February 12, 2020

Ground Based Assets

The American and Russian operational surveillance systems are presented in brief. Many countries have ground-based means and some have orbital resources. The list is lengthy, so this page will only present the French resources, in particular those of CNES.

There are at present several operational surveillance systems:

1.- The American surveillance network, consisting of radars and telescopes, which is operated by 18th Space Control Squadron (18 SPCS), regularly tracks about 20,000 objects larger than 10 cm in low orbit and larger than 1 m in high orbit. It keeps an up-to-date catalogue of objects. The public version of this catalogue is available from www.space-track.com.
2.- The Russian surveillance network also uses radars and telescopes. It is operated by the National Air Defence force (PVO) with the participation of four other operational organisations (IKI INASI, Space Research Centre Kosmos, Vympel Corporation, Kias System). This system keeps an up-to-date catalogue of objects. No public version of this catalogue is available on the web.

3.- The French GRAVES military system, developed by ONERA, is operated by the CDAOA  (Air Defence and Air Operations Command). It can track about 2,000 objects in low earth orbit.

The main missions of an operational surveillance system are to detect, identify and track objects, to process the measurements taken by the sensors, to create and update a catalogue of objects, to schedule the tasks of the sensors and to predict atmospheric re-entry by the objects.

France has both military and civil radars and telescopes


The GRAVES radar was deployed by the French Air Force in 2005. It is dedicated to monitoring and tracking objects in low orbit.

The SATAM tracking radars are operated by the French Air Force and their main role is to track debris for management of collision risks and to predict atmospheric re-entry.

The BEM Monge tracking ship is deployed by the French navy but the radar equipment installed on it belongs to DGA/DCE. It has 3 tracking radars.

BEM Monge Tracking Ship Credits: French Navy


CNES uses TAROT system, which consists of three equatorial mount Newtonian type telescopes, equipped with CCD cameras. The TAROT system belongs to CNRS. One of the TAROT telescopes is installed on the Calern plateau in France, another in the Silla observatory in Chile, and the third one in Reunion Island. The field of view of the TAROT telescopes is 1.86° x 1.86° for the telescopes in Calern and Chile, and 4.2° x 4.2° for the one in Reunion Island. The main role of these telescopes is to observe the counterparts of gamma-ray bursts, a phenomenon which occurs about once every 15 days on average. CNES thus uses TAROT the remaining available time for observation of space debris. During this observation time, TAROT can be used to detect and monitor objects in geostationary or geosynchronous orbit and has enabled to build up a catalogue of objects in geostationary orbit which is daily maintained. TAROT is also regularly used for “IADC exercises”.

TAROT Telescope Credits: INSU, CNRS