Mascot - OBC QM & FM
This specification establishes the requirements for design, development, manufacturing, handling and testing of the On-Board Computer (OBC) Hardware (HW) for the Mobile Asteroid Surface Scout (MASCOT).
The OBC-HW is here intended as a set of Printed Circuit Boards (PCBs) to be delivered together with the firmware for the interface with the I/O devices and test software sup-porting the verification of the functional, performance and interface requirements. The PCBs will be housed by the common electronic box (E-box), used to accommodate other electronic parts of Mascot. The E-box and other electronic parts are outside the scope of this specification. An OBC EGSE, simulating the E-box functionality to support the OBC testing, is to be delivered together with each OBC-HW model.
The OBC-HW procurement activity is split in two major work-packages:
— Development of the Engineering Model, with the purpose to verify the overall feasibility of the design in the given PCB envelopes and power resources, develop the FPGA VHDL code and select the major EEE parts,
— Development of the Qualification and Flight Models, porting the EM design and completing it for flight, conducting the full qualification and acceptance verification program.
This specification covers both work-packages.
The document is structured in the following chapters:
— Chapter 1 - Introduction,
— This Chapter,
— Chapter 2 – General Description of Mascot and OBC,
— Describes the Mascot lander and its system components; provides a detail de-scription of the OBC, to be used as reference,
— Chapter 3 - Engineering Requirements,
— Contains the functional, design implementation and interface requirements the OBC has to fulfil,
— Chapter 4 – Environmental and EMC Requirements,
— Contains the general and specific environmental and EMC requirements the OBC has to fulfil,
— Chapter 5 – Assembly, Integration, Verification and Test Requirements,
— Addresses the assembly, verification and the specific test requirements to be fulfilled by the OBC at different levels of integration: stand-alone, integrated in the Mascot lander,
— Chapter 6 - Product Assurance Requirements,
— Addresses the PA requirements to be observed during the development process,
— Chapter 7 - Management Requirements.
... Contains the management, scheduling and reporting requirements applicable to the Mascot mission.
— Chapter 8 – Applicable Documents.
General Description of Mascot and OBC.
Mascot.
The general concept of the “Mobile Asteroid Surface Scout” (Mascot) is to provide a small landing system intended to be deployed from a supporting main spacecraft (“main-SC” or “orbiter”) on an asteroid sample return mission. It is specifically designed to be compatible with JAXA’s Hayabusa 2 (HY2) mission design and the environment given by the target asteroid 1999JU3.
Two major mission phases can be defined for Mascot: A cruise phase, attached to the main-SC, lasting about 5 years, and a nominal phase, detached from the main-SC, lasting about 16 hours.
The baseline design for the Mascot lander is made of the following major subsystems:
Payload: The payload consists of a suite of instruments which fit into the payload com-partments. The instruments are: Magnetometer (MAG), Camera (CAM), Radiometer (MARA), Spectrometer (MicrOmega).
Structure & Accommodation: A highly integrated carbon-fibre composite structure with the vertical wall in the middle of the lander as main load bearing element. A com-mon electronics box (E-box) houses all unit electronics and instrument back-end electronics. The lander is connected to HY2 via a Mechanical and Electrical Support Structure (MESS).
Mobility Mechanism: The mobility mechanism fulfils two functions:
(I) Providing the capability to upright and to correct Mascot's attitude after landing in a way that the instruments are in the correct orientation and at-titude for sampling.
(II) Generating a hopping manoeuvre to relocate Mascot to a different land-ing site. In each way the required motions are generated by driving an in-ternal excenter mass to provide the respective momentum.
Thermal Control: The thermal control is based mainly on passive means such as multi-layer insulations (MLI) and applicable colour coatings. Thus it relies also on a day-night-cycle on the asteroids surface to balance the heat load build up. This constraint drives the selection of the operating window for Mascot. One exception to the passive concept is a redundant heater which is installed on Mascot and used for the thermal control of the batteries during cruise, commissioning and prior to the SDL phase.
Power: The power and energy supply is maintained by a primary battery. Its capacity is dimensioned for an operating time of two asteroid days (~16 hours). The unregulated power bus voltage is converted into auxiliary voltages for MASCOT electronics by an in-ternal Power Distribution and Control Unit (PDCU), located in the common E-box. During cruise and commissioning, the power will be supplied by the main-SC via a regulated power line.
Communication: The communication architecture is based on a JAXA provided radiof-requency transponder, common to other landing experiments carried by HY2 SC. The bit rate will be ~37kbps for telemetry (TM) downlink; ~1.74kbps for telecommand (TC) uplink. The RF channel will be used both during the cruise and nominal mission phases. The communication protocol with HY2 SC is based on CCSDS TM/TC packets.
On-Board Computer: The Mascot design foresees a dual-redundant on-board computer. Its functionality comprises the gathering, compression and storage of the scientific payload and the housekeeping data and to run subsystem tasks or applications. A key application is the “Mascot Autonomy Manager” (MAM) which directs and controls the autonomous operations sequence.
Guidance, Navigation & Control: The key task of the GNC subsystem is to robustly detect the touchdown and MASCOT’s attitude on the asteroids surface. The concept is based on proximity sensors which are integrated by a motion and attitude state filter. GNC algorithms are implemented in the OBC.
Main OBC Functions.
The OBC hardware shall support the OBC functions providing:
— processing capability,
— memory storage for program code and data,
— mass memory storage for data,
— discrete input/output interfaces capability toward lander’s equipment and instruments,
— OBC monitoring and automatic OBC Hardware reconfiguration,
— serial data communication with the lander’s equipment and instruments,
— time maintenance.
Deadline
Die Frist für den Eingang der Angebote war 2012-09-18.
Die Ausschreibung wurde veröffentlicht am 2012-08-09.
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Geschichte der Beschaffung
| Datum |
Dokument |
| 2012-08-09
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Auftragsbekanntmachung
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