SSETO—Small Satellite for Exoplanetary Transit Observation

SSETO is the result of a phase-A study in context of the small satellite program of the University of Stuttgart that demonstrates the capability of a university institute to build a small satellite with a budget of 5 million Euro. The satellite will be capable of observing exoplanets in a Neptune–Earth scale and obtaining data of interstellar dust. Due to a system failure of NASA?s Kepler mission, there is currently (October 2013) a lack of satellites searching for exoplanets. This paper details the design of subsystems and payload, as well as the required test tasks in accordance with the mission profile at a conceptional level. The costs for standard spacecraft testing and integration tasks are included, but not those of launch, ground support, operations and engineer working hours.     

LARES successfully launched in orbit: Satellite and mission description

On February 13th 2012, the LARES satellite of the Italian Space Agency (ASI) was launched into orbit with the qualification flight of the new VEGA launcher of the European Space Agency (ESA). The payload was released very accurately in the nominal orbit. The name LARES means LAser RElativity Satellite and summarises the objective of the mission and some characteristics of the satellite. It is, in fact, a mission designed to test Einstein's General Relativity Theory (specifically ‘frame-dragging' and Lense-Thirring effect). The satellite is passive and covered with optical retroreflectors that send back laser pulses to the emitting ground station. This allows accurate positioning of the satellite, which is important for measuring the very small deviations from Galilei–Newton's laws. In 2008, ASI selected the prime industrial contractor for the LARES system with a heavy involvement of the universities in all phases of the programme, from the design to the construction and testing of the satellite and separation system. The data exploitation phase started immediately after the launch under a new contract between ASI and those universities. Tracking of the satellite is provided by the International Laser Ranging Service. Due to its particular design, LARES is the orbiting object with the highest known mean density in the solar system. In this paper, it is shown that this peculiarity makes it the best proof particle ever manufactured. Design aspects, mission objectives and preliminary data analysis will be also presented.     

Rosetta: The ESA comet rendezvous mission

Rosetta was selected in November 1993 for the ESA Cornerstone 3 mission, to be launched in 2003, dedicated to the exploration of the small bodies of the solar system (asteroids and comets). Following this selection, the Rosetta mission and its spacecraft have been completely reviewed: this paper presents the studies performed the proposed mission and the resulting spacecraft design.

Three mission opportunities have been identified in 2003–2004, allowing rendezvous with a comet. From a single Ariane 5 launch, the transfer to the comet orbit will be supported by planetary gravity assists (two from Earth, one from Venus or Mars); during the transfer sequence, two asteroid fly-bys will occur, allowing first mission science phases. The comet rendezvous will occur 8–9 years after launch; Rosetta will orbit around the comet and the main science mission phase will take place up to the comet perihelion (1–2 years duration).

The spacecraft design is driven (i) by the communication scenario with the Earth and its equipment, (ii) by the autonomy requirements for the long cruise phases which are not supported by the ground stations, (iii) by the solar cells solar array for the electrical power supply and (iv) by the navigation scenario and sensors for cruise, target approach and rendezvous phases. These requirements will be developed and the satellite design will be presented.     

Sumbandilasat—An operational technology demonstrator

Technology advances in sensor, digital technology and a standardised modular satellite bus are enabling a new generation of 80 kg micro-satellites with a better than 6.5 m GSD multi-spectral performance, to be specified, built and deployed with a dedicated launch within 12 months. The result of the standardised modular bus is lower cost, higher reliability and fast deployment. Operational remote sensing with a micro-satellite is thus within reach of individual organisations for dedicated missions. Sumbandilasat (pioneer in the Venda language) is a second generation satellite technology building on the expertise obtained in the Sunsat small satellite programme. The components used to build Sumbandilasat are the result of a technology development program of more than 3 years. Sumbandilasat is an operational technology demonstrator with more than 90% newly developed or improved subsystems and a compact refractive imager as a precursor to the MSMISat satellite with the same multi-spectral band set. The scalable, standardised modular satellite bus architecture enables satellites with a mass of 80–450 kg to be adapted to the specific mission requirements with minimum new engineering effort.     

