please note that the development of future spacecraft and their capabilities is subject to ongoing research and technological advancements. The values I provide are theoretical possibilities rather than specific predictions.
Maximum Velocity: The maximum velocity a spacecraft can achieve largely depends on the propulsion technology used. Currently, the most efficient propulsion method for deep space exploration is ion propulsion, which can achieve velocities up to 20-30 miles per second (32-48 kilometers per second). However, for interstellar travel, significantly higher velocities would be required.
In the realm of theoretical propulsion concepts, one promising idea is the concept of a "lightsail" or "photon sail." A lightsail spacecraft would use a large, ultra-thin sail to capture the momentum of photons emitted by a powerful laser or sunlight, allowing for extremely high velocities. Some estimates suggest that a lightsail spacecraft could potentially reach velocities as high as a significant fraction of the speed of light, such as 10-30% of the speed of light (67,108,720 to 201,326,160 miles per second).
Distance Traveled in One Year: If we consider the maximum velocity of 30 miles per second (48 kilometers per second) achievable with current ion propulsion, a spacecraft could travel approximately 2,592,000 miles per day (4,172,160 kilometers per day). In one year (assuming 365 days), it could cover a distance of roughly 946,080,000 miles (1,522,500,000 kilometers).
For a lightsail spacecraft capable of reaching a velocity of 10-30% of the speed of light (67,108,720 to 201,326,160 miles per second), it could potentially travel about 2.26 trillion to 6.77 trillion miles (3.64 trillion to 10.89 trillion kilometers) in one year.
Keep in mind that these figures represent hypothetical scenarios and the development of technology to achieve such velocities is still in progress.