Instrument Development and Capabilities for ICE-8Ball: Ice-Cryo Encapsulation Eight By Balloon

The ICE-Ball cloud probe, "Ice Cryo Encapsulation by Balloon" has undergone incremental development across 38 cirrus cloud penetration flights since it's 2016 inception (e.g. Magee et al. 2021). The instrument takes a unique approach to achieve high resolution measurements of in-situ ice microphysics through robotic collection and hermetic cryo-storage of ice and aerosol particles. The in-cloud particle cyro-encapsulation process is followed balloon cut-down and parachute return with GPS-aided retrieval. Cryo-stored samples are then transported to lab facilities for analyses via cryo scanning electron microscopy. Example ice particle images and measurements are shown from four flights during an October 2021 field campaign at the ARM-Southern Great Plains site. Since the 2021 field campaign, ICE-Ball has undergone further development to collect multiple differentiated samples and to promote more efficient collection of aerosols and small particles. Cryo-cell geometry and imaging techniques are also under development to improve energy dispersive x-ray spectroscopy (EDX) of scavenged and ice-nucleating aerosols, and to improve capacity for 3D particle reconstruction and automated particle analyses. This presentation provides details of the current stage of instrument development (ICE-8Ball), and seeks interest in new capabilities or deployment strategies or collaborations.

	2021 Specifications (ICE-Ball)	Present specifications (ICE-8Ball)	In Development
Passive sample collection	2 independent cryo-cells, timer closure 7mm dia. x 6 mm depth	8 independent, altitude-defined cells 6 mm dia x 3 mm depth	no change
Cryo-sample hermetics	Open at low altitude Timed magnetic closure above cloud top	Sealed until opened in-cloud Magnetic closure by GPS altitude	no change
Active small particle collection	none	none	1 slow-suction pumped cryo-cell 0.45 micron silver filter membrane
Cloud video	HD side-pointing flight video	HD side-pointing flight video	no change
In-situ measurements	On-board pressure, temp, RH, accelerometer	High-resolution internal GPS added	Addition of Vaisala sounding package
Package total weight	2-4 kg	no change	no change
Ascent rate	4-6 m/s	no change	no change
Maximum altitude	20 km	no change	no change
Tracking	SPOT GPS satellite Tracking APRS GPS Radio Tracking, surface cell GPS	no change	no change