paul_c

If you are doing it during ascent, then decouple a front tank then pitch down, wait a few seconds and burn again. If you are doing in during orbiting, then turning retrograde makes sense and you get the little bit of energy from the decouple too. Basically, fire it in any direction EXCEPT the one you're about to fly towards!

Indeed, they are entirely calculable, and intuitive to do. I may look at the mod at a later date, thanks for the suggestion.

Lower, for 2 reasons: Oberth effect, and also a shorter orbital period means you can choose the time to burn/which orbit to burn (which is handy if you timewarp and oops go past...) without the target having moved along as much. There is a technique to do a series of multiple burns. Of course, the last burn is the one you "shoot for the target" from, so you need to have made an allowance and the burn before, needs to take into account both 1) the extra time for this previous orbit and 2) that the previous orbit is itself, a bit elliptical, being 'half way there' or whatever, takes a longer orbital period in itself. The most I've done is 6 burns......and no, I couldn't work out where the eventual ejection occurred, I relied on random chance and/or just waiting an orbit or two for the moon to come round again!

Strangely, the key to progress has been unlocking and gaining access to the T400 fuel tank. The lower part count means I'm not squeezed on science kit or batteries. So, yet another design iteration means I've optimised it for transmitting data. Minmus' performance requirement is ironically less then Mun (due to its slower de-orbit-to-land speed) so I went there first: Minmus Great Flats: Poles: Highlands: Slopes: Then a Mun-specific tweak (less aerials, more fuel); Mun Twin Craters: Mun NW Crater: I need one more successful Mun trip then I have 90 science points and can do the next tech upgrade. I'm 99% sure I'll actually go for "Miniaturisation" before "Electrics", because it buys docking ports and it means the remaining Mun/Minmus trips could be made dual-purpose, to immediately transmit some more data and also re-orbit for later recovery for full points. This should save on the total number of Mun/Minmus trips, which I understand from previous NCD attempts, gets very grindy.

Its an interesting thought - whether you can influence a commercial company to alter its methodology in a fairly detailed aspect of their core work - by petition. I am sure companies do listen to feedback and have "customer satisfaction" fairly high up the agenda, but for things like this they would need persuading quite a lot; or quite a lot of customers to raise concerns - to change tack. Good luck though.

Produce (very polluted) thrust from the nozzle?

Pragmatically, you could do it with something other than a rocket, eg a paddle wheel or propeller. At 95 bar, the viscosity of Venus' atmosphere it going to be like a thick mud, so blasting a rocket to high speed seems terribly inefficient.

I would have thought lower flowrate (due to viscosity of fluids being greater, due to pressure inside (and out) greater) --> higher temperature for a given burn rate --> higher burn rate --> higher temperature internally --> higher pressure internally --> higher pressure differential --> (it would increase flowrate but not by much, no where near approaching flowrate of rocket in 1atm). So, it comes down to a materials science problem - you'd need a casing which can withstand the higher (differential) pressure and temperature. Or alternately, you simply couldn't burn an SRB for as long, you'd need to have many stages of short-burning rockets. Because - even though I suggested some sort of equilibrium may develop - I suspect what actually happens is the temperature and internal pressure increase quite rapidly as the burn progresses, so the limitation or likelihood of uncontrolled explosion/rupture of the casing or seals is greatest towards the end of the burn. And of course, for weight/cost reasons, you'd not overengineer it, rather you'd precisely model the end temp/pressure and choose your material to withstand this (plus an engineering margin of safety). Sure, a rocket for Venus liftoff would look and be very different to one for Earth.

I am not sure the burn rate of a SRB would vary with pressure. I could understand, maybe with temperature as the fuel heats up from conduction/radiation too, but not from pressure since solid materials don't particularly have "pressure" in the same sense that a fluid does. Gaseous reactions' rate of reaction varies with temperature and pressure because the molecules are faster/closer so more is in the free radical state and more collisions/opportunities for molecules to interact, occur. But within a SRB, the reaction is a deflagration of solid components upon contacting the flame front.

