Tuesday, January 29, 2013

TDRS-K Offers Upgrade to Vital Communications Net

     TDRS-K Offers Upgrade to Vital Communications Net

NASA 
                                  NASA's Tracking and Data Relay Satellite System will
                                  get an upgrade this week when the agency launches
                                  the first of a new generation of communications
                                  satellite to connect spacecraft to the ground stations
                                  that support them.

                                  A United Launch Alliance Atlas V 401 is due to loft the
                                  TDRS-K spacecraft Wednesday.Jan.30 on a course
                                  to goesynchronous orbit where the spacecraft will have
                                  a wide view of Earth.

TDRS-K Offers Upgrade to Vital Communications Net


TDRS-K Offers Upgrade to Vital Communications Net

Enclosed in its payload fairing, NASA's Tracking and Data Relay Satellite, TDRS-K, is being lifted for placement atop a United Launch Alliance Atlas V rocket at Cape Canaveral Air Force Station's Space Launch Complex 41.

NASA's Tracking and Data Relay Satellite System will get an upgrade this week when the agency launches the first of a new generation of communications satellites to connect spacecraft to the ground stations that support them.

A United Launch Alliance Atlas V 401 is due to loft the TDRS-K spacecraft Wednesday, Jan. 30 on a course to geosynchronous orbit where the spacecraft will have a wide view of Earth.

TDRS-K Offers Upgrade to Vital Communications Net


TDRS-K Offers Upgrade to Vital Communications Net
1.22.13
 
TDRS-K spacecraft in hangarImage above: The TDRS-K spacecraft stands inside a processing hangar in Titusville, Fla., awaiting packaging for launch into orbit 22,300 miles above Earth. Photo credit: NASA/Jim Grossmann
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TDRS-K spacecraft rendering in orbitImage above: An artist concept of the TDRS-K spacecraft in orbit with its assortment of antennas and a pair of solar arrays to provide electricity. Credit: The Boeing Co.
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NASA's Tracking and Data Relay Satellite System, also known as the Space Network, will get an upgrade this month when the agency launches the first of a new generation of communications satellites to connect man of NASA's spacecraft to their control centers and mission data centers.

A United Launch Alliance Atlas V 401 is due to loft the TDRS-K spacecraft Jan. 30 on a course to geosynchronous orbit where the spacecraft will have a wide view of Earth. From that position, the spacecraft will provide communications with NASA's fleet of Earth-orbiting science spacecraft, including the International Space Station and NASA's Hubble Space Telescope.

The advanced spacecraft, known as TDRS, is needed to ensure the communications network is able to provide critical services to user spacecraft in the next decade.

"We have some aging satellites, so we need new spacecraft to go in there and help carry more of the data," said Diana Calero, mission manager for NASA's Launch Services Program, or LSP, based at Kennedy Space Center in Florida.

The processing for this mission included the standard in-depth reviews but also took into account extra engineering sessions to investigate whether the underperformance of an upper stage engine during an earlier, non-NASA launch would occur during the TDRS ascent, said Tim Dunn, NASA launch director. The Centaur upper stage used by the Atlas V uses an engine similar to the one that underperformed during a Delta IV launch last year.

"Our engineers and analysts from the Launch Services Program, working alongside the United Launch Alliance engineers, we've been methodically reviewing data and working very closely on flight clearance for the TDRS-K mission, so that's been our biggest challenge to date," Dunn said.

The TDRS spacecraft is large and looked impressive as it stood with its large steerable antennas folded over top of each other inside a processing hangar at Astrotech in Titusville, Fla. The spacecraft, built by The Boeing Company in El Segundo, Calif., arrived in Florida on Dec. 18 on an Air Force C-17 transport plane. Following testing, fueling and launch preparations, it was positioned inside a two-part payload fairing and taken to Space Launch Complex 41 at Cape Canaveral Air Force Station.

Onboard thrusters will provide the final propulsion to reach geosynchronous orbit following separation from the Centaur upper stage.

"The antennas are furled and they have a certain amount of days that they can stay furled," Calero said. "If they pass that, then the antennas, when they're deployed, they can actually degrade in space and so we have to play close attention to how long they stay furled. So it was really challenging trying to schedule the shipping of the spacecraft with the moving launch date. We're still watching it very closely."

TDRS-K will be the 11th TDRS launched by NASA since it began building the space-borne network in 1983. The most recent spacecraft launched in 2002 on an Atlas IIA.

Orbiting about 22,300 miles above Earth, positioned roughly over Hawaii, TDRS-K will use its antennas to receive and transmit signals from a wide range of spacecraft to Earth in several frequency bands.

Even rockets carrying spacecraft carry TDRS-compatible communications gear and transmit telemetry during ascent through the orbiting network instead of ground stations, an advancement that saves money by not having to field specialized aircraft and ships or maintain a string of remote stations to monitor a launch.

The number of TDRS satellites required to serve NASA's orbiting fleet of scientific spacecraft has grown from the original architecture of two to six to service the requirements of a diverse set of users.

"All the Hubble images come through TDRS, all the video that we see from the space station and the astronauts and the video we saw from the shuttle, it all comes through TDRS, and then we have all the Earth-orbiting satellites, all that data comes through TDRS," said Paul Buchanan, deputy project manager for TDRS.

