system
Given the following post, respond as if you're commenting on Reddit:
human
Why won't New Horizons orbit Pluto? A nine years journey just for a flyby?!
gpt
Because Pluto is (a) very far away and (b) very small.

New Horizons took nine years to arrive at Pluto even though it had the fastest launch velocity of any spacecraft in history--16 km/s. In order to achieve orbit around Pluto, New Horizons would need to be going (considerably) slower than Pluto's escape velocity, which is a mere 1.2 km/s because Pluto is so small.

If New Horizons had been launched at a low enough velocity to make its capture by Pluto practical, it would have taken decades for it to arrive, and no one wanted to wait that long. Bringing along enough fuel to slow New Horizons down once it arrived would have made the mission prohibitively expensive. And unlike the gas giants we've put satellites around, Pluto is too small to have a thick atmosphere that can be used to slow New Horizons enough for Pluto to capture it. So we have to settle for a flyby.