On March 29 2025, Earth passed through the Moon’s shadow. So did PUNCH. As each spacecraft passed through the shadow, its solar array momentarily stopped generating power.
On March 29, 2025, many folks went outside to catch a glimpse of the partially eclipsed Sun, as the Earth carried them through the Moon’s shadow. PUNCH, orbiting high overhead, also passed through the shadow. Orbital velocities are high, so each spacecraft passed through the darkest part of the partial eclipse (the Moon’s penumbra) at a slightly different time, about eight minutes apart. Even though the instruments’ doors are still closed for commissioning, PUNCH registered the eclipse. During the brief interval of darkest shadow, the solar arrays couldn’t keep up with on-board power usage and each spacecraft briefly switched to battery power, using slightly less than 1% of its battery capacity to keep operating normally through the brief gap.
(This is PUNCH Nugget #5; nuggets are archived at the PUNCH website.)
