Debi Rose

CYGNSS: Enabling the Future of Hurricane Prediction [Remote Sensing Satellites]

The CYGNSS mission introduces a new paradigm in low-cost Earth science missions that employs a constellation of science-based microsats to fill a gap in capabilities of existing large systems at a fraction of the cost. The CYGNSS observatories will make frequent wind observations, and wind observations in precipitating conditions, using GPS reflectometry to observe the TC inner core ocean surface. These efforts will result in unprecedented coverage of windswithin a TC throughout its life cycle and thus provide critical data necessary for advancing the forecast of TC intensification.

The CYGNSS ground segment; innovative mission operations concepts to support a micro-satellite constellation

Hurricane track forecasts have improved in accuracy by ~50% since 1990, while in that same period there has been essentially no improvement in the accuracy of intensity prediction. One of the main problems in addressing intensity occurs because the rapidly evolving stages of the tropical cyclone (TC) life cycle are poorly sampled in time by conventional polar-orbiting, wide-swath surface wind imagers. NASAs most recently awarded Earth science mission, the NASA EV-2 Cyclone Global Navigation Satellite System (CYGNSS) has been designed to address this deficiency by using a constellation of micro-satellite-class Observatories designed to provide improved sampling of the TC during its life cycle. Managing a constellation of Observatories has classically resulted in an increased load on the ground operations team as they work to create and maintain schedules and command loads for multiple Observatories. Using modern tools and technologies at the Mission Operations Center (MOC) in conjunction with key components implemented in the flight system and an innovative strategy for pass execution coordinated with the ground network operator, the CYGNSS mission reduces the burden of constellation operations to a level commensurate with the low-cost mission concept. This paper focuses on the concept of operations for the CYGNSS constellation as planned for implementation at the CYGNSS MOC in conjunction with the selected ground network operator.

Juggling Spacecraft: Similarities and differences of eight microsatellites for the CYGNSS mission

The goal of any system in which there is a large set of components that are mostly similar, but have a non-negligible set of differences, is to find the balance between a “one-size-fits-all” approach, and a “unique-per-system-and-customizable” approach. This paper discusses how the balance between these two extremes is achieved as part of the ground segment and flight segment that will support the eight microsatellites of the National Aeronautics and Space Administration (NASA) Cyclone Global Navigation Satellite System (CYGNSS) mission. The NASA CYGNSS mission aims to understand the coupling between ocean surface properties, moist atmospheric thermodynamics, radiation, and convective dynamics in the inner core of Tropical Cyclones (TCs). The mission is comprised of eight microsatellites in Low-Earth Orbit (LEO) at an inclination of 35 degrees. As discussed in “The CYGNSS Ground Segment: Innovative Missions Operations Concepts to Support a Micro-Satellite Constellation” [1], previously presented at IEEE Aerospace 2013, the ground segment system must take into account the unique aspects of each microsatellite, including unique Spacecraft Identification (SCID) schemes, setup of multiple ground system consoles, definition of telemetry limits unique to a microsatellite, and any unique table or command loads. This paper expands upon the previously presented paper on the ground segment, and discusses how each of these details has been addressed in the implementation of the CYGNSS mission. This includes discussion of how Spacecraft I/Ds are defined onboard via the avionics, how the FSW table configurations vary between microsatellites, and whether or not a “one-size-fits-all” approach of FSW images is necessary for each microsatellite. The CYGNSS mission completed Preliminary Design Review (PDR) in 2014, Critical Design Review (CDR) in 2015, and is expected to launch in late 2016.

