TEMPEST-D (Temporal Experiment for Storms and Tropical Systems Technology - Demonstration)
TEMPEST-D is a CubeSat student project of CSU (Colorado State University) Fort Collins, CO, with the objective to demonstrate the ability to monitor the atmosphere with small satellites. The team will demonstrate a radiometer aboard a 6U CubeSat (30 cm x 20 cm x 10 cm) and subsequently plan to deploy a constellation of satellites to study cloud processes. The student team, led by Steven Reising, professor of electrical and computer engineering, is developing instrumentation for CubeSats that can observe, in real time, a storm as it grows and progresses. 1)
TEMPEST-D will reduce the risk, cost and development time of a future constellation of 6U-Class nanosatellites to directly observe the time evolution of clouds and study the conditions that control the transition from non-precipitating to precipitating clouds using high-temporal resolution observations. TEMPEST-D provides passive millimeter-wave observations using a compact radiometer (90-183 GHz) that fits well within the size, weight and power (SWaP) requirements of the 6U-Class satellite architecture. TEMPEST-D is suitable for launch through NASA's CSLI (CubeSat Launch Initiative), for which it was selected in February 2015. 2) 3)
By measuring the temporal evolution of clouds from the moment of the onset of precipitation, a TEMPEST constellation mission would improve our understanding of cloud processes and help to constrain one of the largest sources of uncertainty in climate models. Knowledge of clouds, cloud processes and precipitation is essential to our understanding of climate change. Uncertainties in the representation of key processes that govern the formation and dissipation of clouds and, in turn, control the global water and energy budgets lead to substantially different predictions of future climate in current models.
The goal of the TEMPEST-D is a mission to validate the performance of a CubeSat microwave radiometer designed to study precipitation events on a global scale. The TEMPEST constellation of 6U CubeSats is designed to sample convective precipitation events, from cloud formation, through ice formation and precipitation to cloud dissipation. 4)
The TEMPEST-D project is to increase the TRL (Technology Readiness Level) of the millimeterwave radiometer instrument from 6 to 9. 5)
The TEMPEST-D mission success criteria for a 90-day mission after on-orbit commissioning are as follows:
1) To demonstrate feasibility of differential drag measurements required to achieve the desired time separation of 6U-Class satellites deployed together in the same orbital plane.
2) To demonstrate cross-calibration with 2 K precision and 4 K accuracy between TEMPEST-D millimeter-wave radiometers and the NASA/JAXA GPM/GMI or the Microwave Humidity Sounder currently in orbit on two NOAA satellites and two ESA/EUMETSAT satellites.
TEMPEST-D is a partnership among CSU, JPL and spacecraft provider BCT (Blue Canyon Technologies Inc.) of Boulder, CO. BCT has recently been awarded a contract to build, test, and operate a new 6U-class satellite. BCT will deliver the 6U spacecraft, ready for instrumentation, for the TEMPEST-D project, led by CSU (Colorado State University), Fort Collins, CO. TEMPEST-D is supported by NASA's Science Mission Directorate, Earth Science Division and is managed by NASA's ESTO (Earth Science Technology Office). NASA/JPL(Jet Propulsion Laboratory) will provide the five-channel millimeter-wave radiometer instrument. 6)
BCT will integrate the TEMPEST-D payload with the 6U spacecraft bus and perform environmental testing of the complete spacecraft. The spacecraft will be operated from BCT's Mission Operations Center in Boulder, Colorado. BCT's 6U spacecraft is a high-performance CubeSat that includes an ultra-precise attitude control system that allows for accurate knowledge and fine-pointing of the satellite payload.
Figure 1: Artist's rendition of the deployed TEMPEST-D nanosatellite (image credit: BCT, CSU)
ADCS (Attitude Determination and Control Subsystem): BCT uses the XACT-50 (fleXible ADCS Cubesat Technology-50) for 6U CubeSats. The XACT-50 improves the capability of XACT by incorporating larger reaction wheels and torque rods.
Table 1: Parameters of XACT-50
Figure 2: Illustration of the XACT-50 device (image credit: BCT)
The complete TEMPEST-D flight system will be delivered to NanoRacks for launch integration in the autumn of 2017, spacecraft mass: 6 kg).
Launch: TEMPEST-D is scheduled for launch to the ISS in Q2 of 2018. The launch vehicle is Cygnus CRS OA-9E, also known as Orbital Sciences CRS Flight 9E, the tenth planned flight of the Orbital ATK unmanned resupply spacecraft Cygnus. The launch site is MARS (Mid-Atlantic Regional Spaceport), VA, USA.
