Европейская миссия к комете Чурюмова-Герасименко

European orbiter sent to study a comet

Rosetta was a space probe built by the European Space Agency launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a detailed study of comet 67P/Churyumov–Gerasimenko (67P). During its journey to the comet, the spacecraft performed flybys of Earth, Mars, and the asteroids 21 Lutetia and 2867 Šteins. On 30 September 2016, the Rosetta spacecraft ended its mission by hard landing on the comet in its Ma'at region. The probe was named after the Rosetta Stone, a stele of Egyptian origin featuring a decree in three scripts. The lander was named after the Philae obelisk, which bears a bilingual Greek and Egyptian hieroglyphic inscription.

Rosetta was launched on 2 March 2004 from the Guiana Space Centre in Kourou, French Guiana, on an Ariane 5 rocket and reached Comet Churyumov–Gerasimenko on 7 May 2014. It performed a series of manoeuvres to enter orbit between then and 6 August 2014, (Previous missions had conducted successful flybys of seven other comets.) It was one of ESA's Horizon 2000 cornerstone missions. The spacecraft consisted of the Rosetta orbiter, which featured 12 instruments, and the Philae lander, with nine additional instruments. The Rosetta mission orbited Comet Churyumov–Gerasimenko for 17 months and was designed to complete the most detailed study of a comet ever attempted. The spacecraft was controlled from the European Space Operations Centre (ESOC), in Darmstadt, Germany. The planning for the operation of the scientific payload, together with the data retrieval, calibration, archiving and distribution, was performed from the European Space Astronomy Centre (ESAC), in Villanueva de la Cañada, near Madrid, Spain. It has been estimated that in the decade preceding 2014, some 2,000 people assisted in the mission in some capacity. The spacecraft also performed two asteroid flybys. The craft completed its flyby of asteroid 2867 Šteins in September 2008 and of 21 Lutetia in July 2010. Later, on 20 January 2014, Rosetta was taken out of a 31 month hibernation mode as it approached Comet Churyumov–Gerasimenko. Rosetta Philae lander successfully made the first soft landing on a comet nucleus when it touched down on Comet Churyumov–Gerasimenko on 12 November 2014. On 5 September 2016, ESA announced that the lander was discovered by the narrow angle camera aboard Rosetta as the orbiter made a low, pass over the comet. The lander sits on its side wedged into a dark crevice of the comet, explaining the lack of electrical power to establish proper communication with the orbiter.

During the 1986 approach of Halley's Comet, international space probes were sent to explore the comet, most prominent among them being ESA's Giotto. After the probes returned valuable scientific information, it became obvious that follow ons were needed that would shed more light on cometary composition and answer new questions. Both ESA and NASA started cooperatively developing new probes. The NASA project was the Comet Rendezvous Asteroid Flyby (CRAF) mission. The ESA project was the follow on Comet Nucleus Sample Return (CNSR) mission. Both missions were to share the Mariner Mark II spacecraft design, thus minimising costs. In 1992, after NASA cancelled CRAF due to budgetary limitations, ESA decided to develop a CRAF style project on its own. By 1993 it was evident that the ambitious sample return mission was infeasible with the existing ESA budget, so the mission was redesigned and subsequently approved by the ESA, with the final flight plan resembling the cancelled CRAF mission: an asteroid flyby followed by a comet rendezvous with in situ examination, including a lander. The Rosetta mission included generational team management; this allowed mission continuity over the long period of the mission and for special knowledge to be maintained and passed on to future team members. In particular, several younger scientists were brought on as principal science investigators, and regular training sessions were conducted. a stele of Egyptian origin featuring a decree in three scripts. The lander was named after the Philae obelisk, which bears a bilingual Greek and Egyptian hieroglyphic inscription. A comparison of its hieroglyphs with those on the Rosetta Stone catalysed the deciphering of the Egyptian writing system. Similarly, it was hoped that these spacecraft would result in better understanding of comets and the early Solar System. In a more direct analogy to its namesake, the Rosetta spacecraft also carried a micro etched pure nickel prototype of the Rosetta disc donated by the Long Now Foundation. The disc was inscribed with 6,500 pages of language translations.

