About

Dr. Rich Whittle is an Assistant Professor in the Department of Mechanical and Aerospace Engineering at UC Davis. He leads the Bioastronautics and eXploration Systems (BXS) Laboratory within the UC Davis Center for Space Flight Research (CSFR). His research focuses on understanding the physiological changes induced in the human body by the space environment and developing tools, technologies, and countermeasures to facilitate operations and minimize risks in human spaceflight. Dr. Whittle completed his Ph.D. in Aerospace Engineering at Texas A&M University and holds a Master of Science in Astronautics and Space Engineering from Cranfield University, as well as a Postgraduate Diploma in Strategic Management and Leadership from Stratford Business School. He also earned an MA/MEng in Engineering from the University of Cambridge. Prior to his academic career, he served as an airborne infantry officer, including operational service in Helmand Province, Afghanistan, and later as an engineering officer in the British Army from 2009 to 2023. Dr. Whittle is a member of several professional organizations, including the American Institute of Aeronautics and Astronautics (AIAA), the Aerospace Medical Association (AsMA), the International Council on Systems Engineering (INCOSE), and the British Interplanetary Society, where he is a Fellow.

Research topics

• Internal medicine
• Medicine
• Physics
• Mathematics
• Anesthesia
• Geometry
• Anatomy
• Ophthalmology
• Biology
• Environmental health
• Demography
• Cardiology

Selected publications

• Case study: dose-dependent internal jugular vein response to lower body negative pressure in microgravity quantified by the flow directionality index

  Journal of Applied Physiology · 2026-03-26

  articleOpen access

  Microgravity alters jugular venous flow, which in turn may increase thrombosis risk. In this graded lower body negative pressure experiment performed in true microgravity conditions during parabolic flight, we show that increasing negative pressure improves venous drainage in a dose-dependent manner. A new flow directionality index reveals subtle changes in flow not captured by existing grading systems, supporting lower body negative pressure as a practical countermeasure to mitigate stagnant internal jugular vein blood flow during future space missions.

  PublisherDOI

• Cardiovascular response to altered gravity in healthy adults: Insight from graded tilt testing

  Physiological Reports · 2026-02-01 · 1 citations

  articleOpen access

  Microgravity exposure during spaceflight induces a thoracocephalic fluid shift that affects the cardiovascular system both during flight and after return to Earth. As the proportion of female astronauts increases, it is essential to understand how altered gravity impacts cardiovascular function across sexes. In this study, we examined sex differences in central hemodynamics, vascular morphology of the common carotid artery and internal jugular vein (IJV), and IJV pressure during graded head-up to head-down tilt (+45° to -45° in 15° increments) in healthy participants (12 female and 12 male adults). A strong gravitational dependence on almost all variables was observed, except for oxygen consumption. Only a few variables showed significant sex differences, and these include cardiac output, total peripheral resistance, rate pressure product, oxygen consumption, and sympathovagal balance (LF/HF ratio). Overall, hemodynamic, vascular morphology, and IJV pressure responses to tilt were largely similar between sexes. The additional female gravitational dose-response curves augment our previous, male-only database of cardiovascular responses to tilt. Together, these results provide a unique and more comprehensive normative baseline to support the development of spaceflight countermeasures as well as other terrestrial clinical applications, such as surgery in Trendelenburg or prone positioning.

  PublisherDOI

• Bias in Surface Electromyography Features across a Demographically Diverse Cohort

  arXiv (Cornell University) · 2026-04-15

  preprintOpen accessSenior author

  Neuromotor decoding from upper-limb electromyography (sEMG) can enhance human-machine interfaces and offer a more natural means of controlling prosthetic limbs, virtual reality, and household electronics. Unfortunately, current sEMG technology does not always perform consistently across users because individual differences such as age and body mass index, among many others, can substantially alter signal quality. This variability makes sEMG characteristics highly idiosyncratic, often necessitating laborious personalization and iterative tuning to achieve reliable performance. This variability has particular import for sEMG-based assistive devices and neural interfaces, where demographic biases in sEMG features could undermine broad and fair deployment. In this study, we explore how demographic differences affect the sEMG signals produced and their implications for machine learning-based gesture decoding. We analyze the data set provided by, in which we derive 147 common sEMG features extracted from 81 demographically diverse individuals performing discrete hand gestures. Using mixed-effects linear models and partial least squares (PLS) analysis, which take into consideration demographic variables (including age, sex, height, weight, skin properties, subcutaneous fat, and hair density), we identify that 33\% (49 of 147) of commonly used sEMG features show significant associations with demographic characteristics. These results may help guide the development of fair and unbiased sEMG-based neural interfaces across a diverse population.

