SAS for probes?

[MrPopcup]

hello there everyone, sense 0.18 came out I was waiting the whole time for SQUAD or anyother modder to release an SAS or ASAS thing for probes, like a small one and lighter in mass, so we can actually make probes not that heavy ( compared to probes with ASAS and with the fuel.. ) , at least this is my question,

- Has any modder made an ASAS for probes?

[astropapi1]

There's no ASAS now. If you're asking for reaction wheels, I think they will add the KSPX one.

[MrPopcup]

There's no ASAS now. If you're asking for reaction wheels, I think they will add the KSPX one.

Thanks for telling me, its 3:00 AM right now I really need to sleep x), tomorrow work uh ;O.

but anyway, I'll wait untill tomorrow's morning and see what others think/have.

[astropapi1]

Thanks for telling me, its 3:00 AM right now I really need to sleep x), tomorrow work uh ;O.

but anyway, I'll wait untill tomorrow's morning and see what others think/have.

Good night.

[Sof]

The probes can be controlled in 0.21.1 without an ASAS piece on them.

Other than that, there is a small ASAS stock part. If you can't make do with either of them, then your probe isn't as light as you want it to be in the first place.

[dlmarti]

hello there everyone, sense 0.18 came out I was waiting the whole time for SQUAD or anyother modder to release an SAS or ASAS thing for probes, like a small one and lighter in mass, so we can actually make probes not that heavy ( compared to probes with ASAS and with the fuel.. ) , at least this is my question,

- Has any modder made an ASAS for probes?

probes are so light, that the reaction wheel built into the control node is enough.

[SRV Ron]

I place a SAS in the probe stage of my rocket as it provides a convenient place to mount a thruster pack as well as its ability to control the rocket throughout its flight. It allows me to reorient the rocket without thrusters for maneuver burns. I will turn it off once I stage to the probe as it will be too much control for the probe stage. The one exception was after I landed the probe in the ocean of Laythe. I turned it back on to keep the probe upright in its ocean.

[magnemoe]

probes are so light, that the reaction wheel built into the control node is enough.

However if you have an two ton probe you might want an reaction wheel but don't want the 0.3 ton sas module, one option might be to use an larger probe or perhaps multiple.

Remember that the torque uses power so you want an battery

[SRV Ron]

However if you have an two ton probe you might want an reaction wheel but don't want the 0.3 ton sas module, one option might be to use an larger probe or perhaps multiple.

Remember that the torque uses power so you want an battery

An option is to place the SAS under the decoupler for the probe stage. That way, it is available for orientating your rocket for maneuvers without using thruster, but can be ditched as useless weight when the probe SAS alone can handle the job. A small battery pack and fixed solar panels or a nuclear battery will solve the power issue.

[Geschosskopf]

@ Mr. Popcup:

It really depends on the probe core you use. The smallest 2 or 3 of them no longer have any built-in torque (which comes from reaction wheels). Thus they alone cannot turn your ship and you need to add some other parts that can, which kinda defeats the purpose of using the dinky probe cores.

Just to be sure we're on the same page with the terminology.....

All probed cores and cockpits, regardless of size, have the SAS function built in. SAS is now just stabilization attempting to use whatever means of control are on the vehicle to keep it pointed in the desired direction. Also, when you give control input on 1 axis, SAS holds the other 2 axes still (in theory). So, SAS requires some sort of control (RCS, canards, reaction wheels, etc.) or it does nothing. And the avionics package for planes just does SAS, too, so it's now redundant because every core and cockpit already does that. You can turn SAS on and off with the T key.

Now for the confusing part: reaction wheels. These things provide torque to turn the vehicle but consume electricity while doing so. All stock cockpits and the large and medium probe cores have some weak reaction wheels built-in, but not the smaller probe cores. What makes this confusing is that the old parts for SAS and ASAS modules, which still look the same and are still labeled as SAS and ASAS modules, are actually now strong reaction wheels. So, adding the "SAS" and "ASAS" parts is adding pod torque, simple as that (and also adding power consumption).

The reason for having torque is so you can turn the vehicle without needing control surfaces, RCS, or whatever. The amount of torque needed depends on the size of the vehicle and also its proportions. For example, short, essentially cubical/cylindrical probes have low moments of inertia about all axes so can get by with a little torgue, probably just a large/medium probe core. But a long, skinny probe of the same mass with the same torque will roll very well but be slow in pitch and yaw. And of course, the bigger/heavier the probe, the more torque you need, so maybe add a set of reaction wheels (as in the old SAS/ASAS parts).

Note, too, that when SAS is turned on, torque seems to be its 1st choice if there are multiple means of control. So, if you have any reaction wheels (built into the cockpit/probe core or extra), and you run SAS, you'll probably be using a little electricity constantly. Thus, every vehicle which reaction wheels (which is everything but the smallest probes) now needs RTGs or solar panels just to stay alive very long. And the more torque you have, the more electricity you need.

[arq]

@ Mr. Popcup:

It really depends on the probe core you use. The smallest 2 or 3 of them no longer have any built-in torque (which comes from reaction wheels). Thus they alone cannot turn your ship and you need to add some other parts that can, which kinda defeats the purpose of using the dinky probe cores.

Actually, in 0.21.1 (released very shortly after 0.21), they added torque to every probe core, so now every ship (non-debris object) has reaction wheels. For most probes, the probe core torque is usually sufficient. If it is so much heavier that the torque is insufficient, the mass of a reaction wheel is usually not too detrimental.

[MrPopcup]

thanks everyone! i've got my answer!

@ arq, I have updated to 0.21.1 just yesterday, wasn't available that much.

@ Geschosskopf, thanks for the great answer! explained everything I wanted and even more!

note: I asked because I didn't know that SAS was built in command modules, but now I know!