The problem is, you can't just take a single value for the "pressure inside a Shuttle SRB" - because its an open, dynamic thing where combustion products are flowing out of the nozzle in the direction to give thrust. Venus' atmosphere is ~95 bar at the surface, so obviously there's going to be a number of physics effects on other components from the high pressure. But let's assume for a minute that the SRB doesn't implode or structurally fail etc. Effectively the burn rate of the fuel is a controlled explosion. With the extra 'push' of the Venus atmosphere trying to get into the SRB vs the burning of the fuel inside it, there will occur an equilibrium of sorts where the pressure inside rises and rises until it exceeds the outside pressure, then the hot gases will flow out of it at something >95 bar. They'll flow much slower than on Earth (1 bar), so for a given burn rate the energy*, thus temperature, thus pressure, will be (much) more inside the SRB than it would on Earth or in a vacuum. I suspect what would actually happen is the associated temperature would be too great for the materials to handle; and if you really wanted to launch off the surface of Venus, you would need a very differently specified and constructed SRB to do it in its 95 bar atmosphere, although the principle of rockets is the same. * ETA, the burning of the fuel converts chemical energy to potential energy (of a hot gas) at a certain rate. That potential energy would not convert to kinetic energy so much, because of the lesser flowrate of that gas. So there would be more gas, more potential energy inside the rocket's interior before it left the nozzle - it would all eventually come out, over a longer period of time. Less thrust, but not zero thrust.

Not much to report today. I tweaked the design, then went for a 3rd attempt at recovery back home, of Minmus science data. It failed again. Once I added heatshield/science store box/chute/decoupler, the parts count is too limiting. I had traded a little battery power for more fuel but it still wasn't enough, furthermore I could only transmit the "Goo" reading so less of a success than the 1st mission (which didn't return but transmitted both SJ and Goo). I've spent a lot of the day planning, in particular I know visiting the 17+9 biomes of Mun/Minmus, potentially multiple times, is going to be a slog. So I've been trying to minimise these. I could save 3 potential trips by going for docking ports earlier (then a trip can be a dual-purpose, transmit and later return). And depending on the nature/ambition of the Duna/Ike/Sun trip (which will be required) I may save a lot on the need for further Mun/Minmus trips for crew reports. So its looking up - I can plan to be efficient, rather than simply worrying about "is it possible". Of course, the Duna trip and much of the techniques there remain untested, but my Diamond run gives a fairly good idea on getting the spaceship to send there, more/less right.

Ok no worries, I can't really help much further. Good luck too!

I don't think we're on the same page here. 4 satellites, can & do produce a stable, 100% coverage all the time everywhere, constellation. It is not an "absolutely precise" thing where they need to be in an exact position (and maintain it) otherwise it drops to 99.9%, there is a ton of slop in the positions. The eccentricity is used to maximise the slop, for pragmatic station-keeping or fuel-saving, or ease of putting into orbit concerns in the real world. That the "shape" formed by the 4 satellites is in itself rigidly stable and unchanging, is not a consideration. Obviously, because all 4 AREN'T on the equatorial plane (maybe 1 is though) they are not geostationary. ETA Don't confuse a 4-satellite constellation with Molniya or Tundra orbits (which use high eccentricity to provide high % coverage of a portion of the globe per satellite).

Maybe But it doesn't matter.......4 satellites can 100% cover a body (for comms) in a particular orbital configuration. I can't even visualise that configuration, so I have no idea if the shape remains stable or morphs etc. I do know that in the real world, if/when the 4 sat config is used, slightly elliptical orbits are actually used, because it maximises coverage in the face of inaccuracy or peturbations.

There is also the option to "git gud" and learn how to do those contracts you find "undesirable". It is not a race, there is no timer - you can spend a day, or 2 minutes, on each contract and achieve something you want to.

It begs the question though.....for NCD, do the "little extras" alter the needed missions (a lot)? For example, Kerbin earns (max) 109.27, Mun earns 547.5, Minmus earns 386.25, Sun (high) only 15 leaving you 129.98 short. I've not included contracts or world first science - I'm not sure its significant anyway. Would the extras mean interplanetary is not needed? That would be a game-changer. I suspect gathering and returning science from another planet is an order of magnitude harder than Mun/Minmus trips. Without the precision of manoeuvre nodes, you need to do some funky stuff or pack a bunch of excess fuel, to make the encounter. And do it again to get back safely.

