| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
|
| Initial Amendment Date: | September 28, 2011 |
| Latest Amendment Date: | September 28, 2011 |
| Award Number: | 1042780 |
| Award Instrument: | Standard Grant |
| Program Manager: |
John Meriwether
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | October 1, 2011 |
| End Date: | September 30, 2016 (Estimated) |
| Total Intended Award Amount: | $72,000.00 |
| Total Awarded Amount to Date: | $72,000.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
21 N PARK ST STE 6301 MADISON WI US 53715-1218 (608)262-3822 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
21 N PARK ST STE 6301 MADISON WI US 53715-1218 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | AGS-ATM & Geospace Sciences |
| Primary Program Source: |
|
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
This project is for a 3U CubeSat mission named EXOCUBE to measure the densities of all significant neutral and ionized species in the upper atmosphere on a global scale. The project will provide the first in-situ global neutral density data in more than 25 years, including the first direct measurements of Hydrogen densities using the mass spectrometer technique. An important science objective for EXOCUBE is to provide observational constraints for physical models of the upper atmosphere. Additionally, the measurements will be used to test and validate newly developed experimental techniques to obtain neutral and ionized composition and densities from radar and optical observations. The EXOCUBE measurements will also be used for several immediate science investigations. Specific science questions to be addressed include: 1) the inter-hemispheric transport of Hydrogen and protons in the quiescent and storm-time exosphere, and 2) characterization of neutral atmospheric drivers in response to magnetic storms. Data for each of four neutral and ion species (O, He, H, N2, O+, He+, H+, and NO+) are gathered by a set of two Static Energy Angle Analyzers, one for Neutrals (NSEAA) and one for Ions (ISEAA), respectively. The instrument is a new design that has been developed recently through a collaboration between NASA and the Naval Research Laboratory. A third instrument, a Faraday cup, is included for calibration, reducing ion density uncertainties to approximately plus or minus 3%. The satellite will collect data in two modes. In 'patrol mode' the measurements will be made approximately every degree of longitude and in 'coordinated experimental mode' the measurements will be made every tenth of a longitude degree in conjunction with ground based radar and optical measurements. The satellite is to be launched into low Earth orbit with an inclination of greater than or equal to 45 degrees, passing over three current radar sites, and at least six optical Aeronomy sites.
The EXOCUBE project is a collaboration between Scientific Solutions Inc. (SSI), California Polytechnic State University (Cal Poly), and The University of Wisconsin (UW). Also partnering in the effort are NASA Goddard Space Flight Center, and SRI International. In addition, the project coordinates with existing NSF radar facilities and optical sites for targeted experiments during the satellite lifetime. The EXOCUBE dataset has broad utility, leading to long-awaited improvements in a wide range of physical and semi-empirical composition models for the upper atmosphere and to verification of radar and optical measurement techniques providing composition data. As such, the project will provide the foundation for a very large and diverse set of further aeronomy and space weather science investigations. Particularly, reliable knowledge of exospheric Hydrogen distribution is a crucial requirement for realistically modeling Total Electron Content, which is currently a very high priority space weather objective. Educational impacts of the project are extraordinary. The satellite bus and operating systems are designed and built by 20-40 students in the laboratories at Cal Poly, and payload integration is also performed by students at Cal Poly. Students at the University of Wisconsin are involved with instrument calibration and testing and with initial assessment of data integrity. Data formatting and archiving are also student led.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Scientists are studying the upper atmosphere to gain understanding of the vertical structure of the atmosphere and its variability as well as interactions between the atmosphere and near-space environment. The ExoCube mission was designed to contribute to this effort by acquiring global knowledge of the densities of key neutral and ion atoms in the lower exospheric region of the atmosphere. ExoCube is one of the National Science Foundation’s Cubesats and is a small satellite of dimensions 10 cm x 10cm x 30 cm. The project is a collaboration between scientists and engineers at Scientific Solutions Inc. (Principal Investigator John Noto), NASA Goddard (instrument design), Cal Poly (satellite design) and the science team at Scientific Solutions Inc., the University of Illinois, the University of Wisconsin, and Embry-Riddle Aeronautics University.
The NASA Goddard team designed and built the Gated Time-of-Flight Mass Spectrometer instrument on board ExoCube. This instrument was designed to make in situ measurements (at the satellite location) of neutral atomic oxygen, atomic hydrogen, atomic helium; and singly ionized O+, H+, and He+ densities. Atomic oxygen and helium have not been measured in situ since the early 1980s during the era of the Dynamics Explorer and then only for 18 months, and atomic hydrogen has never been directly measured in situ in this region.
A key goal of the mission was to make the first direct measurements of atomic hydrogen (H)in the lower exosphere. Atomic hydrogen in the top-most regions of the Earth’s atmosphere (thermosphere and exosphere) is produced by chemical and physical processes lower in the atmosphere that involve methane and water vapor, two molecules important to the energy balance of the Earth’s atmosphere, as well as other molecules containing hydrogen. Charge exchange reactions with ions also produce atomic hydrogen. At the top of the atmosphere, the atoms are so far apart that they can travel for thousands of kilometers before colliding with another atom, creating a unique region of orbiting particles traveling along long trajectories. This region is strongly influenced by the sun and its space weather, including changes in the high-energy ultraviolet part of the sun’s energy over the 11-year natural cycle of the sun.
Key scientific objectives of the ExoCube mission include investigation of upper atmospheric global, day-night, and seasonal variability in the upper atmosphere; interactions between neutral atoms and ions, atmospheric response to geomagnetic storms; and the retrieval of densities at different altitudes by using the Exocube in situ measurements in conjunction with observations by instruments at ground observatories. Another goal was to use the ExoCube measurements to compare with upper atmospheric models.
ExoCube was successfully launched and deployed on January 31st, 2015 with the NASA Soil Moisture Active Passive Satellite. Unfortunately, the ExoCube antenna did not deploy properly after the launch and the transmitted signal was weak. There was sufficient signal to send commands to the satellite and to transmit a small amount of data to ground receiving stations. The initial testing and on-flight data indicated encouraging performance of the instrument. Later in the summer when the satellite was pointed into the proper orientation the satellite lost all contact with ground stations.
While ExoCube was not able to transmit science data the mission provided encouraging results from the instrument and training and experience that would be useful for future missions. A team of undergraduate and graduate students at Cal Poly had the opportunity to learn while building the satellite and a Ph.D. student at the University of Wisconsin was a key member of the science team. An expert panel reviewed the engineering to understand the problems with the antenna and suggest alternative strategies. The instrument, science, and engineering teams have gained experience that can be applied to future flights of similar instuments.
Last Modified: 11/20/2016
Modified by: Susan M Nossal
Please report errors in award information by writing to: awardsearch@nsf.gov.
