 ICON (Explorer 96) satellite | |||||||||||
| Names | Explorer 96 ICON | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mission type | Ionospheric research | ||||||||||
| Operator | UC Berkeley SSL / NASA | ||||||||||
| COSPAR ID | 2019-068A | ||||||||||
| SATCAT no. | 44628 | ||||||||||
| Website | icon | ||||||||||
| Mission duration | 2 years (planned) 4 years, 4 months, 20 days (in progress) | ||||||||||
| Spacecraft properties | |||||||||||
| Spacecraft | Explorer XCVI | ||||||||||
| Spacecraft type | Ionospheric Connection Explorer | ||||||||||
| Bus | LEOStar-2[1] | ||||||||||
| Manufacturer | University of California, Berkeley / Northrop Grumman | ||||||||||
| Launch mass | 288 kg (635 lb) [2] | ||||||||||
| Dimensions | Height: 193 cm (76 in) and 106 cm (42 in) of diameter [3] Solar panel: 254 × 84 cm (100 × 33 in) | ||||||||||
| Power | 780 watts | ||||||||||
| Start of mission | |||||||||||
| Launch date | 11 October 2019, 02:00 UTC[4] | ||||||||||
| Rocket | Pegasus XL (F44) | ||||||||||
| Launch site | Cape Canaveral Skid Strip, Stargazer [5] | ||||||||||
| Contractor | Northrop Grumman | ||||||||||
| Entered service | November 2019 | ||||||||||
| Orbital parameters | |||||||||||
| Reference system | Geocentric orbit | ||||||||||
| Regime | Low Earth orbit | ||||||||||
| Perigee altitude | 575 km (357 mi) | ||||||||||
| Apogee altitude | 603 km (375 mi) | ||||||||||
| Inclination | 27.00° | ||||||||||
| Period | 97.00 minutes | ||||||||||
| |||||||||||
Explorer program | |||||||||||
Ionospheric Connection Explorer (ICON) [6] is a satellite designed to investigate changes in the ionosphere of Earth, the dynamic region high in our atmosphere where terrestrial weather from below meets space weather from above. ICON studies the interaction between Earth's weather systems and space weather driven by the Sun, and how this interaction drives turbulence in the upper atmosphere. It is hoped that a better understanding of this dynamic will mitigate its effects on communications, GPS signals, and technology in general.[6][7] It is part of NASA's Explorer program and is operated by University of California, Berkeley's Space Sciences Laboratory.[8]
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,[9] excluding launch costs.[10] The principal investigator of ICON is Thomas Immel at the University of California, Berkeley.[9][11]
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.[12] ICON was successfully launched on 11 October 2019, at 02:00 UTC.[4]
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Ionospheric Connection Explorer (ICON) (Thomas Immel)
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NASA's Ionospheric Connection Explorer to analyse the atmosphere
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Pegasus XL launches ICON (Ionospheric Connection Explorer)
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Countdown to T-Zero: ICON Satellite to Study Space Weather
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The Making of NASA’s ICON Mission
Transcription
I’m sorry I introduced myself this morning, I believe as the project manager of this mission. That’s west coast jet lag setting in. I am the principal investigator for the Ionospheric Connection Explorer, which we call ICON. I like to point out, I didn’t even have time to pull down everyone’s logos, but we have a number of people working on this project including Peter Harvey and Ellen Taylor, who were on THEMIS, Stephen Mende, who worked on IMAGE and several other missions, Chris Englert, a number of great people with hardware experience. I am also going to work on that one-slide summary, not there yet, but I do have just a few slides, oh gosh I guess I could have checked this out. Next slide please. So I want to give you a scientific summary because I give you some indication of why we are excited about this mission and why we really want to do this and we think we got a good way of going about it. I like to say this is a heliophysics mission studying the equatorial ionosphere of the earth, mainly the focus because the densest plasma between earth and sun is created and trapped in the magnetic field of Earth’s equatorial ionosphere. And as such, it is an excellent natural plasma laboratory for a number of natural plasma processes, universal processes occur near the equator. Now one of these is a light. So if everyone can see that, there have been a number of images from LEO, high-Earth orbit, and now new platforms, including radio tomographic platforms that produce images of the earth, be that through a photometer , from Dynamics Explorer, which first showed us the indication of the equatorial air glow bands and these eclipse, this is sort of an iconic image of the Space Age really I think, which shows the Aura, the earth’s exosphere, and the equatorial air glow bands that straddle the magnetic equator. Later missions, including IMAGE, FUV imager. This is a FUV picture, far ultraviolet. Another FUV image here from IMAGE shows real interesting structure in these bands and of course TIMED launched in 2002, gave us a very good close look at these bands and gave us an indication how variable they were. Also point out, there’s a number of scientific processes that have been discovered, or a number of physical processes that surprised everyone when they were found this decade, such as the extraction of plasma from the low latitudes and drawing them over up into the high latitudes into the polar regions over D.C., here showing the East Coast of the U.S being inundated high density plasma from low latitudes. And then this picture here shows what looks like two different color bars, but these are two different images from conjugate points of the earth 6,000 miles apart. One in Australia, this