Emulating Omuamua Alien Spaceship with Kerbal

Omuamua is an asteroid discovered by scientist in the last year which had an strange behaviour as it accelerated during its close orbit on the sun doing a gravitational assist. It hit the news so many times that I guess everyone knows about it.

There’s a lot of people still believing this has to be an alien spaceship or probe, because, what else? Scientist have debunked each one of the alien theories one by one and seems pretty clear that it is just a rock, and we just got lucky.

But let’s go crazy, because it’s fun! Repeat with me: it’s aliens. It has to be aliens and there’s no other option!

So to prove those scientist wrong, let’s build our own version of Omuamua in Kerbal Space Program. I have been posting some entries lately about this game, it’s a game and a space exploration simulator at the same time. It contains a Solar System scaled down, with its own planets and so, but it resembles a lot to our own.

I’m going to make use of different mods to emulate futuristic technologies, and also I’m not going to fly most of them, as launching thousands of tons is really hard and time consuming. Instead I’m going to defer to the numbers reported by Kerbal Engineer Redux. Also, I’ll oversimplify the maths involved because it should be enough for our purposes.

Mission definition

We want a spaceship or probe that is capable of leaving our Solar System, reach a near star and slow down to be able to do a gravitational assist. It has to be done in a time-frame that is meaningful for our species.

The nearest stars are about 1.5 light-years away. This number will be our target. We want to get there in 200 years or less; mainly because in that time another better technology could overtake the craft, and anyone living in here will probably no longer remember how to communicate with it.

The required speed to reach that star in time we can just do:

v = c / 200 * 1.5 = 2248 km/s

In KSP terms, this means we need a DeltaV of 2248000m/s to get that velocity. But then we need to slow down! so we need the same DeltaV again before reaching the star. This, of course assumes that the destination star moves at the same speed and direction over the space as the Sun.

So the desired DeltaV we’re looking for is 4497000m/s, but I’ll round it to 4.5 Million meters per second. Also this does not take into account the time required for accelerating or deccelerating; in the ships I’ll be building they will be accelerating for years, so the end result will be higher than 200 years.

So, the mission in short is: Build a KSP probe that has 4.5 million m/s DeltaV. I don’t care on launching.

First try with almost no mods

We will need something to communicate, so let’s add a big antenna. And obviously huge batteries and solar panels to get the energy…. Wait a second! There’s almost no sunlight when we’re outside of the Solar System! so I’ll need to add a nuclear reactor instead. Sadly the NUK is not enough to power anything, so I’ll go with solar panels for now. Add reaction wheels, and a huge bunch of Xenon tanks, and the Ion Thruster. Ready to go!

This is the first and last spacecraft in this post that will make any sense.

We got around 36km/s of DeltaV! not bad at all. But this is only a 0.8% of the speed required to get there on time. Let’s go the Kerbal way and BUILD BIGGER

Let me now use the Rescale Everything Mod to scale those silly Xenon tanks up, add some staging, and change the engine design so we don’t lose the engines on staging.

I know. It looks silly. It won’t work. Whatever.

We reached now 163km/s! This will take around 7-8 months of acceleration to deplete the Xenon tanks. Looks like a lot, but this is only 3.6% of the DeltaV required. Still far from there.

Adding more stages and bigger tanks will be ridiculous here and it will give us around 40km/s extra. So no point on even trying it. This beast is already 3 thousand tons and it would need to be assembled in orbit and fuelled in orbit, requiring around 8 trips at least and I bet that these launches would look insanely huge and expensive.

Near Future Propulsion

So this was not enough. Clearly we need a better ISP in our engines so I’ll install Nertea Near Future mods. In fairness, the Ion Thruster in stock has only 4200 in ISP, which is what we have ready now, but in the upcoming years this may change drastically. Aliens have better technology for sure!

Near Future Propulsion adds an Ion engine with an ISP of 19200s. Before any of you scream “that’s cheating!”, please let me refer you to this Wikipedia page: https://en.wikipedia.org/wiki/Dual-Stage_4-Grid

There you can see this engine is capable of an ISP of 19300s. It is not ready yet. Those two ISP numbers are pretty close, so from here comes the inspiration for the Jewel-4 from Near Future Propulsion.

OK, let’s build now! With nuclear reactor, please!

I really doubt that reactor can hold charge for 6 months

Now I got 229km/s! We’re getting there… or are we? This is still just 5.1%. But remember in Kerbal we can BUILD BIGGER!

