ExoMars

ExoMars

Operator	ESA & Russian Federal Space Agency
Major contractors	Orbiter: Thales Alenia Space Rover: Astrium
Mission type	Orbiter, lander and rover
Launch date	2016 and 2018
Launch vehicle	Two Proton rockets
Mission duration	EDM lander: 4 sols Rover: ≥6 months Orbiter: several years
Orbital insertion date	2017 and 2019
Homepage	ExoMars programme
Mass	TGO: 3,130 kg EDM lander: 600 kg Russian lander: ~1800 kg Rover: ~300 kg
Power	TGO: Solar power EDM lander: electric battery Rover: Solar power Russian lander: TBD

ExoMars (Exobiology on Mars) is a large Mars mission to search for biosignatures of Martian life, past or present. This astrobiology mission is currently under development by the European Space Agency (ESA) in collaboration by the Russian Federal Space Agency (Roscosmos). The program includes several spacecraft elements to be sent to Mars on two launches. The ExoMars Trace Gas Orbiter (TGO) and a EDM stationary lander are planned for 2016. The TGO would deliver the ESA-build stationary lander and then proceed to map the sources of methane on Mars and other gases, and in doing so, help select the landing site for the ExoMars rover to be launched on 2018 on a Russian heavy lift Proton launch vehicle. The TGO will feature four instruments and will also act as the communication relay satellite for the follow up rover. In 2018 a Roscosmos-build lander is to deliver the ESA-build rover to the martian surface. The rover will also include some Roscomos build instruments.

Mission history

Since its inception, ExoMars has gone through several phases of planning with various proposals for landers, orbiters, launch vehicles, and international cooperation planning, such as the defunct 2009 Mars Exploration Joint Initiative (MEJI) with the United States. Originally, the ExoMars concept consisted of a large robotic rover being part of ESA's Aurora programme as a Flagship mission and was approved by the European Space Agency ministers in December 2005. Originally conceived as a rover with a stationary ground station, ExoMars was planned to launch in 2011 aboard a Russian Soyuz Fregat rocket.

In 2007, Canadian-based technology firm MacDonald Dettwiler and Associates Ltd. (MDA) was selected for a one-million-euro contract with EADS Astrium of Britain to design and build a prototype Mars rover chassis for the European Space Agency. Astrium was also contracted to design the final rover.

On July 2009 NASA and ESA signed the Mars Joint Exploration Initiative, which proposed to utilize an Atlas rocket launcher instead of a Soyuz, which significantly altered the technical and financial setting of the ExoMars mission. On June 19, when the rover was still planned to piggyback on the Mars Trace Gas Orbiter, it was reported that a prospective agreement would require that ExoMars lose enough weight to fit aboard the Atlas launch vehicle with a NASA orbiter.

Mars Astrobiology Explorer-Cacher (MAX-C) rover

Then the mission was combined with other projects to a multi-spacecraft programme divided over two Atlas V-launches: the ExoMars Trace Gas Orbiter (TGO) was merged into the project, piggybacking a stationary meteorological lander slated for launch in 2016. It was also proposed to include a second rover, the MAX-C.

In August 2009 it was announced that the Russian Federal Space Agency (Roscosmos) and ESA had signed a contract that included cooperation on two Mars exploration projects: Russia's Fobos-Grunt project and ESA's ExoMars. Specifically, ESA secured a Russian Proton rocket as a "backup launcher" for the ExoMars rover, which would include Russian-made parts.

In December 17, 2009, the ESA governments gave their final approval to a two-part Mars exploration programme to be conducted with NASA, confirming their commitment to spend €850 million ($1.23 billion) on missions in 2016 and 2018.

In April 2011, because of a budgeting crisis, a proposal was announced to cancel the accompanying MAX-C rover, and fly only one rover in 2018 that would be larger than either of the vehicles in the paired concept. One suggestion was that the new vehicle would be built in Europe and take a mix of European and U.S. instruments. NASA would provide the rocket to deliver it to Mars and provide the 'Sky Crane' landing system. Despite the proposed reorganisation, the goals of the 2018 mission opportunity would have stayed broadly the same.

Under the FY2013 Budget President Obama released on February 13, 2012, NASA terminated its participation in ExoMars due to budgetary cuts in order to pay for the cost overruns of the James Webb Space Telescope. With NASA's funding for this project completely cancelled, most of these plans had to be restructured.

