Best way to build and fly a large interstellar mission?

[MedwedianPresident]

When I will return home in 2 weeks, I want to make a mission video and publish it on YouTube.

I've heard that there is a mod called Kerbal Galaxy or something that combines all planet packs into various star systems, all orbiting a black hole. I imagine that this allows for the planning, building and execution of more futuristic missions, including the replication of various missions depicted in Hard-SF, STL interstellar travel-themed novels such as The Songs of Distant Earth or Murasaki.

Now, I want to send 100 kerbals, let's say, to Nix, a planet with slightly higher gravity and the same atmospheric pressure as Kerbin, which orbits the Abbadon star. The kerbals will set up a colony, so they probably won't return, yes, this is an one-way mission.

It is self-explanatory that the ship will have to be assembled in orbit. Everything else is open.

Now, what is the ideal type of ship which I could use in such an interstellar mission. This is supposed to be realistic, so no Alcubierre drives, Warp drives or Stargates. Should I use ion engines, the Orion drive (Yep, there's a mod for that), nuclear engines or convertional rockets?

1. Propulsion

Ion engines: In conjunction with a nuclear reactor, they will probably work, especially for the finer maneuvers - in interstellar space, the "finer maneuvers" may still require hundreds of meters of DV.

Orion/Medusa/other big nukes: They have got lots of power, but the problem is that, since I want to keep it realistic, I don't want to irradiate Kerbin after departing (Unless I will decide that my storyline is that Kerbin is dying after a nuclear war and the colony consists of a few survivors, of course then there is no more point in not using an Orion drive in LKO.), this means that I will probably need another method of acceleration for leaving Kerbin orbit (normal nukes, chemical rockets or ion engines).

Convertional nuclear engines: Can maybe used for larger maneuvers or for acceleration.

Chemical/Monoprop rockets: Giant rockets consisting of thousands of liters of liquid fuel and tons of SRB's will of course be the way of launching the whole stuff into space. Remember, the ship will be so big that one "small" module will have to be launched with a rocket even bigger than the N1. Chemical rockets can be used for orbital maneuvers, chemical rockets or large monopropellant engines will be used to turn the ship.

Solar sails: I imagine solar sails can be used for the initial acceleration phase and for helping with the deceleration when arriving in the Abbadon system. After that, they'll probably be just dead weight, so they will likely be dumped. I say solar sails and not single solar sail because i will need lots of them to actually reach something.

Gravity assists: The black hole...

Aerobraking/Aerocapture: Will probably not work because the ship is too big and will likely break apart during reentry, even with thousands of struts. If I will use it, then it will probably be in the final braking phase since aerobraking at interstellar speeds is not very healthy.

2. Mission profile

How should I combine the propulsion methods to create an effective mission profile? I could use a generation ship and a complicated route which takes up several thousands of years, but I could also accelerate to near-lightspeed and wait for a couple of months (which will turn into minutes for me because of timewarp, but still be extremely boring for the kerbals), and of course any profiles inbetween are allowed.

I imagine that the solar sails will only be used as emergency propulsion if the main engines fail.

A mission profile I have thought up of:

The ship "MSS Endeavour" will assembled in orbit from large modules which will be launched using giant rockets.

The ship has a length of more than 1000 meters. The rear part contains of a large propulsion module which takes up the biggest part of the ship and consists of large stacks of orion engines as well as the nuke containers. Several acceleration stages consisting of massive SRB stacks as well as liquid fuel tanks are placed behind the nuclear stage that will be used for maneuvering within the Kerbol system. The propulsion module also contains a nuclear reactor that will be used in deep space when solar energy is unavaliable. The main propulsion module is separated from the middle part by a large shield that will protect the rest of the ship from irradiation. The middle module contains lots of ion engines for inner-system maneuvers and course corrections or as an emergency propulsion system. It also contains massive xenon tanks. The front part of the middle part contains life support systems, solar panels as well as docks and hangars for shuttles and landing craft. The front part of the ship is dedicated to habitats, laboratories, workshops, the bridge of the ship and farming and hydroponics modules. The ship rotates constantly to create an artificial gravity effect. The front part also includes solar sails which can be used if all means of propulsion will fail or to assist the convertional propulsion systems if a partial engine failure occurs.

