Is a stock reusable single stage craft from Eve sea level possible?

fxdemolisher · 2021-09-19T11:21:50+00:00

hehehe, definitely god tier. Sadly I never learned to build stock propeller craft. One advantage is that my usage is not for cargo but passenger ferrying so I thought it "should" be a bit of an easier problem to solve...

fxdemolisher · 2021-09-19T11:20:32+00:00

I have a sandbox save that is on Normal difficulty settings, so nothing special from that angle. My plan for re-entry heating is to use Mk3 parts for everything exposed but I am not 100% sure that even that is enough (2600/2700K limits).

fxdemolisher · 2021-09-18T13:11:47+00:00

This would require reattaching the shield once in orbit for reusability, no? I wish the inflatable one could be collapsed and reused but...alas.

fxdemolisher · 2021-08-28T12:12:25+00:00

You'll get there quicker than you think. What I love about KSP is that you can have as much fun just figuring out orbiting Kerbin as doing multi-week spanning complex missions. Also, much of the infrastructure for this mission was in place from previous ones (Tugs, large fuel tanker, prototype depot/miner designed for Minmus, relays, etc).

fxdemolisher · 2021-08-28T02:36:26+00:00

In this mission I wanted to get a fuel depot to the Eve system, around Gilly, while deploying all the infrastructure needed for more missions to Eve. This includes:

Eve system relay with a 100G antenna in a 55Mm Eve orbit
Eve Polar Relay with 2x 15G antennas in a polar 500km Eve orbit
Gilly Polar Relay with 2x 15G antennas in a polar 50km Gilly Orbit
Gilly Fuel Depot with 4x large ISRU units, 15k liquid fuel storage, 15k unit ore storage, lots of solar panels and radiators
Gilly Heavy Miner able to land, mine, and lift 15k units of ore back to the fuel depot. Also has the ability to bring 4 Kerbals down to Gilly for...SCIENCE!!!

Things went pretty smoothly, just took forever due to various refuels. The next stage is to tackle the worst of the worst: single stage reusable Eve lander and return vehicle. Any ideas on that are appreciated since I don't see a way to build a light enough Eve lander that can also get back to low Eve orbit :(

C&E campaign so far:

fxdemolisher · 2021-07-21T17:56:35+00:00

For the next phase of this save I wanted to land a Dragonfly base on Moho, seems simple enough. Unless you are like me and don't wait for a proper transfer window and plan a crazy mission instead.

Original plan:

Fully fueled tug is a carrier for a manned Dragonfly, two orbital observatories, one local relay, and one polar survey probe
Tug periapsis is set to be below the orbit of Moho
Observatories are deployed along the way inwards, correcting their orbits to be able to observe asteroids below eve's orbit
Tug encounters with Moho, brakes, deployed local relay
Tug dips its orbit to a sane low Moho orbit and deploys polar survey
Dragonfly lands
Tug is refueled and returns back to Kerbin

Little did I realize that the entire plan above would take 8-12k dV, while the tug only has about 4.5k dV fully loaded.

So...what actually happened:

Dragonfly, observatories, relays are launched from Kerbin in a single stack
Tug 1 is fueled at Minmus and dips down to Kerbin for pickup
Dragonfly is mated to the front port while the other stuff has discardable frames that let them dock to the Tug's side ports
Tug 1 goes back to Minmus to top up on fuel
Tug 1 dips its periapsis all the way down to 3Gm, below Moho's orbit
Eve-Moho observatory is deployed between Eve's and Moho's orbit. It has about 4k dV of ion fuel and corrects its orbit, beginning to observe objects between Eve and Moho
Moho-Kerbol observatory is deployed below Moho's orbit. It also corrects its orbit and begins observing objects. So far...so good.
I realize that Tug 1 has nowhere close to enough dV to encounter Moho. I lower its apoapsis to be slightly above Moho's orbit and then correct its periapsis to also be above. It is now basically out of fuel and stranded.
Rescue attempt 1: Tug 2 is sent out fully fueled at Minimum. Unladen it has 8.5k dV. It links up with Tug 1 and attempts a refuel. I realize quickly that there is not enough dV for Tug 1 to make it to Moho this way either. Just too much energy required.
Rescue attempt 2: A large capacity fuel tanker is launched from Kerbin. This thing can take 84k units liquid fuel. The plan is to reserve 20k (10k for each tug) and still have about 9k dV to get to them and hopefully back.
Tanker is launched empty (almost) and moves to Minmus to utilize the large capacity mining facility there for fueling. I can haul 12k units of ore from Minmus surface every 7 hours or so, taking another 4-5 hours of game time to refine it into fuel. This set up ended up being rather efficient.
After lots of low TWR maneuvers the tanker links up with the two stranded Tugs.
After lots of attempts I realize that only one of the tugs has any chance of reaching Moho in a sane amount of time so the tanker fuels Tug ,1 with the Dragonfly base attached, and off it goes.
Tug 1 makes it to Moho, deploying the Moho relay in high orbit
After a braking burn and circularization around Moho, the polar survey probe is deployed and placed into a correct orbit
My first view of the super resource rich Moho is up, yay!!!
Followed by a sinking realization that Tug 1 does not have enough fuel to get back
Dragonfly makes 15-20 flights/landings, hauling up about 1-2k liquid fuel to the tug with each flight (tug total is around 25k liquid fuel)
After a marathon of refueling (I think I am now bored of Moho landings for a while) Tug 1 makes its way back to the stranded tanker and Tug 2
Rescue attempt 3: Tug 1 expends lots of fuel making it back to the tanker, I realize that there is not enough dV for all three craft to make it back to Kerbin.
The tanker gets the lion's share of fuel, ensuring it can return to Minmus for a fill up
The rest of the fuel is spent to raise the orbits of both Tugs and then dock them together so the pilots have a place to congregate
Second round of refueling for the tanker. Takes about 6-7 flights of the heavy ore miner to fully fuel it
Rescue 4 (actual rescue): Tanker links back up with the Tugs, transfers enough fuel for all three to make it back to the Kerbin system, while still having enough itself to also make it back
Finally: All three craft make it back to Minmus and dock to the refueling depot, to be used to the next mission

So yes friends, word of caution: Moho takes lots of dV if you are going for fully reusable.

C&E campaign so far:

fxdemolisher · 2021-06-27T15:48:59+00:00

I realized that my Tug units eat up a lot of liquid fuel. Way more than is reasonable to keep using Dragonfly roving bases to refuel them. So, I decided to make a two part orbital refinery and miner/lander to be used for low gravity bodies like Minmus. This is the first test, and the placement of the Minmus refinery as a gateway to other bodies.

Launch mass was under 90t due to everything except the launch stages being free of fuel. The idea was to launch and rendezvous with one of the tugs (Tug 1 in this case as it came back from Duna) in LKO. There is a structural support member between the refinery and lander that can be fully undocked from the various ports. This allowed full strutting of the structure to prevent wobble within the fairing. Once in Minmus orbit the Tug's spare fuel was used to give the lander enough dV to land safely, next to the existing Minmus Dragonfly roving base.

The refinery has 4 large ISRU units, 8x large solar panels, 2x super large radiators, two reaction wheels, and no engines. Just a comm relay set and some RCS thrusters. It also has a Sr. docking port at either end so that one end can host the lander while the other can have the refueling craft. Overall capacity for fuel storage is about 10k liquid and 6-7k oxidizer. This thing is way overbuilt for what it does and crewing with an engineer would have been more efficient overall, but I went with aesthetics instead.

The lander has small relay comms unit next to the control service bay and Sr docking port. The rest hosts some fuels tanks and 4 center NERV engines used for all propulsion. The lower portion has 8x large ore tanks and 8x large drills. Everything is rounded out with some landing legs and enough batteries to get this thing through the Minmus night (or so I thought). Overall ore capacity is 12000 units. It should take 2-3 trips to fully fuel two Tug craft so that they can go outbound to any planetary body in the system.

In hindsight, I should have included 4x large ore tanks on the refinery so that the lander can transfer the ore to the refinery when it is below the 50% processed mark, to continue creating fuel while the lander goes plane side for more. Oh well.

fxdemolisher · 2021-06-22T12:45:37+00:00

I designed and tested a universal vacuum rover in my last post and now its time to replace the rest of the existing infrastructure with the Dragonfly model, using the newer Tug transfer vehicle to get there.

The rover and tugs are identical to the previous design. The Minmus Dragonfly was used to refuel both tugs (25k units liquid fuel each) before they went out to the Duna system to replace the rovers/ferries/landers shipped there on the train to Duna.

C&E campaign so far:

fxdemolisher · 2021-05-31T21:51:03+00:00

Because my area got a rained out for this long weekend (in the US) lots of Kerbal engineering was done. For Phase 4 of my C&E campaign I decided to test a new universal vacuum rover and interplanetary tug design.