Wonder what the governments will say when they the quote for this

560km/s, still 12.4% of our target. Wonder if I can add more fuel without exceeding the hangar…

I bet this one does not fit over the hangar doors

I got 897km/s, awesome! Probably the most ridiculous DeltaV reported in Kerbal that most players has seen, ever. 19.9% of our target. There is 36,000 tons on Xenon fuel to deplete. How much it takes? 12 years for the four tiny engines that are hidden behind the tanks.

The first stage is composed of 6 tanks of 20 meters each, 39,000 tons of weight.

Interstellar Extended

These engines above are so lame… real Aliens have much MUCH better technology. They would go all-in nuclear for sure!

We have available in Kerbal one Mod called KSP Interstellar Extended which includes all kind of crazy nuclear and antimatter designs that never leaved the paper. If you want to explore other stars in Kerbal, this is the mod to go! (spoiler alert: there aren’t any)

Let’s get on and start building. What do we need? A working fusion reactor, a converter to get that energy back to electricity and a VASIMIR-500. Also a pair of huge hydrogen tanks:

At least this one fits over the door

VASIMIR-500 has a maximum ISP of 29560 in the game, given that is fed with liquid hydrogen and the thrust is 5% or lower. One of the key features of a VASIMIR (they’re real) is that better trust to weight ratios can be reached at expenses of lowering the ISP.

But, this particular engine is way far off from reality. Usually they have an ISP of 5000s while using Xenon. Using Hydrogen, they are going to be much more efficient, but I cannot find any resource proposing more than 10000s of ISP. So without any paper or research giving support for this, I would say that this one is pretty cheaty and purely fictional.

Anyway, easily I could get a DeltaV of 388km/s, and should be possible to increase it scaling up. The problem though is, Hydrogen is really low density and those huge tanks only hold 67 tons of hydrogen together. So the problem now is going to be the required space to fit the enormous tanks.

Notice the ridiculous size compared to the buildings

This setup only gave 825km/s, which is roughly the same as with the Grid Thruster from Nertea’s mod despite having almost double ISP (29650s). This contains 17,000 tons of hydrogen.

There are two reasons on why it failed short. First, Hydrogen is so light that even for the biggest tanks, a big part of the weight is still the container. The second reason is there is no staging, so the tanks cannot be dumped as it goes. It is really difficult to design stages when a single stage already takes the whole VAB.

We could build some stages and use Helium instead. Being slightly denser, it will pack more, will be better for fuel mass to container ratio and will make me able to build some stages.

If it contains four helium balloons, will it fly?

Now this thing has even less DeltaV. The ISP lowered to 20977s due to the usage of helium instead.

As we can see, we’re going backwards. This is even worse than ever. This interstellar mod, doesn’t have anything really good?

Well, it has the so called Magnetic nozzle. Something really huge that takes ionized hydrogen and magnetically pushes that to a 26% of the speed of light. If this is not science fiction, please let me know what classifies.

Luckily, this engine allows thrust while warping.
Otherwise it would take years of gameplay to deplete the tanks.

This is only using 113 tons of hydrogen and I got an astounding 8067km/s of deltaV. The Trust to Weight ratio is zero. On the other hand, this is 179% of what we needed, so almost doubles the needed. Good, right?

Well, no. Despite I had to add a Stellarator Fusion Reactor of 40 tons generating 65 Megawatts of energy, even if that is real someday (I doubt it), I don’t think that is enough to accelerate Hydrogen ions to 26% of the speed of light. Or if it is, the magnetic forces could rip the spacecraft apart easily.

Orion project

Back to reality. There was something called Orion project, the idea is simple and it was proven to be working at a really small scale: shot nuclear bombs behind the vehicle and use pistons to receive the blast and accelerate by “surfing” on top of those.

Resultado de imagen de orion project
Seems a really good idea, blast those nuclear weapons near the earth atmosphere.
What could go wrong?

There’s a Kerbal mod for this, simply called “Project Orion” Nuclear pulse engine. It worked well, but I updated recently my KSP and I’m not going to bother with it for now. They’re really powerful and the ISP is off charts.

The wikipedia article about Project Orion is enlightening. Ships with it could reach Alpha Centauri in 44 years. And this technology is doable currently. Amazing!

But well, no one wants to put 300,000 tons of atomic bombs into orbit and even with that, no one will agree to start those engines unless is really, really, far away.

But we’re talking about building Omuamua. Did we see any nuclear explosion? Scientist were confused because they didn’t see the typical jets from comets (gases), so we can assume there was no nuclear detonation for sure, as that would be alarmingly easy to be seen.

Solar sails

A few scientist proposed that Omuamua could be a Solar Sail, and that would explain the acceleration we saw. But even SETI researchers have laughed at that option. Why?

