By the year 2005, the statistics for our satellite resources and their utilization are nothing less that incredible. Not including military applications, meteorology, and research applications, the satellite telecommunications industry, alone, represents a $97 billion per year business much of which wouldn't exist without the satellite resources.

As of 2005, there are a total of 967 operating satellites, with 437 in LEO, 132 in MEO and 367 in GEO. The replacement cost (including launch) of this resource is about $190 billion, of which $55 billion is launch costs.

Operating satellite archive [Excel Spreadsheet]

Satellites represent an entirely unique technology that has grown up simultaneously with our understanding of the geospace environment. There has never existed a time when we did not fully comprehend how space weather impacts satellite technology. Despite the nearly 40 years that have gone by since the beginning of the Space Age, satellite technology is, in many ways, still in its infancy. The following is a summary of satellites that have been affected by space weather events, and a description of the major satellite zones surrounding Earth. The information is excerpted from The 23rd Cycle and a NASA Report on Spacecraft anomalies. Because they are so numerous, not all of the electrostatic discharging anomalies for satellites mentioned in the NASA report are listed below.

Low Earth Orbit (LEO) spans a zone approximately from 200 to 1,500 miles above the surface. The most common satellites in LEO include ones designed for military 'espionage' applications, scientific research, and a growing number of satellite phone networks (e.g. Iridium, Globalstar, Orbcom). The biggest space weather effect to LEO satellites is the atmosphere of Earth itself, and the way it inflates during solar storm events. This causes high-drag conditions that lower satellite orbits by tens of miles at a time. In addition, the most intense regions of the van Allen radiation belts reach down to 400 miles over South America. Satellites in LEO will spend part of their orbital periods flying through these clouds of particles. The residents of this region that show space weather impacts are:

Hubble Space Telescope - This $1.5 billion scientific research satellite launched in 1990, orbits at an altitude of 360 miles (600 km) for easy servicing by the Space Shuttle. It is scheduled to be decommissioned in ca 2009 when its gyros begin to fail. The data are constantly affected by cosmic rays and by high-energy particles, especially during solar storms. These 'glitches' are deleted from the data during ground-based processing and scientific analysis. The solar panels suffer the same degradation from cosmic rays as other satellites. On May 7, 1990 'bit-flips caused when the satellite entered the South Atlantic Anomaly region over South America caused controllers to modify the onboard software. On June 20, 1990 the SAA also caused photomultiplier tube anomalies in the FIne Guidance Sensor, producing guide star acquisition errors. Subsequently, FGS use was suspended during SAA passage.

International Space Station - A $ 95 billion manned operating platform with a 12-year lifespan, it is in a high-inclination orbit with a Space Shuttle-accessible altitude of 219 miles (perigee 354 km). It requires re-boosting several times every year because atmospheric drag is constantly decreasing its altitude by a kilometer every 12 days. Solar storms heat the upper atmosphere causing increasres drag which accelerates the orbit decay. Data collected by NASA and a Russian-Austrian collaboration show that astronauts on the ISS are subjected to about 1 millisievert (100 milliRem) of radiation per day; about the same radiation exposure as someone would get from natural sources on Earth in a whole year.

Space Shuttle - March 13, 1989 - Pressure sensor gives false readings during the 'Quebec Blackout' space weather event. Atlantis (October 18-24, 1989) astronauts report eye flashes even inside the most heavily shielded area of the space shuttle. This pattern of astronaut eye flashes is a recurring phenomenon for all the major solar flares recorded since the Space Shuttle began flying.

Medori II - This $630 million research satellite (ADEOS-II) owned by Japan failed as a result of the major solar storm that pummeled Earth between October 22-30, 2003. In an article "Space Anomaly and Space Environment, Space Weather and Satellite Alert System" by Tateo Goka et al. (Japan Aerospace Exploration Agency - JAXA) published in 2004: "The Advanced Earth Observing Satellite II (ADEOS-II), also called Midori-II in Japanese, a low-altitude polar sun-synchronous satellite with an altitude of 800 km, suffered a catastrophic failure during an October [space weather] storm. Solar cell power output dropped from 6 kW to 1 kW in three minutes from (16:13 to 16:16 (UT)) on October 24. ..It was probable that a short- or open- circuit failure occurred on the solar array paddle or solar array paddle harness. For the latter, the laboratory test verified that the sustained arcing between the harnesses could destroy the bundled power lines. Space environment analysis demonstrated that the >30keV electron fluence (observed by NOAA-17) was [one hundred] times greater than during a quiet day, just a quarter hour before the ADEOS-2 power down outage anomaly [occurred] over the north pole auroral region" Reference: H. Maejima, S. Kawakita, H. Kusawake, M.Takahashi, T. Goka, T. Kurosaki, M. Nakamura, K. Toyoda, M. Cho, Investigation of Power System Failure of a LEO Satellite, AIAA, Proceeding of 2nd International Energy Conversion Engineering Conference (IECEC), Providence, RI, (2004). "

