No one has built a spacecraft or an instrument like this before. Therefore its primary mission is simply to see if it works at all.
“If everything checks out as we hope, this will open the way for a wave of gravitational missions,” says David Southwood, who was the director of science at Esa between 2001-2011, when a large part of the mission’s development took place, “Everyone will start building them but, of course, it’s having the nerve to do it first.”
On that score, LISA-Pathfinder certainly has balls. Two of them. They are the test masses that will respond to the Solar System’s gravitational field. Each weighs 2kg and has been hewn from a €200,000 ingot of gold-platinum alloy. They will essentially float freely inside the spacecraft, moving only as gravity dictates.
“It’s rather similar to Galileo dropping objects from the leaning tower of Pisa,” says Southwood.
When LISA-Pathfinder was approved in 2000, launch was envisaged in 2006. The technology to reach the necessary accuracy, however, has proved so challenging that delays were inevitable.
To watch how the test masses are moving, the spacecraft will bounce a laser beam off them, detecting their motions down to 100,000th of the width of a human hair. It will then shift its own position to keep the test masses centred within it, using thrusters so fine that they could not even blow a piece of paper off a desk on Earth. Yet, in the frictionless environment of space, they can move the whole spacecraft, which will weigh 1900kg at launch.
As well as developing the technology, the engineers faced another unique challenge. “We have had to weigh every single nut and every single bolt to calculate the gravitational field of the spacecraft itself,” says Ian Honstvet, LISA-Pathfinder project manager for Airbus.
That’s because even the minuscule gravity created by a single unaccounted-for cable-tie would be enough to devastate the results. So, the engineers have built a precise computer model of the spacecraft’s components to allow their influence to be subtracted from the results.
Scientists and engineers expect that the primary mission will last between six and twelve months. After that, if there is fuel left, the spacecraft could be sent on a looping, year-long journey around the Earth to make one of the most exciting measurements in modern physics – and provide a much needed reality check on whether most of the matter is in a mysterious unknown form called dark matter.
Our whole view of the universe is built on the assumption that gravity behaves the same in the remotest regions of space as it does on Earth but this has never been tested. The trouble is that the galaxies in the universe all rotate faster than the visible matter contained within them allows.
Most astronomers think that this means swaths of dark matter, hypothetical subatomic particles, must be there to provide the extra gravity to spin the galaxies. But despite decades of efforts and billions spent on the search, no one has managed to convincingly detect a single piece of the stuff. As a result, a small but growing number of scientists are wondering whether the problem lies in our understanding of gravity.
LISA-Pathfinder could test these opposing views by passing through the point between the Earth and our sun where gravity cancels out. If it sees an unexpected gravitational signal here, it would be a landmark in physics; a Nobel prize-winning scientific revolution every bit as huge as those of Newton and Einstein. Our understanding of the whole universe would change direction overnight, and probably we could discount dark matter.
Conversely, if it sees nothing unusual, it will be a tremendous confidence boost that despite all the detection failures, we do need dark matter to explain the motion of galaxies. Either result is profoundly important. So is the technology that the mission will test first.
LISA-Pathfinder is our bridge to the future. In parallel with the gravitational wave observatories being built on Earth, it will open up a whole new way of studying the universe. Be excited.
Dem "Klang" unseres Universums lauschen: Hochempfindliches Kernstück von LISA Pathfinder fertiggestellt
Nach mehr als zehnjähriger intensiver Entwicklungsarbeit ist nun das Kernstück der hochempfindlichen Nutzlast der LISA Pathfinder-Mission bei der Firma Airbus Defence & Space in Friedrichshafen fertiggestellt worden - das LTP Core Assembly. LISA Pathfinder wird vom Deutschen Zentrum für Luft- und Raumfahrt (DLR) im Wissenschaftsprogramm der Europäischen Weltraumorganisation ESA unterstützt. Die Mission soll nach ihrem Start voraussichtlich im Oktober diesen Jahres im Weltraum wichtige Technologien erproben, deren Funktions- und Leistungsfähigkeit am Erdboden nicht oder nur eingeschränkt getestet werden können. Damit ebnet die Mission den Weg für das Gravitationswellen-Observatorium eLISA (evolved Laser Interferometer Space Antenna), das nach seinem für 2034 geplanten Start den energiereichsten und heftigsten astrophysikalischen Ereignissen unseres Universums auf der Spur sein wird.
