02:03 <Bornholio> look at this sexy beast https://github.com/KSP-RO/RealSolarSystem/releases/tag/v14.0.0

07:14 <Mike`> Bornholio, what's your opinion on SRB pricing compared to liquid stages? :)

11:31 <Bornholio> its alright, they cost a lot less to launch generally after you factor in roll out Mike`

15:01 <Mike`> Bornholio, well, that's what i hoped, but it's not the case unless my rollout foruma is somehow broken. But i reset it today just to make sure so it should be okay.

15:01 <Mike`> I probably should file an issue about it with screenshots and maybe craft files.

15:06 <Mike`> I built a Titan 1 like rocket. One time in a "heavy" configuration with triple first stage and ~17k dv, weighting 274 tons, one with just a single first stage plus 6 castor 1SRBs with ~15k dv weighting 154 tons

15:07 <Mike`> the smaller one using the castors has indeed lower rollout costs - 24.7k. The triple core variant has 25.9k.

15:09 <Mike`> but considering the performance difference, this looks like peanuts. I probably should make a better comparison though, maybe once i have unlocked larger SRBs.

16:09 <soundnfury> Mike`: my experience has been similar; solids are generally only worthwhile when you need to slightly 'stretch' an existing design rather than going to something much bigger

16:35 <Mike`> soundnfury, yes. While i have no clue how realistic that is, i can imagine that the general direction is okay, but i think the extent to how much cheaper liquid fuel is at least looks weird. but i think i'm going to prepare an issue with a somewhat okay comparison.

16:55 <soundnfury> Mike`: well, one thing I've noticed as regards costs is that there's basically no point to stuff like the HG-3 except in the specific case where you're trying to get towards a shuttle-type design

16:57 <soundnfury> kerolox core stages are just so much cheaper than the hydrolox-with-solid-boosters approach, and yet IRL the latter seems to have been favoured (Delta etc., too, not just STS)

16:57 <soundnfury> though that may just be because the H-1, specifically, is quite amazingly cheap

16:58 <Mike`> the LR87 is about as cheap if not cheaper

16:59 <Mike`> no idea how expensive hydrogen really is to use, but considering they still use the delta iv today, it seems to be somewhat okay

16:59 <Mike`> even more so for high energy upper stages

17:01 <soundnfury> OTOH, DIV is super-expensive (iirc DIVH is about $400M). OTGH that might just be me comparing it to F9/FH prices

17:01 <soundnfury> now for upper stages, yes hydrogen makes a lot of sense, both in RP-1 and IRL

17:03 <Mike`> :) i would like to know the reasoning behind the delta iv/rs68

17:03 <awang_> OTGH?

17:04 <soundnfury> Atlas, Delta, Ariane, H-II and GSLV all have hydrolox uppers at least as an option

17:04 <soundnfury> awang_: On The Gripping Hand

17:05 <Mike`> yeah. i've not progressed to lh2 engines yet in my career, but if they're priced so that they're useful as upper stages, that's good to hear. :)

17:05 <soundnfury> Mike`: probably just the result of the 'Isp über alles' mentality

17:05 <soundnfury> (rs68 that is)

17:08 <soundnfury> for upper stages, the RL-10 is rather awesome

17:08 <soundnfury> (though it doesn't displace the AJ10 and Agena from _all_ uses)

17:09 <Mike`> in my early career i rather dislike those as the rd0105 is just so much better. :)

17:09 <soundnfury> ah, see I haven't really touched Russian engines yet

17:09 <soundnfury> apart from occasionally playing around with the early staged combustion ones

17:10 <soundnfury> one of these days I'll do a russkie career

17:10 <Mike`> yeah, the s1.5400 is awesome, too

17:11 <Mike`> the rd0105 is a node or two higher in the tree than the aj10, but runtime and Isp are worlds better. thrust is higher aswell.

17:38 <soundnfury> thanks for that

17:42 <Mike`> the 0105 does have a disadvantage in very limited vector control (depending on the model, the stock model has plenty vectoring, but the RealEngines i'm using doesn't - this is because the real engine just used verniers, i guess - so i tend to avoid to use the engine too low in the atmosphere

17:43 <Mike`> For anybody interested in my SRB comparison: https://github.com/KSP-RO/RP-0/issues/893

17:43 <Qboid> [#893] title: SRBs too expensive compared to liquid boosters | So, i was a bit shocked at SRB prices (in RP-1/Developmental), and thus did a little comparison. Test vehcile was a Titan 1 like rocket with 7.7t lead ballast. For the SRB test, i attached two 100 inch SRMs with decouplers. For the liquid booster test, i attached 4 more titan 1 first stages, again with decouplers. To get similar pe

17:43 <Qboid> rformance, i reduced the fuel level of the liquid boosters. Both rockets used identical staging, the center engine is only lit after the boosters decoupled.... | https://github.com/KSP-RO/RP-0/issues/893

17:47 <awang_> soundnfury: ...Gripping hand?

