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1.2.2 RSS to Venus manned return mission (WoT)


Bornholio

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Venus she's easy! or maybe not. She's hot, and has great tracts of land. Not that its a high pressure arrangement to sample her wonderful science. It will take more time to float to her surface than to do three full moon missions.

 

Playing a Career mode game (Hard setting except for load/save allowed) using RSS as my baseline mod. This is a 1.2.2 game so I’m using SMURFF, SpaceY and other mods to get to an acceptable power to weight ratio for launches, Using tweakscale and procedural fairings, SXTcontinued and near future mods for extended tech tree parts, community tech tree and SETI for an unmanned first push, TACLS for life support and I'm full enforcing a cleaned up orbit ( If i have to delete space junk it costs me 100k funds) and use Stage Recovery to get funds back (Set 7k Burnup Speed and 7-14m/s Landing, otherwise default) I tested various re-entries to make sure the 7k Re-entry speed was actually survivable for my designs. SCANsat and CactEye pad out the game but I’m using Comnet with only KSC ground station instead of RemoteTech for communications. Um oh and 104 mods in my CKAN installed list total... I have Saturn Second stage Nuclear and Timberwind nuclear engines in custom modded items, generally don't use them, specifically only on missions leaving from above 500km orbit.

None of the designs is dangerous outside of the basic nukes in space argument. I use a minimum of 12m from crew compartments as a design requirement for nukes. Some of the more extreme nuclear engine design would warrant more though. If I’m using a Timberwind 450 the engine is likely 30m+ back just because of the amount of tank it needs to be useful. Regardless once i get the SSME available it was all that for main and second stages. I use Solids only if really needed or its a real simple mission.

 

After Luna I started deciding what to do next, mars window was way out and I started to investigate Venus first. Time to set up comms. I probably could have got away without the comnet first but I believe its the first step given how many missions have failed because communications are crap. It also eliminated the need for huge antenna on the landers and probes.

COMSATS

Venus Comsat Network, sent 4 relays in an array planned aero-braking to drop dV, middle of aero-brake maneuver, deflated heat shield, and ejected compacted relay sats, barely staying out of atmosphere, each sat had barely enough maneuver 680m/s to get circular in a reasonable Eq. orbit.

zztyUzC.png

in trying to switch craft during the near disaster, got locked onto the structural frame that the relay sats coupled to during transit, (just some pipe sections a de-orbit motor and small probecore, mechjeb, antenna and batteries, one small solar panel). nothing burned up, very close but high drag really slowed it down fast. followed to ground, it litho-braked with the sacrifice of one of the spent couplers and I got my first Venusian data (telemetry & temperature). The Comsats got me a few more experiments and squarish 1200km orbit network (Intended to be 3000km).

FElCVY7.png

SCANSATS

Scansat probes went out next, didn't have SAR yet. Radar altimetry, Biome scanner and Survey scanners along with High orbit and Low Orbit Science Sats, discovered that venusian day is longer than its year! Very long scan time, skipped two useful transfer windows.

As the last of my Apollo moon missions finished scienceing the crap out of the moon I sent a second science/Scansat wave. SAR high altitude, recon and Survey detail sats along with my missing space science. Took a while to get all the gravity scans. Kerbal Alarm Clock estimates took front stage.

My first comsats & scansats went to mars during this time so it was hectic.

Descent to the surface! Originally I had intended to ignore Venus landings unless the were historical missions from RSS Historical missions pack. However the ease of landing space junk on the surface made me prioritize it given the shorter transfer and delay times for manned missions and sample return.

Venera Missions, first two missions sent using my best guesses and did not include all the instruments since I did not have all at this point, using DMagic's instruments also. Midlands for the win.

Stopped using the Inflatable shield because it was to hard to control drag, and it flipped on my first mission, lucky that a couple of solar panels was all that was lost. Landers overbuilt soviet style. Found out parachutes won't deploy at 12m/s in 70atm. drogue shoots in pre-deploy would not stop spinning, but full deploy brought the landers down straight. Any lifting surface is detrimental to landing except maybe airbrakes/gridfins. Reality is that they probably melted on the way down since they didn't include temperature control of any kind. past initial re-entry anything that is dropped will make it to surface probably with a safe speed (kinda 12m/s seems like max on higher terrain).

