Duna Semi-Direct (long-term mission to Duna)

[MaverickSawyer]

Greetings. I am beginning to make plans and preperations for a three-man mission to Duna.

A brief overview of the planned mission:

Launch of Nuclear-electric Transfer Stage and Habitat (NTSH). Enters parking orbit at 300 km and less than 1 degree inclination (mechjeb controlled ascent). Decouple the one-man pod, pitch up 90 degrees, and engage the twin Sunbeam lasers to clear off the remains of the decoupler (if I can't find a decoupler that completely dissapears). Crew deorbits for a precision landing at the KSC.

Launch of Crew aboard the Duna Excursion Module (DEM). Meet up with NTSH and dock. Transfer crew to Habitat (crewtank).

Kerbin Departure, Mid Course Corrections (MCCs).

Duna insertion burn. Orbital adjustments.

Crew transfers to DEM, undocks, and descends to the surface. Crew spends extended surface stay exploring the area. (Rover still under consideration, as it may require a third launch)

Crew leaves Descent stage behind, ascends to meet the NTSH, docks, transfers, and ejects the ascent stage of the DEM.

Duna Departure, MCCs.

Kerbin insertion burn, orbital adjustments.

Launch of Crew Return Capsule (CRC). CRC meets and docks with NTSH, transfers crews (new crew is maintenace crew), heros return to Kerbin.

New DEM launches with new crew, and cycle begins again.

I have a few sketches laying out the basic ship designs, and I will scan them soon and post them here. Mission updates will be added as things progress.

[Nibb31]

That is a sound mission design. The problem is warping on an interplanetary transfer is not supported by any of the current docking mods. Chances are that the ship will break up. This is why a few of us have gone fore Duna Orbit Rendezvous (DOR) instead of Kerbin Orbit Rendezvous (KOR) for our mission architectures.

http://kerbalspaceprogram.com/forum/showthread.php/22571-Two-Vessel-Mission-into-Duna-and-back%21

[Commander Zoom]

This thread is highly relevant to my interests, as I'm considering a similar mission profile (though, as Nibb31 notes, the rendezvous will probably occur at Duna rather than Kerbin, due to certain limitations of the current engine and/or add-ons). My own rough plan involves a crew transfer vehicle (including hab) which travels to Duna orbit and back to Kerbin, never landing until the capsule splashes down, and an uncrewed lander, which only needs to make a one-way trip. I'm having to start from scratch with the lander, beginning with an ascent stage that can reach orbit from Duna (or Eve or Laythe - my hope is to use the same design for missions to all the planets), then a descent stage added on to that, then a transfer stage, and finally a booster that can get all of that off the pad. This would be a lot easier with orbital construction.

I'll also note that I was slightly confused when you mentioned a rover in addition to your DEM, but that's probably because I'm so impressed by (and habitually now think of) BobCat's DEMV - a rover, designed for Duna (hence the acronym) and other worlds.

Edited October 4, 2012 by Commander Zoom

[MaverickSawyer]

Good point about the warp issue. Is this the Space Cthulhu? (Probably spelled it wrong, but WTH.) If that's the case, I'll just undock after TDI burn, and redock for MCCs and Duna insertion burn.

Also, I had some further ideas about expanding upon this for use in the Joolian system and using a node to hold minilanders for use in inspecting possible LZs for a manned lander.

EDIT fixed typo. Thanks, Jeb KerBoom.

Edited October 4, 2012 by MaverickSawyer

[Jeb KerBoom]

"Cthulu"

It's actually spelled Cthulhu

Disclaimer: I am not attempting to derail this thread, I am fixing a minor error.

[MaverickSawyer]

Thanks. I'll fix it.

