Philae

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This article is about the Philae lander. For its spaceflight mission, see Rosetta (spacecraft). For events, see Timeline of Rosetta spacecraft.
Philae
Philae over a comet (crop).jpg
Illustration of Philae approaching the comet
 
Mission type Comet lander
Operator European Space Agency
COSPAR ID PHILAE
Website www.esa.int/rosetta
Mission duration 1–6 weeks (planned)
 
Spacecraft properties
Launch mass 100 kg (220 lb)[1]
Payload mass 21 kg (46 lb)[1]
Dimensions 1 × 1 × 0.8 m (3.3 × 3.3 × 2.6 ft)[1]
Power 32 watts at 3 AU[2]
 
Start of mission
Launch date 2 March 2004, 07:17 (2004-03-02UTC07:17Z) UTC
Rocket Ariane 5G+ V-158
Launch site Kourou ELA-3
Contractor Arianespace
 
67P/Churyumov–Gerasimenko lander
Landing date 12 November 2014
15:35 UTC
Instruments
APX Alpha: Alpha Particle X-ray Spectrometer
ÇIVA: Comet nucleus Infrared and Visible Analyzer
CONSERT COmet Nucleus Sounding Experiment by Radiowave Transmission
COSAC: COmetary SAmpling and Composition
MUPUS: Multi-Purpose Sensors for Surface and Subsurface Science
PTOLEMY: gas chromatograph and medium resolution mass spectrometer
ROLIS: ROsetta Lander Imaging System
ROMAP: ROsetta lander MAgnetometer and Plasma monitor
SD2: Sample and Distribution Device
SESAME: Surface Electric Sounding and Acoustic Monitoring Experiment

Philae (/ˈfaɪli/[3] or /ˈfiːleɪ/)[4] is a robotic European Space Agency lander that accompanied the Rosetta spacecraft[5] until its designated landing on Comet 67P/Churyumov–Gerasimenko (67P), more than ten years after departing Earth.[6][7][8] On 12 November 2014, the lander achieved the first-ever controlled touchdown on a comet nucleus.[9][10] Its instruments are expected to obtain the first images from a comet's surface and make the first in situ analysis to determine its composition.[11] Philae is tracked and operated from the European Space Operations Centre (ESOC) at Darmstadt, Germany.[12]

The lander is named after Philae Island in the Nile, where an obelisk was found and used, along with the Rosetta Stone, to decipher Egyptian hieroglyphics.

Mission

Video report by the German Aerospace Center about Philae '​s landing mission. (10 min, English, in 1080p HD)

Philae '​s mission is to land successfully on the surface of a comet, attach itself, and transmit data from the surface about the comet's composition. Unlike the Deep Impact probe, which by design struck comet Tempel 1's nucleus on 4 July 2005, Philae is not an impactor. Some of the instruments and the lander were used for the first time as autonomous systems during the Mars flyby on 25 February 2009. ÇIVA, the camera system, returned some images while the Rosetta instruments were powered down; ROMAP took measurements of the Martian magnetosphere. Most of the other instruments need contact with the surface for analysis and stayed offline during the flyby. An optimistic estimate of mission length is "four to five months".[13]

Scientific goals

The scientific goals of the mission focus on "elemental, isotopic, molecular and mineralogical composition of the cometary material, the characterization of physical properties of the surface and subsurface material, the large-scale structure and the magnetic and plasma environment of the nucleus."[14]

Landing


Photograph of comet 67P taken by Philae approximately 10 km from the surface on 9 November 2014. This image represents an area 857x857 meters.[15]

Philae remained attached to the Rosetta spacecraft after rendezvousing with comet 67P/Churyumov–Gerasimenko until 12 November 2014. On 15 September 2014, ESA announced Site J, named Agilkia in honour of Agilkia Island by an ESA public contest,[16] on the "head" of the comet as the lander's destination.[17]

