ALTEA data handling

Advances in Space Research 37 (2006) 1710–1715 www.elsevier.com/locate/asr ALTEA data handling L. Di Fino a, F. Belli a, V. Bidoli a, M. Casolino a, L. Narici a,*, P. Picozza a, A. Rinaldi a, D. Ruggieri a, V. Zaconte a, S. Carozzo b, W.G. Sannita b,c, P. Spillantini d, V. Cotronei e, E. Alippi f, G. Gianelli f, A. Galper f, M. Korotkov g, A. Popov g, V.P. Petrov h, V.P. Salnitskii h, S. Avdeev i, W. Bonvicini j, G. Zampa j, N. Zampa j, R. Vittori k, C. Fuglesang l, D. Schardt m a INFN and University of Rome Tor Vergata, Department of Physics, Via della Ricerca Scientifica 1, 00133 Rome, Italy b Neurophysiopathology-DISM, University of Genoa, Genoa, Italy c Department of Psychiatry, SUNY, Stoony Brook, NY, USA d Department of Physics, University and INFN, Florence, Italy e Italian Space Agency, Rome, Italy f Alenia Spazio S.p.A. – Laben, Milan, Italy g Moscow State Engineering Physics Institute, Moscow h Institute for BioMedical Problems, Moscow, Russia i Cosmonaut, Russian Space Corporation ÔEnergiaÕ by name Korolev, Korolev, Moscow region, Russia j Department of Physics, University and INFN, Trieste, Italy k ESA Astronaut and INFN, Perugia, Italy l ESA Astronaut, Royal Institute of Technology, Stockholm, Sweden m GSI/Biophysik, Darmstadt, Germany Received 14 October 2004; received in revised form 21 January 2005; accepted 31 January 2005 Abstract The ALTEA program is an international and multi-disciplinary collaboration aimed at studying particle radiation in space environment and its effects on astronauts, in particular the anomalous perception of Light Flashes. This paper describes ALTEA space facility scheduled to fly in the International Space Station (ISS) after July 2006, what kind of data are produced and how data are transmitted to Earth, processed and analyzed. Ó 2006 Published by Elsevier Ltd on behalf of COSPAR. Keywords: ALTEA; Cosmic rays; Data handling; ISS; Light flash Abbreviations: ALTEA, Anomalous Long Term Effects on Astronauts; ASI, Italian Space Agency; ASMP, Asymmetric MultiProcessor; BEU, Brain Explorer Unit; BNL, Brookhaven National Laboratory, Upton, NY, USA; CNSM, Central Nervous System Monitoring; DAU, Data Acquistion Unit; DOMSAT, Domestic Satellite; DOSI, Dosimetry; DSP, Digital Signal Processing; EEG, ElectroEncephaloGraph; GSI, Institute for Heavy Ion Research, Darmstadt, Germany; HIT, Heavy Ion Therapy; ISS, International Space Station; LET, Linear Energy Transfer; LOR, Line Outage Recorder; LTU, LapTop Unit; MARS, Microgravity Advanced Research and Support; MICE, Mice Irradiation with Concurrent Electrophysiological monitoring; MIP, Minimum Ionizing Particle; MSFC, Marshall Space Flight Center; OBT, On Board Time; PBU, Push Button Unit; POIC, Payload Operations Integration Center; RIC, Rack Interface Controller; SDS, Silicon Detector System; SDU, Silicon Detector Unit; SGS, Space-to-Ground Subsystem; SSCC, Space Station Control Center; TDRSS, Tracking and Data Relay Satellite System; UHB, User Home Base; USOC, User Support and Operation Center; VSU, Visual Stimulator Unit; WSC, White Sands Center. * Corresponding author. Tel.: +39 0672594519; fax: +39 062023507. E-mail address: [email protected] (L. Narici). 0273-1177/$30 Ó 2006 Published by Elsevier Ltd on behalf of COSPAR. doi:10.1016/j.asr.2005.01.105 L.D. Fino et al. / Advances in Space Research 37 (2006) 1710–1715 1. Introduction The length of manned space flights (operations in the International Space Station (ISS) or the planned journey to Mars) will significantly increase in the near future. Anomalous Long Term Effects on Astronauts (ALTEA) is an international and multi-disciplinary program aimed at studying the effects of particle radiation on the Central Nervous System during long manned missions on board ISS, in particular the anomalous perception of Light Flashes (Casolino et al., 2003). ALTEA includes a space facility scheduled to fly and operate in the ISS after July 2006 (Narici et al., 2003). This paper describes what kind of data are produced by this facility and how data are transmitted to Earth, processed and analyzed; it consists of five main sections. In the first section a quick overview of the apparatus and its main scientific objectives are presented. The second section deals with different experiment configurations and data produced during ALTEA space experiments. Third section is about audio and video requirements. Fourth section describes in details data path during transmission from ISS to ALTEA User