(For the OP) What are the basics of doing a rendezvous?

The Wiki doesn't have much on it - it definitely drops off with lower %, and from what I've seen its also non-linear. I think someone tested and documented the drop off but I can't remember the thread now.

I wouldn't do it right now either. If you've been 5 years since the last PC, 5 1/2 years will be okay too. Its a bit "crystal ball" looking ahead, but in theory the current generation of graphics cards ought to become more available; and something like a 3060 would be a good call (if/when they actually become available for normal people to buy).

Fitting a Communitron 16 then relaying it through 1x HG5 normally produces terrible comms from Minmus. I have an old craft with 1xHG5 and the relays have 4x each. I could retract the relay's aerials, to lower the commnet performance, do a bunch of contracts, then restore the performance. Or perhaps having something on an elliptical orbit, and waiting until comms drops off, then timewarp until its only just back? But really the answer is to tactically leave 1x craft in Mun/Minmus orbit/surface each (total 4) which has solar panels and a thermometer, to mop up those contracts for free science. Once solar panels are bought its a non-issue.

1. Tracking Station 2. Click on (eg) "Mun orbiter" 3. Click "Fly" button 4. Right click on the thermometer 5. Click on Log Temperature 6. Click Transmit Aaaaaah, 6 clicks! Still, its a nice way to make ~£5000. Up until now, even the better "test xxxxx at yyyyy" pay ~£2000 and need a vessel constructed or tweaked, then flown, then the descent at 3.4m/s on the chute. And "test at launch pad" pay about £500 max. Contracts can be selected as appropriate because there is no penalty for declining others. I am looking forwards to the "put satellite in orbit" because they pay about £10k and you can often do 2 of them on the way to something else, what with the requirement to stay in the specified orbit for 10 seconds!

I did a calculation a while ago, the ISP of mono/RCS was a bit lower than liquid fuel, so I've never fancied it that much. KSP doesn't report the deltaV of mono either. Docking ports are definitely on the list, its just a case of when not if! Anyway, my back-of-the-envelope calculation said I can unlock all of Gen Rocketry, Electrics, Miniaturisation just with transmitting (no return needed) so (I think) its more of a nicety to maximise science-per-flight, rather than a dead end to avoid. Obviously, return trips are needed at some point anyway for NCD, so its my focus for now.

I am glad of the Diamond (and Hard/Topaz) docking experience. In the end, I was pretty happy with just the main engine, and RCS would be a luxury which consumed weight and parts. I might want/need it much later if/when I can unlock further nodes but not complete the tree. But for now, its still very basic tech. Its a case of "why can't I do it now" and "what does the next node get you that will change the situation". Docking ports might not buy me any real advantage (at the moment) because its twice the fuel but twice the weight, etc.... I'll need to carefully design a future craft on paper then evaluate it as a "desk research" project rather than actually fly it.

To add, if you suffer a "% due to imperfect comms link" loss in science points, there is a silver lining to the cloud in that the electrical charge needed to transmit it, (seems to) scale down in proportion to the science points too. Strategically its an edge case, but if your vehicle had batteries and no solar, and you could somehow (maybe by design) make it so the comms was poor, it could do more "science from ........" contracts before it went dead. Handy for the early Mun/Minmus exploration, where solar isn't yet unlocked and that style of contract pays well for the time/work spent doing them (about 5 mouse clicks).

Of course, for any rendezvous, you don't actually need the inclination to be 0; but you do need to have the "encounter" at/very near the AN or DN, to be at/very near* the other body. And the further it is from 0, the greater (that component of) the velocity is. For planetary encounters, this results in an inclined orbit so long as you entered its SOI. The less the difference in inclination, the more likely an encounter is, ie it can be less precise in other aspects and still enter SOI. * 'Very near' could mean, within that planet's SOI; within range to do a manually flown docking approach; or to contact it directly. It goes without saying, you don't actually want to contact the planet directly, most of the time you'd want to not hit it but have a low Pe to minimise the retro burn for an orbit. But you could go direct if you really want - you'd not have much choice of landing site though.