Bulletin space for europe (2024)

number 153 | February 2013 bulletin→ space for europe

European Space Agency The European Space Agency was formed out of, and took over the rights and The ESA headquarters are in Paris. obligations of, the two earlier European space organisations – the European Space Research Organisation (ESRO) and the European Launcher Development The major establishments of ESA are: Organisation (ELDO). The Member States are Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, the ESTEC, Noordwijk, Netherlands. Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland and the United Kingdom. Canada is a Cooperating State. ESOC, Darmstadt, Germany. In the words of its Convention: the purpose of the Agency shall be to provide for ESRIN, Frascati, Italy. and to promote, for exclusively peaceful purposes, cooperation among European States in space research and technology and their space applications, with a view ESAC, Madrid, Spain. to their being used for scientific purposes and for operational space applications systems: Chairman of the Council: D. Williams (to Dec 2012)→ by elaborating and implementing a long-term European space policy, by recommending space objectives to the Member States, and by concerting the Director General: J.-J. Dordain policies of the Member States with respect to other national and international organisations and institutions;→ by elaborating and implementing activities and programmes in the space field;→ by coordinating the European space programme and national programmes, and by integrating the latter progressively and as completely as possible into the European space programme, in particular as regards the development of applications satellites;→ by elaborating and implementing the industrial policy appropriate to its programme and by recommending a coherent industrial policy to the Member States. The Agency is directed by a Council composed of representatives of the Member States. The Director General is the chief executive of the Agency and its legal representative. ← On cover: Soyuz flight VS03 lifts off from Europe’s Spaceport in French Guiana on 12 October 2012, on its mission to place the second pair of Galileo satellites into orbit

→ contents 10number 153 | February 2013 02 22The ESA Bulletin is an ESACommunications production.Published by:ESA Communication DepartmentESTEC, PO Box 2992200 AG NoordwijkThe NetherlandsTel: +31 71 565 3408Email: contactesa@esa.intEditor 32 43 56Carl WalkerDesigner BOLDLY GOING WHERE NO EUROPEAN HAS GONE BEFOREEmiliana Colucci ESA’s Service Module for OrionOrganisation Philippe Deloo & Carl Walker → 02www.esa.int/credits ‘V’ FOR VEGETATION The mission of Proba-VThe ESA Bulletin is published by theEuropean Space Agency. Individual Sean Blair → 10articles may be reprinted providedthe credit line reads ‘Reprinted fromESA Bulletin’, plus date of issue. GRAND SCIENCEReprinted signed articles must bear Setting the stage for ESA programmes of the futurethe authors’ names. Marc Heppener et al → 22ESA and the ESA logo are trademarks FLYING HOMEof the European Space Agency.Images copyright ESA unless stated IXV and ISV: a way to affordable and routine access to spaceotherwise. Permission to reproduce Giorgio Tumino → 32or distribute material identified ascopyright of a third party must beobtained from the copyright owner 2012 IN PICTURESconcerned. Some of the most memorable moments and inspirational images taken last year → 43Copyright © 2013European Space Agency News in brief → 50ISSN 0376-4265 | e-ISSN 1608-4713 Programmes in progress → 56

NASA’s Orion spacecraft will be using a Service Module built in Europe, based on ESA’s Automated Transfer Vehicle technology2 www.esa.int

→ orion service module → BOLDLY GOING WHERE NO EUROPEAN HAS GONE BEFOREESA’s Service Module for Orion Philippe Deloo Directorate of Human Spaceflight and Operations, ESTEC, Noordwijk, the Netherlands Carl Walker Communications Department, ESTEC, Noordwijk, the NetherlandsESA and NASA plan to send astronauts farther ATV is a versatile showcase of European space capability,into space than ever before, in Orion spacecraft performing many functions during a mission to the ISS.powered by European Automated Transfer Vehicle The space freighter is used to reboost the ISS and can eventechnology. push the Station out of the way of space debris. While docked, ATV becomes an extra module for the astronauts,When it blasts off atop the Space Launch System rocket and at the end of its mission it takes waste materialsin 2017, NASA’s Orion spacecraft will be using a Service away from the Station.Module built in Europe, derived from ESA’s AutomatedTransfer Vehicle (ATV). ATVs have been resupplying the ESA and NASA signed an agreement last December for theInternational Space Station (ISS) since 2008. The fourth in provision of a Service Module for the Orion’s Explorationthe series, ATV Albert Einstein, is being readied for launch Mission-1 in 2017. The agreement maps out a plan for ESA tothis year from Europe’s Spaceport in French Guiana. fulfil its share of operational costs and additional supporting European Space Agency | Bulletin 153 | February 2013 3

human spaceflight & operations services for the ISS by providing the Orion Service Module and necessary elements of its design. The plan was given the go-ahead at ESA’s Ministerial Council last November and allows European industry to capitalise ATV technology while significantly cutting research and production costs for NASA. NASA plans to make a first unmanned test flight in 2017, meaning that ESA will have to deliver the first Service Module in 2016 – a tight schedule but the people behind ATV are used to delivering a model each year. The first Service Module will be delivered as part of ESA’s contract ↑ The first Orion spacecraft in orbit attached to a Delta for International Space Station utilisation, with an IV upper stage during Exploration Flight Test-1 (NASA) option for a second module to be exchanged in kind for other services still to be identified. Sending European astronauts on Orion is, of course, on the wishlist of the European space community. uncrewed lunar flyby, returning to Earth’s atmosphere at 11 km/s – the fastest reentry ever. Provided these missions The flights go well, Exploration Mission-2 will then launch an Orion with a crew of four astronauts into space in 2021. The first Orion flight will be Exploration Flight Test-1 in 2014, in which an uncrewed Orion will launch on a Delta IV heavy Thomas Reiter, ESA’s Director of Human Spaceflight and rocket and fly to an altitude of around 5700 km above Operations, said, “The cooperation with NASA in the Earth’s surface, farther than a manned spacecraft has gone critical path of a human-rated transportation system, in 40 years. For Flight Test-1, the system will not include a which will take astronauts beyond low Earth orbit, Service Module, but only a structural test adapter built by opens a new page in the transatlantic relationship. It’s Lockheed Martin that connects the capsule to the launcher. a strong sign of trust and confidence in our capabilities, The main objective of this mission is to test the Crew and an important contribution to the future of human Module at re-entry speeds representative of returns from exploration.” beyond low-Earth orbit missions. Nico Dettmann, Head of ESA’s ATV Programme The first European Service Module will fly on Exploration Department, said, “ATV has proven itself on three flawless Mission-1, the first flight of the Orion spacecraft on NASA’s missions to the Space Station and this agreement is new Space Launch System (SLS). This mission will be an further confirmation that Europe is building advanced, reliable spacecraft.” Dan Dumbacher, NASA’s Deputy Associate Administrator for Exploration Systems Development, agrees: “It is a testament to the engineering progress made to date that we are ready to begin integrating designs of an ESA-built Service Module with Orion. Space has long been a frontier for international cooperation as we explore. This latest chapter builds on NASA’s excellent relationship with ESA as a partner in the International Space Station, and helps us move forward in our plans to send humans farther into space than we’ve ever been before.” The Orion vehicle ↑ The NASA/ESA Orion Partnership news conference Orion is the name given to the Multi-Purpose Crew in Houston, 16 January 2013 (from left): William Vehicle, a crewed spacecraft that will transport up to four Gerstenmaier, NASA Associate Administrator for astronauts from Earth’s surface to a nearby destination Human Exploration and Operations; Thomas Reiter, or staging point and bring the crew safely back to Earth ESA Director of Human Spaceflight and Operations; at the end of a mission. Orion consists of a Crew Module, Mark Geyer, Orion Program manager; and Bernardo a Crew Module Adapter, a Service Module, a Spacecraft Patti, ESA Manager of ISS Operations (NASA) Adapter, Spacecraft Adapter Jettisoned Fairings and a Launch Abort System. 4 www.esa.int

→ orion service module Spacecraft Adapter Jettisoned Fairings ESA-provided Service Module, with solar panels shown deployed Crew Module Adapter Crew Module Launch Abort System ↑ Components of NASA/ESA Orion spacecraft (NASA/ESA) Crew ModuleThis vehicle will provide all services necessary to supporta crew during all phases of a given mission, from launch The Crew Module is the command, control, communicationsoperations to Earth entry, descent, landing and recovery and navigation centre for all in-space operations. This(for shorter duration (1–21 days) missions or until a crew module supports up to four astronauts and consists of atransfers to another space vehicle). Orion astronauts will closed, environmentally controlled cabin that provides thewear launch, entry and abort (LEA) suits to protect them habitable volume. The cabin is enclosed by the backshellduring these operations. The LEA suit does not provide and heatshield, which protect it during reentry into Earth’sany in-orbit extravehicular activity capability. atmosphere. The Crew Module is supported by the Service Module systems for most mission durations.Launch Abort SystemThe Launch Abort System provides the capability to Launch Abort Systemtransport the Crew Module away from the launch vehiclestack safely in the event of an emergency on the launch Orion Interim Cryogenic Crew Modulepad or during ascent. When combined with the Crew Propulsion StageModule, it is referred to as the launch abort vehicle. ESA-provided Orion Service Module InterstageSLS solid rocket boosters Core stage Main RS-25 engines ↑ Components of Orion and NASA’s Space Launch System (NASA/ESA) European Space Agency | Bulletin 153 | February 2013 5

human spaceflight & operations Pre-launch and post-landing crew access is through the side The Service Module will be 2.7 m long and 4.5 m wide, hatch on the starboard side of the Crew Module. The hatch similar to the present ATV but a quarter of the length. opens outward to the left side for egress, and is sized for Although ATV’s solar panel configuration will remain, ingress and egress by crewmembers wearing a pressurised they will get a significant upgrade. Slightly shorter and suit. During docked operations and in post-landing contingency wider, the new solar panels for the Service Module will use scenarios, crew access is through the docking hatch. Egress aids gallium arsenide technology and supply more electricity, are provided for post-landing emergency egress. up to 11 kW – enough to power the energy needs of a typical household. These newer solar panels offer 30% The Crew Module includes crew accommodation for eating, efficiency converting solar energy, compared to ATV’s sleeping, hygiene and stowage of tools, hardware, supplies current solar panels, which manage around 17%. and cargo. Interfaces for pressure suits, communications, and biomedical data are provided for each astronaut. Interfaces The Service Module houses the Orion Main Engine for power, vehicle displays and controls, vehicle data and and engine thrust vector control, the reaction control communications are also provided. system and auxiliary thrusters, and the fuel, oxidiser and pressurant tanks for the propulsion system. These provide Crew Module Adapter the in-space propulsion capability for orbital transfer, attitude control and high-altitude ascent aborts. This adaptor provides the structural, mechanical, electrical and fluid interface between the Crew Module and the Service The Main Engine is one of the main differences with the Module. It houses communication equipment, sublimators for current ATV design, which does not have such an engine. thermal heat rejection, and power and data control/interface The Orion Main Engine is an increased performance version electronics. of the rocket engine used by the Space Shuttle for its Orbital Manoeuvering System. This engine will supply around 26 kN Service Module of thrust in addition to eight smaller engines (compared to ATV’s four). The smaller engines will supply a total of 490 N, The European ATV-derived Service Module, sitting directly enough to get Orion back to Earth if needed. under the Crew Module, provides four major system functions to Orion. It provides propulsion, power, thermal control, as Another difference is the thermal control system, well as supplying water and a breathable atmosphere for which is based on an active fluid thermal loop the astronauts. It will remain connected to the Crew Module as in the ISS pressurised element, rather than until just before the capsule returns to Earth. heat pipes used on ATV and other satellites. Crew Module Attitude control RCS thrusters Crew Module Adapter Solar panels Orion Main Engine Auxiliary thrusters ↑ The Orion spacecraft Crew and Service Modules 6 www.esa.int

→ orion service module ↑ Launch of Orion on the Space Launch System vehicle from Kennedy Space Center, Florida (NASA)Additionally, thermal radiators surround the propulsion The missionstanks and, like the Crew Module, the Service Module’spassive thermal control design incorporates multi-layer The official name of Orion is ‘Multi-Purpose Crew Vehicle’,insulation blankets, thermal coatings and micrometeoroid/ meaning that the spacecraft can be used to completeorbital debris shielding. different missions. A number of the possible mission descriptions, called Design Reference Missions, have beenThe Service Module may provide additional volume and created to provide the context in which an ESA-providedother resources for selected missions, for example by Service Module and Spacecraft Adapter may be requiredaccommodating science, engineering demonstrations, to operate. Note that these plans are only intended to helpdevelopment test objectives, or deployment of lunar define the Service Module’s spaceflight capabilities; they mayinfrastructure equipment during the cruise and lunar orbit not necessarily represent missions that will actually be flown.phases of lunar missions. This volume provides electricalpower distribution, network access for command and 1) Uncrewed beyond Earth orbit mission (lunar flyby)control interfaces, and structures and mechanisms. This mission uses a single SLS launch with an interim cryogenic propulsion stage and lunar Orion to goSpacecraft AdapterThe Spacecraft Adapter provides the interface to the launchvehicle during launch and ascent. This adapter attachesthe aft end of the Service Module to the launch vehicle andincludes the structural interface, separation mechanismsand umbilical connectors for communication betweenthe launch vehicle and the Orion. When the launchvehicle burns out, the Orion spacecraft separates from theSpacecraft Adaptor.Spacecraft Adapter Jettisoned FairingsThe Service Module is enclosed by three fairing panels,which protect the solar arrays, radiators and thrustersduring launch and ascent. The fairings may be jettisonedduring the ascent phase or following main engine cutoff of ↑ The Orion spacecraft in low Earth orbit (NASA/ESA)the launch vehicle. European Space Agency | Bulletin 153 | February 2013 7

human spaceflight & operations Orion in lunar orbit (NASA/ESA) beyond Earth orbit and test critical mission events as 2) Crewed beyond Earth orbit mission (lunar orbit) well as demonstrate spacecraft performance in relevant An SLS configuration with an interim cryogenic propulsion environments. The initial SLS configuration places an stage will be used to launch a crewed lunar Orion into low uncrewed Orion in low Earth orbit. The interim propulsion Earth orbit. The interim propulsion stage engine fires to raise stage engine fires to raise its low Earth orbit, and again its low Earth orbit, and again for a trans-lunar injection burn. for a trans-lunar injection burn. When approaching a high lunar orbit, the Orion provides the lunar orbit insertion burn to put the spacecraft into an The trans-lunar injection manoeuvre puts the Orion on a elliptical high altitude lunar orbit. free-return trajectory that is targeted for a lunar closest approach altitude of 100–200 km. The Orion performs A high lunar orbit is used because the Orion is performing a lunar flyby and then returns to Earth. The trajectory both the lunar orbit insertion and trans-Earth injection is designed to achieve a high-speed atmospheric entry burns. The Orion’s elliptical lunar orbit will be between to demonstrate the Orion entry, descent and landing 100–200 km at its lowest point and around 1000 km at systems. Orion’s return velocity will be 11 km/s. its highest. The Orion will remain in lunar orbit for several The future? A manned habitat orbiting an asteroid, served by the joint NASA/ESA Orion spacecraft (NASA/ESA)

→ orion service moduledays and then will perform a trans-Earth injection burn tobegin the return to Earth.3) Crewed lunar vicinity/lunar surface missionThis mission could include a ‘Lunar Surface Sortie’, whichlands four crewmembers on the surface of the Moon in theequatorial or polar regions and returns them to Earth.Two launch vehicle stacks are used in this scenario,the first SLS launch puts a Lunar Lander with acryogenic propulsion stage into low Earth orbit,while the second SLS puts the manned Orioninto low Earth orbit.Instead of docking the Orion with the Landeraround Earth (as was done in Apollo), this planuses a dual lunar orbit rendezvous mission designthat performs rendezvous, operations, docking andundocking in low lunar orbit. Just before separationof the Lander, the Orion is configured for uncrewedoperations. In general, this preparation will not consistof any major powerdowns, since the Orion must be fullyoperational and fault-tolerant to ensure readiness forthe initial separation burn from the Lunar Lander, possibleemergency rendezvous or a normal return from the lunarsurface. Things to be powered down include internal crewinterfaces, displays, lighting, etc.). The crew prepares thespacecraft communications systems for remote commandingfrom the Lander or Earth, and stow equipment in preparationfor the later return of the crew and cargo.The crew transfers into the Lunar Lander and descends to theMoon’s surface. The Lunar Lander would provide habitationfor up to seven days duration on the surface. Deep-spaceextravehicular activity suits will be required for surfaceoperations.4) ISS backup capability missionThis mission provides an alternative means of deliveringcrewmembers and cargo to the ISS if other vehicles areunable to perform that function. Currently, this is just ananalysis, awaiting decisions from the ISS partner agencieson whether this backup will be needed. Orion’s design isoptimised for exploration, but since this capability mustbe available if needed, assessments must be performedto determine the cost, schedule, and technical impact ofimplementing crew rotation and cargo delivery to the ISS.Orion should support a crew for at least four active missiondays, plus two more days as contingency. After orbit insertion,the Orion performs rendezvous, proximity operationsand docking with the ISS. Orion will remain at the ISS in aquiescent mode for up to 210 days (which includes 30 days for Main parachutecontingency) and spend one day undocking and returning to test on the OrionEarth. Contingency days are intended to address cases such as Crew Modulea launch delay of the next crew, or delayed departure due to (NASA)landing site conditions. ■ European Space Agency | Bulletin 153 | February 2013 9

technology & earth observation Proba-V on the cleanroom bench at QinetiQ Space, Belgium, for final testing (QinetiQ) 10 www.esa.int

→ proba-v → ‘V’ FOR VEGETATIONThe mission of Proba-V Sean Blair Communications Department, ESTEC, Noordwijk, The NetherlandsESA’s Proba-V minisatellite is now assembled and Within two days all of our planet’s land surface will bebeing readied for space. With a launch this April, imaged. Once cloud cover is accounted for, a completethis miniature Earth observer is designed to chart composite of Earth’s land cover should be available toglobal vegetation every two days. the scientific community, and a significant number of operational data users, every ten days. Not bad for a cubicResting on a cleanroom bench, it appears to be just a metre’s worth of electronics.box of electronics, about the same size as a modestnetwork server or an office fridge. Yet when ESA’s Proba-V With Proba-V, ESA’s small satellite series has finally come ofminisatellite goes into orbit this spring, it will be able age. Over the last decade, ‘Proba’ has become synonymousto build up a continuous daily picture of the state with small high-performance satellites, designed aroundof vegetation across most of planet Earth: complete innovation. Initially, the two previous satellites in thecoverage of high latitudes each day, with 90% of ‘Project for Onboard Autonomy’ series were demonstrationequatorial regions covered within those same 24 hours. missions, overseen by ESA’s Directorate of Technical and European Space Agency | Bulletin 153 | February 2013 11

technology & earth observation ↑ Proba-V’s Vegetation instrument has been specifically designed for global environmental and agricultural monitoring Quality Management, and intended to give promising Highly prized scientific workhorse technologies an early chance to fly in space. The ‘V’ in Proba-V stands for ‘vegetation’, the mission is These satellites were quickly repurposed as operational needed to extend the dataset of the long-established missions when the high-quality data from their pioneering Vegetation instrument flown on the French Spot-4 and experimental payloads were recognised by users. Launched Spot-5 satellites, launched in 1998 and 2002, respectively. in 2001, Proba-1 was used for hyperspectral environmental Spot-5’s Vegetation instrument is still operational today. monitoring and Proba-2, launched in 2009, made solar observations and monitored space weather. Proba-V is Vital uses of Vegetation data include day-by-day tracking different: it will begin as an operational mission as soon of extreme weather effects, alerting authorities to crop as its commissioning is complete, supplying data to an failures, monitoring inland water resources and tracing existing – and eagerly waiting – user community. the steady spread of deserts and deforestation. Proba-V facts and figures Launch date April 2013 Mass 140 kg Orbit Sun-synchronous polar, 820 km altitude, 10:30 a.m. local time at the descending node Instrument New version of Spot Vegetation instrument Guest technology payloads GaN amplifier in communication subsystem; Energetic Particle Telescope; Satram radiation monitor; ADS-B aircraft signal detector; fibre optics photonics experiment Prime contractor Qinetiq Space (BE) Sentinel-5 precursor Will carry a UV/VIS/NIR/SWIR spectrometer payload to avoid a data gap between Envisat and replacement of the MetOp series of Earth observation satellites Payload developer: OIP Space Systems Ground Station Mission control centre in Redu (BE) with a northerly data reception station, and a processing and archiving centre at VITO (BE) Launcher Vega 12 www.esa.int

→ proba-v“Remote sensing has emerged as a key technology forensuring sustainable land use,” explained Tanja VanAchteren of VITO, the Flemish government environmentalresearch centre responsible for the current Vegetationinstrument’s data processing.“This is an instrument that has been specifically designedfor global environmental and agricultural monitoring,with a very wide 2250 km field of view across blue, red,near-infrared and mid-infrared spectral bands. It candistinguish between different land cover types and plantspecies, including crops, revealing their state of health, aswell as detect water bodies and vegetation burn scars.“Its current 1-km spatial resolution is relatively coarsecompared to other satellite sensors but, in exchange,Vegetation provides a detailed daily snapshot of landcover across a continental scale on a near-daily basis.”There are Earth observation satellites that offer muchhigher resolution imagery, but the price paid for thissharpness is a reduced field of view, not unlike tryingto read a map while peering through a drinking straw. ↑ Landcover of Africa as seen by Spot VegetationGeostationary satellites, observing from a fixed pointrelative to their surface, offer a wider view comparableto Vegetation – but only for a third of Earth’s surface, Running out of timeand with their perspective on higher latitudes growingprogressively more distorted. But despite its valued perspective on the living Earth, the original Vegetation design is an instrument running outSo the Vegetation instrument, born two decades ago, of time. Spot-4 ended Vegetation observations last year,belongs to a narrow class of wide-swath multispectral while the Vegetation mission of its twin satellite Spot-5 isimagers, including NASA’s MODIS and the MERIS projected to end by mid-2014. The Spot satellite family hasinstrument that operated aboard ESA’s Envisat satellite now been commercialised by Astrium to concentrate solelyfor a decade from 2002. Co-financed by Belgium, France, on high-resolution imagery from small satellites. No roomItaly, Sweden and the European Union and designed by was available for another Vegetation instrument on thethe French space agency CNES, the wide-eyed Vegetation Spot-6 mission that was launched in September 2012.has ended up as a highly prized scientific workhorse forglobal change studies. This meant that the nearly 15-year Vegetation dataset looked set to end – at least until the instrument’s“Vegetation data products have around 10 000 registered community of users spoke up. Expressing themselvesusers around the globe, and have contributed to through the Vegetation International Users Committeehundreds of scientific papers,” added Tanja Van Achteren. (IUC), they argued that extended data continuity wasTogether with complementary data from the instruments essential to fully exploit the global capacity of such amentioned above, Vegetation is, for example, a leading crucial spaceborne instrument.source of key European and global vegetation dataproducts (such as Leaf Area Index and Normalised Density “The further a dataset can be extended, the moreVegetation Index) provided to environmental researchers valuable it becomes,” argues Tanja Van Achteren.through the Geoland2 project, backed by the EC’s Seventh “Certainly in the case of climate studies you need at leastFramework Programme. 30 years to begin seeing the underlying trends – so the argument for extending Vegetation observations beyondThese products are harnessed in turn for scientific and the life of the Spot-5 platform really speaks for itself.”operational activities that range from climate impactassessments and surface water resource management to The idea took shape among discussions betweenagricultural monitoring (feeding, for example, the MARS scientists, before being developed further. “The conceptBulletin on European Union crop production forecasts) was quickly adopted by the Belgian authorities,” saidand food security estimates. Jean-Paul Malingreau, Chair of the Vegetation IUC. European Space Agency | Bulletin 153 | February 2013 13

technology & earth observation “They saw in this new mission the opportunity to significantly contribute to global science.” The Belgian Federal Science Policy Office, Belspo, began discussions with ESA on creating a Vegetation follow-on. “The single most important requirement was that it would have to be built and flown quickly,” recounted Karim Mellab, ESA’s Project Manager for Proba-V. “Any new instrument has ↑ Proba-V Flight Model enters the test chamber at to be fully cross-calibrated with Spot-5’s already-orbiting Intespace for thermal/vacuum testing Vegetation instrument to ensure the radiometric and geometric quality and compatibility of its data.” “So the mission was targeting a very narrow time window Back then, only a combination of heavy glass lenses could in space terms, with less than three years from start to yield Vegetation’s 101° field of view, and separate glass launch. That in turn led us consider to a small satellite lenses were required for each of its four spectral bands. Its platform – because, generally speaking, the smaller the sensitive shortwave infrared detectors also demanded a mission, the cheaper and faster it can be mounted.” heavy, power-hungry cooling system. The drive to lose mass led designers to swap glass for lighter aluminium mirrors, The idea took shape for a spacecraft built in Belgium, which have the additional advantage of observing across because the Proba minisatellite platform – produced by all spectral bands without the need for duplication. the QinetiQ Space company – was identified as the best available fit for this new instrument. “To meet such a rapid These mirrors are arranged within a compact ‘three-mirror schedule, we reused as much design heritage from Proba-2 anastigmat’ (TMA) design – but need to be curved in just as possible,” explained the company’s Frank Preud’homme. the right ‘aspherical’ shape. Achieving this required a manufacturing technique of nanometre-scale precision, With QinetiQ Space the overall mission prime contractor, known as ‘single-point diamond turning’, by Belgium-based VITO stepped up from its original data processing and specialist AMOS. distribution role to serve as principal investigator for the redesigned instrument while also taking responsibility for At first, it was uncertain whether this could be achieved at all. its user segment, overseeing the image data processing, But in 2009, a prototype TMA telescope, produced through archiving and distribution as well as the inflight calibration ESA’s General Support Technology Programme which helps and validation. QinetiQ Space subcontracted Belgian develop space hardware to flight readiness, proved the concept. company OIP Sensor Systems to build the redesigned Vegetation instrument. To reduce the size of the mirrors needed in Proba-V’s Flight Model, the instrument has been subdivided into Putting the world in a box three telescopes with overlapping views of 34° each – hence the distinctive triple slits seen on the satellite’s Devising a way to fit a view of the whole world into a small Earth-facing side. The three telescopes feed through to a box has been no easy task, but necessity is the mother of single set of detectors. invention. Engineered to fly on a Spot satellite platform the size of a van, the original 130 kg Vegetation instrument was in Belgian company XenICs developed a 2709-pixel-long linear fact much larger and heavier than the whole Proba satellite. array to cover the shortwave infrared channel, composed of three 1024 detectors originally designed for terrestrial To fit inside the available space and mass budget of applications. These arrays were mechanically butted Proba would mean shrinking the design significantly. together, overlapping to ensure full swath coverage. This miniaturisation process meant harnessing all the technological advances that had taken place since the Because these detectors have been built from indium instrument was first designed in the early 1990s. gallium arsenide, they deliver the high sensitivity needed The further a dataset can be extended, the more valuable it becomes. 14 www.esa.int

→ proba-v (SWIR) across a limited swath within its central nadir- looking telescope. To be compatible with its predecessor, Proba-V’s 820 km polar orbit is Sun-synchronised, giving a local 10:30 time on the ground to give optimal illumination conditions for continuity of measurements. “In terms of spectral bands, there will, however, be a very slight shift in the mid-infrared band; this will enable a better distinction of ↑ Elongated detector array developed by XenICs water bodies,” added Frank Preud’homme. The minisatellite will remain ‘always on’ over Earth’s landwhile still at ambient temperature. This is important surfaces, producing large amounts of data to store andbecause the slimmed-down instrument has to make do downlink for such a modest platform. A novel 16-gigabitwithout any active methods of controlling its temperature. flash memory system will give sufficient onboard storage capacity using data compression, downlinking data once“The risk is that temperature-driven mechanical deformation per orbit to a northern latitude ground station – ESA’smight put the telescopes out of optical alignment as the Kiruna site in the Swedish Arctic during the commissioningsatellite passes from sunlight to darkness,” said Davy phase – via a high-bandwidth X-band antenna.Vrancken, QinetiQ Space Project Manager for Proba-V. The raw data will be relayed automatically to VITO, where“So the instrument rests on an optical bench made of the it will be processed on a near realtime basis into one-daysame aluminium as the mirrors themselves, linked in turn and ten-day products (plus, if requested, the raw 100 mto the star trackers used to orient the satellite. All this resolution product). These products will then be sent outaluminium will expand and contract in the same way, keeping via VITO, this distribution being managed by ESRIN, ESA’sthe telescopes aligned even as their temperature changes.” Earth observation centre in Italy.Temperature-driven deformation is kept to a minimum Once its six-month commissioning is complete andanyway, because the instrument and its optical bench the mission performance is qualified, Proba-V willare kept isolated from the rest of the satellite by low- be transferred from ESA’s Directorate of Technicalconducting titanium struts and shrouded in a dozen and Quality Management to the Directorate of Earthsheets of multilayer insulation. Observation. In particular, its results will support Europe’s flagship Global Monitoring for Environment and Security“Even so, we have also created a detailed model of the (GMES) initiative, developing operational environmentalvery slightest temperature effects on the instrument monitoring services to support European policies andthroughout its orbit. This will enable us to compensate improve the quality of life of European and global citizens,for these effects on the instrument’s geometrical accuracy as well as application development projects and researchduring image processing, to provide the very best possible projects in continuation of previous Vegetation-baseddata quality,” commented Frank Preud’homme. scientific projects, along with those employing Envisat MERIS data products.“Both instrument and mission development proceededon an ‘end-to-end’ basis,” said Karim Mellab. “As part Like its Proba predecessors, the satellite will be controlledof this, a System Performance Simulator allowed us to from ESA’s Redu Centre in Belgium’s Ardennes forest.estimate the quality of the data delivered to users as the The satellite is designed to operate as autonomouslyengineering process unfolded. If necessary, we could goback and retrofit the mission design to enhance quality.” ↓ Under test at ESTEC, the Structural/Thermal Model ofSubstantial improvement Proba-V’s Vegetation instrument – specifically designed for global environmental and agricultural monitoringProba-V’s Vegetation instrument offers a substantialimprovement in data characteristics over its twopredecessors: 1 km-resolution data products will stillbe offered, but 300 m resolution imagery will now beavailable as well, along with an additional uncorrectedproduct available at spatial resolutions of 100 m in visibleand near-infrared (VNIR) and 200 m shortwave infrared European Space Agency | Bulletin 153 | February 2013 15

technology & earth observation as possible, so is overseen by a small team. Redu is also a complementary basis to the Sentinels. Such a ‘Proba-Vb’ where Proba-V’s additional ‘techno-demo’ payloads will be is currently the subject of extensive discussions within operated from, testing promising technologies in space. the Proba-V International Users Committee; it also the topic of a VITO study, supported by ESA’s ‘Programme de With a planned 2.5-year lifetime (with the potential to Développement d’Expériences scientifiques’ (PRODEX) double to five years), Proba-V is sometimes regarded as a technology development programme. n ‘gap filler’ mission: ESA’s Sentinel-3 mission, supporting GMES, is planned for launch in April 2014 and will produce Vegetation-compatible data products. But, if Proba-V proves Sean Blair is an EJR-Quartz writer for ESA a success, it might well make the case for a successor, on Vegetation stress is typically indicated by a decrease → Seeing red in near-infrared reflectivity with a corresponding brightening at mid-infrared. The Vegetation instrument observes Earth’s land surfaces in a spectral region extending from visible light The following biophysical parameters are made available to the invisible near- and mid-infrared. This enables by the EC through a series of environmental and climate measurement of what is called the ‘red edge’. The reason monitoring projects, specifically based on Vegetation why plants appear green in visible light is because the instrument data: chlorophyll in each leaf absorbs red light to perform • Normalised Difference Vegetation Index (NDVI) – photosynthesis. But move into the near-infrared, this the difference in reflectivity between visible red strong absorption suddenly shifts to strong reflectivity and near-infrared from the rest of the leaf’s internal structure. Plant matter • Fraction of vegetation cover (FCover) – the therefore reflects back in the near-infrared much stronger fraction of vegetation per unit area observed than other non-organic surfaces. • Leaf Area Index (LAI) – the total area of (one- sided) photosynthetic tissue per unit area The resulting ‘red-edge’ value – the contrast in brightness observed between the visible red and invisible near-infrared – is the • Fraction of photosynthetically active radiation basis for various vegetation indices commonly employed (fAPAR) – the fraction of incoming solar radiation by environmental scientists, as well as being used directly being absorbed by vegetation cover to estimate the chlorophyll content of the vegetated area • Dry Matter Productivity (DMP) – the increase in being observed. dry matter biomass over time • Burnt areas – forest and other vegetation fire Reflectivity at mid-infrared wavelengths is influenced scars by the presence of water and plant material cellulose • Water bodies and seasonality – tracking the and lignin, and so can be used to derive information presence and extent of water bodies, in Africa on vegetation health and stress due to factors, such as only (in combination with NASA’s MODIS drought or soil salinity, as well as biomass estimates. instrument) ↓ The Brahmaputra and Ganges river delta in India and Bangladesh as seen in infrared from space (CNES/VITO) 16 www.esa.int

→ proba-v→ Proba-V’s fellow passengerProba-V will share its flight to orbit with Estonia’s firstsatellite, ESTCube-1, a 1-kg nanosatellite ‘CubeSat’designed, built and operated by the students of severalEstonian universities and led by the University of Tartuwith Tartu Observatory.The mission will demonstrate a mini-prototype of a newtype of solar sail, and is part of ESA’s Plan for CooperatingStates cooperative agreement with Estonia, a one-yearprogramme of activity as a prelude to the country joiningESA as a Member State.An electric solar sail, or ‘e-sail’ bears little resemblanceto the more usual sail concepts, shaped like a web-likenet. But when electricity is applied through thee-sail, the resulting electrostatic forces repel chargedplasmas found in space – including the Sun’s solarwind – to generate momentum. E-sail technology isbeing developed through the EU’s Seventh FrameworkProgramme by a partnership of nine institutes acrossfive countries.“The plasma in low orbit is quite slow moving relativeto Earth, so the idea is to use e-sails as brakes to deorbit ↑ The electric solar sail concept (Antigravite/Szame)satellites, which is what we’re testing with ESTCube-1,”explained Pekka Janhunen, Finnish MeteorologicalInstitute, inventor of the e-sail concept. “It should be avery different story for future satellites beyond Earth’s currently no existing technologies for deorbiting thesemagnetic field, where the fast-flowing solar wind will objects in the 1–3 kg range.give quite a kick, offering a nearly free ride across theSolar System.” Tethers, put to various uses including power generation, have historically had a mixed record in space – about halfESTCube-1 will unfurl a 10-m long single-strand e-sail to have snapped or failed to deploy. The project is borrowingdemonstrate its potential as a compact and economical techniques from the microelectronics industry to makedeorbiting method. It will measure the resulting tethers just 25–50 µm thick – half the diameterforce acting on the e-sail as it comes into of the average human hair – based oncontact with space plasma. parallel subwires interlinked together. So even if all but one subwiresInternational regulations state in the tether get cut, by athat satellites must deorbit within micrometeoroid for example,25 years of their end of life to then the e-sail should continuereduce space debris. Typically to function. A longer, 100 mthis means reserving propellant e-sail tether will be flown onfor this purpose, shortening the a Finnish student CubeSat,working life of the mission. But by Aalto-1, later in the year.gradually slowing a satellite, thehope is to deorbit small satelliteswithin two to three years instead. ← The Estonian ESTCube-1The e-sail is particularly useful nanosatellite (E. Kulu)for nanosatellites, because there are European Space Agency | Bulletin 153 | February 2013 17

technology & earth observation Preud’homme of QinetiQ Space. “We thought, why not fly → Hitching a ride more working items instead of just metal blocks?” The Proba series offers early spaceflight opportunities for First GaN hardware in space new technologies from European companies. So Proba satellites carry as many technology demonstration packages Proba-V’s X-band communication system will include as possible. an extra amplifier based on new gallium nitride (GaN) technology instead of standard gallium arsenide. Already in The two previous Proba missions were the first to fly everyday use in light-emitting diodes, GaN is attracting great subsequently influential innovations, such as the first interest in the world of integrated circuits. lithium-ion battery for space, the first gallium arsenide solar cells, the first APS-based startracker and the first LEON-2 FT ESA has identified GaN as a key enabling technology for microprocessor, ESA’s latest generation of space computer chips. space: its high power capacity makes it the most promising semiconductor since silicon. GaN operates reliably at With its main Vegetation instrument taking up around a much higher voltages and temperatures than silicon or third of its total volume, Proba-V had less room to spare for gallium arsenide, offering a five- to ten-fold increase in ‘techno-demo’ payloads than its predecessors, but the team communications signal strength without requiring active still did their very best to accommodate as many other items cooling systems. As an additional advantage for space as possible. missions, it is also inherently radiation resistant. “We were able to add an extra couple of payloads by The X-band transmitter on Proba-V is produced by Syrlinks taking out the weights used to keep the satellite’s centre of in Germany, with the GaN amplifier coming from TESAT gravity in balance with its centre of geometry,” says Frank in Germany. This amplifier is among the earliest outputs ↓ Gallium nitride (GaN) circuits on silicon carbide wafers: GaN as a key enabling technology for space 18 www.esa.int

→ proba-v with industrial partner SES Astra on a space-based ADS-B service using a constellation of satellites for global coverage – one of a number of such initiatives in the planning stages around the world. Measuring space radiation Space may be a vacuum, but it is far from empty: particles of ↑ Proba-V will be carrying technology demonstration different energies and charges are thrown out from the Sun packages, offering early spaceflight opportunities for or arrive from deep space, or are captured and accelerated new technologies from European companies within radiation belts of Earth’s magnetic field. Proba-V will carry a pair of instruments to survey space radiation levels, the main cause of satellite anomalies and malfunctions, andof an ESA-led European consortium to manufacture high- a potential health risk to astronauts.quality GaN devices for space uses: the ‘GaN ReliabilityEnhancement and Technology Transfer Initiative’ (GREAT2). Developed by QinetiQ Space and the Centre of SpaceThis innovative amplifier also has an adjustable power Radiation in Belgium, the shoebox-sized Energetic Particleoutput, so its use should help to conserve the small satellite’s Telescope (EPT) will record the charge, energy and angle ofpower consumption while also providing extra redundancy. incoming charged particles along a broad range of energies across a wide 50° field-of-view. Unlike simpler radiationGlobal aircraft detection monitors previously flown in space, the EPT can separate out particles from their energies for much more accurateThe German Aerospace Center DLR has developed an sampling of the radiation flux.instrument to detect Automatic Dependent Surveillance –Broadcast (ADS-B) signals from aircraft. The ADS-B system is A second radiation monitor, known as SATRAM (Spacebeing phased in around the world, with all aircraft entering Application of Timepix-based Radiation Monitor) is contributedEuropean airspace to be equipped with it by 2015. by CSRC and the Czech Technical University. These two radiation monitors will be well placed when Proba-V is launched thisThe system involves aircraft broadcasting their position, spring: the Sun’s 11-year cycle of activity is forecast to peak toaltitude, velocity and other measurements on an automatic the next ‘solar maximum’ by the middle of 2013.basis every second or so. Currently air traffic controllers onthe ground rely on radar contacts to gain an overview of Fibre optics under testair traffic. But with ADS-B transmissions, aircraft remaincontinuously visible, not only to controllers, but also to other The Norwegian T&G Elektro and Spanish DAS Photonicssuitably equipped aircraft. ADS-B requires no costly ground companies have contributed to the payload knowninfrastructure to implement – so sparsely-populated countries as H ERMOD (High Density Space Form Connectorsuch as Australia have been enthusiastic early adopters. Demonstration) to test the capacity of a novel multi-line optical fibre and connector design to operate reliably in theThe idea with this payload is to take up an ADS-B system as space environment.is, foregoing any costly equipment upgrades, and investigateif it is technically feasible to receive ADS-B signals in orbit. Light-based fibre optics offer numerous improvements onProba-V will demonstrate how many aircraft can be observed metal wiring for future space missions, including increasedworldwide and which types – different-sized aircraft are bandwidth, reduced mass and decreased sensitivity toassigned ADS-B systems with differing signal strengths. temperature, radiation and electromagnetic interference.Over European airspace and other high-traffic regions, The payload electro-optics generate different digital signalsadjacent ADS-B signals might well overlap, but space-based to pass through four different optical cables made of 12 fibresADS-B holds potential for monitoring sparsely trafficked and then compare the returned message to the initial one,areas not covered by ground-based radar, such as oceans or counting up the number of errors over time.polar regions. Enlarging coverage in this way should boostoverall air traffic capacity as well as safety and security. Already employed in terrestrial sectors including the oil industry, these multi-line optical fibres were already beingThe principle of detecting ADS-B signals from above rather ground-tested for space as part of ESA’s General Supportthan below has been proved by a DLR experiment carried on Technology Programme when the opportunity arose toa high-altitude balloon, but Proba-V will assess the feasibility fly on Proba-V. A crash effort brought the payload to flightof detecting signals from 820 km up in orbit. DLR is working readiness within six months. European Space Agency | Bulletin 153 | February 2013 19

launchers & earth observation → Voyaging on Vega Proba-V will be launched into orbit on the second Vega flight. Vega made its maiden flight on 13 February 2012 and is ESA’s newest rocket, able to carry small and medium-sized satellites, increasing the flexibility and competitiveness of Europe’s launcher family. This spring marks the start of the VERTA (Vega Research and Technology Accompaniment) programme, intended to demonstrate the flexibility and versatility of the Vega launch system. At a planned minimum of two launches per year, the programme will allow the smooth transition of Vega into commercial exploitation. After Proba-V, VERTA flights will launch the ADM-Aeolus wind- mapping mission, the LISA Pathfinder technology demonstrator and the Intermediate Experimental Vehicle reentry test vehicle. Between 2014 and 2016, Vega will launch ESA’s Sentinel-2 and Sentinel-3 missions, as the start of its commercial operations. ESA’s Directorate of Technical and Quality Management, overseeing the Proba-V mission, has collaborated closely on Vega development with ESA’s Directorate of Launchers and Italy’s Avio company. Like any other ESA project, the Vega team had at their service the specialist engineering teams and laboratories of ESA’s technical centre ESTEC in Noordwijk, the Netherlands. This collaboration beat the odds for an inaugural rocket launch, with a perfect first flight, establishing Vega for its long working life to come. • Vega incorporates a wide range of new materials to keep its own mass low: the lighter Vega is, the more payload it can haul into orbit. Its skin is woven from carbon fibre reinforced polymer then baked solid, a material more typically found in the structures of Formula 1 cars. The resulting vehicle is three times lighter than equivalent metal-bodied rockets, but with a strength-to-weight ratio almost five times greater than steel or aluminium. • The nozzles of the new rocket face some of the most demanding performance requirements of all. The P80 first stage, the Zefiro-23 second stage and Zefiro-9 third stage nozzles are all made from carbon-carbon and of carbon-phenolic composite material. These composites have a tendency to ‘ablate’ – or flake away – at very high temperatures, so much so that carbon phenolic is sometimes used as a heat shield for reentering spacecraft: this flaking effect comes in handy as a way of dumping frictional heat. Robust dynamic testing was needed to ensure the nozzles would not behave the same way under stress. • Guided by decades of experience building and flying Ariane ↑ ESA’s first Vega rocket stands ready for launch launchers, its first three solid-fuel stages are derived from Ariane 5’s strap-on boosters. A reignitable liquid-propellant 20 www.esa.int

→ proba-v↑ View inside the Attitude and Vernier Upper Module, a reignitable liquid-propellant fourth stage containing the avionics that serve as the ‘brain’ of the vehicle fourth stage, the Attitude and Vernier Upper Module (AVUM) is as much a spacecraft as it is a launch stage. This stage completes delivery of Vega payloads into orbit, as well as Fairing and payload space hosting the avionics and thrusters used to control the entire stack’s roll throughout its flight. • New electromechanical actuators are used for the thrust control system of the second, third and fourth stages, controlling their direction during flight. This is the first time these actuators are being used on a European launcher – in Attitude and Vernier Upper Module (AVUM) place of the bulkier hydraulic thrust vector control system used on Ariane 5. Each stage has two actuators for moving the rocket nozzle, an electronic control unit called the Integrated Power Distribution Unit and a lithium-ion battery, all linked by a cable harness. Controlling the system is a HBRISC2 processor, Zefiro-9 third stage capable of surviving radiation as it rises spaceward, while maintaining simultaneous control of the pair of actuators. • Keeping a launcher correctly oriented as it rises through the air is like balancing a pen upright on your finger, made more complicated by the fact that it is not a single item but Zefiro-23 second stage four joined stages accelerating at hypersonic speed. Vega’s 100 000 lines of flight software is not particularly large when compared to the latest satellite missions – with a flight computer running on 1990s-era ERC-32 microprocessors – P80 first stage but failure is never an option. Astrium contributed the flight control software for the first Vega flight, this responsibility passing to the Vega prime contractor ELV for future launches. To control all three axes of flight and take into account external influences, such as wind, the software algorithm ↑ Stages of the Vega launcher has been ‘tuned’ through thousands of simulated flights into orbit over a period of years. European Space Agency | Bulletin 153 | February 2013 21

hispac Capturing the ‘overarching’ aspect of HISPAC’s Grand Science Themes: this view from the ISS includes elements spanning the space sciences (the stars of the Milky Way), Earth sciences (Earth’s surface and thin atmosphere) and even how cosmic radiation interacts with Earth’s magnetic field with an auroral glow (NASA/ESA) 22 www.esa.int