Abstract:
Embodiments of the present invention pertain to an apparatus that provides four simultaneous ion and neutral measurements as a function of altitude with variable sensitivity for neutral atmospheric species. The variable sensitivity makes it possible to extend the measurements over the altitude range of 100 to more than 700 kilometers. The four instruments included in the apparatus are a neutral wind-temperature spectrometer, an ion-drift ion-temperature spectrometer, a neutral mass spectrometer, and an ion mass spectrometer. The neutral wind-temperature spectrometer and ion-drift ion-temperature spectrometer are configured to separate O and N 2  and O+ from H+ while the neutral mass spectrometer and the ion mass spectrometer are configured to separate mass with a resolution of one in sixty-four to enable metallic ion identification in the lower thermosphere. The energy analyzer features of the wind-temperature spectrometer and ion-drift ion-temperature spectrometer also enable the measurement of the thermosphere-to-exosphere transition in the Earth&#39;s upper atmosphere.

Description:
ORIGIN OF THE INVENTION 
     The invention described herein was made by an employee of the United States Government and may be manufactured and used by or for the Government for Government purposes without the payment of any royalties thereon or therefore. 
    
    
     FIELD 
     The present invention relates to a wind ion neutral composition apparatus and, more particularly, to a wind ion neutral composition apparatus that includes a suite of spectrometers to facilitate measurements of atmospheric neutrals, neutral winds, neutral density, neutral temperature, neutral composition, ion density, ion composition, ion drift speeds, and ion temperatures. 
     BACKGROUND 
     Long-standing issues in the ionosphere-thermosphere include (1) thermosphere-to-exosphere transition, (2) the vertical variation of momentum balance as evidenced by neutrals and ion drifts, densities, and temperature, and (3) the true measure of the atomic oxygen density without internal ion source contamination. 
     SUMMARY 
     Certain embodiments of the present invention may provide solutions to the problems and needs in the art that have not yet been fully identified, appreciated, or solved by current analyzers. Embodiments described herein pertain to analyzers that provide energy-angle distribution of Maxwellian and non-Maxwellian ions and neutrals. With a mass spectrometer mounted on a high velocity payload (e.g., 4 km/s), some embodiments of the present invention can yield the following: 1-horizontal neutral wind, horizontal ion drift, 2-neutral and ion temperatures, and relative densities of major species (e.g., O/N2, H+/O+, ion and neutral composition up to 200 atomic mass units (amu) to include metallic neutrals and ions). 
     In one embodiment of the present invention, an apparatus is provided that includes a plurality of spectrometers, a plurality of micro-channel plates, and a plurality of anodes. Each spectrometer is configured to receive ions and neutrals. The plurality of micro-channel plates is configured to create a cloud of electrons as the ions exit the plurality of spectrometers. The plurality of anodes is configured to detect the cloud of electrons as the cloud of electrons exits the plurality of micro-channel plates. 
     In another embodiment of the present invention, a method includes receiving, at a plurality of spectrometers, ions and neutrals. The method also includes creating, by a plurality of micro-channel plates, a cloud of electrons as ions exit the plurality of spectrometers. The method further includes detecting, by a plurality of anodes, the cloud of electrons as the cloud of electrons exits the plurality of micro-channel plates. 
     In yet another embodiment of the present invention, an apparatus is provided that includes a plurality of spectrometers configured to receive ions and neutrals and a set of micro-channel plates, each operatively connected to one of the spectrometers. The apparatus also includes a plurality of anodes, each anode operatively connected to one of the micro-channel plates. The plurality of spectrometers includes a first spectrometer unit configured to receive the ions or neutrals, and a second spectrometer unit configured to receive the ions and neutrals simultaneously. The plurality of spectrometers also includes a third spectrometer unit orthogonal to the second spectrometer unit that is configured to receive the ions and neutrals simultaneously. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a proper understanding of the invention, reference should be made to the accompanying figures. These figures depict only some embodiments of the invention and are not limiting of the scope of the invention. Regarding the figures: 
         FIG. 1  illustrates a wind ion neutral composition suite (WINCS) apparatus, in accordance with an embodiment of the present invention. 
         FIG. 2  illustrates a WINCS apparatus with a field of view for each unit, in accordance with an embodiment of the present invention. 
         FIG. 3  illustrates internal components of a WINCS apparatus, in accordance with an embodiment of the present invention. 
