IXV Ground Segment architecture status of implementation and testing

Transcription

1 SpaceOps Conferences 5-9 May 2014, Pasadena, CA SpaceOps 2014 Conference / IXV Ground Segment architecture status of implementation and testing I. Musso 1 and A. Bellomo 2 Advanced Logistics Technology Engineering Centre ALTEC S.p.A.,C.so Marche 79, Torino, Italy G. F. Santoro 3 Thales Alenia Space Italy, Strada Antica di Collegno 253, 10146, Torino Italy J. M. Gallego 4 European Space Agency HQ (LAU-PI) 52, rue Jacques Hillairet; Paris; France and IXV CSG ESA ASI NDIU AIT TM LCC LBC IFE TPVT MCC CCSDS R. Veneri 5 ALTEC S.p.A.,C.so Marche 79, Torino, Italy The Intermediate experimental Vehicle (IXV) is an ESA re-entry demonstrator aimed at performing in flight experimentation with guided atmospheric re-entry with launch from Kourou with Vega rocket, a quasi-equatorial sub-orbital trajectory followed by an immediate re-entry and splash down in the Pacific Ocean. The Ground Segment is composed by three Ground Stations connected via a satellite data links with the Mission Control Centre located in ALTEC. The last Ground Station is embarked aboard the ship necessary to recover the vehicle after the splashdown. The Ground Segment has been qualified during 2013 and it is now ready to support the mission operational readiness tests and the launch scheduled for late Nomenclature = Intermediate experimental Vehicle = Centre Spatiale Guyanais = European Space Agency = Italian Space Agency = Network Data Interface Unit = Assembly Integration and Test = Telemetry data = Launch Control Centre = Lab for Check-out room at CSG = In-Flight Experimentation data = Trajectory Propagation and Visualization Tool = Mission Control Centre = Consultative Committee for Space Data Systems 1 ALTEC Operations Manager, IXV Ground Segment System Engineer; ivano.musso@altecspace.it 2 ALTEC Scientific & Ground Applications Program Line Head, IXV ALTEC Program Manager; alessandro.bellomo@altecspace.it 3 TAS-I IXV Ground Segment Manager; gianfranco.santoro@thalesaleniaspace.com 4 ESA IXV & PRIDE System AIT & Ground Segment Manager; Jose.Maria.Gallego.Sanz@esa.int 5 ALTEC Engineering Operations Manager; ruggero.veneri@altecspace.it 1 Copyright 2014 by the, Inc. All rights reserved.

2 I. Introduction he Intermediate experimental Vehicle (IXV) is an ESA re-entry demonstrator aimed at performing in flight T experimentation with guided atmospheric re-entry. The main project objective is the on-ground and in-flight verification of an autonomous European lifting and aerodynamically controlled re-entry system. The key elements of the IXV mission are: launch from Kourou with VEGA toward the end of 2014, a quasi-equatorial suborbital trajectory followed by an immediate re-entry and splash down in the Pacific Ocean. The Ground Segment is composed by three Ground Stations connected, mainly via a satellite data link, with the Mission Control Centre located in ALTEC. The last Ground Station is embarked aboard the ship necessary to recover the vehicle after the splashdown. This paper details the IXV Ground Segment architecture and presents the most updated status of its implementation and testing activities. It provides special focus in the peculiarities of developing a Ground Segment for a suborbital/re-entry mission. The results of the last tests and verifications together with the activities related to the preparation of the mission, performed before the deployment of the Ground Segment, will be presented and discussed. II. IXV Mission Description The Intermediate experimental Vehicle (IXV) project objectives tackle the basic European needs for reentry from LEO, consolidating the knowledge necessary for the development of future European reentry systems while allowing risk limitation. A. Mission Objectives The project objectives are the design, development, manufacturing and on-ground and in-flight verification of an autonomous European lifting and aerodynamically controlled re-entry system. The re-entry technology experimentation focuses on verifying the performance of system-integrated advanced thermal protection and hot structures under realistic flight conditions. These include advanced ceramic and metallic assemblies, insulation, attachments, junctions and seals, as well as advanced guidance navigation and control techniques. This verification of performance in flight builds on previous efforts and ground verification, and aims at maturing the technologies for operational space applications. Re-entry technology validation focuses on gathering representative re-entry performance data in order to investigate aerothermodynamics phenomena and validate system design tools, evaluating the behavior of air around a lifting body for atmospheric entry in the hypersonic regime (above Mach 5). The most interesting phenomena stem from the behavior of the airflow around the vehicle, when the air molecules break apart to dissipate the high energies involved in re-entry and the perfect-gas laws are