YoungStar

Gas Dust

0-50 m/s

Protoplanetmodel

ICAPSGas 0-50 m/s

Dust 0-50 m/s

• How do planets form?

Protoplanetarynebula

observation

model

ICAPS

• How do particles agglomerate?

Planets form in dense dust disks around new-born stars. When the protoplanets are still very little (smaller than about 1 km in size), dust agglomeration (sticking collisions) is believed to be the key process for planetary growth.

ICAPS will investigate the formation and evolution of small dust grains and agglo-merates under a variety of conditions.

• What is regolith?The surfaces of asteroids are covered by “regolith”, or layers of loosely connected and fluffy fragmentary debris, produced (in particular) by impacts with other asteroids. Planetary and satellite surfaces are also covered by regolith.

• How does its surface change with time?The formation and evolution of regolith depends on the asteroid’s gravitational field and on the mechanical properties of its constituent particles. ICAPS will simulate such regolith by forming thick and fluffy dust layers (“dust cakes”) in microgravity.

or

Measurements• light scattering • tensile strength• thermal conductivity• compressibility and influence of porosity• collisions by solid impactors and aggregates

• Why is light scattering important in astronomy?

• What can we learn about comets from light scattering?Active comets, with their bright comaeand elongated tails, have different light scattering properties. In the microgravity environment of the ISS, ICAPS will study the light-scattering properties of dust aggregatesand icy particles, under a varietyof cometaryconditions.

Dust is everywhere in our universe, both far away in the empty regions of space between the stars, and in our own solar system, in comets and on the surfaces of asteroids and planets. These tiny dust particles scatter stellar and solar light, and by studying the properties of this scattered light, astronomers establish

the physical properties of the dust, in environments that are impossible for humans to visit.

lightsource

camera

Credit: A. Dimai and D. Ghirardo, (Col Druscie Obs.), AAC

Credit: DIRBE Team, COBE, NASA

Credit:

NA

SA

in COSMICCOSMIC particle