[WIN] Flyby Finder for Real Solar System Mod V0.85 [RSS12.0 for KSP1.2.2]

[NathanKell]

Dunno why I didn't think to do this before, but I added a link to this in the RSS OP.

[PLAD]

Dunno why I didn't think to do this before, but I added a link to this in the RSS OP.

Oh wow, right near the top, too. I am glad you like it, RSS is a superb mod and I am in a bit of awe over the amount of work that must have gone into it.

[NathanKell]

Thanks!

(And yeah, it's...been quite a timesink, that's for sure! Though a fun one. )

[PLAD]

Just a note I've posted an update to FFRSS, now it's version 0.82. This version is strictly a bug fix, I eliminated those pesky false positives that would appear in extremely high-energy regions (usually hyperbolic) of the charts. It also allows some true positives through that were blocked before in paths that go from one gas giant to another. In case you're wondering, version 0.81 filtered out all false positives with a vengeance, in fact it also filtered out too many true positives to be acceptable, once I had the revelation for 0.82. I'm now satisified with the Lambert algorithm, and it's on to another shot at double flybys.

I also updated the Lambert spreadsheet a bit.

[BevoLJ]

Thanks for the update, and good luck on the algorithm! =)

[Ice30]

Thanks so much for this application it seems like a lot of fun to use!

I am sorry to report I am having difficulty planning a fly by of Venus -> Mars. I managed to plan a route using the application with the following stats

Start Planet: Earth

Orbit Departure Time:

69724800 seconds UT

808 days UT

18 Mar 1953

Y3 D78 H0

Start Orbit Inclination: 55.3 degrees

Start dV: 3802 m/s

Start Equatorial Z velocity: 9530 m/s

Start Equat. Prograde velocity: -1191 m/s

V Infinity Leaving Start Planet: 3728 m/s

1st Encounter Planet: Venus

Time from Start to 1st Encounter: 165 days 0 hours

Vinf in: 7696 m/s

Brake to Orbit?: 5523 m/s

1st Encounter Periapsis:

973 days UT

30 Aug 1953

Y3 D243 H0

379 km altitude

Vinf out: 7696 m/s

2nd Encounter Planet: Mars

Time from 1st to 2nd Encounter: 150 days 5.2 hours

Vinf in: 9770 m/s

Brake to Orbit?: 7460 m/s

2nd Encounter Periapsis:

1123.22 days UT

27 Jan 1954

Y4 D28 H5.2

Total delta V expended: 11263 m/s

Total Travel Time: 315.2 days

I set up a dummy spacecraft with a prograde and normal as indicated in the calculator, however the alignment with venus seems to be out of phase by about 10-20 degrees. Could this be a false positive or am I just using the application incorrectly?

Thanks in advance as I am keen on getting this working!

[PLAD]

Thanks so much for this application it seems like a lot of fun to use!

I am sorry to report I am having difficulty planning a fly by of Venus -> Mars. I managed to plan a route using the application with the following stats

I set up a dummy spacecraft with a prograde and normal as indicated in the calculator, however the alignment with venus seems to be out of phase by about 10-20 degrees. Could this be a false positive or am I just using the application incorrectly?

Thanks in advance as I am keen on getting this working!

OK, I set it up and it worked right- leave Earth on Y3 D78 at Vz 9530m/s, V prograde -1191, 165 days to Venus periapsis, and with a small tweak I got close to the Mars encounter at day 315. (I can't set up the Mars encounter exactly, because from deep in the Earth's gravity well a .01m/s change makes for a million km shift at Mars). However, the path goes through the Moon's SOI. This makes the path vary oddly as you shift time, could that be what's happening? Also, which version of RSS are you using? I haven't installed and tested RSS 10.3.1 yet. I checked the change log and the RSSKopernicus.cfg file and haven't found any changes that would cause such an error, but there's nothing like running it.

