STS-122 Feature Article
February 29, 2008
Sifting The Sands Of Mars
By Sandra Frederick

Mars Photo Credit: NASA

Perhaps one of the most studied bodies in our solar system, Mars is the first of the “external” planets – planets that lie outside of Earth’s orbit. Often called the Red Planet because of its surface color, it is very small and very cold.  

Mars is the last of what scientists refer to as the “terrestrial” planets – small rocky worlds like Earth. Scientists know that like Earth Mars has pole caps that change with the seasons and the surface shows evidence of ancient bodies of water and volcanism. In fact Mount Olympus is the tallest volcano in the Solar System - higher than three Mount Everests put together. We also know the duration of the day is nearly equal to Earth’s  at 24.5 hours compared with Earth’s 24 hour day.  

But, there are differences as well: its mass is one tenth the size of Earth, therefore, the gravity is much less and the temperature fluctuates between 45 degrees in the daytime to nearly –180 degrees below freezing at night.  

Dr. Leslie  Tamppari, co-investigator of the Phoenix mission, believes there is plenty more to uncover about Mars, such as evidence proving life once existed on the planet. "There is still so much we don’t know about Mars,” she said. “Water is a huge mystery and at some time in Mars history, it may have been more like Earth.'' 

NASA agrees and has constructed the Phoenix Mars Lander to help answer these questions. Launch has been set for August 2007 during a window that opens August 3 and extends for 22 days.  At launch time Mars will be 122,000,000 miles from Earth. 

Speeding through the solar system at about 12,000 mph, the spacecraft is scheduled to descend to the surface of the red planet on May 25, 2008 near the Martian Arctic Circle (about the same latitude as Barrow Alaska). At this time the planet will be more 171 million miles from Earth. The mission costs $417 million.  

“When we launch, Mars is closest to Earth, but when we land on its surface, it is the farthest from Earth,” said Edward Sedivy, Phoenix project manager, Lockheed Martin.

 Out of the findings, the big question scientists want answered is whether or not life has existed in other places besides our own planet. 

“We are finding life in places we thought life could never have existed,” Tamppari said. “So this mission is two-fold, we want to understand Mars and its condition and we would like to continue to send life detection experiments to the planet. If we find the answer is yes, we might want to send more missions there.” 

The Phoenix Mars Mission is the first in NASA’s “Scout Program”, an innovative initiative to send a series of small, low cost spacecraft to Mars in-between the larger missions. Phoenix is designed to study the history of water and search for complex organic molecules in the ice-rich soil of the Arctic Circle. 

This is a view of the northern polar region on Mars as seen by the electronic eyes of  NASA's Mars Odyssey Spacecraft. The deep blue and purple areas are believed to indicate the presence of sub-surface water ice. Phoenix will find out for sure. Photo Credit: NASA

UNCOVERING THE MYSTERIES OF HE MARTIAN ARCTIC

Mars is a cold desert planet with no liquid on its surface and has a thin, carbon-dioxide atmosphere. There are no rivers, lakes or oceans. However, discoveries made by the Mars Odyssey Orbiter in 2002 shows large amounts of subsurface water-ice in the northern arctic plains . 

Extensive spacecraft exploration of Mars by NASA has revealed geologic features that lead scientists to believe water once flowed on the red planet. Channels connect high and low areas convincing most scientists that water eroded these channels long ago. Gullies are another geologic feature providing evidence of past liquid water, which is key because all known life forms require it to survive. 

During its mission, Phoenix will look for proof of organics in the samples it gathers as well as search for clues of the history of liquid water that may have existed in the arctic as recently as 100,000 years ago. By digging into the soil and water-ice just below the surface and analyzing the chemistry of it, scientists will better understand the history of the Martian arctic. 

Organics are any materials that contain carbon and hydrogen and other elements such as nitrogen, sulfur and oxygen. If the onboard experiments detect any of these elements it will mean that life on Mars, past or present, is at least possible, Tamppari said.

Such a discovery could also strengthen a 1996 theory by Johnson Space Center and Stanford University scientists, who believe they found evidence of Martian life in a meteorite discovered in Antarctica. 