After being assembled and fueled, the ship will receive its crew and passengers. The spaceplanes that will be used to crew the MSS Endeavour will also be used for landing on Nix. After the final system checks are completed, the ship will be brought onto a higher orbit using the ion engines. Then, the first booster stage will ignite that will eject the MSS Endeavour out of Kerbin's SOI. The second booster stage will be used to lower the periapsis of the MSS Endeavour so that it will pass only thousands of kilometers above Kerbol's surface, where the third booster stage is ignited which will push the apoapsis above Kerbol's SOI. Maybe a flyby of some planet (maybe even Kerbin?) is made before the Orion drives are ignited. They will fire in turns so that acceleration will be constant, the crew maybe will be placed in hibernation if this is not possible since having quickly variable gravity is not very comfortable. After the ship is placed onto a trajectory towards the Abbadon system, the orion drive is deactivated and the crew can return to the habitat, which rotates to cause 1 g. Several years of flight time will pass until the MSS Endeavour approaches the Abbadon system. The orion drives are used for deceleration, and the periapsis around Abbadon is set very low to perform the opposite procedure as when leaving the Kerbol system. The main propulsion module is jettisoned to prevent irradiation of the system, it will plunge into Abbadon. The ship is placed on a trajectory which uses several gravity assists to further decelerate it until the Nix system is reached. The ion engines are used for orbital capture, maybe a risky aerobrake in which the irradiation protection shield is used as a heatshield, is used. After entering a low equatorial orbit, the depleted ion propulsion module is jettisoned. A probe is sent to decide whether Nix is habitable enough for the instant creation of a colony or if subterranean facilities or habitation domes need to be built first. If habitation domes or underground bases will really be needed to be built, the MSS Endeavour sends a signal to Kerbin and remains a space station in Nix orbit while the surface is explored by research teams and the crew of the Endeavour hopes for a second ship with supplies to arrive. If the planet is habitable and the air is breathable, the shuttles are sent down which contain various supplies to build primitive houses. The MSS Endeavour has got oxygen and supplies for up to 50 years after arriving in the Nix system. The population will be transferred to the surface within several years, and all empty modules are dismantled and used as construction materials for the surface colony. The MSS Endeavour is gradually dismantled while the population of the colony increases. If the foundation of a surface colony is impossible, the crew of the Endeavour will have to wait for the supply ship arriving from Kerbin and eventually exploit the planets of the Abbadon system to gain Oxygen.

The mission can be aborted before reaching interstellar speeds and leaving Kerbol's SOI. The booster stages and the orion and ion propulsion systems are used to neutralize the velocity of the MSS Endeavour and bring it back to Kerbin.

Storyline elements for an AAR:

- Various factions on the station, maybe even resulting in the separation of the MSS Endeavour into two or more parts upon entering Nix orbit. Formation of various countries on Nix.

- Population explosion. Something went wrong and the kerbals started reproducing while still in interstellar space. The Captain calculates that there is not enough oxygen for everybody to survive until arriving in the Abbadon system. May involve mass executions.

- A self-destruct switch which allows the Captain to terminate the mission if a rebellion starts.

- Irreparable engine damage. The MSS Endeavour is stranded on a trajectory that leads into deep space, into the wrong star system or on a plunge into the black hole.

- A war breaks out on Kerbin while the ship is in flight.

- Life on Nix.

- A virus infects the population.

- Aggresive, intelligent life in the Abbadon system. The crew and passengers of the MSS Endeavour must struggle to find a safe place in the system without being destroyed by a massive array of defense sattelites.

What do you think of my ideas? How would YOU design the mission?

[Richy teh space man]

Kind of reminds me of the old Windows game Outpost, where one spaceship with about 200 colonists leaves Earth before it is destroyed to start a new colony in another solar system. It allows the player to build up a fully fledged colony from starting with just a few landing ships.

It's an idea for a series if you also added extra planetary launchpads to build stuff in situ once you arrive. There's also cryogenic mods iirc, but not sure how up to date they are.

[magnemoe]

Well the medusa can not be used in atmosphere anyway.

I would launch it with minimum nukes and then resuply in orbit as its far easier to launch a 200 ton magazine than launching it with the medusa.

The medusa has the benefit of more equal trust and pulls making it easier to assemble stuff on it.

Pretty much perfect for an interstellar mission where the distance is not light year,

If you don't want to us it in LKO you could use an tug to push you at least halfway to Mun before starting it.

9 LV-N behind an MK3 tank, this docked on back of ship and push.

You use chemical engines as secondary engines on the mothership.

This is my medusa for interplanetary work. its delivering an large mining base to Gilly. 4 radial engines as secondary engines.

For your setup I would made the ship mode modular. Just fuel and perhaps an small cocpit/ crew quarter on ship, you might use fuel tanks as shielding.

Then dock everything behind.

I would probably used MK3 cabins who later could be landed as the main crew facility on base. You want to bring an mining setup and an SSTO spaceplane.

Extraplanetary launchpad would be nice but pretty OP.

[Fluburtur]

This all sounds nice but you would need a supercalculator for a ship of that size.

I wish you good luck on this, I would love to see that kind of thing.

[magnemoe]

This all sounds nice but you would need a supercalculator for a ship of that size.

