EntrySat (original) (raw)

EntrySat (QB50 FR02) [ISAE]

EntrySat is a French 3U-CubeSat designed by the Institut Sup�rieur de l�A�ronautique et de l�Espace�(ISAE) and ONERA participating in the QB50 project as an In-Orbit demonstrator, developed to investigate the properties of orbital debris during atmospheric entry.

The EntrySat experiment consists of inserting a nanosatellite in the form of a 3U CubeSat into low-Earth orbit (which is similar in principle to secondary debris typically issued from launch vehicles or satellites). A science module operating during the reentry phase will be able to perform in - situ measurements of the CubeSat environment as well as integrity up to its destruction. Acquired data will be sent in real time through the Iridium constellation back to the ground segment.

The first part of the experiment deals with accurate prediction of orbit al decay, especially with respect to time remaining before entry, typically a few weeks or months. At the atmospheric entry point, the slope angle suddenly increases and the object will reach the ground or be destroyed in a very short time, usually a few minutes or hours. Accuracy of the trajectory simulation during orbit decay depends on the accuracy of several physical models:

• Atmospheric modeling (between 120 and 300 km): the whole QB50 project contributes to increase knowledge of the thermosphere since this is its first goal.
• Aerodynamic coefficients modeling in the rarefied and transitional regime.

To refine these models, aerodynamic forces and associated kinematics (position, attitude motions) should be available; EntrySat will perform these measurements during orbit decay phase.

During the second part of the experiment � the destruction phase � EntrySat will melt and break up in a few minutes at a maximum. The expected velocity value is about 7 km/s and the break - up altitude and on-board conditions changes can be only determined if the CubeSat is suitably equipped to send information during re-entry. This kind of information is of primary importance to improve the multi-physics modeling during atmospheric re-entry as well as to improve the prediction of the survivability of satellite or launch vehicle elements.

The QB50 project, which demonstrates the possibility of launching a network of 50 CubeSats built by Universities Teams all over the world to perform first-class science in the largely unexplored lower thermosphere.

The satellite was originally planned to be launched with the bulk of the QB50 constellation to the ISS in 2017, from where they will be deployed. Later a launch in 2018 with ESA's "Fly Your satellite" initiative is envisioned, also with deployment from the ISS. Eventually it will be launched on the Cygnus CRS-11 cargo mission to the ISS.