is in Darwin and one in Japan, showing these conjugate waves in the ionosphere coming from no one knows what. So anyway, after a decade of scientific surprises, it’s clear without a complete set of observations of all the drivers and effects in this remarkable region of space we cannot answer the high priority scientific questions that are now plain. Next slide please. And these are average pictures of the ionosphere. This one is taken from TIMED in July of 2002. This is January 2003, this is a Mercator plot, magnetic coordinates. This is just straddling the equator, see this massive change in the ionosphere. That would have never been predicted by anyone and couldn’t be explained for awhile when TIMED found it until, at the same time, scientific models started showing that when you introduce energy into the atmosphere and in the troposphere in the rain forest, the atmosphere starts beginning to move together and tides form these large temperature enhancements. This is 100 kilometer altitudes, so at the edge of space. You’ve gotten these very large changes in temperatures and winds and that really looked to be connected. Next slide please. And we can simulate that effect. And if you look from the north to south and the equator, south to north, it gets bright, dim, bright again and we can simulate, we can say okay this is sort of the range. This is sort of the dim portion. This is a bright ionosphere. We can simulate that by changing the electric field and the same electric ionospheric model. There is a number of the drivers you can push in the same model to give you pretty much the same answer. So the point is we want to separate out these drivers to understand the system response. Next slide please. So ICON is designed in part to answer those kinds of questions. ICON carries a wind imager measuring winds 90 degrees offset. You can rebuild from separate observations a wind vector at every particular point where these fields of view eventually cross. I’ll help understand that in a minute. So in the Rand direction, there is a field of view that we keep clear for the electric plasma drift instrument, which gives you electric fields and off to the side we do imaging. So that is ICON in its 24-degree orbit at 550 kilometers altitude, comes flying along past point in the ionosphere that you are interested in. First, it takes a wind measurement at the foot point of these magnetic field lines and also in the ionosphere. And then later it’s on those fields lines intersecting that position measuring the electric field on that field line where your measuring the winds. Also, it takes images in EUV and the FUV to retrieve all the other important parameters and then three-and-half minutes later, makes the final wind measurement. So are these are the instruments and the quantities were after to answer these questions. And I think that is it.
Overview
ICON will perform a two-year mission to observe conditions in both the thermosphere and ionosphere.[9] ICON is equipped with four instruments: a Michelson interferometer, built by the United States Naval Research Laboratory (NRL), measures the winds and temperatures in the thermosphere; an ion drift meter, built by University of Texas at Dallas, measures the motion of charged particles in the ionosphere; and two ultraviolet imagers built at University of California, Berkeley, 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.[3] Improved understanding of this environment can help predict such events and improve satellite safety and design.[3]
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.[13][14] 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.[5] 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.[13] The October 2018 launch from Florida was scheduled after an initial review of the avionics issues.[13] 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 carries 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 has a mass of 130 kg (290 lb) and are listed below:[15][16]
- Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI)
- Ion Velocity Meter (IVM) is 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.[15] MIGHTI measures wind speed and temperature between 90 km (56 mi) and 300 km (190 mi) in altitude.[17] The velocity measurements are gathered by observing the Doppler shift in the red and green lines of atomic oxygen. This is done with the Doppler Asymmetric Spatial Heterodyne (DASH) which uses échelle gratings.[17] The temperature measurements are done by photometeric observations with a CCD.[17] MIGHTI is designed to detect wind speeds as low as 16 km/h (9.9 mph), even though the spacecraft is traveling at over 23,000 km/h (14,000 mph) (to stay in orbit).[18]
IVM collects in situ data about ions in the local environment around the spacecraft, whereas EUV and FUV are spectrographic imagers. EUV is 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 is 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 [18]
The solar panel produces 780 watts,[2] but the observatory's power consumption ranges between 209 and 265 watts when in science mode.[3]
Mission Operations
Once launched, and for the duration of its two-year science mission, the ICON observatory is controlled and operated by the Mission Operations Center (MOC) at the Space Sciences Laboratory at University of California, Berkeley.[19] The UCB MOC currently operates seven NASA satellites. ICON was placed into a 27.00° inclination orbit, and communications are through Tracking and Data Relay Satellite System (TDRSS), the orbiting NASA communications network. Ground contacts with ICON are performed mainly from the Berkeley Ground Station, an 11 m (36 ft) dish, with backup contacts out of Wallops Flight Facility (WFF), Virginia and Santiago, Chile.