As a general aside, when I set the Vz and V prograde and start shifting time I often get more than one 'hit' where the path enters the target SOI, but only one of them will have the right travel time, if a hit doesn't have close to the right travel time keep shifting the departure time until you find one that does.

-PLAD

Javascript is disabled. View full album

[Ice30]

Thanks for your efforts in trying to replicate the problem. Comparing your screenshot to mine it seems like the planets are in different locations...

I'm pretty sure I am running this version of kopernicus:

https://github.com/Kopernicus/Kopernicus/commit/f72f804539c98c49a827b30487c2348fd38f5d64

I had to switch to this version rather than the latest because the latest version caused some instability\conflicts with my setup.

Everything else is up to date using ckan

If it's a simple matter of the time stamp being out by a certain amount, is it possible to find out how much I need to offset my dates?

EDIT

Hm cant get my imgur to display... Here's the URL

http://i.imgur.com/zWOTVIf.png

Edited November 9, 2015 by Ice30

[PLAD]

Thanks for your efforts in trying to replicate the problem. Comparing your screenshot to mine it seems like the planets are in different locations...

I'm pretty sure I am running this version of kopernicus:

https://github.com/Kopernicus/Kopernicus/commit/f72f804539c98c49a827b30487c2348fd38f5d64

I had to switch to this version rather than the latest because the latest version caused some instability\conflicts with my setup.

Everything else is up to date using ckan

If it's a simple matter of the time stamp being out by a certain amount, is it possible to find out how much I need to offset my dates?

EDIT

Hm cant get my imgur to display... Here's the URL

http://i.imgur.com/zWOTVIf.png

OK, the picture of the planet positions on what your system says is Y3 D78 solves everything. It was totally different from what my system shows on that day. (And I used a fresh-everything install of RSS 10.3.1, I had to update anyway!) I took a new save starting at Y1 D1 and ran it until the planets were in the same position as what you show in your picture. I put a third picture in the album above to show when it was- Y1 D237. Then it hit me.

If you go to the main settings in your install I think you will find this: "Displaying Kerbin Time-(6 h days, 426 d years)". You want to change that to "Displaying Earth time...". Y1 D237 in Earth time is the same as Y3 D78 Kerbin time.

I have mixed those two time systems up several times. I wish there was a different name for the Kerbin "day". We call it a "Sol" on Mars, for instance. In any case, happy trails!

[Ice30]

OK, the picture of the planet positions on what your system says is Y3 D78 solves everything. It was totally different from what my system shows on that day. (And I used a fresh-everything install of RSS 10.3.1, I had to update anyway!) I took a new save starting at Y1 D1 and ran it until the planets were in the same position as what you show in your picture. I put a third picture in the album above to show when it was- Y1 D237. Then it hit me.

If you go to the main settings in your install I think you will find this: "Displaying Kerbin Time-(6 h days, 426 d years)". You want to change that to "Displaying Earth time...". Y1 D237 in Earth time is the same as Y3 D78 Kerbin time.

I have mixed those two time systems up several times. I wish there was a different name for the Kerbin "day". We call it a "Sol" on Mars, for instance. In any case, happy trails!

Brilliant! Thanks mate - I didn't even realise I had to set that, I thought it was automatic with RSS. Thanks for your help and thanks again for the application!

[Unit327]

On 23/8/2015, 7:37:47, Wobulator said:

Is this linux compatible? I'd imagine that the majority of RSS/RO players use linux

I managed to run this via playonlinux (wine frontend). A native version or even a web based one would be great though.

