HNX employs two complementary instruments that cover separate but overlapping ranges of the periodic table:

• The ENergetic Trans-Iron Composition Experiment (ENTICE)
  (10 < Z < 83)


• A charge detector employing three detector systems:
  - Two silicon arrays measure energy deposit
  - Two Cherenkov counters measure velocity
  - Two scintillating fiber hodoscopes measure trajectories

The Extremely-heavy Cosmic-ray Composition Observer (ECCO) (Z < 70)

• A giant (23mē) array of passive glass track etch detectors
  
• Designed to measure the abundance of actinide nuclei (clocks that measure the absolute age of galactic cosmic ray nuclei)
  
• Data are recovered in the lab post-retrieval, thus requiring the Space Shuttle as the launch/retrieval vehicle.