[nhnifong]

That is a sound mission design. The problem is warping on an interplanetary transfer is not supported by any of the current docking mods. Chances are that the ship will break up. This is why a few of us have gone fore Duna Orbit Rendezvous (DOR) instead of Kerbin Orbit Rendezvous (KOR) for our mission architectures.

http://kerbalspaceprogram.com/forum/showthread.php/22571-Two-Vessel-Mission-into-Duna-and-back%21

Warping at any speed works just fine with erkle's clamp. Just don't pass through two SIO transitions without going back to 1x. In general going back to 1x every 10 weeks or so of in-game time is a sound way to avoid explosions.

[MaverickSawyer]

Excellent news, nhnifong. I was planning on running a fairly realistic mission, with routine EVAs for maintenance and relieving cabin fever, and MCCs to refine my course over the transit in both directions. These would probably be enough to be Cthulhu-repellant.

[nhnifong]

Excellent news, nhnifong. I was planning on running a fairly realistic mission, with routine EVAs for maintenance and relieving cabin fever, and MCCs to refine my course over the transit in both directions. These would probably be enough to be Cthulhu-repellant.

Haha, I will from now on think of warp-related position bugs as "cabin fever"

[MaverickSawyer]

Ok, this video was part of my inspiration of how to perform this mission...

[MaverickSawyer]

Ok, update time.

As I mowed the lawn today, I put some more thought into my mission plan. Updates to the mission are as follows:

-Adding a Crew Tank to the Descent Stage of the DEM. This will allow a colony/research base to be established in less time, without needing to deploy missions just to place habs on the surface.

-Adding 4 MechJeb-controlled probes to the composite craft, likely by radially attaching them to the Duna Excursion Module. All four will be capable of making a completly propulsive landing on the surface of Duna, but will also pack a parachute to conserve fuel slightly. These will be used to scout out possible landing sites for the DEM.

-Adding a possible fourth crew member to make possible a 2-2 split: two will go down to the surface in the DEM, and two will remain aboard the Nuclear-electric Transfer Stage and Habitat. This may perform a flyby of Ike on the way in, and drop off a pair of probes in the vicinity of said body for exploring possible LZs.

-Making use of Aerobraking to lower Apoapsis. I do NOT intend to utilize Aerocapture, especially with a composite craft. Later mission to establish a research base may make use of direct entry or aerocapture, but those are beyond the scope of this thread.

-If Ion RCS exist, using these will allow for much more reusability of the NTSH. Currently, the RCS fuel is the limiting factor for the reuse of the NTSH. As such, if RCS are needed for vernier manuevers, they will be executed with the DEM RCS.

-If is is within my mass budget, I will include landing gear on the NTSH for operations on Ike. Ladders will NOT be included. Any surface operations will be aborted at 25% RCS fuel remaining.

-Initial thrust to kick out of the Kerbin SOI will be provided by the DEM launcher's upper stage. Why waste fuel?

That's it for the moment, and I'll be starting design tomorrow.

[MaverickSawyer]

OK, primary construction completed. Following items are of note:

-Mass budget did allow for landing gear on the NTSH for Ike missions. Now need to figure out how to get a fourth crew member aboard the NTSH. Maybe I can leave the crew pod from the launch on orbit, and EVA the pilot across... Must put more thought into this.

-Miniprobes are proving difficult. I am trying to use Nova Silisko's Probe Kit for this, but the fuel tanks just don't want to attach to a radial decoupler. If you have any ideas, I am open to suggestions.

-Added a pair of solar panels to the craft. Combined with the RTGs, I should be able to trickle charge the batteries before I depart. I'll power up the nuclear reactor to extend the burn time, but for no other reason.

Otherwise, nothing of interest. Cheers!

[MaverickSawyer]

So, courtesy of a friendly forum member, I have a launch window, but it's a ways off. This project is now in hibernation until the launch window approaches, and I will transfer my focus to the Mun and Minmus. Some of these missions will be in support of the Duna Semi-Direct mission, and some will be in support of future missions. Cheers!

[0jam3290]

Wow, that has some amazing planning to it. Reminds me of Constellation.