S. Persyn

Performance results from in-flight commissioning of the Juno Ultraviolet Spectrograph (Juno-UVS)

We present a description of the Juno ultraviolet spectrograph (Juno-UVS) and results from its in-flight commissioning performed between December 5th and 13th 2011 and its first periodic maintenance between October 10th and 12th 2012. Juno-UVS is a modest power (9.0 W) ultraviolet spectrograph based on the Alice instruments now in flight aboard the European Space Agency’s Rosetta spacecraft, NASA’s New Horizons spacecraft, and the LAMP instrument aboard NASA’s Lunar Reconnaissance Orbiter. However, unlike the other Alice spectrographs, Juno-UVS sits aboard a spin stabilized spacecraft. The Juno-UVS scan mirror allows for pointing of the slit approximately ±30° from the spacecraft spin plane. This ability gives Juno-UVS access to half the sky at any given spacecraft orientation. The planned 2 rpm spin rate for the primary mission results in integration times per 0.2° spatial resolution element per spin of only ~17 ms. Thus, for calibration purposes, data were retrieved from many spins and then remapped and co-added to build up exposure times on bright stars to measure the effective area, spatial resolution, scan mirror pointing positions, etc. The primary job of Juno-UVS will be to characterize Jupiter’s UV auroral emissions and relate them to in-situ particle measurements. The ability to point the slit will make operations more flexible, allowing Juno-UVS to observe the atmospheric footprints of magnetic field lines through which Juno flies, giving a direct connection between energetic particle measurements on the spacecraft and the far-ultraviolet emissions produced by Jupiter’s atmosphere in response to those particles.

Radiometric performance results of the Juno ultraviolet spectrograph (Juno-UVS)

We describe the radiometric performance and ground calibration results of the Juno missions Ultraviolet Spectrograph (Juno-UVS) flight model. Juno-UVS is a modest power (9.0 W) ultraviolet spectrograph based on the Alice instruments now in flight aboard the European Space Agencys Rosetta spacecraft, NASAs New Horizons spacecraft, and the LAMP instrument aboard NASAs Lunar Reconnaissance Orbiter. Its primary job will be to characterize Jupiters UV auroral emissions and relate them to in situ particle measurements.

XCAT: the JANUS x-ray coded aperture telescope

The JANUS mission concept is designed to study the high redshift universe using a small, agile Explorer class observatory. The primary science goals of JANUS are to use high redshift (6<z<12) gamma ray bursts and quasars to explore the formation history of the first stars in the early universe and to study contributions to reionization. The X-Ray Coded Aperture Telescope (XCAT) and the Near-IR Telescope (NIRT) are the two primary instruments on JANUS. XCAT has been designed to detect bright X-ray flashes (XRFs) and gamma ray bursts (GRBs) in the 1-20 keV energy band over a wide field of view (4 steradians), thus facilitating the detection of z>6 XRFs/GRBs, which can be further studied by other instruments. XCAT would use a coded mask aperture design with hybrid CMOS Si detectors. It would be sensitive to XRFs and GRBs with flux in excess of approximately 240 mCrab. In order to obtain redshift measurements and accurate positions from the NIRT, the spacecraft is designed to rapidly slew to source positions following a GRB trigger from XCAT. XCAT instrument design parameters and science goals are presented in this paper.

A hybrid PCI/VME architecture for space

Southwest Research Institute has developed a hybrid space system architecture incorporating both the VME and PCI buses. The combined architecture allows the incorporation of heritage space qualified VME modules with new high performance PCI modules, reducing development cost and providing risk mitigation at the system level. The core of the hybrid architecture is the SwRI PCI to VME Bridge (PVB), a high performance interface between the two buses. The PVB was initially prototyped using standard commercial FPGA technology, then subsequently migrated to radiation tolerant implementation, with the ultimate goal of a radiation hardened ASIC in Q4-2001.

