Comet Interceptor will be the successor of Giotto (first flyby of Comet 1P/ Halley) and Rosetta mission (first landing on a comet 67P/ Churyumov-Gerasimenko better known as Chury).

This time, it will be the first mission ever to fly-by in formation around a pristine comet or interstellar object such as Oumuamua.

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So, the purpose is to realize the first fly-by in formation around a comet. Therefore, 3 distinct spacecrafts, solar powered, will be part of this mission. The primary platform will carry at the beginning of the journey the 2 secondary spacecrafts. They will separate few days or few weeks before the interception. The main one, the primary platform, will be used as communication hub in addition to the observation.  The three spacecrafts will be equipped with different science payloads in order to provide huge range of observation (gas, dust, nucleus, and plasma environment of the comet). Therefore, this kind of fly-by will be interesting for imaging and scientific study concerning the origin of the Solar System and the evolution of the comet and interstellar object. Also, thanks to the fly in formation, a 3D profile of the comet will be established to appreciate the dynamic nature of the object.

 

It will be the first mission to be launched to an unknown object up to now. Indeed, the probe will reach for its first step the Sun-Earth Lagrange Point L2 (1.5 million kilometers from the Earth) then it will wait there until the approach of an interstellar object (or pristine comet). At this moment the probe will be reactivated in order to meet the interstellar body (pristine comet or interstellar object). This is the particularity of this mission, to meet an object which will enter into the solar system for the first time. It will be probably a comet coming from the Oort cloud (around the solar system). Therefore, the comet will be virgin of degradation and it will be composed of raw material from the dawn of the solar system.

 

The interest to launch a mission prior to know the final objective is due to the difficulty to predict new comets or interstellar objects which will pass in our solar system. The unknown comets or interstellar objects are discovered only few months before they closest approach to the sun, where the elements of the comet will be degraded. After its first passage near the sun, the object in question has lost an important part of its pristine characteristics, so too late to observe raw materials. Moreover, it is impossible to develop a mission and launch a spacecraft in this very short time frame. So, here is the interest to prepare all the mission, launch it, and wait the arrival of the object to intercept it.

 

This mission is fast-class mission directed by ESA and it is part of the Cosmic Vision Programme. That’s mean that this mission is based on heritage and without specifics and complicated development. For example, the camera for comet interceptor will be based on the camera uses on the ExoMars mission, scientific equipment such as a spectrometer, plasma instrument will be inspired from the Rosetta mission. In that way, the beginning of the mission until the launch time shall not exceed 10 years. Also, the mass of the probe is reduced at its maximum (below 1000 kg) in order to be launched in the same rocket of a Medium-class mission (with Ariel spacecraft in 2028 in this case).

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