Program: GS-2019B-FT-102

The New Horizons (NH) spacecraft is currently in its Kuiper Extended Mission phase, during which it is taking high phase angle (near perpendicular) observations of a handful of Kuiper Belt Objects (KBOs). This an opportunity afforded only by the spacecraft's current location within the main Kuiper Belt. Combined with the proposed, and other ground based observations, the high phase photometry from NH will allow the characterization of each target's full phase curve, and thus a characterization of each targeted KBO's surface properties, including micro-/macroscopic roughness, albedo, and porosity. From an intensive discovery and follow-up campaign, we have identified a handful of KBOs conducive to NH observations, but their ephemerides are currently too uncertain to target with the NH-LORRI imager. These ephemerides must be improved before the scheduled December NH observing window, or the opportunity for high phase angle observations will be lost. This program is to gather rapid critical astrometric data of our 5 targets before the candidates set below the horizon. We propose a simple, yet historically effective imaging sequence requiring a total 4.85 hours of photometric, dark conditions. This will improve ephemerides sufficiently for targeting by NH, thus ensuring this exceptionally rare scientific opportunity is not lost forever.