Orbit: Near circular orbit, altitude of ~400 km, inclination = 51.6º.
Sensor complement: (MM Radiometer)
MM Radiometer (Millimeter-wave Radiometer)
The MM radiometer is being built by NASA/JPL and performs continuous measurements at five frequencies, 89, 165, 176, 180 and 182 GHz. The five-frequency radiometer is based on the direct-detection architecture, in which the RF input to the feed horn is amplified, bandlimited, and detected using Schottky diode detectors. 7) The use of direct-detection receivers based on InP HEMT MMIC LNA front ends substantially reduces the mass, volume and power requirements of these radiometers. 8) Input signals are bandlimited using waveguide-based bandpass filters to meet the radiometer bandwidth requirements of 4±1 GHz at center frequencies of 89 and 165 GHz, as well as 2±0.5 GHz at 176, 180 and 182 GHz center frequencies (Ref. 5).
The TEMPEST-D instrument design is based on a 165 GHz to 182 GHz radiometer design inherited from RACE and an 89 GHz receiver developed under the ESTO ACT-08 and IIP-10 programs at CSU (Colorado State University) and JPL. All receivers were jointly developed by JPL and the Northrop Grumman Corporation. The TEMPEST reflector scanning and calibration methodology has been adapted from the ATMS (Advanced Technology Microwave Sounder). This methodology has been validated on the Global Hawk unmanned aerial vehicle (UAV) using the HAMSR (High Altitude MMIC Sounding Radiometer) instrument. 9)
The TEMPEST-D instrument occupies a volume of 3U (normally defined as 34 cm x 10 cm x 10 cm) and is designed for deployment in a 6U CubeSat. The instrument is mounted on a temperature controlled bench that interfaces with the spacecraft structure using thermally isolating spacers. Figure 4 shows the mechanical layout of the instrument components on the instrument bench.
Figure 3: Instrument block diagram and photos of components (image credit: TEMPEST-D collaboration)
Figure 4: Instrument mechanical layout (image credit: TEMPEST-D collaboration)
The TEMPEST-D radiometer performs cross-track scanning, measuring the Earth scene between ±45° nadir angles, providing an 825 km wide swath from a 400 km nominal orbit altitude. Each radiometer pixel is sampled for 5 ms. The radiometer performs end-to-end calibration during each rotation of the scanning reflector. The radiometer observes both cosmic background radiation at 2.7 K and an ambient blackbody calibration target (at approximately 300 K) every 2 seconds, for a scan rate of 30 RPM. A schematic representation of the TEMPEST-D observing profile over a 360° reflector scan and the resulting output data time series are shown in Figure 5.
Figure 5: Schematic representation of TEMPEST-D observing profile (left) and output data time series (right) for each reflector scan (image credit: TEMPEST-D collaboration)
The TEMPEST-D flight model radiometer instruments (two copies, FM1 and FM2) have been designed, fabricated and integrated at JPL. Figure 6 shows the TEMPEST-D instrument, including scanning reflector (top left), dual-frequency feed horn, originally developed under a NASA ESTO Advanced Component Technology (ACT-08) program (center left), and the four radiometer channels from 165 to 182 GHz, including front-ends, power divider, bandpass filter bank and detectors. Measurements of the receiver bandpass and linearity of each of the five frequency channels have been performed at JPL.
Figure 6: TEMPEST-D flight model radiometer instrument ready for delivery at JPL (image credit: NASA/JPL)
Both TEMPEST-D flight model instruments have been integrated with the XB1 6U spacecraft avionics and bus at BCT, as shown in Figure 7. The TEMPEST-D flight model radiometer and spacecraft bus have passed electromagnetic self-compatibility tests in an anechoic chamber designed for EMI (Electromagnetic Interference)testing.
Figure 7: TEMPEST-D flight model radiometer instrument and XB1 spacecraft bus for selfcompatibility testing at BCT (image credit: TEMPEST-D collaboration)
The TEMPEST-D flight model radiometer instrument has passed vibration testing to GEVS (General Environmental Verification Standard ) levels at JPL. Figure 8 shows the TEMPEST-D flight model instrument in the configuration for vibration testing. The receiver characteristics have been measured and compared for both pre- and post-vibration testing. The next steps for the flight model radiometer instrument are TVAC (Thermal Vacuum) testing and antenna radiation pattern testing at JPL.