The JANUS X-Ray Flash Monitor

JANUS is a NASA small explorer class mission which just completed phase A and was intended for a 2013 launch date. The primary science goals of JANUS are to use high redshift (6<z<12) gamma ray bursts and quasars to explore the formation history of the first stars in the early universe and to study contributions to reionization. The X-Ray Flash Monitor (XRFM) and the Near-IR Telescope (NIRT) are the two primary instruments on JANUS. XRFM has been designed to detect bright X-ray flashes (XRFs) and gamma ray bursts (GRBs) in the 1-20 keV energy band over a wide field of view (4 steradians), thus facilitating the detection of z>6 XRFs/GRBs, which can be further studied by other instruments. XRFM would use a coded mask aperture design with hybrid CMOS Si detectors. It would be sensitive to XRFs/GRBs with flux in excess of approximately 240 mCrab. The spacecraft is designed to rapidly slew to source positions following a GRB trigger from XRFM. XRFM instrument design parameters and science goals are presented in this paper.

Evolution of digital signal processing based spacecraft computing solutions

The ever-increasing information processing needs and data complexity of space exploration has motivated the constant development of higher speed DSP processor modules. These changes and the need to maximize the science data gathered and returned from satellite instruments has led to the development of a line of space qualified, DSP based spacecraft computers (DSP modules) at Southwest Research Institute. The DSP module family (SC-DSP) established at Southwest Research Institute (SwRI) forms an integral part of SwRIs SC-9, VME based, command and data handling systems. Included in the SC-DSP line are the space proven TMS320C30 based, SC-7 module, several module variants of the RTX2010 processor, and a radiation tolerant version of the Analog Devices 21020 in the newest SC-21020 DSP module. SwRIs newest module (SC-21020) was developed to provide superior data handling functionality, while maintaining support for critical spacecraft control functions. The SC-21020 spacecraft computer utilizes these features coupled with high performance radiation hardened memories and the space proven VME bus. All together, the SC-DSP spacecraft computers have been space proven and used on several NASA and other missions. This paper addresses the evolution of SwRIs family of DSP based spacecraft computers, including the next generation of modules. Emphasis is placed on the advantages, tradeoffs, and applicability of high performance DSP spacecraft computers for space exploration. The performance and roadmap of the entire SC-DSP line is discussed in detail.

Leveraging flight heritage to new compactPCI space systems: a fusion of architectures

The advent of NASA-JPLs X2000 architecture has brought compactPCI (cPCI) to the forefront as the system bus of choice for space data processing. This paper presents a hybrid architecture allowing the inclusion of new, high performance cPCI modules with heritage VME-based modules. The hybrid system yields a cost-effective, performance optimized processing solution for space.

Leveraging flight heritage to new CompactPCI space systems: a fusion of architectures

The advent of NASA-JPLs X2000 architecture has brought compactPCI (cPCI) to the forefront as the system bus of choice for space data processing. This paper presents a hybrid architecture allowing the inclusion of new, high performance cPCI modules with heritage VME-based modules. The hybrid system yields a cost-effective, performance optimized processing solution for space.The advent of NASA-JPLs X2000 architecture has brought CompactPCI (cPCI) to the forefront as the system bus of choice for space data processing. This paper presents a hybrid architecture allowing the inclusion of new, high performance cPCI modules with heritage VME based modules. The hybrid system yields a cost effective, performance optimized processing solution for space.

VCSEL and Photodiode Proton Test Results for an Optical Communications Link

Proton irradiation results, including dose and single-event effects, for two vertical-cavity surface-emitting laser (VCSEL) diodes and a matching photodiode are presented. The optical components are part of a space instrument communications link for which the bit error rate was also measured during proton beam irradiation. A high-level description of the link hardware design and associated Manchester coding scheme is presented along with the beam test results.

GLAST Burst Monitor Signal Processing System

The onboard Data Processing Unit (DPU), designed and built by Southwest Research Institute, performs the high‐speed data acquisition for GBM. The analog signals from each of the 14 detectors are digitized by high‐speed multichannel analog data acquisition architecture. The streaming digital values resulting from a periodic (period of 104.2 ns) sampling of the analog signal by the individual ADCs are fed to a Field‐Programmable Gate Array (FPGA). Real‐time Digital Signal Processing (DSP) algorithms within the FPGA implement functions like filtering, thresholding, time delay and pulse height measurement. The spectral data with a 12‐bit resolution are formatted according to the commandable look‐up‐table (LUT) and then sent to the High‐Speed Science‐Date Bus (HSSDB, speed=1.5 MB/s) to be telemetered to ground. The DSP offers a novel feature of a commandable & constant event deadtime. The ADC non‐linearities have been calibrated so that the spectral data can be corrected during analysis. The best temporal reso...