# Kerano

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Sr. Spacecraft Engineer

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1. ## Landing Delta-V Calculation

I've been working on an program to calculate combined takeoff and landing delta-v from a wide range of planet sizes (comets through superearths) and atmospheric thicknesses (vacuum through supervenuses). I'm reasonably happy with the takeoff delta-v calculation - a two-burn Hohmann transfer from surface to orbit assuming a vacuum, plus a term to approximate atmospheric drag. It's not perfect - it makes several assumptions including unlimited TWR on the rocket - but it's a decent first approximation. The landing delta-v calculation involves a deorbit burn and then a braking burn. Deorbit is easy enough - just reverse the circularization burn to bring the periapsis back to the surface. But the braking burn is more involved, because I'm looking to land a rocket capable of taking off back to orbit (not just a capsule). We can set certain limits. Braking delta-v can be as low as 0 m/s (super-thick atmosphere and/or tiny comet where descent to the surface is very slow) or as high as 110% of the takeoff delta-v (vacuum descent with unlimited TWR, allowing 10% safety margin). Between these two values - where the atmosphere is thick enough to slow descent but not to a safe landing speed - is where I could use some ideas on how to proceed. The rocket we're landing will vary greatly in mass depending on the surface gravity and thickness of the atmosphere we're dealing with. My initial thinking is to find the terminal velocity at the surface and use that to deduce the braking delta-v. This won't be the same as the terminal velocity on ascent though, because on descent there'll be more drag (rocket travelling rear-end first). Also, any parachutes will have much more of a drag effect on low-mass rockets than heavy ones. Clearly there's a lot going on here. I'm not looking for an exact solution, but a decent approximation. How do we estimate landing delta-v for a rocket - across a range of planet sizes - when there's not enough atmosphere to land safely without a braking burn? Any thoughts are welcome!
2. ## About those "Build a new orbital station" contracts

Fuel requirements can be pretty high, yeah. But these contracts tend to pay pretty well, so I don't mind too much. I picked up a 6000 liquid fuel contract for a Minmus station early on in my career - I just waited until I'd unlocked the ISRU to finish it. Still gave me a nice cash influx for accepting the contract. Fuel transfer via mining/docking just takes time. The trickier contracts to design for, I find, are the 20+ crew capacity ones - especially when they have to be on motorized wheels on the surface. Still a fun challenge though.
3. ## Sure, that's an unmanned probe

Haha, I probably could have toned down the self-lighting. Makes it look cool though, especially against the backdrop of Duna. (Panels are retracted in this one for atmospheric reentry.) I probably overdid it on the parachutes though. Takes ages to repack them all! Makes for a soft landing at least. Haha, pretty much. Main design goal was to try using the Poodle engine, which I've never given much love before. Turned into a quest to see how much ore I could retrieve from the Mun in one go. (195 tonnes of ore in one go incidentally, doubling the wet weight of the craft - with about 700 m/s delta v, easily enough to get to Munar orbit. Allowing time for the ore conversion it caps out at well over 4000 m/s delta v.) The Duna variant is adjusted slightly (4 ore tanks -> 4 fuel tanks) so it has enough delta-v to get to Duna orbit. Can only half fill the ore canisters when flying up from Duna, the full load is no problem from Ike though. Wide base keeps it stable landing on most surfaces. Carries 29 crew, handy for tourists - can easily be adjusted for more. My entire space program is on that one mission to Duna - I like to play it risky. Incidentally the rover itself has enough delta-v to get to Munar orbit on its own. (It can also reattach to the main craft.) Super fun to play with, many stunts around crater walls. At launch. Entirely stock. Can upload the craft file if people are interested.
4. ## Sure, that's an unmanned probe

Trouble satisfying contract requirements in your rover? No problem, just step outside a moment... Now that's a well paid EVA. (About your "satellite" though, guys... I think it's getting itchy feet...)
5. ## The v1.2 Hype Train Thread - Prerelease is Out

This has become my 1.2 prerelease anthem. Many Kerbal rocket launches have been synced up from 2:14 to the end.
6. ## Devnote Tuesday: The wait is almost over!

Fantastic! One of the main annoyances for me in my 1.2 prerelease career so far is that it took multiple Mun landings before I got offered contracts to explore Minmus, and multiple Minmus landings before Duna was put on the table. I mean you can go there regardless of the contracts (or sit idly time warping and hoping for the right ones to come up) - but it's so much nicer when you get a big contract reward for visiting a new place.
7. ## The v1.2 Hype Train Thread - Prerelease is Out

Seems the contract requirements for returning ore to Kerbin are... ah... a little loose. Noticed after launching a second mining probe that the requirement for "extract ore from the Mun" was already ticked, even though it was the first mining probe that was still busy on the Mun. Thought to myself "I wonder, what if..." and sure enough... On the other hand the contract requirements for docking and what constitutes a "new" vessel might be a bit too rigid. - Docking doesn't count for contracts or world firsts if the two vehicles started as one, no matter if they go on separate missions hundreds of kilometers apart (e.g. mining on the surface and docking back to the mothership). - When docking a newer vessel to an older vessel, the newer vessel can become permanently disqualified from the "build new ship" requirement (e.g. for a new orbital station) even if it was eligible before docking. Seems it inherits the age of the older ship.
8. ## The v1.2 Hype Train Thread - Prerelease is Out

Okay, discovered how to do it after some searching - double click orange bar in info box. Not as obvious as it probably should be.
9. ## The v1.2 Hype Train Thread - Prerelease is Out

Any way to reclassify ships that don't have a command capsule? I love rescue missions, but dislike the clutter it leaves on my tracking station screen. I prefer to relabel empty capsules post-rescue as "Debris" so they disappear from my tracking station, but can't do that when it's just a crew cabin. If it's not currently an option, can we gain the ability to reclassify ships inside the Tracking Station please? Thanks.
10. ## Video Wednesday: The Segway Incident 2!

Very entertaining, and nice special effects.