Current status

On March 14, 2013, representatives of the ESA and the Russian space agency (Roscosmos), signed a deal in which Russia becomes a full partner, contributing two heavy-lift Proton launch vehicles and an additional entry, descent and landing system for the rover mission in 2018. Under the agreement, Roscosmos was granted three asking conditions:

1. Roscosmos will contribute two Proton launch vehicles as payment for the partnership.
2. The Trace Gas Orbiter shall carry two Russian instruments that were originally developed for Fobos-Grunt.
3. All scientific results must be intellectual property of the European Space Agency and the Russian Academy of Sciences (eg: Roscosmos will have full access to research data.)

While the 2016 segment appears secure, the financial situation of the 2018 mission remains unclear. Russia's financing of ExoMars could be partially covered by insurance payments of 1.2 billion rubles ($40.7 million USD) for the loss of Fobos-Grunt, and reassigning funds for a possible coordination between the Mars-NET and ExoMars projects. On 25 January 2013, Roskosmos fully funded the development of the scientific instruments to be flown on the first launch, the Trace Gas Orbiter (TGO).

ESA had originally cost-capped the ExoMars projects at €1 billion, (USD 1.3 billion) but the withdrawal of the U.S. space agency (NASA) and the consequent reorganisation of the ventures will probably add several hundred million euros to the sum so far raised. So on March 2012, member states instructed the agency's executive to look at how this shortfall could be made up. One possibility is that other science activities within ESA may have to step back to make ExoMars a priority. On September 2012 it was announced that new ESA members, Poland and Romania will be contributing up to €70 million to the ExoMars program.

ESA has not ruled out a possible partial return of NASA to the 2018 portion of ExoMars, albeit in a relatively minor role.

Mission objectives

The scientific objectives, in order of priority, are:

• to search for possible biosignatures of Martian life, past or present.
• to characterise the water and geochemical distribution as a function of depth in the shallow subsurface.
• to study the surface environment and identify hazards to future manned missions to Mars.
• to investigate the planet's subsurface and deep interior to better understand the evolution and habitability of Mars.
• achieve incremental steps ultimately culminating in a sample return flight.

The technological objectives to develop are:

• landing of large payloads on Mars.
• to exploit solar electric power on the surface of Mars.
• to access the subsurface with a drill able to collect samples down to a depth of 2 metres (6.6 ft)
• to develop surface exploration capability using a rover.

Launch vehicles

The launcher for both missions is the heavy-lift Proton,< which is a four-stage rocket that was previously used to launch the Salyut 6, Salyut 7, Mir and some International Space Station components.

Mission architecture

ExoMars is a two-mission project that is considered as a single program at ESA. According to current plans, the ExoMars project will comprise four spacecraft: two stationary landers, one orbiter and one rover. All mission elements will be sent in two launches.

Contributing agency	First launch in 2016	Second launch in 2018
	Proton rocket	Proton rocket
	Most instruments for the TGO.	Russian landing system & some rover instruments
	Trace Gas Orbiter	ExoMars rover
	EDM lander

First launch - 2016

Trace Gas Orbiter

The Trace Gas Orbiter.

Main article: ExoMars Trace Gas Orbiter

The Trace Gas Orbiter (TGO) will be a Mars telecommunications orbiter and atmospheric gas analyzer mission for launch on January 2016. It will deliver the ExoMars EDM lander and then proceed to map the sources of methane on Mars and other gases, and in doing so, help select the landing site for the ExoMars rover to be launched on 2018. The presence of methane in Mars' atmosphere is intriguing because its likely origin is either present-day life or geological activity. Upon the arrival of the rover in 2018/2019, the orbiter would be transferred into a lower orbit where it would be able to perform analytical science activities as well as provide the EDM lander and ExoMars rover with telecommunication relay. NASA will provide an Electra telecommunications relay and navigation instrument to assure communications between probes and rovers on the surface of Mars and controllers on Earth. The TGO would continue serving as a telecommunication relay satellite for future landed missions until 2022.

EDM lander

The Entry, Descent and Landing Demonstrator Module (EDM) will provide ESA with the technology for landing on the surface of Mars with a controlled landing orientation and touchdown velocity; key technologies for the 2018 mission. After entering the Martian atmosphere, the module will deploy a parachute and will complete its landing by using a closed-loop guidance, navigation and control system based on a Radar Doppler Altimeter sensor and on-board Inertial Measurement Units. The latter will guide a liquid propulsion system which will produce a semi-soft touchdown on the surface of Mars by the actuation of clusters of thrusters to be operated in pulsed on-off mode.