Recent discoveries also show that life can exist in most extreme conditions and that some bacterial spores lie dormant in the bitterly cold, dry and airless conditions for millions of years and become activated once conditions become more favorable. Scientists believe such dormant microbial colonies may exist in the Martian arctic.  

The spacecraft will also explore the habitability of the Martian environment by using chemical experiments to assess the soil’s composition of life-giving elements, such as carbon, nitrogen, phosphorus and hydrogen. Phoenix will dig into the soil protected from harmful solar radiation, looking for organic life signatures. 

However, instead of roving the hills and craters like previous missions, it will claw down into the icy soil.  

 “The lander is different from the rovers that we have sent up there,” Sedivy said. “The rovers are all about mobility, covering ground and then examining things they found along the way. Phoenix is a laboratory. It is an in depth scientific investigator.” 

THE SPACECRAFT 

 

The Phoenix Mars Lander is seen here undergoing final preparations for flight.  Photo Credit: NASA

As it’s name implies, Phoenix rises out of the ashes of a previous failed Mars Exploration strategy. Back in the year 1999 NASA was employing a Mars Exploration strategy that involved sending a standardized orbiter and lander to the red planet every two years. The first two of these were the Mars Climate Orbiter and the Mars Polar Lander. Both spacecraft were launched to Mars and both spacecraft crashed (all-be-it for different reasons).  The strategy was canceled at once.  

Meanwhile the next two spacecraft were already under construction. These were the Mars Global Surveyor and the Mars Surveyor Lander. It was decided to proceed with launching the orbiter as planed but the lander was mothballed.   

Several years later, when NASA began its “Scout” program, a proposal was made to use the mothballed Mars Surveyor Lander as the core of a new spacecraft that would explore new sub-surface water ice that was discovered by NASA’s Mars Odyssey spacecraft in the Northern Polar region. Once NASA was sold on the idea the spacecraft was fully renovated, fitted with new instruments, and given a new name – Phoenix. Making use of the existing spacecraft as a core for the new one saved taxpayers an estimated $50.000.000.00. 

Although Phoenix inherited parts from the Mars Surveyor the technology and capabilities are much more sophisticated for this mission, Sedivy said.  

The conditions the spacecraft will face once in space present some challenges, Sedivy said. Because at launch it is the closest to the Sun, heat could a problem. However, as it goes further into the solar systems towards it target, extreme coldness becomes an issue. Engineers built heaters all over the spacecraft to help keep it warm during the cold Martian nights. 

“It can get as cold as –180-degrees to –200-degrees F,” Sedivy said. “We also have lithium batteries, which store the solar power from the Sun, but we want to save that power for the experiments, not for powering the spacecraft.” 

Phoenix, with a nearly 8-foot robotic arm to dig three-foot deep trenches into the subsurface layers, has a list of goals to achieve while parked on the North Polar Region of Mars. The landing site – known as “Green Valley” -- was chosen because it has the possibility of 80 percent water-ice by volume within one foot of the surface.  

The exact location where the robotic arm will dig is going to be decided once the lander sits down in the dusty surface. “By design, the robotic arm will be on the north side of the spacecraft as it touches down so it will be in the shade”, Sedivy said. 

“Some of it will depend on what we see (as we land),” Tamppari said. “We think it is shallow, 3 to 4 maybe 6 centimeters deep. We can only sample (the surface) not dig way down into the ground. And, the color variations of the soil will help us decide where we want to get the samples.” 

There will be some tense moments getting Phoenix on the surface because of the possibility of it landing on rocks, which could damage the spacecraft. Scientists with the project spent weeks reviewing photographs and data from the Mars Reconnaissance Orbiter to pick the perfect place to set down.  

“We have images of our intended landing site,” she said. “We know how many rocks are at the site and we feel it is a low rock abundance area. We do our best, but the possibility is, we could get unlucky.” 

