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Posts posted by TimothyC

  1. 15 hours ago, Pappystein said:

    3) we finally know Pratt and Whitney's designation for their un-built (well at-least un-flown) LR-119 meant for the S-IV and S-V stages.    RL10B-3 (YES that is correct!)   It appears that back in the 1960s P&W used the letter after the engine name to denote cycle.   So the LR-119/RL10B-3 is a LR-115/RL-10A-3 with a different or at-least altered combustion cycle.   We have already seen this in the amzing RL20 that Zorg has integrated into BDB.


    If you read the text, it's the same combustion cycle, the nomenclature was simply not established at the time.

  2. 2 hours ago, DeadJohn said:

    1) By itself (and its mod dependencies), BDB already provides LH2 engines and LH2 switchable tanks that have boiloff. Boiloff can only be turned off in the BDB settings menu, not through parts upgrades nor electricity consumption. Is that correct default BDB behavior?

    This is correct behavior. The BDB dll has basic cryogenic functionality integrated independent of Nertea's work.


  3. 13 hours ago, OrbitalManeuvers said:

    Hopefully this is an OK place to ask these Skylab questions:

    1. After skylab is placed in orbit, the S-II is meant to separate, correct? Is it meant to somehow de-orbit as well?
    2. Is skylab meant to fine tune its orbit? I'm guessing that if so, it should be done before the ATM is repositioned, via RCS?
    3. I need help with RCS placement on the lab. The friznit wiki says "2 ACT RCS Unit top and bottom at the rear of the lab" but I don't get what is top or bottom or front or rear. There are no RCS thrusters that I can see in the images. Any hints on their intended location would be super helpful. Also, I'm guessing they're not intended to help with orbit adjustment (if that's meant to be a thing at all) because they don't have any forw/bkwd jets.

    Also, if there are no hard and fast rules about this stuff that's cool, I'll just make up stuff ... just thought I'd ask!

    P.S. This whole release is amazing!

    I would note that while launched in May of 1973, S-II-513 (the second stage of the rocket that launched the station) was on orbit until 11 January 1975. This does mean that the S-II stage was in orbit for nearly 11 months after the last crew came home. Because the S-II was lighter (probably around 40 tons following the stage being inerted) than Skylab, and had a more consistent cross section for drag to act on. Skylab was maintained in a solar-inertial (so that the solar arrays always pointed toward the sun) mode while in operation, left to switch into a gravity gradient (one end of the station always pointing toward the earth, meaning the solar panels would act as a drag break in the upper atmosphere) mode after the last crew, flown in an end-on velocity vector (IE, to present the smallest possible cross section for drag, the station was turned so that the long axis would remain parallel to the orbit at the cost of using the gyros and limited rcs prop*) when they thought they might be able to reuse the station with the shuttle, and finally back to the gravity gradient mode to accelerate and control de-orbiting when it was obvious that the Shuttle would not be able to get up in time to reboost the station.

    *Skylab RCS prop was GN an was designed to allow the possibility of on-orbit refill, even though the station was designed with a rather short orbital life.

  4. 10 hours ago, Dr. Jet said:

    For nuclear engines? Like RD-0410 and Nerva? Then you should know that RD-0410 was gas-fed and Nerva has exploded (test of 1959) because of liquid hydrogen evaporating too fast. Neither of those was ever concidered to be CO2 fed. I'm not sure if it's even practical.

    Non-hydrogen propellants for nuclear thermal engines were considered in the 1960s as a way of retaining long-term storability on deep space missions (mostly things like Ammonia). The idea died out as the NTR programs did. However, CO₂ as a propellant for nuclear thermal engines came back under consideration starting in the early 1990s with Zubrin's work Nuclear thermal rockets using indigenous extraterrestrial propellants. This work mostly focused on Mars and Titan, but included data for all kinds of liquid fuels in NTRs. The paper does also note that a nuclear engine using a propellant that is an oxidizer at high temperatures (water, carbon dioxide, ect) would have different fuel cladding needs that one that used a hydrogen based propellant (hydrogen, methane, ammonia), limiting single-engine utility for mars applications.

  5. On 10/2/2019 at 1:00 AM, Dr. Jet said:

    1) CO2 is not something you want to store as liquid. EVER. It will need constant heating (30°) and too high pressure (heavy tanks). On the other hand SOLID form of CO2 ("dry ice") is easily storeable, does not need any pressure holding at all and converts directly to gas when heated a little bit.

