CubeSat Radiometer Radio Frequency Interference Technology Validation (CubeRRT) - 10.04.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Microwave radiometers provide important data for Earth science investigations, such as soil moisture, atmospheric water vapor, sea surface temperature and sea surface winds. Man-made radiofrequency interference (RFI) reduces the accuracy of microwave radiometer data, thus the CubeSat Radiometer Radio Frequency Interference Technology Validation (CubeRRT) mission demonstrates technologies to detect and remove these unwanted RFI signals. Successful completion of the CubeRRT mission demonstrates that RFI processing is feasible in space, high volumes of data may be processed aboard a satellite, and that future satellite-based radiometers may utilize RFI mitigation.
Science Results for Everyone
Information Pending

The following content was provided by Joel Johnson, Ph.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom:

Principal Investigator(s)
Joel Johnson, Ph.D., The Ohio State University, Columbus, OH, United States

Co-Investigator(s)/Collaborator(s)
Damon Bradley, Ph.D., NASA Goddard Space Flight Center, Greenbelt, MD, United States
Shannon Brown, Ph.D., NASA Jet Propulsion Laboratory, Pasadena, CA, United States
Chi-Chih Chen, Ph.D., The Ohio State University, Columbus, OH, United States
Robert Jarnot, Ph.D., NASA Jet Propulsion Laboratory, Pasadena, CA, United States
Jonathan Kocz, Ph.D., California Institute of Technology, Pasadena, CA, United States
Jared Lucey, M.S.E.E., NASA Goddard Space Flight Center, Greenbelt, MD, United States
Sidharth Misra, Ph.D., NASA Jet Propulsion Laboratory, Pasadena, CA, United States
Priscilla Mohammed, Ph.D., NASA Goddard Space Flight Center, Greenbelt, MD, United States
Jeffrey Piepmeier, Ph.D., NASA Goddard Space Flight Center, Greenbelt, MD, United States

Developer(s)
The Ohio State University, Columbus, OH, United States
NASA Goddard Space Flight Center, Greenbelt, MD, United States
NASA Jet Propulsion Laboratory, Pasadena, CA, United States
Blue Canyon Technologies, Boulder, CO, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Technology Demonstration Office (TDO)

Research Benefits
Information Pending

ISS Expedition Duration
February 2018 - October 2018

Expeditions Assigned
55/56

Previous Missions
Information Pending

^ back to top

Experiment Description

Research Overview

  • Recent microwave radiometry measurements below 40 GHz have exhibited increasing levels of radiofrequency interference (RFI).
  • This measured RFI may corrupt geophysical retrievals in a variety of crucial science products, including soil moisture, atmospheric water vapor, sea surface temperature, sea surface winds, and many others.
  • The increase in RFI is because the spectrum available for commercial use is becoming increasingly crowded, accelerating demand to open the bands reserved for passive microwave Earth observation and radio astronomy applications to general use.
  • Initial progress in RFI mitigation technologies for microwave radiometry in space has been achieved by the Soil Moisture Active Passive (SMAP) mission. RFI detection and mitigation for SMAP is performed on the ground following downlink of the radiometer data. However, future radiometer systems operating over the 6-40 GHz range produce a volume of data that is too high to allow downlink to earth for subsequent RFI processing. As a result, real-time, onboard RFI processing is critical for future radiometry missions.
  • CubeSat Radiometer Radio Frequency Interference Technology Validation (CubeRRT) demonstrates a satellite-based, real-time RFI processing capability from 6 to 40 GHz.
  • The mission matures the onboard RFI processing capability from Technology Readiness Level (TRL) 5 to TRL 7 (demonstration in a space environment).
  • The successful completion of the CubeRRT mission verifies that: onboard RFI processing is feasible in space; high volumes of data may be process aboard a satellite; and future satellite-based radiometers may employ onboard RFI mitigation.

Description

The CubeSat Radiometer Radio Frequency Interference Technology Validation (CubeRRT) radiometer acquires wideband measurements in 10 distinct frequency bands. These pre-defined bands correlate with primary and secondary allocations in the range of 6 GHz to 40 GHz and are relevant to passive microwave remote sensing. The radiofrequency interference (RFI) mitigation technology is demonstrated on flight-ready hardware in the laboratory to advance to Technology Readiness Level (TRL) 6 prior to launch and then on a spaceborne 6U CubeSat platform to advance from TRL 6 to 7. The primary objective of the CubeRRT mission is to demonstrate operation of the wideband digital RFI mitigation technology, enabling detection and removal of pulsed and continuous sinusoidal RFI with a power level more than twice the noise equivalent delta temperature (NEDT) for a 1GHz Nyquist bandwidth. The baseline CubeRRT mission provides radiometry data from at least 100 hours of spaceborne operation, including at least 10 hours of spaceborne operation in each of 10 predefined radiometry bands.
 
The CubeRRT 6U spacecraft bus is designed, constructed, and tested by Blue Canyon Technologies (BCT). Key features of the spacecraft include the bus power system (solar panels, batteries), an isolated power supply for the radiometer payload, data communications systems (Cadet radio and Globalstar satellite communications), the mechanical frame and other avionics components. BCT oversees payload integration and testing, including performance, operation, and environmental tests prior to delivery for launch.
 
