Calibration and performance of the Interstellar Dust Experiment (IDEX) onboard the Interplanetary Mapping and Acceleration Probe (IMAP) Mission

The Interstellar Dust Experiment (IDEX) is an impact-ionization time-of-flight mass spectrometer aboard NASA’s Interstellar Mapping and Acceleration Probe (IMAP), launched in September 2025 and operating at the Sun–Earth L1 Lagrange point. IDEX combines a large sensitive area (>600 cm²), high mass resolution (m/Δm > 200 at m = 100 u), and a wide dynamic range to measure the mass, flux, dynamics, and elemental and chemical composition of interstellar and interplanetary dust particles. The instrument’s performance has been validated through extensive laboratory calibration using iron, platinum-coated olivine, and aluminum particles with masses from approximately 3 × 10⁻¹⁸ to 10⁻¹⁴ kg and impact velocities of 4–50 km s⁻¹. In flight, IDEX operates in the ambient space environment, where it is exposed to interplanetary Lyman-α radiation and galactic cosmic rays. Many of the dust particles detected by IDEX in space are substantially larger than those achievable in laboratory accelerators and therefore generate significantly larger impact charges. This presentation provides an overview of the in-flight performance of IDEX, focusing on key instrument parameters and their comparison with laboratory calibration results.