The MSG satellite architecture
The spacecraft commissioning activities were concluded at the end of March and a comprehensive report has been compiled by the ESA/Matra Marconi Space team in charge of this phase.
A very important achievement during the commissioning phase was the solution of a problem with the VIRGO instrument, one of the covers of which had been repeatedly rebounding back to its closed position when commanded open. Analytical simulations and parallel tests on the ground with the experiment flight-spare units confirmed a previously undetected sensitivity to particular parameters. A joint effort involving the experiment's Principal Investigator and the ESA and industrial teams produced a solution to the problem involving temporary modification of the central onboard software. The modified procedure worked as foreseen and the reluctant cover was finally opened on 27 March.
On 16 April, the SOHO mission was handed over to the ESA-led scientific team, most of whom are currently based at Goddard Space Flight Center (NASA/GSFC) in Maryland (USA).
A Press Conference was held at ESA Headquarters in Paris on 2 May to present the excellent first results from SOHO and to publicise the opportunities that this mission offers for the advancement of solar physics. During May, the flow of scientific observations has reached the planned level, with several joint observing operations already in progress in which various SOHO instruments, ground-based observatories and other spacecraft are cooperating.
The Meteosat Transition Programme (MTP) spacecraft has now been fully mechanically integrated and electrically tested. The acceptance-level environmental tests are scheduled to take place in the autumn. Launch, on an Ariane-4 vehicle, is planned for the beginning of July 1997. The MTP spacecraft will be the last of the Meteosat Operational programme (MOP) design to be launched.
Once launched, the spacecraft will be operated by Eumetsat to provide the regular weather pictures over Europe which are currently being provided by Meteosat-5, with Meteosat-6 as the in-orbit spare, these two spacecraft having also been built under ESA spacecraft supply contracts.
The MSG satellite architecture
The MSG main development phase (Phase-C/D) was concluded in April with the final system-level Preliminary Design Review (PDR), as planned. Engineering-model manufacture and thermal/mechanical-model manufacture have been released to industry, except for the telescope and scan assembly of SEVIRI (the Spin Enhanced Visible and Infra-Red Instrument) which, in order to be compatible with both the launch and the in-orbit thermal environments, needs redesign. A supplementary PDR is now planned for October, which puts the SEVIRI schedule on a critical path.
Negotiations with industry for the procurement of the three satellites MSG-1, 2 and 3 have been concluded. Launch of MSG-1 is now scheduled for October 2000, with MSG-2 to be launched in 2002 and MSG-3 to go into storage (as a backup) in 2003.
Eumetsat is contributing a fixed amount to the ESA MSG-1 development programme, but is fully financing MSG-2 and MSG-3, which are being procured by ESA on Eumetsat's behalf.
Industrial activities have resumed following a holding phase introduced after the Preliminary Design Review. Competitive selection of subcontractors for new equipment has started with the aim of achieving a consolidated set of designs and interfaces as quickly as possible.
The ASCAT demonstrator activities have been completed and the instrument'design is in an advanced stage and ready for the start of Phase-C/D.
The generation of Instrument Interface Control Documents has progressed considerably and has generally reached an appropriate degree of maturity.
The METOP Programme Proposal and Declaration and the ESA/Eumetsat Cooperation Agreement have been debated within the framework of Potential Participant Meetings, and also in direct discussions with Eumetsat. Considerable progress has been made in refining their content.
As the METOP Phase-C/D Programme Declaration cannot enter into force prior to the end of the present industrial Phase-B, a Phase-C0 has been proposed to the Participating States. This includes the continuation of industrial activities orientated towards the initiation of long-lead-item procurements, considered essential if the envisaged development schedule is to be maintained.
The ERS-1 payload was put into hibernation on 3 June. SAR imaging is still being conducted for an average of two passes per day over Kiruna (S) for interferometry purposes. The payload will be reactivated every second 35-day repeat cycle for 3 days to perform maintenance activities.
ERS-2 has completed its first year in orbit. Some minor anomalies have occurred on the Active Microwave Instrument (AMI) and the Radar Altimeter (RA), leading to data interrupts. The ATSR-2 instrument has suffered a major anomaly in its scanning mechanism which has interrupted its operations, and this problem is still under investigation.
The Global Ozone Monitoring Experiment (GOME) continues to demonstrate stable performance. A minor problem in the complex ground-processing system has delayed the distribution of data to the full user community, but this is expected to be completed by July this year. GOME's operation and data gathering has been somewhat affected by the continuing investigations into the ATSR- 2 anomaly. It is hoped both to obviate this adverse impact on the GOME and to recover the operation of the infrared radiometer by means of a software change. The PRARE instrument continues to operate nominally.
