Following Thursday's successful launch, NASA's Ionospheric Connection Explorer (ICON) is orbiting for a unique mission to investigate a region of space where changes are disrupting satellite communications and orbits can increase the radiation risk for astronauts.
A Northrop Grumman Stargazer L-1011 aircraft launched at 20:31 EDT from the Cape Canaveral Air Force Station in Florida with ICON on a Northrop Grumman Pegasus XL rocket to reach an altitude of about 39,000 feet. The first launch at 9:30 was dropped due to communication issues between the ground crew at Cape Canaveral and the plane. At the second attempt, the flight crew released their payload at 21:59. Using EDT and automated systems on the Pegasus rocket, ICON, a spacecraft about the size of a refrigerator, was brought into space.
The solar modules of the spacecraft have been used successfully, indicating that all systems are powered. After about a month of commissioning, ICON will return its first scientific data in November.
ICON will study changes in an upper atmosphere region called the ionosphere. The space weather in the ionosphere can not only disturb the communication signals, but also prematurely decompose the orbits of spacecraft and expose astronauts to radiation-related health risks. In the past, this critical region of near-Earth space was difficult to observe. Spacecraft can not fly through the deep parts of the ionosphere and balloons can not fly high enough.
"ICON has an important job to do – to help us understand the dynamic space environment near our home," said Nicola Fox. Director of Heliophysics at NASA headquarters in Washington. "ICON will be the first mission to simultaneously track what is going on in the Earth's upper atmosphere and in space to see how they interact and what changes can disrupt our communication systems."
ICON investigates the connections between the neutral atmosphere and the electrically charged ionosphere with four instruments. Three of the instruments are based on one of the most spectacular phenomena of the upper atmosphere: the so-called airglow bands.
Airglow is generated through a similar process in which the aurora gas is excited by solar radiation and emits light. Although the Northern Lights are usually limited to the extreme northern and southern latitudes, global warming is constantly occurring and much weaker. However, it is still bright enough for ICON instruments to give an idea of the density, composition and structure of the ionosphere. With the help of Airglow, ICON can observe how particles move throughout the upper atmosphere.
ICON's fourth instrument allows direct measurements of the ionosphere in the environment. This instrument characterizes the charged gases that directly surround the spaceship.
"We've put as much capacity into these satellites as may fit on the payload deck," said Thomas Immel, principal investigator for ICON at the University of California at Berkeley. "All of these instruments are focused on the ionosphere in a whole new scientific mission that is beginning now."
The orbit of the ICON around the Earth brings it to a 27 degree incline and a height of about 360 miles. From there it can observe the ionosphere around the equator. ICON will direct its instruments so that they can take a look at what is happening at the lowest limit of space, from about 90 km to 360 km above the surface. This fast orbit orbits the earth in 97 minutes as it moves around the equator, allowing ICON to scan a wide range of latitude, longitude, and local times.
ICON is an Explorer class mission. NASA's Goddard Space Flight Center in Greenbelt, Maryland manages NASA's Science Mission Directorate Explorer program in Washington. The University of California at Berkeley has developed the ICON mission and the two ultraviolet spectrographs Extreme Ultra-Violet and Far Ultra-Violet. The Washington Naval Research Laboratory developed the Michelson Interferometer for a global high-resolution thermospheric imaging instrument. The University of Texas in Dallas has developed the ion velocity meter. The spaceship was built by Northrop Grumman of Dulles, Virginia. The Mission Operations Center at UC Berkeley's Space Sciences Laboratory is tasked with running the ICON mission.
ICON – Spacecraft and Instruments
The ICON science payload is on an ATK LEOStar-2 orbital spacecraft. With the payload attached, the spacecraft weighs about 600 pounds and measures 3 feet by 6 feet.
ICON flies orbitally around the Earth with a 27 degree incline and a height of approximately 360 miles. This enables it to observe the ionosphere around the equator. ICON focuses its instruments on the events at the lowest limit of space at a distance of 55 miles to 360 miles.
ICON introduces four instruments to collect images of the ionosphere and to directly measure ionospheric properties of the space environment through which it flies. Together, the instrument suite provides a perspective that would otherwise require two or more orbiting spacecraft. The instruments provide a first comprehensive insight into this crucial region, so that scientists can understand and one day predict what causes disruptions in the ionosphere.
The Four Instruments of ICON:
- MIGHTI: The Michelson Interferometer for the Global High-Resolution Thermosphere Imaging Instrument observes the temperature and velocity of the neutral atmosphere. These winds and temperature changes are caused by weather patterns closer to the Earth's surface. The neutral winds in turn drive the movements of the charged particles in space. MIGHTI was built by the Naval Research Laboratory in Washington, DC.
- IVM: The ion velocity meter measures the velocity of charged particle motion in response to the high pressure of the winds and the electric fields generated by them. The IVM was built by the University of Texas at Dallas.
- EUV: The Extreme Ultra Violet instrument captures images of oxygen glowing in the upper atmosphere to measure the height and density of the ionosphere during the day. This helps to track the response of the space environment to the weather in the lower atmosphere. EUV was built by the University of California at Berkeley.
- FUV: The far-ultraviolet instrument picks up images of the upper atmosphere in the far ultraviolet light. At night, FUV measures the density of the ionosphere and tracks how it reacts to the weather in the lower atmosphere. During the day, the FUV measures changes in the chemistry of the upper atmosphere – the source of the charged gases higher up in space. FUV is being built by the University of California at Berkeley.