DTIC ADA372283: Space Tracks: A Naval Space Command Bulletin on Naval Space Issues and Initiatives, January 2000.

20 Pages·2.3 MB·English

by  Defense Technical Information Center

January 2000
SPACE TRACKS
A NAVAL SPACE COMMAND BULLETIN ON NAVAL SPACE ISSUES AND INITIATIVES
IN THIS ISSUE
Navy Communications Satellite Successfully Launched • Page 3
Mobile Satellite Services Hold
Potential for Military • Page 4 DISTRIBUTION STATEMENT A
Approved for Public Release
MUOS Addresses Mobile
Distribution Unlimited
Warfighter Needs • Page 5
Network Installation Doesn't
Slow OPTEMPO • Page 12 Stormy Weather"^
JNavaj Space Command Prep,
Navy Satellite To Chart Star for Solar Maximum # Page
Positions • Page 16
-gjtqUALITI DEFECTED I
NAVSPACECOM
DIRECTORY
Naval Space Command provides direct space support to Fleet and Fleet Marine
Force operational units around the world, whether for routine deployments,
exercises, or actions in response to a crisis situation. We take very seriously
our duty of ensuring that our Sailors and Marines understand what products
are available from space, how to access them, and how to exploit those prod- NAVAL SPACE COMMAND
ucts in the waging of war and peace.
COMMANDER
O Operational Status/Exercise Support Summaries Rear Admiral Thomas E. Zelibor
Naval Space Command maintains a home page on the Global Command and
DEPUTY COMMANDER
Control SystemtTS) accessible to operational U.S. military forces worldwide
Colonel John T. Hill
at http://navspac1.navspace.navy.smil.mil or http://206.36.197.10.
SPACE TRACKS
O Naval Space Operations Center [phone]
Call Toll-Free at 1-888-404-6557. Source of space-related operational intelli-
EDITOR
gence. Space reports and analyses are activated on request and are tailored
Gary R. Wagner
to a deploying unit's operations and geographic area of movement. Tactical
assessments of space system capabilities and vulnerabilities to potentially CONTRIBUTORS
hostile space sensors are also available. Lt.Cmdr. J. J. Kinder
Lt.Cmdr. BrtBaldauf
Lt.Cmdr. Ray Lewis
O Naval Space Support Teams [phone]
J02 Kaye Trammell
Naval Space Support Teams provide tailored information and training at all
Thomas B. Sanford, Bonnie Watson
operational levels to include on-site training, exercise support, and staff aug-
Jonathan P. Boers, Al Sapp
mentation.
PRODUCTION
O Remote Earth Sensing Information Center [phone]
McDonald & Eudy Printers, Inc.
Naval space Command employs imagery from remote Earth sensing satel-
Temple Hüls, Md.
lites to support intelligence, planning, and operations. Our Remote Earth
Sensing Information Center (RESIC) — formerly known as the MSI Cell —
processes Landsat, SPOT, and Controlled Image Base (CIB) data in support of CIRCULATION
Fleet and Fleet Marine Force units. Hardcopy and softcopy products, specifi- B. J. Andersen, Susan Wright;
Administrative Support Branch
cally tailored to users' needs, are produced by RESIC and distributed to sup-
port forces participating in real-world crisis, operations, and exercises. RESIC
products can be produced to support any of the following applications:
Planning Intelligence Prep of the Battlefield
Target Area Analysis Mission Rehearsal
Bathymetry Amphibious Support
Order of Battle Disposition Supplement MC&G Products
Change Detection Trafficability
Broad Area Coverage
SPACE TRACKS is published four times a
year in January, April, July and October
Product requests can be submitted via GENADMIN message to: COMNAV- as an official, authorized publication of
Naval Space Command. Its purpose is
SPACECOM DAHLGREN VA//N313//, via facsimile to DSN 249-6167 or (540)
to discuss naval space issues and initia-
653-6167, via email to [email protected], or via Naval Space Command's tives, and promote a broader awareness
SIPRNET web page. of space support available to the naval
warfighter. Information contained in
Space Tracks does not necessarily reflect
O Internet On-Line Access the official views of the U.S. Government,
Naval Space Command maintains a home page on the World Wide Web at the Department of Defense, or the De-
partment of the Navy. The editorial con-
URL http://www.navspace.navy.mil. Comments or requests for information tent is prepared by the Public Affairs Of-
may be forwarded to the Public Affairs Office via email to gwagner© fice of the Commander, Naval Space
nsc.navy.mil. Command.
