers, whatever you like.

it's still the same, only the "names and places" change, imho.

all of that is missing, i think it's time to work on that.

[/hr]

i ask that again, why is asteroids still addictive?

certainly not because of graphics

neither it offers any degree of realism

but it's a good gameplay, action and the challange for the player to reach the next level

stupid yes, but it works

at least, i play such games sometimes, and actually if i like to have some action i won't play pioneer, no i will dig out one of those 80's games and get sweatin' all over

i rember when i first played frontier i was sweatin' all over too, I LIKE TO GET SWEATIN' ALL OVER WITH PIONEER!

i wanna be such wet that i get crumbled skin, man!

[/hr]

i was told more then once, that if i like older releases better i'm free to do so...

yes, two years ago we had more gameplay

- some simple missions

- a beatable AI

- a already working trading system

all this has been delayed, for?

- better looking terrain

- cities that won't look like out of a peppershaker

- a lot of graphical enhancement's

i wouldn't say i didn't like that

but it's not needed,

i was pleased with the terrain

i was pleased with the cities

i havn't mind about textured stars, or how such appears at all, more or less.

i guess i will be pleased to fly a "shoebox", if i can do something, if i can shoot at something, if i can do some trading or fulfill a mission.

past winter i played for a month or so good old (amiga)FE2, it's far more fun rather pioneer, the graphics are low compared to todays standards, but the game still is addictive.

sorry for my hard words, but that's what i feel and additionally i feel i'm not alone with that.

[/hr]

following i tell here for the first time, but it reflects my fears to 100%

sometimes when i look at the slow progress (yes, you have done a lot of work, but i feel we got stuck)

sometimes it appears to me like we have intruders from another project in pioneer who like to delay all.

i know this is offense of me, but these are my fears.

i can only hope i'm completely wrong with that fear.

[/hr]

no, i don't like to step back, neither i like to split,

further i don't like to wait until "sankt nimmerleins tag"

[/hr]

another comparison with my work on the models.

sometimes i have made models far to complicated, i know that by myself, but i also knew that i can easy step back and simplify them here or there.

it's no big deal and i costs me no blood.

@potsmoke66

I might have worded it differently, i.e. shorter 😀 but I agree with your general argument.

You build a game to play, not to look at, and I'm as guilty of doing this myself but we're spending all our time and focus on the look and not the play lately.

Since I joined the project there's always been discussion of the "plan for factions", factions naturally lead to conflicting interests, missions, etc.

That sort of pseudo-goal driven gameplay is lacking at the moment and I think I've been here for over a year now.

Think I might start another topic for this.

Andy

@fluffyfreak

"der apfel fällt nicht weit vom stamm"

means, i'm like my daddy.

i have a relative who has made a obituary when he died two years ago.

in (i hope), short terms, my father was someone who started in stoneage when he tried to explain something.

or in his words:

"when he starts to talk about liberation war in switzerland (13th/14th century), you never knew if he wouldn't go to the basement to dig out his armor". :ugeek:

btw, i'm german not swiss, that makes it also sound a bit weirder, i hope.

your'e not guilty of no charge

it happens to me too, we like to present our strengths, that's all.

259 days? Of course, makes sense, your only doing half an orbit really. Has been a while since I did that stuff! I think though that should be err... left as an exercise to the sufficiently motivated.

Gameplay wise, yes the scenery is awesome (though less awesome than previous builds? I'm new as of Alpha 21.) I'm looking very much forward to cool stuff happening....

I have to say I'm glad this is out there. I've been waiting years for the Infinity guys to get something out there - but this is actually available in the here and now and is only going to get better. I just wish I had the time & expertise to pitch in.