Dem "Klang" unseres Universums auf der Spur
Fällt ein Stein ins Wasser, so breiten sich von seinem Aufschlagspunkt Schwingungen in Form von Wellen über die Wasseroberfläche aus. Ähnlich wie der Stein auf dem Wasser erzeugen auch große Massen, die sich sehr schnell und ungleichförmig beschleunigt im Weltall bewegen, Wellen. Sie breiten sich im Raum aus und sollten sich als winzige Längenänderungen der Raum-Zeit bemerkbar machen. Diese Gravitationswellen - vom deutschen Physiker Albert Einstein bereits 1916 auf der Grundlage seiner allgemeinen Relativitätstheorie vorausgesagt - lassen uns den "Klang" des Universums "hören" und öffnen so ein neues und unmittelbares Beobachtungsfenster für exotische Himmelsobjekte.
Dazu zählen zum Beispiel Supernovae, enge Doppelsternsysteme bestehend aus Weißen Zwergen, Kollisionen von Neutronensternen und Pulsaren und Zusammenstöße von Schwarzen Löchern mit einigen Sonnenmassen bis hin zu den zentralen Objekten in Galaxienkernen mit der milliardenfachen Masse der Sonne. Gravitationswellensignale aus der Zeit unmittelbar nach dem Urknall können uns mehr über die Entstehung unseres Universums verraten. Wegen der äußerst geringen Wirkung von Gravitationswellen zweifelte Einstein allerdings daran, dass sie jemals nachweisbar wären. Bisher ist es auch nicht gelungen, sie direkt zu messen. Heute - nahezu 100 Jahre nach Einsteins Vorhersage - stehen wir jedoch kurz davor, ihre "extrem leisen" Schwingungen "hörbar" zu machen. Ein Nachweis wird in den nächsten Jahren zunächst vom Erdboden, später aber auch mit eLISA aus dem All erwartet.
LISA Pathfinder ebnet den Weg für eLISA
Das Weltraumobservatorium eLISA wird aus drei Raumsonden bestehen. Sie werden ein gleichseitiges Dreieck mit ungefähr zwei Millionen Kilometern Seitenlänge aufspannen. Das gesamte Dreieck rotiert und wird der Erde auf ihrer Bahn in zehn bis 25 Millionen Kilometern Abstand in einem sogenannten Driftorbit folgen. Die einzelnen Sonden werden durch Laserstrahlen miteinander verbunden - Präzisionsarbeit auf höchstem Niveau. Durchläuft eine Gravitationswelle die Anordnung der Sonden, kann das Observatorium ihre Schwingungen im Frequenzbereich zwischen 0,1 MilliHertz bis 0,1 Hertz "hören". Da die Mission äußerst komplex ist und Komponenten eingesetzt werden, die am Erdboden nicht angemessen getestet werden können, muss die notwendige Technologie zunächst im Weltraum erprobt werden.
Diese Aufgabe wird LISA Pathfinder übernehmen. Die Bestandteile der wissenschaftlichen Nutzlast - des sogenannten LISA Technology Package (LTP) - wurden von mehreren europäischen Ländern entwickelt und von Airbus Defence & Space in Friedrichshafen zur Gesamtnutzlast zusammengesetzt. Das DLR hat im Rahmen des ESA-Wissenschaftsprogramms die Entwicklung der Nutzlast maßgeblich unterstützt. Der deutsche Beitrag wurde dabei wesentlich durch eine Zuwendung des DLR Raumfahrtmanagements an das Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut) in Hannover gefördert.
Nachdem bereits die Steuerelektronik des LTP in die LISA-Pathfinder-Sonde eingebaut und getestet worden ist, folgt nun als letzte und wichtigste Einheit der Nutzlast das sogenannte LTP Core Assembly. Deren Integration ist inzwischen abgeschlossen und die Einheit zur Montage in die Sonde und zu letzten Tests von Friedrichshafen an die Firma IABG in München ausgeliefert worden. Dort wurde inzwischen auch dessen Einbau in die Sonde erfolgreich beendet.
In den zwei separaten Vakuumtanks des LTP sollen während des Betriebs der Mission jeweils eine würfelförmige Testmasse von zwei Kilogramm nahezu frei von allen inneren und äußeren Störkräften schweben und so eine kräftefreie Bewegung im Raum demonstrieren. Eine spezielle Gold-Platin-Legierung sorgt dafür, dass auf die Massen keine magnetischen Kräfte wirken. Eine berührungslose Entladung mit Hilfe von UV-Strahlung verhindert eine elektrostatische Aufladung. Eine besondere Herausforderung ist dabei der sogenannte Caging-and-Venting-Mechanismus, der die Testmassen während der heftigen Vibrationen beim Start schützt, sie höchst kontrolliert freigibt und sie gegebenenfalls auch wieder einfängt. Mittels Laserinterferometrie werden die Positionen und die Ausrichtung der beiden Testmassen relativ zum Satelliten und zueinander mit einer sehr hohen Genauigkeit von etwa einem hundertmillionstel Millimeter gemessen. Darüber hinaus werden die Positionen über weitere Sensoren mit geringerer Genauigkeit erfasst. Die Messdaten sollen dann mit Hilfe eines "Drag-Free Attitude Control System (DFACS)" die Sonde so steuern, dass sie stets auf die Testmassen zentriert bleibt. Die Lage des Satelliten regeln Kaltgas Mikro-Newton-Triebwerke, die für die Astronomie-Mission Gaia entwickelt wurden und den Antriebschub extrem fein und gleichmäßig dosieren können.
