Orbital AIM User Manual

Mission description, Noctilucent clouds, Facts at a glance

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Heliophysics

Mission Description

The Aeronomy of Ice in the Mesosphere (AIM) mission is focused on the study of Polar Mesospheric
Clouds (PMCs) that form about 50 miles above the Earth’s surface in the summer months, primarily
in the polar regions. The AIM observatory will measure PMCs and the thermal, chemical and dynamic
environment in which they form in order to determine the connection between PMCs and the
meteorology of the polar mesosphere. This connection is valuable because the increased appearance
of noctilucent, or night shining clouds (NLCs), which are a manifestation of PMCs, has been suggested
as an indicator of global climate change. Through these measurements the team will address questions
including:

• Why do noctilucent clouds form and vary?

• Why have noctilucent clouds been occurring closer to the equator?

• Why have noctilucent clouds been getting brighter and denser?

• Are noctilucent clouds nature’s harbinger of global change in the upper atmosphere?

Orbital Sciences Corporation, under contract to a university team led by Hampton University, provided
the AIM spacecraft bus, instrument integration, satellite environmental test campaign and launch
operations.

Noctilucent Clouds

First sighted in 1885 in Northern high latitudes, noctilucent, or night shining clouds occur in the summer
in the mesosphere, which is the coldest part of the atmosphere. Cloud formation is possibly hastened
by increasing amounts of carbon dioxide in the atmosphere. While CO2 is thought to contribute to
global warming on Earth, it actually cools the high atmosphere. In recent years, noctilucent clouds have
begun appearing closer to the equator.

Noctilucent or "night-shining" clouds
were first seen in 1885 about two years
after the powerful eruption of Krakatoa
in Indonesia, which hurled plumes of
ash high into Earth's atmosphere.

Crews aboard the International Space
Station routinely witness noctilucent
clouds when flying over Australia and
the tip of South America.

Mission:

NASA Small Explorers (SMEX) program

Customer:

Hampton University

University of Colorado at Boulder, LASP

FACTS AT A GLANCE

AIM

Aeronomy of Ice in the Mesosphere

LEO

AIM in Orbital’s Dulles, Virginia satellite
manufacturing facility

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