    Hello Dr. Jet. I was one of the people who brought forward to Jade data on NIMF (Nuclear rocket using Indigenous Martian Fuels). While you may be broadly correct that there are limited reasons for using Liquid CO₂ on Earth/Kerbin, the resource here is used as both a stepping stone in chemical processes, and as a fuel for nuclear engines. When using it for nuclear engines, you are going to want it as a liquid anyway, so it makes sense to simply compress it down and and store it as such, rather than freeze it, and then compress the gas that comes off when you need fuel. Furthermore, your temperatures are slightly off. Liquid CO₂ can exist between 217K and 304K while under pressure, which is not the same as maintaining it at 303K as you imply. I'd also note that as far as density goes, Liquid CO₂ is only about 30% less dense than dry ice, which makes it still workable for a lot of rocket applications (in game, the only other application is the production of methalox meaning that the difficulties in storing it are minimal relative to the added complexity of storing it as dry ice and then liquefying it on demand.

  6. 8 hours ago, GoldForest said:

    Made a Delta IV with the DCSS... yes, I made it out of Atlas parts and Titan engines...

    @CobaltWolf @blowfish Any plans to make the upscaled version of the DCSS? The current DCSS is obviously the 4m variant at 2.5, so that would mean... the 5m KSP variant would be... 3.125? Or 3.75?
    And... Delta Heavy...

    Five meter-ish stages (ACES, Delta IV, Atlas Phase II, 5m DCSS, Vulcan, Ariane V core, ect) end up being ~3.125.

  7. 9 hours ago, Pappystein said:

    The name Delta IV was to hide the rocket's true lineage because, as Cobalt has pointed out previously I believe, if you want to be true to lineage the Delta IV should be TITAN V!

    Nope, that's Atlas. Atlas went from III to V because of the functional merging of the Atlas and Titan lines.


  8. 13 hours ago, draqsko said:

    Like I said, I killed a lot of trees working that thing out. First I tried to put a patch to make the Vectors cryogenic but that didn't really work because Ox and LF are fairly close in density and LH2 and LOx are fairly close in density as well, but LH2 and Ox are not even within the same ballpark.

    I'm a bit confused here. BDB, reDIRECT, and CryoEngines/Tanks use Ox in place of LOx. Also, in the real world, non densified LOx has a specific gravity of about 1.1 (water being about 1). Liquid Hydrogen on the other hand has a specific density of 0.07. Now, you need about 5-6 times the mass of LOx that you do of LH2, but that means the LH2 tanks are still a major driving factor in the density of the entire tank system. In average rockets the specific gravity of the total prop (fuel and oxidizer) is about 0.99 for Kerolox, 0.8 for Methalox (Less dense fuel, but more Oxygen), and 0.35 for Hydrolox.

  9. 22 hours ago, draqsko said:

    Meh, would have been better to downsize the SII and SIVB stages rather than downsize the SIC. Or reduce the % utilization while keeping the dry mass the same and increasing the Isp and thrust of the hydrolox stages. I mean 89% of the mass of a tank is LFO, so that 11% kept at true scaled value wouldn't change much if you balance the rest.

    The S-II and S-IC stages have the same diameter, and Cobalt desired to retain the same relative lengths between them, which precludes downsizing them. Cobalt also didn't want to mess with relative volumes (you know how the various size 1 tanks don't have a 1:1 capacity vs length relationship with each other? Cobalt/JSO wanted to avoid that). BDB (really, JSO did a lot of the balancing work) is based on using a combination of real world ISPs and thrusts based on either 25% of real world values (lifter/sea level engines), 50% of real world values (vac engines so that the upper stage burns don't last forever), or 37.5% of real world values (the J-2, because it comes in both sea level and vac versions, and it didn't make any sense for the vac version to have a higher surface thrust than the sea level one).

  10. 11 hours ago, draqsko said:

    BDB's Sarnus is 5.625m (roughly) while the scaled version should be ~6.4m. CW did that to make it compatible with stock otherwise people would have had trouble building it in the VAB without Hanger Extender.


    9 hours ago, CobaltWolf said:

    Draqsko, that's not the reason why I built it at that scale. THAT is a long story that has been lost to the sands of time...