[PLAD]

I travel to the Moon a lot in RSS/RO, so I made a little spreadsheet to find the best time to launch with a due East azimuth from sites that have a latitude larger than the Moon's orbtial inclination of 28.36 degrees.  It can be used for lower-latitude launch sites with a caveat, see below. I've put the Dropbox link in Flyby Finder for RSS's (this thread) first post. A small album showing what it does is here. It only works for Earth's surface to Earth's Moon using RSS for KSP. The summary below is rather long, sorry about that. It is an exercise in spherical geometry, the advantage of the spreadsheet is you can see how I do it, step by step.
Summary:
Only change the cells in green!
Input the desired search start time. Usually this would be the current time in your game. Then input your desired travel time from launch to Moon periapsis. The sheet will look for the 2 launch windows in the 24 hours after the search start time, that will arrive at the Moon at exactly (search start time)+ (minimum travel time)+1 days.
Enter your launch latitude and longitude in degrees, note the format, for instance Canaveral is longitude -80 degrees or +280 degrees East, never degrees West. Southern latitudes are negative. I've written some real site locations down in the spreadsheet.
The launch LAN fudge factor is trickiest. The sheet computes the LAN of the orbit you need to get into, and knows when your launch site will cross the plane with that LAN. But because you launch with the sideways motion of the Earth's surface your LAN will increase as you are ascending, and the amount of this increase depends on your launch profile, the acceleration of your ship, and your launch latitude. I've found values between 5 and 8 degrees work for most ships. You can figure it out by turning on the LAN indicator in Mechjeb and watching it change from launch to orbit. Every degree in LAN error causes about a 2-hour change in your arrival time at the Moon.
The outputs are the two launch times in the 24 hours after the search start time at which you can launch due East and get to the Moon with a prograde-only TLI burn, with the flight time being between "minimum travel time"  and "minimum travel time" +1 days. You have to figure out the TLI time and burn magnitude yourself but that is easy by just shifting the burn execution time around. From a 200x200km orbit and a 3 to 4 day flight time the TLI burn should be between 3120 and 3190 m/s.
The nominal arrival time at the Moon is also given, along with the distance of the Moon from Earth at that time (smaller makes for quicker or lower-dv flights), the Moon's latitude at arrival time (useful for anticipating your re-entry latitude when returning to Earth) and the latitude on the Moon where the Sun will just be rising when you arrive, useful if you wish to land just after local sunrise like Apollo did. Note that sunrise is only accurate for the Moon's equator, the RSS Moon has seasons just like Earths (unlike the real Moon), if you are far enough North or South the Sun doesn't rise at all for extended periods. (This is a result of the KSP engine and RSS can't change it). I'm thinking about giving the 'season' of the Moon's North pole at arrival, but it will be the same as Earth's season so you can just look at the time of year (day 1 is January 1st) and guess it.
Note that this program can work for launch sites close to the equator, but only of you will arrive at the Moon when it is closer to the equator than the launch site (which it is sure to be at least twice a month!). You can also launch straight into the Moon's orbital plane from near-equatorial sites but you will have to figure out those times on your own. Those will not be due-East launches, and this spreadsheet only finds due-East launch flights.
This is all practice for defining the best launch time to get to flyby departures, which is a similar problem.

Edited January 1, 2016 by PLAD

[vjcolt]

Thx for this, but you can look at KSPTOT

And see if you can add algorytm from this tool for double fly-by.

[CitizenVeen]

Looks like a nice planner! Several things I dont understand though:

1. what is Vz?

2. Your planner doesnt suggest an angle to prograde point where to start the manouvre, is that correct?

3. Youre planner, after start dV, names "start equatorial Z velocity", "start equat. Prograde Velocity" and "V infinity Leaving start planet", what are these?
I figured that the first 2 were how much dV I had to burn into either nominal or prograde, however, they dont add up to get 'start dV' value, so I guess i must be wrong. And what is V infinity?
 

I tried to google all this, but couldn't find it.

I guess what I am trying to say is: I am utterly failing to understand anything of your planner. I am using mechjeb manouvre node editor to make sure i enter the exact right values. I read your instructions text that comes with the download, but made me non the wiser. How do I translate the data I get out of your planner to make a manouvre in game that works?
Sorry for my stupidity, help is much appreciated :).

[PLAD]

Hello CitizenVeen,

   It is true that the text that comes with the download is pretty light on details. The Imgur album guides in the FF for RSS guide (in the very first post in this thread) answer those questions with a lot of details though. Here are the parts relevant to your questions.