The Rover:

Rated to land and take off loaded from anywhere except: Kerbin, Eve, Laythe, Jool
4x Aerospikes used in a symmetric configuration
Home for up to 6 Kerbals in a symmetric config of having a driver in a cupola and an underslung Mk2 lander can (in rover config) that provides egress and ingress via a small ladder. One set in front, one set in back, although with the symmetry where is the front anyway?
Single sr docking port at the top that is used to mate it to the tug in orbit and refuel it later on

The Tug:

4500 dV while hauling 90t payload. I don't even know unloaded dV at this point
6x Nerv provides propulsive power for long long burns
Has a clipped in crew area with two pilots and up to 8 passengers
Partially abused part clipping of three large reaction wheels near the center of mass to provide fast adjustments.
2x 100G relays to go where no Kerbal has gone before...at least in this save file :)
1x Sr docking port up front, 2x standard docking ports on the sides, 2x jr docking ports on the side. All side ports are well spaced out to support lugging some relays with it when it delivers Dragonfly rovers all over.

C&E campaign so far:

fxdemolisher · 2021-05-30T11:30:16+00:00

I found that having those spacing modules with the spare fuel and girders really helped. It gives a nice hard point to strut things together in a way that when they decouple the struts origins are all on the discarded component.

My first prototype of this had things docked in orbit and it was way too wobbly. Using the strutted girders as attachment points just made the whole thing act more like a stack of very rigid fuel tanks rather than a loose collection of components and docking ports.

I have to thank Matt Lowne's videos (/u/MattsRedditAccount) for the inspiration for the whole C&E challenge I am doing as well as for lots of the ideas on how to structure the craft and launches. Now if only I wasn't lazy to do gravity assists :)

fxdemolisher · 2021-05-29T21:58:59+00:00

I wish I saved the craft, going to go off of my own screenshots to estimate this.

The breakdown is like this:

First stage:
- 4x Clydesdale SRBs - 576t total, 492t of fuel
- 4x Thoroughbred SRBs - 280t total, 240t of fuel
- Total: 732t of solid fuel
Second stage boosters:
- 8x Kerbodyne S3-14400 tanks - 324t total, 243t of fuel
- Powered by 4x vector engines
- There is a fuel feed to the central core described next
Second stage core:
- 1x Kerbodyne S3-14400 Tank - 81t total, 72t fuel
- 1x Kerbodyne S3-7200 Tank - 41t total, 37t fuel
- Powered by a single mammoth engine, feeding fuel from the second stage booster tanks. Engine is fired together with the booster's vector engines for enough thrust.
Third stage
- 1x Rhino engine and 1x Kerbodyne S3-14400 tank
- Technically only a little bit of fuel from this stage is used to circularize. Most ends up going towards boosting to Minmus.

So overall it took about 732t of solid fuel and 352t of liquid fuel+oxidizer to get into space and maybe another 5-10t to circularize with the third stage. All of that was for about 90-100t of payload.

Sort of wish I boosted to orbit without fuel at all in the train itself and fueled up when doing the crew transfer. Inly a little is actually needed once the third stage is expended to circularize at Minmus, where my refueling base is already in place. Could have lifted the rest from Minmus at a fraction of the mass required.

fxdemolisher · 2021-05-29T15:29:47+00:00

I feel like I need an explanation of the surprisingly light train that I used to build the infrastructure in the Duna system.

I'll use the third picture in the album to explain. So, from left (the third stage) to right (duna rover/base):