Der Start der Mission ist nun für Oktober 2015 geplant. Diesem wird sich ein einjähriger Betrieb auf einer Bahn um den Lagrangepunkt L2, etwa 1,5 Millionen Kilometer in Gegenrichtung zur Sonne von der Erde entfernt, anschließen. Die nach Joseph-Louis Lagrange benannten Punkte sind Orte, in denen zwischen drei Himmelskörpern ein gravitativer Gleichgewichtszustand eintritt, so dass eine Raumsonde an diesen Stellen im Idealfall kräftefrei "verharren" kann.
Airbus Defence and Space has now delivered the LISA Technology Package for the next ESA scientific mission.
Complicated inner workings for a complicated proof: with the LISA Technology Package (LTP), Airbus Defence and Space has now delivered the heart of the LISA Pathfinder scientific space probe. LISA Pathfinder will enable the test of advanced technology with which the gravitational waves described by Einstein can be observed from space. Gravitational radiation will allow astronomers to study our universe in a new way and future telescope systems will be able to observe exotic sources, such as colliding super-massive black holes or neutron stars, as never before.
The LTP has been installed into the satellite also built by Airbus Defence and Space. Both the LTP and the satellite itself must now prove their operational suitability in a comprehensive series of tests at IABG in Ottobrunn, near Munich.
LISA Pathfinder is paving the way for a future large space observatory that ultimately will directly observe and precisely measure gravitational waves. These minute distortions in space-time require very sensitive and highly precise measuring technology, the performance of which can only be tested in a space environment.
The LTP, which weighs around 150 kilograms, consists of a laser interferometer measuring changes in the distance between two precision-engineered gold/platinum test masses, each weighing 1.96 kilograms. Once in orbit, the two test masses will be released from a locking mechanism and then held in position with a weak electrostatic field that can be very precisely controlled. The laser interferometer and electrostatic sensors track the motion of the test masses inside the spacecraft, ensuring that the test masses remain undisturbed. The interferometer can measure the relative position and orientation of the test masses – which are around 40 centimetres from each other – with a high degree of precision (< 0.01 nanometres, which is less than one millionth of the width of a human hair).
The launch of the LISA Pathfinder is scheduled for autumn 2015. Once in orbit, a dedicated propulsion module will take LISA Pathfinder to around 1.5 million kilometres towards the Sun, away from any interference from the Earth.
Airbus Defence and Space in the UK was chosen by the European Space Agency (ESA) to build the LISA Pathfinder and is responsible for delivering the integrated turnkey satellite. Airbus Defence and Space in Germany has been commissioned by the ESA and the German Aerospace Center as the systems leader for the LTP, which was developed with contributions from European research institutes.
Quelle: Airbus Defence and Space
LISA im Test-Modus für Vega Flight VV06
LISA Pathfinder continues to make steady progress in preparation for launch later this year. The most recent tests have focussed on preparing for launch on a Vega rocket.
LISA Pathfinder will be launched from Europe's spaceport in French Guiana on Vega flight VV06 later this year. For launch, the spacecraft will be secured to the Vega launcher by a launch vehicle adapter (LVA).
At the IABG test centre in Ottobrunn, Germany, tests have been carried out with the LISA Pathfinder launch composite – the science and propulsion modules – and the LVA to verify the mechanical and electrical interface between the spacecraft and the launcher.
The launch composite, measuring 3 m in height and 2 m in diameter, is mounted on the LVA with a clamp band interface. The clamp band is a metallic belt that holds two metal rings, one on the LISA Pathfinder launch composite and one on the LVA. The LVA in turn will be bolted on top of the launcher upper stage, called the AVUM – Attitude and Vernier Upper Module.
After launch, when the AVUM together with the LVA and the spacecraft reach the required low Earth orbit, with an apogee of about 1540 km, the spacecraft will be separated from the LVA. This is achieved by firing pyrotechnic devices to release the clamp band and compressed springs which provide a positive separation force.