FF assumes you have a test spaceship in orbit around the start body (usually Earth) in an equatorial, circular orbit at the "boost altitude". I Use Hyperedit to put it there. You will never actually fly away in this ship, it is just there to show you the orbit you need to launch into. In the example below I want to launch from Earth and flyby Jupiter to get to Saturn. After some searching around I have decided I want the flight that is highlighted in Blue. What is called "start vZ" in the column on the left is called "start Equatorial Z velocity" in the detail panel on the right. It is the number you will enter in the Mechjeb (or precise node if you use that) field called "Normal +" that you see in the 2nd picture below. "Start equat. prograde velocity" is the number I will enter in the Mechjeb field called "Prograde" in the 2nd picture below.

  You are right that I do not suggest an angle to prograde. My approach is to have the user enter the start equatorial Z and prograde velocities into a manuever node placed on the test ship and then use "shift time" from Mechjeb to find the spot from which you need to execute the departure burn. I do this because even if you start with a suggested angle to prograde you will still have to adjust the start time from there until you find the exact spot. So I just start with the shift time at maybe 200 seconds and keep hitting "+" and "-" and watch the predicted path until it is close to hitting the target planet at the desired time, then cut the time step to about 10 seconds, then finally 1 second to zero in on the exact start time.

"V infinity leaving start planet" is the speed your ship will have just before it leaves the SOI of the start planet. It is used as a check that your ship has the right energy at that point. The other "Vinf in" and "Vinf out" fields give the speed you should have just after you enter the SOI of a planet and just before you leave the SOI of a planet. They are also just safety checks that all is well. I could remove those fields and you could still fly the mission without knowing them, though if you do a lot of correction burns you might change your speed considerably and by comparing to the desired v infinities you might catch the problem early. In any case, here are the pictures.

 

1st picture: the most important numbers are the start equatorial Z and prograde velocities.

 

2nd picture: I have entered those two numbers in the correct fields in Mechjeb's manuever node editor, and then hit 'shift time' back and forth until I saw the flight Earth-Jupiter-Saturn.

 

3rd picture: This shows what the correct departure orbit looks like. The blue line is the circular, equatorial, 200x200km orbit of the test ship. The dotted yellow line shows the departure orbit that I will have to launch my ship into. I know it is inclined -32.4 degrees from the "start orbit inclination" that FF gave. My real ship is sitting on the launchpad at Canaveral, I must now wait until the Earth rotates Canaveral into the plane of the departure orbit. and then launch. Then I have to set up the maneuver node again for my real ship, but since my real ship will be moving on the right plane to start with (hopefully!) the maneuver will only have to be the "start Boost" entered into the "Prograde" field of Mechjeb. Radial always stays at '0' and normal will be '0' if your ship is exactly in the right plane. (Start boost is 6530m/s in this example.)

 It is hard to launch exactly into a line shown on the screen like that. I am trying different ways to indicate the best launch time but have some problems. The best I've come up with so far is to give the LAN of the desired start orbit, then sit at Canveral with Mechjeb's  "Orbit info" page open, because Mechjeb gives the LAN of your ship even as it sits on the ground. The huge problem with that is that the indicated LAN at launch will be lower than the actual LAN once you are in orbit due to the variable nature of the ascent path.

 In any case this is what the info that FF gives out means. I've found the most important thing of all is the times of the launch and flyby periapsis, if you get those right everything else will follow. So for instance the example above says to leave Earth on Y24 D135 H0 and flyby Jupiter at Y26 D135 H0. If you get that right you should be able to make a small adjustment to your Jupiter (best is to do the correction 90 degrees before your Jupiter encounter) flyby to get flung to Saturn. In the example you might notice that my actual flight time E-J is 1 year 363 days 13 hours, about 35 hours shorter than FF said  but that is good enough for this flight. If I was going on to several other planets it would be good to tighten that up a bit, experience will tell you what sort of flight time error is acceptable for certain paths. In no case should you need better than +/- 6 hours in RSS.