Its proposed landing site is the Meridiani Planum because it is almost flat and without too many rocks, ideal for its airbag landing system.

The landing will take place during the dust storm season, this will provide a unique chance to characterise a dust-loaded atmosphere during entry and descent, and to conduct surface measurements associated with a dust-rich environment. Once on the surface, it will measure the wind speed and direction, humidity, pressure and surface temperature, and determine the transparency of the atmosphere. It will also make the first measurements of electrical fields at the planet's surface. A color camera system is included in the payload.

At first, the Russians offered to contribute a 100 watt radioisotope thermoelectric generator (RTG) power source for the EDM lander to allow it to monitor the local surface environment for a full Martian year, but the Russians finally opted for the use of a regular electric battery with enough power for four Martian days.

EDM surface payload

The ExoMars 'Entry, Descent and Landing Demonstrator Module' (EDM) is a stationary lander originally planned to carry a group of eleven instruments collectively called the "Humboldt payload", that would be dedicated to investigate the geophysics of the deep interior. But a payload confirmation review in the first quarter of 2009 resulted in a severe descope of the lander instruments, and the Humboldt suite was cancelled entirely.

The latest EDM surface payload, based on the proposed meteorological DREAMS (Dust Characterisation, Risk Assessment, and Environment Analyser on the Martian Surface) package, consists of a suite of sensors to measure the wind speed and direction (MetWind), humidity (MetHumi), pressure (MetBaro), surface temperature (MarsTem), the transparency of the atmosphere (Optical Depth Sensor; ODS), and atmospheric electrification (Atmospheric Radiation and Electricity Sensor; MicroARES).

The DREAMS payload will function as an environmental station for the duration of the EDM surface mission after landing. DREAMS will provide the first measurements of electric fields on the surface of Mars (with MicroARES). Combined with measurements (from ODS) of the concentration of atmospheric dust, DREAMS will provide new insights into the role of electric forces on dust lifting, the mechanism that initiates dust storms. In addition, the MetHumi sensor will complement MicroARES measurements with critical data about humidity; this will enable scientists understand better the dust electrification process.

In addition to the surface payload, a colour camera system on the EDM will deliver additional scientific data in the form of images. No design has yet been chosen for the camera.

Second launch - 2018

Russian landing system

The second mission, scheduled for launch in 2018, will have a 1800 kg Russian landing system place the ExoMars rover on the surface of Mars. This lander module will be built 80% by Russia and 20% by ESA. The Russians will produce most of the landing system's hardware, while ESA will handle elements such as the guidance and navigation systems. Critics have stated that while Russian expertise may be sufficient to provide a launch vehicle, it does not currently extend to the critical requirement of a landing system for Mars.

Proposed landing sites

Mawrth Vallis with its potential clues on the history of water on Mars is a landing site-candidate.

As of November 2007, the rover's potential landing sites are:

• Mawrth Vallis
• Nili Fossae
• Meridiani Planum
• Holden Crater
• Gale Crater

The 2009 discovery of methane sources on the planet makes them a high value target for exploration. The presence of methane is intriguing because its likely origin is either present-day life or geological activity; confirmation of either would be a major discovery. Methane occurres in extended plumes, and the profiles imply that the methane was released from discrete regions. The profiles suggest that there may be two local source regions, the first centered near 30° N, 260° W and the second near 0°, 310° W. To determine the optimal landing site and secure telecommunications, it was decided to include the Trace Gas Orbiter in the 2016 launch in order to map beforehand what appears to be seasonal methane production. The rover could then investigate the methane sources identified by the orbiter.

Rover

Main article: ExoMars rover

An early design ExoMars rover test model at the ILA 2006 in Berlin		Another early test model of the rover from the Paris Air Show 2007

The ExoMars rover is an autonomous six-wheeled terrain vehicle planned for Mars.

See also

• Astrobiology
• Biological Oxidant and Life Detection mission
• Beagle 2 lander
• Exploration of Mars
• Life on Mars
• Mars Exploration Rover - Mission with two rovers
• Mars sample return mission
• Mars Science Laboratory rover
• Viking program

External links

• Official website
• ESA main web site
• Raman-LIBS spectrometer for ExoMars Combined Raman-LIBS spectrometer for ExoMars
• EADS Astrium ExoMars rover vehicle
• The ExoMars project at RussianSpaceWeb.com
• THALES : Press Info: Exomars Status (May 8, 2012)