LISA Pathfinder

Last updated
LISA Pathfinder
LISA Pathfinder (14257775333).jpg
Model of the LISA Pathfinder spacecraft
Mission typeTechnology demonstrator
Operator ESA [1]
COSPAR ID 2015-070A OOjs UI icon edit-ltr-progressive.svg
SATCAT no. 41043 OOjs UI icon edit-ltr-progressive.svg
Mission duration576 days
Spacecraft properties
Manufacturer Airbus Defence and Space
Launch mass1,910 kg (4,210 lb) [1]
BOL mass 480 kg (1,060 lb) [2]
Dry mass810 kg (1,790 lb)
Payload mass125 kg (276 lb)
Dimensions2.9 m × 2.1 m (9.5 ft × 6.9 ft)
Start of mission
Launch date3 December 2015, 04:04:00 UTC [3] [4] [5]
Rocket Vega (VV06)
Launch site Kourou ELV
Contractor Arianespace
End of mission
DisposalDecommissioned
Deactivated30 June 2017
Orbital parameters
Reference system Sun–Earth L1
Regime Lissajous orbit
Periapsis altitude 500,000 km (310,000 mi)
Apoapsis altitude 800,000 km (500,000 mi)
Inclination 60 degrees
Epoch Planned
Transponders
Band X band
Bandwidth7 kbit/s
Instruments
~36.7 cm Laser interferometer
LISA Pathfinder insignia.png
ESA astrophysics insignia for LISA Pathfinder
←  Gaia
BepiColombo  →
 

LISA Pathfinder, formerly Small Missions for Advanced Research in Technology-2 (SMART-2), was an ESA spacecraft that was launched on 3 December 2015 on board Vega flight VV06. [3] [4] [5] The mission tested technologies needed for the Laser Interferometer Space Antenna (LISA), an ESA gravitational wave observatory planned to be launched in 2037. The scientific phase started on 8 March 2016 and lasted almost sixteen months. [6] In April 2016 ESA announced that LISA Pathfinder demonstrated that the LISA mission is feasible.

Contents

The estimated mission cost was €400 million. [7]

Mission

LISA Pathfinder placed two test masses in a nearly perfect gravitational free-fall, and controlled and measured their relative motion with unprecedented accuracy. The laser interferometer measured the relative position and orientation of the masses to an accuracy of less than 0.01 nanometres, [8] a technology estimated to be sensitive enough to detect gravitational waves by the follow-on mission, the Laser Interferometer Space Antenna (LISA).

The interferometer was a model of one arm of the final LISA interferometer, but reduced from millions of kilometers long to 40 cm. The reduction did not change the accuracy of the relative position measurement, nor did it affect the various technical disturbances produced by the spacecraft surrounding the experiment, whose measurement was the main goal of LISA Pathfinder. The sensitivity to gravitational waves, however, is proportional to the arm length, and this is reduced several billion-fold compared to the planned LISA experiment.

LISA Pathfinder was an ESA-led mission. It involved European space companies and research institutes from France, Germany, Italy, The Netherlands, Spain, Switzerland, UK, and the US space agency NASA. [9]

LISA Pathfinder science

LISA Pathfinder was a proof-of-concept mission to prove that the two masses can fly through space, untouched but shielded by the spacecraft, and maintain their relative positions to the precision needed to realise a full gravitational wave observatory planned for launch in 2037. The primary objective was to measure deviations from geodesic motion. Much of the experimentation in gravitational physics requires measuring the relative acceleration between free-falling, geodesic reference test particles. [10]

In LISA Pathfinder, precise inter-test-mass tracking by optical interferometry allowed scientists to assess the relative acceleration of the two test masses, situated about 38 cm apart in a single spacecraft. The science of LISA Pathfinder consisted of measuring and creating an experimentally-anchored physical model for all the spurious effects – including stray forces and optical measurement limits – that limit the ability to create, and measure, the perfect constellation of free-falling test particles that would be ideal for the LISA follow-up mission. [11]

In particular, it verified:

For the follow-up mission, LISA, [12] the test masses will be pairs of 2 kg gold/platinum cubes housed in each of three separate spacecraft 2.5 million kilometers apart. [13]

Spacecraft design

LISA Pathfinder was assembled by Airbus Defence and Space in Stevenage (UK), under contract to the European Space Agency. It carried a European "LISA Technology Package" comprising inertial sensors, interferometer and associated instrumentation as well as two drag-free control systems: a European one using cold gas micro-thrusters (similar to those used on Gaia), and a US-built "Disturbance Reduction System" using the European sensors and an electric propulsion system that uses ionised droplets of a colloid accelerated in an electric field. [14] The colloid thruster (or "electrospray thruster") system was built by Busek and delivered to JPL for integration with the spacecraft. [15]

LISA Pathfinder exploded view LISA Pathfinder exploded view.jpg
LISA Pathfinder exploded view

Instrumentation

The LISA Technology Package (LTP) was integrated by Airbus Defence and Space Germany, but the instruments and components were supplied by contributing institutions across Europe. The noise rejection technical requirements on the interferometer were very stringent, which means that the physical response of the interferometer to changing environmental conditions, such as temperature, must be minimised.