A team of scientists from the Jet Propulsion Lab in Pasadena, Calif., will lead the cruise and entry and descent and the landing on Mars and then the mission will shift to a team from the University of Arizona Science Mission Operations facility in Tucson. Lockheed Martin will also help command the spacecraft from Littleton, Colo. 

“We will be talking to Phoenix every day,” Tamppari said. 

However, Phoenix cannot radio directly back to Earth, instead sending all data through the Mars Reconnaissance Orbiter (MRO) currently in orbit around Mars. 

The Phoenix Lander is being sent to the northern region of Mars to measure volatiles, especially water, and complex organic molecules in the arctic plains. The Robotic Arm (RA) is critical to the achievement of these goals and is designed to dig trenches, scoop up soil and water-ice samples, and deliver the samples to the onboard science instruments for detailed chemical and geological analysis. The arm is over 2-m long, and similar in design to a back hoe. Its development includes system engineering, electronics, software, control algorithms, operations user interfaces, mechanical design, and a bio-barrier to keep the RA sterile prior to landing. The Mobility and Robotic Systems Section is primarily responsible for control, operations, and software for all arm usage, as well as system oversight during spacecraft implementation. Photo Credit: NASA/JPL

MISSION OBJECTIVES  

“The time of year was also a consideration”, Tamppari said. The mission needed to be in the Arctic Circle during summer months utilizing the warmth for solar power production.  

“We are going to be at the peak of summer with the most water coming from the north polar cap,” she said “It is just before the start of northern summer, the start of summer solstice”. 

The first objective of the mission is to determine whether it is possible for there to have been life on the planet along with characterizing the climate and geology and preparing for human exploration.  

"Phoenix has been designed to examine the history of the ice by measuring how liquid water has modified the chemistry and mineralogy of the soil," said Peter Smith, the Phoenix principal investigator at the University of Arizona, Tucson.

With some of the most sophisticated and advanced technology ever sent to Mars, the robotic arm on the lander will dig through the soil to the water ice layer underneath, and deliver soil and ice samples to the mission's onboard experiments. Eight such experiments are planned and it will take about three days for the “sniff and bake oven” – the size of an ink cartridge in a ballpoint pen. -- to heat up to the required 1,800-degree F.  

Once a sample is successfully received and sealed in an oven, the temperature is slowly increased at a constant rate, and the power required for heating is carefully and continuously monitored. This process, called scanning calorimetry, shows the transitions from solid to liquid to gas of the different materials in the sample: important information needed by scientists to understand the chemical character of the soil and ice.

As the temperature of the furnace increases up to 1000°C (1800°F), the ice and other volatile materials in the sample are vaporized into a stream of gases. These are called evolved gases and are transported via an inert carrier to a mass spectrometer, a device used to measure the mass and concentrations of specific molecules and atoms in a sample. The mass spectrometer is sensitive to detection levels down to 10 parts per billion, a level that may detect minute quantities of organic molecules potentially existing in the ice and soil

With these precise measurement capabilities, scientists will be able to determine ratios of various isotopes of hydrogen, oxygen, carbon, and nitrogen, providing clues to origin of the volatile molecules, and possibly, biological processes that occurred in the past. 

As the robotic arm digs for ice samples, a camera placed on its 2-foot mast will reveal high-resolution photographs of the landing site’s geology and a “range map” that enables the team to choose an ideal digging location. And a multi-spectral capability will identify local minerals. Another of the five onboard cameras will scan the Martian atmosphere (up to 12.4 miles) obtaining data on formation, duration and movement of clouds, fog and dust plumes. Phoenix will also carry temperature and pressure sensors. 

“For the first time ever, we are flying a surface LIDAR instrument from the Canadian Space Agency,” she said. “It sits on the deck of the spacecraft and shines lasers into the atmosphere and it will tell us how many far away particles there are, how thick and how high they are. We’ve never flown anything like this before.” 