Figure 8: TEMPEST-D flight model radiometer instrument in vibration testing configuration at JPL (image credit: NASA/JPL)
1) Anne Ju Manning, "Small satellites to pave way for future space-borne weather observations," CSU, Dec. 2015, URL: http://source.colostate.edu/small-satellites-to-pave-the-way-for-future-space-borne-weather-observations/
2) Steven C. Reising, Todd C. Gaier, Christian D. Kummerow, Sharmila Padmanabhan, Boon H. Lim, Shannon T. Brown, Cate Heneghan, Chandrasekar V. Chandra, Jon Olson, Wesley Berg, "Temporal Experiment for Storms and Tropical Systems Technology Demonstration (TEMPEST-D): Risk Reduction for 6U-Class Nanosatellite Constellations," EGU ( European Geosciences Union) General Assembly 2016, Vienna, Austria, April 17-22, 2016, Vol. 18, paper: EGU2016-11622, URL of abstract: http://meetingorganizer.copernicus.org/EGU2016/EGU2016-11622.pdf
3) Steven C. Reising, Todd C. Gaier, Christian D. Kummerow, V. Chandrasekar, Shannon T. Brown, Sharmila Padmanabhan, Boon H. Lim, Susan C. van den Heever, Tristan S. L'Ecuyer, Christopher S. Ruf, Ziad S. Haddad, Z. Johnny Luo, S. Joseph Munchak, Timothy C. Koch, Sid A. Boukabara, "Temporal Experiment for Storms and Tropical Systems Technology Demonstration (TEMPEST-D)," NASA Earth Science Technology Forum (ESTF 2015), June 23-25, 2015 Pasadena, CA, USA, URL: https://esto.nasa.gov/forum/estf2015/presentations/Reising_S7P8_ESTF2015.pdf
4) Jason J. Hyon, Todd Gaier, Pantazis Mouroulis, Sharmila Padmanabhan, Thomas Pagano, Eva Peral, "A Status of U-class Earth Science Instruments at JPL," Proceedings of the 11th IAA Symposium on Small Satellites for Earth Observation, Berlin, Germany, April 24-28, 2017, paper: IAA-B11-0104
5) Steven C. Reising, Christian D. Kummerow, V. Chandrasekar, Wesley Berg, Jonathan P. Olson, Todd C. Gaier, Sharmila Padmanabhan, Boon H. Lim, Cate Heneghan, Shannon T. Brown, John Carvo, Matthew Pallas, "Temporal Experiment for Storms and Tropical Systems Technology Demonstration (TEMPEST-D) Mission: Enabling Time-Resolved Cloud and Precipitation Observations from 6U-Class Satellite Constellations," Proceedings of the 31st Annual AIAA/USU Conference on Small Satellites, Logan UT, USA, Aug. 5-10, 2017, paper: SSC17-III-01, URL: http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=3609&context=smallsat
6) "Blue Canyon Technologies Selected by Colorado State University and Jet Propulsion Laboratory to Provide Spacecraft for TEMPEST-D Mission," BCT, April 12, 2016, URL: http://bluecanyontech.com/blue-canyon-technologies-selected-by-colorado-state-university-and-jet-propulsion-laboratory-to-provide-spacecraft-for-tempest-d-mission/
7) D. E. Dawson, A. L. Lee, D. P. Albers, O. Montes, T. C. Gaier, D. J. Hoppe, B. Khayatian, "InP HEMT low-noise amplifier-based millimeter-wave radiometers from 90 to 180 GHz with internal calibration for remote sensing of atmospheric wet-path delay," IEEE MTT-S International Microwave Symposium Digest, Montreal, Quebec, Canada, 17-22 June 2012,
8) P. Kangaslahti, E. Schlecht, J. Jiang, W. R. Deal, A. Zamora, K. Leong, S. C. Reising, X. Bosch, M. Ogut, "CubeSat Scale Receivers for Measurement of Ice in Clouds," Proceedings of the 14th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment (MicroRad 2016), Espoo, Finland, 11-14 April 2016, pp. 42-47, DOI: 10.1109/MICRORAD.2016.7530501
9) Sharmila Padmanabhan, Todd C. Gaier, Steven C. Reising, Boon H. Lim, Robert Stachnik, Robert Jarnot, Wesley Berg, Christian D. Kummerow, V. Chandrasekar, "Radiometer payload for the temporal experiment for storms and tropical systems technology demonstration mission," Proceedings of IGARSS 2017 (IEEE International Geoscience and Remote Sensing Symposium), Fort Worth, Texas, USA, July 23–28, 2017