         FIG. 4  illustrates a wind-temperature spectrometer/ion-drift ion-temperature spectrometer (WTS/IDTS) apparatus, in accordance with an embodiment of the present invention. 
         FIG. 5  illustrates a gated electro-static mass spectrometer (GEMS) apparatus, in accordance with an embodiment of the present invention. 
         FIG. 6  illustrates a WINCS apparatus, in accordance with an embodiment of the present invention. 
         FIG. 7  illustrates multiple micro-channel plates, in accordance with an embodiment of the present invention. 
         FIG. 8  illustrates a WINCS apparatus, in accordance with an embodiment of the present invention. 
         FIG. 9  illustrates a method for transmitting neutrals and particles through a WTS/IDTS unit, in accordance with an embodiment of the present invention. 
         FIG. 10  illustrates a method for transmitting ion particles through a GEMS unit, in accordance with an embodiment of the present invention. 
         FIG. 11  illustrates a method for transmitting neutral particles through a GEMS unit, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     It will be readily understood that the components of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of an apparatus, a system, a method, and a computer readable medium, as represented in the attached figures, is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. 
     The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of “certain embodiments,” “some embodiments,” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearances of the phrases “in certain embodiments,” “in some embodiments,” “in other embodiments,” or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     Many embodiments of the present invention pertain to a suite of spectrometers that have low size, weight and power to cover a large quantity of measures, such as atmospheric neutrals, neutral winds, neutral density, neutral temperature, ion density, ion composition, ion drift speeds, and ion temperatures, as well as any other measurements that would be appreciated by a person of ordinary skill in the art. 
       FIG. 1  illustrates a wind ion neutral composition suite (WINCS) apparatus  100 , in accordance with an embodiment of the present invention. In this embodiment, WINCS apparatus  100  is approximately 3 inches×3 inches×2.8 inches, but may have any desired dimensions, as would be appreciated by a person of ordinary skill in the art. The front face of WINCS apparatus  100  includes a plurality of spectrometers. For instance, WINCS apparatus  100  includes a gated electro-static mass spectrometer (GEMS)  105  and two neutral wind-temperature spectrometer (WTS)/ion-drift ion-temperature spectrometer (IDTS)  115 ,  130 . 
     GEMS  105  can be a combination of an ion mass spectrometer (IMS) and a neutral mass spectrometer (NMS) in some embodiments. GEMS (or a first unit)  105  includes a circular opening  110  that allows neutrals (or neutral particles) and ions to enter or flow into the spectrometer. WTS/IDTS (or a second unit)  115  includes vertical slits  120 ,  125  in order to receive ions and neutrals, and WTS/IDTS (or a third unit)  130  includes horizontal slits  135 ,  140  in order to receive ions and neutrals. 
     The top face of WINCS apparatus  100  includes an electrical connector  145 . Electrical connector  145  is configured to receive power from a spacecraft or aircraft in order to power WINCS apparatus  100 . Electrical connector  145  is also configured to transmit data to the spacecraft. 
       FIG. 2  illustrates a WINCS apparatus  200  with a field of view for each unit, in accordance with an embodiment of the present invention. As with  FIG. 1 , WINCS apparatus  200  includes a first unit  205 , a second unit  215 , and a third unit  230 . 
     First unit  205  includes a circular opening  210  that allows ions and/or neutrals to enter at an angle of 30 degrees. Because first unit  205  includes circular opening  210 , first unit  205  has a conical field of view and receives any neutrals and/or ions (i.e., particles) in the conical field of view. 
     Second unit  215  includes vertical slits  220 ,  225  that allow particles to enter at 30 degrees in a vertical direction and a few degrees in a horizontal direction. Third unit  230  is rotated 90 degrees (or orthogonal) to first unit  215  so that particles entering slits  235 ,  240  can enter at 30 degrees in a horizontal direction and a few degrees in the vertical direction. It should be appreciated that the 30 degrees for vertical slits  220 ,  225  and horizontal slits  235 ,  240  can be considered to be the field of view at which ions and neutrals can enter the units. It should be appreciated that the field of view allows measurements of incidence of the ions and neutrals coming along the vertical 30 degree angle for second unit  215  and the horizontal 30 degree angle for third unit  230 . 