Environmental influences

On the follow-up mission, eLISA, environmental factors will influence the measurements the interferometer takes. These environmental influences include stray electromagnetic fields and temperature gradients, which could be caused by the Sun heating the spacecraft unevenly, or even by warm instrumentation inside the spacecraft itself. Therefore, LISA Pathfinder was designed to find out how such environmental influences change the behaviour of the inertial sensors and the other instruments. LISA Pathfinder flew with an extensive instrument package which can measure temperature and magnetic fields at the test masses and at the optical bench. The spacecraft was even equipped to stimulate the system artificially: it carried heating elements which can warm the spacecraft's structure unevenly, causing the optical bench to distort and enabling scientists to see how the measurements change with varying temperatures. [16]

Spacecraft operations

Mission control for LISA Pathfinder was at ESOC in Darmstadt, Germany with science and technology operations controlled from ESAC in Madrid, Spain. [17]

Lissajous orbit

The spacecraft was first launched by Vega flight VV06 into an elliptical LEO parking orbit. From there it executed a short burn each time perigee was passed, slowly raising the apogee closer to the intended halo orbit around the Earth–Sun L1 point. [1] [18] [19]

Animation of LISA Pathfinder 's trajectory
Animation of LISA Pathfinder trajectory - Polar view.gif
Polar view
Animation of LISA Pathfinder trajectory - Equatorial view.gif
Equatorial view
Animation of LISA Pathfinder trajectory viewed from the Sun.gif
Viewed from the Sun
   Earth ·  LISA Pathfinder

Chronology and results

The final results (red line) far exceeded from the initial requirements. LISA Pathfinder final results.png
The final results (red line) far exceeded from the initial requirements.

The spacecraft reached its operational location in orbit around the Lagrange point L1 on 22 January 2016, where it underwent payload commissioning. [20] The testing started on 1 March 2016. [21] In April 2016 ESA announced that LISA Pathfinder demonstrated that the LISA mission is feasible. [22]

On 7 June 2016, ESA presented the first results of two months' worth of science operation showing that the technology developed for a space-based gravitational wave observatory was exceeding expectations. The two cubes at the heart of the spacecraft are falling freely through space under the influence of gravity alone, unperturbed by other external forces, to a factor of 5 better than requirements for LISA Pathfinder. [23] [24] [25] In February 2017, BBC News reported that the gravity probe had exceeded its performance goals. [26]

LISA Pathfinder was deactivated on 30 June 2017. [27]

On 5 February 2018, ESA published the final results. Precision of measurements could be improved further, beyond current goals for the future LISA mission, due to venting of residue air molecules and better understanding of disturbances. [28]

See also

Related Research Articles

<span class="mw-page-title-main">Spacecraft propulsion</span> Method used to accelerate spacecraft

Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.

<span class="mw-page-title-main">Laser Interferometer Space Antenna</span> European space mission to measure gravitational waves

The Laser Interferometer Space Antenna (LISA) is a proposed space probe to detect and accurately measure gravitational waves—tiny ripples in the fabric of spacetime—from astronomical sources. LISA would be the first dedicated space-based gravitational-wave observatory. It aims to measure gravitational waves directly by using laser interferometry. The LISA concept has a constellation of three spacecraft arranged in an equilateral triangle with sides 2.5 million kilometres long, flying along an Earth-like heliocentric orbit. The distance between the satellites is precisely monitored to detect a passing gravitational wave.

<span class="mw-page-title-main">BepiColombo</span> European–Japanese satellites heading to Mercury

BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The mission comprises two satellites launched together: the Mercury Planetary Orbiter (MPO) and Mio. The mission will perform a comprehensive study of Mercury, including characterization of its magnetic field, magnetosphere, and both interior and surface structure. It was launched on an Ariane 5 rocket on 20 October 2018 at 01:45 UTC, with an arrival at Mercury planned for on 5 December 2025, after a flyby of Earth, two flybys of Venus, and six flybys of Mercury. The mission was approved in November 2009, after years in proposal and planning as part of the European Space Agency's Horizon 2000+ programme; it is the last mission of the programme to be launched.

<span class="mw-page-title-main">GRACE and GRACE-FO</span> Joint American-German space mission to map Earths gravitational field

The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The two satellites were sometimes called Tom and Jerry, a nod to the famous cartoon. The GRACE Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018.

