# Swarm Absolute Scalar Magnetometer
*sensor . products*

Helium-4 optically pumped scalar magnetometer flown on ESA Swarm for absolute magnetic-field intensity measurement and VFM calibration.

## Specifications
- **product status**: operational
- **deployment context**: orbital
- **manufacturer**: cea-leti
- **sensor**: {"instrument_family":"magnetometer","measurement_principle":"passive","measurement_type":"scalar","sensor_technology":"optically-pumped-scalar","dynamic_range_nT":[15000,65000],"sampling_rate_hz":1,"absolute_accuracy_nT":0.065,"noise_floor_pT_per_sqrtHz":1,"resolution_nT":0.1,"bandwidth_hz":0.4,"notes":"Nominal scalar acquisition is 1 Hz with 0.4 Hz low-pass filtering; burst mode can run at 250 Hz for health and noise checks."}
- **entity type**: sensor
- **last verified date**: 2026-06-08
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: cea-leti
- **attributes**: {"kind":"sensor","product_status":"operational","deployment_context":"orbital","manufacturer":"cea-leti","description":"Helium-4 optically pumped scalar magnetometer flown on ESA Swarm for absolute magnetic-field intensity measurement and VFM calibration.","sensor":"{\"instrument_family\":\"magnetometer\",\"measurement_principle\":\"passive\",\"measurement_type\":\"scalar\",\"sensor_technology\":\"optically-pumped-scalar\",\"dynamic_range_nT\":[15000,65000],\"sampling_rate_hz\":1,\"absolute_accuracy_nT\":0.065,\"noise_floor_pT_per_sqrtHz\":1,\"resolution_nT\":0.1,\"bandwidth_hz\":0.4,\"notes\":\"Nominal scalar acquisition is 1 Hz with 0.4 Hz low-pass filtering; burst mode can run at 250 Hz for health and noise checks.\"}"}
- **technology**: magnetometry
- **relevance**: in-scope

## Editorial
The Swarm Absolute Scalar Magnetometer is the helium-4 scalar magnetometer flown on ESA Swarm to measure magnetic-field intensity.[^wmo-asm] ASM provides absolute scalar measurements used to calibrate the Vector Field Magnetometer on the same spacecraft.[^esa-swarm-sensors]

CEA-Leti developed and manufactured ASM under CNES contract.[^esa-swarm-sensors] In nominal scalar mode it provides 1 Hz measurements with 0.4 Hz low-pass filtering, and in-flight analysis reports 65 pT maximum accuracy error after Level 1b corrections.[^springer-asm-vector-mode] On Swarm Alpha, the ASM payload status was active as of 2 February 2026.[^wmo-swarm-a]

## Compositional position
- swarm (missions) --[mission_payloads]--> Swarm Absolute Scalar Magnetometer

## Sources
- [esa-swarm-sensors] | Swarm new generation of sensors, ESA | https://www.esa.int/Applications/Observing_the_Earth/FutureEO/Swarm/New_generation_of_sensors | tier=agency-doc | accessed=2026-06-08
- [wmo-asm] | WMO OSCAR ASM instrument details | https://space.oscar.wmo.int/instruments/view/asm | tier=agency-doc | accessed=2026-06-08
- [springer-asm-vector-mode] | In-flight performance of the ASM vector mode on Swarm | https://link.springer.com/article/10.1186/s40623-015-0231-1 | tier=peer-reviewed | accessed=2026-06-08 | published=2015-04-25
- [wmo-swarm-a] | WMO OSCAR SWARM-A satellite payload status | https://space.oscar.wmo.int/satellites/view/swarm_a | tier=agency-doc | accessed=2026-06-08

---
Source: https://eo-atlas.org/products/sensor/swarm-absolute-scalar-magnetometer
Maintainer: SpectraWorks B.V. (CC-BY 4.0)