Adeos-1 - On September 20, 1997, the $474 million Adeos research satellite launched by Japan a year earlier into an 803-km orbit, began to malfunction. According to a report in Space News, "...Cosmic rays were found to have damaged the main onboard computer, which caused it to shut down all nonessential systems, including the sensors, forcing scientists to reprogram its software"

Equator-S- On May 1, 1998 , the $12 million German research satellite Equator-S owned by the Max Planck Institute lost its backup processor. According to an announcement by the Institute at the official web site for this satellite, "If a latch-up caused by penetrating particle radiation was the cause, there is hope that it may heal itself upon the next eclipse because of the complete temporary switch-off of the electrical system"

Skylab - On July 11, 1979 this abandoned, unmanned space station in a 435-km orbit, prematurely re-entered Earth's atmosphere because of the increased drag caused by heightened solar activity. This uncontrolled reentry was a major news story.

Solar Maximum Mission (SMM) - This research satellite launched on February 14, 1980 into a 574-km orbit lost 8k out of its 48k of onboard memory because of a 'hard' cosmic ray hit in early January, 1986.

FY-1 Launched on September 7, 1988 into a 900 km orbit, after 39 days in orbit, this Chinese satellite experienced an electrostatic discharge caused a failure of the attitude control system that ended the mission.

Mid Earth Orbit (MEO) between 6,000 and 12,000 miles was originally used by the Telstar 1 satellite, but is currently not economically worth the incremental advantage it provides for communication satellites. Research satellites such as NASA's IMAGE satellite, and certain types of military communications and global positioning satellites are commonly found here. The most famous occupant of these regions subject to solar storms are:

Global Positioning System (GPS) - Originally used by the US military, there are now 100 times more clients in the civilian sector using this satellite system to determine location to better than 3-meter accuracy. This $6 billion network of 24 satellites and 5 spares launched between 1978-2002 have been specifically designed to be radiation-hardened so that they can survive constant encounters with the high-energy particles in the van Allen radiation belts. They orbit at an altitude of 10,900 miles, and have lifetimes of 10 years. There have been three systems (Block I, Block II and Block IIR) installed since the first Navstar satellites were launched in 1973. The next upgrade, Block III, is planned for 2005 or 2007 when the satellites will be replaced at a cost of about $80 million each. The GPS system is affected by solar storms, which cause the position error to increase by factors of 3 to 4 times for the duration of the storm. Of the 33 GPS satellites still operating, 19 are older than their 8-year design lifetime and support a $22 billion a year civilian global positioning industry.

Telstar-1 - The first satellite to fall victim to space weather effects was, in fact, the one of the first commercial satellites ever launched into orbit in July 1962: Telstar 1. In November of that year, it suddenly ceased to operate. From the data returned by the satellite, Bell Telephone Laboratory engineers on the ground tested a working twin to Telstar by subjecting it to artificial radiation sources, and were able to get it to fail in the same way. The problem was traced to a single transistor in the satellites command decoder. Excess charge had accumulated at one of the gates of the transistor, and the remedy was to simply turn of the satellite for a few seconds so the charge could dissipate. This, in fact, did work, and the satellite was brought back into operation in January, 1963. The source of this information was not some obscure technical report, or an anecdote casually dropped in a conversation. This example of energetic particles in space causing a satellite outage was so uncontroversial at that time, it appeared under the heading 'Telstar' in the 1963 edition of the World Book Encyclopedia's 1963 Yearbook.

ETS-6. This $415 million Japanese research satellite failed to reach its intended geosynchronous orbit, and radiation from the van Allen Belts quickly eroded the solar panel power levels causing the satellite to fail within one year. The 98-foot solar panel had produced 5800 watts on t he day of deployment, September 3, 1994, but after 10 days the levels were 5300 watts and by the end of September 4700 watts, and by the end of the year the levels would be near 2700 watts, which was too low to operate the satellite.

Hipparcos - Although not technically in a MEO orbit, its 315 x 22,300 km elliptical orbit covers most of MEO space. This astronomy research satellite failed on August 15, 1993 after three years of service. In June 1993, the satellite suffered difficulties in communication between ground stations and the flight computer. The cause of the problem was attributed to radiation damage to certain components. Attempts to restart operations proved unsuccessful so the mission was terminated.

