astronomy

Ionospheric Connection Explorer

Ionospheric Connection Explorer is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ionospheric Connection Explorer rather than just read about it. In short: Ionospheric Connection Explorer (ICON) is a defunct NASA satellite designed to investigate changes in the ionosphere of Earth, the dynamic region high in the atmosphere where terrestrial weather from below meets space weather from above. ICON studied the interaction between Earth's weather systems and space weather driven by the Sun, and how this interaction drives turbulence in the upper atmosphere.

Key takeaways

Ionospheric Connection Explorer belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ionospheric Connection Explorer to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ionospheric Connection Explorer from memory before moving on to harder problems.

Reference excerpt

Ionospheric Connection Explorer (ICON) is a defunct NASA satellite designed to investigate changes in the ionosphere of Earth, the dynamic region high in the atmosphere where terrestrial weather from below meets space weather from above. ICON studied the interaction between Earth's weather systems and space weather driven by the Sun, and how this interaction drives turbulence in the upper atmosphere. NASA hoped that a better understanding of this dynamic would mitigate its effects on communications, GPS signals, and technology in general. It was part of NASA's Explorer program and was operated by University of California, Berkeley's Space Sciences Laboratory. On 12 April 2013, NASA announced that ICON, along with Global-scale Observations of the Limb and Disk (GOLD), had been selected for development with the cost capped at US$200 million, excluding launch costs. The principal investigator of ICON was Thomas Immel at the University of California, Berkeley. ICON was originally scheduled to launch in June 2017 and was repeatedly delayed because of problems with its Pegasus XL launch vehicle. It was next due to launch on 26 October 2018 but the launch was rescheduled to 7 November 2018, and postponed again just 28 minutes before launch. ICON was successfully launched on 11 October 2019, at 02:00 UTC. On 25 November 2022, contact with ICON was unexpectedly lost for unclear reasons. In July 2024, the mission was formally ended after repeated attempts to regain contact with the satellite had failed.

Overview

ICON was designed to perform a two-year mission to observe conditions in both the thermosphere and ionosphere. ICON was equipped with four instruments: a Michelson interferometer, built by the United States Naval Research Laboratory (NRL) to measure the winds and temperatures in the thermosphere; an ion drift meter, built by University of Texas at Dallas to measure the motion of charged particles in the ionosphere; and two ultraviolet imagers built at University of California, Berkeley to observe the airglow layers in the upper atmosphere in order to determine both ionospheric and thermospheric density and composition. Many low-Earth orbiting satellites, including the International Space Station (ISS), fly through the ionosphere and can be affected by its changing electric and magnetic fields. The ionosphere also acts as a conduit for many communications signals, such as radio waves and the signals that make GPS systems work. The ionosphere is where space weather manifests, creating unexpected conditions; electric currents can cause electrical charging of satellites, changing density can affect satellite orbits, and shifting magnetic fields can induce current in power systems, causing strain, disrupting communications and navigation or even triggering blackouts. Improved understanding of this environment can help predict such events and improve satellite safety and design.

Launch planning Upon initial completion and delivery of the ICON observatory in 2016, launch plans centered around the launch range at Kwajalein Atoll in the Pacific Ocean. ICON was originally scheduled to launch in June 2017, but was repeatedly delayed because of problems with its Pegasus XL launch vehicle. The launch vehicle was mated to its air-launch aircraft Stargazer for a launch attempt in June 2018. This launch was cancelled days before because the rocket showed issues on the first leg of the ferry flight to Kwajalein. Given the availability of the launch range in Cape Canaveral, and a review of the suitability of this site, it was adopted as the ICON launch site. The October 2018 launch from Florida was scheduled after an initial review of the avionics issues. Whereas the delays in 2017 were due to concerns with rocket-payload and fairing separation systems, the 2018 delays were due to noise in the rocket avionics systems. The issues resulted finally in the 2018 Cape Canaveral launch being scrubbed minutes before the scheduled launch. These issues were ultimately resolved and ICON launched from Cape Canaveral on 11 October 2019 at 02:00 UTC. After an approximately month-long commissioning period, ICON began sending back its first science data in November 2019.

Science payload ICON carried four scientific instruments designed to image even the faintest plasma or airglow to build up a picture of the ionosphere's density, composition and structure. The complete instrument payload manifest had a mass of 130 kg (290 lb) and is listed below:

Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) Ion Velocity Meter (IVM), an ion drift meter Extreme Ultra-Violet (EUV), an imager Far Ultra-Violet (FUV), an imager MIGHTI was developed at the United States Naval Research Laboratory (NRL), IVM at the University of Texas, and EUV and FUV were developed at the University of California, Berkeley. MIGHTI measured wind speed and temperature between 90 km (56 mi) and 300 km (190 mi) in altitude. The velocity measurements were gathered by observing the Doppler shift in the red and green lines of atomic oxygen. This was done with the Doppler Asymmetric Spatial Heterodyne (DASH) which used échelle gratings. The temperature measurements were done by photometeric observations with a CCD. MIGHTI was designed to detect wind speeds as low as 16 km/h (9.9 mph), even though the spacecraft was traveling at over 23,000 km/h (14,000 mph) (to stay in orbit). IVM collected in situ data about ions in the local environment around the spacecraft, whereas EUV and FUV were spectrographic imagers. EUV was a 1-dimension limb imager designed to observe height and density of the daytime ionosphere by detecting the glow of oxygen ions and other species at wavelengths between 55 and 85 nm. FUV was a 2-dimension imager that observes the limb and below at 135 and 155 nm, where bright emissions of atomic oxygen and molecular nitrogen are found. The solar panel produced 780 watts, but the observatory's power consumption ranged between 209 and 265 watts when in science mode.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Ionospheric Connection Explorer

Start with the simplest possible case. Write down what Ionospheric Connection Explorer claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ionospheric Connection Explorer before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ionospheric Connection Explorer ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ionospheric Connection Explorer

In research: Ionospheric Connection Explorer appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ionospheric Connection Explorer in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ionospheric Connection Explorer is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2019 in the United States, Earth observation satellites of the United States, Explorers Program, so understanding it makes those chapters shorter.
In everyday life: Look for Ionospheric Connection Explorer outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ionospheric Connection Explorer in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ionospheric Connection Explorer means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ionospheric Connection Explorer out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ionospheric Connection Explorer in simple terms?

Why does Ionospheric Connection Explorer matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ionospheric Connection Explorer?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ionospheric Connection Explorer.