ESA Solar System insignia for theMars Express mission
Mars Express is aspace exploration mission being conducted by theEuropean Space Agency (ESA). TheMars Express mission is exploring the planetMars, and is the first planetary mission attempted by the agency.[2] "Express" originally referred to the speed and efficiency with which thespacecraft was designed and built.[3] However, "Express" also describes the spacecraft's relatively short interplanetary voyage, a result of being launched when the orbits of Earth and Mars brought them closer than they had been in about 60,000 years.
Mars Express consists of two parts, theMars Express Orbiter andBeagle 2,[4] alander designed to performexobiology and geochemistry research. Although the lander failed to fully deploy after it landed on the Martian surface, the orbiter has been successfully performing scientific measurements since early 2004, namely,high-resolution imaging and mineralogical mapping of the surface, radar sounding of the subsurface structure down to the permafrost, precise determination of theatmospheric circulation and composition, and study of the interaction of theatmosphere with theinterplanetary medium.[4]
Due to the valuable science return and the highly flexible mission profile,Mars Express has been granted several mission extensions. The latest was approved on March 7, 2023, consisting of a confirmed operating period until December 31, 2026, and a further provisional extension to December 31, 2028.[5][6]
Some of the instruments on the orbiter, including the camera systems and somespectrometers, reuse designs from the failed launch of the RussianMars 96 mission in 1996[2] (European countries had provided much of the instrumentation and financing for that unsuccessful mission). The design ofMars Express is based on ESA'sRosetta mission, on which a considerable sum was spent on development. The same design was also used for ESA'sVenus Express mission in order to increase reliability and reduce development cost and time. Because of these redesigns and repurposings, the total cost of the project was about $345 million- less than half of comparable U.S. missions.[7]
Arriving at Mars in 2003, 21 years, 3 months and 11 days ago (and counting), it is the second longest surviving, continually active spacecraft in orbit around a planet other than Earth, behind only NASA's still active2001 Mars Odyssey.
TheMars Express mission is dedicated to the orbital (and originally in-situ) study of the interior, subsurface, surface and atmosphere, and environment of the planet Mars.The scientific objectives of theMars Express mission represent an attempt to fulfill in part the lost scientific goals of the RussianMars 96 mission, complemented by exobiology research with Beagle-2. Mars exploration is crucial for a better understanding of the Earth from the perspective ofcomparative planetology.
The spacecraft originally carried seven scientific instruments, a small lander, a lander relay and a Visual Monitoring Camera, all designed to contribute to solving the mystery of Mars' missing water. All of the instruments take measurements of the surface, atmosphere and interplanetary media, from the main spacecraft in polar orbit, which will allow it to gradually cover the whole planet.
The total initialMars Express budget excluding the lander was€150 million.[8][9] The prime contractor for the construction ofMars Express orbiter wasEADS Astrium Satellites.
In the years preceding the launch of a spacecraft numerous teams of experts distributed over the contributing companies and organisations prepared the space and ground segments. Each of these teams focussed on the area of its responsibility and interfacing as required. A major additional requirement raised for the Launch and Early Orbit Phase (LEOP) and all critical operational phases was that it was not enough merely to interface; the teams had to be integrated into one Mission Control Team. All the different experts had to work together in an operational environment and the interaction and interfaces between all elements of the system (software, hardware and human) had to run smoothly for this to happen:
the flight operations procedures had to be written and validated down to the smallest detail;
Animation of Mars Express's trajectory around Sun Mars Express· Sun· Earth· Mars
The spacecraft was launched on June 2, 2003, at 23:45 local time (17:45 UT, 1:45 p.m. EDT) fromBaikonur Cosmodrome inKazakhstan, using aSoyuz-FG/Fregat rocket. TheMars Express and Fregat booster were initially put into a 200 km Earthparking orbit, then the Fregat was fired again at 19:14 UT to put the spacecraft into a Mars transfer orbit. The Fregat andMars Express separated at approximately 19:17 UT. Thesolar panels were then deployed and a trajectory correction manoeuvre was performed on June 4 to aimMars Express towards Mars and allow the Fregat booster to coast into interplanetary space. TheMars Express was the first Russian-launched probe to successfully make it out of low Earth orbit since the Soviet Union fell.
