Experiments

Center for Microgravity Research

I am involved in a variety of experiments carried out in the Center for Microgravity Research. General information on the lab and the experiments I work on is provided in the sections below.

Center for Microgravity Research Website

About

The Center for Microgravity Research (CMR) is a joint venture of the University of Central Florida and Space Florida that conducts and facilitates research in microgravity sciences. The Center makes use of parabolic airplane flights, drop towers, suborbital rocket flights, and orbital flights. The Center’s educational activities include providing hands-on training and experience to college and university undergraduate and graduate students in the design, fabrication, and operation of space experiments.

Research

A broad array of fundamental research is enabled by the microgravity environment whether it is in a ground-based drop tower, parabolic airplane flights, or suborbital rocket flights. Each platform has advantages and a place in a broad scientific research endeavor. The research fields that are enabled by microgravity include:

  • Collisional and aggregation processes in protoplanetary disks
  • Collisional evolution of planetary ring systems
  • Evolution of the dusty surfaces of asteroids and small moons
  • Physical evolution of comet nuclei
  • Space Life Sciences
  • Fundamental fluid physics
  • Physics of granular media
  • Validation of space hardware and space operations
  • Crystal growth
  • Dusty plasma physics

The University of Central Florida has expertise in several of these research areas and promotes active research programs that will be leveraged by the Center for Microgravity Research.

CubeSat Particle Aggregation Collision Experiment: Q-PACE

Q-PACE (CubeSat Particle Aggregation and Collision Experiment) is a planned orbital spacecraft mission that will study the early stages of protoplanetary accretion by observing particle dynamical aggregation for several years. The CubeSat is currently being developed with a target launch date of NET September 2019.

My role: Ran numerical simulations to inform experiment design including choice of particle number density, designed the passive magnetic attitude control system, performed solar power generation and communication window analysis, and developed data compression procedure to downlink video data in timely fashion.

Q-PACE Wikipedia

Q-PACE Publication

Numerical simulation of mm and cm-size particles colliding under anticipated initial velocity distribution profile of 5 cm/s.

COLLisions into Dust Experiment: COLLIDE

COLLIDE-3

COLLIDE-3 is a Suborbital Experiment that consists of one (1) Impactor Box System contained within an aluminum vacuum chamber, a video recording system, and a logic unit. These components are all mounted to an aluminum baseplate. The experiment is performed with pre-determined impact parameters (target material, impactor mass, and impactor velocity). The experiment is fully automated using an accelerometer and an internal timed circuitry system. The video shown below was our lab’s first observation of a mass transfer event where a significant portion of granular material adheres to the surface of a projectile in a microgravity environment. This experiment is included in the analysis for my mass transfer paper in preparation.

COLLIDE-VG: Virgin Galactic SpaceShipTwo

We flew the COLLIDE-3 payload again on Virgin Galactic SpaceShipTwo’s inaugural flight to space in December 2018 and then again in February 2019. I designed the experiment plan for both flights, assisted with mechanical and electronic testing, and provided ground support on site. Analysis of the experimental results are ongoing.

Here I am describing the COLLIDE payload at the Virgin Galactic SpaceShipTwo launch site:

MultiCOLLIDE: Blue Origin New Shepard

We flew a modified iteration of the COLLIDE payload on the Blue Origin New Shepard launch vehicle in January 2019 that now included a multi-launcher system. I assisted with the experiment plan, and payload testing through Blue Origin’s flight simulation software. Analysis of the experimental results are ongoing.

Physics of Regolith in Microgravity Experiment: PRIME

PRIME is a parabolic flight campaign that is conceptually identical to the COLLIDE-3 experiment. We had 12 experiment boxes for each flight. I designed the experiment plan design for 3 of the PRIME campaigns, and provided ground and flight support for each flight.

Spring Pendulum Rebound in ‘No Gravity’ Environment: SPRING-E

Our lab has conducted several flight-based experiments designed to investigate low-velocity impacts of cm-scale projectiles into simulated planetary regolith. We have observed that certain impact events occurring at speeds less than 50 cm/s result in mass transfer from the target regolith onto the projectile. These flight campaigns are relatively expensive and time consuming; it is typically only possible to get a few data points each year and the experiments cost thousands of dollars. To study this phenomenon with significantly reduced cost and time constraints we developed an experimental apparatus that makes use of our laboratory drop tower (free-fall time ~0.75 s) that allows us to simulate the rebound portion of these mass-transfer collision events. The apparatus, affectionately known as SPRING-E for Spring Pendulum Rebound in ‘No Gravity’ Experiment, consists of a spring attached to a marble resting in a tray of regolith. When the apparatus is released from the top of the drop tower, the free-fall environment allows the spring to retract and pull the marble out of the regolith at a low acceleration (~ 1 m/s2). The experiments were initially conducted in open-air, but we have transitioned the apparatus to a bell-jar system capable of achieving < 500 mtorr pressures to better replicate an environment relevant to small, airless bodies and conditions during early planet formation.

SPRING-E with Vacuum Pump
Mass Transfer Event Examples

The cadence of data for our ground based experiment is much higher than for our flight campaigns with the ability to carry out 3-5 experiments a day. Data collection is ongoing, and a paper presenting a comparison of the drop tower mass transfer events to the parabolic and suborbital flight data is in preparation.

Our spring mechanism apparatus was useful as a proof of concept demonstrating that it is possible to simulate the rebound portion of low-velocity collision events that result in mass transferred from regolith onto a projectile. However, the current mechanism is limited in its ability to produce data directly comparable to the parabolic and suborbital flight campaigns because of the large rebound force applied to the marble by the spring, the marble velocity is not fine-tunable, and the apparatus is incapable of duplicating the lower rebound accelerations (~0.1 m/s2) observed in both the COLLIDE and PRIME experiments. Additionally, the marble tends to rotate away from the camera while lifting out of the regolith, yielding a subset of the data that is inconclusive as to whether mass transfer had occurred. Therefore, we developed an improved apparatus that consists of a rigid pulley mechanism controlled by a stepper motor that will provide us with precise control over the rebound velocity of a cm-size marble. With this method, we plan to increase the explored parameter space of microgravity collision events including projectile mass, material, and rebound velocity as well as regolith compaction, regolith grain type, and regolith size distribution.

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