 

Major Probe Volley!

After re-design of the probes, left me with R2D2 looking canisters filled with science I tried sending two for testing. Mainly finding more accurate landing position. The agonizing wait during the drop! don't like x4 physical landings regardless of speed, read a book, made some tea. Determined that below 50k altitude ASL engines are indeed totally useless. Determined total batteries i could get away with. Solar is great assuming they survive re-rentry heat.

Next eight came in as a docked cluster. Horrible experience with all eight lagging my computer.  They consisted of unmanned landers, transmit only, everything possible to fully transmit, all biomes.  Still very slow descent, probes hit 11m/2 without drogues, tiny landing gear, set of small airbrakes.  Temperature was not an issue, though activated thermal panels cooled the pods.  Even at 4xphysical time warp the descent was horribly long, cheated gravity to x10 for the 4th and later probes just to lessen the real time spent on the mission, took over 4 real hours to get all biomes sampled. Noticed during the first and second mission that engines and RCS became useless for anything except re-entry phase, determined 300-800 m/s of retro and 40-50 RCS got a good accurate landing, both mechjeb and trajectories projected over shot landings. Rovers might be faster than planes on venus. Trajectories as usual seemed more accurate.

I11ltYT.png

 

Sample return!

Attempt one consisted of a real simple pod, stack of ascent rockets, stack of batteries and eight ducted fans. ran out of batteries at 20km, drag was to high for the system to get up.

Second try replaced most of the batteries with capacitors and almost made it. The ducted fans didn't have enough thrust to get me above the point I needed for thrust on my bottom stage (4xlarge Ullage motors with flat ISP). floated back down.

Third try, nukes, capacitors in drop pods, more ducted fans (too many). the ducted fans started crashing the computer with some bad interaction of mechjeb's dV calculation. Think it had something to do with staged capacitors, the ducted fans and some kind of circular calculation. After 12 program restarts including one full on computer freeze I gave up on the ducted fans. I think it can work.

Fourth try, Balloons! Used the HL inflatable parachute. Made it too small. I didn't see the dirigible icon in VAB so I undersized the balloon and it wasn't enough to get me up to 50km. Also discovered the kraken hates unbalanced balloon lifted craft, spinning it until my probe core sped off at Sol escape velocity.

Try Five. Bigger balloon, used RoverDude's control pod. was great but in dropping from the balloon frame I clipped a tank and blew up.

Try Six. made it to orbit. Barely 165x147km Orbit and forgot a docking port. Using a Timberwind 45 design basis Nuclear rocket for everything except initial separation and orientation. Tumbled a lot, need cleaner separation and deploy-able control surfaces. Spinning and very slow ascent to be safe enough. Agonizing pain of slowly changing inflation of the balloon as the velocity dropped below 10m/s. Going above 30 resulted in explosive spin (actually five iterations of this design blew up on ascent) because I got impatient and inflated too fast.

Try Seven. Changed balloon “Cirrus” real lift variant, started including life support (TACL) and more support in general. (return vehicle prepositioned in 350x350km EQ orbit). Lift vehicles started passing 500k for the missions, plus one 180k refueling mission in my planetary band parking orbit. Determined need for 140+ days on orbit life support and ~100days transit (3500m/s dV transit + 3000dv to bring it into parking orbit for re-use). So generally needing 13k dV for fast missions. Total life support of near a year. Loaded Solyent Green/Red life support mod for TACL. Tested 5 iterations most problems were hard to control on drop, re-entry. Had one burn up too bad for use, two had hard landings as they came in at an angle and fell over.

Try eight. After a successful orbit and rendezvous and realizing my rcs balance and SAS sucked on the final manned return pod, removed all but 5days LS from pod.  Pod is located inside a set of cargo-bay modules, Three cooling stages are included, larger amount of RCS. Has about 1200dV to spare for any orbital maneuvers. First unmanned test, drop from balloon at 0.35atm, drop first stage tanks, drop second stage tanks, drop third on way to circ burn, mechjeb ascent.... takes me in 180deg counter orbit. 14kdv to get plane change. /sigh

Second test I get to balloon separation and drop, launch and start up, run into balloon and explode.