A series of four Go/NoGo checks were performed 11–12 November 2014. One of the final tests before detachment from Rosetta showed that the lander's cold-gas thruster was not working correctly, but the "Go" was given anyway, as it could not be repaired.[18][19] Philae detached from Rosetta on 12 November 2014 at 08:35 UTC, landing seven hours later at 15:35.[20][21] A confirmed landing signal was received at 16:03 UTC.[1][22]

In an update from the LCC in ESA's live stream at 16:42 UTC, it was announced that analysis of telemetry indicated that the landing was softer than expected, but that the harpoons had not deployed upon landing, and that the thruster had not fired.[23][24] The harpoons contain 0.3 grams nitrocellulose which were indicated by Copenhagen Suborbitals in 2013 to be unreliable in vacuum, but Reinhard Roll from Max Planck Institute says they have worked out a solution.[25] Subsequent readings indicated that the lander possibly drifted from comet after impact and touched down again. Dr. Stephan Ulamec, Rosetta project manager, stated that "Maybe, today, we didn't just land once, we landed twice!"[26] Further analysis indicated that the lander had bounced twice and landed three times; the first bounce lasted two hours and may have been one km high; the second lasted 7 minutes.[27][28] Philae sits askew on two legs, leaning on a rock as much as a kilometer from the first landing spot.[29][30] ESA published pictures using Getty Images.

Design


Rosetta and Philae

The lander was designed to deploy from the main spacecraft body and descend from an orbit of 22.5 kilometres (14 mi) along a ballistic trajectory.[31] It would touch down on the comet's surface at a velocity of around 1 metre per second (3.6 km/h; 2.2 mph).[32] The legs were designed to dampen the initial impact to avoid bouncing as the comet's escape velocity is only around 0.5 m/s (1.8 km/h; 1.1 mph),[33] and the impact energy would drive ice screws into the surface.[34] Philae would then fire two harpoons into the surface at 70 m/s (250 km/h; 160 mph) to anchor itself.[35][36] A thruster on top of Philae would fire to lessen the bounce upon impact and to reduce the recoil from harpoon firing.[18]

Communications with Earth will use the orbiter spacecraft as a relay station to reduce the electrical power needed. The mission duration on the surface is planned to be at least one week, but an extended mission lasting months is possible.

The main structure of the lander is made from carbon fiber, shaped into a plate maintaining mechanical stability, a platform for the science instruments, and a hexagonal "sandwich" to connect all the parts. The total mass is about 100 kilograms (220 lb). Its "hood" is covered with solar cells for power generation.[7]


Philae landing site Agilkia (Site J)

It was originally planned to rendezvous with the comet 46P/Wirtanen. A failure in a previous Ariane 5 launch vehicle closed the launch window to reach the comet. It necessitated a change in target to the comet 67P/Churyumov–Gerasimenko. The larger mass of comet 67P and the resulting increased impact velocity required that the landing gear of the redesigned lander be strengthened, in order for the spacecraft and its delicate scientific instruments to survive the landing.[citation needed]

Spacecraft component Mass[14]:208
Thermal Control System 3.9 kg (8.6 lb)
Power System 12.2 kg (27 lb)
Active Descent System 4.1 kg (9.0 lb)
Flywheel 2.9 kg (6.4 lb)
Landing Gear 10 kg (22 lb)
Anchoring System 1.4 kg (3.1 lb)
Central Data Management System 2.9 kg (6.4 lb)
Telecommunications System 2.4 kg (5.3 lb)
Common Electronics Box 9.8 kg (22 lb)
Mechanical Support System, Harness, balancing mass 3.6 kg (7.9 lb)
Scientific payload 26.7 kg (59 lb)
Sum 97.9 kg (216 lb)

Power management

Philae power management has been planned for two phases. In the first phase, the lander will operate solely on battery power. In the second phase, "it will run on backup batteries recharged by solar cells".[13]

