Point-of-Care Ultrasound in Spaceflight: Diagnostics When Ultrasound Is the Only Imaging
Also: ultrasound on ISS · remote-guided ultrasound · jugular vein screening · FAST in space
Distance from EarthGravity FieldsCardiovascularNeuro-ophthalmicRenal & GUImmune & HematologicPreflight & TrainingIn-flightPostflight RecoveryLEO short-durationLEO long-durationCislunar / Lunar orbitLunar surfaceMars transit & surfaceClinicianOperator / SFPResearcher
- Ultrasound is the only cross-sectional imaging on the ISS; non-physician crew can obtain diagnostic images when guided in real time by experts on the ground. ◆◆◆◆ High · F
- A crewmember with minimal sonography training completed the first FAST exam in space in about 5.5 minutes under remote guidance. ◆◆◆◇ Moderate · F
- In-flight scans of the internal jugular veins found stagnant or reversed flow in a substantial share of ISS crew and, rarely, thrombus; NASA now screens every crewmember for DVT and jugular flow anomalies. ◆◆◆◇ Moderate · F E
- Ocular ultrasound tracks globe flattening for SANS; renal ultrasound surveys for stones; handheld devices are now carried at landing sites and on commercial flights. ◆◆◆◇ Moderate · F E
- On the ground, ultrasound is ideal for returning flyers: no radiation, and it compares directly with in-flight images. ◆◆◆◇ Moderate · E
Proposed certainty (◆ High → ◇ Very low) and evidence-type tags: F flight · A analog · M model/animal · C computational · E expert/operational/standards. Grades are AI-proposed and pending medical reviewer confirmation. How we grade.
What to do
Imaging a returning flyer
- Prefer ultrasound where it answers the question — no radiation (see Radiation) and directly comparable with in-flight images.
- Neck/upper limb swelling or pain → duplex of internal jugular, subclavian and arm veins. NASA’s schedule includes post-landing jugular scans [5].
- Flank pain or hematuria → renal and bladder ultrasound for stone or hydronephrosis [7].
- Vision change → ocular ultrasound for globe flattening / optic nerve sheath, alongside fundoscopy and OCT [6].
- Trauma at landing → eFAST as usual; landing teams carry a handheld ultrasound [8].
Jugular thrombosis: what NASA does (operational practice, for education)
If an in-flight scan shows thrombus, NASA’s brief describes anticoagulation regardless of flow pattern — apixaban 10 mg twice daily for 7 days, then 5 mg twice daily — with no EVA or heavy resistance exercise for at least 30 days, and stopping treatment doses at least 48 hours before landing (24 hours for prophylactic doses). Crew with stasis plus a family history, thrombophilia, or VTE-raising hormones may receive prophylaxis (2.5 mg twice daily) [5]. These are case-by-case guidelines, not SMF recommendations.
Overview
Spacecraft have no CT, MRI or X-ray. Ultrasound is small, safe and versatile, and has been on the ISS for two decades. The model is remote guidance: a crewmember holds the probe while an expert on the ground watches the live image and directs them.
| Application | Evidence |
|---|---|
| Trauma (FAST) | First in-space FAST: a minimally trained crewmember, remotely guided over a 2-second satellite delay, acquired all four standard windows in ~5.5 minutes [1] |
| Echocardiography | Six crew, 2 h preflight training plus just-in-time e-learning, remote guidance; most differences were due to technician rather than spaceflight; spaceflight-related changes were not clinically significant [2] |
| Jugular veins | In 11 ISS crew, IJV area rose from ~10 mm² (seated preflight) to ~70 mm² in flight and pressure from ~5 to ~21 mmHg; stagnant or reverse flow and a thrombus were found [3]; one case report of in-flight IJV thrombosis managed with anticoagulation [4] |
| Eye | Ocular ultrasound for globe flattening in flight (MRI on the ground); crew get about 1 h ocular ultrasound training [6] |
| Kidney | JSC surveillance: 282 studies in 73 astronauts (30 pre/post-flight pairs) showed no increase in mineralized renal material after flight; untrained crew using autonomous guidance software obtained 25 high-quality kidney/bladder images [7] |
| Commercial | Inspiration4 civilian crew used handheld ultrasound in flight [9] |
Clinical considerations
- Screening the jugular veins: NASA requires every crewmember to be screened for DVT and IJV flow anomalies with duplex ultrasound and breathing/compression maneuvers; example schedule for a 180-day mission: 12 and 3 months before launch, flight days 30 and 60, 42 days before return, landing day and 45 days after [5].
- Stasis is the worrying sign: NASA’s expert panel judged stagnant flow the most concerning pre-thrombotic indicator [5].
- Limits: image quality depends on the operator and guidance; at Mars, communication delays prevent live guidance, so autonomous software and stronger training are being developed [7].
- Artifacts may behave differently: in a pig study, the kidney-stone “twinkle” artifact faded at about 0.8% CO2 — a level ISS has reached — so a negative scan does not exclude a stone [7].