On the instrument deck are the miniature ovens, a mass spectrometer, an atomic force microscope and a "chemistry lab in a box" to analyze the samples. Imaging systems will provide an unprecedented view of Mars as the lander touches down on 12 Aerojet hydrazine-powered rocket engines. As it lowers itself, a parachute will separate at around 1,870 feet, allowing it to ease onto the dry and powdery surface. Moments after touchdown, the spacecraft’s two 6.7-feet in diameter solar arrays will unfurl spreading more than 18-feet.  

Unlike predecessors Spirit and Opportunity – which both scouted the areas they landed on -- Phoenix is a stationary lander. It will stay in the same spot it landed for the duration of the mission. 

As the scientific world watches, the new evidence collected by Phoenix may answer many unanswered questions. But also looking on will be Sedivy, like a proud father, he equates working on the Phoenix mission over the last five years to “raising a child.” 

“It’s our baby,” he said. “We refer to it as a bird that is leaving the nest.  We have treated it with such care, nursed it and have given it all it needs to be successful. Now it is leaving home.” 

INSTRUMENTS

Robotic Arm (RA)-built by the Jet Propulsion Laboratory  The RA is critical to the operations of the Phoenix lander and is designed to dig trenches, scoop up soil and water ice samples, and deliver these samples to the TEGA and MECA instruments for detailed chemical and geological analysis Microscopy, Electrochemistry, and Conductivity Analyzer (MECA)-built by the Jet Propulsion Laboratory MECA is a combination of several scientific instruments including a wet chemistry laboratory, optical and atomic force microscopes, and a thermal and electrical conductivity probe Robotic Arm Camera (RAC)-built by the University of Arizona and Max Planck Institute, Germany The RAC is attached to the Robotic Arm (RA) just above the scoop

Surface Stereo Imager (SSI)-built by the University of Arizona SSI will serve as Phoenix's "eyes" for the mission, providing high-resolution, stereoscopic, panoramic images of the martian arct Thermal and Evolved Gas Analyzer (TEGA)-built by the University of Arizona and University of Texas, Dallas TEGA is a combination high-temperature furnace and mass spectrometer instrument that scientists will use to analyze martian ice and soil samples. Mars Descent Imager (MARDI)-built by Malin Space Science Systems MARDI plays a key science role during Phoenix's descent to the martian arctic

   

Meteorological Station (MET)-built by the Canadian Space Agency Throughout the course of Phoenix surface operations, MET will record the daily weather of the martian northern plains.

 

 DID YOU KNOW: 

  • Mars is the fourth planet from the Sun and the seventh largest.

  • The first spacecraft to visit Mars was Mariner 4 in 1965. Several others followed including Mars 2, the first spacecraft to land on Mars and the two Viking landers in 1976. Ending a long 20-year hiatus, Mars Pathfinder landed successfully on Mars on July 4, 1997. In 2004 the Mars Expedition Rovers "Spirit" and "Opportunity" landed on Mars sending back geologic data and many pictures.

  • Mars' orbit is significantly elliptical.

  • The southern hemisphere of Mars is predominantly ancient cratered highlands somewhat similar to the Moon. In contrast, most of the northern hemisphere consists of plains, which are much younger, lower in elevation and have a much more complex history.

  • Mars is unable to recycle any of this carbon dioxide back into its atmosphere and so cannot sustain a significant greenhouse effect. The surface of Mars is therefore much colder than the Earth would be at that distance from the Sun.

  • Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%). The average pressure on the surface of Mars is only about 7 millibars (less than 1% of Earth's), but it varies greatly with altitude from almost 9 millibars in the deepest basins to about 1 millibar at the top of Olympus Mons. But it is thick enough to support very strong winds and vast dust storms that on occasion engulf the entire planet for months.

  • Early telescopic observations revealed that Mars has permanent ice caps at both poles; they're visible even with a small telescope. We now know that they're composed of water ice and solid carbon dioxide ("dry ice"). The ice caps exhibit a layered structure with alternating layers of ice with varying concentrations of dark dust.

  • A small number of meteorites (the SNC meteorites) are believed to have originated on Mars.

  • When it is in the nighttime sky, Mars is easily visible with the unaided eye. Mars is a difficult but rewarding target for an amateur telescope though only for the three or four months each martian year when it is closest to Earth.