    In the beginning  Cobalt said let there be a mod to fill the gap of Atlas, and lo, it was good. And Cobalt said let there be Titan and no Saturn, and lo, it was good. And the people lamented, and their cries were for Saturn. And Cobalt heard their cries, and was moved by them, and began Sarnus. And lo, when developing Sarnus, Cobalt cried out, for the game did not have hydrolox fuel support, and Cobalt was covetous of his mod, and desired not to have a dependency. And after much discussion, the decision was made to under-scale the Sarnus parts so that the Mighty F-1 engines would not need 90% of the thrust of the real engine to lift the stack. And Cobalt beheld this, and decided it was not good, and added hydrolox tankage to appease the masses, and they rejoiced for their rockets, and were grateful, until they went back to asking for Delta IV and X-20. - A Theatrical History of BDB

  11. On 7/13/2019 at 5:51 AM, dustinanglin said:

    I just recently started messing around with Realism Overhaul and was thinking about trying to recreate the Apollo 11 landing in honor of the upcoming 50th anniversary. Before I start banging my head trying to get a bunch of old craft files and other mods to play nice together, I was wondering if anyone else was planning on recreating the Apollo 11 journey and if so, what the latest and greatest set of mods and tools are for getting that done? Is FASA still the best way to go for Saturn V rocket parts? Is it better to build from scratch or use prefab craft files? Are there any mods that implement the AGC where you can input nouns and verbs and such?

    Thanks for any help folks can offer! :)

    BDB is great for a 2.5-3.2x scale system:


  12. On 7/15/2019 at 8:35 AM, Gordon Fecyk said:

    Been playing with FARc Mach on JNSQ for a while. As much as some folks turn their noses up at it in this thread, FAR doesn't change the atmospheres. It improves the drag model.

    I was going to show how dumb KSP's stock drag model was with a Bradley Whistance video, but it seems I can't find that three-part-challenge-to-Duna video where he took unfair advantage of the drag model by flipping parts around.

    Because it's a video by Stratzenblitz75, not Bradley Whistance.

  13. A few questions about the experiments:

    1.  When in storage, the the deployables (experiments, controls, power, ect) have mass that impacts the parent craft?
    2. If so, do the items being placed have a consistent mass, or does it change from item to item?
    3. Can kerbals be independently equipped in the VAB if they are to be seated in command chairs?
    4. Will kerbals in command chairs in general have the mass of the deployable item added to the mass of the vehicle they are in?
    5. Is the mass of the deplyable added to the Kerbal when they are walking around with it in their inventory (is this a way to make kerbals sink and not rise to the surface of the oceans)?
  14. 7 hours ago, Pappystein said:

    Ok I guess I have no patience... I waited a day for deets and nothing followed....   what is your project Jso?  

    I am guessing some sort of nav/comm constellation of micro-sats? 

    In the 1960s the US launched a series of 27 sub-synchronous orbit comm satellites under the name Initial Defense Communications Satellite Program. JSO is making the sats and their unique dispenser.

  15. 5 hours ago, kewcet said:

    So i have recently switched to Restock and the artstyle is perfect! However, some mods now seem a bit 'out of place' now. So my question: Which part mods would you recommend to use alongside Restock (and possibly the Near Future packs)?


    I would recommend Cormorant Aeronology as another Mk3-alike shuttle mod. It is scaled differently than both stock/restock and the BDB/Tantares/ReDirect/Knes, but it is a lot of fun, and is based on Porkjet-alike textures that were the original direction for ReStock.

  16. 5 minutes ago, Maxsimal said:

    To answer a few questions that have been popping up here:
    3. Mods will be able to add experiments for the surface experiments.
    4. To deploy experiments, you'll have a Kerbal grab them from a storage container, carry them in their own inventory, and put them on the ground - the type & experience level of the Kerbal will affect the performance of some of these parts.  Read into that what you will.

    Thank you for the explanation!

  17. 16 minutes ago, UomoCapra said:

    The deployable experiments will take measurements over time. and you'll be able to speed up this process by having specialized (e.g. scientists) Kerbals operating them. Unlike other experiments, Deployed Science will need to be set up like a base, where you'll need to take care of energy requirements and transmission equipment, as well as having a central station for  the experiments to work.

    You said 'deployable.' How are the experiments deployable? Are they movable/placeable with a Kerbal, or do we have to have a rover that goes around and drops them off with decouplers?

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