ERDSAT,a satellite concept for Earth observations with combined optical and microwave payload

The concept of a European remote sensing satellite (ERDSAT) launched by ARIANE is characterized by a model payload, consisting of a synthetic aperture radar (SAR) and an optical multispectral scanner with 9 channels, for land applications or coastal zone missions. The mission goal of ERDSAT is based on European user requrements where a strong need for optical and microwave sensor operation on board the same satellite in a simultaneous or sequential mode is expressed. A data collection system is included. The proposed spacecraft is three-axes-stabilized and has a Sun-synchronous, near polar circular orbit with 750 km altitude. The selected configuration separates payload module and bus module. A thermostable carbon fibre grating structure is the central framework of the satellite. Each major subsystem is housed in a separate compartment and can be integrated and tested individually. First mass estimates resulted in 450 kg for the payload and 880 kg for the bus. The maximum power needed is 1750 W (for 6 min three times a day), which will be provided by a 1330 W solar array and two batteries. A “low cost” model philosophy is defined; the time schedule envisages a program start in late 1980 and a launch possibility end of 1985.     

远程自主接近轨道设计技术

对完成任务的运载火箭末级、失效卫星等空间非合作目标进行空间操作是复杂的,需要地面测控网与主动航天器的密切合作才能完成抵近及相应操作。以火箭末级残骸作为空间非合作目标,给出了远程自主接近的轨道设计方法。通过地面遥控上传的目标轨道参数,主动航天器进行自主异面机动、主动调相等多次点火,完成对非合作目标的远程接近,接近距离在50km之内,2016年6月底远征一号甲上面级的成功飞行验证了该方法和设计结果的有效性。     

Multiobjective optimization applied to structural sizing of low cost university-class microsatellite projects

In recent years, there has been continuing interest in the participation of university research groups in space technology studies by means of their own microsatellites. The involvement in such projects has some inherent challenges, such as limited budget and facilities. Also, due to the fact that the main objective of these projects is for educational purposes, usually there are uncertainties regarding their in orbit mission and scientific payloads at the early phases of the project. On the other hand, there are predetermined limitations for their mass and volume budgets owing to the fact that most of them are launched as an auxiliary payload in which the launch cost is reduced considerably. The satellite structure subsystem is the one which is most affected by the launcher constraints. This can affect different aspects, including dimensions, strength and frequency requirements. In this paper, the main focus is on developing a structural design sizing tool containing not only the primary structures properties as variables but also the system level variables such as payload mass budget and satellite total mass and dimensions. This approach enables the design team to obtain better insight into the design in an extended design envelope. The structural design sizing tool is based on analytical structural design formulas and appropriate assumptions including both static and dynamic models of the satellite. Finally, a Genetic Algorithm (GA) multiobjective optimization is applied to the design space. The result is a Pareto-optimal based on two objectives, minimum satellite total mass and maximum payload mass budget, which gives a useful insight to the design team at the early phases of the design.     

Simulation model for the operation of space freighters

This paper makes the attempt to illustrate the need for a detailed operational analysis of future space transportation systems with the help of computer-based simulation models. The basic approach deemed suitable for such a systems simulation is explained in some detail. A reference program (100,000 Mg payload per year during 25 years) for a reference mission (heavy cargo transport to GEO for SPS construction) has been selected. A base-line launch vehicle (fully reusable ballistic all chemical three stage vehicle) has been defined, which is considered a serious applicant for such a mission. It was found that the take-off mass of this type of vehicle should be as large as practical from the viewpoint of cost-effectiveness. The example chosen has a GLOW of 10,000 Mg and lifts more than 100 Mg to GEO.With consideration of the operational parameters the simulation model evaluates the annual production rates, inventory of stages, utilization of facilities and operational cost, which amount within this frame of reference to about 96 $/kg net payload delivered to GEO in terms of 1980 dollars and contribute the main share to the total transportation cost.     

European small geostationary communications satellites

Hispasat Advanced Generation 1 (HAG1) is the first satellite using the SGEO platform, which is under the development in the ESA Artes-11 program. Since the last presentation in the IAC 2007, a European industrial consortium led by OHB has completed the mission and spacecraft design. The platform Preliminary Design Review has been carried out in May 2008. The customer for the first mission is a commercial operator—Hispasat. The contract was signed in December 2008 and the satellite will be launched in 2012. To give confidence to the customer, SGEO platform will use up to date flight proven technologies. HAG1 carries 20/24 Ku-band and 3/5 Ka-band transponders to provide commercial services. Some innovative payload technologies will also be flown on board of HAG1 to gain in-orbit heritage. SGEO has also been selected as the baseline platform for the ESA Data Relay Satellite (EDRS). Phase-A study has just kicked off in January 2009. The targeted launch date is 2013. Heinrich Hertz will also use the SGEO platform. Heinrich Hertz is funded by the German Space Agency (DLR) and provides flight opportunities for technologies and components developed by the German Space Industry. With the HAG1 contract in hand, and EDRS and Heinrich Hertz in the line, OHB with its partners has the confidence that it will be able to speed up the product development of the SGEO platform for potential customers in the commercial market. This paper will first present the updated platform design and the status of the product development will be followed with the introduction of innovative payload technologies on board the first mission—HAG1 and ended with the mission concepts of EDRS and Heinrich Hertz missions.     

FPGA-based operational concept and payload data processing for the Flying Laptop satellite

Flying Laptop is the first small satellite developed by the Institute of Space Systems at the Universität Stuttgart. It is a test bed for an on-board computer with a reconfigurable, redundant and self-controlling high computational ability based on the field programmable gate arrays (FPGAs). This Technical Note presents the operational concept and the on-board payload data processing of the satellite. The designed operational concept of Flying Laptop enables the achievement of mission goals such as technical demonstration, scientific Earth observation, and the payload data processing methods. All these capabilities expand its scientific usage and enable new possibilities for real-time applications. Its hierarchical architecture of the operational modes of subsystems and modules are developed in a state-machine diagram and tested by means of MathWorks Simulink-/Stateflow Toolbox. Furthermore, the concept of the on-board payload data processing and its implementation and possible applications are described.     

The IRS-P3 remote sensing mission

ISRO has developed the PSLV rocket (Polar Spacecraft Launch Vehicle) for polar orbiting satellites up to 1000 kg and is conducting a series of test missions. One of this is the IRS-P3, an remote sensing satellite with German participation. The payload consists of 3 scientific instruments: The wide field sensor WiFS for vegetation monitoring (ISRO), the imaging spectrometer MOS (DLR/Germany) for coastal zone and ocean studies an the X-ray astronomy payload (ISRO). The paper gives technical details and parameters on the launch vehicle, the satellite, the instruments and scientific goals and data utilization.     

FPGA-based operational concept and payload data processing for the Flying Laptop satellite

Flying Laptop is the first small satellite developed by the Institute of Space Systems at the Universität Stuttgart. It is a test bed for an on-board computer with a reconfigurable, redundant and self-controlling high computational ability based on the field programmable gate arrays (FPGAs). This Technical Note presents the operational concept and the on-board payload data processing of the satellite. The designed operational concept of Flying Laptop enables the achievement of mission goals such as technical demonstration, scientific Earth observation, and the payload data processing methods. All these capabilities expand its scientific usage and enable new possibilities for real-time applications. Its hierarchical architecture of the operational modes of subsystems and modules are developed in a state-machine diagram and tested by means of MathWorks Simulink-/Stateflow Toolbox. Furthermore, the concept of the on-board payload data processing and its implementation and possible applications are described.     

Technical Feature Analysis of the LM-5 Overall Plan

The Long March 5(LM-5) launch vehicle is China's new generation heavy-lift rocket with the largest payload capacity,representing the highest standard of China's current launchers.It took 10 years to develop the LM-5 launch vehicle.On November 3,2016,the LM-5 carrier rocket blasted off from the Wenchang satellite launch center on Hainan Island,achieving a successful maiden flight.During the development of the LM-5 rocket,the engineering team accumulated abundant experience on developing heavy-lift cryogenic rockets and established a thorough research and development system for new generation launch vehicles,which significantly raised the ability for launcher RD.     

多体回收小型返回舱

把有些航天器(如空间站和侦察卫星等)上的物品返回地面,有两种方法可选用:一种是搭载天地往返运输系统返回,另一种是利用航天器上设置的专用返回舱返回。TAURUS和FAST是德国在80年代末设想的两种多体回收小型返回舱。它们预先装在空间站的贮存库中,需要时即可携带待返物品离开空间站、再入大气层并返回地面。文中主要介绍TAURUS返回舱的运行程序及主要构件(有效载荷舱、弹射装置及辅助设施等)。     

Missions to the asteroid anteros and the space of true anomalies

Three opportunities for missions to rendezvous ballistically with the Earth-crossing asteroid Anteros are studied to illustrate the requirements for a trip to a near-Earth minor planet. The rationale, sample payload, spacecraft requirements and trajectory characteristics of these opportunities are typical of a rendezvous mission to an accessible near-Earth object. Round trip ballistic trajectories to return small samples of the asteroid with launch dates between 1985 and 2000 are also presented. Contours of minimum total ΔV drawn in the space of launch and arrival true anomalies, given the designation Prime Rib curves, are introduced as a useful tool for mission design.     

LISA — a study of the ESA cornerstone mission for observing gravitational waves

The primary objective of the Laser Interferometer Space Antenna (LISA) mission is to detect and observe gravitational waves from massive black holes and galactic binaries in the frequency range 10⁻⁴ to 10⁻¹ Hz. This low-frequency range is inaccessible to ground-based interferometers because of the unshieldable background of local gravitational noise and because ground-based interferometers are limited in length to a few km. LISA is an ESA cornerstone mission and recently had a system study (Ref. 1) carried out by a consortium led by Astrium, which confirmed the basic configuration for the payload with only minor changes, and provided detailed concepts for the spacecraft and mission design. The study confirmed the need for a drag-free technology demonstration mission to develop the inertial sensors for LISA, before embarking on the build of the flight sensors. With a technology demonstration flight in 2005, it would be possible to carry out LISA as a joint ESA-NASA mission with a launch by 2010 subject to the funding programmatics. The baseline for LISA is three disc-like spacecraft each of which consist of a science module which carries the laser interferometer payload (two in each science module) and a propulsion module containing an ion drive and the hydrazine thrusters of the AOCS. The propulsion module is used for the transfer from earth escape trajectory provided by the Delta II launch to the operational orbit. Once there the propulsion module is jettisoned to reduce disturbances on the payload. Detailed analysis of thermal and gravitational disturbances, a model of the drag-free control and of the interferometer operation confirm that the strain sensitivity of the interferometer will be achieved.     

LM-11SL:A Sea-Launched Carrier Rocket for Small Satellites and Its Launch Service

Following the successful maiden flight of the Long March 11(LM-11) launch vehicle from the Jiuquan Satellite Launch Center in September 2015, the first sea-launched carrier rocket dedicated to provide a launch service for small satellites and their constellations, the Long March 11 Sea Launch(LM-11 SL) has been under development by the China Academy of Launch Vehicle Technology(CALT) and the China Great Wall Industry Corporation(CGWIC). It is planned to commence launch service in 2018. Based on the LM-11, a land-launched four-staged solid launch vehicle which has entered the market and accomplished launch missions for several small satellites in the past 3 years, the newly adopted sea launch technology enables transport and launch of LM-11 SL from maritime ships, providing flexible launch location selection.After inheriting the mature launch vehicle technologies from previous members of the Long March launch vehicle family and adopting a new way of launching from the sea, the LM-11 SL is capable of sending payloads into low Earth orbits with all altitudes and inclinations, from 200 km to 1000 km, from equatorial to sun synchronous, within a shortduration launch campaign. The LM-11 SL provides a flexible, reliable and economical launch service for the global small satellite industry.     

Cost effectiveness of Spacelab experiments

Spacelab permits investigation in new seicntific disciplines like material processing, life sciences, chemistry, etc. The large mass and volume capabilities of Spacelab offer better possibilities for some areas of traditional space sciences like infrared astronomy, multi-spectral solar observations and large instruments for astronomical observations.Since free-flyers will require normally a new spacecraft development for each mission, the reusability of space qualified components and experiments will be a significant cost reduction factor over a long period. In the early phase of Spacelab utilisation, however, the scaling factor introduced by Spacelab utilisation, however, the scaling factor introduced by Spacelab results in higher payload development costs than originally appreciated.The costs of Spacelab utilisation are computed and compared with those of conventional free-flying satellites. The mission implementation costs and experiment development costs are shown for both cases. The Spacelab mission implementation costs are subdivided into NASA charges for the Standard Shuttle Mission, NASA charges to fly and operate Spacelab, the European costs of Spacelab payload integration and experiment development costs. In order to evaluate and compare mission implementation costs, the simple parameters are adopted of the cost per kg of experiments and the data collection-transmission capability of Shuttle/Spacelab and ESRO/ESA satellites. The mission implementation costs turn out to be very favourable for Spacelab. The experiment development costs, which are not included in the mission implementation costs, are compared for several free flyers with the corresponding development costs for several experiments of the first Spacelab payload. The comparison shows that the cost per kg of Spacelab experiment development is about five times less than of satellite experiments.     

卫星发射试验风险控制

文章回顾了为保证安全执行发射任务所进行的“风云3号”卫星发射试验风险控制工作:通过分解卫星发射试验流程中的主要事件并结合FMEA和FTA分析结果,辨识并确认了卫星在执行进场发射试验时可能导致任务失败的安全性关键项目,在此基础上从设计、生产、试验、工艺保证、质量控制等方面制定并落实了一系列安全性保障措施,从而确保卫星安全发射。