Project Long Duration Deep Space Vessel

[Sky Captain]

This looks great; I'm really excited to fly it. I've been looking for a tasteful, realistic interplanetary vessel like this for a long time.

Thanks

Do you have any plans for textures (AMSO-style metal, thermal blankets, etc) on the larger sections, or are you just sticking with flat shading?

Currently I plan to release it like it is and later when I have made some better looking textures, animations, mesh improvements upload an update.

---------- Post added 09-18-10 at 12:28 AM ---------- Previous post was 09-17-10 at 12:41 AM ----------

Here it is - LDDSV with all hardware docked ready to start it's few day climb out of Earth gravity wel.








However it seems I have encountered an unexpected problem. When I have all the stuff docked RCS becomes nearly unresponsive, I assume because of all that extra mass that's far from LDDSV's centre of mass. Tomorrow I will try to make a "ghost" vessel with very strong RCS that would be docked to invisible docking port on LDDSV and to be used to quickly point the LDDSV in desired direction. LDSV own RCS would be then used to fine tune the direction.

 

[n72.75]

How much does the PMI change when the landers are docked. It doesn't look as if it should be enough to cause the RCS thrusters to become ineffective. Couldn't you just have two RCS modes: high and low, or something like that?

 

[Sky Captain]

That is behind my idea to create a ghost vessel with very strong RCS to have 2 RCS modes one strong and one weak. I think there is problem somewhere in how spacecraft3 module implements the RCS function because landers and hab's are ~5 % of overall fueled LDDSV mass so in theory there shouldn't be noticable difference with or without docked landers and stuff.

---------- Post added at 11:46 AM ---------- Previous post was at 12:43 AM ----------

I looked up spacecraft3 documentation and it says the RCS thrust is applied 1 m from rotational axis. I think that is where the problem lies and why I need so owerpowered RCS to be able to turn the vessel in reasonable amount of time. Only 1 m from rotational axis gives very short "lever arm" (I don't know how it's properly called in english) so it's very difficult to turn the vessel this large and with heavy payload docked ~100 m from rotational axis. If RCS were modeled to apply force few hundred meters away from center of rotation it would recquire relatively little thrust to rotate the vessel even with stuff docked to it.

 

[Sky Captain]

I managed to get two mode RCS to work more or less satisfactory. A invisible "ghost" vessel is docked near the centre of LDDSV and is given very strong RCS to quickly point the ship in desired attitude. LDDSV has weak RCS that you can really feel working only when at time acceleration. It has advantage that you can still use RCS when at high (1000 - 10 000) time acceleration which is useful to maintain correct attitude during long burns.

---------- Post added 09-20-10 at 01:16 AM ---------- Previous post was 09-19-10 at 08:08 PM ----------

I made it to Saturn in just 220 days!!!

Starting the climb out of Earth gravity well


To make ejection burn easier I established ~130 000 km high parking orbit.


Approaching Saturn


Orbit insertion burn finished.







I spent ~90 % of my trip under thrust. Outbound leg is easy - you just set course in IMFD and maintain correct attidude while thrusting. Tricky part is to determine when to start deaccelerating so you don't overshoot or deaccelerate too early. In this part of trip IMFD map program and Orbit MFD is the most useful. Deacceleration took about 2.5 months.

 

[docabn]

awsome looking ship :thumbup: (too busy to fly it seriously at the moment anyway) so it gives me something to look forward to at the end of this semester. Think I'll take an entire weekend and fly to triton or something.

 

[Sky Captain]

I just uploaded v1.0 on Orbithangar.

 

[Sky Captain]

I got an idea to break down LDDSV in components and make it buildable in LEO like a space station. And to transport all the pieces to LEO in reasonable number of flights we will need a large rocket.

So here it is







Recoverable booster modules seperating





Delivering The to orbit
:hail:


:hail:

 

[Izack]

That thing is large! It looks like something Doctor Robotnik would need. :lol:

 

[Stevodoran]

That thing is large! It looks like something Doctor Robotnik would need. :lol:

you always have to be careful when launching the probe even thought it can revive itself:hail::hail:

 

[Sky Captain]

That thing is large! It looks like something Doctor Robotnik would need. :lol:

Hehe, It can launch payload about twice as heavy as Nexus max LEO payload. Such large payload capacity is needed to launch LDDSV's nuclear reactors which are 2100 t apiece and LH2 propellant. I suppose it would be possible to break reaktors down into smaller parts launchable on Nova class rocket but then it would be ~20 flights alone just to put reactors in orbit and around 70 flights to launch all other hardwere and propellant which would make construction mission difficult to manage in Orbiter.

 

[jedidia]

not to mention that assembling nuclear reactors on Orbit would be a somewhat doubtfull task... radiation shielded Spacesuits, anyone?

 

[T.Neo]

I dunno... I think it may be possible to assemble some sort of compound reactor (i.e. a set of reactors), or even a reactor with multiple fission cores and shielding segments, but a linked cooling and operating structure.

Nuclear reactors are also (AFAIK) only severely radioactive if they've been operated before (or are currently operating, obviously). If the radioactivity of the uranium or plutonium inside is managable, it could be quite easy to assemble.

Obviously though, 50+ flights to assemble a reactor would be impractical to do in Orbiter.

I can't help thinking that parts of LDSV are heavy for what they do though, particularly the truss and the propellant tanks. Though the reactors seem quite light for their power output (if I have done my math correctly, that would be a very interesting alpha of 0.074 kg/kW, the best achieved by an experimental nuclear reactor is 0.493 kg/kW). I can't really tell how large the actual habitation modules are from the image, but they could be quite heavy. Then again, radiation shielding adds up...

 

[Sky Captain]

My assumption for reactor power to mass was 10 kw/kg (electrical) and 15 kw/kg thermal and efficiency of converting heat to electricity 66.7%. I think the best power to mass ratio in a nuclear reactor was achiewed in Tory 2C nuclear ramjet prototype which ran for 5 minutes at 513 MW. I couldn't find the mass of the reactor, but according to this source
http://www.designation-systems.net/dusrm/app4/slam.html
Pluto cruise missile would have mass of 27.5 tons. Assuming half of that goes to reactor it turns out a Pluto missile would have reactor with power to mass of ~40 kw/kg. Granted, the Pluto did not have radiation shielding and heat to electricity conversion machinery so in a reactor that has all those features you couldn't get power to mass that high.

Habitation modules have total volume of 20 000 m3 and with average density of ~140 kg/m3 hab comes out at 2800 t. Truss structure has mass ~400 t (scaled from paper about Discovery II).
Propelant tanks have dry mass 1800 t and they house 43700 t of LH2