Load and try again, manually pilot, then beginning the ascent guidance to nice clean 350k orbit.

 

Try Nine. new design includes sepatron to get balloon spun away from vertical. Full flight plan unmanned test including return using a large nuke powered 5m transit bus. Optimized the balloon to get a stable point of 100m on earth, gave me >1atm on venus lift final so ascent using my normal motors is possible, Used timberwind 45 again as ascent motor and staged the tanks on layered side pods.

Transit bus includes LS reprocessing, cargo bay with supplies and excess life support equipment space for 3 crew (Intended for one man missions) that includes an earth orbit return pod. Is 10tons of Fairing excessive? 750k funds to orbit, a refueling and off it went. Mission went great, max inflated to balloon from ground level, it goes supersonic immediately and starts climbing fast (150m/s peak), drop the science and landing gear stage just as take off happens. Nice stable verticle ascent with a little wobble. Fins might help be they are hard to include. Ballon shot clear and spun off to the side, ascent arced nicely past it and almost all my spare dV went unused. Docking went a little rough, not sure if its the Covered Jr. docking ports I used. So now I have an extra emergency return vehicle in orbit.

5million Funds well spent. Time for Real Manned Mission(tm).

 

Manned (Womaned) Mission!

jHaMsgc.png

Valentina did the first mission solo 144days of waiting, 96d+102d transit, 5 seconds of EVA (hot hot hot), and many minutes of up and down above venus. Now for 7 more times, all in transit, Valentina sits in the abort return vessel.

A spare lander is coming along also. Rescue mission at worst case or if I miss a biome target. Best case 1.2m worth of orbiting space junk. Thought about exploring using a rover or folding aircraft, but its way to slow unless I’m right on a boundary even then its a serious mission to get one and also have the balloon launched rocket in the same place. I kinda doubt i could even get close enough for a rescue mission to actually work. Should have positioned a grapple rover to avoid to EVA problems (fire clad space suits).

Now on to more missions, to places like the canyons (looked kinda dunish to me) as harley kerman plants his flag...too hot, oh well maybe just the EVA report. I wonder why he had that red bar over him during his EVA. I think I heard him swear at the ground control. Glad I installed chatterer also glad I didn't waste weight on the ladders. Kerbals must be highly compressible mushrooms!

Manned mission ascents on venus involved, SAS set to radial out, gridfins retracted, set balloon inflation to 100%, drop landing stage and speed off into the sky. Final peak ascent speed 192.5m/s at 12-15km. Crossed 50km at 150m/s and dropping rapidly. oscillated at 0.80-0.63atm ~55-56km. Set mechjeb for ascent 350km -180deg Inclination (because 0=180deg on Venus for no apparent reason), Ascent path numbers [60km, 100m/s, 250km, 1deg, 35%] Let go of balloon, fire engines, active autopilot. Orbit 350x349km with 1600-1800m/s maneuver fuel, meet up with transit bus at 300km orbit.

Off equator I had the bus maneuver a bit for plane changes. In those cases I had left it in a higher 500km orbit and it performed most of the plane maneuvers. Venus Rotates so slow that I didn't ever spend more than 500m/s to get co-planar even considering the lack of control over launch window.

Only needed 100-300m/s to compensate for any bad timing in the Hohmann transfers. That said I’m pretty sloppy with rendezvous maneuvers.

Really want RP-0 1.2.2 now, need to try this again. (Am i a masochist?)

 

Edited by Bornholio
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  • 4 months later...
On 29.07.2017 at 8:37 PM, Bornholio said:

Hooligan Labs. Make sure you change the value appropriate to real buoyancy.

I plan to repeat this in a while with a full RO/RP-0 install.

I tried with kerballoons, it worked after changing config a little. Hooligan labs seems more interresting! 
"change the value appropriate to real buoyancy" - what numbers do you suggest?

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1 hour ago, Liberty said:

I tried with kerballoons, it worked after changing config a little. Hooligan labs seems more interresting! 
"change the value appropriate to real buoyancy" - what numbers do you suggest?

Each buoyancy part has a part.cfg tag "envelopeVolumeScale = "  if you want realistic lift the value needs to be 1.  By default there is one part in the pack that is already. The "Deployable Envelope "Cirrus" - Real Lift"

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