Geostationary Orbits (GEO) at 22,300 miles are unique in that, as Arthur C. Clarke predicted in the 1940's, satellites positioned there will orbit Earth once every 24-hours and appear to be 'stationary' above the surface. Communications satellites are by far the most common and financially lucrative satellites found in GEO orbits, along with military and civilian weather satellites and satellites designed for espionage. The median age of GEO satellites in 2004 is 9 years. Most satellites have a design life of 10-15 years, so nearly half of the known GEO satellites are already older than their designed lifetimes.An extensive list of operating communication satellites is found at and in Eric Johnson's 2004 tabulation. Some famous examples that have has space weather problems are:

Tempo-2 The new solar cell design on this satellite would be wired to produce 60 volts per module to keep the weight and size of the solar panels within the limits set by the cost of the satellite. One of these panels, incidentally, could comfortably supply the needs of a medium-sized house. But the Tempo-2 failure on April 11, 1997 uncovered a potentially fatal problem with these new panels. They were susceptible to energetic particle impacts, which caused miniature lightning bolts to flare-up and short circuit sections of the panels.

Telstar 401 - The much-publicised failure of this $200 million communication satellite is widely acknowledged to have been caused by a massive solar storm that disturbed the magnetosphere beginning on January 9, 1997 and ending with the satellites failure on January 13th. This outage affected the $712 million sale of AT&Ts Skynet telecommunications resources to Loral Space and Communications Ltd.

GOES-7 - This $55 million weather satellite loses half of its 10-year mission lifetime from a single solar flare in March 1989. During an intense period of solar flares from March 22-24, 1991, the solar panels were degraded so that the satellite lost 2-3 years of planned lifetime from this one event alone.

GEOS-6 - August 15-16, 1989 - a powerful solar flare caused half of the GEOS-6 telemetry circuits to fail immediately.

GOES-5 - On October 19, 1989 a powerful solar flare damaged the solar array electronics and caused a 0.5 ampere decrease in solar panel output. Ten SEUs were recorded in 1989, of which six were associated with solar flares.

NOAA-10 - On March 13, 1989 the satellite experienced excessive x-axis gyro speeds due to 'magnetic momentum unloading' that caused the roll / yaw coil to switch to backup mode. Operators suspected the anomaly was caused by a solar storm. On October 1, 1989 a 28-volt power switch indicated an undesired 'on' setting that required controllers to reset it. They suspected a solar storm was the cause.

NOAA-9 - High solar activity in mid-March 1989 caused unusual momentum wheel activity that caused the roll / yaw coil to switch to backup mode. Operators suspected the anomaly was caused by a solar storm - similar to the problems with NOAA-10.

Anik -E1 - January 20, 1994 at 12:40 PM the Canadian communication satellite began to roll end-over-end uncontrollably. The Canadian Press was unable to deliver news to over 100 newspapers and 450 radio stations for the rest of the day, but was able to use the Internet as an emergency back-up. Telephone users in 40 northern Canadian communities were left without service. It took over seven hours for Telesat Canada's engineers to correct Anik E1's pointing problems using a back-up momentum wheel system. Telesat Canada publicly acknowledged the cause-and-effect relationship between space weather and the satellite malfunction in press releases and news conferences following the outage. They also admitted that the Anik space weather disturbance which had ultimately cost their company nearly $5 million to fix, was consistent with past spacecraft-affecting events they had noticed and that very similar problems had also bedeviled the Anik-B satellite 15 years earlier.

Anik-E2 - January 20, 1994 at 9:10 PM, the Anik E2 satellite's momentum wheel system failed, but its backup system also failed, so the satellite continued to spin slowly, rendering it useless. This time, 3.6 million Canadians were affected as their major TV satellite went out of service. Popular programs such as MuchMusic, TSN and the Weather Channel were knocked off the air for three hours while engineers rerouted the services to Anik E1. For many months, Telesat Canada wrestled with the enormous problem of trying to re-establish control of Anik E2. They were not about to scrap a $300 million satellite without putting up a fight. After five months of hard work, they were at last able to regain control of Anik E2 4 on 21 June 1994. The bad news is that, instead of relying on the satellite's now useless pointing system, they would send commands up to the satellite to fire its thrusters every minute or so to keep it properly pointed. Telesat Canada publicly acknowledged the cause-and-effect relationship between space weather and the satellite malfunction in press releases and news conferences following the outages. They also admitted that the Anik space weather disturbance which had ultimately cost their company nearly $5 million to fix, was consistent with past spacecraft-affecting events they had noticed and that very similar problems had also bedeviled the Anik-B satellite 15 years earlier.