Address all correspondence to Editor,
Space Tracks, Naval Space Command
(Code OOP), 5280 Fourth St., Dahlgren, Va.
22448-5300; telephone [phone],
DSN 249-6111, FAX [phone]. Com-
ments or queries may also be forwarded
via email to gwagner® nsc.navy.mil.
SPACE TRACKS • January 2000
recent launch, the UHF Follow-On con-
stellation consists of eight modified 39-
channel Hughes HS-601 satellites and
one in-orbit spare.
The UHF F/O communications sat-
ellites replace the Fleet Satellite Com-
munications (FLTSATCOM) spacecraft
currently supporting the Navy's global
communications network, serving ships
at sea and a variety of other U.S. mili-
tary fixed and mobile terminals. They
are compatible with ground and sea-
based terminals already in service.
Naval Space Command is the satel-
lite communications systems expert
(SSE) for the UHF Follow-On satellite
constellation. The Naval Satellite Op-
erations Center, a component of NAV-
SPACECOM headquartered at Point
Mugu, Calif., executes spacecraft con-
trol, telemetry and monitoring for all
spacecraft in the constellation once they
Deployment tests of a solar wing on the UHF Follow-On F10 spacecraft are complete on-orbit checkout and are
conducted by Hughes Space and Communications Co. technicians, HSC Photo ready for operational use.
The UHF F/O F10 satellite's solar
Navy Communications Satellite array consists of two 34-foot solar wings
that will generate at least 3,800 watts of
Successfully Launched power at the end of the spacecraft's ser-
vice life. F10 is the third satellite to
The U.S. Navy's tenth UHF Follow- awarded to HSC to build the UHF F/O carry the high-capacity Global Broad-
On (UHF F/O) communications satellite constellation and place it in or- cast Service payload consisting of four
satellite was launched from Cape bit. The initial agreement called for 130-watt military Ka-band transponders
Canaveral Florida's Space Launch Hughes to build and launch one satel- with three steerable downlink spot beam
Complex 36B on Nov. 23. The launch lite, with options for nine more, for a antennas and one steerable and one fixed
vehicle was an Atlas IIA with a Centaur total value of $1.9 billion. uplink antenna. This antenna modifi-
upper stage that placed the 7,066-pound In November, SPA WAR announced cation results in a 96 megabits-per-sec-
UHF Follow-On F10 communications a $27.3 million fixed-price-option modi- ond (Mbps) capability.
satellite into an intermediate transfer fication to the original contract to pur- The satellites transmit to small, mo-
orbit of 14,186 nautical miles apogee, chase an 11th UHF Follow-On commu- bile, tactical terminals. UHF satellites F2
155 nautical miles perigee and an incli- nications satellite from HSC. This through F9 are on orbit and operational.
nation of 27 degrees. modification contains 12 option contract UHF Fl is functional, yet in an orbit that
Subsequently, a team of Air Force, line items, which, if exercised, will bring makes it unusable for its original pur-
Navy and Hughes Space and Commu- the total cumulative value of the con- pose because of a launch vehicle fail-
nications Co. (HSC) flight controllers tract modification to $213,286,790. ure. Satellites F8, F9, and F10 carry a
located at the Air Force's 3rd Space Currently, Fll is scheduled to carry Global Broadcast Service Ka-Band pay-
Operations Squadron at Schriever Air UHF and EHF communications capa- load. The GBS capability provides
Force Base, Colo., maneuvered the sat- bility. high-speed, wideband, simplex broad-
ellite into geosynchronous orbit over the The UHF Follow-On communica- cast signals to the warfighter. This in-
Indian Ocean. tions satellite constellation is used to terim GBS package will revolutionize
The Navy Communications Satellite satisfy Department of Defense require- communications for the full range of
Program Office (PMW 146) of the ments for ultra-high-frequency (UHF), DoD's high-capacity requirements,
Space & Naval Warfare Systems Com- extremely-high-frequency (EHF), and from intelligence dissemination to qual-
mand (SPAWAR) in San Diego has Global Broadcast Service (GBS) com- ity-of-life programming. — By Space
overall responsibility for executing the munications, providing fleet broadcast andNaval Warfare Systems Command's
procurement of the UHF communica- to all Navy ships and command and con- Office of Congressional and Public
tions satellites. In July 1988, a fixed- trol networks for selected aircraft, ships Affairs
price contract based on competition was and submarines. Following the most
SPACE TRACKS • January 2000
Mobile Satellite Services for Naval Use
Commerical Systems Show Potential for Military Missions, But Fall Short In Meeting
Requirements for Open-Ocean Coverage and Communications for Ground Units
By Thomas B. Sanford
M*&
M
obile Satellite Service
(MSS) systems are sat-
ellite communications (SAT- IEST
COM) systems, usually in low-Earth
orbit (LEO), that are designed to pro-
«H HURI
vide voice, data or paging services via
satellite to small, handheld terminals
(telephones). Over the past several
J
years, various companies have proposed
and developed systems that may provide t
some or all of the above communica- "i
tions services. Several of these systems
could be used to augment military com- '■ ■ i
munications systems for non-tactical
1 J
purposes.