The Near Earth commissioning phase extended from the separation of the spacecraft from the launcher upper stage until the completion of the initial check out of the orbiter and payload. It included the solar array deployment, the initial attitude acquisition, the declamping of the Beagle-2 spin-up mechanism, the injection error correction manoeuvre and the first commissioning of the spacecraft and payload (final commissioning of payload took place after Mars Orbit Insertion). The payload was checked out one instrument at a time. This phase lasted about one month.
This five month phase lasted from the end of the Near Earth Commissioning phase until one month prior to the Mars capture manoeuvre and included trajectory correction manoeuvres and payloads calibration. The payload was mostly switched off during the cruise phase, with the exception of some intermediate check-outs.Although it was originally meant to be a "quiet cruise" phase, It soon became obvious that this "cruise" would be indeed very busy. There werestar tracker problems, a power wiring problem, extra manoeuvres, and on October 28, the spacecraft was hit by one of the largestsolar flares ever recorded.
TheBeagle 2 lander was released on December 19, 2003, at 8:31 UTC (9:31 CET) on aballistic cruise towards the surface. It entered Mars' atmosphere on the morning of December 25. Landing was expected to occur at about 02:45 UT on December 25 (9:45 p.m. EST December 24). However, after repeated attempts to contact the lander failed using theMars Express craft and theNASAMars Odyssey orbiter, it was declared lost on February 6, 2004, by the Beagle 2 management board. An inquiry was held and its findings were published later that year.[10]
Artist's impression of the expected appearance ofMars Express at the time of the Mars Global Surveyor image
Mars Express arrived at Mars after a 400 million km journey and course corrections in September and in December 2003.
On December 20Mars Express fired a short thruster burst to put it into position to orbit the planet. TheMars Express orbiter then fired its main engine and went into a highly elliptical initial-capture orbit of 250 km × 150,000 km with an inclination of 25 degrees on December 25 at 03:00 UT (10:00 p.m., December 24 EST).
First evaluation of the orbital insertion showed that the orbiter had reached its first milestone at Mars. The orbit was later adjusted by four more main engine firings to the desired 259 km × 11,560 km near-polar (86 degree inclination) orbit with a period of 7.5 hours. Nearperiapsis (nearest to Mars) the top deck is pointed down towards the Martian surface and nearapoapsis (farthest from Mars in its orbit) the high gain antenna will be pointed towards Earth for uplink and downlink.
After 100 days the apoapsis was lowered to 10,107 km and periapsis raised to 298 km to give an orbital period of 6.7 hours.
Illustration ofMars Express with MARSIS antenna deployed
On May 4, 2005,Mars Express deployed the first of its two 20-metre-longradar booms for itsMARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) experiment. At first the boom did not lock fully into place; however, exposing it to sunlight for a few minutes on May 10 fixed the glitch. The second 20 m boom was successfully deployed on June 14. Both 20 m booms were needed to create a 40 mdipole antenna for MARSIS to work; a less crucial 7-meter-long monopole antenna was deployed on June 17. The radar booms were originally scheduled to be deployed in April 2004, but this was delayed out of fear that the deployment could damage the spacecraft through a whiplash effect. Due to the delay it was decided to split the four-week commissioning phase in two parts, with two weeks running up to July 4 and another two weeks in December 2005.
The deployment of the booms was a critical and highly complex task requiring effective inter-agency cooperation ESA, NASA, industry and public universities.
Nominal science observations began during July 2005.
Operations forMars Express are carried out by a multinational team of engineers from ESA's Operation Centre (ESOC) inDarmstadt. The team began preparations for the mission about 3 to 4 years prior to the actual launch. This involved preparing the ground segment and the operational procedures for the whole mission.
