Meteoroid Impact Detection for Exploration of Asteroids (MIDEA): A Small Satellite Concept for Asteroid Characterization

2017 ◽  
Author(s):  
Nicolas Lee ◽  
Sigrid Close
Keyword(s):  
Small Satellite ◽  
Impact Detection ◽  
Meteoroid Impact

scholarly journals Design of a high-stability heterogeneous clock system for small satellites in LEO

GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Damon Van Buren ◽  
Penina Axelrad ◽  
Scott Palo
Keyword(s):  
Low Power ◽  
High Stability ◽  
Time Frame ◽  
System Stability ◽  
Small Satellite ◽  
Crystal Oscillator ◽  
Small Satellites ◽  
Clock System ◽  
Wide Range

AbstractWe describe our investigation into the performance of low-power heterogeneous timing systems for small satellites, using real GPS observables from the GRACE Follow-On mission. Small satellites have become capable platforms for a wide range of commercial, scientific and defense missions, but they are still unable to meet the needs of missions that require precise timing, on the order of a few nanoseconds. Improved low-power onboard clocks would make small satellites a viable option for even more missions, enabling radio aperture interferometry, improved radio occultation measurements, high altitude GPS navigation, and GPS augmentation missions, among others. One approach for providing improved small satellite timekeeping is to combine a heterogeneous group of oscillators, each of which provides the best stability over a different time frame. A hardware architecture that uses a single-crystal oscillator, one or more Chip Scale Atomic Clocks (CSACs) and the reference time from a GPS receiver is presented. The clocks each contribute stability over a subset of timeframes, resulting in excellent overall system stability for timeframes ranging from less than a second to several days. A Kalman filter is used to estimate the long-term errors of the CSACs based on the CSAC-GPS time difference, and the improved CSAC time is used to discipline the crystal oscillator, which provides the high-stability reference clock for the small satellite. Simulations using GRACE-FO observations show time error standard deviations for the system range from 2.3 ns down to 1.3 ns for the clock system, depending on how many CSACs are used. The results provide insight into the timing performance which could be achieved on small LEO spacecraft by a low power timing system.

scholarly journals SARS-CoV-2 N gene mutations impact detection by clinical molecular diagnostics: Reports in two cities in the United States

2021 ◽  
pp. 115468
Author(s):  
Mindy Leelawong ◽  
Stephanie L. Mitchell ◽  
Randal C. Fowler ◽  
Scott Hughes ◽  
Marissa P. Griffith ◽  
...  
Keyword(s):  
United States ◽  
Molecular Diagnostics ◽  
Gene Mutations ◽  
The United States ◽  
N Gene ◽  
Impact Detection ◽  
Two Cities

Development and flight qualification of a small satellite X-band spherical membrane antenna

2021 ◽  
Author(s):  
Aman Chandra ◽  
Terrance Pat ◽  
Juan Carlos Lopez Tonazzi ◽  
Christopher K. Walker
Keyword(s):  
Small Satellite ◽  
X Band
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