Instruments


Philae '​s instruments

The science payload of the lander consists of ten instruments massing 26.7 kilograms (59 lb), making up just over one-fourth of the mass of the lander.[14]

APXS
The Alpha Particle X-ray Spectrometer detects alpha particles and X-rays, which provide information on the elemental composition of the comet's surface.[37] The instrument is an improved version of the APXS of the Mars Pathfinder.
COSAC 
The COmetary SAmpling and Composition instrument is a combined gas chromatograph and time-of-flight mass spectrometer to perform analysis of soil samples and determine the content of volatile components.[38][39]
Ptolemy 
An instrument measuring stable isotope ratios of key volatiles on the comet's nucleus.[40][41]
ÇIVA 
The Comet Nucleus Infrared and Visible Analyzer is a group of six identical micro-cameras that take panoramic pictures of the surface. Each camera has a 1024×1024 pixel CCD detector.[42] A spectrometer studies the composition, texture and albedo (reflectivity) of samples collected from the surface.[43]
ROLIS 
The Rosetta Lander Imaging System is a CCD camera that will obtain high-resolution images during descent and stereo panoramic images of areas sampled by other instruments.[44] The CCD detector consists of 1024×1024 pixels.[45]
CONSERT
The COmet Nucleus Sounding Experiment by Radiowave Transmission experiment will use electromagnetic wave propagation to determine the comet's internal structure. A radar on Rosetta will transmit a signal through the nucleus to be received by a detector on Philae.[46][47]
MUPUS 
The MUlti-PUrpose Sensors for Surface and Sub-Surface Science instrument will measure the density, thermal and mechanical properties of the comet's surface.[48]
ROMAP 
The Rosetta Lander Magnetometer and Plasma Monitor is a magnetometer and plasma sensor to study the nucleus' magnetic field and its interactions with the solar wind.[49]
SESAME 
The Surface Electric Sounding and Acoustic Monitoring Experiments will use three instruments to measure properties of the comet's outer layers. The Cometary Acoustic Sounding Surface Experiment (CASSE) measures the way in which sound travels through the surface. The Permittivity Probe (PP) investigates its electrical characteristics, and the Dust Impact Monitor (DIM) measures dust falling back to the surface.[50]
SD2 
The Drill, Sample, and Distribution subsystem obtains soil samples from the comet at depths of 0 to 230 millimetres (0.0 to 9.1 in) and distributes them to the Ptolemy, COSAC, and ÇIVA subsystems for analyses.[51] The system contains four types of subsystems: drill, carousel, ovens, and volume checker.[52] There are a total of 26 platinum ovens to heat samples—10 medium temperature 180 °C (356 °F) and 16 high temperature 800 °C (1,470 °F)—and one oven to clear the drill bit for reuse.[53]