iiiih^Mk «
Military Requirements I H^ -' sIN^y*«*^
**"y»TrJL
There are many military requirements 1
J^M
for SATCOM systems, including as-
sured access, netted communications,
joint interoperability, global coverage,
communications-on-the-move, point-to-
gT
point and broadcast. The Department
M fa«
of Defense (DoD) examines emerging
commercial SATCOM capabilities, and ¥pk.
may increase the use of commercial sys-
tems in the future. v*W' ."
At present, operational and planned .. .*
narrowband commercial SATCOM sys-
tems are not fully capable of meeting '-*-:-;
the above requirements, nor is there any h}^
great effort being expended by the in- *ä1
volved companies to incorporate most Iridium satellites are the only MSS spacecraft currently operating that use
of these requirements into their systems. crosslinks to help relay communications around the world. Photo Courtesy Iridium
This is because these systems were
designed for commercial (business) use, MSS (EMSS) Concept of Operations satellite crosslinks, or intersatellite links,
and not for military purposes. Most of was approved, DoD had an agreement which are designed to allow a user on
the companies are willing to accommo- with Motorola to use the Iridium sys- the ground to make telephone calls, or
date the government user, as long as tem. This agreement included the use send low-speed data virtually anywhere
extensive changes are not required to of a DoD-owned gateway in Hawaii for in the world, providing the user has di-
their system. Some of them are even all DoD Iridium communications, to al- rect line-of-sight to a satellite. Cross-
willing to make requested changes to low military users to make secure calls links allow a signal to be sent from sat-
their systems, provided the government without the fear of being geolocated. ellite to satellite until it reaches a point
pays for the changes, and provided there over a ground station nearest the call's
are no conflicts with the needs of other Capabilities of MSS Systems destination, without relying on land-
customers. Of the cellular-telephone-like systems, based telephone lines or cellular tele-
MSS systems have been in the plan- Iridium was the first to launch satellites phone sites. Iridium is the only current
ning stages since the early 1990s. In and to go operational. Iridium's poten- LEO MSS system that is designed to use
April 1997, when the Joint Enhanced tial usefulness derives from its use of crosslinks.
SPACE TRACKS • January 2000
There is another type of MSS sys-
tem that does not use crosslinks. This
is known as a bent-pipe system. In this
type of system, the user and a ground
station (gateway) must both be in the
footprint of the same satellite, thereby
possibly limiting the system's ability to
provide adequate coverage in some
open-ocean regions.
When MSS systems were first envi-
sioned, many people thought of them as
a worldwide cellular telephone system.
This image fit the marketing plans of at
least one MSS provider but, in practice,
cellular phones and satellite phones have
a major difference.
; Wsir Q&s *'<&&&&
MSS systems were designed to pro-
vide on-the-move communications
UHF satellite communications work in harsh operational environments to
capability for the business traveler.
support warfighters where they fight, on land or at sea. The joint community
However, they require absolute line-of- insists that MUOS must maintain those qualities. U.S. Navy Photo
sight to the satellite (this is more restric-
tive than cellular phones), making them By Al Sapp Another UHF F/O "look-a-like" con-
unusable on many city streets (due to stellation won't satisfy future needs.
blockage from buildings), inside build- No satellite system is designed to Joint Vision (JV) 2010 doctrine, the U.S.
