Project Selections for InVEST-17

07/05/2018 – NASA’s Science Mission Directorate, NASA Headquarters, Washington, DC, has selected proposals for the In-Space Validation of Earth Science Technologies Program in support of the Earth Science Division (ESD). The space environment imposes stringent conditions on components and systems, some of which cannot be fully tested on the ground or in airborne systems. Because of the harsh conditions, there has been, and continues to be, a need for new technologies to be validated in space prior to use in a science mission. The In-Space Validation of Earth Science Technologies (InVEST) program element is intended to fill that gap.

This InVEST solicitation was targeted to small instruments and instrument subsystems that can advance technology to enable relevant Earth science measurements. The call was limited to in-space validation only, and targeted to the CubeSat platform. From a total of 25 proposals received, the ESD has selected four proposals. The total first-year funding for these investigations is approximately four million dollars.

The awards are as follows (click on the name to go directly to the project abstract):

James Garrison, Purdue University SNOOPI: SigNals-Of-Opportunity P-band Investigation

Robert Wright, University of Hawaii, Honolulu Hyperspectral Thermal Imager (HyTI)

David Harber, University Of Colorado, Boulder Compact Total Irradiance Monitor Flight Demonstration

Steven Love, Los Alamos National Security, LLC Compact high-resolution trace-gas hyperspectral imagers, with agile on-board processing

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James Garrison, Purdue University
SNOOPI: SigNals-Of-Opportunity P-band Investigation

SigNals of Opportunity: P-band Investigation (SNoOPI) will be the first on-orbit demonstration of P-band (240-380 MHz) signals of opportunity (SoOp). SNoOPI will demonstrate an innovative instrument that shows promise for measuring root-zone soil moisture (RZSM) and snow water equivalent (SWE) from space. Accurate measurement of RZSM, identified as a priority target variable for technology development initiatives in ESAS 2017, is of national importance and critical to food production. Microwave observations at P-band are needed to penetrate into the root zone. Snow provides freshwater during spring and summer for a large portion of the world and plays a critical role in hydrology and water management. SoOp measurements of phase-delay are proportional to SWE, whose measurement was recommended as a program element in ESAS 2017.

Conventional P-band radar and radiometers are prone to RF spectrum access problems and require very large antennas to obtain sufficient signal-to-noise ratio or spatial resolution. SoOp reuses signals from existing telecommunications satellites and thus does not require a transmitter, as compared to a radar. Such signal efficiency makes SoOp very cost effective.

The objective of SNoOPI is in-space validation of the P-band SoOp technique and a prototype instrument. This is a necessary risk reduction step on the path to a science mission and will verify important assumptions about reflected signal coherence, robustness to the RFI environment, and our ability to capture and process the transmitted signal in space.

Our baseline mission design is driven by this objective, which will be met through demonstrating measurement of the complex reflection coefficient over various land surface conditions and showing that statistics of the reflection coefficient magnitude and phase retrieval meet the working requirements for a future RZSM and SWE mission.

We are entering the InVEST program with a TRL5 technique and instrument and building upon our team’s success on several competitively selected and internally funded projects. Our instrument consists of three subsystems: 1) The low noise front end (LNFE), developed from the SoOp-AD (IIP-13) airborne demonstration instrument and redesigned for a CubeSat form factor under GSFC internal funding; 2) the digital back end (DBE), a modification of the Cion instrument flying on CICERO that capitalizes on the extensive heritage of the Blackjack and TriG GPS receivers; and 3) an array of COTS antennas.

LNFE has a patent-pending architecture that uses an internal calibration network based upon our experience with the Aquarius and SMAP missions. It also is capable of antenna swapping to suppress the effects of antenna phase and gain imbalances. RF circuits are shielded from out of band signals and spacecraft-generated electromagnetic interference (EMI).

DBE employs a combination of off-the-shelf hardware with a custom-designed RF/CLK/Host board and will be modified to accommodate the rad-tolerant Space Micro CubeSat Space Processor (CSP) to make the instrument suitable for a future NASA Class D mission. Four P-band down-converters and a high-performance sampling clock are used to acquire data in two polarizations from the two antennas (zenith and nadir).

