Pleiades NEO, the Airbus Very High Resolution constellation

Airbus will launch two pairs of optical satellites, one in 2020 and one in 2021, to form a constellation with two orbital planes enabling two revisits per day. The satellites will have a 30cm resolution, a 14km swath, and orbit at 620km altitude. They will leverage the EDRS data relay satellites for ultra-fast tasking and downlink. The constellation is called Pleiades Neo, and will image 2 million km² per day. The rest of the article details how this fully private constellation is a change compared to the previous French public-private observation satellites, and how information about the constellation has emerged since the announcement in 2016.

Pleiades Neo
A Pleiades Neo satellite

Airbus Defense & Space announced in September 2016 that it will launch a constellation of 4 Very High Resolution (VHR) optical earth observation satellites, in 2020 and 2021. This will be a follow-on to the Pléiades constellation, which comprises two agile, 70cm resolution satellites, launched in 2011 and 2012. Unlike Pléiades, which was a public-private partnership between Airbus (the prime contractor), Thales (which provided the instruments) and the French Ministry of Defense, this new constellation will be entirely financed by Airbus, to the tune of 550M€.

Picture3
Pléiades (Airbus Defense & Space, France)

According to the press release, “Pléiades system features will be improved to match the market requirements expected to be the norm at the time of launch”, which I speculated to mean the resolution will be improved to 30cm, to match the resolution of the Worldview 3 and Worldview 4 satellites owned by Airbus’  main competitor, Digital Globe. Airbus has since confirmed the 30cm resolution. This is coherent with the studies on the design of 20 to 30 cm resolution satellites carried out by CNES, the French space agency.

 

These studies led to the ARCTOS concept by Airbus, with a 30cm resolution from 700km up, a 20km swath, and a small enough mass to be launched from a Vega launcher thanks to a lightweight 1.5m SiC mirror. Resolutions higher than 30cm are much more difficult to achieve. Besides, the release calls the constellation “VHR”, which is between HR (around 70cm, like Pléiades) and EHR (extremely high resolution, around 20cm) in the French classification of resolution. Airbus is also the prime contractor for CSO,  a military EHR satellite to be launched around 2020, but this satellite fly will relatively low in order to achieve this resolution, so the technology is probably not mature for an EHR satellite at 700km altitude. CNES, Airbus and Thales are also working together on the OTOS concept, which would use adaptative optics to correct for mirror deformations.

Consequently, at the time of the announcement, I estimated the constellation would be made of four 30cm resolution satellites. Since the release states it will provide “intra-day” revisit, this means the constellation will have two orbital planes: from orbits around 700km, two agile satellites on the same orbital plane are required to provide same-day revisit, so two planes are needed.

This constellation will help Airbus catch up with Digital Globe, but the US company has already announced it is designing its next-generation constellation, which will be made up of six 1m-resolution satellites build and operated by the United Arab Emirates and a high-resolution component owned by Digital Globe. The Emirati satellites will provide a high temporal revisit, enabling to detect changes  and then cue the higher resolution satellites to characterize these changes. The former are scheduled for launch in 2018 and 2019,  around the same time Digital Globe plans to seriously invest in the latter.

Finally, the release mentions the constellation will be “dual”, which probably means it will be a dual-use civilian and military constellation, giving the French Ministry of Defense  tasking priority when required. This would considerably increase the temporal revisit capability of the French reconnaissance system.

Update 16 September 2016: Spacenews quotes an industry official saying Airbus will invest at least 550m€ in the constellation, the resolution being not set but around 40cm, and the instruments being Airbus-made SiC telescopes.

Update 26 January 2017: Peter B. de Selding reports the satellites will use the EDRS network for laser data relay, enabling near-real time access to the images.

Update 12 May 2017: Airbus will probably use CILAS deformable mirrors for its satellites, as CILAS and Airbus are collaborating on the OTOS program and the technology seems mature.

Update 16 June 2017. Airbus Defense & Space boss has confirmed the constellation will have 30cm resolution, and given its name, VHR2020.

Update 15 September 2017: Airbus has re-branded the constellation as “Pleiades Neo”, and says it will have a Ka-band receiver for instant tasking through EDRS, and confirms laser data relay through EDRS. It announces a capacity of half a million km² per day per satellite, at 30cm resolution (30cm is really the native resolution according to other sources). It has also released this photo, showing a new solar panel design compared to Pléiades:

Pleiades Neo

Two of those are to be packed in a Vega fairing at launch, with a first launch still scheduled in 2020.

Update 15 October 2017: French aerospace magazine Air & Cosmos has published a feature article on the constellation. It states the satellites will orbit at 620km altitude, weigh less than a ton each, have around 1kW of power and have two special spectral bands: a “deep blue” band for water penetration and a “red edge” band for vegetation monitoring. Their swath width will be 14km.

Since the altitude and resolution of the satellites are now known, the mirror size can be determined, and it has to be around 1.35m. That means a pair of satellite side-by-side does not fit in a 3.3m Vega C+ fairing, so they must be launched one on top of the other, maybe with a VESPA adapter, or maybe by just stacking the satellites without any adapter.

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