On what date did JWST reach the Sun-Earth L2 point?

JWST reached the Sun–Earth L2 point on 24 January 2022.

The milestone came nearly a month after Webb launched from French Guiana aboard an Ariane 5 rocket on 25 December 2021. Rather than travel directly to L2, the telescope made a carefully planned journey involving three course corrections. The final correction placed it into its intended halo orbit around the Sun–Earth L2 region.

L2 lies about 1.5 million kilometres from Earth, on the side opposite the Sun. From there, the Sun, Earth, and Moon remain in roughly the same direction, allowing Webb's large sunshield to keep its telescope and instruments cold. Webb does not sit motionless at L2; it loops around the point in a halo orbit while orbiting the Sun with Earth.

The date is sometimes confused with launch day or the dates of Webb's dramatic deployments. Its primary mirror wings were locked into place on 7 and 8 January, while arrival at L2 occurred later, on 24 January. The observatory then began months of alignment and commissioning.