2012 InVEST Projects Announced
NASA Science Mission Directorate
Research Opportunities in Space and Earth Sciences
A.48 In-Space Validation of Earth Science Technologies (InVEST)
05/03/2013 – 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.
The InVEST call 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. The ESD has selected 4 out of a total of 23 received proposals in response to this solicitation. The total first-year funding for these investigations is approximately three million dollars.
The Microwave Radiometer Technology Acceleration (MiRaTA) 3U CubeSat, will: 1) Validate new ultra-compact and low-power technology for CubeSat-sized microwave radiometers operating near 52-58, 175-191, and 206-208 GHz; 2) Validate new GPS receiver and antenna array technology necessary for CubeSat tropospheric radio occultation sounding, and 3) Test a new approach to radiometer calibration using concurrent GPS radio occultation (GPSRO) measurements. A slow pitch up/down maneuver will be executed once per orbit to permit the radiometer and GPSRO observations to sound overlapping volumes of atmosphere through the Earth’s limb, where sensitivity, calibration, and dynamic range are optimal. These observations will be compared to radiosondes, global high-resolution analysis fields, other satellite observations, and with each other using radiative transfer models. The radiometer and GPSRO technology elements, currently at TRL5 but to be advanced to TRL7 at mission conclusion, are functionally independent but highly synergistic, and are all readily accommodated in a single 3U CubeSat to be launched into an ISS orbit at 390km/52° for low-cost validation. These new capabilities would directly improve Earth Science measurements in several ways. MiRaTA will demonstrate high-fidelity, well-calibrated radiometric sensing from a nanosatellite platform, thereby enabling new architectural approaches for mission implementation at lower cost and risk with more flexible access to space. In addition, measurement quality can be substantially improved relative to present systems through the use of proximal GPSRO measurements as a calibration standard for radiometric observations, reducing and perhaps eliminating the need for costly and problematic internal calibration targets. This 90-day mission will mark the first ever implementation of co-located radiometer+GPSRO sounding and the first CubeSat implementation of both temperature+humidity radiometric sounding and GPSRO atmospheric sounding. Therefore, MiRaTA will not only validate multiple subsystem technologies, but will also demonstrate new sensing modalities that would dramatically enhance the capabilities of future weather and climate sensing architectures.
The objective of the Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) is to demonstrate a radiometer that is compact, low cost, and absolutely accurate to NIST traceable standards. RAVAN and CubeSats allow for constellations that are affordable in sufficient numbers to measure Earth’s radiative diurnal cycle and absolute energy imbalance to climate accuracies (globally at 0.3 W/m2) for the first time. The key technologies that enable a radiometer with all of these attributes are: a gallium fixed-point black body as a built-in calibration source, and a vertically aligned carbon nanotube (VACNT) absorber. VACNTs are the blackest known substance, making them ideal radiometer absorbers with order-of-magnitude improvements in spectral flatness and stability over the existing art. Neither the VACNT, nor gallium black body has ever been used in an orbiting instrument, and successful demonstration will raise these technologies and RAVAN from TRL from 5 to 7, paving the way for a constellation Earth radiation budget mission that can provide the measurement that is needed to enable vastly superior predictions of future climate change, serving the goals outlined in NASA’s “Climate-Centric Architecture.”
The heritage APL 3U Multi-Mission Nanosat will host RAVAN, providing the reliability, agility, and resources needed with ample mass, power, volume, and data handling margins. The RAVAN period of performance is from May 2013 through April 2016. The first project year focuses on radiometer development. The second year includes spacecraft development, instrument integration, and spacecraft level testing ending in encapsulation. The third year features launch, flight and instrument operations, and data validation. Spaceflight Inc. will provide launch near July 2016. APL, L-1 Standards and Technologies, Inc., and GSFC have been working for more than two years to establish the basis for this exciting technology and are eager to pursue this opportunity to bring forth the successful flight of RAVAN.