 

 

[CitizenVeen]

Hey Plad!

 Thats one awesome tutorial. Thanks so much!

[leudaimon]

I'm trying to figure out the output for the starting "parking orbit" I should aim for at launch. I see that its inclination is provided, but couldn't find the correct longitude of ascending node anywhere.

I wonder whether the only way to figure it out is by using hyperedit and a dummy spacecraft and maneuver node, as you exemplify in the tutorial? I'm doing a career in RP-0 and would be glad if I could figure out some way of launching correctly without needing a new edit in the savefile for every launch. Even though AN longitudes are not easily available from KER, it is possible to eyeball it from some orbital parameters such as angle to equatorial AN before launch. 

As I imagine the longitude of AN for the boost is already used in the calculations, it could be easy to include in the final output.

[PLAD]

5 hours ago, leudaimon said:

I'm trying to figure out the output for the starting "parking orbit" I should aim for at launch. I see that its inclination is provided, but couldn't find the correct longitude of ascending node anywhere.

I wonder whether the only way to figure it out is by using hyperedit and a dummy spacecraft and maneuver node, as you exemplify in the tutorial? I'm doing a career in RP-0 and would be glad if I could figure out some way of launching correctly without needing a new edit in the savefile for every launch. Even though AN longitudes are not easily available from KER, it is possible to eyeball it from some orbital parameters such as angle to equatorial AN before launch. 

As I imagine the longitude of AN for the boost is already used in the calculations, it could be easy to include in the final output.

I actually don't determine the LAN of the start orbit in the calculations, though it is a reasonable assumption as it could be figured out from what is calculated. However Okder came up with a superb addon for Mechjeb that tells you when to launch, shows the best parking orbit, and sets up the transfer node to the first flyby planet (in KSP as you are running it), all you need  from FF is the start day and flyby day at the first planet. I put a review and runthrough of it in it's thread. It beats being given just the LAN, I recommend it.

[leudaimon]

@PLAD Looks a really nice option. I like to fly manually, but will give it a try in the weekend. Thanks!

[romanasul]

Unfortunately the tool doesn't work with the latest Mechjeb, it made things very simple. Until it's updated we have to do the old guesswork.

[bigguy4u]

how do I use this

Edited May 20, 2016 by bigguy4u

[Bob Jub]

What am I doing wrong? No matter what I do I can't get a 3 planet flyby. I add search dates all the way to 2900 and still didn't come up with anything.

[PLAD]

18 hours ago, bigguy4u said:

how do I use this

Hello, and welcome to the forums! I do not know if you have just started using KSP with RSS installed, my first comment would be that it is good to use stock KSP for a while before moving to RSS as it is much harder than stock. If you have been using RSS for a while then I recommend starting with the two tutorials in the first post of this thread, one that is just for RSS and the one for basic Flyby Finder.

-PLAD

[PLAD]

12 hours ago, Bob Jub said:

What am I doing wrong? No matter what I do I can't get a 3 planet flyby. I add search dates all the way to 2900 and still didn't come up with anything.

E-V-M windows are somewhat rare, however the following changes to the screen you show will find the next one:

Hit "add" three times so the search window start dates are moved forward 300 days, so Earth will be 3106, Venus 3150, and Mars 3200. Then more importantly the search periods for Venus and Mars need to be increased, Venus from 100 days to 400 days and Mars from 200 days to 400 days. Your "V at SOI" is a bit low, try 5000m/s instead of 4400. Then you should find solutions. The previous window I found is to press 'subtract' 4 times so Earth starts at 2406, with the window periods at 400 and 400 days and Vinf at 5000m/s as above. It is often hard to get the first 'hit', try raising the V at SOI way up and enlarge the search periods way out ( I start at 1000 days) until you find something and can narrow the parameters.

[Zuppermati]

Avira tells me it has a filerexsnxclass [pup] virus