Success with SNoOPI will retire the critical risks associated with a P-band SoOp satellite mission, and we will exit with a TRL-7 instrument. This instrument will enable direct measurements of RZSM and SWE that are not presently possible and will also be orders of magnitude lower in size weight and power (SWaP) than comparable active radars due to the re-utilization of powerful anthropogenic signals. Coupled with the use of small, wide beam antennas, a P-band SoOp mission is an ideal candidate for a large constellation of micro-satellites or hosted payloads. This constellation could be proposed to a future Earth Venture/Continuity or Earth System Explorer program.

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Robert Wright, University of Hawaii, Honolulu
Hyperspectral Thermal Imager (HyTI)

Objectives and Benefits: Design, build, assemble, test and fly a 6U CubeSat Low Earth Orbital (LEO) demonstration of HyTI (Hyperspectral Thermal Imager) as a “pathfinder” enabling the next generation of high spatial, spectral and temporal resolution thermal infrared (TIR) imagery acquisition from LEO. Monitoring Global Hydrological Cycles and Water Resources, and developing a detailed understanding of the movement, distribution and availability of water and its variability over time and space is a critical need for NASA’s Decadal Strategy for Earth Observation from Space. An associated need is the measurement of land surface dynamics by monitoring the continuous variability of land surface temperature (LST). While LEO hyperspectral TIR observations will enable detailed measurements of both hydrological and LST variability, the focus will be on enabling agricultural remote sensing. HyTI will be designed to investigate the following global food and water security issues:
1. Mapping both irrigated and rainfed cropland areas;
2. Determining crop water use (actual evapotranspiration (ET)) of major world crops
3. Establishing crop water productivity (“crop per drop”) of major world crops.

The novel HyTI technologies to be space validated for the first time via LEO flight are:
1. Hyperspectral Imager: The HyTI Hyperspectral Imager instrument will be designed and developed by HSFL and the Hawaii Institute of Geophysics and Planetology (HIGP). Both HSFL and HIGP have a well-established track record of designing and successfully demonstrating state-of-the-art small satellites and imaging payloads ranging from the visible to the IR, including compact hyperspectral imaging for remote-sensing observations. Based on the Fabry-Perot Interferometer principle, the HyTI Hyperspectral Imager is a unique instrument (TRL 5), and will deliver spatial resolution similar to current Landsat-8 performance, but with higher spectral resolution. In a 430 km orbit, the HyTI instrument will have ground sampling resolution of 60m for up to 50 spectral samples in the 8.0-10.7 micron wavelength range, with a peak signal-to-noise ratio of ~500:1. HIGP has successfully demonstrated the proposed “no moving parts” hyperspectral imager for a wide range of Department of Defense programs, as well as for a NASA Instrument Incubator Program.

2. TIR Imager Focal Plane: The heart of the HyTI hyperspectral imager is a 2 Dimensional, BIRD FPA designed and developed at JPL. BIRD imagers have high uniformity, low cost, low noise and higher operating temperatures than previously-flown TIR FPAs. JPL will supply the 2D FPA within an Integrated Dewar Cooler Assembly to HSFL.

3. High-Performance Onboard Computing: Onboard computing (OBC) has been the “holy grail” of scientific, remote-sensing missions. The extremely high volume (estimated 3 Petabytes over a nominal 1 year mission life) of raw hyperspectral imagery justifies the implementation of OBC. SaraniaSat Inc. has developed fast, low computational “footprint” algorithms for weak-signal detection, sensor fusion and orthorectification which, when operating on the advanced Unibap e2160 heterogeneous OBC platform, promise to achieve fast turnaround (within 24 hrs of acquisition) of the processed data and information products.

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David Harber, University Of Colorado, Boulder
Compact Total Irradiance Monitor Flight Demonstration

The long-term balance between Earth’s absorption of solar radiative energy and emission of radiation to space is a fundamental climate measurement required in the NRC’s Decadal Survey report Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. Total solar irradiance (TSI) has been measured from space by a 40-year uninterrupted sequence of instruments. We propose to build and fly a next-generation TSI instrument on a 6U CubeSat, the Compact Total Irradiance Monitor (CTIM). This instrument will meet the measurement requirements of the previous generation instruments while being compact enough to fit on CubeSat platform. In order to accomplish this the CTIM will utilize new technologies, including silicon-based vertically aligned carbon nanotube (VACNT) bolometers. The goal of this program is to demonstrate and raise the TRL of next-generation technology which will permit the measurement of TSI from a CubeSat platform. This compact, lower-mass instrument has shorter fabrication times and lower costs which should provide more flight opportunities, helping reduce the risk of future TSI-measurement data gaps.