Well, a Solar sail has to be accelerated using lasers in order to get good speeds. This is called beam-powered propulsion and currently is the most probable technology that will be used to send probes to other stars in the future. This is also one of the “alien” explanations as well for the FRB phenomena.

Resultado de imagen de beam powered propulsion
I gave up trying this with the Interstellar Mod.
Here’s an artist concept on how it should look like when you get it working.

But this technology has a pitfall when you compare it to Omuamua. The so called asteroid was entering our Solar System around 25km/s (I don’t recall the correct number now). If it was a sail coming at more than 1% of the speed of light, how did it slow down? That’s simply not possible.

Also, scientists describe Omuamua as having a cigar-alike shape. Does this have a cigar-alike shape?

Resultado de imagen de solar sail
I ran out of funny jokes by now. If you have any, post them in the comments.

So it seems pretty clear that IS NOT a solar sail. So?


Omuamua is an alien spaceship and Kerbal Space Program is not powerful enough to emulate it. They came, saw our lame television programs and ran as fast as they could.

Why? Because I said at the beginning that there was no other option than aliens and I had to stick with it until the end.

Have fun playing Kerbal!

Kerbal – Surviving with USI Kolonization mod

Kerbal Space Program is an awesome game, with almost endless posibilities. Add a few mods to it and the things you can do just explodes. Fantastic!

Today I want to talk about Umbra Space Industries mod, also known as Kolonization.

When you become an “expert” on playing Kerbal, Kolonization adds a new challenge: Keeping your Kerbals alive, they need to eat and to rest. On the default configuration (the only one I’m going to talk about) the Kerbals become Tourists if they cannot eat or rest enough, rendering them useless.

The common problem with this mod when you start with it is the mechanics are quite complicated even for KSP standars. Even when you think you got it, you end with ships that weight so much that are almost impossible to launch, or after docking a few, the game slows down significantly; not because Kolonization but because Kerbal does not play well with so many parts. So the challenge here is keeping things small and simple at a start even when Kolonization mechanics seems to require so many parts.

Kolonization basics

While on flight, there are two buttons that USI Kolonization adds:

The top one is where we’ll focus, while flying it displays the current status of your kerbals of all your vessels (including other vessels in other bodies)

Here we can see already the requirements for our Kerbals: Supplies, EC, Habitation and Home. A short explanation of each one:

  • Supplies (sup): Food available in the vessel for sustaining the Kerbal. It is a new resource and we should add supplies tanks now on each manned vessel.
  • Battery (EC): Amount of electricity for your Kerbals, as they consume it too now. It does account only for the amounts consumed by the Kerbal and does not count generation on the calculation. For example, if you have a small battery but you’re generating a lot of electricity (solar panels) it will not be accounted here although the counter will remain stopped as if they weren’t consuming it.
  • Habitation (hab): The amount of space to live they have “remaininig”, as even if you add more space than enough, at some point the Kerbals need to go back to Kerbin. This value is incremented via new parts.
  • Home: The maximum amount of space to live they have. Also serves as a global counter to get back to home.

Tip: Don’t be fooled by the screenshot, as usually you’ll get only a few days of food and home unless you build something huge.

Food cycle

There are lots of cycles in Kolonization to manufacture different resources. But the most important one is the food cycle. Sending supplies for each trip is not feasible.

For starting, the best bet is using agriculture Agroponics to get some supplies. Send Fertilizer along with your supplies and one agriculture module like Nom-O-Matic 25000 to convert the fertilizer back into supplies. This should be enough food for a pair of Kerbals for several years:

This does not cover habitation

The way it works is, Kerbals will eat the supplies, they will poo the same weight in Mulch, this will be recombined with Fertilizer with the agroponics to get more supplies (Nom-O-Matic takes care of this)

The problem with agroponics is that we don’t get more supplies than we started with. As it depends on mulch, if food is not eaten, fertilizer will not be used to generate more supplies. It is a great setup for space and for most in ground colonies. But just remember to bring as many supplies as fertilizer.

There are proper agriculture cycles, requiring tons of water and either Minerals or Gypsum. These are inferior to agroponics, but it lets you produce supplies on ground even with no kerbals. So they are best for generating supplies in other bodies for later collection.

As for how many agriculture modules you need, usually even the small Nom-O-Matic 5000 will be enough for 1 Kerbal. The 25000 version depicted above should take care for 5 Kerbals, and the 25000-I for 10 Kerbals.

We can increase the efficiency of this by the use of recyclers. These lower the supply consumption of our Kerbals. Kerbals on average eat 0.45 units of supplies per hour, with basic recycling it can be 0.10u/h. This means 4 times more life for the same weight!