The launch composite will then use the propulsion module to perform a series of manoeuvres to raise the orbit apogee. Just prior to entry in the operational orbit, a 500 000 km × 800 000 km Lissajous orbit around L1, the propulsion module will be separated from the science module, by firing the pyrotechnic devices of the clamp band which mated the two modules together since launch. This separation is to reduce the disturbance effect of the propulsion module and its residual propellant, enabling drag-free operation of the science module.
With the successful LVA tests completed, the LISA Pathfinder team at IABG prepared for the next Vega-related test. For this, they verified that the LISA Pathfinder launch composite can withstand the intense noise generated by the launcher rocket engines in the first few seconds after ignition. The tests were carried out in the IABG Acoustic Noise Test Facility, in early July 2015.
The acoustic noise tests were the last in a series of environmental tests that ensure the spacecraft can cope with the different conditions it will experience from launch to operation in space. The LISA Pathfinder team at IABG are now preparing for the final activities prior to shipping to the launch site.
ABOUT LISA PATHFINDER
LISA Pathfinder is a European Space Agency mission to test the technology required to detect gravitational waves in the range of 0.1mHz to 1Hz. The mission will demonstrate critical technologies for future gravitational wave observatories, in a space environment. These technologies include: inertial sensing, drag-free attitude control, and interferometry with free-falling mirrors.
An industrial team led by the prime contractor, Airbus Defence and Space - Stevenage, is building LISA Pathfinder. Airbus Defence and Space – Friedrichshafen is the payload architect for the LISA Technology Package (LTP).
Vega Flight VV06
Elements have arrived in French Guiana for the next Vega launcher, which is scheduled for a November mission from the Spaceport to deploy Europe’s LISA Pathfinder – a pioneering scientific spacecraft that will set the stage for observing the Universe in a completely new way.
The Zefiro 23 and Zefiro 9 stages for Arianespace’s lightweight launcher were delivered to French Guiana this month aboard the MN Toucan, one of two ships regularly utilized for transporting Arianespace launcher components from Europe to the company’s South American operations base. They were part of the MN Toucan’s cargo that also included components for an Ariane 5 to be used on a September mission with two telecommunications satellites.
Zefiro 23 and Zefiro 9 are the solid propellant second and third stages, respectively, for the four-stage Vega launcher, which is produced by industrial prime contractor ELV – a jointly owned company of Avio and the Italian Space Agency.
LISA Pathfinder: the first detection of gravitational waves in space
Most existing knowledge about the Universe is based upon the observation of electromagnetic waves – such as visible light, infrared, ultraviolet, radio, X-rays and gamma rays. The European Space Agency’s LISA Pathfinder will pave the way for astrophysicists to address some of the most fundamental questions about the Universe and possibly address new ones through a new observation method.
For the first time, LISA Pathfinder will help test and validate the technology in space needed for detecting low-frequency gravitational waves, which are ripples in space-time predicted by Albert Einstein’s theory of general relativity.
While operating in a 500,000 km.-by-800,000 km. halo orbit around the first Sun-Earth Lagrange point (located 1.5 million km. from Earth), the spacecraft will put two test masses in a near-perfect gravitational free-fall controlled by electrostatic fields. LISA Pathfinder’s inertial sensors, a laser metrology system, a drag-free control system and an ultra-precise micro-propulsion system will be used to control and measure the masses’ motion with unprecedented accuracy.
Scientists predict that gravitational waves should still be “echoing” from the Universe’s formation, and the detection of these waves by LISA Pathfinder would be the most fundamental discovery of its mission. The Airbus Defence and Space-built spacecraft also will measure gravitational waves generated by objects such as collapsing binary star systems and massive black holes.
Sustaining the pace of Arianespace’s operations in 2015
The mission to loft LISA Pathfinder is designated Flight VV06 in Arianespace’s launcher family numbering system, and will be the sixth Vega launch from the Spaceport since its introduction, as well as the lightweight vehicle’s third this year. It follows June’s Flight VV05 to deploy Sentinel-2A and the February suborbital mission with the Intermediate eXperimental Vehicle (IXV) spaceplane on Flight VV04.
Activity for Vega’s late November mission is part of ongoing launcher and payload preparations to support four upcoming Arianespace launch campaigns in French Guiana, along with: Ariane 5 Flight VA225 on August 20; September 10’s Soyuz Flight VS12; and a September mission with Ariane 5, which is designated Flight VA226.
To date, Arianespace has performed six launches in 2015 from French Guiana, comprising three flights with the heavy-lift Ariane 5, two Vega missions and one medium-lift Soyuz launch.
LISAPathfinder is on the road to Kourou, her shown leaving IABG
Preparing the technology to test gravitational-wave detection in space
Name The ‘LISA’ in the mission's name stands for Laser Interferometer Space Antenna, an earlier concept for a spaceborne observatory for gravitational waves, and now used to describe a class of missions based on the original LISA concept. LISA Pathfinder will test key technology for future LISA-like space missions to study the gravitational Universe.