Home Base (UHB) in University of Rome Tor Vergata. Last section gives a hint about processing and analysis of ALTEA scientific data. 1711 sponses to proper visual stimuli will permit to assess the visual system status. It will also operate in unmanned mode to allow long term measurement of particle fluxes inside the ISS. The ALTEA facility (see Fig. 1) is composed by:  Data Acquisition Unit (DAU)  Silicon Detector System (SDS) – composed by 6 particle detectors (SDU)  Brain Explorer Unit (BEU) – 32-channel ElectroEncephaloGraph (EEG)  Visual Stimulation Unit (VSU)  Push Button Unit (PBU)  LapTop Unit (LTU) The Data Acquisition Unit (DAU) is connected with the 6 Silicon Detector Units (SDU) and with the Visual Stimulation Unit (VSU). The DAU and the LapTop Unit (LTU) are connected via TCP/IP with the ISS using the Rack Interface Controller (RIC) connections. ALTEA is an autonomous experiment from the point of view of the interaction with Ground: no remote control is foreseen and just an initial and guided participation of the astronaut to experiment set-up is required. All data from ALTEA are in the form of Express Rack Teleme- 2. ALTEA facility: general description ALTEA is a multi approach program. It consists of various experiments both laboratory based and onboard ISS. Ground experiments are:  ALTEA-MICE (Sannita et al., 2004): started in 2001 at GSI and BNL  ALTEA-HIT: started in 2004 at GSI  ALTEA-Biophys: started in 2003 at GSI Space experiments are:  Alteino (Casolino et al., 2002): onboard ISS since April 2002  ALTEA Light Flash Questionnaire (Fuglesang et al., 2004): started in 2003  ALTEA-Space: scheduled to fly in December 2005  Other future uses of the ALTEA Facility (ALTEA3D, ALTEA-Shield, etc.) ALTEA-Space will measure on board ISS the particles passing through the brain of the astronauts and monitor the cortical electrophysiological activity and the visual system functional status. The goal is to define and measure electrophysiological descriptors of brain functioning and to correlate their dynamics with space environments (Narici et al., 2004). Measures of re- Fig. 1. Schematic view of ALTEA facility: it is possible to see all ALTEA devices attached to Express Rack during CNSM mode; technical specifications are given for each component. In the upper left corner a 3D view of ALTEA inside ISS. 1712 L.D. Fino et al. / Advances in Space Research 37 (2006) 1710–1715 for the whole increment is about 1.3 Tb. Second operative mode is CNSM. Six 90-min sessions are planned as follows: an astronaut will wear the EEG cap, insert his/ her head in the SDS and will signal perceptions of Light Flashes with a pushbutton while SDS will measure cosmic rays flux through his head, so that it will be possible to study concurrently the passage of cosmic radiation through the brain, the functional status of the visual system and the electrophysiological dynamics of the cortical activity. Data are stored on the ISS laptop. Expected data rate is 1.4 Mbps and each session is expected to take up about 1.5 Gb. Data are then downloaded off-line and erased from the laptop only after positive transmission check. Table 1 Structure of an Express Rack Telemetry packet 4. Audio and video Table 2 Telemetry data: main data types are reported together with packet size and frequency of acquisition Telemetry data type Packet size (bytes) Frequency of acquisition Science SDS data Service data Nominal housekeeping EEG data Health & status 122–1266 24 232 1074 34 Event driven Event driven 10 Hz 1024 Hz 1 Hz try packets. In Table 1 the structure of a telemetry packet is described. In Table 2 various kinds of telemetry data are reported together with packet length and frequency of acquisition. Scientific telemetry data and service data generation depend on instrument operating mode and on involved subsystems. SDS generates periodic scientific data only in calibration mode, otherwise data generation is triggered by particle detection. To assure optimal setup of the experiment, real-time audio and video communications are required. The audio will be a bidirectional system, while video will be a one-way system from ISS to earth. Fig. 2 shows a schematic view of experiment timeline in which audio and video communications are reported: we asked for recorded video during the entire system setup and during CNSM setup, while realtime video and audio will be used only in the last 10 min of system setup and the first 15 min of CNSM setup. A second astronaut will help the subject during part of the CNSM sessions. 