This makes recycling even more important than agriculture. Because fertilizer is weight that you have to add, the less your kerbals use will mean you’ll need a lot less weight for your launches for very long trips. Also, you’ll need less weight in agriculture modules, so it pays off in several ways.

RT-500 and RT-5000

The recyclers add a recycling efficiency for a certain amount of kerbals. If you have all your kerbals covered, adding more will not result in a better efficiency. If you have a good one that does not cover all, and several worse ones, the good one is used first and the bad ones afterwards until the demand is covered.

The most basic one, the RT-500, covers 1 Kerbal for 60% efficiency. This is a 2.5x boost. It is cheap and light, so adding a few is a great option.

The RT-5000 covers 3 Kerbals for 79% efficiency. 4.75x boost. Not so light in comparison, as it weigths 3.75 tons and the RT-500 only 0.1 tons. This means that you can cover a lot more Kerbals with the basic one. You have to pay the extra weigth for the added efficiency.

They work by usinc EC, so keep the numbers in mind. But the energy usage is low anyways.

There are better recycling efficiencies, the best one being the water purifier cycle in modules like the MKS Duna Kerbitat:

MKS Duna Kerbitat

The water purifier included in this module have a 88.5% efficiency for 4 kerbals. Other purifiers have even better values. This is a 8.7x boost or higher. These are really good, but only when landed and having water to mine (or mine Ore or Hydrates and convert them into water). In space, purifiers are useless as they use tons of water very quickly, so it is pointless to try to send them water regularly.

This module also includes habitation and a regular recycler for 4 kerbals at 77% efficiency (4.3x boost), making it excellent for starting colonies on ground of 8 kerbals. Just be sure to land in some place where you can obtain water. If you aren’t that lucky or in space, at least you can use its recycler.

The agroponics cycle has a conversion ratio of 1 to 11. For each ton of fertilizer you get up to 11 tons of supplies.


Stock command pods have one Kerbal-month per seat. There are lots of other options available as new parts to get a bunch of extra kerbal-months.

Kerbal-months are a measure of how many months (30 kerbin days) a single kerbal can live in the vessel. If you have two kerbals, then divide the number by two.

The best habitation module probably is the ‘Ranger’ Inflatable Habitation Module, but it requires materialKits and a kerbal in Eva to deploy it. Also cannot be retracted. So it is best as a second phase deployment. For small colonies, put a pair of those and forget.

As a first phase (bootstrap) the MKS ‘Ranger’ Mini-Habitation module is awesome. Lightweight, retractable, no requirements or kerbals in Eva needed. This gives 10 kerbal-months in 1.45 tons.

MKS Ranger Mini-Habitation Module

Like in agriculture, this can be boosted. In this case by the hab multiplier. Add a Observation Cupola per kerbal to get an extra 70% boost to your starting trip.

Putting all together

Let’s say we want to kolonize the moon. Start small by sending one single Kerbal. The engineer will be useful for configuring things later, the scientist gives boosts to agriculture, and the pilot requires less resources or habitation.

The first module should be the MKS ‘Duna’ Kerbitat. Add a pair of Observation Cupolas and two Nom-O-Matic 5000. Add 200 supplies and 100 fertilizer and we should get around 1 year and 57 days worth of food for a single kerbal. Remember to add an empty Mulch container and enable the Recycler built-in on MKS Duna module while on flight. With the recycler enabled, this should give us around 4.7 years worth of food.

Add a pair of MKS Ranger Mini-Habitation Module, and we get around 20 kerbal-months. Using the multiplier we get 3.5 years.

Finished module for exploration (8.7t)

This setup can be used for a long term base or for doing trips to other planets, as 3 years is usually enough for these.

After that time, just bring another kerbal, switch them, and bring more fertilizer. You’ll get 5 extra years.

Those MKS Duna Module come with deployable legs, but they aren’t spring-loaded, so usually I tend to add extra landing legs for a easier landing. My preferred ones for bases are the Wide Landing legs as they’re both spring loaded and have ground attaching, preventing the base from rolling.

Also, place a docking port on top to be able to expand the base later:

I use the Senior version as it is slightly easier to dock and more stable.

To send the base there, the best is to have a crane already in orbit and use it (docking!) to send the module to its final destination.

The finished module weigths 9.14 tons without engines, fuel or science experiments. This is the extra difficulty this mod imposes.

PD: I completely forgot to add batteries and solar panels! Don’t forget kerbals, greenhouses, recyclers and habitation modules require EC.