no longer valid. This complex situation affects the interaction between shockwave and boundary-layer flows, the interaction between shockwaves, the transition from laminar-to-turbulent boundary-layer flows, the transitional boundary-layer separation, the heating of thermal protection materials by turbulent boundary-layer flows, the overheating owing to external cavities, the behavior of materials catalytic properties, the materials oxidation, the reduction in efficiency of the control surfaces through boundary-layer flow separation, and the efficiency of the reaction control system. B. Involved Team and Responsibility The IXV project is an ESA Programme and the European Space Agency (ESA) is the final customer. Thales Alenia Space (TAS) is the Prime contractor and is responsible for the design consolidation, development and integration of the vehicle. TAS leads a team formed by major European industries, research centres and universities from several European countries. ALTEC has the responsibility for the development and management of the IXV Ground Segment, needed to provide all required capabilities for IXV mission support. The Ground Segment team is composed by ALTEC, that also holds the direct responsibility for the design, development and implementation of the Mission Control Center (hosted at ALTEC premises); TelematicSolutions (former Compagnia Generale per lo Spazio CGS) with the responsibility for the design, development and procurement of the Ground Stations; Telespazio (TPZ) that is responsible for the design, development and procurement of the communication network; Space Application Services (SAS) that provides the support for the operation of the Network Data Unit Interface (NDIU) to be used as 2

3 interface between the test and integration sites of IXV and the IXV Communication Network. In addition to this industrial organization, the participation of the ASI and CSG teams is ensured through ESA. C. Ground Segment General Overview The IXV Ground Segment design is composed of the following major elements: the IXV Mission Control Center (hosted at ALTEC premises), the IXV Ground Stations (located in Libreville, Malindi and aboard the Recovery Ship) and the IXV Communication Network. Ground Segment operations are constrained by several elements: 1) Safety: the IXV mission will make use of pyrotechnic devices and hydrazine propellant, which put strong constraints on the transportation of the vehicle, the operations during the launch campaign and the recovery operations. Safety is also constraining the trajectory, requiring a re-entry phase flight over unpopulated regions and a sea landing. 2) Trajectory: the re-entry phase flight over the unpopulated regions and the landing in the Pacific Ocean are limiting the possibilities of tracking, strictly related to TM Ground Stations availability. This requires mobile stations on ships. Also the recovery means are constraint by the sea landing, requiring a recovery boat with hooking and hoisting capabilities compatible with the vehicle. 3) Launcher: the IXV launch preparations will need to be coordinated with the VEGA launcher preparation activities in accordance to the CSG safety requirements and the VEGA User Manual; 4) Ground Segment components re-usability: three new ad hoc IXV kits have been procured to receive telemetry at the Libreville Fixed Ground Stations (shared with CSG) and at the Transportable Ground Stations (naval and island); these kits have been derived from Ariane 5 kits as and they have been tailored to IXV mission needs. The Malindi Ground Station equipments will be made available by ASI to the IXV mission needs. The Mission Control Center (MCC) development concept is based on the use of virtualization techniques. This solution has permitted to host the IXV MCC upon the existing ALTEC Mission Support Center infrastructure, operative since 2001 for ISS support, and to run in parallel the two virtualized environments. The MCC provides infrastructure, tools and applications to be used during the IXV mission for TM monitoring, storage, processing, displaying and detailed trajectory prediction. The MCC is the central node of IXV Ground Segment and it is interconnected with all Ground Segment elements, providing thus the required infrastructure for coordination and support, during IXV operative mission phase. The IXV Ground Stations grant the IXV space to ground communications, i.e. tracking the Spacecraft along its equatorial trajectory, receive and locally record TM and send selected data, in real time, to the Mission Control Center. The IXV Ground Stations Network concept is based (with exception of the Malindi Station) on the use of a transportable TM kit, that is attached to identified antennae (either reused from other Ground Station, like Libreville, or rented or procured for the program). The IXV Communication Network provides the necessary infrastructure to allow reliable communications between the IXV Mission Control Centre and the IXV Ground Stations, the