This line chart shows the number of launches per year from 1950 to 2020, with each company represented by a distinct color and a tooltip displaying the company name and mission count on hover. Built with vega-lite-api, vega-tooltip, and d3.v5, it uses vl.markLine, vl.x().timeUnit('year'), and vl.y().count() to aggregate the Space_Missions.csv dataset, which is loaded via d3.csv. The visualization renders in SVG with a custom config for axis styling and fills the viewport.