Phoenix Mars Lander Prepare To Land On Mars!

Mark on your diary because three Mars spacecraft are adjusting their orbits to be over the right place at the right time to listen to NASA's Phoenix Mars Lander as it enters the Martian atmosphere on May 25.

Every landing on Mars is difficult. Having three orbiters track Phoenix as it streaks through Mars' atmosphere will set a new standard for coverage of critical events during a robotic landing. The data stream from Phoenix will be relayed to Earth throughout the spacecraft's entry, descent and landing events. If all goes well, the flow of information will continue for one minute after touchdown.

"We will have diagnostic information from the top of the atmosphere to the ground that will give us insight into the landing sequence," said David Spencer of NASA's Jet Propulsion Laboratory, Pasadena, Calif., deputy project manager for the Phoenix Mars Lander project. This information would be valuable in the event of a problem with the landing and has the potential to benefit the design of future landers.

Bob Mase, mission manager at JPL for NASA's Mars Odyssey orbiter, said, "We have been precisely managing the trajectory to position Odyssey overhead when Phoenix arrives, to ensure we are ready for communications. Without those adjustments, we would be almost exactly on the opposite side of the planet when Phoenix arrives."

NASA's Mars Reconnaissance Orbiter is making adjustments in bigger increments, with one firing of thrusters on Feb. 6 and at least one more planned in April. The European Space Agency's Mars Express orbiter has also maneuvered to be in place to record transmissions from Phoenix during the landing. Even the NASA rovers Spirit and Opportunity have been aiding preparations, simulating transmissions from Phoenix for tests with the orbiters.

Launched on Aug. 4, 2007, Phoenix will land farther north than any previous mission to Mars, at a site expected to have frozen water mixed with soil just below the surface. The lander will use a robotic arm to put samples of soil and ice into laboratory instruments. One goal is to study whether the site has ever had conditions favorable for supporting microbial life.

Phoenix will hit the top of the Martian atmosphere at 5.7 kilometers per second (12,750 miles per hour). In the next seven minutes, it will use heat-shield friction, a parachute, then descent rockets to slow to about 2.4 meters per second (5.4 mph) before landing on three legs.

Odyssey will tilt from its normally downward-looking orientation to turn its ultrahigh-frequency (UHF) antenna toward the descending Phoenix. As Odyssey receives a stream of information from Phoenix, it will immediately relay the stream to Earth with a more capable high-gain antenna. The other two orbiters, Mars Reconnaissance Orbiter and Mars Express, will record transmissions from Phoenix during the descent, as backup to ensure that all data is captured, then transmit the whole files to Earth after the landing. "We will begin recording about 10 minutes before the landing," said JPL's Ben Jai, mission manager for Mars Reconnaissance Orbiter.

The orbiters' advance support for the Phoenix mission also includes examination of potential landing sites, which is continuing. After landing, the support will include relaying communication between Phoenix and Earth during the three months that Phoenix is scheduled to operate on the surface. Additionally, NASA and European Space Agency ground stations are performing measurements to determine the trajectory of Phoenix with high precision.

With about 160 million kilometers (100 million miles) still to fly as of late February, Phoenix continues to carry out testing and other preparations of its instruments. The pressure and temperature sensors of the meteorological station provided by the Canadian Space Agency were calibrated Feb. 27 for the final time before landing. "The spacecraft has been behaving so well that we have been able to focus much of the team's attention on preparations for landing and surface operations," Spencer said.

The Phoenix mission is led by Peter Smith of the University of Arizona, Tucson, with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions are provided by the Canadian Space Agency; the University of Neuchatel, Switzerland; the universities of Copenhagen and Aarhus, Denmark; the Max Planck Institute, Germany; and the Finnish Meteorological Institute. Additional information on Phoenix is online at http://www.nasa.gov/phoenix and http://phoenix.lpl.arizona.edu . JPL, a division of the California Institute of Technology in Pasadena, manages Mars Odyssey and Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Additional information on NASA's Mars program is online at http://www.nasa.gov/mars .

Possible Landing for Phoenix

Launch date makes a difference in the orientation of ellipses marking where NASA's Phoenix Mars Lander will have a high probability of landing, given the planned targeting for the spring 2008 landing site. This map shows possible landing ellipses for the Aug. 3, 2007, opening of the launch period (the ellipse oriented northwest to southeast) and for launch dates at the middle and end of the three-week period of launch opportunities.