AIT site (hosted in TAS Turin, IT) and the launch site (located at Guyana Space Center CSG, Kourou). The IXV Communication Network is IP based, and relies on satellite and terrestrial physical links for interconnecting its nodes. III. IXV Ground Segment Description IXV Ground Segment is composed by the following major elements: IXV Mission Control Center MCC (hosted at ALTEC premises), IXV Ground Stations (including one embarked on recovery ship) and IXV Communication Network. The MCC provides the infrastructure, the systems, the tools and the applications to be used during the IXV mission for Telemetry (TM) monitoring, storage, processing, displaying as well as detailed trajectory prediction and coordination of the Ground Segment operations; the Ground Stations grant the IXV space to ground communications, i.e. tracking the Spacecraft, receive and locally record TM and send requested data, in real-time and off-line mode, to the Mission Control Center; finally the Communication Network provides the infrastructure to allow communications between the IXV MCC and the GSs, the AIT site (Turin-IT) and the launch site (VEGA launch premises, in Kourou, Guyana Space Center CSG). 3

4 A. IXV ALTEC Misssion Control Centre The IXV Mission Control Center is hosted in ALTEC center premises (Centro Multi Funzionale Spaziale CMFS building), located in Turin, Italy. IXV MCC has been built-up using as much as possible infrastructures and services already in place for ISS ASI-PMM (Permanent Multipurpose Module) mission support center, with proper customization/adaptation for the IXV mission. To do so the whole ALTEC operation infrastructure has been moved to a virtualized environment, thus allowing the possibility to run, on the same HW, two separated and independent mission support systems. Adequate adaptations of network infrastructure have been implemented as well. MCC main purpose is to provide the relevant support environment for monitoring and storing the TM generated by the spacecraft. In particular the Vital Layer TM will be received and processed/displayed in real time while all the other telemetries, (e.g. delayed Vital Layer and IFE data) will be stored initially at Ground Stations and then retrieved by MCC as raw files. The ESA-MICONYS SCOS2000 has been adopted in order to provide such functionalities. This system has built-in functionalities for processing data and adopts standard used within the IXV project, such as Mission Database (MIB) definitions and CCSDS TM standard. Moreover the SCOS2000 offers seamless integration with ESA-MICONYS Network Interface System (NIS), that implements Space Link Extension (SLE) services in order to interface Ground Station TM data provision system. The IXV MCC has the responsibility to conduct and coordinate all IXV mission operations up to the complete recovery of the spacecraft on board the recovery ship and completion of the post recovery activities. In particular MCC will monitor IXV trajectory, coordinate Ground Stations operations and remotely support recovery. MCC will also host the Trajectory Propagation and Visualization Tool (TPVT) by means of which it will be possible, using real-time TM received from Ground Station in visibility, to perform spacecraft (S/C) trajectory propagation and to distribute it to the other Ground Stations, in order to ease the tracking of IXV, once in their visibility. Figure 1 - IXV Ground Segment Architecture B. Ground Segment Network The IXV Communication Network supports the real-time transmission to the IXV Mission Control Center of all real-time TM data sent by the IXV Ground Stations, as well as voice, trajectory data and other operational data types. IXV Communication Network is constituted by two main branches: AsiNet and INMARSAT network. AsiNet is an Italian Space Agency dedicated network that interconnects ALTEC and Malindi. This network is an in place reliable solution already validated and tested, whose services have been used by ALTEC MCC for many years to support other space missions. The other main branch of IXV network is constituted by Inmarsat satellite links. This network is used to interconnect MCC with TM- kit based Ground Stations. In particular the MCC is linked via leased line to the Inmarsat hub. Here network data is relayed to satellites and then received by Ground Stations Inmarsat terminals. 4