17:49 <soundnfury> awang_: http://catb.org/jargon/html/O/on-the-gripping-hand.html https://en.wikipedia.org/wiki/The_Gripping_Hand

17:49 <Mike`> Bornholio, in this comparison, even rollout costs alone are higher for the SRB version, and when you factor in part costs and the also higher build time, the SRB version looks useless. :(

17:53 <awang_> "frequently observed among hackers"

17:53 <awang_> Apparently I don't hang around enough hackers

17:53 <soundnfury> well you hang around me

17:53 <Mike`> :D

17:54 <soundnfury> and now you've observed it

17:54 <awang_> Although it took a few years

17:54 <awang_> That's a very generous definition for "frequently" though

17:55 <soundnfury> only 'cos I haven't had opportunities to use it before

17:55 <soundnfury> :P

17:57 <awang_> Mike`: Yeah, Russian engines are kinda insane for early RP-1

17:57 <awang_> Also, nice issue

17:57 <awang_> Interesting that SRBs end up so much more expensive

17:57 <awang_> soundnfury: True, true

17:57 <awang_> Also, "DIV is super-expensive (iirc DIVH is about $400M)"

17:58 <awang_> I was really confused coming from #kspacademia talking about performance-related things

17:58 <soundnfury> awang_: Russians being OP in the early years of the Space Race is just historical accuracy though ;)

17:58 <soundnfury> lol

17:58 <awang_> I was like "yes, the DIV instruction is expensive, but where did $400M come from"?

17:58 <awang_> soundnfury: Very true

17:58 <Mike`> haha :)

18:00 <soundnfury> clearly $400M is a literal representing 400 Mexadecimal (i.e. four times mteen²)

18:01 <soundnfury> (perhaps, after the Greeks, we should take M (µ) as _myriori_, 10,000, then 4µ² is indeed 400e6 ;)

18:04 <awang_> mteen?

18:04 <awang_> Too much jargon :(

18:04 <soundnfury> as hexadecimal is sixteen :P

18:05 <soundnfury> I was trying to make up a bogus number system

21:08 <Mike`> which year's dollar price do we use when costing parts? i've read that somewhere in the past but can't find it again. :|

21:33 <Mike`> https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720007149.pdf might be an estimation for UA1205 costs at 2.414 million 1971 dollars recurring costs

21:41 <awang_> Mike`: IIRC it's 1960

21:42 <Mike`> awang_, just found a quote by pa'p in the forum thread stating 1965

21:42 <Mike`> should've looked there earlier, i guess. on the other hand, it would probably be useful to document that somewhere in the wiki

21:42 <awang_> Mike`: Yep, just found teh same

21:42 <Mike`> :D

21:42 <awang_> But in my irc logs

21:42 <Mike`> oh okay

21:42 <Mike`> thanks for checking

21:43 <awang_> It's not documented?

21:43 <awang_> Sort of surprised

21:43 <Mike`> well, it might be and i'm just too blind to find it now

21:43 <Mike`> i remember it reading somewhere, but no idea where that was

21:53 <awang_> Well the "sort of" is because far too many things are undocumented anyways :P

22:32 <Bornholio> Mike`: i have a feeling a lot of work needs to go into rollout costs, given a reasonable gemini cost more than STS launches did IRL. Also if you have to rollback its not worth it just scrap the thing

22:32 <Mike`> yeah - rollback is another problem, rollout should really just be rollout and KCT should support "integration" costs separately

22:33 <Mike`> scrapping has the problem of taking the time to build another rocket

22:35 <Bornholio> BP = earn rate so i keep that high, one wasted rollback costs a lot more BP than a build

23:00 <Mike`> rollbacks cost BP? I'm a little confused. :) In any case, the srb/liquid pricing is hopefully somewhat easily fixable. I only managed to find one price estimation for an srb though.

23:01 <Mike`> about the rollback-problem, i wonder what the local RIS rules are on a failed ignition on the pad, reload a save? :)