The University of California, Berkeley conducts mission operations for eight spacecraft at present. Communications with the orbiting spacecraft are established via a multitude of network resources, including all NASA networks, plus assets provided by foreign space agencies and commercial companies. Mission planning is based on the science requirements as well as accessibility to communications network resources. The integrated scheduling process is complex and is supported by partly automated software tools. Challenges encountered and lessons learned are described.
The University of California, Berkeley has conducted flight operations for eight NASAfunded satellites from its highly automated Multi-mission Operations Center, located at Space Sciences Laboratory. To implement operations for a new mission, namely the Nuclear Spectroscopic Telescope Array, the Berkeley operations team took a different, proactive approach towards supporting all phases of spacecraft bus and instrument development. Transportable clones of the already operational, integrated ground systems, including spacecraft command and control systems, telemetry data processing and trending analysis systems, and other software tools are pre-configured at Berkeley and deployed at various integration and test facilities. Members of the operations team work directly with the spacecraft contractor and the instrument developers to create telemetry and command dictionaries, telemetry display pages and scripts, and participate in all test activities as console operators. During subsystems and systems testing, telemetry data are streamed from remote locations into a central database at Berkeley to allow for real-time and post-test trending analysis. Tying the operations center into all spacecraft development and test phases reverses the conventional flow of activities and ensures a smooth transition to launch and on-orbit operations. This approach also provides excellent training opportunities for the entire flight operations team, beginning more than two years prior to launch. We describe details of the operations implementation, as well as lessons learned.
The SAtellite VAlidation Navy Tool (SAVANT) was developed by the Navy to help facilitate the assessment of the stability and accuracy of ocean color satellites using ground truth (insitu) platform and buoy stations positioned around the globe and support methods for match-up protocols. This automated, continuous monitoring system for satellite ocean color sensors employs a website interface to extract and graph coincident satellite and insitu data in near-real-time. Available satellite sensors include MODerate resolution Imaging Spectrometer (MODIS) onboard the Aqua satellite, Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar-orbitting Partnership (SNPP) & Joint Polar Satellite Sensor (JPSS), Ocean and Land Colour Instrument (OLCI) onboard the Sentinel 3A and Geostationary Ocean Color Imager (GOCI) onboard the Communication, Ocean and Meteorological Satellite (COMS). SAVANT houses an extensive match-up data set covering nineteen plus years (2000- 2019) of coincident global satellite and ground truth spectral Normalized Water Leaving Radiance (nLw) data allowing users to evaluate the accuracy of ocean color sensors spectral water leaving radiance at specific ground truth sites that provide continuous data. The tool permits changing different match-up constraints and evaluating the effects on the match-up uncertainty. Results include: a) the effects of spatial selection (using single satellite pixel versus 3x3 and 5x5 boxes, all centered around the insitu location), b) time difference between satellite overpass and ground truth observations, c) and satellite and solar zenith angles. Match-up uncertainty analyses was performed on VIIRS SNPP at the AErosol RObotic NETwork Ocean Color (AeroNET-OC) Wave Current surge Information System (WavCIS) site, maintained by NRL and the Louisiana State University (LSU) in the North Central Gulf of Mexico onboard the Chevron platform CSI-06. The VIIRS SNPP and AeroNET-OC assessment determined optimal satellite ocean color cal/val match-up protocols that reduced uncertainty in the derived satellite products.
The Naval Research Laboratory (NRL) has established a Regional Coastal Oceanography with Nanosatellites (ReCON) project which will explore the ability of high-resolution nanosatellites to monitor coastal, estuarine, riverine, and other maritime environments in support of U.S. Navy operations. The project will initially focus on using data from the almost 150+ Planet "Dove" nanosatellites which fly in "flocks" acquiring remotely sensed data from sunlight reflecting off the earth surface. The usefulness of remotely sensed data within our research and operations is determined by the ability to accurately perform atmospheric correction and compute water leaving radiances (Lw), which are then normalized (nLw) and form the basis for the generation of remote sensing reflectance and other inherent and apparent optical property products. These nanosatellites have a single infrared band, although two such bands are typically required to automatically select an appropriate aerosol model during atmospheric correction, prior to estimating nLw. While early in the project, this initial study will assess nanosatellite capabilities to accurately retrieve nLw measurements by specifying the aerosol model selection during the atmospheric correction process. Here we present nLw retrievals for a variety of Planet nanosatellite imagery covering an entire year over a northern island of Venezuela, which covers coastal and open ocean type waters. The nLw retrievals from the nanosatellites using forced aerosol models are compared to coincident nLw retrievals from the Suomi-National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) to gauge the potential reliability and accuracy of using nanosatellite imagery as a competent data source for ocean color optics.