The map also shows a color-coded interpretation of geomorphic units -- categories based on the surface textures and contours. The yellow-coded area surrounding a crater informally named "Heimdall" appears to have even fewer boulders on the surface than other units.

The geomorphic mapping is overlaid on a shaded relief map based on data from the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. The red box indicates the location of an image RA4-CTX from the Context Camera on NASA's Mars Reconnaissance Orbiter.

source : http://www.nasa.com

How The Space Shuttle Countdown Operates?

Here are some of the key events that take place at each milestone after
the countdown begins.
Note: Event times and lengths are approximate and subject to change.

T-43 hours and counting The Shuttle Test Director performs the traditional call to stations and the countdown clock is activated.

Begin final vehicle and facility close-outs for launch Check out backup flight systems Review flight software stored in mass memory units and display systems Load backup flight system software into the orbiter's general purpose computers Remove middeck and flight deck platforms Activate and test navigational systems Complete preparation to load power reactant storage and distribution system Complete flight deck preliminary inspections

T-27 hours and holding This is the first built-in hold and typically lasts four hours.

Clear launch pad of all non-essential personnel

T-27 hours and counting

Begin operations to load cryogenic reactants into the orbiter's fuel cell storage tanks

T-19 hours and holding This built-in hold typically lasts four hours.

Demate the orbiter's midbody umbilical unit

T-19 hours and counting

Begin final preparations of the orbiter's three main engines for main propellant tanking and flight Fill launch pad sound suppression system water tank Resume orbiter and ground support equipment close-outs Close out the tail service masts on the mobile launcher platform

T-11 hours and holding This built-in hold varies in length, but typically lasts 12 to 13 hours.

Flight crew equipment late stow Move rotating service structure to "park" position Activate the orbiter's inertial measurement units and communications systems Perform ascent switch list T-11 hours and counting Activate the orbiter's fuel cells Clear the blast danger area of all nonessential personnel Switch the orbiter's purge air to gaseous nitrogen T-6 hours and holding This built-in hold typically lasts two hours. Launch team verifies no violations of launch commit criteria before loading the external tank with propellants Clear pad of all personnel Chill-down of propellant transfer lines Begin loading the external tank with about 500,000 gallons of cryogenic propellants T-6 hours and counting Finish filling the external tank with its flight load of liquid hydrogen and liquid oxygen propellants T-3 hours and holding This built-in hold typically lasts two hours. Perform inertial measurement unit preflight calibration Align Merritt Island Launch Area (MILA) tracking antennas Final Inspection Team proceeds to the launch pad to conduct a detailed analysis of the vehicle as the team walks up and down the entire launch tower Closeout Crew proceeds to the launch pad to configure the crew module for countdown and launch and assist the astronauts with entry into the orbiter T-3 hours and counting Crew departs for the launch pad and, upon arriving at the pad, begins entry into the orbiter via the White Room Complete close-out preparations in the launch pad's White Room Check cockpit switch configurations Astronauts perform air-to-ground voice checks with Launch Control (Kennedy Space Center) and Mission Control (Johnson Space Center) Close the orbiter's crew hatch and check for leaks Complete White Room close-out Close-out crew retreats to fallback area T-20 minutes and holding This built-in hold typically lasts 10 minutes. Shuttle Test Director conducts final launch team briefings Complete inertial measurement unit preflight alignments

T-20 minutes and counting

Transition the orbiter's onboard computers to launch configuration Start fuel cell thermal conditioning Close orbiter cabin vent valves Transition backup flight system to launch configuration

T-9 minutes and holding This is the final built-in hold, and varies in length depending on the mission.

The Launch Director, Mission Management Team Shuttle Test Director poll their teams for a go/no go for launch T-9 minutes and counting Start automatic ground launch sequencer Retract orbiter access arm (T-7 minutes, 30 seconds) Start auxiliary power units (T-5 minutes, 0 seconds) Arm solid rocket booster range safety safe and arm devices (T-5 minutes, 0 seconds) Start orbiter aerosurface profile test, followed by main engine gimbal profile test (T-3 minutes, 55 seconds) Retract gaseous oxygen vent arm, or "beanie cap" (T-2 minutes, 55 seconds) Crew members close and lock their visors (T-2 minutes, 0 seconds) Orbiter transfers from ground to internal power (T-50 seconds) Ground launch sequencer is go for auto sequence start (T-31 seconds) Activate launch pad sound suppression system (T-16 seconds) Activate main engine hydrogen burnoff system (T-10 seconds) Main engine start (T-6.6 second T-0 Solid rocket booster ignition and liftoff! source : http://www.nasa.com

Space Shuttle Endeavour Lifts Off!

