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Proba-1 and its 18 years of successful operations

20 December 2019

Launched on 22 October 2001 and originally designed as a two-year mission, Proba-1 continues to provide valuable hyperspectral data to the scientific community, alongside priceless insight of long-lived missions—all while having travelled 4,329,416,712 kilometres to date.

The original objectives of Proba-1 (Project for On-Board Autonomy-1) were as an in-orbit demonstration and evaluation of new hardware and software for spacecraft technologies and of on-board operational autonomy.

Just a cubic metre in volume, this microsatellite is a technology demonstrator and primarily thanks to its Compact High Resolution Imaging Spectrometer (CHRIS), Proba-1 later became a dedicated Earth observation mission that has continuously acquired environmental science imagery.

CHRIS is able to record 17 to 34 metre spatial resolution data across a programmable selection of up to 63 spectral bands (see K-means clustering applied to a Proba-1 image acquired over Itatiaia, Brazil, on 13 July 2017), at five different viewing angles. Its different modes trade-off the spatial and spectral resolution, allowing it to collect targeted data for specific applications.

The sites (data acquired over specific locations for different purposes) were requested by scientists with nearly 6,855 successful acquisitions to date; with scenes spread across the world and some being acquired for the entire mission's lifetime.

CHRIS has been used in a wide range of applications from understanding the species abundance and succession of forests to mapping regional land-cover, benthic macroalgal communities and coastal marsh ecosystems, alongside water quality management. New scientific sites are being added each year with, to date in 2019, 189 science sites acquired; data requested by 64 Principal Investigators, with 418 usable acquisitions.

Some sites of interest have actually been acquired without interruption for 18 consecutive years, providing an undisputed long-term value to the mission. These sites, presented below in the images, are used for calibration and validation, and also as reference sites to various areas of applications, ranging from agriculture, to land cover and water quality.

 

Proba-1 carries thee other instruments in addition to CHRIS, each serving different applications. The High Resolution Camera (HRC) is a black and white camera with a miniature telescope, which can acquire scenes of 25 square km at 5 m spatial resolution. The Debris In-Orbit Evaluator (DEBIE-1) is designed to monitor sub-millimetre particle impacts to develop risk assessment models and designs for protective shielding. The Standard Radiation Environment Monitor (SREM) gathers data on space weather around the satellite.

ESA offer data products from the CHRIS and HRC instruments, which are available to download following a fast registration procedure. Learn more about the CHRIS and HRC data products, and how to apply for them.

The DEBIE-1 and SREM instruments are also still fully functioning and data are available on dedicated servers. The Proba-1/SREM data are available from the SREM PSI site, providing the full set of data from the SREM instruments also from the INTEGRAL, Herschel, Planck and Rosetta missions. 

The German company etamax space is still working on the data processing, storage and analysis of the DEBIE-1 instrument, under ESA contract. The scientific data acquired by the instrument is considered an important contribution to the validation of space debris and micro-meteoroid environment models, such as ESA's MASTER model.

Therefore, the science communities are highly interested in a continuation of the SREM and DEBIE data acquisition and the subsequent results.

Proba-1 Mission Manager, Giuseppe Ottavianelli, states, "From space debris and radiation environment monitoring, to hyperspectral imaging, Proba-1 is providing both long-term measurements extremely valuable to a wide spectrum of science and also new acquisitions tailored to develop and test innovative EO applications. We keep an active dialogue with our users and in 2019 we added 23 new areas of interest for the CHRIS instrument, responding to recent R&D requests.

"With potentially another 15 years of operations given the current de-orbit analysis, the platform is also performing very well despite the 18 years of operations. This has also sparkled an interest in external partners on the technical performance of various subsystems. For instance, we are discussing the battery performance degradation profiles with Jet Propulsion Laboratory (JPL) Power and Sensor Systems Section.

"Overall, I consider Proba-1 to be a true explorer in various fields and has been demonstrating, since 2001, the capacity of on-board autonomy, almost a Phi-sat precursor! I thank the entire operations team supporting the mission, and the scientists involved in the exciting science and application topics," concluded Ottavianelli.