Launched on March 13, 1989, from onboard Space Shuttle Discovery, TDRS-4 operated in geosynchronous (GEO) altitude at more than 22,000 miles above the Atlantic Ocean region. As part of the spacecraft's end-of-mission activities, its orbit was raised above the congested geosynchronous orbit.
An Artist Rendering of TDRS-4.
TDRS-4 was forced to retire after the loss of one of three Nickel-Cadmium (24 cell) batteries and the reduction in storage capacity for the two remaining batteries that power the satellite. Retirement for the satellite consisted of excess fuel depletion, disconnecting batteries, and powering down the Radio Frequency Transmitters and receivers so that the satellite is completely and permanently passive. This ensures the satellite will never interfere with other satellites from the radio frequency perspective.
This is the second retirement from within the fleet of TDRS. The fleet of seven remaining satellites operates through a supporting ground system and together they make up the Space Network (SN). The SN provides highly automated, user-driven services supporting customer spacecraft with tracking and data acquisition. The network supports a varied number of missions, including the International Space Station, Hubble Space Telescope, launch vehicles, and a variety of other science missions. The SN also provided primary communication support to the Space Shuttle Project.
"The Space Network spacecraft engineering and operations teams worked together very effectively to execute a practically flawless decommissioning of an incredible satellite," says Mike Rackley, SN deputy project manager at NASA's Goddard Space Flight Center, Greenbelt, Md. "TDRS-4 made great and important contributions to NASA's human spaceflight and science missions. We will certainly miss her."
This is the second end-of-mission execution for the fleet of aging first generation TDRS spacecraft. TDRS-4's retirement was preceded by TDRS-1, which was decommissioned and raised to its permanent orbit in June 2010.
A total of six first generation spacecraft were successfully placed into orbit from April 1983 through July 1995, of which four are still active. The spacecraft are approaching the end of their operational life span but they are supplemented by three, second-generation spacecraft.
Together they provide customers with global space to ground communication services.
To continue this critical lifeline, NASA has contracted Boeing to build three additional follow-on TDRS spacecraft, replenishing TDRS-1 and TDRS-4, and expanding NASA's communication services. TDRS-K is scheduled for launch in December of this year followed by TDRS-L in 2013 and TDRS-M in 2015.
The SN is managed by GSFC and its primary ground communications facility is located at the White Sands Complex in Las Cruses, NM. The Human Exploration and Operations Mission Directorate and the Space Communications and Navigation Program at NASA Headquarters fund NASA's Space Network.Nicole Hagey and Dewayne Washington
Dewayne Washington | EurekAlert!
Squeezing light at the nanoscale
17.06.2018 | Harvard John A. Paulson School of Engineering and Applied Sciences
The Fraunhofer IAF is a »Landmark in the Land of Ideas«
15.06.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...
Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.
From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
15.06.2018 | Materials Sciences
15.06.2018 | Ecology, The Environment and Conservation
15.06.2018 | Power and Electrical Engineering