TANGO (Twin Anthropogenic Greenhouse Gas Observers)

Quick facts

Overview

Summary

Mission Capabilities

Each TANGO CubeSat will carry one of two Spectrolite imagers, developed by TNO. The imagers build on existing instrument heritage of the TROPOMI instrument, carried on the Sentinel-5 Precursor mission. The instruments are all-aluminium pushbroom hyperspectral imaging spectrometers, and have achieved a lower mass and volume profile due to the use of free form optics in the spectrometer design. The instruments are capable of measuring CO2 and CH4 emissions and atmospheric concentrations, as well as Nitrogen Oxide (NOx) compounds, enabling the determination of historic CO2 emissions trends.

Performance Specifications

The selected Spectrolite instruments will both have a spatial resolution of 300 m x 300 m, operating in the Visible spectral range, 405 nm - 490 nm. The instruments will be capable of measuring CO2 with a threshold of greater than 5 Mt/year and measuring CH4 with a threshold of greater than 10 kt/year.

Space and Hardware Components

The TANGO CubeSats will both use a 12U form factor CubeSat platform, manufactured by ISISpace.
 

Overview

The Twin Anthropogenic Greenhouse Gas Observers (TANGO) mission consists of two CubeSats, aiming to monitor methane (CH4) and carbon dioxide (CO2) emissions. The mission concept has been designed by a consortium of Innovative Solutions in Space (ISISpace), the Netherlands Institute for Space Research (SRON), the Royal Netherlands Meteorological Institute (KNMI) and the Netherlands Organisation for Applied Scientific Research (TNO). TANGO will allow greenhouse gas monitoring at the level of individual power plants and industrial facilities, as well as complementing the existing ESA Copernicus global survey missions, such as Sentinel-5P and CO2M. TANGO has been proposed as an ESA Scout mission to the Advisory Committee for Earth Observation (ACEO).

TANGO aims to quantify and verify emissions observations with unprecedented emission flux precision, and its use of tandem CubeSats increases the number of detectable targets. The TANGO CubeSats are designated TANGO Nitro, which aims to improve detection of NO2 plumes and measurement of atmospheric CO2/NO2 ratios, and TANGO Carbon, which aims to quantify CO2 and methane emissions. Additionally, due to the use of a CubeSat platform, the mission will have the potential to expand into a larger scale constellation for more global coverage. The mission aims to have an open data policy with a wide data user community. 2) 3) 4) 8) 9) 13) 17)

Spacecraft

The TANGO satellites will each utilise an identical CubeSat bus, with a 12U form factor. These CubeSat buses have been manufactured as part of the ISISpace Assembly Integration Verification and Testing (AIVT) process. The platform is a high agility CubeSat, enabling in-orbit pointing. 8) 12)

Launch

The TANGO CubeSats are planned for launch in 2024.

Mission Status

• 7 October, 2020: The mission concept for the TANGO program was presented to the Advisory Committee for Earth Observation (ACEO). 14)
• 10 July, 2020: The consortium of ISISpace, TNO, SRON and KNMI received a mission study contract from the European Space Agency (ESA) for the TANGO mission. 7)
• 13 October, 2017: The TROPOMI instrument, the predecessor to the Spectrolite family of instruments, was launched into orbit as part of the Sentinel-5 Precursor mission. 16)

Sensor Complement

TANGO will use two Spectrolite imagers based on technology used in the TROPOMI instrument, carried by each CubeSat. These instruments are all-aluminium pushbroom hyperspectral imaging spectrometers, developed by TNO, and will enable observation of CO2 (Carbon Dioxide), CH4 (Methane) and NOx (Nitrogen Oxide Compounds) emissions and atmospheric concentrations at the scale of individual industrial sites. The instruments will have a spatial resolution of 300 m x 300 m, and operate in the VIS (Visible) spectral range, of 405 nm - 490 nm. The instruments have achieved a low mass and volume profile due to the application of free form optics, wherein the optical component of the instrument has no axis of rotational invariance, allowing greater correction of multiple aberrations with fewer optical surfaces, as shown in Figure 1. This has allowed an instrument mass of < 10 kg, and the application of the instruments in the TANGO CubeSat missions. 5) 6) 10) 13)