  • Mars has two tiny satellites which orbit very close to the martian surface – Phobos and Deimos.

Here’s a list of Mars' spacecraft:

Phoenix Mars Lander to be launched August 3, 2007
2005 Mars Reconnaissance Orbiter - arrived March 10, 2006 - operating in Mars orbit
2003 Mars Exploration Rovers - Spirit on Mars, softlanded January 4, 2004 (UT) - Opportunity on Mars, soft landed January 25, 2004 (UT) - both operating on Mars surface
Mars Express - arrived December 25, 2003 - operating in Mars orbit
2001 Mars Odyssey - operating in Mars Mapping Orbit
Mars Global Surveyor - operating in orbit since 1997

ABOUT THE BOOSTER

 

 Photo Credit: ULA

 

 

More Interactive Photography
Gale Crator InterActive First look crisp look around Gale Crator This 360-degree, full-resolution panorama from NASA's Curiosity rover shows the area all around...
Endeavour nose gear in OPF InterActive Endeavour nose gear in OPF This was shot from forward and underneath Space Shuttle Endeavour in the Orbiter Processing...
Endeavor engine compartment InterActive Endeavor engine compartment View into the Space Shuttle's engine compartment with the three main engines removed.
Endeavor engine compartment InterActive Endeavor engine compartment View into the Space Shuttle's engine compartment with the three main engines removed.
Endeavour Cargo Bay InterActive Endeavour Cargo Bay This image was shot from the forward end of Space Shuttle Endeavour's cargo ba as it sits in...
Interior view of the Space Shuttle Endeavour forward flight deck. InterActive Interior view of the Space Shuttle Endeavour forward flight deck. Interior view of the Space Shuttle Endeavour aft flight deck.
Endeavour Forward Flight Deck InterActive Endeavour Forward Flight Deck Interior view of the Space Shuttle Endeavour forward flight deck.
Atlas V with Mars Science Laboratory payload InterActive Atlas V with Mars Science Laboratory payload The rover Curiosity will carry the biggest, most advanced suite of instruments for scientific...
Curiosity rover InterActive Curiosity rover NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or...
Curiosity rover InterActive Curiosity rover NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or...
Gravity Recovery and Interior Laboratory InterActive GRAIL The Gravity Recovery and Interior Laboratory mission's primary science objectives will be to...
Atlas V AV-029 InterActive Atlas V AV-029 ULA Atlas V number AV-029 reaches launch pad on August 4th, 2011. In less than 1 day this Atlas...
Atlas V up close InterActive Atlas V up close Get to know the Atlas V up close. Explore the rivets in this 74.62 megapixel image of the Atlas...
JUNO Atlas V InterActive JUNO Atlas V ULA Atlas V with the JUNO probe sitting atop at Cape Canaveral Air Force Station is ready for...
Atlantis at wheels stop on runway 15 InterActive Atlantis on runway Space Shuttle Atlantis returned to Earth in the predawn hours of July 21st, 2011. Marking the...
Atlantis at wheels stop on runway 15 InterActive Atlantis at wheels stop on runway 15 Space Shuttle Atlantis returned to Earth in the predawn hours of July 21st, 2011. Marking the...
Atlantis and tower InterActive Atlantis and tower Space shuttle Atlantis waits to receive payload for the final space shuttle mission STS-135,...
Atlantis payload preparations InterActive Atlantis payload preparations Space shuttle Atlantis at pad 39A. The payload canister can be seen lifted in to position to...
Walk with the astronauts InterActive Walk with the astronauts A view of the 195ft level of the fixed service structure. This where the astronauts arrive at...
Last Space Shuttle prepares for launch InterActive Last Space Shuttle prepares for launch A close in look at space shuttle Atlantis on June 17th. Launch preparations are on going for...
The last space shuttle to be on the launch pad InterActive The last space shuttle to be on the launch pad Space shuttle Atlantis, the last space shuttle to flight begins launch prepartions at pad 39A...
