RESEARCH MASTER INTERNSHIP 2016-2017

RESEARCH MASTER INTERNSHIP
2016-2017
Space Systems for Planetary Applications/DEOS
Location :
Superviser : Naomi MURDOCH
Tel. :
E-mail. :
Toulouse, France
+33 5 61 33 87 03
[email protected]
INTERNSHIP DESCRIPTION
Domains : Planetary Science, Geophysics, Mechanics, Space Systems
Title : Measuring the surface mechanical properties of an asteroid during landing
In 2014, the European Space Agency’s (ESA’s) Rosetta spacecraft became the first mission to successfully deliver
a lander to a comet’s surface. Though the Philae lander eventually came to rest, its anchoring harpoons failed to
fire upon descent, and the lander proceeded to rebound twice over a duration of approximately 2 hours before
reaching its final destination, roughly 1 km away from the intended landing site [1,2]. The understanding of
surface-lander interactions is particularly important for current and future space missions that include lander
components e.g., the MASCOT and the MINERVA rovers on-board JAXA's Hayabusa-2 mission [3], MASCOT2 and possibly AGEX on board ESA's AIM mission [4-6]. In addition, the surface – lander interactions can allow
esimates to be made of the mechanical properties of the small body surface material [1].
Here at ISAE-SUPAERO we have developed a drop tower experiment (Fig 1) in order to study the problematic of
landing on asteroids and comets in very low gravity conditions. In the experiment rig, reduced-gravity is
simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that
of Earth's gravity. The acceleration of the surface is controlled through the use of an Atwood machine, or a system
of pulleys and counterweights. Accelerometers, placed on the surface container and inside the projectile, provide
acceleration data, while high-speed cameras capture the collision and act as secondary data sources. For detailed
information about the experiment see [7].
Figure 1: Images sequence depicting the initial release, free-fall, and collision phases for a 2.0 m drop test. The
top row of images is from an AEE MagiCam SD100 camera that was mounted inside of the surface container, and
the bottom row of images is still frames from the Ultima APX-RS Photron high-speed camera. See [3] for more
details.
The goal of this research project is to study the impact dynamics during low-velocity granular collision
experiments, and to investigate how the asteroid mechanical surface properties can be determined from
accelerometer data. The student will first develop a theoretical framework for determining the surface mechanical
properties from accelerometer data. Then, laboratory experiments will be performed in 1g and in reduced-gravity
using the ISAE-SUPAERO drop-tower to put this into practice. The influence of the projectile form and the
surface material properties will also be investigated. The results will have a direct implication for the choice of
instruments and the design of future asteroid landers.
References
[1] Biele, et al., « The landing(s) of Philae and inferences about comet surface mechanical properties” Science
349, aaa9816 (2015).
[2] Ulamec, et al. « Rosetta Lander – Landing and operations on comet 67P/Churyumov–Gerasimenko » Acta
Astronaut. 125, 80 (2016).
[3] Tsuda et al., « System design of the Hayabusa 2 asteroid sample return mission to 1999 FJU3G », Acta
Astronautica 91 (2013).
[4] Michel et al., « Science case for the asteroid impact mission (AIM): A component of the asteroid impact and
deflection assessment (AIDA) mission », Advances in Space Research 57, 12, (2016).
[5] Ho et al., « A Mobile Asteroid Surface Scout for the AIDA Mission », EGU (2016).
[6] Karatekin et al., « The Asteroid Geophysical Explorer (AGEX); A proposal to explore Didymos system using
Cubesats», EGU (2016).
[7] Sunday et al., « A novel facility for reduced-gravity testing: A setup for studying low-velocity collisions into
granular surfaces » Review of Scientific Instruments 87, 084504 (2016).
10 % Theoretical Research
Possibility to go on a Ph.D.:
30 % Applied
Research
o Yes
60% Experimental Research
o No
APPLICANT PROFILE
Knowledge and required level:
The candidate must be rigorous, autonomous and enjoy lab work and data analysis.
A background in physics, mechanics or planetary science would be an advantage, as would previous experience
with Matlab and laboratory experiments.
Applications should be sent by e-mail to the supervisor.