As we approach PUNCH launch, I'm thinking a bit about the orbit. We will fly in a 650km altitude dawn/dusk orbit, which means we fly over the poles directly overhead at sunrise and sunset everywhere, every day. That keeps the spacecraft in sunlight nearly all the time, so (a) we can collect power with our solar panels and (b) we can see the corona around the clock.
That sets our ideal launch time, which is about 6pm (or 6am) wherever we launch from. That's because sunrise (or sunset) is a place. Each location on Earth goes under that place at the corresponding (local) time.
There's a nuance to the orbit: because Earth goes around the Sun, the actual location of the Sun on the sky changes from day to day. If we launched into a perfect polar orbit over the dawn/dusk line, then three months later we'd be in a perfect polar orbit over the noon/midnight line. So we need to change the plane of the orbit each day, to keep the right geometry. We fly in a special Sun-synchronous orbit.
If Earth were a perfect sphere, then satellite orbits would all keep the same plane forever. But Earth isn't a perfect sphere. Because we're spinning around (once per day), Earth is slightly oblate: the equator bulges out a little bit. You can think of it as a perfect sphere, with a little extra stuff piled up around the equator. The equatorial bulge tends to pull the northern and southern parts of the orbit back toward the equator: it applies a torque to the overall orbit, twisting every satellite's orbit to flatten in toward the equator. But satellites are in circular motion, so the orbits don't flatten. Instead they precess like a gyroscope, rotating slowly around Earth's polar axis like a child's top as it spins on a table.
The precession rate of each orbit depends on the altitude and inclination of the orbit. That means it's adjustable. The PUNCH orbit is inclined ever so slightly from polar, so that we precess one full circle every year. That keeps us in the Sun most of the time.
Why "most"? Because Earth's axis is tilted! As a result, the Sun can be up to 23.4° above or below the ecliptic (at the solstices). That means we pass briefly through the Earth's shadow on each orbit for a few weeks around the unfavorable solstice.
There's another oddity to our orbit: we "should" launch at about 6pm from wherever we launch, but in fact we're planning to launch a little after 7pm local time from Vandenberg Space Force Base. That's because our sister mission, SPHEREx, needs to avoid pointing at the Sun ever. To accommodate that, SpaceX is launching us at night. But that places us into the wrong orbit! (7am/7pm instead of dawn/dusk). It's about 15° away from the orbit we want. So right after we achieve orbit, SpaceX points the top stage away from the Sun and, over Antarctica, thrusts laterally to torque our orbit around to the right plane.
That sounds minor, but it's a huge flex on their part. Turning the orbital plane by nearly 15° requires over 2 km/sec of delta-vee. Because of the weirdness of Tsiolkovsky's rocket equation, that almost doubles the total fuel load required. Falcon 9 (which is launching us) has a huge capacity, and SPHEREx and PUNCH together are pretty small compared to that capacity. So it's no big deal for them to "peel out" a bit as they hoist us.