Loss of Contact
The NASA ICON team lost contact with the ICON spacecraft on 25 November 2022. A fail-safe system designed to reset the spacecraft computer after 8 days with no receipt of commands from the ground failed to restore communications after it elapsed on 5 December 2022.[20]
See also
References
- ^ "ICON: Exploring where Earth's Weather meets Space Weather" (PDF). University of California, Berkeley. Retrieved 4 February 2018.
- ^ a b ICON Factsheet Archived 24 October 2018 at the Wayback Machine, Northrop Grumman, Accessed: 24 October 2018
- ^ a b c d ICON, October 2018, NASA
This article incorporates text from this source, which is in the public domain.
- ^ a b NASA Launches Long-Delayed ICON Space Weather Satellite to Study Earth's Ionosphere, Amy Thompson, Space.com, 11 October 2019
- ^ a b Granath, Bob (21 September 2018). "NASA's ICON launch now targeted for October 26 - ICON Mission". NASA. Retrieved 21 September 2018. This article incorporates text from this source, which is in the public domain.
- ^ a b "Ionospheric Connection Explorer". University of California, Berkeley.
- ^ "ICON Mission Overview". NASA. 31 March 2016. Retrieved 4 February 2018. This article incorporates text from this source, which is in the public domain.
- ^ Sanders, Robert (16 April 2013). "UC Berkeley selected to build NASA's next space weather satellite". Berkeley News. Retrieved 19 January 2016.
- ^ a b c Harrington, J. D. (5 April 2013). "NASA Selects Explorer Investigations for Formulation". NASA. Retrieved 6 April 2013. This article incorporates text from this source, which is in the public domain.
- ^ Leone, Dan (20 October 2015). "Heliophysics Small Explorer Solicitation Set for First Half of 2016". SpaceNews. Retrieved 21 October 2015.
- ^ "ICON Project Management". University of California, Berkeley. Retrieved 14 October 2017.
- ^ Bartels, Meghan (23 October 2018). "ICON of Delay? NASA, Northrop Grumman Postpone Earth Satellite Mission Yet Again". SPACE.com. Retrieved 9 March 2019.
- ^ a b c Gebhardt, Chris (5 October 2018). "Northrop Grumman Innovation Systems updates ICON launch status". NASASpaceFlight.com. Retrieved 26 October 2018.
- ^ Clark, Stephen (10 November 2017). "Launch of NASA ionospheric probe delayed to examine rocket issue". Spaceflight Now. Retrieved 26 October 2018.
- ^ a b "Ionospheric Connection Explorer (ICON) Satellite". Aerospace Technology. Retrieved 11 October 2018.
- ^ "ICON (Ionospheric Connection Explorer) - Satellite Missions". directory.eoportal.org. Archived from the original on 4 August 2019. Retrieved 11 October 2018.
- ^ a b c Englert, Christoph R.; Harlander, John M.; Brown, Charles M.; Marr, Kenneth D.; Miller, Ian J.; Stump, J. Eloise; Hancock, Jed; Peterson, James Q.; Kumler, Jay (20 April 2017). "Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI): Instrument Design and Calibration". Space Science Reviews. 212 (1–2): 553–584. Bibcode:2017SSRv..212..553E. doi:10.1007/s11214-017-0358-4. ISSN 0038-6308. PMC 6042234. PMID 30008488.
- ^ a b Frazier, Sarah (18 October 2018). "Counting Down to the Ionospheric Connection Explorer (ICON) Launch". SciTechDaily. Retrieved 26 October 2018.
- ^ Simon, Matt (17 October 2019). "UC Berkeley Was About to Launch a Satellite. Then PG&E Said It Was Cutting Power". Wired (San Francisco, Calif.). Wired. ISSN 1059-1028. Retrieved 19 October 2019.
- ^ "ICON Mission Out of Contact – ICON Mission". blogs.nasa.gov. 7 December 2022. Retrieved 9 December 2022.
External links
Media related to Ionospheric Connection Explorer at Wikimedia Commons
- ICON website by NASA
- ICON website by University of California, Berkeley
This page was last edited on 25 February 2024, at 02:34