2016.A.3.2. Q-PACE: A Long-Duration Microgravity Experiment on Planetesimal Formation

Author(s)

Joshua Colwell (1)
Julie Brisset (1)
Adrienne Dove (1)
Jürgen Blum (2)
Douglas Maukonen (1)

University of Central Florida, United States of America
Technische Universität Braunschweig, Germany

Session

A.3

Keywords

Microgravity, Planetary Rings, Planetesimals

Abstract

Previous experimental studies of the collisions between mm to cm-scale objects in the protoplanetary disk and in planetary ring systems have shown that simple deterministic models of collisions do not capture the range of outcomes. Nearly-identical particles colliding at similar speeds show a broad distribution of rebound velocities. Q-PACE (CubeSat Particle Aggregration and Collision Experiment) will provide data on a large number of collisions so that collisional outcomes relevant to the early stages of planet formation can be modeled stochastically rather than deterministically. Q-PACE is a 2U CubeSat selected by NASA’s Small Innovative Missions for Planetary Exploration (SIMPLEx) program and scheduled for launch into low Earth orbit in December 2017 with an anticipated mission duration of at least two years. Collisions will take place between four different particle samples at speeds up to 10 cm/s. Collisional damping will be recorded on high-frame-rate video. A precursor experiment, NanoRocks, on the International Space Station has provided a proof-of-concept for Q-PACE and preliminary science results at speeds down to ~ 1 mm/s.

Experience from NanoRocks suggests that collisions will fully damp after approximately 5 minutes. Each experiment run will thus generate 5 minutes of high-frame-rate video data. We will use an innovative data compression scheme in which uncompressed sample frames are downlinked for analysis and determination of an optimal compression algorithm. The compression parameters will be uplinked to Q-PACE and the video compressed on board for downlink. We are developing a high-data-rate downlink system of up to 1 Mbps to handle the data, but with limited coverage we anticipate approximately 1 week to handle a full experiment run. Over the course of the mission we will perform dozens of experiment runs, introducing dust aggregates and meteoritic chondrules into the experiment chamber in later stages of the experiment. The large number of collisions we observe and the low collision velocities obtainable with Q-PACE will expand the experimental database by orders of magnitude for collisions at this scale in the protoplanetary disk. The Q-PACE collisions are also directly relevant to studies of the collisional evolution of planetary ring systems.