written by Christian Bühler
A new civilization is born
Imagine a planet in an extrasolar system far away. It looks a little bit like our earth. You see blue oceans and huge continents. In the next moment a star ship enters the silence sending out a fleet of robot ships. You watch them beginning to build bases on the surface and in the orbit of the planet. As the constructions grow bigger and bigger you decide to find out more about the ship. You fly slowly around the ship watching the two powerful engines and the shimmering hull, still not knowing why it was sent. You reach the front end wondering about the huge antennas receiving signals from somewhere far away. Suddenly you hear some noise from inside the ship. After listening for a while you slowly recognize it must be a baby which has began to cry. What happened? The star ship you have discovered is a seed ship bringing a new civilization to the world beneath you.
You do not know what a seed ship is. Okay, let me explain. A seed ship is an interstellar spacecraft which is able to transport embryos or gametes over long distances. In order to keep them save and healthy it acts most of its flight like a huge fridge, because the unborn humans can only survive such long travel times in a frozen state. Close to the target system this “fridge” is transformed into some kind of brood chamber. Next the chamber begins to grow up the gametes or embryos to babies. After a few years when they have become older, the settlement can start. The two main questions that appear in this scenario are about transportation and how to parent and educate the children. The answers especially to the second question are quite difficult and controversial as you will see below.
A closer look at the transportation options
Right now, you might be able to imagine how the whole scenario of a seed ship settlement might look like. What I want to do here is to go further into detail. So let´s start at the beginning. What are the different ways to transport unborn humans to the stars?
– The first option is to send frozen embryos to the target system
– The second option goes one step back and you send donated egg and sperm cells
– The last option is to send only genetic information and produce the required egg and sperm cells at the planet
you want to settle.
The last option might be not feasible at the moment, because there is no system such as a biosequencer that can create the sperm or egg cells. So let’s have a closer look at the two remaining possibilities.
Both options for frozen embryos and frozen sperm and egg cells may be no problem due to the action of freezing. This is already state of the art. But an interstellar trip might last over more than a hundred years and we do not know if the cells or the embryos might take serious damage over such a long period of time. Today we only know that children were raised of embryos or gametes which are not stored longer than 20 years. We need a few more long term studies to confirm that freezing is no problem. These studies will cause ethical difficulties because you would need human embryos as test objects.
Another requirement for the freezing options is that there must be some kind of artificial uterus to grow the embryos or gametes. An artificial uterus is a machine which makes it possible to grow embryos or gametes outside of a woman’s body. These machines might become necessary because there are no adult humans on a seed ship. If we go back to the brood chamber example it makes no sense to carry eggs to a planet if there is no possibility to hatch them. An artificial uterus does not yet exist for humans, but Nick Otway invented one for sharks. Due to this fact, it can be assumed that during the next decades this technology might also become feasible for humans.
Raising the babies
Now let´s go one step further. The “new settlers” are transported safely to the target system and are now grown up in the artificial wombs. But this leads us to the next problem. It is necessary to parent those children and provide proper education in every field that is essential for the establishment of a new settlement.
One option might be to provide the required education by robots. But there are several disadvantages to “robot nannies”. One problem is the need of an advanced artificial intelligence for robots in order to parent and educate children. That might not be such a big issue because before we are able to send an interstellar spacecraft to another star, this technology might already be invented, as the spacecraft will require advanced artificial intelligence. Whether or not this type of artificial intelligence can be modified to satisfy the requirements of a “robot nanny” is an open question. The greater trouble is to test if it is really possible to use “robot nannies”. We cannot grow up thousands of babies at the target planet and hope everything will work out, without having done several tests beforehand. This causes a big ethical problem. We cannot do these tests on animals like we do for medicine. We must perform the tests on human children even if we do not know the results. Our society and I think almost everyone else does not agree with using children as laboratory rats.
Solving the “robot nanny” problem
So we still have the problem how to parent and educate children at their new home. One possibility is to form “teacher ships”. These ships are a combination of seed ships with sleeper ships. These are interstellar spacecraft which transport hibernating people to the target planet. If you want to find out more about sleeper ships and hibernation please feel free to read Daniel’s blog article. For example, let’s assume that the sleeper ship part of the teacher ship is a habitat for about 25.000 people with a hibernation chamber in which at the beginning only 1.000 adult crew members hibernate. After 25 years of journey these adults are woken up. At the same time 4.000 babies are grown up in the artificial wombs. Now the adults can parent and educate them. This education period will last about another 20-25 years. At the end of this wake phase there are over 5.000 well educated adults. Everyone is send back to hibernation again for 25 years. In the next step 20.000 babies are grown up. At the same time the adults are woken up and able to parent and educate the newborns. After the second education phase, which will also last for 20-25 years, about 25.000 educated adults live in the spacecraft´s habitat. At this point of the journey the teacher ship enters the target system. After reaching the target planet and the building of orbital bases or bases on the surface, more and more embryos or gametes can be grown up until the whole civilization is established. Sequencing the hibernation and education phases in a manner that only let’s a small part of the population awake might allows to drastically reduce the habitat size and life-support system requirements.
A second option might be to combine a world ship with a seed ship. In this case the seed ship part of the world ship is only an additional freezing chamber which is used to transport the unborn babies. The world ship brings e.g. 25.000 people to the target planet and after building orbital bases or bases on the surface the embryos or gametes can be grown up. The 25.000 adults which live on the world ship than can parent and educate the newborns. That means 25 years later we have a population of about 125.000 well educated people living at the target planet if we use the same number of babies per adult as it was used for the teacher ship.
These options require much more mass than a pure seed ship, but if we compare it to other possibilities like sleeper ships or even world ships without gametes or embryos with the same mass we can send much more people to another planet, as we carry the rest of the whole civilization as gametes or embryos in the “backpack”. This ensures a higher genetic variability over longer periods of time after colonization. We come to the conclusion that seed ships or modified seed ships seem to be a good option for manned interstellar spaceflight, if associated technical problems of cryogenics, artificial wombs and education are solved. Nevertheless the associated ethical problems are obvious and further research has to be done in every subarea before a technically and ethically viable solution can be proposed.Picture: