Opportunities for interstellar dust detection by the Interstellar Probe

Interstellar Probe is an ambitious mission concept, to reach interstellar space (up to 1000 AU). Its launch date is between 2030 and 2042 and its goals cover different fields of science from planetary science, heliophysics (heliosphere), to astronomy. One main goal is to significantly expand our knowledge about our heliosphere, the interstellar medium, and how both interact with each other. Among many other instruments, the space probe is planned to carry a dust mass spectrometer that will be able to capture dust particles and measure their composition. This will be especially useful for measuring the interstellar dust of the local interstellar medium that continuously streams through the solar system and has been directly detected for the first time with the Ulysses spacecraft in the 1990s. The mass distributions from such in situ dust detections in the solar system so far have shown a significant discrepancy compared to the results from astronomical observations. We performed a series of simulations of the interstellar dust trajectories and distribution inside the solar system and use them to predict the ability of the Interstellar Probe to measure interstellar dust particles and how this ability is affected by different spacecraft trajectories and dust detector setups. We also discuss how the filtering of small dust particles at the boundary regions of the heliosphere affects our predictions and indicate how in situ dust measurements can be used to constrain the filtering process. In general, most of the dust particles can be measured if the spacecraft moves towards the nose of the heliosphere. However, we also find a significant correlation between the presence of small dust particles (<0.3 microns) in the inner solar system and the phase of the solar cycle which is caused by the filtering effect of the solar magnetic field via the Lorentz force. Inside the heliosphere, the interstellar Probe may be able to detect and analyze up to 1 interstellar dust particle per day for particle sizes >0.1 micron and many more of the smaller particles, depending on the state of the solar magnetic field and the dust filtering at the boundary of the heliosphere. Outside the heliosphere, the absence of dust filtering should increase the detection rate of small particles (<0.1 microns) to more than 10 per day.