Is it expected behavior that Command Discs always use a minimum of 60W when Heading Lock is active?
Is it intended that you can "cheat" your way out of that by powering off your primary Command Disc (the one under player control) and relying on a second one for gyro control?
Is there a reason additional Command Discs don't inherit the "Heading Lock" setting, even if Replicate Commands is on?
Could that be cause of occasional rapid "wobble" I see on craft in space - i.e. two gyros "fighting" each other for heading control?
Here's some background...
I enjoy designing ultra-light spacecraft to see just how much excess mass I can trim. Right now I'm making a lander for Niobe with a final stage less than 10 kg.
Part of the exercise is avoiding too much excess battery capacity. I usually gain a rough calculation of what I need by looking at the Power Consumption of parts in the designer, and multiplying by the amount of time the craft will be powered by the battery in question. It's not a perfect equation but gets me close enough to fine-tune the rest of the way by trial and error.
However, I noticed some substantial discrepancies when working with small Command Disc parts. The Power Consumption shown in the designer seems to be based solely on the component's Gyro volume. e.g. It reports 1W consumption, but in flight the disc actually consumes 6W nominal and 60W if "Heading Lock" is activated (plus whatever power the gyro pulls). After wondering why my battery was draining in a minute instead of an hour, I've learned to account for that.
I also noticed the initial Command Disc that is automatically added to a craft doesn't show fuel bars for it's battery capacity, or the gyroscope "tab" on its in-flight inspector. All subsequent discs show this. The information is very helpful and I'd love to get that bug fixed. While you're at it, exposing the Priority property for the Command Disc in the designer would be incredibly helpful - it's crucial for making sure the right battery is drained first on craft that have more than one Command Pod. I've already filed a bug report for these issues, here:
https://www.simplerockets.com/Feedback/View/6o1seg/Initial-Command-Disc-is-missing-inspectors
https://www.simplerockets.com/Feedback/View/yt73Af/Command-Disc-missing-fuel-priority
Thanks!
(Note: This is a response to Toinkove's post, which seems to have disappeared?)
Thanks Toinkove.
The final lander stage is pretty simple and looks like this: https://i.imgur.com/EyisB4p.png
Here's the full craft in its current incarnation:
https://www.dropbox.com/scl/fi/fome0ea40m5efjnri64rv/Niobe-NanoLanderC.xml?rlkey=feyuyzfjy2qud7p0adzrwnxxc&dl=1
It's still a work in progress. I'm adjusting for larger battery capacity (at the moment it's basically a command disc in each stage with their priority set manually in the XML), and I acquiesced to adding a solar array for the interplanetary stage (I was going to just use batteries and power down the command disc while coasting, but it was becoming a bit of a pain to make sure I remembered to turn it on each time just before a scheduled burn).
Everything is symmetrically balanced.
For kicks I want to see if I can land using a lightweight RCS thruster as my main engine (tied to the Throttle input). The designer doesn't compute Staging Analysis for thrusters, but I did some manual calcs and figure that final stage on the lander should have around 800m/s dV. The approach seems plausible in theory:
https://imgur.com/a/pzaAC3i
Though that was just a test landing with a "cheater" interplanetary stage and I need to fix it up. For some reason transfer is taking me a fair bit more delta-v than the map I looked at.
The thruster on top is to help me stay grounded briefly upon landing.
Any comments very welcome!