The Mission Control Team is composed of the Flight Control Team, Flight Dynamics Team, Ground Operations Managers, Software Support and Ground Facilities Engineers. All of these are located at ESOC but there are additionally external teams, such as the Project and Industry Support teams, who designed and built the spacecraft.The Flight Control Team currently consists of:
The Spacecraft Operations Manager
Six Operations Engineers (including three Mission Planners)
The team build-up, headed by the Spacecraft Operations Manager, started about four years before launch. He was required to recruit a suitable team of engineers that could handle the varying tasks involved in the mission. ForMars Express the engineers came from various other missions. Most of them had been involved with Earth orbiting satellites.
Since orbit insertionMars Express has been progressively fulfilling its original scientific goals. Nominally the spacecraft points to Mars while acquiring science and then slews to Earth-pointing to downlink the data, although some instruments like Marsis or Radio Science might be operated while spacecraft is Earth-pointing.
TheMars Express orbiter is a cube-shaped spacecraft with twosolar panel wings extending from opposite sides. The launch mass of 1223 kg includes a main bus with 113 kg of payload, the 60 kg lander, and 457 kg of propellant. The main body is 1.5 m × 1.8 m × 1.4 m in size, with an aluminium honeycomb structure covered by an aluminium skin. The solar panels measure about 12 m tip-to-tip. Two 20 m long wiredipole antennas extend from opposite side faces perpendicular to the solar panels as part of the radar sounder.[11]
The Soyuz/Fregat launcher provided most of the thrustMars Express needed to reach Mars. The final stage of the Soyuz, Fregat was jettisoned once the probe was safely on a course for Mars. The spacecraft's on-board means of propulsion was used to slow the probe for Mars orbit insertion and subsequently for orbit corrections.[11]
The body is built around the main propulsion system, which consists of abipropellant 400N main engine. The two 267-liter propellant tanks have a total capacity of 595 kg. Approximately 370 kg are needed for the nominal mission. Pressurized helium from a 35-liter tank is used to force fuel into the engine. Trajectory corrections will be made using a set of eight 10 N thrusters, one attached to each corner of the spacecraft bus. The spacecraft configuration is optimized for a Soyuz/Fregat, and was fully compatible with aDelta II launch vehicle.
Spacecraft power is provided by the solar panels which contain 11.42 square meters of silicon cells. The originally planned power was to be 660W at 1.5AU but a faulty connection has reduced the amount of power available by 30%, to about 460W. This loss of power does not significantly affect the science return of the mission. Power is stored in threelithium-ion batteries with a total capacity of 64.8Ah for use during eclipses. The power is fully regulated at 28V, and theTerma power module (also used inRosetta) is redundant.[12][13] During routine phase, the spacecraft's power consumption is in the range of 450–550W.[14]
Attitude control (3-axis stabilization) is achieved using two 3-axis inertial measurement units, a set of twostar cameras and twoSun sensors,gyroscopes,accelerometers, and four 12 N·m·sreaction wheels. Pointing accuracy is 0.04 degree with respect to the inertial reference frame and 0.8 degree with respect to the Mars orbital frame. Three on-board systems helpMars Express maintain a very precise pointing accuracy, which is essential to allow the spacecraft to use some of the science instruments.
The communications subsystem is composed of three antennas: A 1.6 m diameter parabolic dishhigh-gain antenna and two omnidirectional antennas. The first one provide links (telecommands uplink and telemetry downlink) in bothX-band (8.4 GHz) andS-band (2.1 GHz) and is used during nominal science phase around Mars. The low gain antennas are used during launch and early operations to Mars and for eventual contingencies once in orbit. Two Mars lander relay UHF antennas are mounted on the top face for communication with theBeagle 2 or other landers, using a Melacom transceiver.[15]
Although communications with Earth were originally scheduled to take place with the ESA 35-meter wide Ground Station in New Norcia (Australia)New Norcia Station, the mission profile of progressive enhancement and science return flexibility have triggered the use of the ESAESTRACK Ground Stations inCebreros Station,Madrid, Spain andMalargüe Station,Argentina.