International contributions

Austria 
The Austrian Space Research Institute developed the lander's anchor and two sensors within MUPUS, which are integrated into the anchor tips. They indicate the temperature variations and the shock acceleration.
Belgium 
The Belgian Institute for Space Aeronomy (BIRA) cooperated with different partners to build one of the sensors (DFMS) of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument.[54][55]
Finland 
The Finnish Meteorological Institute provided the Memory of the Command, Data and Management System (CDMS) and the Permittivity Probe (PP).
France 
The French Space Agency together with some scientific laboratories (IAS, SA, LPG, LISA) provided the system's overall engineering, radiocommunications, battery assembly, CONSERT, ÇIVA and the ground segment (overall engineering and development/operation of the Scientific Operation & Navigation Centre).
Germany 
The German Space Agency (DLR) has provided the structure, thermal subsystem, flywheel, the Active Descent System (procured by DLR but made in Switzerland),[56] ROLIS, downward-looking camera, SESAME, acoustic sounding and seismic instrument for Philae. It has also managed the project and did the level product assurance. The University of Münster built MUPUS (it was designed and built in Space Research Centre of Polish Academy of Sciences [57]) and the Braunschweig University of Technology the ROMAP instrument. The Max Planck Institute for Solar System Research made the payload engineering, eject mechanism, landing gear, anchoring harpoon, central computer, COSAC, APXS and other subsystems.
Hungary 
The Command and Data Management Subsystem (CDMS) designed in the Wigner Research Centre for Physics of the Hungarian Academy of Sciences. The Power Subsystem (PSS) designed in the Department of Broadband Infocommunications and Electromagnetic Theory at Budapest University of Technology and Economics. CDMS is the fault tolerant central computer of the lander, while PSS assures that the power coming from the batteries and solar arrays are properly handled, controls battery charging and manages the onboard power distribution.
Italy 
The Italian Space Agency (ASI) has provided the SD2 instrument and the Photo Voltaic Assembly. The industrial contractors are respectively Tecnospazio SpA and Galileo Avionica SpA.
Ireland 
Space Technology Ireland Ltd. at Maynooth University has designed, constructed and tested the Electrical Support System Processor Unit (ESS) for the Rosetta mission. ESS stores, transmits and provides decoding for the command streams passing from the spacecraft to the lander and handles the data streams coming back from the scientific experiments on the lander to the spacecraft.
Netherlands
Moog Bradford (Heerle, The Netherlands) provided the Active Descent System (ADS) that is intended to provide the required impulse to ensure that Philae will descend towards the nucleus of comet 67P/Churyumov-Gerasimenko in 2014. To accomplish the ADS, a strategic industrial team was formed with Bleuler-Baumer Mechanik in Switzerland.[56]
Poland 
The Space Research Centre of the Polish Academy of Sciences built the Multi-Purpose Sensors for Surface and Subsurface Science (MUPUS).[57]
Spain 
The Instituto de Astrofísica de Andalucía and the Spanish National Research Council of Madrid have contributed to the mission of designing and manufacturing the ship's medium-gain antenna system, thermal control antennas and the Osiris camera,[58] while its Center in Tres Cantos (Madrid) has developed and manufactured the Star Tracker and the navigation camera control units. The GMV Spanish division has been responsible for the maintenance of the calculation tools to calculate the criteria of lighting and visibility necessary to decide the point of landing on the comet, as well as the possible trajectories of decline of the Philae module. SENER, a Spanish Aeronautics and Engineering Company, was responsible for the supply of two deployable masts, 15 shades of active thermal control and electronic control of all the Giada instrument unit, optical displays of attenuation of incident radiation on two navigation cameras and the two star trackers, and the driver of the filter wheel of cameras NAC and WAC of the Osiris instrument (the instrument onboard Rosetta ship to photographed the Comet), among other components. The Crisa group has provided the electronic unit from the star browser and navigation camera; a division of the Elecnor group Deimos Space, which has defined the path to reach the destination. Other important Spanish companies or educational institutions that have been contributed are as follows: INTA, Airbus Defence and Space Spanish division, and the Universidad Politécnica de Madrid.[58]
Switzerland 
The Swiss Center for Electronics and Microtechnology developed ÇIVA.[59]
United Kingdom 
The Open University and the Rutherford Appleton Laboratory (RAL) have developed PTOLEMY. RAL has also constructed the blankets that keep the lander warm throughout its mission. Surrey Satellites Technology Ltd. (SSTL) constructed the reaction wheel for the lander. It stabilises the module during the descent and landing phases.[58] Manufacturer e2v supplied the Civa and Rolis camera systems used to film the descent and take images of samples, as well as three other camera systems.[60]

In popular culture

On 12 November 2014, to commemorate the first controlled touchdown of Philae on a comet nucleus, the search engine Google featured a Google Doodle on its home page.[61][62]

Vangelis composed the music for the trio of music videos released by ESA to celebrate the first ever attempted soft landing on a comet by ESA's Rosetta mission.[63][64][65]