       FIG. 3  illustrates internal components of WINCS apparatus  300 , in accordance with an embodiment of the present invention. WINCS apparatus  300  includes a first spectrometer unit (GEMS)  305  having a circular opening  310 , a second spectrometer unit (WTS/IDTS)  315  having vertical slits  320 ,  325 , a third spectrometer unit (WTS/IDTS)  330  having horizontal slits  335 ,  340 , an electrical connector  345 , a first power supply  350 , a housing  355 , an electronic stack  360 , and a second power supply  365 . 
     First unit  305  combines an ion mass spectrometer (IMS) and a neutral mass spectrometer (NMS) into a single spectrometer. Second unit  315  and third unit  330  allow for measurements of energy and angle, or wind-temperature O/N 2  ratio and ion drift-temperature density ratios (e.g., at low altitudes and high altitudes). Second unit  315  includes vertical slits  320 ,  325  for neutrals and ions, respectively. Third unit  330  includes horizontal slits  335 ,  340  for neutrals and ions, respectively. 
     Power supply  350  can be a high voltage power supply and is configured to power multiple micro-channel plates (see  FIGS. 5 and 6 ). For example, the high voltage from power supply  350  may be used to accelerate electrons through the micro-channel plates to allow an anode, which can be located behind the micro-channel plates, to detect a signal as the electrons exit the micro-channel plates. 
     Housing  355  includes a plurality of micro-channel plates (see  FIGS. 5 and 6 ), and is configured to sense ions and/or neutral particles as they flow out from the spectrometers. For instance, housing  355  includes a set of three micro-channel plates, one for each spectrometer unit (e.g., first unit  305 , second unit  315 , and third unit  330 ). By enclosing the micro-channel plates in housing  355 , extraneous light and/or photons are prevented from being picked up by the plates, facilitating a more accurate reading of measurements and analysis. 
     In this embodiment, electronic stack  360  includes three electronic plates. However, it should be appreciated that electronic stack  360  can include any number of electronic plates that would be appreciated by a person of ordinary skill in the art. Further, electronic stack  360  utilizes an anode for each unit or spectrometer that allows for a determination to be made as to the positioning of the ions and neutral particles, as well as the number of ions and neutral particles. This will be described in more detail below. 
       FIG. 4  illustrates a WTS/IDTS apparatus  400 , in accordance with an embodiment of the present invention. WTS/IDTS apparatus  400  includes slits (or apertures)  405 ,  410  for neutrals and ions. It should be appreciated that slits  405 ,  410  allow for simultaneous intake of both neutrals and ions, respectively. However, a person of ordinary skill in the art will appreciate that WTS/IDTS apparatus  400  can be configured to receive ions and neutrals independently. 
     WTS/IDTS apparatus  400  also includes an ionization region  415  that includes a thermionic cathode. The thermionic cathode is configured to transmit a beam across the path of the neutrals in order to strip an electron off of the neutral. This converts the neutral atoms into an ionized particle prior to entering chamber  430  described below. 
     WTS/IDTS apparatus  400  also includes two small deflection energy analyzers (SDEAs)  420 ,  425 . The space between SDEAs  420 ,  425  can be considered as chamber  430 . By applying voltage to SDEA  425 , an electric field is created in chamber  430  to cause ions to pass through chamber  430  and exit through apertures  435 ,  440 . Chamber  430  can be interpreted by a person of ordinary skill in the art to include two chambers separated by a common wall of the two side-by-side SDEAs  420 . Left chamber L can be for ionized neutral particles and the right chamber R can be for ions. 
     In order to create the electric field to deflect the ions passing through the chamber, two different levels of voltage are applied to SDEAs  420 ,  425 . For instance, SDEA  420  is grounded, or set to zero volts, and SDEA  425  is set to a higher voltage depending on the deflection path. Based on the voltage applied to SDEA  425 , ions from slit  410  can enter right chamber R and exit through aperture  440  and then enter the micro-channel plates via aperture  445 . Neutrals, for example, that enter slit  405  are ionized by the thermionic cathode and then enter left chamber L. The ionized particles exit chamber  430  through aperture  435  based on the voltage applied to SDEA  425  and then enter the micro-channel plates via aperture  450 . In other words, the two halves of WTS/IDTS apparatus  400  are for sensing ions in one half and ionized neutral particles in the other half. 