The Rosetta mission achieved many historic firsts. On its way to comet 67P, Rosetta passed through the main asteroid belt, and made the first European close encounter with several of these primitive objects. Rosetta was the first spacecraft to fly close to Jupiter's orbit using solar cells as its main power source. Rosetta was the first spacecraft to orbit a comet nucleus, and was the first spacecraft to fly alongside a comet as it headed towards the inner Solar System. It became the first spacecraft to examine at close proximity the activity of a frozen comet as it is warmed by the Sun. Shortly after its arrival at 67P, the Rosetta orbiter dispatched the Philae lander for the first controlled touchdown on a comet nucleus. The robotic lander's instruments obtained the first images from a comet's surface and made the first in situ analysis of its composition.

The Rosetta bus was a central frame and aluminium honeycomb platform. Its total mass was approximately , which included the Philae lander and of science instruments. The Payload Support Module was mounted on top of the spacecraft and housed the scientific instruments, while the Bus Support Module was on the bottom and contained spacecraft support subsystems. Heaters placed around the spacecraft kept its systems warm while it was distant from the Sun. Rosetta communications suite included a steerable high gain parabolic dish antenna, a fixed position medium gain antenna, and two omnidirectional low gain antennas. Electrical power for the spacecraft came from two solar arrays totalling Each solar array was subdivided into five solar panels, with each panel being The individual solar cells were made of silicon, 200 μm thick, and The solar arrays generated a maximum of approximately 1,500 watts at perihelion, and was stored in four 10 A·h [Li ion] batteries supplying 28 volts to the bus. Rosetta was built in a clean room according to COSPAR rules, but "sterilisation generally not crucial since comets are usually regarded as objects where you can find prebiotic molecules, that is, molecules that are precursors of life, but not living microorganisms", according to Gerhard Schwehm, Rosetta project scientist. The total cost of the mission was about €1.3 billion (US$1.8 billion).

Rosetta was set to be launched on 12 January 2003 to rendezvous with the comet 46P/Wirtanen in 2011. In May 2003, a new plan was formed to target the comet 67P/Churyumov–Gerasimenko, with a revised launch date of 26 February 2004 and comet rendezvous in 2014. The larger mass and the resulting increased impact velocity made modification of the landing gear necessary. After two scrubbed launch attempts, Rosetta was launched on 2 March 2004 at 07:17 UTC from the Guiana Space Centre in French Guiana, using Ariane 5 G+ carrier rocket.