TDRSS-1 - The first satellite in the NASA, Tracking and Data Relay Satellite System was launched in April 1983, and from that time onwards, the satellite has been continuously affected by soft SEUs. The satellite anomalies affected the spacecraft's Attitude Control System, and like mosquitoes on a warm day, they remain a constant problem today. The SEUs have been traced to changes in the computer's RAM, and the most serious of these SEUs were considered mission-threatening. If left uncorrected, they could lead to the satellite tumbling out of control. Ground controllers have to constantly keep watch on the satellite's systems to make certain it keeps its antennas pointed in the right direction. This has become such an onerous task that one of the ground controllers, the late Don Vinson, once quipped, "If this [the repeated SEU's] keeps up, TDRS will have to be equipped with a joystick" The problems with TDRSS-1 quickly forced NASA to redesign the next satellites in the series, TDRSS-3 and 4 (TDRSS-2 was lost in the Challenger accident), and the solution was fortunately very simple. In engineering-speak, "The Fairchild static, bi-polar 93L422 RAMS were swapped for a radiation-hardened RCA CMM5114 device based on a different semiconductor technology".

Intelsat-K satellite began to wobble on January 20, 1994, and experienced a short outage of service. The satellite had experienced an electrostatic discharge presumably caused by a space weather event which had started in January 13th. The discharge disabled the momentum wheel control circuitry on the satellite causing it to wobble and produce antenna pointing fluctuations in coverage on the ground. A backup system was turned on and the satellite resumed operation the same day. The Intelsat-K and the Anik E1 and E2 satellites are of the same satellite design. The crucial difference however, is that the Intelsat Corporation specifically modifies its satellites to survive electrostatic disturbances including solar storms and cosmic rays. This allowed the Intelsat-K satellite to recover quickly following the storms that disabled the unmodified Anik satellites.

Marecs-1. During a period of intense solar activity, this satellite suffered severe damage to its solar panels which led to satellite failure on March 25, 1991.

Anik-B - February 8, 1986 - After a large 18-hour magnetic storm, the satellite's electromagnetic torquing coils were upset by the Earth's changing magnetic field, and position errors were generated instead of being automatically corrected by the onboard attitude system. Thrusters had to me manually used by ground controllers to maintain the satellite's orientation.

BS-3A - On February 22, 1994 the satellite suffered a 60-minute telemetry outage because of an electrostatic discharge.

GMS-4 (Himawari-4) This Japanese geostationary meteorology satellite experienced electrostatic discharges in January and July 1991 which caused the Visible-Infrared Spin Scan Radiometer to enter an unscheduled gain setting.

FLTSATCOM 6071 - Between March-June 1987, this satellite experienced 5 deep dielectric charging events that resulted in low-level logic anomalies.

AUSSAT A2 Experienced 33 electrostatic discharges that led to anomalous phantom commands between May 1986 and June 1990, and that affected the attitude control system

Arabsat 1A - On March 15, 1985 this satellite lost power, attitude control and gyros soon after launch which forced controllers to employ manual station-keeping, but on June 1, 1986 an electrostatic discharge caused loss of Earth lock and the satellite was designated an orbital 'spare'.

DSCS-II (9431) - June 2, 1973 the satellite failed because a high-energy discharge caused by spacecraft charging from a magnetic storm had caused a sudden power failure. This event caused a joint NASA Air Force investigation of spacecraft charging to evaluate and understand its causes.

Data Relay Test Satellite (DRTS) - On October 28, 2003 at 18:42 UT just after a powerful X17 solar flare, the satellite entered 'safety mode' and shut down all non-critical operations. The satellite was recovered on November 7, 2003.


Interplanetary Missions:

Magellan - During September 29, 1989, a powerful X-ray flare caused power panel and star tracker upsets on NASA's Magellan spacecraft enroute to Venus.

NEAR - On December 20, 1998 the spacecraft was just beginning a crucial 20-minute burn of its thruster to ease it gently into orbit around the asteroid Eros. The thrusters were turned on by the satellite following a pre-recorded set of instructions, but suddenly the spacecraft aborted its firing. For 27 hours, the satellite refused to speak to Earth until ground controllers finally got a weak reply from it. They quickly uploaded commands for NEAR to take as many pictures as it could as it hurled past Eros. Why had the carefully planned rocket firing gone awry in mid-execution? By June 1999 engineers had run numerous tests using identical computers and software, but were unable to reproduce the glitch. A similar thruster firing had to be commanded exactly on January 3, 1999 so that NEAR could return for a second orbit insertion try in February 14, 2000. This time there was no glitch.