New Millennium Program (NMP) was a NASA project with focus on engineering validation of new technologies for space applications. Funding for the program was eliminated from the FY2009 budget by the 110th United States Congress, effectively leading to its cancellation.

<span class="mw-page-title-main">Max Planck Institute for Gravitational Physics</span>

The Max Planck Institute for Gravitational Physics is a Max Planck Institute whose research is aimed at investigating Einstein's theory of relativity and beyond: Mathematics, quantum gravity, astrophysical relativity, and gravitational-wave astronomy. The institute was founded in 1995 and is located in the Potsdam Science Park in Golm, Potsdam and in Hannover where it closely collaborates with the Leibniz University Hannover. Both the Potsdam and the Hannover parts of the institute are organized in three research departments and host a number of independent research groups.

The Beyond Einstein program is a NASA project designed to explore the limits of General theory of Relativity of Albert Einstein. The project includes two space observatories, and several observational cosmology probes. The program culminates with the Einstein Vision probes, after completion of the Great Observatories program.

<span class="mw-page-title-main">Gravitational-wave observatory</span> Device used to measure gravitational waves

A gravitational-wave detector is any device designed to measure tiny distortions of spacetime called gravitational waves. Since the 1960s, various kinds of gravitational-wave detectors have been built and constantly improved. The present-day generation of laser interferometers has reached the necessary sensitivity to detect gravitational waves from astronomical sources, thus forming the primary tool of gravitational-wave astronomy.

<span class="mw-page-title-main">Gravitational-wave astronomy</span> Branch of astronomy using gravitational waves

Gravitational-wave astronomy is an emerging field of science, concerning the observations of gravitational waves to collect relatively unique data and make inferences about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang.

The Big Bang Observer (BBO) is a proposed successor to the Laser Interferometer Space Antenna (LISA) by the European Space Agency. The primary scientific goal is the observation of gravitational waves from the time shortly after the Big Bang, but it would also be able to detect younger sources of gravitational radiation, like binary inspirals. BBO would likely be sensitive to all LIGO and LISA sources, and others. Its extreme sensitivity would come from the higher-power lasers, and correlation of signals from several different interferometers that would be placed around the Sun.

<i>Euclid</i> (spacecraft) European visible and near-infrared space observatory

Euclid is a wide-angle space telescope with a 600-megapixel camera to record visible light, a near-infrared spectrometer, and photometer, to determine the redshift of detected galaxies. It was developed by the European Space Agency (ESA) and the Euclid Consortium and was launched on 1 July 2023.

The DECi-hertz Interferometer Gravitational wave Observatory is a proposed Japanese, space-based, gravitational wave observatory. The laser interferometric gravitational wave detector is so named because it is designed to be most sensitive in the frequency band between 0.1 and 10 Hz, filling in the gap between the sensitive bands of LIGO and LISA. Its precursor mission, B-DECIGO, is currently planned for launch in the 2030s, with DECIGO launching at some time afterward.

<span class="mw-page-title-main">Jupiter Icy Moons Explorer</span> European Space Agency spacecraft

The Jupiter Icy Moons Explorer is an interplanetary spacecraft that was launched on 14 April 2023 from Guiana Space Centre in the French Guiana by the European Space Agency (ESA) with Airbus Defence and Space as the main contractor. The mission is planned to study Ganymede, Callisto, and Europa, three of Jupiter's Galilean moons. They are thought to have significant bodies of liquid water beneath their icy surfaces which would make them potentially habitable environments.

<span class="mw-page-title-main">Busek</span> American spacecraft propulsion company

Busek Co. Inc. is an American spacecraft propulsion company that builds thrusters, electronics, and various systems for spacecraft.

NASA's Pathfinder Technology Demonstrator (PTD) Project will test the operation of a variety of novel technologies on a type of nanosatellites known as CubeSats, providing significant enhancements to the performance of these versatile spacecraft. Each of the five planned PTD missions consist of a 6-unit (6U) CubeSat with expandable solar arrays.

Cosmic Vision is the third campaign of space science and space exploration missions in the Science Programme of the European Space Agency (ESA). Formulated in 2005 as Cosmic Vision: Space Science for Europe 2015–2025, the campaign succeeded the Horizon 2000 Plus campaign and envisioned a number of missions in the fields of astronomy and solar system exploration beyond 2015. Ten missions across four funding categories are planned to be launched under Cosmic Vision, with the first being CHEOPS in December 2019. A mission to the Galilean moons (JUICE), the first deep space mission with an opportunistic target, and one of the first gravitational-wave space observatories (LISA), are planned for launch as part of the Cosmic Vision campaign.

