Abstract
This paper reports some of the initial results from the Taylor University, Technology, and TEST satellite (TSAT), especially results related to the new Globalstar communication network connection coverage, spacecraft temperature, magnetic field variations, reentry heating data, and new plasma science data measurements at extremely low altitudes down to 120km. TSAT is a two unit CubeSat (2.9kg), launched April 18, 2014 on a SpaceX rocket to the ISS (CRS-3 service). TSAT was released into a 325 km circular, 51.6° inclination orbit. This environment enabled unique extremely low-earth orbit (ELEO) data, but consequently only had a lifetime of 40 days. The primary objectives for TSAT were: 1) validating and characterizing the commercial Globalstar link capacity and coverage, 2) making new low-altitude ELEO measurements, 3) making plasma density measurements using a Langmuir Probe, and 4) educating a future workforce in STEM fields (Taylor University engineering program Capstone and other classes). A pioneering feature of TSAT is the near real time and continuous Globalstar link coverage, so that measurements could be made in the uncharted ionosphere region 120 to 300 km. This new region that TSAT explored is called the Extremely Low Earth Orbit (ELEO) region. At present, the near earth space region between 40 and 300 km is vastly underexplored since only sounding rocket flights (about 20 min) take measurements in this region, at only a few locations. Reasons for exploring this vast region of the earth’s upper atmosphere with small satellites include: 1) an advanced understanding of climate; specifically Sun-Earth connection using real-time in situ data for global ionosphere models, and 2) new discovery potential for atmospheric, ionospheric, and magnetospheric underpinnings and dynamics. LEO satellites entering into the ELEO region spiral into the atmosphere within a few weeks and are not designed for ELEO measurements because of cost and scale factor. A new class of satellites can be proposed to study this under-represented region of the space weather field; niche small satellites to explore the ELEO region. This paradigm has been demonstrated by TSAT. Monte Carlo simulations have been used to calculate the force and torques on TSAT, as well as on more aerodynamic satellites, so that they can survive to make measurements further down into the atmosphere for extended periods of time. Additional enablers of ELEO CubeSats include: 1) ISS resupply missions routinely have secondary slots in the ELEO region, 2) limited probability of space debris collisions in this region, and 3) the suitability of this region for ion engine thrusters to counteract drag, extending satellite operations beyond previously achievable mission lifetimes. The relatively low cost of these ELEO CubeSats, coupled with relatively long mission duration in the ELEO region, produces a large amount of useful data per unit cost.
Presentation
TSAT Globalstar ELaNa-5 Extremely Low-Earth Orbit (ELEO) Satellite
This paper reports some of the initial results from the Taylor University, Technology, and TEST satellite (TSAT), especially results related to the new Globalstar communication network connection coverage, spacecraft temperature, magnetic field variations, reentry heating data, and new plasma science data measurements at extremely low altitudes down to 120km. TSAT is a two unit CubeSat (2.9kg), launched April 18, 2014 on a SpaceX rocket to the ISS (CRS-3 service). TSAT was released into a 325 km circular, 51.6° inclination orbit. This environment enabled unique extremely low-earth orbit (ELEO) data, but consequently only had a lifetime of 40 days. The primary objectives for TSAT were: 1) validating and characterizing the commercial Globalstar link capacity and coverage, 2) making new low-altitude ELEO measurements, 3) making plasma density measurements using a Langmuir Probe, and 4) educating a future workforce in STEM fields (Taylor University engineering program Capstone and other classes). A pioneering feature of TSAT is the near real time and continuous Globalstar link coverage, so that measurements could be made in the uncharted ionosphere region 120 to 300 km. This new region that TSAT explored is called the Extremely Low Earth Orbit (ELEO) region. At present, the near earth space region between 40 and 300 km is vastly underexplored since only sounding rocket flights (about 20 min) take measurements in this region, at only a few locations. Reasons for exploring this vast region of the earth’s upper atmosphere with small satellites include: 1) an advanced understanding of climate; specifically Sun-Earth connection using real-time in situ data for global ionosphere models, and 2) new discovery potential for atmospheric, ionospheric, and magnetospheric underpinnings and dynamics. LEO satellites entering into the ELEO region spiral into the atmosphere within a few weeks and are not designed for ELEO measurements because of cost and scale factor. A new class of satellites can be proposed to study this under-represented region of the space weather field; niche small satellites to explore the ELEO region. This paradigm has been demonstrated by TSAT. Monte Carlo simulations have been used to calculate the force and torques on TSAT, as well as on more aerodynamic satellites, so that they can survive to make measurements further down into the atmosphere for extended periods of time. Additional enablers of ELEO CubeSats include: 1) ISS resupply missions routinely have secondary slots in the ELEO region, 2) limited probability of space debris collisions in this region, and 3) the suitability of this region for ion engine thrusters to counteract drag, extending satellite operations beyond previously achievable mission lifetimes. The relatively low cost of these ELEO CubeSats, coupled with relatively long mission duration in the ELEO region, produces a large amount of useful data per unit cost.