The TANGO Spectrolite instruments will be capable of measuring CO2 with a threshold of > 5 Mt/year and a goal of > 2.5 Mt/year, and CH4 with a threshold of > 10 kt/year and a goal of > 5 kt/year. The instruments will also be able to measure NOx emissions, improving the detection of CO2 plumes and deriving historic CO2 emissions trends based on available global NOx data, as well as differentiating the contribution of CO2 in mixed CH4 - CO2 plumes. Due to the high agility nature of the selected CubeSat platform, the TANGO CubeSats are able to utilise a stare method, continually adjusting their pointing direction along each pass to focus on a single area. 1) 8) 11) 16)

References

1) Caron, J. F., and S. M.B Baumer. “Progress in freeform mirror design for space applications.” TNO, URL: https://repository.tno.nl/islandora/object/uuid%3A81b79436-ef0d-4c21-8f3f-b69cad99bbf7

2) Court, A. J., and J. L. Bezy. “Compact hyperspectral instrument for NO2 remote sensing.” TNO, URL: https://repository.tno.nl/islandora/object/uuid%3A7fb112e3-683e-49df-a287-e00534103ec3

3) Court, A. J., and B. T.G de Goeji. “Developments by TNO for small atmospheric chemistry space instruments: Current status and future prospects | TNO Publications.” TU Delft Repositories, URL: https://repository.tno.nl/islandora/object/uuid%3A4d0eaadc-e607-4f19-850d-dd8e0f291154

4) “Earth observation: monitoring our planet.” TNO, URL: https://www.tno.nl/en/sustainable/space-scientific-instrumentation/earth-observation-monitoring-our-planet/

5) “Freeform Optics.” Shanghai Optics, URL: https://www.shanghai-optics.com/components/freeform-optics/

6) “Freeform Optics for Imaging.” Optica, URL: https://doi.org/10.1364/OPTICA.413762

7) “ISISPACE-led consortium aims to implement novel small satellite system for emission detection in TANGO project.” ISISPACE, 10 July 2020, URL: https://www.isispace.nl/news/isispace-led-consortium-aims-to-implement-novel-small-satellite-system-for-emission-detection-in-tango-project/

8) Kulu, Erik. “TANGO.” Nanosats Database, 9 June 2023, URL: https://www.nanosats.eu/sat/tango

9) “Potential benefits of free-form optics in on-axis imaging applications with high aspect ratio.” Optica, URL: https://opg.optica.org/oe/fulltext.cfm?uri=oe-21-25-31072&id=275923

10) Snijders, B., and L. F. van der Wal. “Compact spectrometers for earth observation | TNO Publications.” TU Delft Repositories, URL: https://repository.tno.nl/islandora/object/uuid%3A749374fa-2047-4b0e-a0ac-36b028d9ad7e

11) “TANGO.” SRON, URL: https://www.sron.nl/missions-earth/tango

12) “TANGO.” ISISPACE, URL: https://www.isispace.nl/projects/tango/ 

13) “The TANGO mission: A satellite tandem to measure major sources of anthropogenic greenhouse gas emissions.” NASA/ADS, URL: https://ui.adsabs.harvard.edu/abs/2020EGUGA..2219643L/abstract

14) “TANGO mission project presentation.” ISISPACE, 7 October 2020, URL: https://www.isispace.nl/news/tango-mission-project-presentation/

15) “TANGO satellite: monitoring greenhouse gas emissions.” TNO, URL: https://www.tno.nl/en/sustainable/space-scientific-instrumentation/earth-observation-monitoring-our-planet/tango-satellite-monitoring-greenhouse/

16) “TROPOMI satellite instrument.” TNO, URL: https://www.tno.nl/en/sustainable/space-scientific-instrumentation/earth-observation-monitoring-our-planet/tropomi/

17) “VN-rapport: Methaanreductie een van de meest kosteneffectieve maatregelen tegen opwarming.” SRON, URL: https://www.sron.nl/news/5148-vn-rapport-methaanreductie-een-van-de-meest-kosteneffectieve-maatregelen-tegen-opwarming

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (eoportal@symbios.space).