The first of two IVMs, which is designated IVM-A based on its location on the spacecraft (facing forward), started End Item Testing (EIT) this week. The EIT is a thorough functional checkout including calibration over temperature and serves as the entry point baseline for environmental testing. Environmental testing will include EMI/EMC, Vibration and Thermal Vacuum testing which simulate the launch and flight environments as closely as possible. Testing will be completed in about eight weeks. 

While the IVM enjoys many years of heritage, the ICON IVM has improvements and modifications that will produce measurements of the plasma drift with unprecedented sensitivity to achieve the ICON science goals. 

The second IVM (IVM-B) fabrication is following closely behind IVM-A and is in the final phases of test and assembly. IVM-B faces in the aft direction on the spacecraft during normal operations, when the remote sensing optical instruments view the northern hemisphere. However, it will be activated during operations when the spacecraft is rotated to allow the optical instruments to view the southern hemisphere.