This program will run from September 17, 2018 through September 17, 2021. We will first rebuild key elements of the CTIM instrument developed during the CTIM Instrument Incubator Program (IIP) program, incorporating lesson learned from the environmental and performance testing of the CTIM. We will then procure and integrate a Blue Canyon Technologies XB1 CubeSat bus. The integrated system will undergo environmental, performance, and end-to-end testing. The target launch date of the CTIM-FD is September 2020.

The planned one-year mission will test the on-orbit performance of the CTIM-FD directly against Total and Spectral Solar Irradiance Sensor (TSIS) Total Irradiance Monitor (TIM) currently operating on the International Space Station. During this measurement we will test the initial measurement accuracy of the CTIM, and the long-term stability of the measurements over the mission life. The CTIM entry TRL is 5, based on prototype testing work performed on the Carbon Absolute Electrical Substitution Radiometers (CAESR) Advanced Component Technologies (ACT) project and the related Compact Spectral Irradiance Monitor (CSIM) IIP project. The planned exit TRL is 7-9 based on successful on-orbit operations.

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Steven Love, Los Alamos National Security, LLC
Compact high-resolution trace-gas hyperspectral imagers, with agile on-board processing

Detecting, mapping, and quantifying dilute trace gases via spectral imaging is a capability of enormous value to the earth sciences, from atmospheric science and climate change, to biosphere monitoring, to volcanology. This capability is technologically demanding, however, requiring both high spectral resolution and high sensitivity, traditionally driving investigators to large, complex instruments requiring expensive large-satellite hosts. Furthermore, high-resolution spectral imaging, i.e. hyperspectral imaging (HSI), generates huge volumes of data that must be subjected to detailed analysis to extract and interpret the gas signatures of interest, something traditionally requiring the large downlink bandwidth only available on large satellite platforms.

This proposed project seeks to enable a paradigm shift in spaceborne trace gas spectral imaging, from expensive single-platform instruments, to agile constellations of relatively inexpensive instruments on small satellites. Such constellations could be tailored to offer much more favorable combinations of spatial resolution and revisit time, important, e.g., for monitoring low-level volcanic activity or anthropogenic gas emissions, than could be achieved by any single instrument, even given the constraints and limitations of the small-sat platforms. One can even imagine one satellite in the constellation identifying targets of interest and cueing subsequent satellites to investigate in other spectral regions or at higher spatial resolution.

Key to this vision is the development of ultra-compact spectral imagers that are competitive in terms of throughput and resolution with their large-satellite-based cousins, and the development of a fast, sensitive, and computationally efficient on-board processing capability so that huge hyperspectral data sets need not be downlinked for analysis. In this project we propose to demonstrate and validate on-orbit both of these capabilities.

Under internal funding, we have designed, and are in the process of building, an ultra-compact hyperspectral imager designed to mate with LANL’s highly successful CubeSat bus. Operating in the 300-500nm spectral region, with f/2 optics, 0.6nm spectral resolution, 320 spectral channels, and 320 across-track spatial pixels, the instrument would target NO2, SO2, ozone, formaldehyde, and other gases, with sufficient spectral resolution to confidently separate the trace gas signatures from the atmosphere. Scientific missions include monitoring and characterizing anthropogenic fossil fuel burning, and monitoring low-level passive SO2 degassing at volcanoes. In terms of spectral resolution and predicted sensitivity, our miniature instrument is comparable to NASA’s Ozone Mapping Instrument (OMI) but is aimed at narrow field-of-view targeted observations (roughly 0.5 km spatial resolution from 500 km altitude) rather than OMI’s global mapping. The spectrometer package occupies a 1.5 U CubeSat module; coupled with the LANL CubeSat host and payload interposer module, the entire satellite comprises a 3U system.

In conjunction with the optical hardware, we have been developing, and testing on our CubeSat’s on-board processor, streamlined hyperspectral gas retrieval algorithms that run many times faster than traditional methods. Tests on OMI data demonstrate that these algorithms can achieve sensitivity comparable to more exhaustive standard approaches. Importantly, the LANL CubeSat system allows for on-orbit software uploads, so that on-board retrieval algorithms can be tested and modified throughout the mission.

Our project would build and launch our full CubeSat-hosted HSI system, with the aim of validating our ultra-compact optical and cutting-edge on-board retrieval strategies, and demonstrating competitive, scientifically useful trace gas sensitivities, with rapid turnaround on-board retrievals, on small-sat platforms.