Description LISA Pathfinder will test the technologies needed for future space mission aiming at improving our knowledge of the universe by detecting gravitational waves, a phenomenon predicted by Einstein’s theory of general relativity in 1915. In doing this, LISA Pathfinder will make key measurements of the fabric of spacetime, which will be a crucial component for future fundamental missions as well.
The mission will fly a European payload, the LISA Technology Package (LTP), developed by the European scientific community using national funding from seven Member States (Italy, France, Germany, Spain, United Kingdom, the Netherlands and Switzerland) and from ESA. An American instrument will be hosted on board, the Disturbance Reduction System (DRS), developed for NASA by the Jet Propulsion Laboratory in Pasadena, California.
Launch The launch is scheduled to take place in late 2015.
Status Airbus Defence & Space Stevenage was prime contractor, and Airbus Defence & Space Friedrichshafen led the consortium for the European payload. After completion of the Mission Preliminary Design Review in February 2006, the mission entered the development phase.
Journey LISA Pathfinder will travel from Earth to one of the ‘Lagrangian points’. In these five special places the balance between the gravitational pull from the Sun and Earth allows an object to be stationary in the Sun–Earth system. A spacecraft near one of these points can stay there for long periods of time without the need for major manoeuvres.
LISA Pathfinder will orbit the L1 point, located some 1.5 million kilometres from Earth in the direction of the Sun. The operational phase will last six months but could be extended up to one year.
Notes LISA Pathfinder will use extremely sophisticated technologies in gravitational sensors, electric propulsion, and laser ranging. The purpose of the mission is to validate the technologies required to detect extremely small movements, a science known as ‘precision metrology’.
LISA Pathfinder will prove the techniques and equipment to detect the relative movement of two solid blocks that are freely floating in space to an accuracy of 10 picometres (1 picometre is equal to one millionth of a millionth of a metre).
The AVUM upper stage arrives in French Guiana for Arianespace’s November Vega launch with LISA Pathfinder
The AVUM for Arianespace’s Vega mission with Europe’s LISA Pathfinder scientific spacecraft is unloaded from the MN Toucan roll-on/roll-off sea-going cargo ship after docking at the Port of Pariacabo in French Guiana.
Vega Flight VV06
The liquid upper stage for a November flight utilizing Arianespace’s lightweight Vega vehicle has been delivered to French Guiana, supporting the company’s sustained mission pace in 2015 with its complete launcher family at the Spaceport.
This upper stage – known as the Attitude and Vernier Upper Module (AVUM) – arrived aboard the MN Toucan, a roll-on/roll-off sea-going cargo ship utilized by Arianespace for transporting launcher components from Europe to South America.
The AVUM will help place Europe’s LISA Pathfinder scientific spacecraft on its way to a 500,000 km.-by-800,000 km. halo orbit around the first Sun-Earth Lagrange point (located 1.5 million km. from Earth). Developed by Italy’s Avio, the AVUM is the only liquid propellant system on the four-stage lightweight launcher, and is stacked atop Vega’s solid propellant first, second and third stages.
LISA Pathfinder’s goal is to help test and validate the technology in space needed for detecting low-frequency gravitational waves, which are ripples in space-time predicted by Albert Einstein’s theory of general relativity. Test masses carried by the spacecraft will be put in a near-perfect gravitational free-fall, controlled by electrostatic fields. LISA Pathfinder’s onboard sensors and systems will control and measure the masses’ motion with unprecedented accuracy.
Vega is the smallest vehicle in Arianespace’s launcher family, which is in operation from French Guiana along with the medium-lift Soyuz and heavy-lift Ariane 5. Production of Vega is the responsibility of industrial prime contractor ELV – a company jointly owned by Avio and the Italian Space Agency.
Vega build-up is underway for Arianespace Flight VV06 with LISA Pathfinder
Vega Flight VV06
Assembly of a light-lift Vega has begun for the sixth flight of this smallest vehicle in Arianespace’s launch vehicle family, which is scheduled for November and will send Europe’s LISA Pathfinder on its way for a pioneering space science mission.
The build-up process commenced when Vega’s P80 solid propellant first stage was moved to the Spaceport’s ZLV facility and positioned on the launch pad.
This will be followed by stacking of the launcher’s solid propellant second and third stages, as well as integration of the Attitude and Vernier Upper Module (AVUM) liquid bipropellant upper stage – and then the “topping off” with its passenger: LISA Pathfinder.