"A Webcomic of Romance, Sarcasm, Math, and Language," xkcd, by Randall Munroe[66] covered the landing.[67]

Gallery

  • Depiction of Philae '​s touchdown on the comet

  • Philae '​s foot screws

  • Rosetta signal received at ESOC in Darmstadt, Germany (January 20, 2014)

See also

References

Notes

  1. ^ Jump up to: a b c d "PHILAE". National Space Science Data Center. Retrieved 28 January 2014. 
  2. Jump up ^ "Philae lander fact sheet" (PDF). DLR. Retrieved 28 January 2014. 
  3. Jump up ^ Philae. Dictionary.com. Dictionary.com Unabridged. Random House, Inc. (accessed: November 13, 2014).
  4. Jump up ^ Ellis, Ralph (12 November 2014). "Space probe scores a 310-million-mile bull's-eye with comet landing" (pronunciation used in video). cnn.com. CNN. Retrieved 13 November 2014. 
  5. Jump up ^ Chang, Kenneth (5 August 2014). "Rosetta Spacecraft Set for Unprecedented Close Study of a Comet". The New York Times. Retrieved 5 August 2014. 
  6. Jump up ^ Ulamec, S.; Espinasse, S.; Feuerbacher, B.; Hilchenbach, M.; Moura, D. et al. (April 2006). "Rosetta Lander—Philae: Implications of an alternative mission". Acta Astronautica 58 (8): 435–441. Bibcode:2006AcAau..58..435U. doi:10.1016/j.actaastro.2005.12.009. 
  7. ^ Jump up to: a b Biele, Jens (2002). "The Experiments Onboard the ROSETTA Lander". Earth, Moon, and Planets 90 (1–4): 445–458. Bibcode:2002EM&P...90..445B. doi:10.1023/A:1021523227314. 
  8. Jump up ^ Agle, D. C.; Cook, Jia-Rui; Brown, Dwayne; Bauer, Markus (17 January 2014). "Rosetta: To Chase a Comet". NASA. Retrieved 18 January 2014. 
  9. Jump up ^ Agle, DC; Webster, Guy; Brown, Dwayne; Bauer, Markus (12 November 2014). "Rosetta's 'Philae' Makes Historic First Landing on a Comet". NASA. Retrieved 13 November 2014. 
  10. Jump up ^ Chang, Kenneth (12 November 2014). "European Space Agency’s Spacecraft Lands on Comet’s Surface". The New York Times. Retrieved 12 November 2014. 
  11. Jump up ^ "Europe's Comet Chaser – Historic mission". European Space Agency. 16 January 2014. Retrieved 5 August 2014. 
  12. Jump up ^ ESOC at ESA website, retrieved 13 November 2014
  13. ^ Jump up to: a b Gilpin, Lyndsey (14 August 2014). "The tech behind the Rosetta comet chaser: From 3D printing to solar power to complex mapping". TechRepublic. 
  14. ^ Jump up to: a b c Bibring, J.-P.; Rosenbauer, H.; Boehnhardt, H.; Ulamec, S.; Biele, J. et al. (February 2007). "The Rosetta Lander ("Philae") Investigations". Space Science Reviews 128 (1–4): 205–220. Bibcode:2007SSRv..128..205B. doi:10.1007/s11214-006-9138-2. 
  15. Jump up ^ http://astronomynow.com/2014/11/11/top-ten-rosetta-images-from-10km/
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  17. Jump up ^ Bauer, Markus (15 September 2014). "'J' Marks the Spot for Rosetta's Lander". European Space Agency. Retrieved 20 September 2014. 
  18. ^ Jump up to: a b "Will Philae successfully land on comet? Thruster trouble heightens drama.". Christian Science Monitor. 12 November 2014. 
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  24. Jump up ^ Aron, Jacob. "Problems hit Philae after historic first comet landing" New Scientist
