# GOCE Electrostatic Gravity Gradiometer (EGG)
*sensor . products*

Six-accelerometer electrostatic gravity gradiometer flown as the main GOCE payload.

## Specifications
- **manufacturer**: onera
- **product status**: retired
- **deployment context**: orbital
- **sensor**: {"instrument_family":"gravimeter","gravimeter_principle":"gravity-gradiometry","gravity_field_resolution_halfwavelength_km":100,"geoid_accuracy_cm":1,"gravity_anomaly_accuracy_mgal":1,"orbit_altitude_km":254,"notes":"Six three-axis electrostatic accelerometers arranged as three orthogonal gradiometer arms; GOCE operated in drag-free low Earth orbit for static gravity-field mapping."}
- **entity type**: sensor
- **last verified date**: 2026-06-08
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: onera
- **attributes**: {"kind":"sensor","manufacturer":"onera","product_status":"retired","deployment_context":"orbital","description":"Six-accelerometer electrostatic gravity gradiometer flown as the main GOCE payload.","sensor":"{\"instrument_family\":\"gravimeter\",\"gravimeter_principle\":\"gravity-gradiometry\",\"gravity_field_resolution_halfwavelength_km\":100,\"geoid_accuracy_cm\":1,\"gravity_anomaly_accuracy_mgal\":1,\"orbit_altitude_km\":254,\"notes\":\"Six three-axis electrostatic accelerometers arranged as three orthogonal gradiometer arms; GOCE operated in drag-free low Earth orbit for static gravity-field mapping.\"}"}
- **relevance**: in-scope

## Editorial
GOCE Electrostatic Gravity Gradiometer (EGG) was the primary gravity instrument on ESA's GOCE mission. It used six three-axis electrostatic accelerometers mounted in three orthogonal gradiometer arms, each 50 cm long, to measure gravity-gradient components in orbit [^esa-goce-instruments]. GOCE used the gradiometer with drag-free control at low altitude to map Earth's static gravity field and geoid at about 100 km spatial resolution [^esa-goce-operations][^esa-goce-visuals]. ONERA completed the accelerometer sensor heads for delivery to the GOCE prime contractor before spacecraft integration [^esa-goce-scientists].

## Compositional position
- goce (missions) --[mission_payloads]--> GOCE Electrostatic Gravity Gradiometer (EGG)

## Sources
- [esa-goce-instruments] | GOCE instruments, ESA | https://www.esa.int/Applications/Observing_the_Earth/FutureEO/GOCE/Instruments | tier=agency-doc | accessed=2026-06-08
- [esa-goce-operations] | GOCE operations, ESA | https://www.esa.int/Enabling_Support/Operations/GOCE_operations | tier=agency-doc | accessed=2026-06-08
- [esa-goce-visuals] | GOCE mission visuals, ESA Earth Online | https://visuals.earth.esa.int/satellites/goce | tier=agency-doc | accessed=2026-06-08
- [esa-goce-scientists] | Scientists view GOCE satellite, ESA | https://www.esa.int/Applications/Observing_the_Earth/FutureEO/GOCE/Scientists_view_GOCE_satellite | tier=agency-doc | accessed=2026-06-08

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