CubeRRT consists of 3 subsystems: a tunable analog radiometer front-end (RFE), a radiometer digital backend (RDB) that performs real-time RFI mitigation, and a set of wideband tapered helical antennas. The tunable analog RFE subsystem is developed by NASA Goddard Space Flight Center (GSFC). The RFE covers 6 to 40 GHz with a single tunable superheterodyne receiver and internal calibration. The RDB subsystem is developed by NASA Jet Propulsion Laboratory (JPL). The RDB consists of 2 main components: an analog-to-digital converter (ADC) capable of digitizing a 1 GHz bandwidth, and a field programmable gate array (FPGA) for RFI processing. The radiometer antenna subsystem is designed and tested at The Ohio State University to provide a gain ranging from 12 dBi (at 6 GHz) to 21 dBi (at 40 GHz) in a circular polarization. A series of 3 tapered helical antennas provide the necessary gain, with each antenna covering specific portions of the 6 to 40 GHz bandwidth. The antenna subsystem includes a custom-built radome to optimize antenna gain and is deployed from a stowed configuration once in orbit. CubeRRT’s mission goals of evaluating onboard RFI mitigation is complicated by limited solar cell and battery capacity of the 6U CubeSat, leading to unique challenges for payload operations. These challenges primarily reside with regard to scheduling power cycling and frequency tuning of the payload. In contrast to other radiometer missions, which typically aim to gather brightness temperature information of the entire Earth’s surface, CubeRRT’s power budget allows operation only at a duty cycle of approximately 30%. The system prioritizes operation over coordinates of known RFI sources and over landmasses where RFI is more likely to occur.

^ back to top

Applications

Space Applications
Successful completion of the CubeRRT mission enables future deployment of RFI mitigation technology aboard satellites that employ high frequency and high bandwidth microwave radiometers. The technology also enables these radiometers to work outside of primary or secondary frequency allocations, covering a broader range of operational frequencies and co-existing with earth-based communications systems, radar systems, and other potential sources of RFI.

Earth Applications
Successful completion of the CubeRRT mission increases the accuracy of Earth science data products obtained by spaceborne microwave radiometers, including soil moisture, atmospheric water vapor, sea surface temperature, sea surface winds, and many others.

^ back to top

Operations

Operational Requirements and Protocols

NanoRacks CubeSats are delivered to the International Space Station (ISS) already integrated within a NanoRacks CubeSat Deployer (NRCSD) or NanoRacks DoubleWide Deployer (NRDD). A crew member transfers each NRCSD/NRDD from the launch vehicle to the Japanese Experiment Module (JEM). Visual inspection for damage to each NRCSD is performed. When CubeSat deployment operations begin, the NRCSD/NRDDs are unpacked, mounted on the JAXA Multi-Purpose Experiment Platform (MPEP) and placed on the JEM airlock slide table for transfer outside the ISS. A crew member operates the JEM Remote Manipulating System (JRMS) – to grapple and position for deployment. CubeSats are deployed when JAXA ground controllers command a specific NRCSD.
 
CubeRRT operations are commanded based on a scheduler simulation tool developed by The Ohio State University (OSU). This tool may be used to develop algorithms for power cycling and frequency tuning, which propagates over the orbital lifetime to predict and optimize CubeRRT measurement results. The scheduler provides information such as the duration until mission-level requirements are fulfilled, radiometry coverage maps, long-term battery depth-of-discharge (DOD), and payload data. In addition, the scheduler may be used to automate the process of generating payload command sequences uplinked regularly to the spacecraft during operations. To properly model CubeRRT’s operations, the scheduler simulates the power system, telemetry, RFI coordinates, and orbital propagation models. The power system state is modelled with knowledge of the available energy from CubeRRT’s solar cells, the known power draw from the satellite bus and payload subsystems, and the battery capacity. Telemetry and payload data buffers are monitored and downlinked at a known rate to the Wallops Flight Facility to predict and prevent buffer overflow conditions.

^ back to top

Decadal Survey Recommendations

Information Pending

^ back to top

Results/More Information

Information Pending

^ back to top

Related Websites

^ back to top


Imagery

image NASA Image: ISS056E033124 - Expedition 56 Flight Engineer Serena Auñón-Chancellor installs the NanoRacks Cubesat Deployer-14 (NRCSD-14) on the Multipurpose Experiment Platform inside the Japanese Kibo laboratory module. The NRCSD-14 was then placed in the Kibo airlock and moved outside of the space station to deploy a variety of cubesats into Earth orbit.
+ View Larger Image


image NASA Image: ISS056e033126 - Expedition 56 Flight Engineer Serena Auñón-Chancellor installs the NanoRacks Cubesat Deployer-14 (NRCSD-14) on the Multipurpose Experiment Platform inside the Japanese Kibo laboratory module. The NRCSD-14 was then placed in the Kibo airlock and moved outside of the space station to deploy a variety of cubesats into Earth orbit.
+ View Larger Image


image NASA Image: ISS056E033143 - A view during installation of the NanoRacks Cubesat Deployer-14 (NRCSD-14) on the Multipurpose Experiment Platform inside the Japanese Kibo laboratory module. The NRCSD-14 was then placed in the Kibo airlock and moved outside of the space station to deploy a variety of cubesats into Earth orbit.
+ View Larger Image