     Further, WTS/IDTS apparatus  400  is configured to measure the angular distribution and the energy distribution as the ions and neutrals enter. Angular distribution is defined by the size of the slit. Energy distribution is measured by changing the electro-static field within WTS/IDTS APPARATUS  400  to allow different energies to pass through the exit aperture. By analyzing the combination, the neutral winds and neutral temperature can be measured by looking at the width of the energy, the ion drifts, the ion temperature, and the ion and neutral densities. 
     For angular measurements, the geometry of slits  405 ,  410 , as well as the angle at which the particles entered slits  405 ,  410  are considered. For instance, a particle will enter the system through slits  405 ,  410  at a certain angle and then pass through the system and collide with the anode situated on the electronic circuit board. Depending on the angle at which the particle enters the system, the particle will collide with one of the anodes on the strip of anodes. And, based on which anode the particle collides, a determination is made as to the angle at which the particle entered the system. 
     Energy is analyzed by changing the electronic field through which the ions pass. For example, as the voltage is being ramped up, energy of particles that pass through the exit slit of the SDEA is also being ramped up. This allows for an energy analysis to be conducted. For instance, when voltage is applied to a surface of SDEA  425 , an electric field is created. As a result, any charged particle that flows through the electric field is affected. In other words, by changing the strength of the electric field, the flow of the particles is changed accordingly. For example, when the voltage is increased, the movement of the lower energy particles and higher energy particles is changed, such that lower energy particles move more swiftly than the higher energy particles. This allows for control of which particles (lower energy or higher energy) pass through the exit slit. 
       FIG. 5  illustrates a GEMS apparatus  500 , in accordance with an embodiment of the present invention. GEMS apparatus  500  allows for measurements of atmospheric composition both for neutrals and ions, and uses time of flight mass spectrometry (i.e., measuring the time it takes for the particles to pass from a certain gate until the particles reach the anode) and, based on the time, the mass of the particle is determined. 
     GEMS apparatus  500  includes, amongst other things, a grid (or deflection lens)  505 , a thermionic cathode  510 , a gate system having a left (first) block  515  and a right (second) block  520 , a SDEA  535  and  540 , and exit apertures  545 ,  550 ,  555 . In this embodiment, because GEMS apparatus  500  does not allow for neutrals and ions to enter simultaneously, GEMS apparatus  500  is configured to switch between acceptance of neutrals and ions. In order to switch between ions and neutrals, grid  505  is situated such that all ions and/or neutrals entering apparatus  500  pass through grid  505 . For instance, when a positive voltage is applied to grid  505 , neutrals can enter apparatus  500  and can be analyzed. The positive voltage prevents ions from entering apparatus  500  at the same time as the neutrals. In other words, when the grid  505  is activated, ions are repelled and thus prevented from entering GEMS apparatus  500 . However, when zero volts are applied to grid  505 , or in other words when grid  505  is deactivated, neutrals are prevented from entering GEMS apparatus  500  and ions are allowed to enter GEMS apparatus  500  and then are analyzed accordingly. 
     When sensing neutrals, GEMS apparatus  500  utilizes cathode  510  to strip off an electron to convert the neutral into an ion prior to entering the electric field. For instance, cathode  510  transmits a beam of electrons horizontally and hits the neutral to convert the neutral into an ionized particle. 
     As discussed above, in this embodiment, the gate system includes two blocks; right block  520  having a square wave voltage from 0 to 5 volts and left block  515  being grounded or at 0 volts. However, the voltage is variable, and may exceed this range, subject to design choice. For example, when right block  520  is set to 5 volts, right block  520  prevents any ions from passing through the gate system by deflecting the ions into left block  515 . However, when right block  520  is set to 0 volts, ions are able to pass through the gate system and through electric field  530 , which is created by SDEAs  535 ,  540 . 
     As ions pass through the gate system, different voltages (e.g., −1000 volts and −1200 volts) are applied to SDEAs  535 ,  540  causing an electric field  530  to be created. Electric field  530  allows ions (or particles) to pass through electric field  530  and exit through apertures  545 ,  550 ,  555 . After exiting through apertures  545 ,  550 ,  555 , ions collide with micro-channel plates to form a cloud of electrons. It should be appreciated that the use of multiple apertures reduces the amount of scattered light. 
