VT - Attachment A - Performance Work Statement

Attachment A – PWS

Venous Thrombosis (VT)

9/25/2026

Venous Thrombosis (VT)
Performance Work Statement (PWS)

1. Description

The National Aeronautics and Space Administration (NASA) Human Research Program (HRP) has a requirement for application of current, enhanced, or novel approaches to surveil, reduce risk of, and/or prevent venous thrombosis (VT) during spaceflight. This topic includes preflight medical screening, individual risk assessment, monitoring approaches, and countermeasures for spaceflight VT.

2. Scope of Work

Work performed will focus on applied research and shall not include tissue chip/organoid pathophysiology development, Earth-independent decision-making support tools, emerging VT pharmaceutical treatments, or modeling (i.e., artificial intelligence, machine learning).
The Contractor shall provide all management, supervision, labor, personnel, materials, equipment, tools, supplies, facilities, and transportation necessary to perform all work required under this PWS.

3. Background

A VT was identified in the internal jugular vein (IJV) of an astronaut during a research study of fluids shifts in weightlessness (a). This incidental finding was subsequently confirmed by a clinically guided ultrasound examination with 2-D imaging, color Doppler, and compression (b). While the crewmember was successfully treated with anti-coagulants on-orbit and regression of the thrombus was observed over the course of therapy, the absence of spontaneous flow persisted through 90 days of treatment. Anti-coagulation therapy was discontinued 4 days before landing, and the astronaut was safely returned to Earth without further complications. No thrombus was detected 10 days after landing, and the astronaut was asymptomatic during the subsequent 6 months. Additionally, in a retrospective evaluation of the images from the research study, a partially occlusive thrombus was suspected in a second crewmember but it was not confirmed using standard clinical practices (a). Previously, Internal Jugular Vein (IJV) thrombosis was not a recognized concern for crew health during weightlessness, owing to its low terrestrial prevalence (c, d). Following this event, medical surveillance for VT was initiated among U.S. Orbital Segment astronauts (e). Current medical assessments required for International Space Station (ISS) astronauts include assessment of genetic predisposition to

Attachment A – PWS

Venous Thrombosis (VT)

9/25/2026

thrombosis and preflight magnetic resonance imaging of the head and neck (TWIST