Vega has previously been launched five times from French Guiana – deploying a full range of satellite payloads since its introduction at the Spaceport in 2012. Arianespace’s lightweight launcher is produced under the responsibility of industrial prime contractor ELV, a company jointly owned by Avio and the Italian Space Agency.
For the November mission, identified as Flight VV06, Vega will place the European Space Agency’s LISA Pathfinder in a slightly elliptical parking orbit. The spacecraft subsequently will use its own propulsion module to reach the final operational orbit: a 500,000-km.-by-800,000-km. halo orbit around the first Sun-Earth Lagrange point, 1.5 million km. from Earth.
Once operational, LISA Pathfinder will help test and validate the technology in space needed for detecting low-frequency gravitational waves, which are ripples in space-time predicted by Albert Einstein’s theory of general relativity. Test masses carried by the spacecraft will be put in a near-perfect gravitational free-fall, controlled by electrostatic fields. LISA Pathfinder’s onboard sensors and systems will control and measure the masses’ motion with unprecedented accuracy.
LISAPathfinder in French Guiana eingetroffen
The 1.9-tonne probe leaves Stevenage for Stansted Airport and its Antonov flight to French Guiana
Europe's fundamental physics space mission, Lisa Pathfinder, has arrived in French Guiana to prepare for its December Launch.
The probe, whose construction has been led from the UK, will test the technology needed to detect the warping of space-time.
LPF left its Airbus factory in Stevenage on Wednesday to catch an Antonov heavy-lift transporter.
The giant plane touched down in South America early on Thursday.
Pathfinder's next journey will be on top of a Vega rocket, which will hurl it 1.5 million km from Earth to begin its experiments.
That is likely to be on 2 December, depending on the flow of other missions going through the Kourou spaceport.
LPF is the first big European Space Agency venture to be primed industrially in Britain since Giotto, the mission that flew past Halley's comet in 1986.
Pathfinder contains just the single instrument, which is designed to measure and maintain a 38cm separation between two small metal blocks.
These "test masses" will be allowed to free-fall inside the spacecraft, and a laser system will then try to track their behaviour, following deviations down to the level of just a few picometres.
A picometre is a fraction of the width of an atom.
To put it another way, the sensitivity being demanded of the instrument is like measuring the distance from London to New York to well less than the width of a human hair.
And while this precision performance is relatively routine in Earth labs, it is very exacting to try to demonstrate it in space.
But if LPF can prove the technology, it will pave the way for an even bigger mission in the 2030s that will aim to study gravitational waves.
These are incredibly subtle ripples in space-time generated by cataclysmic events such as the merger of monster black holes.
Pathfinder has experienced an extremely tough development path.
The original industrial contract was signed with Airbus Defence and Space (under its old name, Astrium) in 2004, with a launch envisaged for 2008.
However, the immense technical challenge has seen its schedule slip by seven years. Indeed, the problems - to do with probe's delicate thrusters and the caging mechanism to hold the metal blocks - very nearly resulted in the mission being cancelled.
But such is the interest in gravitational waves that Esa member states have pushed forward with the project, and have all but approved the follow-on mission even before Pathfinder has formally demonstrated the detection techniques.
What are gravitational waves?
Gravitational waves are ripples in the fabric of space-time generated by cosmic cataclysms such as the merger of black holes and explosion of huge stars
Extremely sensitive measurement technology is being developed to detect them, using both Earth-based laboratories and satellite systems in orbit
Just like light (electromagnetic radiation), gravitational waves have a spectrum, and it is the lower frequencies that space-borne observations would seek
Targets would include the truly colossal phenomena in the Universe, such as the super-massive black holes that spiral into each other when galaxies merge
Gravitational wave detectors would enable astronomers to open a window on this "dark" activity, potentially revealing physics beyond Einstein
Vega Flight VV06
The LISA Pathfinder demonstrator for space-based observations of gravitational waves is undergoing checkout at the Spaceport, preparing it for a December 2 launch on Arianespace’s sixth flight of the Vega light-lift launcher from French Guiana.
This activity is being performed in the S5C hall of the Spaceport’s S5 payload processing facility, with the work being led by teams from LISA Pathfinder prime contractor Airbus Defence and Space.
LISA Pathfinder is a mission organized by the European Space Agency (ESA). The probe is designed to test critical concepts and technologies related to the detection of gravitational waves – the ripples in space-time predicted by Albert Einstein’s General Theory of Relativity.
LISA Pathfinder will be placed by Vega in an elliptical Earth orbit
After being lofted by Vega on Arianespace Flight VV06, the spacecraft will enter an elliptical Earth orbit, then use its own propulsion module to reach the operational orbit for six months of scientific and technical operations around the first Sun-Earth Lagrange point (L1), located approximately 1.5 million kilometers from Earth.