All ERS-2 spacecraft performances remain stable. An extension of ERS-2 operations until the expected Envisat launch date has been proposed to the ESA Delegations.
The period under review has seen a number of significant achievements that reflect the continuing successful progress of the overall Huygens project and Cassini mission.
The Critical Design Review action-item close-out meeting reviewing all actions including those relating to the External Independent Readiness Review and the Hardware Readiness Certification Review (HRCR), both with the participation of NASA/JPL, were successfully carried out during March. The HRCR in particular led to the approval to ship the engineering-model Probe to the USA for subsequent integration and combined testing with the Cassini spacecraft.
Also during March, a Ground Segment Implementation Review (GSIR) was held at ESOC (D), which showed that the state of implementation readiness for both hardware and software was fully satisfactory. The engineering-model Probe was subsequently shipped to JPL during April.
Integration and interface testing with Cassini was also completely satisfactory, as too was the running of the Probe in- orbit checkout sequences. These tasks, accomplished by a combined ESA/industry team, proved the integrity of the Probe, allowing it to be left at JPL, with just a very small supporting industrial team, for future combined Orbiter/Probe activities.
Flight-model Probe integration and testing has progressed successfully, even though some experiment units are currently 'non-flight'. The extra work brought about by late experiment deliveries/model exchanges, etc. has had an impact on the schedule, causing the Flight Acceptance Review to be shifted to February 1997. This does not endanger the launch date.
By the end of May, preparations were well in hand for the major system tests, the thermal-vacuum and Titan entry cold test.
Qualification model of the XMM mirror module
Following the successful Preliminary Design Review (PDR) last November, the data package for which also constitutes the technical proposal for the XMM Main Development Phase (C/D), the financial proposal was submitted and evaluated. The results and recommendations were presented to the Agency's Industrial Policy Committee (IPC), which approved the programme's implementation at its meeting on 15 March.
The contract to build the XMM spacecraft, due for delivery on 1 June 1999, was signed with Dornier Satellitensysteme GmbH, the prime contractor, on 21 March.
The adoption of a new management style with more direct communication between the various levels has had a positive effect in holding the schedule.
The design of the experiments, three X-ray cameras, two reflection grating spectrometers and an optical monitor, is complete, with very good performance predictions. Testing of electrical models of the instruments is in progress. X-ray testing with the qualification-model mirrors is foreseen for the autumn.
The development of the X-ray mirrors, under ESA's direct responsibility, is proceeding as planned. The qualification model of the complete mirror module, consisting of 58 nested mirrors, has successfully completed EUV and X-ray testing, as well as vibration and thermal tests. The first flight-model spider has been manufactured, and the next three are well advanced. Approximately a quarter of the 232 flight mirrors have been produced and the metrology indicates that they are of good quality.
The XMM service module is designed for commonality with Integral. Long-lead items have been ordered in 1995, and the PDRs for the spacecraft units are now being conducted. The electrical models are in production, to be delivered at the end of the year, and manufacture of the structural models has commenced.
The prime contractor for the spacecraft, Alenia Spazio (I), has continued its definition work, with the boundary condition of commonality with the XMM service module. In parallel, it has evaluated, jointly with the Agency, the proposals received in response to competitive Invitations-to-Tender for Integral- specific items. The results of these actions will be reflected in the Preliminary Design Review data package and the Phase-C/D proposal to be submitted in early June.
The first review of the payload has been completed, resulting in agreed instrument-to-spacecraft technical interface definitions.
Turning to the ground segment, a similar review process was initiated for the Science Data Centre that will process Integral's instrument data. The remainder of the ground-segment effort has focussed on the definition of implementation plans in response to project requirements.
Model of Artemis spacecraft
Satellite
The primary structure of the structural
model (SM) has been delivered to BPD in Colleferro (I), for
integration of the SM propulsion subsystem and instrumenting of
those elements that will be inaccessible later. This activity,
which also involves CASA (E) and Alenia (I), is planned to be
completed by the beginning of July this year. The SM primary
structure will then be returned to CASA in Madrid for final
assembly and preparation for shipment to ESTEC, where it will
start its environmental test campaign at the end of August.
The engineering-model (EM) assembly, integration and test campaign has started in the ALS facilities. To avoid duplication of the integration and dismounting of panels from the payload dummy support structure to the EM, the S-band/Ka-band Data Relay (SKDR) payload has been integrated directly on the spacecraft. The Test Readiness Review (TTR) of this activity was successfully completed at the end of May.