I wish you good luck on this, I would love to see that kind of thing.

Main issue here is if you bring with you lots of stuff like the SSTO spaceplane.

Extraplanetary launchpad will let you build stuff at the new location and would reduce part count a lot.

My ship would not require so many more parts with 8 Mk3 crew cabins.

[eataTREE]

The mod KSP Interstellar Extended gives you a few more propulsion options that you might find attractive. It has a few drawbacks -- it introduces a resource-based "Waste Heat" system that is separate from the native thermal model, it has a huge number of parts, which might be a problem if you are low on RAM, and how to make things work isn't always immediately apparent. However, it still has a reasonable implementation of nuclear fusion-based reactors and spaceship drives which can go the (interstellar) distance. Best choices are either the VISTA inertial confinement fusion drive or a fusion reactor with magnetic nozzle; either way can yield megameters of delta-V on a properly designed craft. Recent versions of the mod let you continue to thrust while the ship is unfocused, which is pretty convenient -- getting up near lightspeed requires that you burn for weeks and months rather than minutes and hours.

I would also suggest looking at the Deep Freeze Continued mod. Frozen kerbals don't eat, drink, or breathe, which can cut down your payload mass a LOT on a fifty-year mission.

Part count doesn't necessarily need to be an issue if you design your craft well. Whether it's crew cabins, structural members, or fuel tanks, use a few REALLY BIG parts rather than many little ones. Avoid long, spindly designs that require a multitude of struts to hold together. A design which puts the engines first and tows the payload/crew section along behind can be less susceptible to wobble and flex than a more traditional rocket design.

Looking forward to seeing your screenshots/results.

[ThePULSAR]

always press F5

[magnemoe]

How long travel distance are we talking about here? compared to the distance to Jool?

25 km/s will take you to Jool in around 60 days if Jool is right outside Kerbin from Sun.

Interstellar position does not matter much but you would use 100 if Jool is pretty opposite.

So if distance is say 20 times the distance to Jool you will use 600 days on the trip or less than 3 years and far shorter than an Hohmann transfer to Eeloo, more like an Hohmann to Jool

[cantab]

Galactic Neighbourhood is the one that aims to support loads of other planet packs, not Kerbal Galaxy. Though either is good depending on what you want to do.

I believe the nuclear pulse drives will completely trounce anything else for performance. Ion engines of some description (probably modded) for fine propulsion sounds like a good idea though. The main drawback to using ion engines for main propulsion is the long burns. It's not so bad when you want 5 or 10 km/s of delta-V, but if you've got 50 or 100 km/s and you're accelerating at 1 m/s/s that's hours and hours of continuous thrusting to use it all up. That said I had some success with an asparagus-staged nuclear-electric ship using Near Future parts, many versions ago; it packed 50 km/s or so with a 65 ton payload and maintained around 4-5 m/s/s acceleration. Of course it was pretty large.

You'll probably want a mod to increase timewarp limits, unless you fancy leaving the game running and watching a movie or two while your ship cruises between the stars.

[Whirligig Girl]

Use a custom-built truss segment adapter and launch the Orion into space (but not orbit) using SRBs. That way you don't worry about irradiating Kerbin.

One thing you might need to worry about is that KSP has a maximum time limit (I think it's as low as 200-something years, I don't remember), after which any on-rails motion will break. Planets will not move, and neither will your ship in timewarp. I think you can get around this by using HyperEdit to start out at the negative time so that you double the time you have until time stops. The best way around this is just to not have ships going for hundreds of years, which seems to be your plan anyway.

Edited November 5, 2015 by GregroxMun

[SciMan]

Currently I use warp drives and other propulsion methods from the KSP Interstellar Extended mod, even tho I'm only going out to Jool (I hate long timewarps of doing not much, but I only run single missions at a time).

Since you say you don't want to use warp drives, if you're going to use KSPI-E I'd suggest you use a magnetic nozzle powered by a fusion reactor running off the Deuterium-Lithium fuel cycle.

In my experience this is the quickest way to get around without a warp drive, and it doesn't tear your ship apart like a Orion or Medusa drive can.

With the size of the ships you're going to be needing, you should really get Kerbal Joint Reinforcement (KJR) because huge ships will wobble without it no matter how many struts you use.

Let's be clear about one thing.

This is something that's probably going to take a lot of tech from VERY late in whatever tech tree you're using.

If you're converting the science to more funds (and you should be with how expensive these things get), or just as a scorecard, that's fine.

This isn't something you do for the purpose of scientific returns. This is an end-game continuing goal.

[Umlüx]

@ship size: best thing would be to use the welding mod.

build the base structure of the ship, the structural skeleton and some tanks, then weld it. voila - a big and rigid single part to attach everything on, like habs, propulstion, electronics etc...