History of NASA GSFC Tracking Services

• The U.S. government asks amateur astronomers around the world to volunteer (over 8,000 people signed up to help) to scan the sky as America's first satellites were placed in orbit and to report on the direction the satellite was moving and the time they saw the satellite "rise" over the horizon and then "set".  This information would be used to assist in determining the orbits of America's first satellites.
• The first test of this system was to help the U.S. government in determining the orbit of Sputnik-1 launched by the Soviet Union in late 1957.

• 12 Baker Nunn telescope tracking cameras deployed around the world to track the position of America's first satellites against the night sky.  The information along with the amateur data from Operation Moonwatch was used to determine the orbits of these early satellites.

• The Naval Research Lab establishes a Minitrack "fence" of 10 antenna sites stretching from North to South America to track and receive data from America's first satellites. 
• Minitrack provided contact with Earth orbiting satellites for less than 10% of most orbits (not all orbits could be covered). 
• They used simple VHF (136 Mhz) dipole antennas to support the low data rates from these early satellites. 
• Data was recorded on tapes at the site and shipped back to GSFC for processing - taking weeks to months to arrive for processing. 
• Responsibility for Minitrack was transitioned to NASA after the Agency was formed in 1958.
• Minitrack supported, for example:

  • October 1957 - Sputnik 1 (required some last minute upgrades to Minitrack since Sputnik communicated at a different frequency than planned U.S. satellites it was built to track)

  • February 1958 - Explorer 1

  • March 1958 - Vanguard 1

• Moving beyond Minitrack, GSFC was put in charge of developing an upgraded network to provide ~15% orbit coverage for Earth orbiting robotic satellites
• Beyond upgrading antennas at the Minitrack sites in North and South America, STADAN added new full tracking, telemetry and command sites in North/South America, Africa, Australia, Europe and Asia - creating an initial network of 17 stations (growing to over 20 stations through the 1960s).
• Stations in Alaska and Australia were placed at high latitude locations to better support the need for data capture from polar orbiting weather satellites 
• STADAN stations used arrays (Satan and Scamp) at 136 and 400 MHz and parabolic dish antennas up to 26m in diameter to support higher data rates at VHF, UHF, L-Band & S-Band (2,100 MHz).  It provided communication at distances out to the Moon. 
• Like Minitrack, STADAN was capable of tracking and receiving telemetry from orbiting satellites - but - it was also able to send up commands as the new sophisticated satellites were able to be commanded from Earth.
• Over time the network transitioned from a Minitrack approach where the focus was primarily on tracking satellites to determine their orbit - to a focus on collecting scientific data.
• Control of the STADAN network was centralized at the Network Operations Control Center at GSFC. 

• STADAN supported various satellites - including:
  • April 1, 1960 TIROS-1 (Television Infrared Observation Satellite) was the world's first weather satellite that could send back black and white images of cloud cover to assist in weather forecasting. It also carried on-board tape recorders so that it could store images until it came over a STADAN station where it would then be commanded to dump the images to the ground (it could send back ~1 image per hour). Since TIROS satellites were in equatorial orbits - they could only image the sky in mid-latitude locations.
  • 1964 Nimbus-1 - the first polar orbiting weather satellite -Nimbus used the newer high latitude STADAN sites in Alaska and Australia to send these images to Earth.
  • 1963 Syncom-1 - the world's first geosynchronous communication satellite launched by NASA to test the concept of using "stationary" communication satellite links to transfer data around the world. STADAN showed for the first time that communication could be accomplished with satellites orbiting more than 20,000 miles above the Earth.
  • 1965 Project Relay - used the STADAN to relay television images across the Atlantic and Pacific oceans to the United States through the STADAN sites as a test of commercial TV relay satellite technology
  • 1965 Intelsat-1 "Early Bird" the world's first geosynchronous commercial communication satellite used STADAN to transmit television and telephone data between Europe and the United States (including transmitting television images of Neil Armstrong walking on the Moon in 1969 to viewers around the world).
  • 1966 The first in a series of Orbital Astronomical Observatory (OAO) satellites is launched to provide human's first glimpse at the universe in ultraviolet and x-ray wavelengths - all supported through the STADAN network.

• A number of Minitrack stations are closed as NASA's ability to accurately track satellites makes it less necessary to have ground stations spaced so close together.  Other Minitrack stations are closed due to political instability in the countries where they were located.

• MSFN operations initiated in time to support the initial orbital flights of Mercury astronauts.
• Originally it consisted of 15 (later growing to 23) antenna sites stretching from near the launch site in Merritt Island Florida  across North/South America Africa and Australia.
• It included upgrades to Nascom to allow high rate data (4Kbps) to flow from the MSFN tracking sites back to Mission Control in real-time so that controllers could talk to orbiting astronauts and see real-time video (live video began with Apollo) along with telemetry data on the health of the spacecraft. 
• For example, a 2Kbps undersea cable was laid to Bermuda in 1963, allowing communication between the ground and the astronauts during a critical 25 second window as they launched. 
• The MSFN stations were arranged to ensure that astronauts were never out of contact with the ground for more than 10 minutes at a time as they orbited Earth during Project Mercury.