To achieve the required velocity to rendezvous with 67P, Rosetta used gravity assist manoeuvres to accelerate throughout the inner Solar System. The comet's orbit was known before Rosetta launch, from ground based measurements, to an accuracy of approximately Information gathered by the onboard cameras beginning at a distance of were processed at ESA's Operation Centre to refine the position of the comet in its orbit to a few kilometres. The first Earth flyby was on 4 March 2005. During that encounter, the solar panels could not be used since the craft was in the planet's shadow, where it would not receive any solar light for 15 minutes, causing a dangerous shortage of power. The craft was therefore put into standby mode, with no possibility to communicate, flying on batteries that were originally not designed for this task. This Mars manoeuvre was therefore nicknamed "The Billion Euro Gamble". The flyby was successful, with Rosetta even returning detailed images of the surface and atmosphere of the planet, and the mission continued as planned. In observations made on 7 and 8 November, Rosetta was briefly mistaken for a near Earth asteroid about in diameter by an astronomer of the Catalina Sky Survey and was given the provisional designation Calculations showed that it would pass very close to Earth, which led to speculation that it could impact Earth. However, astronomer Denis Denisenko recognised that the trajectory matched that of Rosetta, which the Minor Planet Center confirmed in an editorial release on 9 November. The spacecraft performed a close flyby of asteroid 2867 Šteins on 5 September 2008. Its onboard cameras were used to fine tune the trajectory, achieving a minimum separation of less than Onboard instruments measured the asteroid from 4 August to 10 September. Maximum relative speed between the two objects during the flyby was
Rosetta third and final flyby of Earth happened on 12 November 2009 at a distance of
On 10 July 2010, Rosetta flew by 21 Lutetia, a large main belt asteroid, at a minimum distance of 3168 km (1969 mi) at a velocity of The flyby provided images of up to per pixel resolution and covered about 50% of the surface, mostly in the northern hemisphere. The 462 images were obtained in 21 narrow and broad band filters extending from 0.24 to 1 μm. Prior to Rosetta deep space hibernation period, two of the spacecraft's four reaction wheels began exhibiting increased levels of "bearing friction noise". Increased friction levels in Reaction Wheel Assembly (RWA) B were noted after its September 2008 encounter with asteroid Šteins. Two attempts were made to relubricate the RWA using an on board oil reservoir, but in each case noise levels were only temporarily lowered, and the RWA was turned off in mid 2010 after the flyby of asteroid Lutetia to avoid possible failure. Shortly after this, RWA C also began showing evidence of elevated friction. Relubrication was also performed on this RWA, and methods were found to temporarily increase its operating temperature to better improve the transfer of oil from its reservoir. In addition, the reaction wheel's speed range was decreased to limit lifetime accumulated rotations. These changes resulted in RWA C performance stabilising. During the spacecraft's Deep Space Hibernation flight phase, engineers performed ground testing on a flight spare RWA at the European Space Operations Centre. After Rosetta exited hibernation in January 2014, lessons learned from the ground testing were applied to all four RWAs, such as increasing their operating temperatures and limiting their wheel speeds to below 1000 rpm. After these fixes, the RWAs showed nearly identical performance data. These changes allowed the four RWAs to operate throughout Rosetta mission at 67P/Churyumov–Gerasimenko despite occasional anomalies in their friction plots and a heavy workload imposed by numerous orbital changes. By 25 August 2014, five potential landing sites had been determined. On 15 September 2014, ESA announced Site J, named Agilkia in honour of Agilkia Island by an ESA public contest and located on the "head" of the comet, as the lander's destination.

As the orbit of comet 67P took it farther from the Sun, the amount of sunlight reaching Rosetta solar panels decreased. While it would have been possible to put Rosetta into a second hibernation phase during the comet's aphelion, there was no assurance that enough power would be available to run the spacecraft's heaters to keep it from freezing. To guarantee a maximum science return, mission managers made the decision to instead guide Rosetta down to the comet's surface and end the mission on impact, gathering photographs and instrument readings along the way. On 23 June 2015, at the same time as a mission extension was confirmed, ESA announced that end of mission would occur at the end of September 2016 after two years of operations at the comet. blockquote|All stations and the briefing room, we've just had loss of signal at the expected time. This is another outstanding performance by flight dynamics. So we'll be listening for the signal from Rosetta for another 24 hours, but we don't expect any. This is the end of the Rosetta mission. Thank you, and goodbye. Sylvain Lodiot, Rosetta Spacecraft Operations Manager, European Space Operations Centre Its trajectory targeted a site in the Ma'at region near an area of dust and gas producing active pits. Impact on the comet's surface occurred 14.5 hours after its descent manoeuvre; the final data packet from Rosetta was transmitted at 10:39:28.895 UTC (SCET) by the OSIRIS instrument and was received at the European Space Operations Centre in Darmstadt, Germany, at 11:19:36.541 UTC. The spacecraft's estimated speed at the time of impact was , Rosetta computer included commands to send it into safe mode upon detecting that it had hit the comet's surface, turning off its radio transmitter and rendering it inert in accordance with International Telecommunication Union rules.

ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis). The instrument consisted of a double focus magnetic mass spectrometer (DFMS) and a reflectron type time of flight mass spectrometer (RTOF). The DFMS had a high resolution (could resolve N2 from CO) for molecules up to 300 amu. The RTOF was highly sensitive for neutral molecules and for ions. The Max Planck Institute for Solar System Research (MPS) has contributed to the development and construction of the instrument. ROSINA was developed at the University of Bern in Switzerland. MIDAS (Micro Imaging Dust Analysis System). The high resolution atomic force microscope investigated several physical aspects of the dust particles which are deposited on a silicon plate. COSIMA (Cometary Secondary Ion Mass Analyser). COSIMA analysed the composition of dust particles by secondary ion mass spectrometry, using indium ions. It could detect ions up to a mass of 6500 amu. COSIMA was built by the Max Planck Institute for Extraterrestrial Physics (MPE, Germany) with international contributions. The COSIMA team is led by the Max Planck Institute for Solar System Research (MPS, Germany). GIADA (Grain Impact Analyser and Dust Accumulator). GIADA analysed the dust environment of the comet coma by measuring the optical cross section, momentum, speed and mass of each grain entering inside the instrument.

RPC (Rosetta Plasma Consortium).

As part of the European Space Agency's media campaign in support of the Rosetta mission, both the Rosetta and Philae spacecraft were given anthropomorphic personalities in an animated web series titled Once upon a time The series depicts various stages in the Rosetta mission, involving the personified Rosetta and Philae on "a classic road trip story into the depths of our universe", complemented with various visual gags presented in an educational context. Produced by animation studio Design & Data GmbH, the series was initially conceived by the ESA as a four part fantasy like series with a Sleeping Beauty theme that promoted community involvement in Rosettas wake up from hibernation in January 2014. After the success of the series, however, the ESA commissioned the studio to continue producing new episodes in the series throughout the course of the mission. In 2019, Design & Data adapted the series into a 26 minute planetarium show that was commissioned by the Swiss Museum of Transport, and solicited to eighteen planetariums across Europe, with an aim "to inspire the young generation to explore the universe." The Rosetta and Philae characters featured in Once upon a time , designed by ESA employee and cartoonist Carlo Palazzari, became a central part of public image of the Rosetta mission, appearing in promotional material for the mission such as posters and merchandise, and often credited as a major factor in the popularity of the mission among the public. ESA employees also role played as the characters on Twitter throughout the course of the mission. The characters were inspired by the JAXA's "kawaii" characters, who portrayed a number of their spacecraft, such as Hayabusa2 and Akatsuki, with distinct anime like personalities. The script for each episode of the series is written by science communicators at the European Space Research and Technology Centre, who kept close with mission operators and the producers at Design & Data. Set in the far future, Ambition centers around a discussion between a master, played by Gillen, discussing the importance of ambition with his apprentice, played by Franciosi, using the Rosetta mission as an example of such. Ambition was premiered at the British Film Institute's Sci Fi: Days of Fear and Wonder film festival in London on 24 October 2014, three weeks before the landing of Philae on 67P/Churyumov–Gerasimenko. British science fiction author and former ESA employee Alastair Reynolds spoke about the film's message at the premiere, stating to the audience that "our distant descendants may look back to Rosetta with the same sense of admiration that we reserve for, say, Columbus or Magellan." Critical reception of the film upon its premiere was mostly positive. Tim Reyes of Universe Today complimented the titular theme of ambition in the film, stating that it "shows us the forces at work in and around ESA", and that it "might accomplish more in 7 minutes than Gravity did in 90."

The entire mission was featured heavily in social media, with a Facebook account for the mission and both the satellite and the lander having an official Twitter account portraying a personification of both spacecraft. The hashtag "#CometLanding" gained widespread traction. A Livestream of the control centres was set up, as were multiple official and unofficial events around the world to follow Philae landing on 67P. On 23 September 2016, Vangelis released the studio album Rosetta in honour of the mission, which was used on 30 September in the "Rosetta's final hour" streaming video of the ESA Livestream event "Rosetta Grand Finale".