Brilliantly lighting up the dark sky, space shuttle Endeavour roared off Launch Pad 39A at 2:28 a.m. EDT Tuesday carrying the STS-123 crew, a module of Japan's Kibo laboratory and a Canadian robotic system to begin the 25th mission to the International Space Station.Brilliantly lighting up the dark sky, space shuttle Endeavour roared off Launch Pad 39A at 2:28 a.m. EDT Tuesday carrying the STS-123 crew, a module of Japan's Kibo laboratory and a Canadian robotic system to begin the 25th mission to the International Space Station.

Source : http://www.nasa.com

STS-123 Ready To Launch

After suiting up, the astronauts made their way out of the crew quarters in the Operations and Checkout Building to the cheers and applause from the crowd of well-wishers as they head for the silver Astrovan that will take them to Launch Pad 39A where Endeavour waits.

Already at the launch pad, members of the Closeout Crew are inside Endeavour as they prepare the crew compartment for the astronauts' arrival. This crew helps the astronauts strap into their seats and prepare for launch.

About the Mission

NASA astronaut Dominic Gorie commands a crew of six, including Pilot Gregory H. Johnson and Mission Specialists Rick Linnehan, Robert L. Behnken, Mike Foreman, Garrett Reisman and Japanese astronaut Takao Doi. Johnson, Behnken and Foreman will be making their first spaceflight.

During the 16-day mission, the crew's two prime objectives are to deliver and attach to the International Space Station the first component of Japan's new laboratory called Kibo, as well as Canada's new robotics system, the Special Purpose Dexterous Manipulator, or Dextre. STS-123 is the 25th shuttle mission to the International Space Station.

Expedition 16 Flight Engineer Leopold Eyharts, who arrived at the station aboard Atlantis in February, will return to Earth with the Endeavour crew as Reisman takes his place on the station.

source : http://www.nasa.com

Saturn's Moon Have Rings?

PASADENA, Calif. -- NASA's Cassini spacecraft has found evidence of material orbiting Rhea, Saturn's second largest moon. This is the first time rings may have been found around a moon.

A broad debris disk and at least one ring appear to have been detected by a suite of six instruments on Cassini specifically designed to study the atmospheres and particles around Saturn and its moons.

Artist concept of Rhea's ring

"Until now, only planets were known to have rings, but now Rhea seems to have some family ties to its ringed parent Saturn," said Geraint Jones, a Cassini scientist and lead author on a paper that appears in the March 7 issue of the journal Science. Jones began this work while at the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, and is now at the Mullard Space Science Laboratory, University College, London.

Rhea is roughly 1,500 kilometers (950 miles) in diameter. The apparent debris disk measures several thousand miles from end to end. The particles that make up the disk and any embedded rings probably range from the size of small pebbles to boulders. An additional dust cloud may extend up to 5,900 kilometers (3,000 miles) from the moon's center, almost eight times the radius of Rhea.

"Like finding planets around other stars, and moons around asteroids, these findings are opening a new field of rings around moons," said Norbert Krupp, a scientist with Cassini's Magnetospheric Imaging Instrument from the Max Planck Institute for Solar System Research.

Since the discovery, Cassini scientists have carried out numerical simulations to determine if Rhea can maintain rings. The models show that Rhea's gravity field, in combination with its orbit around Saturn, could allow rings that form to remain in place for a very long time.

The discovery was a result of a Cassini close flyby of Rhea in November 2005, when instruments on the spacecraft observed the environment around the moon. Three instruments sampled dust directly. The existence of some debris was expected because a rain of dust constantly hits Saturn's moons, including Rhea, knocking particles into space around them. Other instruments' observations showed how the moon was interacting with Saturn's magnetosphere, and ruled out the possibility of an atmosphere.

Evidence for a debris disk in addition to this tenuous dust cloud came from a gradual drop on either side of Rhea in the number of electrons detected by two of Cassini's instruments. Material near Rhea appeared to be shielding Cassini from the usual rain of electrons. Cassini's Magnetospheric Imaging Instrument detected sharp, brief drops in electrons on both sides of the moon, suggesting the presence of rings within the disk of debris. The rings of Uranus were found in a similar fashion, by NASA's Kuiper Airborne Observatory in 1977, when light from a star blinked on and off as it passed behind Uranus' rings.