ings (unless near a window, with a clear last forever. By 2007, Navy ex- military's better way to route the enemy,
path to the satellite), or under dense pects its newest UHF Follow- is not business as usual. Rather, JV2010
jungle foliage. On (UHF F/O) satellite constellation to translates to a more dispersed, mobile
Since most U.S. Navy surface ships start to show its age. and agile fighting force with greater de-
have communications systems that pro- Although the degraded health of the mands on SATCOM services. Thus,
vide greater capabilities than current UHF Follow-On satellite constellation what is needed is a satellite communi-
MSS systems, shipboard use for MSS is several years away, Navy has already cation system better than UHF F/O that
appears limited to search and rescue, initiated work to study when and how helps the warfighter dominate the future
emergency evacuation and disaster re- to replace UHF F/O. In fact, Naval battle. MUOS shall answer that call.
lief operations. Shore units that deploy Space Command, with enthusiastic help The draft MUOS ORD contains op-
personnel to remote locations may have from the joint community, is taking erational performance requirements
greater use for these lightweight termi- steps today to develop the requirements agreed upon by the joint community
nals to provide communications connec- for a replacement system to UHF F/O over a series of meetings held in
tivity when no other means are avail- called the Mobile User Objective Sys- Dahlgren, Va. In time, DoD shall ac-
able. tem (MUOS). quire a system that meets the MUOS
Specifically, Naval Space Command requirements.
Current MSS Picture is leading development of the MUOS
The Department of Defense will con- Operational Requirements Document Fielding System in 2007
tinue to monitor the commercial MSS (ORD). The MUOS ORD shall state to Navy plans to start fielding the Mobile
capabilities for potential usefulness to the material developer and industry what User Objective System in 2007. MUOS
U.S. military forces. For the near future, the Department of Defense requires of shall use technological innovations to
commercial systems (e.g., INMARSAT the new satellite communications sys- service more users and provide a true
and Iridium) will be used to augment tem. "communications-on-the-move" capa-
military satellite communications sys- By regulation, an ORD serves as the bility. No matter what technology is em-
tems. As the commercial sector matures cornerstone document for any DoD pro- ployed, MUOS is required to maintain
and greater capabilities become avail- gram. In this case, the MUOS ORD those positive capabilities associated
able, DoD will explore the possibility contains the future narrowband satellite with the UHF spectrum: communica-
of adapting new commercial systems for communication (SATCOM) operational tions in forested and urban terrain un-
military use. requirements that, when met, will en- der adverse weather conditions.
able Sailors, Marines, soldiers and air- The UHF communications signal is
Author Thomas B. Sanford is a com- men to accomplish their respective mis- able to penetrate a double canopy for-
mercial SA TCOM action officer in
sions during both war and peacetime.
Naval Space Command's Plans (Please see MUOS on page 6)
Division at Dahlgren, Va.
SPACE TRACKS • January 2000
MUOS
(Continued from page 5)
est or heavy rain to reach the satellite Access (DAMA) techniques and equip- vantage of advances in 21st century tech-
and, in turn, complete the link to the ment offer considerable relief from the nology to give the warfighter a far more
other user. With the traditional reliance popularity of UHF SATCOM. Yet, capable narrowband SATCOM system
upon UHF SATCOM, the warfighter MUOS takes the solution a step further than UHF F/O. At the same time,
has grown accustomed to communicat- by providing a capacity amount that is MUOS shall maintain the all-weather
ing in all types of weather in which other able to meet 100 percent of the fore- and harsh operational environment
types of SATCOM may prove unreli- casted demand for UHF in 2010. capability found in the UHF SATCOM
able. Today, the military does not have a system today.
Also, the U.S. military appreciates a true communications-on-the-move UHF Naval Space Command takes its ad-
radio, exemplified by UHF SATCOM, SATCOM terminal for the infantryman. vocacy of Fleet requirements seriously
which functions under all types of com- Presently, a Marine must stop and ori- and shall continue to lead development
bat whether in a heavily forested or ur- ent the antenna on his PSC-5 Spitfire of the MUOS ORD until its final ap-
ban environment. UHF SATCOM manpack terminal to talk on UHF proval.
works in harsh operational environ- SATCOM.
ments and goes where the warfighter Once MUOS is fully fielded, a Author Al Sapp is employed by
fights. The joint community insists that Marine may communicate on his ARINC and supports Naval Space
Command's Plans Division.