In addition, further agreements with NASADeep Space Network have made possible the use of American stations for nominal mission planning, thus increasing complexity but with a clear positive impact in scientific returns.
This inter-agency cooperation has proven effective, flexible and enriching for both sides. On the technical side, it has been made possible (among other reasons) thanks to the adoption of both Agencies of the Standards for Space Communications defined inCCSDS.
Thermal control is maintained through the use of radiators,multi-layer insulation, and actively controlled heaters. The spacecraft must provide a benign environment for the instruments and on-board equipment. Two instruments, PFS and OMEGA, have infrared detectors that need to be kept at very low temperatures (about −180 °C). The sensors on the camera (HRSC) also need to be kept cool. But the rest of the instruments and on-board equipment function best at room temperatures (10–20 °C).
The spacecraft is covered in gold-plated aluminium-tin alloy thermal blankets to maintain a temperature of 10–20 °C inside the spacecraft. The instruments that operate at low temperatures to be kept cold are thermally insulated from this relatively high internal temperature, and emit excess heat into space using attached radiators.[11]
The spacecraft is run by two Control and Data management Units with 12 gigabits[11] of solid state mass memory for storage of data and housekeeping information for transmission. The on-board computers control all aspects of the spacecraft functioning including switching instruments on and off, assessing the spacecraft orientation in space and issuing commands to change it.
Another key aspect of theMars Express mission is itsartificial intelligence tool (MEXAR2).[16] The primary purpose of the AI tool is the scheduling of when to download various parts of the collected scientific data back to Earth, a process which used to take ground controllers a significant amount of time. The new AI tool saves operator time, optimizesbandwidth use on theDSN, prevents data loss, and allows better use of the DSN for other space operations as well. The AI decides how to manage the spacecraft's 12 gigabits of storage memory, when the DSN will be available and not be in use by another mission, how to make the best use of the DSN bandwidth allocated to it, and when the spacecraft will be oriented properly to transmit back to Earth.[16][17]
TheBeagle 2 lander objectives were to characterize the landing site geology, mineralogy, and geochemistry, the physical properties of the atmosphere and surface layers, collect data on Martian meteorology and climatology, and search for possible signatures oflife on Mars. However, the landing attempt was unsuccessful and the lander was declared lost. A Commission of Inquiry onBeagle 2[10] identified several possible causes, including airbag problems, severe shocks to the lander's electronics which had not been simulated adequately before launch, and problems with parts of the landing system colliding; but was unable to reach any firm conclusions. The spacecraft's fate remained a mystery until it was announced in January 2015 that NASA's Mars Reconnaissance Orbiter, using HiRISE, had found the probe intact on the surface of Mars. It was then determined that an error had prevented two of the spacecraft's four solar panels from deploying, blocking the spacecraft's communications.Beagle 2 was the first British and first European probe to achieve a landing on Mars.