UC Berkeley's Space Sciences Laboratory (SSL) currently operates a fleet of seven NASA satellites, which conduct research in the fields of space physics and astronomy. The newest addition to this fleet is a high-energy X-ray telescope called the Nuclear Spectroscopic Telescope Array (NuSTAR). Since 2012, SSL has conducted on-orbit operations for NuSTAR on behalf of the lead institution, principle investigator, and Science Operations Center at the California Institute of Technology. NuSTAR operations benefit from a truly multi-mission ground system architecture design focused on automation and autonomy that has been honed by over a decade of continual improvement and ground network expansion. This architecture has made flight operations possible with nominal 40 hours per week staffing, while not compromising mission safety. The remote NuSTAR Science Operation Center (SOC) and Mission Operations Center (MOC) are joined by a two-way electronic interface that allows the SOC to submit automatically validated telescope pointing requests, and also to receive raw data products that are automatically produced after downlink. Command loads are built and uploaded weekly, and a web-based timeline allows both the SOC and MOC to monitor the state of currently scheduled spacecraft activities. Network routing and the command and control system are fully automated by MOC's central scheduling system. A closed-loop data accounting system automatically detects and retransmits data gaps. All passes are monitored by two independent paging systems, which alert staff of pass support problems or anomalous telemetry. NuSTAR mission operations now require less than one attended pass support per workday.
THEMIS is a five-spacecraft constellation launched in 2007 to study magnetospheric phenomena leading to the aurora borealis. During the primary mission phase, completed in the fall of 2009, all five spacecraft collected science data in synchronized, highly elliptical Earth orbits. For an ambitious mission extension, the Project proposed to split the constellation into two parts - THEMIS-Low and ARTEMIS. THEMIS-Low includes the three spacecraft on the inner orbits with approximately one-day periods, continuing their study of the magnetosphere in a tighter formation. ARTEMIS involves transferring the outer two spacecraft from their Earth orbits with two and four-day periods into lunar orbits to conduct measurements of the interaction of the Moon with the solar wind and of crustal magnetic fields. This transfer was initiated on July 21, 2009 and follows low-energy trajectories with Earth and lunar gravity assists. The THEMIS mission is controlled from the highly automated multi-mission operations center at the University of California, Berkeley and was originally designed to be supported by 11-m class ground stations and NASA's Space Network. To increase the telemetry bandwidth for science data return at lunar distances, the mission network was expanded to also include the 34-m subnet of NASA's Deep Space Network (DSN). This paper discusses all aspects of the process to seamlessly integrate the new DSN interfaces into the THEMIS/ARTEMIS mission control network, and describes challenges and lessons learned with the implementation of real-time telemetry and command data transfer using the CCSDS Space Link Extension protocol. It also includes on-orbit characterization of the transponder ranging channels, orbit determination results using two-way Doppler and range data from a combination of conventional ground stations and DSN stations, as well as pass scheduling via the DSN Resource Allocation Planning Service and via automated, electronic data exchanges. All of these tasks were accomplished within a compressed schedule of one year, with very limited staffing resources, and on a tight budget.
THEMIS-a five-spacecraft constellation - is a NASA Medium Explorer mission that was launched in 2007 and maneuvered into synchronized, highly elliptical Earth orbits to study magnetospheric physics leading to the appearance of the aurora borealis. THEMIS operations are conducted from the multi-mission control center at the University of California, Berkeley. After a successful completion of the prime mission phase in fall of 2009, all five spacecraft and the ground systems are still performing very well. The excellent flight and ground systems performance can in part be traced back to a carefully designed and meticulously executed mission readiness test program, as well as operations planning and extensive operator training. This paper describes the methodology of the mission readiness test program, its organization from box level to full systems level end-to-end testing, and includes lessons learned that may be directly applicable towards future missions.