5. ALTEA data flow This section deals with transmission of data from the Payload on board ISS to the ALTEA UHB, where data are stored and analyzed. Composition of Space Segment and Ground Segment are described together with Transmission Bands used for communications and data distribution between different segments. In Fig. 3 there is a block view of the entire data flow. 3. Experiment configurations and expected data rates 5.1. Space data segment The two main ALTEA-Space configurations are named Dosimetry (DOSI) mode and Central Nervous System Monitoring (CNSM) mode and they are, respectively, unmanned and manned operative modes. ALTEA will continuously operate in DOSI mode for a period of one increment without human intervention. There will be six interruptions corresponding to the CNSM sessions. During DOSI mode ALTEA measures radiation fluxes on board ISS. Only Silicon Detector System (SDS) is switched on and data are downloaded in real-time, without any local storage. Expected data rate is about 0.65 Mbps, so the estimated storage size 5.1.1. Onboard ISS ALTEA is installed in an Express Rack, that provides standard and simple interfaces to payloads, and it communicates over a local LAN to the RIC. The RIC is configured as a passive server and provides the communication link between payloads and the Space Station data system and ground controllers. The RIC will route the payload data in packets (Express Rack Packets), with headers to identify the payload (see Table 1), and it will transmit them through the Space Station data system. All communications onboard ISS are based on TCP protocol. L.D. Fino et al. / Advances in Space Research 37 (2006) 1710–1715 1713 Fig. 2. Schematic view of ALTEA experiment timeline: it is possible to see recorded video during the entire system setup and realtime video and audio communications during part of the setup. Fig. 3. Schematic view of ALTEA data flow: data are produced by ALTEA facility on board ISS (Section 5.1.1), then transmitted through TDRSS and WSC (Section 5.1.2) to NASA Ground Segment (Section 5.2.1) and finally to Italian Ground Segment (Section 5.2.2). 5.1.2. TDRSS and WSC All ISS communications to Earth are vehiculated by Tracking and Data Relay Satellite System (TDRSS). TDRSS consists of 6 satellites in geosynchronous orbits and a dedicated ground station. The main task of the TDRSS is to provide communication and tracking services for ISS and other low-earth orbit spacecrafts. TDRSS operates as a repeater, relaying signals to and from the ground station. No data processing is done onboard the TDRSS. The ground station that monitors and controls the satellites is the White Sands Ground Terminal in New Mexico. White Sands Center (WSC) has a Line Outage Recorder (LOR) that records data in case a connection between WSC and one of the NASA centers fails. If that happens, WSC can play back the data when the connection is restored. 5.1.3. Data transmission bands Transmission Bands used for communications and data distribution between Space Segment and Ground Segment are S-band and Ku-Band. S-band data is relayed to/from ISS via TDRSS. S-Band carries primarily core system data down and 1714 L.D. Fino et al. / Advances in Space Research 37 (2006) 1710–1715 commands up. S-Band operates at 2065.0 and 2085.6875 MHz and it is used for the forward and return link to ISS. Ku-Band is used as a return data link and data is sent from the ISS Space-to-Ground Subsystem (SGS) to White Sands via TDRSS. Data are then sent to the control centers, and finally to remote users. Ku-Band operates at 13,775 and 15003.4 MHz and primarily carries High Rate Payload Data, Digital Video (video is converted from analog to digital onboard and sent down as a part of the Ku-Band data) and Core Playback Data. 5.2. Ground data segment 5.2.1. NASA ground segment The two main nodes of NASA Ground Segment are Space Station Control Center (SSCC) at Johnson Space Center and Payload Operations Integration Center (POIC) at Marshall Space Flight Center (MSFC). Planning and procedure data are exchanged between SSCC, POIC and the Italian Ground Segment. Audio coordination is used between sites on the ground. The POIC is responsible for scheduling, managing, and controlling the Space Station onboard payload data and video systems. ALTEA data is received at MSFCÕs POIC that has the overall responsibility for payload ground data distribution. At MSFC there is also the capability to monitor vital payload information. Beside ALTEA scientific data, other kind of data will be distributed: ISS System Telemetry, Air-to-ground Audio and Air-to-ground Video. Data are distributed to remote sites using UDP protocol. 