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  26. Jump up ^ "Philae probe may have 'landed twice' without anchoring to comet". BBC. 12 November 2014. 
  27. Jump up ^ Beatty, J. K. (2014-11-12). "Philae Lands on Its Comet — Three Times!". Sky and Telescope. Retrieved 2014-11-12. 
  28. Jump up ^ Lakdawalla, E. S. (2014-11-12). "Philae Has Landed! [Updated]". Planetary Society blog. The Planetary Society. Archived from the original on 13 November 2014. Retrieved 2014-11-13. 
  29. Jump up ^ Djursing, Thomas. "Kometsonden Philae står skævt under en klippe og får for lidt sollys" English translation Ingeniøren, 13 November 2014.
  30. Jump up ^ "Is Rosetta's comet lander doomed? Scientists have just 24 hours left to save the solar-powered probe after it lands at the bottom of a CLIFF in darkness". Daily Mail. 13 November 2014. Retrieved 13 November 2014. 
  31. Jump up ^ Amos, Jonathan (26 September 2014). "Rosetta: Date fixed for historic comet landing attempt". BBC News. Retrieved 29 September 2014. 
  32. Jump up ^ Amos, Jonathan (25 August 2014). "Rosetta mission: Potential comet landing sites chosen". BBC News. Retrieved 25 August 2014. 
  33. Jump up ^ Conzo, Giuseppe (2 September 2014). "The Analysis of Comet 67P/Churyumov-Gerasimenko". Astrowatch.net. Retrieved 4 October 2014. 
  34. Jump up ^ Böhnhardt, Hermann (10 November 2014). "About the Upcoming Philae Separation, Descent and Landing". Max Planck Institute for Solar System Research. Retrieved 11 November 2014. 
  35. Jump up ^ Biele, J.; Ulamec, S.; Richter, L.; Kührt, E.; Knollenberg, J.; Möhlmann, D. (2009). "The Strength of Cometary Surface Material: Relevance of Deep Impact Results for Philae Landing on a Comet". In Käufl, Hans Ulrich; Sterken, Christiaan. Deep Impact as a World Observatory Event: Synergies in Space, Time, and Wavelength. ESO Astrophysics Symposia. Springer. p. 297. Bibcode:2009diwo.conf..285B. doi:10.1007/978-3-540-76959-0_38. ISBN 978-3-540-76958-3. 
  36. Jump up ^ Biele, Jens; Ulamec, Stephan (2013). "Preparing for Landing on a Comet – The Rosetta Lander Philae". 44th Lunar and Planetary Science Conference. 18–22 March 2013. The Woodlands, Texas. Bibcode:2013LPI....44.1392B. LPI Contribution No. 1719. 
  37. Jump up ^ "APXS". European Space Agency. Retrieved 26 August 2014. 
  38. Jump up ^ Goesmann, Fred; Rosenbauer, Helmut; Roll, Reinhard; Böhnhardt, Hermann (October 2005). "COSAC Onboard Rosetta: A Bioastronomy Experiment for the Short-Period Comet 67P/Churyumov-Gerasimenko". Astrobiology 5 (5): 622–631. Bibcode:2005AsBio...5..622G. doi:10.1089/ast.2005.5.622. PMID 16225435. 
  39. Jump up ^ "COSAC". European Space Agency. Retrieved 26 August 2014. 
  40. Jump up ^ Wright, I. P.; Barber, S. J.; Morgan, G. H.; Morse, A. D.; Sheridan, S. et al. (February 2007). "Ptolemy: An Instrument to Measure Stable Isotopic Ratios of Key Volatiles on a Cometary Nucleus". Space Science Reviews 128 (1–4): 363–381. Bibcode:2007SSRv..128..363W. doi:10.1007/s11214-006-9001-5. 
  41. Jump up ^ Andrews, D. J.; Barber, S. J.; Morse, A. D.; Sheridan, S.; Wright, I. P. et al. (2006). "Ptolemy: An Instrument aboard the Rosetta Lander Philae, to Unlock the Secrets of the Solar System". 37th Lunar and Planetary Science Conference. 13–17 March 2006. League City, Texas. 