LISA Pathfinder is unusual in design. Conceived to be the “quietest” spacecraft ever launched, it does not possess a typical payload structure – since the spacecraft as a whole is part of the experiment. At its core are two individual freely-falling test masses: cubes of gold-platinum alloy whose distance apart will be monitored by a complex laser system.
The satellite’s technology package was developed by European companies, research institutes and ESA; while a disturbance reduction system was provided by the U.S. NASA space agency.
Vega’s integration continues for Flight VV06
LISA Pathfinder will have an estimated liftoff mass of 1,910 kg. and will be lofted from French Guiana atop the four-stage Vega – which currently is being integrated at the Spaceport’s ZLV launch facility.
In the latest step of its build-up, Vega’s Zefiro 23 solid propellant second stage was mated this week to the P80 first stage – which is positioned on the launch pad inside a protective mobile gantry.
Vega began operation in 2012 and is designed to carry the growing number of small scientific spacecraft and other lighter-weight payloads under development worldwide. As the smallest member of Arianespace’s launcher family – which also includes the medium-lift Soyuz and heavyweight Ariane 5 – Vega is produced under the responsibility of industrial prime contractor ELV, a company jointly owned by Avio and the Italian Space Agency.
Vega Flight VV06
The sixth Vega to be launched from French Guiana has completed its basic assembly at the Spaceport, readying this light-lift vehicle to receive Europe’s LISA Pathfinder scientific spacecraft for an Arianespace mission in December.
Vega’s build-up was performed on the Spaceport’s ZLV launch pad, with the vehicle protected by a mobile gantry. The initial assembly was accomplished when Vega’s AVUM (Attitude and Vernier Upper Module) upper stage was integrated atop the launcher’s three lower solid-propellant stages. The AVUM uses liquid bi-propellant for primary maneuvering, along with cold gas for attitude control.
With this assembly activity achieved, Vega is now ready to receive its LISA Pathfinder payload for the December 2 launch, which is designated Flight VV06 in Arianespace’s launcher family numbering system. The probe was developed in a European Space Agency (ESA) program and is designed to test critical concepts and technologies related to the detection of gravitational waves – the ripples in space-time predicted by Albert Einstein’s General Theory of Relativity.
Vega to place LISA Pathfinder on its way to the L1 Lagrange point
Built under the responsibility of prime contractor Airbus Defence and Space, LISA Pathfinder is to be placed by Vega in an initial elliptical Earth orbit. The spacecraft’s own propulsion module will be used to reach the operational orbit around the first Sun-Earth Lagrange point (L1) – located approximately 1.5 million kilometers from Earth.
The Vega launch vehicle entered service in February 2012, and its five missions conducted to date from French Guiana have orbited a full range of payloads – from Earth imaging satellites and climate change observation platforms to technology demonstrators and an experimental spaceplane.
Vega is tailored to accommodate scientific, institutional, governmental and commercial satellites, joining Arianespace’s medium-lift Soyuz and heavy-lift Ariane 5 launchers in side-by-side operations from the Spaceport. The development of Vega was performed in a multinationally-financed European Space Agency program, with launcher’s design authority and prime contractor role performed by Italy’s ELV company – a joint venture of Avio and the Italian Space Agency.
LISA Pathfinder is “topped off” for its Arianespace Vega launch to test the General Theory of Relativity
Vega Flight VV06
The LISA Pathfinder scientific space probe to be launched by Arianespace’s next Vega flight has received its propellant load for a mission to study the ripples in space-time predicted by Albert Einstein’s General Theory of Relativity.
LISA Pathfinder is filled with its propellant load in preparation for the spacecraft’s launch on Arianespace Flight VV06.
LISA Pathfinder was “topped off” in the Spaceport’s S5 payload preparation facility, taking it one step closer to a December 2 launch from French Guiana on Arianespace Flight VV06 – the light-lift Vega’s sixth launch since entering service in 2012.
The European Space Agency space probe was built under the responsibility of prime contractor Airbus Defence and Space, and will be placed by Vega in an initial elliptical Earth orbit. The spacecraft’s own propulsion module will be utilized to reach the operational orbit around the first Sun-Earth Lagrange point (L1) – located approximately 1.5 million kilometers from Earth.
To evaluate the concept of low-frequency gravitational wave detection, LISA Pathfinder will put two test masses in a near-perfect gravitational free fall, controlling and measuring their motion with unprecedented accuracy. The test masses will be suspended inside their own vacuum containers, with LISA Pathfinder designed as the quietest spacecraft ever launched – allowing for extremely small distance measurements with the masses to be performed by an onboard interferometer.