Mission-type differences
| Mission | Ultrasound role |
|---|---|
| LEO short / commercial | Handheld devices; mostly research and reassurance |
| LEO long (ISS) | Routine screening (veins, eyes) and diagnosis with real-time ground guidance [5][6] |
| Lunar | Near real-time guidance still feasible; main imaging for injuries on the surface |
| Mars | No live guidance; autonomous AI-assisted acquisition and interpretation needed [7] |
Terrestrial parallels
- Emergency and critical care POCUS — eFAST, lung, DVT, ocular (optic nerve sheath diameter) — essentially the same exams.
- Tele-ultrasound for rural, military and prehospital care.
- Upper-extremity / jugular DVT — on Earth usually catheter- or cancer-related; in space, linked to headward fluid shift and stasis [3][5].
Gaps
- Natural history and best management of in-flight venous stasis and thrombosis.
- Diagnostic accuracy of autonomous ultrasound for exploration missions.
- Whether spaceflight changes artifacts used for diagnosis [7].
Deeper dive: lower-body negative pressure and jugular flow
The 2019 jugular study also tested lower-body negative pressure (LBNP) in flight, a countermeasure that pulls fluid back toward the legs; the study design included IJV measures at ~50 and ~150 flight days with and without LBNP, and seated, supine and 15° head-down tilt measures before and after flight [3]. LBNP is also being studied as a SANS countermeasure — see SANS.
Commercial spaceflight notes
Handheld ultrasound has already flown on commercial missions [9]. For participants with VTE risk factors, a preflight jugular and leg vein scan gives a baseline for comparison if symptoms develop.
Clinical pearls
- If a returning astronaut has a swollen neck or arm, think jugular/upper-extremity thrombosis first — and check what anticoagulant they took in flight.
- Ultrasound on Earth after flight lets you compare apples with apples: the same modality used in orbit.
Evidence profile
- Overall certainty
- ◆◆◆◇ Moderate (proposed)
- Evidence types
- F · Flight dataE · Expert / operational / standards
- Literature through
- 2026-10-14
NASA-STD-3001 requirements referenced 4
| Requirement | Title | Plain-language meaning |
|---|---|---|
| [V1 3003] (n) | In-Mission Preventive Health Care | Includes monitoring for venous patency (jugular thrombosis). |
| [V1 3004] | In-Mission Medical Care | Diagnostic capability appropriate to the mission's medical risks. |
| OCHMO-STD-100.1A [6041] | Screening for DVT and Venous Flow Anomalies | Every crewmember screened with duplex ultrasound of bilateral internal jugular veins. |
| [V2 7045] | Medical Equipment Usability | Equipment must be usable by non-physician crew. |
IDs as published in NASA-STD-3001 Vol. 1 Rev C (2023-09-15) and NASA-STD-3001 Vol. 2 Rev F (2026-07-14). NASA-STD-3001 binds NASA programs; it is not a regulation for commercial flights. Paraphrased; read the standard for exact wording. Standards quick reference.
References 9
- Sargsyan AE, Hamilton DR, Jones JA, et al. FAST at MACH 20: clinical ultrasound aboard the International Space Station. J Trauma. 2005;58(1):35-39. doi:10.1097/01.TA.0000145083.47032.78 PMID:15674147 Peer-reviewed F
- Hamilton DR, Sargsyan AE, Martin DS, et al. On-orbit prospective echocardiography on International Space Station crew. Echocardiography. 2011;28(5):491-501. doi:10.1111/j.1540-8175.2011.01385.x PMID:21535119 Peer-reviewed F
- Marshall-Goebel K, Laurie SS, Alferova IV, et al. Assessment of jugular venous blood flow stasis and thrombosis during spaceflight. JAMA Netw Open. 2019;2(11):e1915011. doi:10.1001/jamanetworkopen.2019.15011 PMID:31722025 Peer-reviewed F
- Auñón-Chancellor SM, Pattarini JM, Moll S, Sargsyan A. Venous thrombosis during spaceflight. N Engl J Med. 2020;382(1):89-90. doi:10.1056/NEJMc1905875 PMID:31893522 Peer-reviewed F
- NASA OCHMO. Venous Thrombosis in Spaceflight. Medical Technical Brief OCHMO-MTB-007 (2026). www.nasa.gov/wp-content/uploads/2026/01/ochmo-mtb-007-venous… NASA E
- NASA OCHMO. Spaceflight Associated Neuro-ocular Syndrome (SANS). Medical Technical Brief OCHMO-MTB-001 (2024). www.nasa.gov/wp-content/uploads/2024/02/ochmo-mtb-001-sans.p… NASA E
- NASA Human Research Program. Evidence Report: Risk of Renal Stone Formation (2024). humanresearchroadmap.nasa.gov/evidence/other/2024%20Renal%20… NASA F
- NASA OCHMO. Crew Medical Support for Entry, Descent, and Landing. Technical Brief OCHMO-TB-051 (2026). www.nasa.gov/wp-content/uploads/2026/05/ochmo-tb-051-crew-me… NASA E
- Jones CW, Overbey EG, Lacombe J, et al. Molecular and physiological changes in the SpaceX Inspiration4 civilian crew. Nature. 2024;632:1155-1164. doi:10.1038/s41586-024-07648-x PMID:38862026 Peer-reviewed F
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- 2026-10-14
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