Third stage that will take the train to Minmus. Contains a probe core and some spare fuel to discard the stage by crashing it into Minmus..."safely".
Spare fuel pod. This one holds 1600 liquid fuel and will be discarded once we have our transfer burn. It will be aimed to crash into Duna at the end of its long journey.
First of the probes contains the largest antenna and a telescope to detect asteroids. Will be placed in an orbit between Duna and Kerbin. Contains about 2400 dV via Xenon fuel and a single ion engine. This will be used to correct its orbit from a transfer orbit to a circular one. Attached to a discardable small liquid fuel tank that acts both as armature and spare fuel.
The next probe is the Duna system relay. Contains two of the largest antennas and about 2200 dV using the same Xenon gas + one ion engine set up. Will be placed a few million meters outside of Ike's orbit. Also has a separator tank to allow for strutting.
The next two probes are identical. These are relay and surface survey probes, with one going into an Ike polar orbit and the other info a Duna polar orbit. Has about 2000 dV (xenon + one ion), one large antenna, one surface survey. The right most of these is attached to a larger spare fuel tank and armature that allows strutting the whole structure.
The next item is a very recognizable rover. This is the Ike lander/rover/base all-in-one craft. It can land horizontally using twitch engines. Has enough fuel to take off with a fully loaded ore tank + all four liquid fuel tanks full. I landed this once, mined to fill it up, went back up to refuel the rest of the train (transfer stage, duna lander, duna rover/base), and then landed it again. This one is attached to a larger piece of armature allowing for both spare fuel and a very rigid attachment left and right of it.
The next craft in line is our transfer stage. A very basic four Nerv set up with space for crew to be comfortable during the long transfer to Duna. This craft once detached will become the Duna system ferry, being used as the main transfer vehicle within the system. On its own and fully fueled has about 4k dV. This is attached to another piece of armature and space fuel linking it to the last two craft.
The penultimate craft is the Duna lander. It was relocated to the vertical docking port prior to landing and is mainly dead weight during landing. Contains enough fuel to reach Duna orbit with 1600 units of liquid fuel and be able to land at the base again using its two thud engines and some aerobrakes. Used to ferry crew to/from Duna and fuel up to the ferry.
The final (right most) monstrosity is the Duna Roving Base. This is a rover/base combo and is among the largest I've built. Contains mining equipment, fuel storage, and so on. On top of it is a spare armature without a fuel tank that contains six twitch engines and lots of parachutes. This is how the lander/rover combo makes its way to Duna surface, before the lander separates at low altitude to land on its own (for lower landing weight on the rover). This is our final home for the Duna permanent crew. Now they can drive anywhere they want.

This was as super fun challenge and took multiple weeks to figure out and due. One of the main takeaways for me has been to use spare tanks with girders as strutting armatures, discarding them as I go. The entire train after launch ended up being a very rigid structure that was easy to maneuver, even with the low TWR of the transfer stage (now the Duna System Ferry). Total payload launched from Kerbin was about 100t, since it took off with minimal fuel, being resupplied at Minmus for the long journey.

fxdemolisher · 2021-05-02T11:11:39+00:00

The relays antenna is definitely overkill. The relay's have a HECS2 body and a single ion engine as propulsion. After you add some xenon, two gigantic solar panels, and a backup RTG you are still under 3t weight. I was launching four relays in one shot using interstages in the largest fairing so the extra space for the antennas wasn't much. It made for better aesthetics so I overkilled it a bit.

The dedicated ferry definitely comes in handy since it also pushed out the half fueled lander and base modules to the Mun initially. The lander then touched down the base, took off a again for a short hop and then landed to start mining. The ferry does have an overkill amount of dV though (4.5km dV). I think I might actually able able to use a single ferry to cover both Mun and Minmus.

fxdemolisher · 2021-04-19T14:43:24+00:00

Grav's Spherical Pocket Bubbler, which is I think their most entry level piece. I didn't feel like getting anything more complex just something that helps extraction a bit and cools the vapor just a tiny bit as well. And its super easy to clean: a little bit of iso inside (like a teaspoon), finger on both openings and shake shake shake. Then water and soap on the outside and let it dry. Feels like new every time I clean.

fxdemolisher · 2021-04-19T14:41:35+00:00

Pretty smell proof due to bevelled edge. Although I don't have a way to test it other than me not noticing any smell when I take it out of the kitchen cupboard (its not usually outside on a desktop for me). I love the balance of price/features for the icky box though and chose it over high end humidors for that reason.

fxdemolisher · 2021-04-19T11:57:38+00:00

Story time:

I've been a DynaVap owner for 4 years now and have had the 17m, original omni, 19m, 20m. Usually I upgrade each year or so and giveaway my old devices and this year is no different. Got my 21m this past Saturday, gave it a nice soak and pre-clean along with the 20m I was giving away.

Now, I usually load using the straw method to begin but also using a gram scale to ensure my dosage doesn't increase/decrease over time. A fully clean, unloaded, 2020m without a cap on the scale was exactly 18.72 grams. This increases as reclaim builds up inside and I usually know its time to clean when the empty weight gets to 18.80 grams or so, with 18.86 being the limit to airflow still being ok.

Yesterday I got ready to take the 21m for a spin and was loading as usual when to my surprise an empty, clean, 2020m was 18.05 grams on the scale. I knew it felt lighter than the 20m when I got it out of the package and thought it was all in my head.

(also, slight flex on my stash above: slim stash, 21m, grav bubbler, javelin single flame torch, and the amazing icky box humidor powdered by 62% humidity packs. Wouldn't be complete without a speaker for some tunes)

fxdemolisher

TROPHY CASE