[13:57:26] NASSP Logging has been started by n7275 [13:57:30] Guenter! [15:46:06] hello [15:46:37] good afternoon [15:46:58] haha I wouldn't even be surprised [15:48:12] Graham2001 from the forum just sent me a DM, we got the Skylab deorbiting study document thanks to him saving it from NTRS. I will create an EMP file for the DAP changes for Skylark. [15:48:28] he asked if we had tried that yet with Skylark [15:48:34] nope, but I will now! [15:48:38] oh that's great! [15:48:43] totally forgot about it [15:48:56] will be an extra video [15:49:09] actually something that will be visually interesting :D [15:51:17] I thought it was interesting :) I might be biased though... [15:53:48] yeah I think it was fine, just a lot of DSKY pushing :D [15:57:28] they would have deorbited Skylab with two SPS burns [15:57:33] first a shaping burn, I think [15:57:52] similar to how they did the CSM only deorbits on the Skylab missions as well [15:58:08] I haven't really figured out how they would have targeted those... [15:58:44] aim for the middle of Austraila [15:59:16] sure, I can target the shaping burn for Australia. And then the Earth rotates it away and is somewhere else by the time of deorbiting :D [16:00:17] I have a small telemetry client request [16:00:30] while I'm thinking of it [16:00:33] don't say V74, that's not small :D [16:00:53] but sure [16:00:55] haha, no [16:01:05] Resolver output voltage [16:01:52] ah yeah [16:01:59] we have GUI boxes for it in the CSM client, but no decoding/display [16:02:26] will be added [16:02:29] according to the CSM-113 telemetry curves it should be -21 to +21 Volts [16:07:52] thanks :) [16:10:12] it's sine and cosine separately in the GUI boxes [16:10:22] good enough or should I let it calculate the angle? [16:11:54] I guess I can start with the voltages [16:12:12] surely we can do some atan2 in our head [16:15:57] morning! [16:16:25] I don't think you can -- based on the descriptions I've read, I think it might saturate -- since the signal itself is 28Vrms [16:16:52] so you need to look at which one of the two is actually usable, and then acos or asin only that one [16:17:20] ah yeah, I remember reading something like that [16:18:04] I've got a RTCC telemetry routine [16:18:09] TLRESL [16:18:14] "TLRESL computes gimbal angle attitudes from the LM resolver outputs." [16:26:37] it was a good thing that I was pushed to make the erasable memory update displays in the RTCC MFD as comfortable as it is [16:26:48] because setting up these uplinks just now was quite simple [16:27:11] already in P40 [16:29:25] this is just a test. I promised to make a video about this, but for that I will schedule the burn in daylight... [16:40:53] spun out of control [16:41:05] I'll have to check my uplinks and other DAP settings [16:45:21] it looked like the initial gimbal trims weren't good [16:45:45] strange, I thought I could use the ones from the deorbit document [16:51:11] don't think I did anything wrong. Maybe it's just the trim gimbal angles not matching [16:51:22] deorbit document vs. NASSP behavior [17:16:54] just voltage [17:18:51] I'm just multiplying those values directly by a fixed value, since the voltage we power the IMU with is raw bus voltage [17:19:59] ...for now [18:05:11] oh that's interesting that it doesn't work out of the box [18:14:34] I think I should be able to sort out ebank 7 tonight. it's actually a lot less scary now that I've divided up my erasables list into groups, and separated out all of the ones that appear in artemis from what's new in Skylark [18:14:57] makes it very easy to see which groups from Artemis are still contiguous but have just shifted around a bit, and where Skylark stuff can be slotted in [18:20:29] yeah most of the Artemis ones shouldn't have changed much [18:20:38] maybe some lunar only stuff removal, but probably not a lot [18:21:12] not a lot, but enough that my build is currently failing with a few dozen errors after deleting them last night :D [18:25:45] ah damn, for a fully custom RTCC CG calculation I still need to make the docking roll angle customizable [18:25:54] but I am trying the burn again with better SPS trims [18:27:13] and we need to be able to dock *with* a roll angle, at some point too [18:30:06] right. At least a bunch of places in the RTCC can handle that already [18:30:30] second burn, trims were still way off. But after a while it compensated, didn't spin out of control [18:30:41] residuals weren't even bad, but it did a 40° attitude excursion in between [18:31:02] it seems like it wants an almost maxed out (positive) pitch trim [18:31:22] which seems weird. And way off from the deorbit study document [18:31:33] that was one of the first things I wondered when I saw the CG location [18:32:41] did the CG vary much over Skylab's life? I can't imagine it did. [18:32:53] SCS Auto TVC is fairly happy [18:33:15] +3.5° in pitch and -2.5° in yaw is what the trim angles are [18:36:20] I wonder if we got anything wrong with the Skylab CG [18:36:43] that's always possible [18:37:34] the document has a +27 inches ZCG [18:37:38] in CSM coordinates I believe... [18:41:03] can't say our CG agrees with that. But for now this deorbit study document is the one that is supect for me :D [18:41:24] in the docked attitude the CSM +Z is pointing mostly away from the ATM [18:42:00] and I believe the ATM is what makes the Skylab CG (including ours) off the centerline [18:45:14] oooh [18:45:20] they have the CSM docked differently [18:45:34] that would do it :D [18:45:54] "Although the CSM clocking angle was changed to 245 degrees before [18:45:57] simulation, it was not possible to update the data in time to support the [18:46:02] simulation schedule, which was constrained by the necessity of establishing [18:46:04] the SPS gimbal control limits for flight actuator modification milestones." [18:46:12] "Because the forcing function for the bending is the magnitude of the SPS [18:46:16] gimbal excursion from the vehicle centerline, the 180-degree clocked CSM [18:46:23] should have the same gimbal excursion as the 245-degree clocked CSM." [18:46:24] "The pitch and yaw gimbal excursions for the 245 clocking are not parallel [18:46:25] to the CSM Y- and Z-axes; however, the pitch excursion is predominantly [18:46:26] along the Y-axis, and yaw is predominantly along the Z-axis." [18:48:03] so I think in this study the CSM is 145° rotated from where our CSM is [18:50:16] uhh [18:50:20] "The SPS engine installation biases were also changed from 2. 15 degrees [18:50:25] to -3.69 degrees in pitch and from +0.95 degree to -2.72 degrees in yaw to [18:50:29] be compatible with the CSM 1.5- and CSM 2.0-degree gimbal control [18:50:33] authority." [18:50:34] what? [18:51:20] that's not what the real spacecraft or the software has :D [18:51:37] ?? [18:53:16] oh I guess, with the correct docking angle, that's what you have to do if you want to keep the gimbals near 0° trim [18:53:30] because as I said, my pitch trim was nearly 4° [18:53:36] close to the limit [18:54:34] I'll do one more burn with an even better trim, but then I will use a different TIG to make a video about it [18:54:41] in daylight [18:59:07] the changed DAP makes the SPS gimbal movement very conservative [18:59:32] important reason why the trims need to be close to correct at ignition [21:15:00] night!