  PublisherDOI

• From Sight to Touch: Haptic Sensory Integration Can Facilitate Multi-Limb Coordination

  IEEE Transactions on Haptics · 2026-01-01 · 1 citations

  articleOpen access

  Humans possess an innate ability to seamlessly coordinate movement across multiple limbs, whether driving a motor vehicle, playing a musical instrument, or performing other daily tasks. Here, supplemental sensory information, such as haptic feedback, can enhance this coordination in applications ranging from controlling teleoperated robots to prosthetic limbs and collaborative robotics. Yet, a critical gap remains in our understanding of how visual and haptic information are integrated within sensorimotor feedback systems, as well as the extent to which these sensory channels may serve as substitutes for one another. To address this gap, we conducted an experiment investigating how sensory feedback can be incorporated in a multi-limb coordination task. To determine the degree to which visual or haptic feedback dominates in multi-limb coordination, 25 participants performed a virtual cursor-to-target task using both upper limbs (via a joystick controller) and one lower limb (via a foot pedal controller). Throughout the task, we systematically manipulated visual and haptic feedback, using a vibrotactile haptic feedback algorithm that delivered task-relevant information to all three limbs. We assessed participants' task performance measures relating to trial success rates, completion times, ability to move their limbs in coordination, and overall movement efficiency. Additionally, participants completed a cognitive workload questionnaire to evaluate their perceived task difficulty level and cognitive demands. Our findings indicate that haptic feedback can effectively substitute for one degree of visual information (cursor movement along one axis). We found no significant difference between conditions where all visual cues were presented in the task and the condition where one aspect of visual feedback was replaced by haptic feedback. These results suggest that haptic feedback can, to an extent, serve as a viable alternative to visual feedback in multi-limb coordination tasks.

  PublisherDOI

• Bias in Surface Electromyography Features across a Demographically Diverse Cohort

  arXiv (Cornell University) · 2026-04-15

  articleOpen accessSenior author

  Neuromotor decoding from upper-limb electromyography (sEMG) can enhance human-machine interfaces and offer a more natural means of controlling prosthetic limbs, virtual reality, and household electronics. Unfortunately, current sEMG technology does not always perform consistently across users because individual differences such as age and body mass index, among many others, can substantially alter signal quality. This variability makes sEMG characteristics highly idiosyncratic, often necessitating laborious personalization and iterative tuning to achieve reliable performance. This variability has particular import for sEMG-based assistive devices and neural interfaces, where demographic biases in sEMG features could undermine broad and fair deployment. In this study, we explore how demographic differences affect the sEMG signals produced and their implications for machine learning-based gesture decoding. We analyze the data set provided by, in which we derive 147 common sEMG features extracted from 81 demographically diverse individuals performing discrete hand gestures. Using mixed-effects linear models and partial least squares (PLS) analysis, which take into consideration demographic variables (including age, sex, height, weight, skin properties, subcutaneous fat, and hair density), we identify that 33\% (49 of 147) of commonly used sEMG features show significant associations with demographic characteristics. These results may help guide the development of fair and unbiased sEMG-based neural interfaces across a diverse population.