By using this approach, the SKDR payload test campaign is being performed in parallel with the integration and testing of the platform subsystems. Integration and testing of the Power Control and Distribution Subsystem (PCD), elements of the ion- propulsion subsystem, and inter-face verification with the onboard data-handling bus are currently in progress.
Ground segment
A proposal to merge the Artemis
ground segment with the satellite's main development phase (C/D)
contract was approved by the Agency's Industrial Policy Committee
(IPC) on 8/9 May.
The scope of this contract, which is the responsibility of ALTEL as a subcontractor to Alenia, is:
Indra Espacio (E) is the main contractor for the Primary TTC Station's design, development and system assembly, integration and testing, with Rymsa (E) as subcontractor for the antenna subsystem and Laben (I) for the baseband subsystem. Equipment suppliers include ERA (UK) and MAC (I).
Nuova Telespazio is responsible for the design and development of the operations control centres, operations preparation and execution. The subcontractors include Dataspazio (I), GMV (E) and ELCA (CH) for the OCC software.
Telespazio will also receive direct technical support and consultancy services from ESOC.
Silex LEO terminal
Integration of the Silex LEO
flight terminal is proceeding well. Environmental testing will
start in mid-July and will be completed before the end of the
year.
The testing of the engineering-model (EM) terminal together with the Spot-4 EM spacecraft has produced excellent results. In particular, the EMC tests have shown that no corrective actions need to be implemented.
Tests to demonstrate correct operation of the Silex EM terminal on Spot-4 together with the Spot-4 ground segment and the Silex ground segment in Redu (B) are currently underway.
Future programmes
Nine 'Reports for Assessment'
(ESA Special Publication SP-1196, Vols. 1-9) on the agreed
candidate Earth Explorer missions were issued in April. These
documents, established with the support of Mission Working Groups
and industrial studies, formed the basis for a wide consultation
with the European Earth Science Community, which culminated in
the Earth Explorer Mission Users Consultation Meeting in Granada
(E) on 29-31 May.
The future extension of EOPP beyond mid-1996 continues to be discussed with Delegations.
Campaigns
Preparations for the INDREX-96 campaign,
which is aimed at development of a 'Remote Sensing and Monitoring
System for Forestry Management and Land Cover in Indonesia', are
now well advanced.
Polar Platform (PPF) The Polar Platform activities have progressed in three basic areas:
In addition to the above model-oriented activities, a significant managerial and engineering effort has been devoted to identify descoping opportunities in nonessential activities in order to reduce costs. These efforts have allowed appreciable cost savings to be achieved, albeit with a slightly increased development risk. In addition, funding limitations imposed by Delegations have resulted in a need to renegotiate payment conditions with industry.
Envisat-1 payload
The structural-model programme
has seen significant progress in the last few months, with an
increasing number of tests at unit and assembly level being
successfully completed.
A reinforcement of the main structure for ASAR and MERIS has been implemented, and both instruments have successfully passed their qualification tests. All instrument structural models are now integrated on the Polar Platform structural-model spacecraft, ready for environmental testing in the ESTEC facilities.
Structural model of the MERIS instrument during vibration
testing
Polar Platform structural model in the ESTEC test facilities
As far as the engineering-model programme is concerned, assembly of most instrument models has started. A major effort has been made to consolidate the engineering-model and flight- model schedules.
Critical Design Reviews are now in progress at unit and instrument level.
On more general matters, discussions are still continuing at Earth Observation Programme Board and Council level in order to reach agreement on the Programme's funding profile for the coming years.
Envisat ground segment
System
During the first
half of the year, the Earth Observation Programme Board put great
pressure on the Envisat/Polar Platform Programme to reduce its
overall cost-to-completion, whilst still maintaining the
programme objectives and securing the development plan. The
mission objectives have been preserved throughout this cost-
reduction exercise, with all instruments and instrument
performances being maintained and the ground-segment concept
being reconfirmed.
Ground segment
The development effort for the
Flight-Operation Segment is proceeding nominally, with the
Critical Design Review planned for October.
The Payload Data Segment development, led by Thomson-CSF (F), has entered the Critical Design Review stage, as planned, in June. All activities have been kicked-off, except the User Earth Terminal procurement for reception of payload data via Artemis, which planned to start in September, and the data processors, where only the ASAR unit's development is in process.