MUOS maintain those qualities. handheld terminal while moving to-
wards the objective. This is a dramatic
Fixing Shortfalls change from today's cumbersome Contracts
Yet, MUOS goes beyond simply per- manpack terminals.
petuating the virtues of UHF satellite As the Department of Defense tran- Awarded
communications. MUOS must fix some sitions from the UHF F/O constellation
for MUOS
of the shortfalls of UHF F/O, such as to MUOS, careful consideration must be
insufficient capacity. People know a given to the enormous investment made Studies
good thing when they see it. As a re- by all the services in acquiring UHF ter-
sult, the demand for UHF F/O services minals prior to MUOS fielding. The The Space and Naval Warfare
is oversubscribed by 250 percent. bottom line is that MUOS must support Systems Command awarded
Analysis conducted by Naval Space interoperability between all users no four contracts in November valued
Command shows that the demand for matter what type narrowband SATCOM at $700,000 each for Advanced
UHF type service is expected to in- terminal is in use. Narrowband System/Mobile User
crease. The Demand Assigned Multiple In summary, MUOS shall take ad- Objective System concept studies.
Awards for the concept studies
were made to Hughes Space &
Communications Co. of Los Ange-
les, Lockheed Martin Missiles &
Space of Sunnyvale, Calif.,
Raytheon Systems Company of St.
Petersburg, Fla., and Spectrum
Astro, Inc., of Gilbert, Ariz.
Advanced narrowband commu-
nications technology and the
Navy's Mobile User Objective Sys-
tem (MUOS) will replace the cur-
rent Navy Fleet Satellite Commu-
nications (FLTSATCOM) space-
craft and Ultra-High-Frequency
Follow-On (UHF F/O) communi-
cations satellite constellations over
the next two decades. These space-
craft currently provide narrowband
A critical requirement for the Mobile User Objective System will be to provide tactical satellite communications to
capabilities associated with the UHF spectrum: communications for ground the Defense Department warfighter.
forces operating in forested and urban terrain and under adverse weather
conditions. U.S. Navy Photo
SPACE TRACKS • January 2000
Solar Max
burned into the atmosphere years before
it normally would have.
Naval Space Command Prepares As NASA began to build its first
to Maintain Satellite Tracking Space Shuttle orbiters, the agency de-
veloped plans to use the space shuttle
Through Forecasted Solar Storm
to reboost Skylab. However, it burned
in years before the first orbiter left the
ground.
f^T*
1989 Solar Maximum
The Air Force's 55th Space Weather
Squadron (55 SWXS) is the Department
of Defense's designated lead in forecast-
ing and warning of solar activity.
Through a combination of ground and
space-based sensors, they forecast future
activity and report current and past ac-
By Jonathan P. Boers tivity.
The main gauge of solar activity for
space object tracking is the hourly AP
[••**.:
I-.'.'^«*1 value. Normal solar activity will have
an AP value of 25 or less. Any value
A major "solar storm" is forecast SHF radiowaves from above 25 is considered a solar storm.
spacetrack radars to be On March 13 and 14, 1989, the AP
for Earth early this year. The
bent (or refracted), as value jumped to over 100 for more than
event, also known as "Solar Maxi-
well as slowed some- a day with a high of 388. This caused
mum," can cause serious problems for ra- what from the speed of both the errors in tracking and the in-
light. This causes ran- creased atmospheric drag on all satel-
dar, communications and space systems.
dom errors in bearing lites below 1,000 kilometers.
The sun continuously emits electro- and range data, which decreases the ac- To cope with the storm, two strate-
magnetic energy and electrically curacy in orbit determination. gies were employed. First, since data
charged particles. Sometimes the flow Once the catalog is degraded from from Naval Space Command's space
of particles and energy increases dra- the noisy radar data, the second effect surveillance network, or "Fence," was
matically and will cause disturbances in kicks in. The extra energy deposited in not being identified automatically and
the near-Earth environment. the Earth's upper atmosphere heats the was being placed on the database as "un-
Western sunspot records start with atmosphere, causing it to expand out- known," differential corrections could
the first telescopic observations by ward. Low Earth-orbiting satellites then not be performed to update the orbits.
