On August 3, 2017 the TDRS-M satellite will be launched atop the massive Atlas V rocket at Kennedy Space Center and I will be there in the press stands near the countdown clock to cover the launch for EDN and Planet Analog. The following information will demonstrate why this launch is of vital importance for the future of the space program.
The new Countdown Clock
The new NASA Countdown clock was used for the first time on December 1, 2014 for the Orion first launch on December 4, 2014. The new display is very similar in size to the historic countdown clock, with a screen nearly 26 feet wide by 7 feet high. While not true high-definition, the video resolution will be 1280 x 360. This new countdown clock has a wide-screen capability that utilizes the latest breakthroughs in outdoor LED display technology with streaming video available. (Image courtesy of NASA)
NASA's entire prelaunch program will be available to showcase on the display. In the event that the numbers stop counting down, the viewers will not have to wonder whether it is a built-in hold or a technical glitch with the rocket – they'll know quickly from the images displayed on the screen.
The network that will control the clock was also modernized. The center now uses Global Positioning Satellites GPS) to coordinate timing across the center rather than the timing facility that was housed in the Central Instrumentation Facility CIF) at Kennedy.
The TDRS satellites
The Tracking & Data Relay Satellite (TDRS) began in 1973 at Goddard Space Flight Center and was created to allow NASA to rely less upon international ground stations for space travel. This program created a space communication coverage system that would last for a long time to come and have broad availability for many NASA programs.
Ground station communications worked for the Mercury and Apollo programs, but the problem with ground stations was that the spacecraft was only able to connect with Earth-based antennas for roughly fifteen minutes per connection during set times during orbit. With the implementation of the TDRS program the TDRS space-based satellite network would provide continuous communications as well as increased amounts of data which would be able to reach NASA’s low-Earth-orbit (LEO) missions.
The first satellite launched for the TDRS project, the TDRS-A, was in 1983 on the Space Shuttle Challenger (STS-6). By 1995, the rest of the first-generation TDRS satellites, TDRS-A through G) were all launched and deployed. The TDRS-B was destroyed January 28, 1986 in the Challenger explosion (Rest in peace challenger crew).
The first generation TDRS satellites A through G were in this configuration (Image courtesy of NASA)
The second generation of TDRS satellites (TDRS-H, I, and J) were built in the late 90s into early 2000 by Hughes, which is now Boeing, in El Segundo, CA.
The second generation TDRS satellites H, I, and J were in this configuration (Image courtesy of NASA)
The third-generation contract, in December 2007, was again awarded to Boeing. The main difference between the second and third generation satellites was a change from on-orbit beamforming of the S-band multiple access return services to ground-based beamforming (GBBF) which was actually a return to the first-generation satellite’s architecture.
The third generation TDRS satellites K, L, and M are in this configuration (Image courtesy of NASA)
This third generation of TDRS satellites are functionally identical to the second generation TDRS with one major exception – beamforming. Multiple Access beamforming will be performed on the ground, unlike the second-generation spacecrafts which perform this function on-board. Like the first generation, this will allow for the unscheduled S-band Distributed Antenna System (DAS) to be possible for low data rate use.
The current Tracking and Data Relay Satellite configuration consists of nine in-orbit satellites (four first generation, three second generation and two third generation satellites) distributed to provide near continuous information relay service to missions such as The Hubble Space Telescope (HST) and the International Space Station (ISS).
The final satellite of the third generation TDRS, the TDRS-M will launch on August 3, 2017 atop the massive Atlas V rocket and will ensure the TDRS program’s reliability for the near future for the next 15 years.
Watch EDN and Planet Analog in the coming months before and after the August 3 launch for more in-depth electronics details of the TDRS-M satellite and also the electronics of the Kennedy Space Center.