"Seeing almost the same signatures on either side of Rhea was the clincher," added Jones. "After ruling out many other possibilities, we said these are most likely rings. No one was expecting rings around a moon."

One possible explanation for these rings is that they are remnants from an asteroid or comet collision in Rhea's distant past. Such a collision may have pitched large quantities of gas and solid particles around Rhea. Once the gas dissipated, all that remained were the ring particles. Other moons of Saturn, such as Mimas, show evidence of a catastrophic collision that almost tore the moon apart.

"The diversity in our solar system never fails to amaze us," said Candy Hansen, co-author and Cassini scientist on the Ultraviolet Imaging Spectrograph at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Many years ago we thought Saturn was the only planet with rings. Now we may have a moon of Saturn that is a miniature version of its even more elaborately decorated parent."

These ring findings make Rhea a prime candidate for further study. Initial observations by the imaging team when Rhea was near the sun in the sky did not detect dust near the moon remotely. Additional observations are planned to look for the larger particles.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Magnetospheric Imaging Instrument was designed, built and is operated by an international team led by the Applied Physics Laboratory of the Johns Hopkins University, Laurel, Md.

For information on the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .
Source : http://www.nasa.gov/mission_pages/cassini/media/rhea20080306.html

STS-123 : Endeavour Mission Timeline

STS-123 Timeline :

Day 1

• Endeavour launches from NASA's Kennedy Space Center in Florida
• Open Payload Bay Doors
• Power Up Shuttle's Robot Arm

Day 2

• Inspect orbiter's heat shield using robot arm with boom.

Day 3

• Endeavour performs backflip, or Rendezvous Pitch Maneuver
  
• International Space Station crew photographs Endeavour
  
• Endeavour docks to Space Station.

Day 4

• Astronauts Linnehan and Reisman make first spacewalk
• First segment of Japanese Kibo module installed on Station's Harmony node

Day 5

• Astronauts enter Japanese module

Day 6

• Linnehan and Foreman make second spacewalk, working on assembly of two armed Canadian robot, dubbed Dextre
  

Day 7

• Japanese module outfitting
  
• Dextre testing

Day 8

• Linnehan and Behnken make third spacewalk, working on station assembly and maintenance
  

Day 9

• Crew off duty period
• Robotics work with Dextre
  

Day 10

• Crew off duty
• Preparation for fourth spacewalk

Day 11

• Behnken and Foreman make fourth spacewalk, working on space maintenance and testing a shuttle repair method
  

Day 12

• Late inspection of Endeavour''s Heat Shield
  

Day 13

• Behnken and Foreman make fifth spacewalk, storing shuttle's robotic boom on the station to make room for cargo on next shuttle's mission

Day 14

• Final cargo transfers
  
• Join Crews on news conference
  

Day 15

• Endeavour undocks from International Space Station
• Endeavour flies around space station
  

Day 16

• Crew prepares for landing

Day 17

• De-orbit burn
  
• Endeavour lands at Kennedy Space Station, Florida

source : http://www.nasa.com

Endeavour Crews Launch On March 11

The Endeavour crew members continue their training at NASA's Johnson Space Center in Houston, reviewing spacewalking procedures and practicing entry and landing inside the motion-based simulator.

After completion of their pre-launch training for the STS-123 mission, the astronauts will fly in to Kennedy Space Center on Friday at about 9 p.m. EST.

All systems are "go" with the space shuttle that will fly the astronauts, a space station module and a robotics system to the International Space Station on March 11 at 2:28 a.m. EDT.
STS-123 is an international mission combining the expertise and experience of several countries working together to create a working 'home' in space.

The crew will deliver the first section of the Japanese-built Kibo laboratory and the Canadian Space Agency's two-armed robotic system called Dextre.

The flight is commanded by Dominic Gorie with Gregory H. Johnson serving as Pilot. The crew also includes Mission Specialists Rick Linnehan, Robert L. Behnken, Mike Foreman, Garrett Reisman and Japanese astronaut Takao Doi.

Reisman will stay aboard the station, trading places with European Space Agency astronaut Léopold Eyharts, who will return to Earth with the crew of Endeavour.

source : http://www.nasa.com