SORTIE (Scintillation Observations and Response of the lonosphere to Electrodynamics)
February 10, 2025
Mission Objectives
The SORTIE mission is an investigation of wave-like perturbations in the region of space called the ionosphere, a region with a large population of charged particles that have been ionized by energetic photons from the sun.
By deploying a small satellite in this part of Earth’s atmosphere, SORTIE seeks to:
- Discover the sources of wave-like plasma perturbations in the F-region atmosphere and
- Determine the relative role of dynamo action and more direct mechanical forcing in the formation of wave-like plasma perturbations
SORTIE is a NASA-funded partnership between the UT Dallas W.B.H. Center for Space Sciences, ASTRA LLC and the Air Force Research Laboratory (AFRL).
Mission Methodology
To investigate ionospheric plasma perturbations, SORTIE deployed a small satellite in a low altitude, medium inclination orbit, populated with special sensors that directly measure properties of the ambient plasma. The SORTIE satellite is a shoe-box sized satellite called a CubeSat, equipped with miniaturized sensors designed to collect the needed data. By using a CubeSat, the SORTIE mission was executed
at a relatively low cost and short schedule.
The measurement method employed for SORTIE is to measure the phase delay between the ion drift velocity components parallel and perpendicular to the magnetic field and the plasma density perturbations. SORTIE on-orbit data is composed of:
- High cadence plasma densities collected by the AFRL micro Planar Langmuir Probe (uPLP)
- Vector ion drift with the UTD mini lon Velocity Meter (mIVM)
SORTIE deployment from ISS
UTD’s Contribution — the mIVM
The SORTIE MIVM is the first CubeSat compatible sensor developed and provided by the UTD Center for Space Sciences. The mIVM combines two legacy sensor functions in one sensor:·
- Retarding Potential Analyzer (RPA): Measures lon Temperature, Density, Composition and Ram Drift Velocity
- lon Drift Meter (IDM): Measures Cross Track Drift Velocity Vector
By using commercially available electrical components instead of ultra-high reliability and radiation tolerant parts typically used for space-flight hardware, UTD was able to significantly reduce the size, weight and power of the mIVM compared to past designs. Though reduced in size, the mIVM science data product quality is similar to the larger and more expensive legacy sensors.
Small Size: 10 x 10 x 6.6 cm
Low Mass: 720 g
Low Power: 370 mW
Low Data Rate: 512 bytes/sec
lon Drift Range: +/-1,000 m/s
lon Drift Resolution: 3 m/s
Ion Drift Accuracy: 10 m/s
Provides lon Temperature, Density, and O+/H+ Ratio
Launch and Deployment
SORTIE was carried to the International Space Station (ISS) on the SpaceX CRS-19 Dragon resupply mission, launched on December 5, 2019. The satellite was deployed to orbit from the ISS using the NanoRacks Double Wide Deployer on February 19, 2020. The initial SORTIE orbit was at approximately 400 km altitude at an inclination of 51.6°. Lacking propulsion to maintain orbit altitude, the SORTIE satellite uses natural orbital drag conditions to eventually reduce altitude, ultimately burning up in the Earth’s atmosphere at the end of mission life.
Mission Results
SORTIE celebrated 2 years of on-orbit operation in 2022, exceeding the minimum operation requirement by a factor of two. The mission marks the first successful deployment and operation of a CubeSat compatible lon Velocity Meter which was shown to produce high-quality data with minimal resources. Mission scientists are using the data collected by SORTIE to further our understanding of plasma perturbations in the ionosphere.