5 Finally test and launch sites are connected to MCC through dedicated ISDN links. The whole IXV Communication Network is IP based and makes use of standard transport protocols, e.g. TCP or UDP. C. Ground Stations IXV Ground Stations are in charge of tracking the S/C, receive and record TM and send it to MCC. Their locations are selected taking into account mission needs and thus arrangements at agencies level are made in order to reuse, where available, already existing facilities, up to an agreed extent (i.e. existing antenna with existing receivers or existing antenna to be fitted with one IXV TM system). IXV Ground stations, with the exception of Malindi, are based on the use of the TM kit. The IXV TM kits represent stand-alone apparatuses with respect to TM acquisition, demodulation and recording. This means that, once the kit is attached to a compatible antenna and to the required power source it becomes effectively a Ground Station capable to receive, store and forward IXV telemetry to MCC. The IXV downlink rate is 1Mbps for Vital Layer data and 1Mbps for IFE (Experiment) data both in S-Band. The Vital Layer TM stream is structured in different Virtual Channels (VCs) in line with CCSDS, allowing to separate different TM sources at the ground station. All Ground Stations are provided with recorders, in order to store all telemetry, both real time and delayed. Ground Stations will send to MCC all recorded data at a convenient time, as well as antenna azimuth and elevation pointing data recorded during the pass. The real-time MCC/TM-kit interface is managed through a dedicated tool that implements the CCSDS standard SLE-RCF specification for SLE data provision. This tool acts as SLE Provider and is able to forward to MCC only the required VCs in real-time, in order to comply with bandwidth constraints. Two different kinds of station are identified: Fixed Ground Stations and Transportable Ground Stations. The first fixed Ground Station located in Libreville is devoted to track the last stage of the Vega launcher, the AVUM. The separation of IXV takes place over Libreville. Both bodies are within the width of the Libreville antenna beam, making possible the reception of both telemetries from the same antenna. Thus, for IXV purposes, only the antenna at RF-level I/F and the power supplies are used by the IXV TM kit. The second fixed Ground Station located in Malindi (property of ASI) is CCSDS compliant and already provides interfacing system compatible with SLE standard. Malindi Ground Station, as well as ALTEC, is part of AsiNet and it is already interfaced with this network. During the initial phase of the project two additional transportable Ground Stations, fully allocated to IXV tracking, were considered. The two stations had to be setup from scratch, since no facilities are already available. In particular, the first was designed and built be located in an island in the Pacific Ocean while the second on the IXV recovery ship. The island ground station has been recently deleted due to the limited visibility provided by the final nominal trajectory. The naval Station is a Transportable Station installed aboard the recovery ship. The peculiarity of this configuration is that, in order to guarantee accurate antenna pointing, a stabilization system has been applied for compensating the attitude movement of the ship on the pointing of the antenna. To cope with the increased angular dispersion following the first part of the re-entry, this station also features an acquisition aid system, consisting of a dedicated scan aid feed, for enlarging the acquisition angle and to ease the S/C tracking and RF-lock by naval ground station. Those ground stations which require it are equipped with a program track system through which the vehicle propagated trajectory provided online by the MCC will be received and then converted in real-time into pointing values for antenna. Through this input the Ground Stations can start IXV pointing operations and once the signal is acquired the antenna can be switched to auto-tracking mode. IXV state vector, which is updated using information of the downlinked TM, is also continuously sent as a backup in case of loss of autotrack. Once IXV is locked the TM is received and stored. MCC, through the use of SLE protocol, automatically retrieves the desired TM in realtime. After S/C splash-down all recorded data are forwarded to MCC. IV. IXV Ground Segment Verfication The IXV Ground Segment team has just endend its qualifation and acceptance phase. The MCC and the three Ground Stations have been developed and tested to prepare for their deployment. Along the IXV Ground Segment development three verification levels and stages have been considered: 1) First all the Ground Segment subsystems have been verified after their detailed design and at the beginning of the development; these verification tests activities have been performed entirely at one single element level (i.e. network, MCC, telemetry kit, antenna, shelters); 2) Verification activities are then performed after the beginning of the integration of the Ground Segment including the first qualification process which is executed in a partially representative configuration; 5

