Operating in orbit Orbiter 2016

ExoMars Trace Gas Orbiter (TGO)

ExoMars Trace Gas Orbiter (TGO), launched in March 2016 by ESA and Roscosmos, is an orbital mission dedicated to studying the Martian atmosphere and searching for trace gases such as methane. Following a long aerobraking process, it began its scientific phase in April 2018 and remains operational, combining atmospheric research with its work as a communications relay.

Agency ESA
Launch SOL 3 OF HESPERO OF YEAR 33 · 04:56 MTC
Arrival at Mars SOL 30 OF MANGALO OF YEAR 33 · 14:02 MTC
Operations Start SOL 25 OF ISIDO OF YEAR 34 · 07:02 MTC
of travel 219 days · ~213 sols
of operations so far 3,047 sols · 3,131 days
Cruise to Mars219 days
Arrival & commissioning529 days
Operating now3,131 days

Trajectory to Mars

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Technical Analysis of the ExoMars Trace Gas Orbiter (TGO) Mission

  • Mission Designation: ExoMars Trace Gas Orbiter (TGO or ExoMars Orbiter)
  • COSPAR Designation: 2016-017A
  • Operating Agency: ESA / Roscosmos (with contributions from NASA)
  • Launch Date: March 14, 2016, 09:31 UTC
  • Launch Vehicle: Proton-M/Briz-M rocket
  • Launch Site: Baikonur Cosmodrome (Pad 200/39)
    • Orbital Insertion Date: October 19, 2016, 15:24 UTC
  • Mission Status: Operational Orbit

    • 1. Historical Context and Detailed Objectives

    The scientific void that the ExoMars Trace Gas Orbiter mission aimed to fill encompassed the precise characterization of the chemical composition of the Martian atmosphere, with special emphasis on the detection and quantification of methane and other trace gases that could constitute indications of biological or geological activity. Primary objectives focused on:

    Scientific:

    • Detect and accurately map the presence of methane and other trace gases in the Martian atmosphere.
    • Study the seasonal dynamics of water vapor and the products of its photolysis.
    • Characterize the spatial and vertical distribution of minor atmospheric components and aerosols.
    • Map the distribution of hydrogen-rich deposits in the shallow subsurface.

    Engineering:

    • Validate areocentric orbit insertion and aerobraking maneuvers in the Martian atmosphere.
    • Act as a critical UHF data relay satellite for surface missions.
    • Demonstrate high-speed interplanetary telecommunications capability using X-band systems.

    2. Vehicle Architecture and Main Subsystems

    The orbiter architecture comprises a main body with dimensions of 3.5 x 2 x 2 meters and a total launch mass of 4332 kg, of which 3732 kg corresponded to the orbiter (including 112 kg of scientific payload) and 577 kg to the Schiaparelli landing demonstrator module. The solar panels deploy a span of 17.5 meters from tip to tip, generating approximately 2000 W of electrical power, complemented by two lithium-ion batteries with a total capacity of approximately 5100 Wh. The communications subsystem includes a 2.2-meter diameter high-gain antenna operating in X-band, three low-gain antennas, and Electra UHF transceivers provided by NASA for communication with surface vehicles located on Mars.

    3. Payload and Scientific Instrumentation

    The scientific payload of the orbiter is composed of four main instruments:

    • ACS (Atmospheric Chemistry Suite): Set of three infrared spectrometers intended for the detailed study of the chemistry and vertical structure of the Martian atmosphere.
    • CaSSIS (Colour and Stereo Surface Imaging System): High-resolution camera system for obtaining nadir color and stereo images, characterizing the geological and morphological processes of the surface.
    • FREND (Fine Resolution Epithermal Neutron Detector): Epithermal neutron detector focused on mapping hydrogen distribution in the shallow subsurface down to a depth of one meter.
    • NOMAD (Nadir and Occultation for MArs Discovery): High-resolution spectrometer operating in the ultraviolet, visible, and infrared ranges for the systematic detection and quantification of atmospheric trace gases.

    4. Chronology and Mission Phases

    The mission lifted off on March 14, 2016, aboard a Proton-M/Briz-M launcher. After a seven-month interplanetary cruise, the probe arrived at Mars on October 19, 2016, successfully executing orbital insertion and proceeding with the separation of the Schiaparelli module. Subsequently, the spacecraft underwent a complex aerobraking phase between March 2017 and March 2018 to adjust its final working orbit. The formal scientific phase began in April 2018 in a circular areocentric orbit at an altitude of 400 km and an inclination of 74 degrees, later entering its extended mission phase as an orbital asset and telecommunications relay.

    5. Results and Discoveries

    Among the most prominent results are the detailed mapping of the global distribution of water vapor and atmospheric deuterium, the exhaustive characterization of dust dynamics and global storms, as well as the acquisition of high-precision atmospheric density and thermal profiles. Likewise, the FREND detector has made it possible to accurately quantify hydrogen and water-rich deposits in the subsurface, while spectroscopic observations have provided ultra-precise limits on methane concentration, narrowing its scarcity compared to previous detections reported from the surface.

    6. Legacy and Importance

    The legacy of the ExoMars Trace Gas Orbiter mission lies in having established a new standard of precision in Martian atmospheric remote sensing and in having guaranteed data connectivity through its UHF relay infrastructure. Its ability to continuously monitor geochemical and atmospheric cycles solidifies its role as a fundamental node in the international robotic exploration of the red planet.

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