The scientific objectives of theMars Express payload are to obtain global high-resolution photo-geology (10 m resolution), mineralogical mapping (100 m resolution) and mapping of the atmospheric composition, study the subsurface structure, the global atmospheric circulation, and the interaction between the atmosphere and the subsurface, and the atmosphere and the interplanetary medium. The total mass budgeted for the science payload is 116 kg.[18] The payload scientific instruments are:[19]
Visible and Infrared Mineralogical Mapping Spectrometer (OMEGA) (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) – France – Determines mineral composition of the surface up to 100 m resolution. Is mounted inside pointing out the top face.[20] Instrument mass: 28.6 kg[21]
Ultraviolet and Infrared Atmospheric Spectrometer (SPICAM) – France – Assesses elemental composition of the atmosphere. Is mounted inside pointing out the top face. Instrument mass: 4.7 kg[21]
Sub-Surface Sounding Radar Altimeter (MARSIS) – Italy – A radaraltimeter used to assess composition of sub-surface aimed at search for frozen water. Is mounted in the body and is nadir pointing, and also incorporates the two 20 m antennas. Instrument mass: 13.7 kg[21]
Planetary Fourier Spectrometer (PFS) – Italy – Makes observations of atmospheric temperature and pressure (observations suspended in September 2005). Is mounted inside pointing out the top face[22] and is currently working. Instrument mass: 30.8 kg[21]
Analyzer of Space Plasmas and Energetic Atoms (ASPERA) – Sweden – Investigates interactions between upper atmosphere and solar wind. Is mounted on the top face. Instrument mass: 7.9 kg[21]
High Resolution Stereo Camera (HRSC) – Germany – Produces color images with up to 2 m resolution. Is mounted inside the spacecraft body, aimed through the top face of the spacecraft, which is nadir pointing during Mars operations. Instrument mass: 20.4 kg[21]
Mars Express Lander Communications (MELACOM) – UK – AllowsMars Express to act as a communication relay for landers on the Martian surface. (Has been used on bothMars Exploration Rovers, and was used to support the landing of NASA'sPhoenix mission)
Mars Radio Science Experiment (MaRS) – Uses radio signals to investigate atmosphere, surface, subsurface, gravity and solar corona density during solar conjunctions. It uses the communications subsystem itself.
For more than 20,000 orbits,Mars Express payload instruments have been nominally and regularly operated. The HRSC camera has been consistently mapping the Martian surface with unprecedented resolution and has acquired multiple images.
ESA announced the discovery of water ice in the south polar ice cap, using data collected by the OMEGA instrument.
January 28
Mars Express orbiter reaches final science orbit altitude around Mars.
March 17
Orbiter detects polar ice caps that contain 85%carbon dioxide (CO2) ice and 15% water ice.[23]
March 30
A press release announces that the orbiter has detectedmethane in the Martian atmosphere. Although the amount is small, about 10 parts in a thousand million, it has excited scientists to question its source. Since methane is removed from the Martian atmosphere very rapidly, there must be a current source that replenishes it. Because one of the possible sources could be microbial life, it is planned to verify the reliability of these data and especially watch for difference in the concentration in various places on Mars. It is hoped that the source of this gas can be discovered by finding its location of release.[24]
April 28
ESA announced that the deployment of the boom carrying the radar-based MARSIS antenna was delayed. It described concerns with the motion of the boom during deployment, which can cause the spacecraft to be struck by elements of it. Further investigations are planned to make sure that this will not happen.
July 15
Scientists working with the PFS instrument announced that they tentatively discovered the spectral features of the compoundammonia in the Martian atmosphere. Just like methane discovered earlier (see above), ammonia breaks down rapidly in Mars' atmosphere and needs to be constantly replenished. This points towards the existence of active life or geological activity; two contending phenomena whose presence so far have remained undetected.[25]
In 2005,ESA scientists reported that the OMEGA (Visible and Infrared Mineralogical Mapping Spectrometer)(Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) instrument data indicates the presence of hydrated sulphates, silicates and various rock-forming minerals.[26][27]
February 8
The delayed deployment of the MARSIS antenna has been given a green light by ESA.[28] It is planned to take place in early May 2005.
May 5
The first boom of the MARSIS antenna was successfully deployed.[29] At first, there was no indication of any problems, but later it was discovered that one segment of the boom did not lock.[30] The deployment of the second boom was delayed to allow for further analysis of the problem.
May 11
Using theSun's heat to expand the segments of the MARSIS antenna, the last segment locked in successfully.[31]
June 14
The second boom was deployed, and on June 16 ESA announced it was a success.[32]
June 22
ESA announces that MARSIS is fully operational and will soon begin acquiring data. This comes after the deployment of the third boom on June 17, and a successful transmission test on June 19.[33]
The High Resolution Stereo Camera (HRSC) has obtained images of theCydonia region, the location of the famous "Face on Mars". The massif became famous in a photo taken in 1976 by the AmericanViking 1 Orbiter. The image recorded with a ground resolution of approximately 13.7 metres per pixel.[34]
September 26
TheMars Express spacecraft emerged from an unusually demanding eclipse introducing a special, ultra-low-power mode nicknamed 'Sumo' – an innovative configuration aimed at saving the power necessary to ensure spacecraft survival.