6 3) When the Ground Segment is completely integrated and interfaced with the space segment the final verification tests, made to conclude the acceptance stage, are performed in a representative configuration and an operative environment. D. Subsystems Tests The first verification tests have been conducted during first half of First the MCC systems have been verified performing playback of telemetry files directly by MCC software systems in a stand/alone configuration. In parallel the first telemetry kit has been tested using its internal playback subsystem. In this way both MCC first software configuration and the telemetry kit prototype have been controlled in order to avoid any problem could be encountered during the development. Subsequently, thanks to an early deployment of the Telemetry Suitcase and the Inmarsat service, the test of the telementry kit has been repeated performing a first closed loop with the MCC. E. Ground Stations Verification Tests Extensive tests have been done for the verification of the Naval Ground Station in particular the antenna. At this stage the telemetry kit is partially integrated into the shelters, designed to host the systems during the mission and the naval antenna is integrated with the telemetry kit in order to receive the tracking data and elaborate the telemetry signal to be provided the MCC. A specific tracking campaign has been executed at factory against LEO satellites chosing the passages with a configuration similar to the one expected onboard the recovery ship during IXV mission in terms of radiofrequency, dynamics and pointing angles. The test equipments included also a wave simulator in order to operate the naval antenna in a representative environment and verify also its stabilization platform. Figure 2 - IXV Naval Antenna and ALTEC Mission Control Centre F. Integrated Operational Verification First Integrated tests have been executed during late 2013 and they had been repeated and continued during the first months of At the moment of wiritig this paper, the Ground Segment is already entirely available and first mission rehearsals have been executed involving also the ASI Malindi Ground Station and the ASINet network. During those tests the MCC has proven to be ready to manage the four ground stations originally considered (three telemetry kits plus Malindi ground station) under real operative constrains. 6

7 From the flight segment side the first SVT took place during the same period with the involvement of the ALTEC MCC. The IXV integration proceeds and the spacecraft is mature enough to provide extensive samples of telemetry files to be provided to the Ground Stations for playback. Integrated tests have allowed the first definition of mission procedures to be further refined during the Ground Segment deployment. Some training sessions also took place both at the Mission Control Centre, to allow flight operators to learn about the systems and display available at their consoles, and for the Ground Station, in order to exercise the operations of the naval antenna as well as the telemetry kits. It has to be noted that the Ground Segment mission team will be mainly composed by the engineers and technicians responsible of the development integration and tests of the entire system. Under this assumption we did not plan for intensive training sessions due to the fact our team is already trained to operate most of our devices under nominal and contingency conditions. Integrated and operational tests will continue during the second quarter of 2014 until start of the Ground Segment deployment in order to further define ground procedures and support the development and verification of the flight segment. V. IXV Ground Segment Deployment Plan The deployment of the Ground Segment will be executed during the second half of 2014, starting almost three months before the IXV launch. The deployment is divided into four phases partially overlapping: 1) Deployment Phase 1: Libreville installation and verification, naval station pre-installation 2) Deployment Phase 2: Naval station final verification and ship crossing to the recovery area 3) Ground Segment Operational verification 4) Launch preparation A. Deployment Phase 1 One of the telemetry kit is shipped to the Libreville ground station to be installed and integrated with the S-Band antenna devoted to the tracking of the Vega/IXV mission. After the installation a SLE Acceptance Test is performed using the telemetry file recorded from the flight segment during the last SVT planned for mid After a complete test session with the MCC, the Libreville Ground Station will be considered ready to support the IXV mission. During the same period part of the naval ground station will be installed onboard the recovery ship in Italy. This first part of the integration will include all the cablings and the support equipments necessary to host the ground station. Part of the electronic equipments could be installed too. B. Deployment Phase 2 Less than two months before launch the naval ground station will be installed, including the S-Band antenna. The recovery ship will also host all the equipments necessary to execute the recovery of IXV from the sea and, under the Ground Segment direct responsibility, a meteo station to execute meteorological radio-soundings necessary to correctly forecast IXV trajectory. Test sessions will also be performed with the MCC, including