Copyright © National Academy of Sciences. All rights reserved.
Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON SOLAR WIND-MAGNETOSPHERE INTERACTIONS
247
and the response of the ionosphere-thermosphere system to this input, in particular the outflow back to
the magnetosphere.
Mission Implementation and Strategy. The fundamental design of the MISTE mission concept is two identical spacecraft in highly inclined elliptical orbits with apogees 180˚ out of phase, as shown in Figure 9.12.
The two satellites can then be positioned on their orbits to obtain magnetic conjunctions so that the energy
input, the ionospheric heating and acceleration, and the outflow can be measured simultaneously. With
apogee at 5,000-km altitude, the satellites will pass through the auroral acceleration region and observe
the energization of the precipitating electrons and the wave heating and acceleration of the ionospheric
ions. Perigee will vary from the topside ionosphere (500-km altitude) to below the F-layer peak (200-km
altitude) in order to measure the range of energy deposition processes capable of causing ionospheric
outflow. With an 80˚ orbital inclination, apogee will precess, allowing for this magnetic alignment to cover
the entire high-latitude region. By varying the positions of the satellites along the orbit tracks, a span of
intersatellite distances during these alignments can be sampled.
The notional mission has two dual-spinner spacecraft (spin axis perpendicular to the orbit), with a
despun portion of each satellite with faces maintained in the ram and nadir directions and the other portion
at a high spin rate of 15 rpm. The despun portion provides high-cadence measurements of cold particle
populations and high-cadence auroral imaging. The faster-spinning portion enables the measurement of
three-dimensional velocity-space distributions of ions and electrons. It also accommodates long spin-plane
booms for high-resolution electric field measurements.
MISTE is designed to make a comprehensive suite of measurements to understand high-latitude energy
input and ionospheric outflow. See Figure 9.13 for an example of the breadth of measurements from MISTE.
To measure the low-altitude heating, the despun portion includes in situ sensors for measuring the neutral
density, neutral winds, ion and neutral mass composition, and ion velocity. The input electromagnetic
energy and electromagnetic waves that drive particle acceleration will be measured with axial electric
field booms, four wire booms, and a magnetometer. The axial booms will be mounted to the despun
platform, with one protruding through the center hole in the spinning section, while the wire booms are
on the spinning platform.
The thermal and suprathermal ion and electron measurements, which provide both the input precipitating particle energy and the response to this input, are made by a combination of sensors. Sensors located
at the ends of booms measure the very-low-energy ionospheric electron and ion three-dimensional velocity
distributions in the 0.1- to ~20-eV range, outside the spacecraft’s sheath. Body-mounted sensors will cover
ions and electrons over the plasma-sheet energy range from 20 eV to ~50 keV, including ion composition.
A final in situ detector will measure the precipitating flux of 50-keV to 5-MeV electrons.
To give a broader context to the in situ measurements, two remote sensing instruments are included. An
ultraviolet auroral imager will provide the regional context of the energy input to the upper atmosphere. An
active sounder experiment will remotely sense the plasma density along the magnetic field line below the
spacecraft. Together, these two instruments will provide a three-dimensional view of the region in which
the in situ measurements are made.
The primary objective of the MISTE mission concept is to quantify the amount of ionospheric outflow
given a particular intensity of electromagnetic or particle energy input to the upper atmosphere. Therefore,
the primary instrumentation of MISTE is the in situ thermal and suprathermal particle detectors and the
electric and magnetic field instruments. These observations could be made from a simpler mission design
of twin single-spin spacecraft. That is, a critical subset of the MISTE objectives could be obtained with a
dramatically reduced payload and mission concept. Ground-based observations of the neutral atmosphere
Solar and Space Physics: A Science for a Technological Society
REPORT OF THE PANEL ON SOLAR WIND-MAGNETOSPHERE INTERACTIONS
247
and the response of the ionosphere-thermosphere system to this input, in particular the outflow back to
the magnetosphere.
Mission Implementation and Strategy. The fundamental design of the MISTE mission concept is two identical spacecraft in highly inclined elliptical orbits with apogees 180˚ out of phase, as shown in Figure 9.12.
The two satellites can then be positioned on their orbits to obtain magnetic conjunctions so that the energy
input, the ionospheric heating and acceleration, and the outflow can be measured simultaneously. With
apogee at 5,000-km altitude, the satellites will pass through the auroral acceleration region and observe
the energization of the precipitating electrons and the wave heating and acceleration of the ionospheric
ions. Perigee will vary from the topside ionosphere (500-km altitude) to below the F-layer peak (200-km
altitude) in order to measure the range of energy deposition processes capable of causing ionospheric
outflow. With an 80˚ orbital inclination, apogee will precess, allowing for this magnetic alignment to cover
the entire high-latitude region. By varying the positions of the satellites along the orbit tracks, a span of
intersatellite distances during these alignments can be sampled.
The notional mission has two dual-spinner spacecraft (spin axis perpendicular to the orbit), with a
despun portion of each satellite with faces maintained in the ram and nadir directions and the other portion
at a high spin rate of 15 rpm. The despun portion provides high-cadence measurements of cold particle
populations and high-cadence auroral imaging. The faster-spinning portion enables the measurement of
three-dimensional velocity-space distributions of ions and electrons. It also accommodates long spin-plane
booms for high-resolution electric field measurements.
MISTE is designed to make a comprehensive suite of measurements to understand high-latitude energy
input and ionospheric outflow. See Figure 9.13 for an example of the breadth of measurements from MISTE.
To measure the low-altitude heating, the despun portion includes in situ sensors for measuring the neutral
density, neutral winds, ion and neutral mass composition, and ion velocity. The input electromagnetic
energy and electromagnetic waves that drive particle acceleration will be measured with axial electric
field booms, four wire booms, and a magnetometer. The axial booms will be mounted to the despun
platform, with one protruding through the center hole in the spinning section, while the wire booms are
on the spinning platform.
The thermal and suprathermal ion and electron measurements, which provide both the input precipitating particle energy and the response to this input, are made by a combination of sensors. Sensors located
at the ends of booms measure the very-low-energy ionospheric electron and ion three-dimensional velocity
distributions in the 0.1- to ~20-eV range, outside the spacecraft’s sheath. Body-mounted sensors will cover
ions and electrons over the plasma-sheet energy range from 20 eV to ~50 keV, including ion composition.
A final in situ detector will measure the precipitating flux of 50-keV to 5-MeV electrons.
To give a broader context to the in situ measurements, two remote sensing instruments are included. An
ultraviolet auroral imager will provide the regional context of the energy input to the upper atmosphere. An
active sounder experiment will remotely sense the plasma density along the magnetic field line below the
spacecraft. Together, these two instruments will provide a three-dimensional view of the region in which
the in situ measurements are made.
The primary objective of the MISTE mission concept is to quantify the amount of ionospheric outflow
given a particular intensity of electromagnetic or particle energy input to the upper atmosphere. Therefore,
the primary instrumentation of MISTE is the in situ thermal and suprathermal particle detectors and the
electric and magnetic field instruments. These observations could be made from a simpler mission design
of twin single-spin spacecraft. That is, a critical subset of the MISTE objectives could be obtained with a
dramatically reduced payload and mission concept. Ground-based observations of the neutral atmosphere