Galileo in 1611. It was found that the experience denser air and therefore more The normally tight association tol-
number of sunspots follows roughly an drag than expected. erances on the fence were loosened to
11-year cycle, called the Sunspot or This drag decreases the object's al- associate the observations with the sat-
Solar Cycle. Generally, there is a four- titude and increases its orbital speed. ellites. Also, every available orbital ana-
year rise to a Solar Maximum, followed The result is that the satellite will be lyst at NAVSPACECOM pitched in to
by a gradual seven-year decline to a some distance below and ahead of its manually associate the observations that
Solar Minimum. expected position when a ground radar were obtained before the tolerances
The last Solar Max was in July 1989 or optical telescope attempts to locate were relaxed.
and was the third largest on record. The it. The second strategy was to have the
next Solar Max is projected to be in the When this difference becomes large system perform automatic orbital up-
early part of the year 2000. enough, sensors will not track the satel- dates as often as possible. The system
lite at all and the object can no longer being used to process observations in
Chaos in Space Object Catalog be maintained in the catalog. 1989 only updated orbits once per day,
There are two direct effects on the space The loss of the United States' Skylab in a batch mode, under normal condi-
object catalog from high solar activity. space station was caused by solar activ- tions. This was increased to twice and
First of all, the presence of free elec- ity. Geomagnetic activity was so severe,
trons in the ionosphere causes UHF and for such an extended period, that Skylab (Please see Solar Max on page 8)
SPACE TRACKS • January 2000
Solar Storms Have Wide-Ranging
By Lt.Cmdr. Brian K. Baldauf Disrupted Systems
Communications. Many communica-
While the Earth orbits our Sun at tion systems utilize the ionosphere to re-
some 93 million miles dis- flect radio signals over long distances.
tant, our planet, its fragile Ionospheric storms can affect radio
ecosystems and our technologies are communication at all latitudes. Some
nevertheless susceptible to dynamic radio frequencies are absorbed and oth-
Solar Max fluctuations in energy released by the ers are reflected, leading to rapidly fluc-
Sun. tuating signals and unexpected propa-
(Continued from page 7)
Some major terrestrial results of gation paths.
later three times daily until the atmo- solar variations are the aurora, proton TV and commercial radio stations
sphere returned to normal. events, and geomagnetic storms. are little affected by solar activity, but
The space object catalog was recov- The aurora is a dynamic and delicate ground-to-air, ship-to-shore, Voice of
ered and satellite orbits stabilized after visual manifestation of solar-induced America, Radio Free Europe, and ama-
about one week. geomagnetic storms. The solar wind en- teur radio are frequently disrupted.
ergizes electrons and ions in the mag- Radio operators using high frequencies
Prepared for Solar Max 2000 netosphere. These particles usually en- rely upon solar and geomagnetic alerts
The two lessons learned from the 1989 ter Earth's upper atmosphere near the to keep their communication circuits up
storm were not forgotten: loosen toler- polar regions. When the particles strike and running.
ances and update frequently. the molecules of the thin, high atmo- Some military detection or early-
In 1995, Naval Space Command re- sphere, some of them start to glow in warning systems are also affected by
placed its aging computing systems with different colors. solar activity. The Over-the-Horizon
the Naval Mission Processing System Aurorae begin between 60 and 80 Radar bounces signals off the iono-
(NMPS). This system incorporates a degrees latitude. As a storm intensifies, sphere in order to monitor the launch of
new design that changes processing the aurorae spread toward the equator. aircraft and missiles from long dis-
from large batch processing to near real- The aurorae provide pretty displays, but tances. During geomagnetic storms, this
time processing. they are a visible sign of atmospheric system can be severely hampered by
Instead of waiting nearly an entire changes that wreak havoc on techno- radio clutter. Some submarine detec-
day between observation receipt and logical systems. tion systems use the magnetic signatures
orbit update, the NMPS evaluates the Energetic protons can reach Earth of submarines as one input to their lo-
need for correction within seconds of within 30 minutes of a major flare's cating schemes. Geomagnetic storms
receipt. If a correction is needed, it is peak. During such an event, Earth is can mask and distort these signals.
performed minutes later. showered with highly energetic solar Navigation Systems. Systems such
The tolerances for observation asso- particles (primarily protons) released as LORAN and OMEGA are adversely
ciation are database fields and are eas- from the flare site. Some of these par- affected when solar activity disrupts
ily updated and adjusted as needed. ticles spiral down Earth's magnetic field their radio wavelengths.