For all the other instrument processors, definition of the user products and corresponding processing algorithms is being supported by expert laboratories, institutes and industry. These documentation and prototyping activities are already well- advanced for several instruments, allowing the corresponding PDS developments to be started in the near future.
International Space Station Programme (ISS)
International relations
An ISS Incremental Design
Review was held in Houston in March. Several outstanding issues
were settled, particularly with respect to the ESA-provided
early-delivery items to Russia (Data Management System and the
European Robotic Arm). The updating of the ISS Assembly Sequence
to take into account the change of COF launch vehicle from
Ariane-5 to Space Shuttle, together with the delayed launch date
requested by ESA, was carried out at a subsequent review in May.
A series of Technical Interchange Meetings have been held with NASA, during which good progress was made with respect to the resolution of potential problems related to in-orbit installation of payload racks, Shuttle coupled loads analyses, and other technical interfaces.
An extensive Technical Interchange Meeting on the ATV/Russian Segment interfaces took place in Moscow. Agreement was reached on the ATV/ISS Interface Requirements Document, which was approved by ESA and RSC Energia, and the first draft of the corresponding ATV/ISS Interface Control Document was prepared by industry.
A Space Station Control Board Directive baselining the ATV re- boost role in the Concept of Operations and Utilisation (COU), Volume 1, has been issued, this being the first formal step in introducing the ATV into the ISS baseline documentation.
A meeting was held with NASA/GSFC at the end of May to discuss support to the CTV from the US Tracking and Data Relay Satellite System.
Columbus Orbital Facility (COF) Space Segment
The
definition and transfer of system tasks from German industry to
Italy has been successfully completed, and the final contract
price has been negotiated to reflect this transfer, together with
other minor changes. All remaining open technical, programmatic
and contractual points with respect to the COF contract baseline
were satisfactorily resolved during the first half of March, and
the contract was signed with the prime contractor on 28 March.
Final qualification and delivery of the COF developed Mission Database software to NASA was successfully completed, and it has since been used operationally in the ISS Mission Build Facility in Houston.
The possible addition of 'hooks and scars' to the COF (fittings to allow attachment of additional features) is under consideration. Inputs from industry are expected in June.
Atmospheric Re-entry Demonstrator (ARD)
The ARD
assembly and qualification neared completion. Some difficulties
caused by the ARD propulsion equipment's late delivery were
overcome by adapting the integration and verification planning
accordingly.
Automated Transfer Vehicle (ATV)
The Phase-B1 final
review took place over the period 6-31 May. Almost all actions
stemming from the first System Requirements Review were closed
out, with only few left to be completed, consisting mainly of
complementary information to be provided by Russian industry and
finalisation of cargo accommodation assessment.
ATV Rendezvous and Predevelopment (ARP)
Integration
testing of the Global Positioning System and functional tests for
the ATV Rendezvous and Prevelopment activities were successfully
completed at ESTEC, with just one software problem still to be
resolved. This problem was addressed with industry during the
progress meeting held in May.
Crew Transport Vehicle (CTV)
The key results of the
CTV Phase-A studies were presented to the Agency by the CTV prime
contractor in May. The CTV Phase-B Procurement Proposal was
approved by the Agency's Industrial Policy Committee in May, and
the CTV Phase-B Invitation-to-Tender was prepared and mailed to
industry accordingly.
X-CRV
There were discussions with NASA earlier in
the year about the possibility of Europe and NASA cooperating in
the development of a Crew Rescue Vehicle, based on a NASA-
originated concept called X-CRV. A three-month study activity
will be completed in July 1996 and the ongoing CRV/CTV study will
take into account the conclusions of this exercise, if
appropriate.
Ground segment
The procurement approach for the
ground segment was presented to the ESA Manned Space Programme
Board in April. A number of changes were proposed to the
Executive's procurement approach, the most significant of which
related to the inclusion of an option based upon a formal
proposal submitted by some European National Centres just prior
to the Programme Board's meeting. As a result, further technical
clarifications were initiated to assess the technical and
financial merits of the different options before submitting a
final proposal for future procedure to the Participating States.
The procurement of a traffic-modelling tool was initiated. This tool is expected to be operational by the end of 1996 to support ISS traffic-model negotiations with NASA and the Russian Space Agency, and to assist in CTV mission definition.
A small short-term study has been started to analyse the various approaches and supporting rationale followed by the ISS partners for implementing their respective ground segments and operations management functions.
