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Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
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Meet the people whose lives, choices and achievements shaped the journey.
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Moments that changed communities, movements, institutions and the nation.
Wilmington, North Carolina once had a thriving Black middle class and an elected interracial government. In 1898 white supremacists used violence to overthrow that government, kill Black residents and drive many others from the city.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
Space Network (SN) is a NASA program that combines space and ground elements to support spacecraft communications in Earth vicinity. The SN Project Office at Goddard Space Flight Center (GSFC) manages the SN, which consists of:[1]
Tracking and Data Relay Satellite (TDRS) currently consists of first-generation (F1–F7), and second-generation (F8–F10) satellites.
The space segment of the SN consists of up to six operational relay satellites in geosynchronous orbit. These communications satellites are allocated longitudes for relaying forward and return service signals to and from customers, any entity with an Earth-orbiting satellite that has an agreement with SN to use its communications services, for data transfer and tracking. An additional TDRS, F1, provides dedicated support to the National Science Foundation (NSF) through the use of the WSC Alternate Relay Terminal (WART). Additional spare TDRSs may be in geosynchronous orbit.
All first-generation TDRSs (F1–F7, also known as TDRS A–G) carry functionally identical payloads and all second-generation TDRSs (F8–F10, also known as TDRS H–J) carry functionally identical payloads.[citation needed]
A third generation, TDRS K, L, and M were launched between 2013–2017.
The figures identify the pertinent communications components and associated parameters of the orbiting relay platforms.
For spacecraft operating in a low Earth orbit (LEO) 73 km to 3000 km altitude, the SN is capable of providing tracking and data acquisition services over 100% of the spacecraft's orbit.[2] Spacecraft sent to more distant or exotic destinations rely on either Deep Space Network or their own custom, dedicated networks.
The Network Control Center Data System (NCCDS) is an element of the SN ground segment.[3] Collocated with the White Sands Tracking and Data Relay Satellite System, the NCCDS is the operations control facility for the network. It schedules most Space Network elements and supporting elements and provides interfaces for planning, acquisition, control, and status of the Space Network. The NCCDS is the point-of-contact between customers (who have satellites in orbit) and the Space Network for most scheduling and real-time performance. A customer may obtain Space Network support by submitting specific schedule requests to or establishing generic requirements with the NCCDS. The NCCDS translates customers’ requirements into specific TDRS communications and tracking events. Additionally, the NCCDS notifies affected customers of scheduled system outages so that Mission Operation Centers (MOCs) can properly plan mission activities. Upon MOC request, the NCCDS provides operational performance information (such as data presence monitoring indicators and data quality monitoring data) on scheduled services during actual support to determine if conditions exist that will affect data quality.
The NCCDS issues Network Advisory Messages (NAMs) to provide up-to-date information on network conditions and constraints. These messages are accessible via the NCCDS active NAM web site. The Goddard Space Flight Center uses the NAMs as a means of letting customers know of any performance constraints associated with the TDRS spacecraft.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
Space Network (SN) is a NASA program that combines space and ground elements to support spacecraft communications in Earth vicinity. The SN Project Office at Goddard Space Flight Center (GSFC) manages the SN, which consists of: The geosynchronous Tracking and Data Relay Satellites (TDRS), Supporting ground terminal systems, The Bilateration Ranging and Transponder System (BRTS), Merritt Island Launch Annex (MILA) relay, Network Control Center Data System (NCCDS).
The NASA Deep Space Network (DSN) is a worldwide network of spacecraft communication ground segment facilities, located in the United States (California), Spain (Madrid), and Australia (Canberra), that supports NASA's interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the Solar System and the universe, and supports selected Earth-orbiting missions. DSN is part of the NASA Jet Propulsion Laboratory (JPL).
Indian Deep Space Network (IDSN) is a sophisticated telecommunications infrastructure operated by the Indian Space Research Organization (ISRO) to provide telemetry, tracking and command support its interplanetary missions. Located at the Bayalu campus near Bengaluru, Karnataka, the IDSN comprises a network of large antennas capable of communicating with spacecraft at lunar and interplanetary distances. The network operates under the purview of ISRO Telemetry, Tracking and Command Network (ISTRAC) and functions as part of a global network, receiving complementary support from similar networks run by NASA, China, Russia, ESA, and Japan.
The Chinese Deep Space Network (CDSN) is a network of large antennas and communication facilities that are used for radio astronomy, radar observations, and spacecraft missions of China. The CDSN is managed by the China Satellite Launch and Tracking Control Center General (CLTC) of the People's Liberation Army Aerospace Force. The network was first needed for the lunar mission Chang'e 1, and since has been used to support subsequent missions to the Moon and Mars such as Chang'e 5, Tianwen-1, and Tianwen-2 missions. Similar deep space networks are run by the United States, Russia, European countries, Japan, and India.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Shirley Chisholm, elected in 1968.