  PublisherOA PDF

• Integrative cardiovascular dose–response to graded lower‐body negative pressure

  Experimental Physiology · 2025-05-14 · 2 citations

  articleOpen access1st authorCorresponding

  Lower-body negative pressure (LBNP) has been posited as a potential spaceflight countermeasure to counteract the physiological deconditioning related to fluid shifts in microgravity. However, open questions remain regarding the magnitude of LBNP that should be applied. We systematically characterized the cardiovascular effects of LBNP and quantified the effect size of varied LBNP doses across different parts of the cardiovascular system. Twenty-four subjects (12 male and 12 female) were exposed to graded LBNP, increasing from 0 to -50 mmHg in 10 mmHg increments, in both supine (0°) and 15° head-down tilt postures. At each pressure level, subjects first underwent a 6 min stabilization period to reach a steady-state cardiovascular response. We then assessed a wide range of variables, including those related to the systemic circulation, cardiovascular control, and haemodynamics of the eyes and neck. Building on the experimental data, dose-response curves were constructed using a Bayesian multivariate hierarchical modelling framework to quantify the effect size of every variable considered when subjected to LBNP. The methodology allows direct comparison of the variables and the underlying structural relationships between them. Furthermore, we demonstrated the potential for LBNP to reduce jugular venous flow stagnation, which is considered one of the major health risks during human spaceflight. The dose-response curves and effect sizes generated from this research effort establish the most comprehensive framework available to date that characterizes physiological responses to LBNP. These results directly inform the development of countermeasures to mitigate the negative effects of spaceflight, including cardiovascular deconditioning, spaceflight-associated neuro-ocular syndrome and venous thromboembolism events.

  PublisherDOI

• Quantifying Prosthetic Embodiment: Interactions Between Agency, Ownership, and Peripersonal Space in a Closed-Loop Sensorimotor Task

  Research Square · 2025-09-22

  preprintOpen access
  PublisherOA PDFDOI

• The effects of limb position and grasped load on hand gesture classification using electromyography, force myography, and their combination

  PLoS ONE · 2025-04-10 · 6 citations

  articleOpen access

  Hand gesture classification is crucial for the control of many modern technologies, ranging from virtual and augmented reality systems to assistive mechatronic devices. A prominent control technique employs surface electromyography (EMG) and pattern recognition algorithms to identify specific patterns in muscle electrical activity and translate these to device commands. While being well established in consumer, clinical, and research applications, this technique suffers from misclassification errors caused by limb movements and the weight of manipulated objects, both vital aspects of how we use our hands in daily life. An emerging alternative control technique is force myography (FMG) which uses pattern recognition algorithms to predict hand gestures from the axial forces present at the skin's surface created by contractions of the underlying muscles. As EMG and FMG capture different physiological signals associated with muscle contraction, we hypothesized that each may offer unique additional information for gesture classification, potentially improving classification accuracy in the presence of limb position and object loading effects. Thus, we tested the effect of limb position and grasped load on 3 different sensing modalities: EMG, FMG, and the fused combination of the two. 27 able-bodied participants performed a grasp and release task with 4 hand gestures at 8 positions and under 5 object weight conditions. We then examined the effects of limb position and grasped load on gesture classification accuracy across each sensing modality. It was found that position and grasped load had statistically significant effects on the classification performance of the 3 sensing modalities and that the combination of EMG and FMG provided the highest classification accuracy of hand gesture, limb position, and grasped load combinations (97.34%) followed by FMG (92.27%) and then EMG (82.84%). This points to the fact that the addition of FMG to traditional EMG control systems offers unique additional data for more effective device control and can help accommodate different limb positions and grasped object loads.

  PublisherDOI

• Radiation Protection Systems: A Review of Active and Passive Interplanetary Protection Systems and Introduction to a Proposed Mathematical Model for Magnetic Shielding

  2025-01-03

  reviewSenior author

  The risk of radiation carcinogenesis is one of the key issues in future exploratory spaceflight requiring mitigation. This paper aims to outline the current state of the art research on the interplanetary radiation environment, radiation protection systems, radiation health risks, and introduces a project to quantify the power costs of active-magnetic shielding. In recent years, research into Galactic Cosmic Rays, Solar Particle Events, and their associated interactions has led to a much greater understanding of the limitations and challenges in the development of protection systems for future space missions. In particular, the contribution of heavy ions has been identified as a major danger to manned spacecraft. Additionally, the importance of secondary radiation and, hence, the consequences for the design of passive shielding, has been a notable area of research over the last decade. Active shielding remains an area of active research, however, there is a need to characterize and model the interaction of the active component with any passive shielding resulting from spacecraft structural material due to the coupled nature of particle interactions. In this paper, we outline our aims and preliminary work to develop a finite-element model to rapidly quantify this coupled active-passive shielding effect and the associated protection afforded to biological material. The model will subsequently be used to conduct a trade study of requirements for coupled active magnetic radiation protection systems. Finally, the model and results of the trade study will be applied to design reference Martian missions.