     GEMS apparatus  500  allows for measurements to be taken of the time from when the gate was opened until the particle reached the anode. For example, by setting the voltage of right block  520  of gate system  515  to 0 volts, a measurement is conducted of the time it took for particles of different masses to go from the beginning of gate system  520  to the anode. Based on the differences in the times, a determination can be made as to the type of composition the particle was, i.e., whether the particle is Nitrogen, Oxygen, etc. 
       FIG. 6  illustrates WINCS apparatus  600 , in accordance with an embodiment of the present invention. In particular,  FIG. 6  illustrates housing  605  that interfaces between GEMS and micro-channel plates  610 , the two WTS/IDTS units and micro-channel plates  615 ,  620 . As ions are colliding with micro-channel plates, if stray light were to hit micro-channel plates as well, then additional electrons would be created causing an increased background level in measurements. To prevent the disruption of measurements, housing  605  is utilized to prevent photons or light from reaching the micro-channel plates, because micro-channel plates are sensitive to photons, light, and particles such as oxygen and nitrogen. 
       FIG. 7  illustrates a set of micro-channel plates  700 , in accordance with an embodiment of the present invention. In the WINCS apparatus described in the figures above, there is a set of three micro-channel plates, one for the GEMS unit and one for each WTS/IDTS unit. It should be appreciated that the set of micro-channel plates can be more or less than three depending on the number of spectrometers used, and/or the design choice. In this embodiment, the each set of three micro-channel plates includes two micro-channel plates (or glass plates)  705 ,  710  stacked up against each other. Each plate includes voltage connectors  715 ,  720 , respectively, in order to receive power from the power supply. 
     When ions or neutrals collide with the top of plate  705 , an electron is knocked off and the electron is accelerated through micro-channel plates  705 ,  710  by the voltage difference on the plates driven by the high voltage power supply. In order for the electrons to flow through plates  705 ,  710 , the voltage for plate  705  may be set to −2700 volts via connector  715  and voltage for plate  710  may be set to −500 volts via connector  720 . However, it should be appreciated that the voltages used are a matter of design choice. As the electron rattles through the glass pores of plates  705 ,  710 , additional electrons are knocked off to generate a cloud of electrons. When the cloud of electrons collides with the anode (not shown), creating an electrical signal to conduct measurements. 
       FIG. 8  illustrates a WINCS apparatus  800 , in accordance with an embodiment of the present invention. In this embodiment, WINCS apparatus  800  includes an electronic stack  805  that includes electronic plates  810 ,  815 ,  820 ,  825 . 
     Electronic plate  810  includes a plurality of anodes. In this embodiment, electronic plate  810  includes three sets of anodes  830 ,  835 ,  840 , one for each instrument, i.e., the GEMS unit and the two WTS/IDTS units. Anodes  835  and  840  include 16 anodes in each strip, but may be any number that will be appreciated by a person of ordinary skilled in the art. It should be appreciated that the direction of the strip is based on the slit position in the WTS/IDTS unit. 
     In this embodiment, electronic stack  805  is configured to sense a cloud of electrons exiting the micro-channel plates described above via anodes  830 ,  835 ,  840 . For instance, electronic stack  805  senses the cloud of electrons colliding with each anode from the respective micro-channel plates and processes the charge sensed by anodes  830 ,  835 ,  840 . 
     For instance, when the charge is sensed on the anodes  830 ,  835 ,  840 , the set of electronics for the WTS/IDTS unit is configured to setup a counter for a certain integration period and determines whether a count is detected on a particular anode. When an event occurs (that is, when ionized particles or ions collide with an anode), the event is registered on the anode, and watches for what the integration period was set to. The electronics also accumulates for a certain amount of time and, once the time is over, the electronics transmit that number to the other electronics, which processes the number. The number then gets transmitted to the spacecraft via connector. 
     For the GEMS unit, a counter is setup for a period of time. During the period of time, the number of events is registered as a function of time. Based on the number of events registered during the period of time, a determination is made as to the type of mass that caused the events. For example, electronic stack  805  also outputs how many events were accumulated on the integration period of each anode and, for the GEMS unit, it would be a set of timing pulses that allows for a determination to be made as to the type of the mass of the particle. 