Early deliveries
Data Management System for the
Russian Service Module (DMS-R)
Full agreement was
achieved with the prime contractor and Russian industry for the
detailed implementation into the DMS-R baseline of technical
changes initiated by Russian industry in November 1995, including
some revision of deliverables and adaptation of some delivery
dates. Nonetheless, the overall DMS-R development schedule
remains very critical with respect to committed delivery dates.
The delay in the development of the SPARC chipset which is used by the DMS-R programme is giving cause for concern, and exploratory contacts with a US company as a possible backup supplier have been initiated.
The signature of the ESA/RKA Arrangement as the legal framework between the two agencies for the DMS-R implementation was achieved in March.
European Robotic Arm (ERA)
The ERA Phase-C/D
contract was signed on 19 March, and the Preliminary Design
Review (PDR) was initiated one week later with the release of the
documents that formed the basis for the review of the industrial
data package, delivered on 1 April.
The ERA Preliminary Design Review (PDR) team reviews were completed in the first half of May and the PDR Board met on 15 May. The Board concluded that the PDR objectives had not been met, and confirmed that a number of critical actions defined by the review teams had to be successfully completed before the PDR could be formally closed. The main problem related to the maturity of the ERA design, which was judged insufficient to release the next phase of development. This appeared to be caused primarily by the interval between the subsystem PDRs and the ERA PDR, which had been too short to incorporate the results into the system-level design.
Environmental Control and Life-Support System (ECLS) for
the Italian Mini-Pressurised Logistics Module (MPLM)
The
Phase-C/D industrial proposal was received in the first quarter
of 1996 and, following negotiation, the contract for the full
development phase was signed in May.
The Subsystems Requirements Review was completed and all baseline specifications and plans were approved by the Agency, with the exception of the management plan. Several equipment Preliminary Design Reviews were initiated; completion is planned in June.
During negotiation of the MPLM-ECLS/MPLM Interface Control Document, a potential technical problem emerged relating to fire detection and suppression (air leakage). This was subsequently resolved through the ISS Safety Panel endorsement of MPLM proposed design implementation.
Laboratory Support Equipment
MELFI (Minus Eighty
Degree Centigrade Laboratory Freezer of the ISS): Major
components of the Brayton subsystem including the cold box and
the turbomachine were integrated at the end of March. Following
the test-bench final preparation and checkout, the performance
test was started in early May. The test results so far have
confirmed the validity of the technology selected and the choice
of thermodynamic parameters.
MSG: The Microgravity Science Glovebox (MSG) project has completed its Phase-B and development-model activities. The Phase-B Final Study Review took place at the end of April; the full design and its analytical assessment was presented together with the results of the development-model testing. The Phase-C/D proposal was received at the end of May and preparations are underway for this phase's initiation.
Hexapod: The Phase-B Design Definition Review (DDR) presentation took place on 8/9 May. The follow-on activities will be completed by June 1996. The Phase-B Final Review is scheduled for December.
Utilisation
At the level of coordination of
payloads to be provided by ESA user programmes and by agencies
funded through national programmes, the terms of reference are
being drafted for a European Utilisation Board (EUB) to be set
up by the Manned Space Programme Board. The EUB's main tasks will
be to recommend guidelines and priorities on the European use of
the ISS and to provide the PB-MS with a five-year European
Partner Utilisation Plan (PUP) for decision. The US has already
agreed upon a first version of the US PUP. The various Partner
Plans will be merged at multilateral level to form a final
Consolidated Operations and Utilisation Plan (COUP).
Microgravity Programmes
European Microgravity
Research (EMIR I and II)
The EMIR programme has been
authorised in phases: the first phase (EMIR I) covers the period
1995 through 1997/98, and the second phase (EMIR II, still in the
approval cycle) is planned to cover the period 1996 through 2001.
The matter of subscription will be discussed at the 48th meeting
of the Microgravity Programme Board in June 1996.
The Biorack has been flown for the fourth time, carrying 10 biological experiments. It was accommodated in Spacelab on the third Shuttle mission to MIR, from 22 to 31 March. The Diffusion Coefficient Measurement Facility (dedicated to measuring the diffusion coefficient of mercuric-iodide and accommodated in a 'get-away special' cannister) was flown on the STS-77 Shuttle mission.
The Mir Station
Microgravity Facilities for Columbus (MFC)
The
principal elements of the multi-user facility development
programme covering the period 1997 through 2002 are a Materials
Science Laboratory, a Biolab, and a Fluid Science Laboratory. The
necessary funds will become available in 1997. The current Phase-
B studies are financed from the EMIR I programme.
ESA Bulletin Nr. 87.