Item from remembrance-of-earths-past by
A nuclear-pulse-accelerated lightsail probe — the first object humanity ever sent to intercept the Trisolaran fleet — carrying, in a frozen biopreservation chamber the size of a teacup, the brain of Yun Tianming.
The Staircase is humanity's most ambitious early-Crisis gambit and one of its strangest. Wade pushed it through the PDC over fierce opposition. Cheng Xin signed the launch order. Most of the nuclear charges miss-fire and the capsule veers off course; the Trisolaran fleet recovers it anyway, decades later. The brain inside, regrown by Trisolaran biology into a body again, becomes Yun Tianming, who eventually transmits the curvature drive home as a fairy tale.
A small capsule perhaps two meters across, gold-mirrored, attached by tethers to a kilometer-wide gossamer lightsail. Behind the sail at launch: a string of small nuclear charges meant to push it past the speed required to intercept the fleet centuries early. Inside the capsule: a brain in cryopreserved suspension, no body.