The communications constellation replaced the ground stations positioned on Earth so NASA could communicate with astronauts in orbit. That system allowed contact only when the spacecraft passed within range of the antennas, however. With TDRS satellites in place, controllers have near-constant contact with spacecraft.

"If you roll back in history maybe 30, 40 years, back in Mercury days and Apollo there were no TDRS satellites for communication so you had outages between the ground stations," Buchanan said. "We didn't want the outages, we wanted continuous (communications), so that's what motivated the desire for the Space Network."

"We've had to decommission two spacecraft in the last few years due to the electronics degradation after 20, 25 years," Buchanan said. "We're launching now for an immediate need and replenishment schedule."

When their service life is up, the TDRS satellites are boosted about 250 miles higher into what's called a disposal orbit.

 
 
Steven Siceloff,
NASA's John F. Kennedy Space Center
 

NASA Remembers Apollo 1, Challenger, Columbia

NASA Remembers Apollo 1, Challenger, Columbia

Day of Remembrance 2013

Each year, we honor the Apollo 1, Challenger and Columbia crews, as well as other members of the NASA family who lost their lives supporting NASA's mission of exploration.

This year's Day of Remembrance is Friday, Feb. 1, the 10th anniversary of the loss of Columbia.

Mars Rover Curiosity Prepares for Drilling


Mars Rover Curiosity Prepares for Drilling

Curiosity's drill is positioned on a target on a patch of flat, veined rock called

Curiosity has placed its drill onto a series of four locations on a Martian rock and pressed down on it with the rover's arm, in preparation for using the drill in coming days.

This "pre-load" testing enables engineers to check whether the amount of force applied to the hardware matches predictions for what would result from the commanded motions.

Curiosity Maneuver Prepares for Drilling


Curiosity Maneuver Prepares for Drilling
01.28.13
 
Curiosity's drill in place for load testingThe percussion drill in the turret of tools at the end of the robotic arm of NASA's Mars rover Curiosity has been positioned in contact with the rock surface in this image from the rover's front Hazard-Avoidance Camera (Hazcam). Image credit: NASA/JPL-Caltech › Full image and caption 

Mission status report
PASADENA, Calif. - NASA's Mars rover Curiosity has placed its drill onto a series of four locations on a Martian rock and pressed down on it with the rover's arm, in preparation for using the drill in coming days.
The rover carried out this "pre-load" testing on Mars yesterday (Jan. 27). The tests enable engineers to check whether the amount of force applied to the hardware matches predictions for what would result from the commanded motions.
The next step is an overnight pre-load test, to gain assurance that the large temperature change from day to night at the rover's location does not add excessively to stress on the arm while it is pressing on the drill. At Curiosity's work site in Gale Crater, air temperature plunges from about 32 degrees Fahrenheit (zero degrees Celsius) in the afternoon to minus 85 degrees Fahrenheit (minus 65 degrees Celsius) overnight. Over this temperature swing, this large rover's arm, chassis and mobility system grow and shrink by about a tenth of an inch (about 2.4 millimeters), a little more than the thickness of a U.S. quarter-dollar coin.
The rover team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., sent the rover commands yesterday to begin the overnight pre-load test today (Monday).
"We don't plan on leaving the drill in a rock overnight once we start drilling, but in case that happens, it is important to know what to expect in terms of stress on the hardware," said JPL's Daniel Limonadi, the lead systems engineer for Curiosity's surface sampling and science system. "This test is done at lower pre-load values than we plan to use during drilling, to let us learn about the temperature effects without putting the hardware at risk."
Remaining preparatory steps will take at least the rest of this week. Some of these steps are hardware checks. Others will evaluate characteristics of the rock material at the selected drilling site on a patch of flat, veined rock called "John Klein."
Limonadi said, "We are proceeding with caution in the approach to Curiosity's first drilling. This is challenging. It will be the first time any robot has drilled into a rock to collect a sample on Mars."
An activity called the "drill-on-rock checkout" will use the hammering action of Curiosity's drill briefly, without rotation of the drill bit, for assurance that the back-and-forth percussion mechanism and associated control system are properly tuned for hitting a rock.
A subsequent activity called "mini-drill" is designed to produce a small ring of tailings -- powder resulting from drilling -- on the surface of the rock while penetrating less than eight-tenths of an inch (2 centimeters). This activity will not go deep enough to push rock powder into the drill's sample-gathering chamber. Limonadi said, "The purpose is to see whether the tailings are behaving the way we expect. Do they look like dry powder? That's what we want to confirm."
The rover team's activities this week are affected by the difference between Mars time and Earth time. To compensate for this, the team develops commands based on rover activities from two sols earlier. So, for example, the mini-drill activity cannot occur sooner than two sols after the drill-on-rock checkout.
Each Martian sol lasts about 40 minutes longer than a 24-hour Earth day. By mid-February, the afternoon at Gale Crater, when Curiosity transmits information about results from the sol, will again be falling early enough in the California day for the rover team to plan each sol based on the previous sol's results.
NASA's Mars Science Laboratory Project is using Curiosity to assess whether areas inside Gale Crater ever offered a habitable environment for microbes. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate in Washington.
More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity .
 
 
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

2013-036