This mode was developed through teamwork between ESOC mission controllers, principal investigators, industry, and mission management.[35]
October
In October 2006 theMars Express spacecraft encountered a superior solar conjunction (alignment of Earth-Sun-Mars-orbiter). The angle Sun-Earth-orbiter reached a minimum on October 23 at 0.39° at a distance of 2.66AU. Operational measures were undertaken to minimize the impact of the link degradation, since the higher density of electrons in the solar plasma heavily impacts the radio frequency signal.[36]
December
Following the loss of NASA'sMars Global Surveyor (MGS),Mars Express team was requested to perform actions in the hopes of visually identifying the American spacecraft. Based on lastephemeris of MGS provided by JPL, the on-board high definition HRSC camera swept a region of the MGS orbit. Two attempts were made to find the craft, both unsuccessful.
Greyscale view of Phobos over Mars, 2007 ESA/DLR/FU Berlin
January
First agreements with NASA undertaken for the support byMars Express on the landing of the American landerPhoenix in May 2008.
February
The small camera VMC (used only once to monitor the lander ejection) was recommissioned and first steps were taken to offer students the possibility to participate in a campaign "Command Mars Express Spacecraft and take your own picture of Mars".
February 23
As result of the science return, the Science Program Committee (SPC) granted a mission extension until May 2009.[37]
June 28
The High Resolution Stereo Camera (HRSC) has produced images of key tectonic features inAeolis Mensae.[38]
Safe mode following a Solid-State Mass Memory problem.[42]
November 24
Science operations are resumed using the Short Mission Timeline and Command Files instead of the Long Time Line resident on the suspect Solid-State Mass Memory.[43]
Takes noted image spanning from the North Pole up toAlba Mons and even farther south.[50] The image was released in December 20, 2017, and was captured by HRSC.[50][51]
December 2018Mars Express relays images of the 80-kilometer wideKorolev Crater filled with approximately 2200 cubic kilometers of water ice on the Martian surface.[57] Based on further evidence the crater ice is still part of much vaster ice resources at Mars poles.[58]
Sept 2020, a discovery is reported based on MARSIS radar studies, of athree more subglacial lakes on Mars, 1.5 km (0.93 mi) below thesouthern polar ice cap. The size of the first lake found, and the largest, has been corrected to 30 km (19 mi) wide. It is surrounded by 3 smaller lakes, each a few kilometres wide.[61]
To celebrate the 20th anniversary of the spacecraft's launch, alivestream of images from theVisual Monitoring Camera was streamed online, marking the first livestream direct from Mars.[67]
^"MEX — ASI-PROC". Planetary Radar Operational Center. March 29, 2016. Archived fromthe original on April 13, 2016. RetrievedMarch 29, 2016.
^"QinetiQ to put Mars in the picture".Qinetiq. Archived fromthe original on August 31, 2006. RetrievedMarch 29, 2016.Consisting of a lightweight bespoke transponder and transceiver weighing less than 650 grams, the system will provide the 10,000-kilometre UHF radio communications link between theMars Express orbiter and Beagle-2 lander.
^Bargery, AS; et al. (2006). "NEAR-INFRARED ANALYSIS OF TEMPE TERRA, OLYMPICA FOSSAE AND NILI FOSSAE FROM OMEGA DATA".Lunar and Planetary Science.XXXVII: 1684.
Missions are ordered by launch date. Sign† indicates failure en route or before intended mission data returned.‡ indicates use of the planet as agravity assist en route to another destination.
Launches are separated by dots ( • ), payloads by commas ( , ), multiple names for the same satellite by slashes ( / ). Crewed flights are underlined. Launch failures are marked with the † sign. Payloads deployed from other spacecraft are (enclosed in parentheses).
Cydonia region
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