As of the writing of this article, peaks lines, reaching the upper layers of our The OMEGA system consists of
as high as 293 have been endured with- atmosphere. eight transmitters located throughout the
out major impacts to the system. The One to four days after a flare or erup- world. Airplanes and ships use the very
more frequent orbital updates have tive prominence occurs, a slower cloud low frequency signals from these trans-
proven enough to handle all the storms of solar material and magnetic fields mitters to determine their positions.
so far in this solar cycle. reaches Earth, buffeting the magneto- During solar events and geomagnetic
The near-Earth space environment is sphere and resulting in a geomagnetic storms, the system can give navigators
neither empty nor benign. Solar activ- storm. These storms are extraordinary information that is inaccurate by as
ity can produce some significant and un- variations in Earth's surface magnetic much as several miles.
pleasant impacts on satellites and their field. If navigators are alerted that a pro-
orbits. Through attention to lessons During a geomagnetic storm, por- ton event or geomagnetic storm is in
learned and sound system design, peri- tions of the solar wind's energy is trans- progress, they can switch to a backup
ods of high solar activity can be man- ferred to the magnetosphere, causing system. GPS signals are affected when
aged effectively. Earth's magnetic field to change rapidly solar activity causes sudden variations
in direction and intensity. in the density of the ionosphere.
Author Jonathan P. Boers is a
mission analyst with Naval Space
Command's NAVSPOC Operations
Branch in Dahlgren, Va.
8 SPACE TRACKS • January 2000
Impact on Earth and Space Environment
Satellites. Geomagnetic storms and ticles, primarily electrons, penetrate the Power companies transmit alternating
increased solar ultraviolet emission heat outer covering of a satellite and deposit current to their customers via long trans-
Earth's upper atmosphere, causing it to their charge in its internal parts. If suf- mission lines. The nearly direct currents
expand. The heated air rises, and the ficient charge accumulates in any one induced in these lines from geomagnetic
density at the orbit of satellites up to component, it may attempt to neutral- storms are harmful to electrical trans-
about 1,000 kilometers increases signifi- ize by discharging to other components. mission equipment.
cantly. This results in increased drag This discharge is potentially hazardous On March 13, 1989, in Montreal,
on satellites in space, causing them to to the satellite's electronic systems. Quebec, 6 million people were without
change orbit slightly. commercial electric power for nine
Unless low-Earth-orbit satellites are Radiation Hazards to Humans hours as a result of a huge geomagnetic
routinely boosted to higher orbits, they Intense solar flares release very-high- storm. Some areas in the northeastern
slowly fall, and eventually burn up in energy particles that can be as injurious U.S. and in Sweden also lost power. By
Earth's atmosphere. Skylab is an ex- to humans as the low-energy radiation receiving geomagnetic storm alerts and
ample of a spacecraft re-entering Earth's from nuclear blasts. Earth's atmosphere warnings, power companies can mini-
atmosphere prematurely as a result of and magnetosphere allow adequate pro- mize damage and power outages.
higher-than-expected solar activity. tection for us on the ground, but astro-
As technology has allowed space- nauts in space are subject to potentially Climate
craft components to become smaller, lethal dosages of radiation. The Sun is the heat engine that drives
their miniaturized systems have become The penetration of high-energy par- the circulation of our atmosphere. Al-
increasingly vulnerable to the more en- ticles into living cells, measured as though it has long been assumed to be a
ergetic solar particles. These particles radiation dose, leads to chromosome constant source of energy, recent mea-
can cause physical damage to micro- damage and, potentially, cancer. Large surements of this solar constant have
chips and can change software com- doses can be fatal immediately. shown that the base output of the Sun
mands in satellite computers. Solar proton events can also produce can vary by up to two-tenths of a per-
Another problem for satellite opera- elevated radiation aboard supersonic air- cent over the 11-year solar cycle.
tors is differential charging. During geo- craft flying at high altitudes over the Temporary decreases of up to one-
magnetic storms, the number and energy polar caps. To minimize this risk, rou- half percent have been observed. At-
of electrons and ions increases. When tine forecasts and alerts are sent through mospheric scientists say that this varia-
a satellite travels through this energized the FAA so that a flight in potential dan- tion is significant and that it can modify
environment, the charged particles strik- ger can alter its course and reduce alti- climate over time. Plant growth has
ing the spacecraft cause different por- tude to minimize radiation exposure. been shown to vary over the 11-year
tions of the spacecraft to be differentially sunspot and 22-year magnetic cycles of
charged. Eventually, electrical dis- Electric Power the Sun, as evidenced in tree-ring
charges can arc across spacecraft com- When magnetic fields move about in the records.
ponents, harming and possibly disabling vicinity of a conductor such as a wire, During proton events, many more
them. an electric current is induced into the energetic particles reach Earth's middle
Bulk charging (also called deep conductor. This happens on a grand atmosphere. There they cause molecu-
charging) occurs when energetic par- scale during geomagnetic storms. lar ionization, creating chemicals that
destroy atmospheric ozone and allow in-
creased amounts of harmful solar ultra-
violet radiation to reach Earth's surface.