       FIG. 8  also shows an electrical connector  845  situated between electronic plates  810  and  815 . Electrical connector  845  receives power from the spacecraft or aircraft, as well as transmits data to the spacecraft or aircraft. Electronic plate  810  is also connected to a power supply  850  and electronic plate  825  is connected to another power supply  855 . Power supplies  850 ,  855  may be high voltage power supplies. As discussed above, power supply  850  provides power to micro-channel plates in order to drive electrons through the micro-channel plates. Power supply  855  controls the voltages on the SDEAs in the WTS/IDTS units and the GEMS unit in order for the ions to pass through the respective units. 
       FIG. 9  illustrates a method  900  for transmitting neutrals and particles through a WTS/IDTS unit, in accordance with an embodiment of the present invention. At  905 , neutrals and ions enter the unit through a slit for neutrals and another slit for ions. At  910 , neutrals are converted into ionized particles by utilizing a thermionic cathode. At  915 , an electric field is created by applying  0  volts on the first SDEA and applying a higher voltage on the second SDEA. The electric field at  920  deflects the ions and ionized particles to exit through the exit apertures. 
       FIG. 10  illustrates a method  1000  for transmitting ion particles through the GEMS unit, in accordance with an embodiment of the present invention. At  1005 , the voltage on the deflection lens is set to 0 or the lens is deactivated in order for the ions to enter the GEMS unit. At  1010 , a voltage is applied to the gate system, preventing the ions from entering the electric field. At  1015 , the voltage is reduced or not applied to cause the ions to pass through the electric field. At  1020 , ions are deflected, causing them to exit through the exit apertures of the GEMS unit by applying different voltages to the SDEAs. 
       FIG. 11  is a method  1100  for transmitting neutrals through the GEMS unit, in accordance with an embodiment of the present invention. At  1105 , the voltage on the deflection lens is set to a higher voltage in order to prevent ions from entering the GEMS unit and to allow neutrals to enter the GEMS unit. At  1110 , neutrals entering the GEMS unit are converted into ionized particles by using a thermionic cathode. At  1115 , a voltage is applied to the gate system preventing the ionized particles from entering the electric field. At  1120 , when the voltage is reduced or not applied, the ionized particles are allowed to pass to the electric field. At  1025 , different voltages are applied to the SDEAs in order to deflect the ionized particles through the electric field, causing them to exit apertures of the GEMS unit. 
     The method steps performed in  FIGS. 9 to 11  can be performed by a computer program, encoding instructions for a nonlinear adaptive processor to perform at least the methods described in  FIGS. 9 to 11 , in accordance with an embodiment of the present invention. The computer program may be embodied on a non-transitory computer readable medium. A computer readable medium may be, but is not limited to, a hard disk drive, a flash device, a random access memory, a tape, or any other such medium used to store data. The computer program may include encoded instructions for controlling the nonlinear adaptive processor to implement the method described in  FIGS. 9 to 11 , which may also be stored on the computer readable medium. 
     The computer program can be implemented in hardware, software, or a hybrid implementation. The computer program can be composed of modules that are in operative communication with one another, and which are designed to pass information or instructions to display. The computer program can be configured to operate on a general purpose computer, or an application specific integrated circuit (“ASIC”). 
     One or more embodiments of the present invention pertain to an apparatus having a suite of spectrometers. The suite includes energy-angle spectrometers, i.e., a neutral wind-temperature spectrometer (WTS) and an ion-drift ion-temperature spectrometer (IDTS). The WTS can be utilized for wind-temperature —O/N 2  ratio and the IDTS can be utilized for ion drift-temperature-density ratios (e.g., at low altitudes and at high altitudes). The suite also includes a mass analyzer that allows two spectrometers to be combined into a single rectangular package, one half for an ion mass spectrometer (IMS) and the other half for a neutral mass spectrometer (NMS). The high payload velocity enables measurement of non-Maxwellian energy distributions and also the separation of O (oxygen) from internal ion source products. 
     The embodiments described above allow for variable sensitivity for neutral atmospheric species. The variable sensitivity makes it possible to extend the measurements over the altitude range of 100 km to more than 700 km. This capability will make it possible to study the coupling of multiple atmospheric regions at once, addressing questions of energy, momentum, and mass transfer from one region to another. For example, reflection and transmission of atmospheric waves between E and F regions of the ionosphere; or between the mesosphere and the thermosphere; or between the thermosphere and the exosphere. Also, the embodiments allow for high velocity coupled with the energy analyzer to provide a true measurement of the atomic oxygen density without the previous issues of internal ion source contamination. 
     One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations, which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.