  42. Jump up ^ "Comet nucleus Infrared and Visible Analyzer (CIVA)". National Space Science Data Center. Retrieved 28 August 2014. 
  43. Jump up ^ "ÇIVA". European Space Agency. Retrieved 26 August 2014. 
  44. Jump up ^ "ROLIS". European Space Agency. Retrieved 26 August 2014. 
  45. Jump up ^ "Rosetta Lander Imaging System (ROLIS)". National Space Science Data Center. Retrieved 28 August 2014. 
  46. Jump up ^ Kofman, W.; Herique, A.; Goutail, J.-P.; Hagfors, T.; Williams, I. P. et al. (February 2007). "The Comet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT): A Short Description of the Instrument and of the Commissioning Stages". Space Science Reviews 128 (1–4): 413–432. Bibcode:2007SSRv..128..413K. doi:10.1007/s11214-006-9034-9. 
  47. Jump up ^ "CONCERT". European Space Agency. Retrieved 26 August 2014. 
  48. Jump up ^ "MUPUS". European Space Agency. Retrieved 26 August 2014. 
  49. Jump up ^ "ROMAP". European Space Agency. Retrieved 26 August 2014. 
  50. Jump up ^ Seidensticker, K. J.; Möhlmann, D.; Apathy, I.; Schmidt, W.; Thiel, K. et al. (February 2007). "Sesame – An Experiment of the Rosetta Lander Philae: Objectives and General Design". Space Science Reviews 128 (1–4): 301–337. Bibcode:2007SSRv..128..301S. doi:10.1007/s11214-006-9118-6. 
  51. Jump up ^ "SD2". European Space Agency. Retrieved 26 August 2014. 
  52. Jump up ^ "Philae SD2". Politecnico di Milano. Retrieved 11 August 2014. 
  53. Jump up ^ "Ovens". Politecnico di Milano. Retrieved 11 August 2014. 
  54. Jump up ^ Christiaens, Kris (6 November 2014). "België mee aan boord van Rosetta kometenjager". Belgium in Space.be (in Dutch). Retrieved 13 November 2014. 
  55. Jump up ^ Christiaens, Kris (19 July 2009). "Rosetta". Belgium in Space.be (in Dutch). Retrieved 13 November 2014. 
  56. ^ Jump up to: a b "Active Descent System". Moog Inc. Retrieved 11 November 2014. 
  57. ^ Jump up to: a b "The MUPUS Instrument for Rosetta mission to comet Churyumov-Gerasimenko". Laboratorium Mechatroniki i Robotyki Satelitarnej. 2014. Retrieved 6 August 2014. 
  58. ^ Jump up to: a b c "IAA-CSIC is co-managing an instrument that will orbit around the Sun on board the Solar Orbiter mission ESA". Instituto de Astrofísica de Andalucía. 2014. Retrieved 11 November 2014. 
  59. Jump up ^ "CIVA Project". 2014. Retrieved 7 November 2014. 
  60. Jump up ^ Alan Tovey (11 November 2014). "UK space industry behind Rosetta comet mission". The Telegraph. 
  61. Jump up ^ Solon, Olivia (12 November 2014). "Philae: Google Doodle marks Rosetta's historic comet landing". Mirror. Retrieved 12 November 2014. 
  62. Jump up ^ "Google Doodles". Google. 12 November 2014. Retrieved 12 November 2014. 
  63. Jump up ^ https://www.youtube.com/watch?v=FJrUnzLsmZk
  64. Jump up ^ https://www.youtube.com/watch?v=W8bVOGN9jSg
  65. Jump up ^ https://www.youtube.com/watch?v=PUpSVxoCcik
  66. Jump up ^ http://www.xkcd.com/about/
  67. Jump up ^ http://xkcd.com/1446/#

Further reading

External links

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