Could a time dialtion effect at near FTL speeds used to space apart in time the arrival of multiple ships to a distant destination?
Let's say there's a terraformable planet somewhere in the Milky Way Galaxy many light years away from the Solar System. Instant FTL travel is not possible ie you can't reach destination within reasonable amount of time for a generation of humans(couple weeks/years/decades). The journey takes many hundreds if not thousands of standard Earth years for the observer.
Multiple Terraforming and Colonizing ships are launched either at the same time or within reasonable interval for our civilization(months/years/decades). The idea is that those ships arrive to the destination multiple millions of years apart each preparing the planet for another.
- The Atmospheric Processing Unit ship arrives first and starts shifting local atmosphere to that close to Earth's which would enable simple life. The process takes however long it needs, be it several thousand years or millions.
- Then comes the Life Genesis Ship whose job is to create microcosmos life on that planet out of raw minerals(guided abiogenesis) that will in turn accumulate enough "biomass" to sustain more complex ecosystem. I would assume this process would be the longest taking dozens or hundreds of millions of years.
- Multiple waves of Seeding ships with complex life arrive next spaced apart millions of years to enable the continious growth and development of ecosystem on that planet until becomes near identical to our own.
- Final ship brings the template for Humans and tools to enable newly cloned populations to form an advanced civilization. The plausibility of this scenario would be explored in another question.
All sips are AI guided and carry digital DNA, all critters are built on site from either raw materials or microcosmos biomatter. Redundancy and durablity are ensured by careful planning and calculation ie each step will perform its' job before the next ship arrives(no sheep on a grassless methane filled death world).
Could such an endeavour be accomplished using Time Dilation effect? Total amount of time on the destination planet from the APU arrival unitl Human creation should be within several dozen millions of years. Yet ships themselves can't travel from their point of view for said duration.
Could the ships be launched in reverse order?
EDIT: ships themselves can't be traveling for millions of years from their perspective. The travel time should be reasonable for each of them to maintain integrity and still be operable once it arrives to a destination. Say within hundreds or thousands of years on the active journey.
The plausibility of continious ecosystem development and human civilization creation aren't a factor in this particular question.
Fluff: Nobody cares what happens to humans on Earth by the time the new civilization is created. Plotwise some of the planets have developed a bizzare yet human compatible ecosystmes or even sentient life forms of their own. There's an instance where one of the APU's arrived after human colony was already established but regressed to feudalism and started converting atmosphere into a toxic one due to an error.