Vega is the smallest member of Arianespace’s launcher family, tailored to accommodate scientific, institutional, governmental and commercial satellites. It operates along with the medium-lift Soyuz and heavy-lift Ariane 5 at the Spaceport.
The development of Vega was carried out in a multinationally-financed European Space Agency program, with the launcher’s design authority and prime contractor role performed by Italy’s ELV company – a joint venture of Avio and the Italian Space Agency.
Title Encapsulation begins
Released 17/11/2015 4:22 pm
Copyright ESA–Manuel Pedoussaut, 2015
LISA Pathfinder being encapsulated within the half-shells of the Vega rocket fairing on 16 November 2015, at the Centre Spatial Guyanais in Kourou, French Guiana.
LISA Pathfinder will test the fundamental technologies and instrumentation needed for such an observatory, demonstrating them for the first time in space. LISA Pathfinder is currently scheduled for launch with Arianespace flight VV06 – the sixth launch of Europe's small Vega launcher – on 2 December at 04:15:00 UTC.
Next Arianespace Flight VV06: Vega to orbit LISA Pathfinder for the European Space Agency (ESA)
Kourou, November 25, 2015
For the 11th launch of 2015 from the Guiana Space Center, the Vega light launcher on its overall sixth mission, this time on behalf of ESA, will orbit the LISA Pathfinder technology demonstrator, into an elliptical low earth orbit for a mission to the L1 Lagrange point.
With this seventh launch of the year overall for European Governments, this time focusing on space research and science, Arianespace, once again, reflects the company's assigned mission of ensuring independent access to space for Europe.
The launch will be carried out from the Vega launch complex (SLV) in Kourou, French Guiana.
Targeted orbit: Elliptic low earth orbit for a mission to the L1 Lagrange point (at 1.5 million km from Earth)
Perigee: 207 km
Apogee: 1,540 km
Inclination: 5.96 degrees.
Liftoff is scheduled for Wednesday, December 2, 2015, at exactly:
• 01:15:00 a.m. (local time in French Guiana),
• 11:15:00 p.m. (Washington, DC), on December 1st
• 04:15:00 a.m. (UTC),
• 05:15:00 a.m. (Paris).
The mission, from liftoff to release of the satellite, will last 1 hour, 45 minutes and 33 seconds.
The launcher will carry a total payload of 1,986 kg, including 1,906 kg for the LISA Pathfinder satellite, which will be injected into its targeted orbit.
The Launch Readiness Review (LRR) will take place on Monday, November 30, 2015 in Kourou, to authorize the start of operations for the final countdown.
Developed by ESA, the LISA Pathfinder technology demonstrator will pave the way for future spaceborne gravitational-wave observatories that will ultimately observe and precisely measure gravitational waves, "ripples in the fabric of space-time" predicted by Albert Einstein’s general theory of relativity.
LISA Pathfinder is the first step toward observing Einstein’s gravitational waves from space. Its mission objective is to test the innovative technologies needed to directly detect these distortions.
To watch a live, high-speed transmission of the launch, go to www.arianespace.com on December 2, 2015 (including local commentary in French or English), starting 20 minutes before liftoff. You can also follow the launch live on your iPhone or iPad (the Arianespace.tv app is free).
For further information, download the launch press kit here: www.arianespace.com/news-launch-kits/launch-kit.asp
Arianespace is the world’s leading satellite launch company. Founded in 1980, Arianespace deploys a family of three launchers, Ariane, Soyuz and Vega, to meet the needs of both commercial and government customers, and has performed 270 launches to date. Backed by its 20 shareholders and the European Space Agency, Arianespace is the only company in the world capable of launching all types of payloads into all orbits, from the Guiana Space Center in French Guiana. As of November 25, 2015, Arianespace had carried out 227 Ariane launches, 38 Soyuz launches (12 at the Guiana Space Center and 26 from the Baikonur Cosmodrome, via Starsem) and five Vega launches. Arianespace is headquartered in Evry, near Paris, and has a facility at the Guiana Space Center, plus local offices in Washington D.C., Tokyo and Singapore.
Title Vega VV06 fully assembled in its mobile gantry
Released 20/11/2015 9:22 am
Copyright ESA–Manuel Pedoussaut, 2015
Vega VV06, carrying LISA Pathfinder, is fully assembled in its mobile gantry, in the launcher assembly area, at Europe's Spaceport in Kourou, French Guiana, on 19 November 2015.
LISA Pathfinder will test the fundamental technologies and instrumentation needed for future gravitational-wave observatories in space. LISA Pathfinder is currently scheduled for launch with Arianespace flight VV06 – the sixth launch of Europe's small Vega launcher – on 2 December at 04:15:00 UTC.