INCA

Ionic Neutron Content Analyzer Mission

PI: Dr. Steven Stochaj

The Ionospheric Neutron Content Analyzer (INCA) is a 3U CubeSat being built by students at New Mexico State University carrying a scintillator - silicon photomultiplier-based neutron detector being built by NASA’s Goddard Space Flight Center (GSFC). The INCA mission will for the first time, study the latitude and time dependencies of the neutron spectrum in low Earth Orbit (LEO), and has been selected for a flight through NASA's Cube Sat Launch Initiative (CSLI). These measurements will be accomplished using a new directional neutron spectrometer which is being developed in conjunction with NASA’s GSFC and the University of New Hampshire (UNH). INCA will focus on albedo neutrons; however, the instrumentation will also be sensitive to solar neutrons. Albedo neutrons, produced via interaction of high-energy cosmic rays and solar particles with molecules in the upper atmosphere, represent a hazard for spacecraft as they can pass through most shielding, and can cause single event effects (SEE’s) in electronics. Furthermore, these neutrons decay with a lifetime of less than 15 minutes into a proton and an electron, which tend to become trapped in the Earth’s magnetic field forming the lower radiation belts. This process, known as cosmic ray albedo neutron decay (CRAND), is the primary source of the particles comprising the radiation belts. Current models for CRAND neutrons are taken from high altitude balloon flights performed in the 1970’s; as such, the current data represents a static model which does not reflect time or latitude dependencies. Since neutron flux is believed to be dependent on latitude and solar activity, the use of current models presents a risk for spacecraft in LEO. The data acquired from the INCA mission will help to expand space weather models and contribute to further understanding of the radiation belts.

Mission Objectives

1. Demonstrate Functionality of SiPM’s (a never flown technology) in LEO

2. Measure latitude dependence of neutron flux in LEO

3. Measure temporal dependence of neutron flux in LEO

4. Detect a solar neutron (stretch goal)

Science Overview

Mission measures the Neutron flux and energy as a function of time and latitude in low earth orbit.

Informs models on the formation of Earth's radiation belts, as Neutrons coming off of the Earths atmosphere are a significant contributor to the population of the radiation belt.

Informs models involving radiation doses for aircraft crews.

Spacecraft Architecture

3U spacecraft based on a COTS CubeSat kit

1U avionics stack

2U neutron detector

Deployable solar panels

Two processors