5.2.2. Italian ground segment Data are transmitted to Italian Segment from the Italian Space Agency (ASI) Gateway (USA) through the ASI-Net backbone to the Microgravity Advanced Research and Support (MARS) Center in Naples that operates as ASI Italian User Support and Operation Center (USOC) and that is responsible for the operations of the Italian Payloads onboard ISS. Finally data reach ALTEA UHB. 5.2.3. ALTEA UHB ALTEA UHB will be able to monitor experiment, to store and to analyze collected data. UHB configuration will be the following (see Fig. 4): (1) One Data Storage Server (with redundant disk array). (2) One or more multi-processor workstation for Scientific Data Analysis. (3) One Video-Conference workstation for video-conference communications with NASA. (4) One Voice-Loop workstation for audio-communications with ISS. (5) One wide screen monitor/video projector to display ISS real-time video or scientific data. We are considering the use of multi-processor Linux workstations with specially developed Asymmetric MultiProcessor (ASMP) real-time kernel and dedicated Digital Signal processing (DSP) boards for real-time analysis. ASMP kernel allows to entirely dedicate one or more processor to specific tasks, reducing overhead due to standard system operations. Fig. 4. Schematic view of ALTEA UHB: it is possible to see the structure of the User Home Base with the private LAN, the analysis workstations, the storage server and the devices for communications and data presentation. L.D. Fino et al. / Advances in Space Research 37 (2006) 1710–1715 6. ALTEA data analysis 6.1. DOSI analysis In DOSI mode Health & Status and Housekeeping data such as voltages, currents and temperatures will be monitored to ensure proper functioning of all the instrumentation and to allow emergency deactivation or to shut down any system or subsystem. Off-line analysis of scientific data will be able to process scientific data relative to SDS subsystem, performing pedestal subtraction, adaptive pedestal correction, bad data rejection, particle track reconstruction, released energy calculation, Linear Energy Transfer (LET) calculation, nuclear species discrimination, relative and absolute nuclear abundances calculation, differential and integral radiation fluxes calculation and statistics on particle direction. In addition to this some ancillary data of the ISS (position, altitude and inclination) will be correlated with ALTEA data to obtain information about radiation fluxes in different geomagnetic zones. Work is in progress to process a subset of these operations in real-time, in order to issue space radiation warnings to the crew. 6.2. CNSM analysis In CNSM mode, all subsystems will be switched on, and in addition to previous ones there will be data from EEG and Push Button Unit (PBU). CNSM data will be analyzed off-line to measure the energies and trajectories of the cosmic particles passing through the astronautÕs 1715 brain concurrently with his brain electrophysiological dynamics. Particle trajectory and absorbed doses in brain will be calculated and the correlation between the energy released in different cortical regions and changes in the electrophysiological signal will be studied. This will allow to define new risk parameters linked to the interaction in space between ion passages and brain functions. Acknowledgement ALTEA is funded by the Italian Space Agency. References Casolino, M. et al. The Sileye-3/Alteino experiment on board the International Space Station. Nuclear Physics B 113B, 71–78, 2002. Casolino, M. et al. Dual origins of light flashes seen in space. Nature 422, 680, 2003. Fuglesang, C., et al. Astronaut Light Flash Survey. ESA Report MSM-AM-AHC-GNC-RP-001, 2004. Narici, L. et al. ALTEA: Anomalous long term effects in astronauts. A probe on the influence of cosmic radiation and microgravity on the central nervous system during long flights. Advances in Space Research 31, 141–146, 2003. Narici, L. et al. The ALTEA/Alteino projects: studying functional effects of microgravity and cosmic radiation. Advances in Space Research 33, 1352–1357, 2004. Sannita, W.G. et al. Effects of heavy ions on visual function and electrophysiology of rodents: the ALTEA-MICE project. Advances in Space Research 33, 1347–1351, 2004.