The objective of this proposal is to demonstrate in space, a new detector with high quantum efficiency and single photon level response at several important remote sensing wavelength detection bands from 0.9 to 4.0 microns. A key element of this demonstration will include the characterization of the detector’s response and dark current levels for specific detection periods as a function of exposure time and thus integrated space based radiation dosage.
The detector being demonstrated will be a 2 by 8 HgCdTe Avalanche Photo Diode (APD) array developed by DRS -RSTA in Richardson, Texas. The detector will be housed in a small 80K tactical cooler. Currently, there is no space-qualified photon level counting detector at >1-micron which is compatible with long-term space operation. Because a qualified single photon multi-pixel detector was not available at 1 micron, the ICESat-2 mission had to convert its 1-micron laser into the green, which significantly increased the instrument’s power and complexity. There are significant NASA needs for photon sensitive IR detector arrays for the ASCENDS, LIST and other planned missions.
For this experiment, we will integrate the detector assembly into a 3U cubesat built by the Aerospace Corporation. This will accommodate the DRS device, and will have attitude knowledge and control and ground connectivity similar to the Aerospace cubesats currently operating in space. The experiment only requires the cubesat to point to the ground station and support the detector and cooler operation over short time periods (5 minutes) for multiple missions per week. This mission design significantly simplifies the cubesat hardware design, but provides a long term monitoring of the detector characteristics in a low earth orbit environment.
The baseline on-orbit test will use an on-board broad-band optical source integrated with a selectable cubesat flight proven filter mechanism which optically illuminates the detector. We will also endeavor to use the sunlit Earth as another test source and compare the results with multispectral images taken by other Earth observing satellites. A more challenging goal, will involve orienting the cubesat so that it acquires and records laser emissions from our ground station as a one-way lidar to aid in establishing more dynamic operating envelopes for the device compatible with several earth science missions, including LIST, ASCENDS, follow-on ICESat missions, photon-counting laser communications and passive spectrometers in the shortwave to midwave infrared band. To understand radiation exposure details, we will integrate for the first time in a cubesat, the Aerospace dosimeter which was licensed to Teledyne and flew on NASA/LRO, and NASA RBSP-ECT/RPS.
The HyperAngular Rainbow Polarimeter (HARP) Cubesat mission objectives:
- Space validation of new technology required by the Tier 2 Decadal Survey Aerosol-Cloud-Ecosystem (ACE) mission science definition team.
- Prove the on-flight capabilities of a highly accurate wide FOV hyperangle imaging polarimeter for characterizing aerosol and cloud properties.
The HARP payload is a wide field of view (FOV) imager that uses modified Philips prisms to split 3 identical images into 3 independent imaging detector arrays. This technique achieves simultaneous imagery of the 3 polarization states and is the key innovation to achieve high polarimetric accuracy with no moving parts. The spacecraft consists of a 3U Cubesat with 3-axis stabilization designed to keep the polarimeter pointing nadir. An airborne version of HARP was flown on the NASA DC-8 during the DC3 field experiment during the summer of 2012. The performance of the airborne version was excellent with accuracy of linear degree of polarization to within 0.3%.
The proposed spacecraft has already participated in a space mission and is at TRL = 8. The sensor is at TRL = 6. At exit, TRL for wide FOV hyperangle imaging polarimetry will be 8. The proposed time line for HARP Cubesat is two years to reach launch, 3 months on-orbit for technology validation and an optional continuation of 9 months of data collection for separate science objectives funded by NOAA. The integrated spacecraft can be ready for launch by December 2014.
The HARP Cubesat mission will be a joint effort between UMBC who will provide the sensor hardware and characterization, and scientific analysis; SDL who will provide the 3U Cubesat spacecraft and mission operations; and STC who will lead the science algorithm development and science application funded by NOAA. NASA Wallops will support instrument environmental testing, mission operations, and communications.