  PublisherDOI

• Integrative cardiovascular dose-response to graded lower body negative pressure

  bioRxiv (Cold Spring Harbor Laboratory) · 2024-11-18

  preprintOpen access1st author

  Abstract Background Lower body negative pressure (LBNP) has been posited as a potential spaceflight countermeasure to counteract the physiological deconditioning related to fluid shifts in micro-gravity. However, open questions remain as to the magnitude of LBNP that should be applied. We systematically characterized the cardiovascular effects of LBNP and quantified the effect size of varied LBNP doses across different parts of the cardiovascular system. Methods Twenty-four subjects (12M, 12F) were exposed to graded LBNP from 0 mmHg to −50 mmHg in 10 mmHg increments, both in supine (0°) and 15° head-down tilt postures. We measured the steady-state response in a large range of variables, including those related to the systemic circulation, cardiovascular control, and hemodynamics of the eyes and neck. Results Building on the experimental data, dose-response curves were constructed using a Bayesian multivariate hierarchical modeling framework to quantify the effect size of every variable considered when subjected to LBNP. The methodology allows direct comparison of the variables and the underlying structural relationships between them. Further, we demonstrated the potential for LBNP to reduce jugular venous flow stagnation, which is considered one of the major health risks during human spaceflight. Conclusions The Dose-response curves and effect sizes generated from this research effort establish the most comprehensive framework available to date that characterizes physiological responses to LBNP. These results directly inform the development of countermeasures to mitigate the negative effects of spaceflight, including cardiovascular deconditioning, spaceflight-associated neuro-ocular syndrome, and venous thromboembolism events. Key Points Summary Lower body negative pressure (LBNP) has been posited as a potential countermeasure for multiple risks associated with spaceflight, including cardiovascular deconditioning, spaceflight-associated neuro-ocular syndrome, and venous thromboembolism events. However, the specific LBNP dose needed to mitigate these risks is still unknown. We constructed the LBNP dose-response curves in supine and 15° head-down-tilt positions to quantify the acute response of a large variety of hemodynamics, autonomic, ocular, and neck variables across a range of LBNP levels. We also used a Bayesian multivariate modeling framework to identify significant relationships between variables and to compare their effect sizes under different levels of LBNP. In addition, results indicate that LBNP is a promising countermeasure to reduce jugular venous flow stagnation occurring during microgravity exposure. This study constitutes the most comprehensive analysis of cardiovascular hemodynamics, autonomic, and cephalad response to LBNP to date. This framework informs the development of countermeasures to mitigate the detrimental effects of spaceflight.

  PublisherOA PDFDOI

Frequent coauthors

• Ana Diaz‐Artiles

  17 shared

• Bonnie J. Dunbar

  Texas A&M University

  6 shared

• Daniel Selva

  Texas A&M University

  4 shared

• Poonampreet Kaur Josan

  Texas A&M University System

  4 shared

• Nathan Keller

  4 shared

• Nikita Beebe

  Texas A&M University

  4 shared

• Prachi Dutta

  Texas A&M University

  4 shared

• Oscar Balcells-Quintana

  Universitat Politècnica de Catalunya

  4 shared

Education

• PhD, Aerospace Engineering

  Texas A&M University

  2023

• MSc, Astronautics and Space Engineering

  Cranfield University

  2017

• MA, Engineering

  University of Cambridge

  2014

• MEng, Engineering

  University of Cambridge

  2011

Awards & honors

• British Interplanetary Society (BIS, Fellow)