CYGNSS MOC; Meeting the challenge of constellation operations in a cost-constrained world

The Cyclone Global Navigation Satellite System (CYGNSS), selected as part of NASAs Earth Venture program and launching in 2016, will use an 8 observatory micro-satellite constellation to enhance the understanding of tropical cyclone intensity development. Operating the CYGNSS constellation in a cost effective manner is a fundamental cornerstone of achieving significant science return in a cost-constrained environment. The Southwest Research Institute (SwRI) has developed an innovative Mission Operations Center (MOC) designed to accommodate the constellations significant planning and data downlink requirements [2]. The large number of data downlink opportunities necessitates a MOC that can easily identify and schedule ground contacts, and autonomously run the ground contact events from initiation of acquisition to delivery of the L0 science data. This paper will discuss the commercial off-the-shelf (COTS) and Government off-the-shelf (GOTS) tools leveraged, as well as in-house developed software that allow the CYGNSS MOC to meet the constellation operational challenge in a cost effective manner.

Accommodating Navigation Uncertainties in the Pluto Encounter Sequence Design

The New Horizons encounter with the Pluto system was a historic achievement in planetary exploration. Launched on January 19, 2006, the spacecraft executed its close encounter with Pluto on July 14, 2015, acquiring the first-ever close up data of Pluto, its five known satellites, and the surrounding plasma and particle environment. During its 9½ year cruise, the spacecraft also conducted a flyby of an asteroid in 2006 and a Jupiter gravity assist in 2007 during which over 700 observations of Jupiter, the Galilean satellites, and the plasma and particle environment near Jupiter were acquired. Led by Principal Investigator Alan Stern, New Horizons was the first launch of NASA’s New Frontiers Program and the first mission to Pluto and the Kuiper Belt.

The MMS Burst System; Co-operative concept of flight-ground operations to maximize burst system science data return

The Magnetospheric MultiScale (MMS) mission is a 2 year mission that will study reconnection in the Earths magnetosphere. The four MMS observatories will be required to fly in a tetrahedral formation in order to unambiguously determine the orientation of the magnetic reconnection layer. At highest resolution, the Instrument Suite (IS) on each MMS spacecraft will produce scientific measurements many times faster than the orbit-averaged telemetry rate. Although high-resolution measurements are essential to understanding magnetic reconnection, these measurements are needed on the ground for only a fraction of the orbit. Within the MMS system, the flight Burst System is designed to store the high- resolution data for the full time during the period of the orbit, called the Region of Interest (ROI), that is the most likely to contain the magnetic reconnection events. Then, the ground portion of the Burst System is designed to select snippets (typically one to five minutes in duration) of the high resolution data that are most likely to contain a reconnection event. On the MMS mission, to determine when a reconnection event may have occurred, it is necessary to correlate data from all four MMS observatories. Avoiding the complexity of having four observatories communicating every 10 seconds within a 12 or 36 hour ROI was a primary driver to the creation of a shared flight-ground responsibility for the Burst Data selection activity. This paper outlines the key flight and ground segment elements that are being implemented to support this co-operative flight-ground operations approach to the Burst Data selection process, as well as outlining some of the primary challenges associated with this flight-ground split of responsibilities.

Software engineering processes for Class D missions

Software engineering processes are often seen as anathemas; thoughts of CMMI key process areas and NPR 7150.2A compliance matrices can motivate a software developer to consider other career fields. However, with adequate definition, common-sense application, and an appropriate level of built-in flexibility, software engineering processes provide a critical framework in which to conduct a successful software development project. One problem is that current models seem to be built around an underlying assumption of “bigness,” and assume that all elements of the process are applicable to all software projects regardless of size and tolerance for risk. This is best illustrated in NASA’s NPR 7150.2A in which, aside from some special provisions for manned missions, the software processes are to be applied based solely on the criticality of the software to the mission, completely agnostic of the mission class itself. That is, the processes applicable to a Class A mission (high priority, very low risk tolerance, very high national significance) are precisely the same as those applicable to a Class D mission (low priority, high risk tolerance, low national significance). This paper will propose changes to NPR 7150.2A, taking mission class into consideration, and discuss how some of these changes are being piloted for a current Class D mission—the Cyclone Global Navigation Satellite System (CYGNSS).