• The GRARR system was deployed around the world as the first "active" tracking system that sent/received tracking signals to/from satellites out to lunar distances to measure their distance and velocity. 
• Able to measure the position of a satellite orbiting the Moon with an accuracy of +/-75 feet. 
• This capability would be critical to tracking multiple robotic spacecraft in lunar orbit during the preparation for the Apollo lunar landings.

• First test of satellite laser ranging from GSFC - with the Beacon Explorer 22B satellite - yields a tracking accuracy of +/-6 feet.

• GSFC initiates a STADAN automation effort to allow for less manually intensive equipment set-up for satellite contacts as well as equipment upgrades to enable sites to accept higher data rate communications. This automation effort was called the Stations Operations Technical Control (STOC).

• Confidence in the new Gemini space capsule allows the MSFN to relax the requirement for contact time with crews while they orbited from the Mercury requirement of no more than 10 minute gaps at any time to the Gemini requirement of at least 1 contact with the crew every orbit (~90 minutes).
• Increased data rates received at MSFN sites to 50Kbps. 
• High power C-Band radars were added to the MSFN sites to collect tracking data (accurate to +/-6 ft at a distance of 30,000 miles) that could be used in the orbit determination process.

• Expansion of the MSFN to 23 stations with the addition of, Ascension Island, Antigua, Guam, Grand Bahama Island and others, to ensure full coverage of the trajectory path that astronauts would be on when launched and returned from the Moon during the Apollo Program (very different from the orbital missions of Mercury and Gemini).  A number of existing sites were upgraded to enable the tracking of two spacecraft (Apollo command and service module) at lunar distances.
• Unified S-Band (USB):  The USB system was introduced to support the requirement to receive voice, television, telemetry data and tracking data simultaneously using a single combined link while also simultaneously sending commands. This met the needs of modern satellites and the human spaceflight needs of the Apollo Program.

• NTTF at GSFC (Building-25). 
• Laboratories responsible for the development and testing of equipment for the STADAN and MSFN networks and for training the operations personnel that were then deployed around the world to operate the networks.

• Composed of an on-site laboratories as well as truck based compatibility test vans - GSFC establishes the capability to test flight project RF equipment compatibility with the STADAN and MSFN networks and to train network and flight project personnel using advanced simulation capabilities.

• Four ARIA enter service. 
• ARIA used to fly missions over the oceans to fill gaps in the land based MSFN coverage to ensure coverage for decision makers to evaluate Apollo spacecraft while they were in Earth orbit in determine whether or not they were ready to head off to the Moon.

• The first three AIS (named Vanguard, Redstone & Mercury) enter service.
• Each ship had 170 crew members and a number of 30 foot Unified S-Band antennas.
• They were originally used to support Apollo lunar missions during launch and as they re-entered the atmosphere on their return from the Moon.

• Lands on the Moon - images, voice and data return to Earth on a 56Kbps Unified S-Band link through the MSFN
• GSFC receives an Emmy award in 2009 for this Apollo-11 lunar video

• STADAN and MSFN merged after the Apollo-Soyuz mission to create the STDN. 
• STDN reduced the total number of stations available to 18 and upgraded the remaining sites to perform specific functions at higher data rates (128 Kbps for Shuttle support for example), either in support of the upcoming Space Shuttle program - or - in supporting specific types of LEO satellites.

• Compatibility Test Van evaluation of the Shuttle Solid Rocket Motor plume in 1977/78 showed that metallic particles in the plume would inhibit communication with the Merritt Island tracking station during certain phases of the Shuttle ascent.
• A new STDN station is opened at Ponce de Leon, FL to support Shuttle ascent during periods where the Solid Rocket plume would inhibit communication between the Shuttle and the Merritt Island tracking station.
• PDL was first used to support STS-1 in April, 1981.

• TDRS-1 heads to geosynchronous orbit where it will spend the next 27 years as a communication relay satellite.  A failure of the upper stage rocket strands TDRS-1 in a non-nominal orbit.  Recovery and insertion into operational geosynchronous orbit was achieved using the orbit maintenance fuel/thrusters of the TDRS-1 satellite to perform 39 orbiting raising burns - with the STDN provide tracking support during the recovery.
• In September 1983, TDRS-1 supported its first Shuttle mission and provided more communication support for this one mission than the STDN network had provided to the previous 7 Shuttle missions added together.  A single ground terminal at White Sands, NM is used to transfer data to/from TDRS satellites and to ensure their health.
  • Landsat-4 (launched in 1982) immediately started using TDRS-1 for communication since it had been in a dormant state for a number of months after its primary STDN communication system stopped working but it was able to return to operations using a secondary communication system onboard that was designed to communicate in Ku-Band with the new TDRS network at 85 Mbps.

