Low Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) CubeSat



The Low-Latitude Ionosphere/Thermosphere Enhancements in Density (LLITED) CubeSat mission is a recently funded (2017) NASA HTIDs program. It is a 3-year grant with two 1.5U CubeSats  with a 1-year on-orbit mission life. Each CubeSat will host an ionization gauge (IG), planar ion probe (PIP), and GPS radio occultation sensor (GPSRO). The mission is to provide both ionosphere and thermosphere measurements related to the Equatorial Ionization Anomaly (EIA) and the Equatorial Temperature and Wind Anomaly (ETWA).  The EIA and ETWA are two of the dominant ionosphere/thermosphere interactions on the low-latitude duskside. While the EIA has been extensively studied both observationally and with modeling, the ETWA is less well known since observations are infrequent due to a lack of suitably instrumented spacecraft at appropriate altitudes. LLITED will, for the first time, provide coincident high resolution measurements of the duskside ionosphere/thermosphere at lower altitudes that will characterize and improve our understanding of the ETWA, provide insight into the coupling physics between the ETWA and EIA, and increase our knowledge of the duskside dynamics that may influence space weather.

​SAIL will design, build, calibrate and deliver the Planar Ion Probe (PIP) which is a gold plated planar Langmuir probe biased in the ion saturation region. PIP is depicted as the gold rectangle on the top plate of the LLITED CubeSat in the image above. The top plate will be within a few degrees of the RAM direction. PIP will provide absolute ion density for the LLITED science mission.

Planar Ion Probe Salient Features:

  • Total 17cm2 electronics board

  •  4 x 6 cm sensor plate with 1 cm wide guard electrode

  • Low mass components: instrument PCB 9 g, sensor 10 g, envelope 27 g

  • Power draw of 125 mW at nominal ion density (2 x 10^11 m-3)

  • Power draw of 250 mW at maximum ion density (2 x 10^13 m-3)

  • Instrument boot-up time ≤ 350 ms

  • Design resolution (noise floor resolution):

    • 306 pA (306 pA) = 3.13 x 10^8 m-3 (3.13 x 10^8 m-3) low gain

    • 3.09 pA (~70 pA) = 3.16 x 10^6 m-3 (~7.0 x 10^7 m-3) high gain

  •  better than 10% precision throughout the four decades of measurement

​More details about the mission can be found in the Small Satellite Conference Proceedings paper on LLITED. And more information on the PIP instrument can be found in the MS Thesis of Liam Gunter.