some tracking campaigns with LEO satellites. Then the ship will be ready to weigh anchor across the Atlantic and toward the Pacific Ocean, to the area of the IXV's splashdown. The crossing is expected to last more than forty days. C. Ground Segment Operational verification Just after the standalone tests of the naval ground station at the departure harbor, a further integrated tests of the Ground Segment will be executed. This final verification will have the scope to demonstrate the readiness of the Ground Segment to support the mission and it will provide a further training session for a complete mission rehearsal. All the three ground stations will be on the loop, including the ASI Ground Station of Malindi. The flight team is also expected to be hosted at the MCC during this event in order to execute a final and complete verification of the ground procedures. 7

8 D. Launch preparation During the travel of the recovery ship, the IXV spacecraft will be already arrived at the CSG launch facility CSG in Kourou. From Torino the MCC will be involved during the verification of the spacecraft, providing a remote support during the on-site activities. Almost two weeks before launch the Ground Segment teams responsible for the operations of the ground stations will depart from Italy to Libreville and Panama, to join the recovery ship at its arrival at the passage across the two Oceans. A final mission rehearsal will be execute few days before launch when the recovery ship will be near the recovery area or already there. This will be probably the last event planned to refine the mission procedures and timelines for the Ground Segment. VI. IXV Timeline and Operations The day of the Launch the spacecraft will be switched on almost 4 hours before lift-off to repeat a certain number of functional checks, the monitored TM data will be accessible remotely both by the IXV team in the GSG and by the ALTEC IXV Mission Control Center, through the NDIU, in order to support opportunely the launch phase. The IXV Operations team will have a position at the Launch Control Center that will act as a go-between the IXV MCC and the Launch director and between the IXV MCC and the IXV team in the CSG integration rooms. Links between the IXV MCC and the Operations position at the LCC, and between the IXV MCC and the LBC room will be setup in order to allow voice connection and data exchange. The first part of the flight (orbital phase starting from the separation event) will be covered by the Ariane 5 tracking station of Libreville (Gabon) and, in addition, the use of an IXV dedicated antenna at the Malindi Ground Station is planned. These two fixed Ground Stations network will grant coverage of more than 10 minutes in order to acquire data on the spacecraft status and start a system/subsystem health monitoring and acquire navigation data to feed the trajectory simulator at the MCC. In fact during the mission a continuously updated prediction of the whole trajectory will be performed by the TPVT trajectory simulator, hosted at the MCC. After the Malindi Ground Station and during the black-out phase, the trajectory predictions will be used to generate the pointing data for the embarked antenna. At last, using the IXV navigation data and the meteorological data coming from the Recovery Ship, a more accurate prediction of the descent trajectory and of the splash-down point will be produced. The entry gate (defined conventionally with the crossing of 120 km altitude) is considered the starting point for the main experimentation. During the black-out phase the data continue to be stored on board in the redundant recorders and transmitted to ground even if signal reception is lost. The start and end altitudes conventionally considered for the black-out are almost 90km and 50km respectively. The mobile Ground Station installed on board the Recovery Ship will receive from the MCC online trajectory data for its correct pointing and the antenna will track the spacecraft using auto-tracking capabilities and its stabilization system to compensate the effects of swell. In order to allow the complete downlink of all the data recorded during the black-out phase, the transmission will continue, therefore the link will be maintained until the antenna installed on board the recovery ship loses the visibility due to the fact that IXV, approaching the sea, goes below its line of sight. Finally the spacecraft will be localized and recovered. VII. Conclusion The IXV Ground Segment has finished its development and qualification phase. The operational verifications have started and the deployment is scheduled to start during the second half of We have proven the capability of our industrial team to provide the support for a test reentry mission. References 1 G. Martucci, A. Bellomo, I. Musso, G. Santoro, G. Billig, The IXV Ground Segment: Design, Architecture, Operational Development and Testing Status, ARA Atmospheric Reentry Association 2013 Conference, May , Arcachon, France 8