Travel times at different speeds
Cruise speeds only, ignoring the time spent accelerating and braking:
| Speed | Example | Time to Proxima |
|---|---|---|
| 17 km/s | Voyager 1 today | ≈ 75,000 years |
| 50 km/s | Fast electric propulsion | ≈ 25,000 years |
| 3–5 % c | Nuclear pulse (Project Orion studies) | ≈ 85–140 years |
| 12 % c | Fusion (Project Daedalus study) | ≈ 35 years |
| 20 % c | Laser light sail (Breakthrough Starshot) | ≈ 21 years |
| c | Light | 4.24 years |
Why the fast options carry so little
The faster the drive, the smaller the payload so far: a light sail at 20% c would carry a probe of about a gram, while a nuclear pulse ship could carry thousands of tonnes much more slowly. A signal from Proxima also needs 4.24 years to come back to Earth.