Skip to Content
HomeMissionBallooncraftScienceNews & Galleries


Scientific Questions BOPPS Will Address:

  • How does the composition of Oort Cloud comets compare to Kuiper Belt comets?
  • What are the chemical processes that lead to complex organic molecules in regions of star and planet formation?
  • Were there systematic chemical or isotopic gradients in early solar nebula?
  • How did Earth get its water and other volatiles?

BOPPS’s Scientific Objectives:

  • Develop and demonstrate gondola and payload systems for a balloon-borne platform designed to achieve planetary science objectives.
  • Observe comets Siding Spring and PanSTARRS in the near-infrared, near ultra-violet and visible wavelength ranges.
  • Through these observations, measure CO2 and H2O emissions and the ratio of CO2/H2O.
  • These measurements will be used as vital diagnostics of the comets’ origins and evolution.

Oort Cloud and Kuiper Belt

The Oort Cloud and the Kuiper Belt are the two most distant regions of the Solar System – most distant, that is, from the Sun. These regions contain icy bodies, which include a number of dwarf planets, and comets. The Sun, its familiar eight planets, and the Kuiper Belt are all found in the small white dot shown at the center of the quasi-spherical Oort Cloud. As we zoom in following the yellow arrow, we see the Kuiper Belt, the donut-shaped, flattened disk-like population that is found outside the orbit of Neptune. Two orbits of Kuiper Belt Objects are sketched, in red and white. Zooming in further, we see the inner solar system and the orbits of the terrestrial planets, Mercury, Venus, Earth, and Mars. We see that the Oort Cloud has an inner disk-like extension that connects to the Kuiper belt.

Comets and the Oort Cloud

Comets are icy, primitive bodies which formed in the outer solar system and which preserve chemical and mineral information on the materials and physical conditions that prevailed as the solar system formed. The composition of comets is important to understanding the processes which led to condensation and evolution of primitive materials so as to form small bodies like comets and asteroids and eventually to make planets. The volatile species in cometary ices, especially water, carbon dioxide and organic molecules, are of special importance for understanding how these species, which are critical to the evolution of life, were distributed and transported throughout the early solar system.

Comets are stored in two principal reservoirs in our solar system – the Kuiper Belt beyond Neptune (30 AU to 60 AU from the Sun) and the much more distant Oort Cloud (approximately 5,000 to 100,000 AU from the Sun). Most of the comets which are seen from Earth or which have been encountered by spacecraft so far have come from the Kuiper Belt after they evolved into elliptical orbits that enter the inner solar system. BOPPS will study two comets that come from the Oort Cloud, and these provide precious opportunities to study objects that have never been heated by coming close to the Sun. Oort Cloud comets may have formed from different materials and under different conditions than Kuiper Belt comets.

Measuring compositions of Oort Cloud comets, versus ecliptic Kuiper Belt comets, will help us to understand cometary origins and the dynamical evolution of the early solar system. In addition, comets in the Oort Cloud may include material and objects captured from neighboring solar systems in the Sun’s birth cluster. This means that compositional studies of Oort Cloud comets, when they visit the inner solar system, provide important opportunities to address where and how these comets formed, whether compositional signatures of interstellar materials are preserved, how their birth conditions and histories may differ from those of Kuiper Belt comets, and what materials, including water and organics, were delivered to the early Earth.

During an especially violent period in the early history of the solar system, about 4 billion years ago, the Earth and the Moon were heavily bombarded by asteroids and comets. This bombardment left on the Moon enormous impact scars and surface features (making up the “Man in the Moon”) – but on Earth, this bombardment by watery asteroids and comets may have brought in much of the water now found in Earth’s oceans.

Click to visit the NASA web site. Click to visit the APL web site.

Editor: JHU/APL Webmaster
JHU/APL Official: Mrs. A. Matiella Novak
+ Contact JHU/APL