Remote Tech 2: Question on landing on bodies without atmosphere: kOS, SCANsat,...?

[soulsource]

Hi!

I've started a modded career mode save with 0.24.2 using (as one of many mods) Remote Tech 2. Up to now landing isn't an issue, since my comm network does not reach out of the Kerbin system yet, so that the signal delay is low enough to allow nearly realtime control of probes. Nevertheless, I'm planning to go to other planets soon, and I'm wondering if, and if yes, how landing on bodies without atmosphere is possible. I mean, of course one could program a course on the flight computer that will have the craft have a defined velocity at a certain altitude, but, well, how should I know the elevation of the ground below the ship to choose the altitude at which it should be slowed down?

So, I'm planning to add another mod to my game - one that will help me with that issue, and I'd like to ask for your help on deciding.

Mechjeb, or any other "does everything for you" solution is a no-go for me. If I can write a program that takes care of the landing, that's fun. If the program is already written and I only have to press the "Play" button, it's boring.

I've been thinking about two possibilities:

• If I'm not mistaken, kOS or kRPC have variables that give you the radar altitude, so it should be doable to write a kOS or kRPC script that brings down the probes speed at the right point during descent. Nevertheless I have no idea, if this works for probes without crew pod, because with the games GUI one only has a radar altimeter in IVA... Also, from what I've read the integration between kOS and Remote Tech is not finished yet, so kOS doesn't care about antenna range. Does kOS respect signal delay in some way? How about kRPC?
  
• The second option I thought about is to make a map of the body the probe should land on using SCANsat, and to use that map as an estimate for elevation, before programming the flight computer appropriately. This is of course less exact, since the flight computer does only allow commands, no conditional programming, and the burns have to be calculated well. Added difficulty: The probes mass will change with spent fuel...
  

Which of these solutions would you use or are you using? Are there any other addons that work well? Is there another way to make a controlled landing on a body without atmosphere with signal delay?

Thanks in advance!

[Mecripp]

I found it best to make a command ship with 6 kerbals and send it to like Duna first then probes.

[soulsource]

That of course circumvents the signal delay issue, but if I already have Kerbals in orbit, I could as well send a manned lander, and I'm somehow fixed on the idea to send a probe. ;-)

[Nori]

I'm curious about this too.

My idea was to send a command ship, but that is further down my tech line than I am right now, so that isn't a option yet.

Just getting into kOS and it is stellar, but do wonder about the remotetech integration. Guess I need to test it out more and see.

[soulsource]

After some thought I also installed kOS and started playing with it a bit. I guess, since it can be set to run a program when an action group is activated, it should be possible to have signal delay taken into account properly when it comes to program execution. Antenna range is another issue. At the moment the connection to the Archive at KSP is instantaneous and does not have a range limitation, so updating scripts in flight is possible anytime, anywhere, and (probably) without any delay. I guess, one just needs to stick to the RT2 rules and only use this when the craft has contact to KSC...

[Zylark]

If you ever do figure it out, do let me know. I got a probe going to Duna, with a lander attached that is supposed to land on Ike. Which might not work all that well considering there will be a significant time delay making small adjustments pretty difficult.

I am also using Mechjeb - but I guess that "sends" commands from KSC rather than local on the lander should I use the "Landing Guidance" function of MJ.

[themongoose]

You could try this:

http://forum.kerbalspaceprogram.com/threads/50736-0-23-5-%28Apr-02-14%29-Automated-Vertical-Velocity-and-Altitude-Control

I have been experimenting with it myself but have been having a few problems. It does seem to consume more fuel than if I controlled it myself, and also does not seem to control the horizontal movement at all, so you need as straight-vertical drop as you can (again using more fuel).

[Sakata]

After some thought I also installed kOS and started playing with it a bit. I guess, since it can be set to run a program when an action group is activated, it should be possible to have signal delay taken into account properly when it comes to program execution. Antenna range is another issue. At the moment the connection to the Archive at KSP is instantaneous and does not have a range limitation, so updating scripts in flight is possible anytime, anywhere, and (probably) without any delay. I guess, one just needs to stick to the RT2 rules and only use this when the craft has contact to KSC...

One thing I could comment on here. We regularly send programming to satellites already. kOS would just be a program sent to the probe, then the probe can run the program locally. So there is no delay, aside from the delay of sending the probe the programming ahead of time.. That is one of the things that I thought was goofy with remotetech assumptions. Manual commands being sent would take a while, but if you send a program ahead of time, then the probe can run the program whether it has a signal or not.

[Whovian]

I know someone on Youtube did a mission to Duna and Ike completely via kOS, so it's definitely possible with kOS. Mechjeb can also do landings, but I'm not sure if the commands Mechjeb sends to the ship are affected by Remotetech delay. I don't think there's any other way, though, unless you're really good at timing and landing blind.

[soulsource]

I've restarted my career with 0.25, so it'll take a while until I got the communications network set up again (I haven't even unlocked antennas that can reach other planets yet). But once my communication network is in place, I'm going to use kOS. I've meanwhile written a script for it that manages to land on the Mün without issues, as long as the TWR is high enough that the crafts mass does not change significantly while hovering (and fixing that would be a minor correction). It's not very efficient, but still much better than any manual landing I've performed up to now...

So, my plan is to already copy that script to the kOS storage within the vessel before launch, and to make kOS wait for an action group toggle to run it.

I don't know the syntax by heart, but it's something like

WAIT UNTIL AG1=TRUE. RUN land.

So, when I press the "1" key, RT2 will delay the activation of AG1 with the proper signal run time, and after that has passed, the activation of AG1 will cause the kOS WAIT command to finish, so that the next kOS command, which will run the land script, will be called. That in my opinion doesn't really break immersion, since the land script is being run locally on the probe, and starting it still has to be done some time ahead.

[notsorightstuph]

I too have been looking into this. I was givong this link in a Google plus Kerbal community.

http://ksp-kos.github.io/KOS_DOC/structure/config/index.html

It seems that integration of these two modes is still in the experimental stages.

I don't see having kOS run a landing or circulation burn script as breaking immersion in a realistic type of game.

Its what NASA would and has done with mats missions. Its more realistic tgsn sending a six Kerbal crew.

[carlorizzante]

Assuming RemoteTech is installed, there is any other way to land a probe on a distant body other than kOS, or a Command ship?

Both solutions seem overkill, one is a bit too technical for the casual player, the other is a bit of a nonsense. It would be awesome if RemoteTech would have some sort of rudimentary landing assist, just like it has already a basic flight assistant.

Edit: Ok, what about a suicide burn programmed with a maneuver node? Warzouz proposed it for other reasons, but it might very well work for landing a probe with RemoteTech as well.

"...you could also do a direct landing. Set your PE near the surface, set a node at PE, pull it until it flips. the start landing at the count down = burn time. It's a hyperbolic suicide burn . I did it once or twice. Fun but beware of cliffs!"

 

Edited July 12, 2016 by carlorizzante