• With a three satellite constellation (two operational satellites and one on-orbit spare) able to provide 100% orbital coverage for satellites above 650 miles in altitude (lower orbits had a small period each orbit where they were not able to communicate with either operational satellite - this was known as the Zone of Exclusion). 
• The STDN was reduced to stations at Wallops Island, VA, Merritt Island and Ponce de Leon, FL and Dakar, Africa.

• TOPEX/Poseidon mission uses NASA's SLR network and GPS to provide precision orbit knowledge that allows the spacecraft to measure the height of the world's oceans with an accuracy of 1 inch.

• Enabling 100% orbit coverage for satellites at any low-Earth-orbit altitude. 
• To accomplish this they moved TDRS-1 to establish a 3-satellite operational configuration (as opposed to the 2-satellite constellation used to this point) as well as adding a new TDRS ground terminal constructed in Guam (since this new satellite was out of view of the primary TDRSS ground terminal in White Sands, NM).  The initial station with limited capability for ZOE closure was placed in Canberra, Australia until a few years later when the Guam Remote Ground Terminal was completed.
• TDRS 1 actually had to be tipped downward to see Canberra-this was not trivial. Also TDRS had quirks- it had to be continuously talked to or it would go into safe hold-so this was a challenge during the drift to new Indian Ocean position.
• The primary driver for this TDRSS network improvement was the failure of the tape recorders on the Gamma Ray Observatory satellite (orbiting at an altitude of 250 miles) which now required constant communication with Earth through the TDRSS network.  But - with this new 3 operational satellite configuration - the Space Shuttle and other LEO missions could now have 100% orbital coverage as required.

• Becomes operational as a second White Sands ground terminal to support the growing TDRSS constellation of 5 satellites and still growing.

• 10m antenna becomes operational for satellites requiring S-Band and X-Band communication at data rates up to ~100Mbps. 
• Initial users include the European Earth Resource Satellite (ERS) and the Canadian RADARSAT.

• The Ground Network adds 8m transportable antennas to its network.  Enabling S-band communication in Alaska
• The FAST satellite (1996) is the first to use the TOTS to downlink at 2.25Mbps data it collects on the northern aurora. SWAS and TOMS-EP become later TOTS users.

• The Ground Network adds 11.3m S-Band/X-Band antennas to improve performance and to support upcoming high rate Earth Sciences missions.
  • August 1996 - Japan launches the ADEOS satellite into a polar, sun synchronous, orbit, to perform comprehensive studies of environmental change - becoming the first customer of the new 11.3m antennas

• Upgrades are completed so that the WSGT architecture now matches the newer STGT architecture.

• After 10 years of dialogue between NASA, ESA (Europe) and NASDA (Japan), the joint NASA/NASDA Tropical Rainfall Measuring Mission (TRMM) lifts off from Tanegashima in Japan.  Because of the work of the Space Network Interoperability Program to establish interoperability between the space communications networks of these three agencies - TRMM becomes the first NASDA satellite that is able to use the TDRSS network for primary communication.

• TDRS-1 begins providing communication support to both the north and south poles - allowing the National Science Foundation to establish a high data rate link for science data returning from outposts at both poles and to enable regular communication with polar researchers.

• Introduction of commercial tracking services to supplement NASA tracking stations supporting Earth-orbiting missions.
• Initial commercial companies include DataLynx with an antenna in Alaska and Universal Space Network with antennas in Alaska and Hawaii.

• TDRS-1 proved helpful during a 1999 medical emergency at the NSF's Antarctic Amundsen-Scott South Pole Station. The satellite's high-speed Internet connectivity allowed personnel to conduct telemedicine conferences. Doctors in the United States aided Dr. Jerri Nelson, who had breast cancer, in performing a self-biopsy and administering chemotherapy.

• NASA's Satellite Laser Ranging Network is used to track the LRO spacecraft as it orbits the Moon.  SLR data provides distance measurements that are accurate to within +/-4 inches.
• A new Near Earth Network 18 meter, S-Band & Ka-Band antenna at White Sands is used to establish the first high rate link to a satellite in lunar orbit (LRO) at 100 Mbps.

• Two new 18 meter S-Band and Ka-Band antennas at White Sands are used to establish a continuous link with the geosynchronous orbiting SDO spacecraft enabling 130 Mbps continuous downlink (1.4 Terra-Bytes/day)

• ALOS spacecraft begins using TDRS services as the first high data rate (240 Mbps) TDRS Ka-Band user.  TDRS support allows ALOS to double the amount of critical Earth Science data that it is able to send to the ground each day.

• TDRS-K launch will be the first of a third generation of TDRSS satellites that will ensure continued high data rate service with 100% orbit coverage for LEO satellites.

• As part of the Lunar Atmosphere and Dust Environment Explorer (LADEE) the LLCD will send back data at over 600 Mbps over an optical link that will stretch from the surface of the Earth to lunar orbit using a 0.5 Watt laser onboard the satellite.
• This technology demonstration will pave the way for future extremely high data rate optical communication systems of the future.