# Can we collide two Nano Spacecraft moving at 20% speed of light?

Nano spacecrafts are gram level silicon chips that will be accelerated to 20% of the speed of light to reach Alpha Centauri in 20 years.

I wonder if we can break the weight limitation by shooting multiple spacecraft and connecting them after the acceleration. To test this idea, I need your help with calculating the numbers. Let's assume that we want to connect two spacecraft, $$A$$ and $$B$$.

• $$A$$ is accelerated before $$B$$.
• $$B$$ is accelerated to a speed slightly bigger than $$A$$
• it takes $$t$$ days for $$B$$ to catch up $$A$$

As $$B$$ will get closer to $$A$$ it will have better precision aligning on $$A$$ collision path, but it will also require more energy to navigate $$B$$

Please calculate what precision is needed to collide with $$A$$ and what maneuvering speed $$B$$ needs to do it.

This question doesn't contain all the details for making this calculation. I am looking for a realistic example to understand if such a mission is even possible, so please feel the gaps with realistic assumptions about the problem.

• Many existing spacecraft could get through the gaps... – Solar Mike Jan 14 at 22:18
• @SolarMike, I don't think there are many existing spacecraft with gram level weight. Could you please expand on what do you mean? – Ilya Gazman Jan 14 at 22:28