The Taiji Program in Space, or Taiji, is a proposed Chinese satellite-based gravitational-wave observatory. It is scheduled for launch in 2033 to study ripples in spacetime caused by gravitational waves. The program consists of a triangle of three spacecraft orbiting the Sun linked by laser interferometers.

<span class="mw-page-title-main">Stefano Vitale</span> Italian / Italian physicist

Stefano Vitale is an Italian physicist and a retired professor of experimental physics at the University of Trento. He is known for his scientific contributions in the field of gravitational wave (GW) research and the successful management of international scientific projects.

References

  1. 1 2 3 "LISA Pathfinder: Operations". ESA. 8 January 2010. Retrieved 5 February 2011.
  2. ↑ "LPF (LISA Pathfinder) Mission". ESA eoPortal. Archived from the original on 2015-10-17. Retrieved 2014-03-28.
  3. 1 2 "Launch Schedule". SpaceFlight Now. Archived from the original on 2016-12-24. Retrieved 2015-10-16.
  4. 1 2 "Call for Media: LISA Pathfinder launch". ESA. 23 November 2015.
  5. 1 2 "LISA Pathfinder enroute to gravitational wave demonstration". European Space Agency . Retrieved 3 December 2015.
  6. ↑ "News: Top News - LISA Gravitational Wave Observatory". Archived from the original on 2016-04-19.
  7. ↑ "LISA Pathfinder To Proceed Despite 100% Cost Growth". Space News. 22 June 2011.
  8. ↑ "LISA Pathfinder Ready for Launch from Kourou" (Press release). Airbus Defence and Space. November 30, 2015 – via SpaceRef.[ permanent dead link ]
  9. ↑ "LISA Pathfinder international partners". eLISAscience.org. Archived from the original on 26 September 2015. Retrieved 7 September 2015.
  10. ↑ science objective of LISA Pathfinder Archived 2014-10-21 at the Wayback Machine .
  11. ↑ "LISA Pathfinder Science". eLISAscience.org. Archived from the original on 21 October 2014. Retrieved 9 July 2014.
  12. ↑ "LISA Gravitational Wave Observatory - We will observe gravitational waves in space - New Astronomy - LISA Pathfinder".
  13. ↑ Official design proposal at https://www.elisascience.org/files/publications/LISA_L3_20170120.pdf
  14. ↑ Ziemer, J.K.; and Merkowitz, S.M.: “Microthrust Propulsion of the LISA Mission,” AIAA–2004–3439, 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Fort Lauderdale FL, July 11–14, 2004.
  15. ↑ Rovey, J. "Propulsion and Energy: Electric Propulsion (Year in Review, 2009)" (PDF). Aerospace America, December 2009, p. 44. Archived from the original (PDF) on 2015-12-08. Retrieved 2012-10-26.
  16. ↑ "LISA Pathfinder Technology". eLISAscience.org. Archived from the original on 21 October 2014. Retrieved 9 July 2014.
  17. ↑ "LISA Pathfinder: Fact sheet". ESA . Retrieved 20 April 2009.
  18. ↑ "LISA Pathfinder: Mission home". ESA . Retrieved 5 February 2011.
  19. ↑ "ESA's new vision to study the invisible universe". www.esa.int. Retrieved 26 June 2014.
  20. ↑ "First locks released from LISA Pathfinder's cubes". ESA. ESA Press Release. February 3, 2016. Retrieved 2016-02-12.
  21. ↑ Amos, Jonathan (1 March 2016). "Gravitational waves: Tests begin for future space observatory". BBC News. Retrieved 2016-03-01.
  22. ↑ Gravitational Observatory Advisory Team, ed. (28 March 2016). The ESA–L3 Gravitational Wave Mission - Final Report (PDF). ESA–L3 Final Report. p. 4.
  23. ↑ M. Armano; et al. (2016). "Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results". Physical Review Letters . 116 (23): 231101. Bibcode:2016PhRvL.116w1101A. doi: 10.1103/PhysRevLett.116.231101 . hdl: 2117/102419 . PMID   27341221.
  24. ↑ "LISA Pathfinder exceeds expectations". ESA. 7 June 2016. Retrieved 7 June 2016.
  25. ↑ "LISA Pathfinder exceeds expectations". Benjamin Knispel. elisascience.org. 7 June 2016. Archived from the original on 3 August 2016. Retrieved 7 June 2016.
  26. ↑ "Gravity probe exceeds performance goals". Jonathan Amos, BBC Science Correspondent, Boston. 18 February 2017. Retrieved 20 February 2017.
  27. ↑ "LISA Pathfinder Will Concludee Trailblazing Mission". ESA Science and Technology. ESA. 20 June 2017. Retrieved 17 August 2017.
  28. ↑ "ESA creates quietest place in space". 2018-02-05. Retrieved 2018-02-07.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.