A solar proton event in 1982 resulted
in a temporary 70-percent decrease in
ozone densities.
Author Lt.Cmdr. Brian Baldauf is the
meteorology and oceanography
officer for Naval Space Command's
Plans Division. He compiled this
article from various sources, includ-
ing the Naval Research Laboratory,
Space Environmental Center, and Air
Sunspot activity roughly follows an 11-year cycle, characterized by a four-year rise
Force Space Command's 55th Space
to a Solar Maximum followed by a seven-year decline to a Solar Minimum. We are
Weather Squadron (SWXS).
entering the peak of Solar Cycle 23 which is forecast in the graph above.
SPACE TRACKS • January 2000
tific satellite. This satellite is tracked
by U.S. Space Command's Space Sur-
veillance Network (SSN) radar sites,
optical sites, and high-precision satel-
lite LASER ranging tracking stations.
After incorporating LASER tracking
data and the full force model SP method,
satellite motion can be predicted to less
than 1 meter. Using SSN data and the
traditional SP method (Mission SP), pre-
diction errors are 200 to 700 meters.
SpeCS (SPK) can process the same
SSN data and generate predictions
within 10 to 100 meters (SPK). This
example represents "best case" since this
satellite is well tracked. Most satellites
are not as well tracked, so the results
are proportionally less accurate.
SP processing produces improved
state vectors and a covariance matrix.
Navy En For the first time, we can send a cus-
tomer a state vector and also quantify
Forecast Potential its accuracy.
Who are some of the potential users
Collisions in Space
of this more accurate data? NASA, as a
partner in the International Space Sta-
By Jonathan P, Boers tion (ISS) program, has documented a
requirement for a SP catalog with cova-
Naval Space Command has main- outside forces great riance for all satellites with perigees
tained a catalog of all known enough to push the sat- (lowest point in the orbit) less than 600
ellite many kilometers kilometers (about 2,100 satellites). No
space objects for almost 40 years.
away from the predicted human spaceflight missions are cur-
How the command does this is about to
ellipse. These forces in- rently planned to go higher than these
take a giant leap forward in sophistication clude atmospheric drag, orbits.
and accuracy. lunar and solar gravity, In addition, the National Reconnais-
irregularities of the sance Office (NRO) stated a need for a
In July 1999, the command's Spe- Earth, ocean tides, sensor biases and complete SP catalog.
cial Perturbations Catalog System several others. GP software attempts to Finally, Naval Space Command is a
(SPeCS) became operational. The near- model these forces, but its computa- potential customer for SP data in the
Earth portion of the resident space ob- tional method is simplified and cannot operation of its space surveillance sen-
ject (RSO) catalog — about 3,500 ob- account for all these factors. sor known as the "Fence," which is com-
jects — is now maintained to a level of The SP method goes to the other posed of a network of space track trans-
accuracy previously possible only for a extreme by modeling as many of these mitters and receivers across the south-
couple of satellites. forces as theory allows, no matter what ern continental United States.
SPeCS will be able to maintain the the computing cost. The traditional SP The Fence will be upgraded in fre-
entire resident space object SP catalog method does not have enough comput- quency and sensitivity over the next sev-
(about 9,500 objects) by mid 2000. ing power available to work more than eral years, significantly increasing the
a few satellites, and compromises were size of the space object catalog. To pro-
More Accurate Catalog made to keep run times at a minimum. cess the increased number of observa-
There are two methods for describing SPeCS uses the latest and most complete tions, more accurate predictions are es-
and predicting satellite orbits: general SP models available, running with sential and only achievable with a sys-
perturbations (GP) and special pertur- enough computing power to process tem that can maintain a SP catalog.
bations (SP). Theoretically all satellites thousands of satellites at SP levels of ac-
travel along elliptical orbits. The GP curacy. Evolution of Parallel Processing
method calculates a best-fit ellipse from To explain the difference in accu- Naval Space Command and the Naval
using radar and optical observations. racy, consider satellite #22076 (com- Research Laboratory (NRL) have inves-
In reality, satellites are affected by mon name "Topex/Poseidon"), a scien- tigated and developed parallel process-
10 SPACE TRACKS • January 2000