Last space shuttle arrives at launch pad InterActive Last space shuttle arrives at launch pad Space shuttle Atlantis is seen here from the top of the rotating service structure the moring...
The last space shuttle has left the building InterActive The last space shuttle has left the building Space shuttle Atlantis rolls out of the Vehicle Assembly Building for the last time on the...
Space Shuttle Atlantis prepared to rollout to pad   InterActive Space Shuttle Atlantis prepared to rollout to pad Space shuttle Atlantis complete with the solid rocket boosters and external tank that will...
HiRes Atlantis hanging in VAB InterActive HiRes Atlantis hanging in VAB HiRes image of Space Shuttle Atlantis hanging in the Vehical Assembly Building. This shot was...
Atlantis vertical from VAB Level 5 InterActive Atlantis vertical from VAB Level 5 Space Shuttle Atlantis after being lifted into the verticle position before being mated to the...
Atlantis vertical InterActive Atlantis vertical Space Shuttle Atlantis hangs vertical before removing the rear hoist and lifting it for the...
Atlantis rolling vertical InterActive Atlantis rolling vertical Here Space Shuttle Atlantis is almost vertical being positioned to soon be mated to the...
Atlantis hanging in VAB InterActive Atlantis hanging in VAB Space Shuttle Atlantis is seen here hanging about 10 feet above the VAB floor. It has justed...
Endeavour at night InterActive Endeavour at night Space shuttle Endeavour seen here at night as launch preparation continue for the first launch...
Atlantis rolling over to VAB for final mission InterActive Atlantis rolling over to VAB for final mission Space Shuttle Atlantis rolling over the VAB for the last time. Atlantis is scheduled to be the...
Atlantis outside VAB for employee photos InterActive Atlantis outside VAB for employee photos Space shuttle Atlantis, the last space shuttle, pauses during rollover from the OPF to the VAB...
Hi Resolution image of the last space shuttle InterActive Hi Resolution image of the last space shuttle Hi Resolution composit image of the last space shuttle, Atlantis, as it sits atop the transport...
Atlantis in the VAB InterActive Atlantis in the VAB Nice 360 degree view of the VAB with Atlantis being preped for the Lift and Mate procedure
Atlantis on the sled in VAB InterActive Atlantis on the sled in VAB Explore the VAB with Space Shuttle Atlantis on the sled after rollover to the VAB jst before...
Atlantis being attached to sling InterActive Atlantis being attached to sling Full 360 degree panorama from inside the VAB as Space Shuttle Atlantis is attached to the sling...
Endeavour after RSS retraction InterActive Endeavour after RSS retraction Hi-Res image of Space Shuttle Endeavour on the launch pad 39A minutes after the RSS was...
The Mound STS-134 4/29 Attempt InterActive The Mound STS-134 4/29 Attempt This a 360 degree panorama from the mound of the KSC media center. This was the scence about an...
Alpha Magnetic Spectrometer (AMS) InterActive Alpha Magnetic Spectrometer (AMS) The Alpha Magnetic Spectrometer-2, a particle physics detector designed to search for various...
AMS in the SSPF InterActive AMS in the SSPF The Alpha Magnetic Spectrometer-2, a particle physics detector designed to search for various...
Here is Space Shuttle Endeavour just after sunrise InterActive Here is Space Shuttle Endeavour just after sunrise Here is Space Shuttle Endeavour just after sunrise the morning it arrived from the VAB. How...
Endeavour in the VAB InterActive Endeavour in the VAB Space Shuttle Endeavour sitting stacked and ready atop the crawler to rollout the launch pad.
Endeavour in the VAB InterActive Endeavour in the VAB Space Shuttle Endeavour sitting stacked and ready atop the crawler to rollout the launch pad.
Space Shuttle Discovery final towover InterActive Space Shuttle Discovery final towover View of Space Shuttle Discovery 4 hours after returning to Earth for the last time. Discovery...
Space Shuttle Discovery Final Launch InterActive Space Shuttle Discovery Final Launch This a 360 degree panorama taken 3 mile from the launch pad capturing the final lift off of...
Space shuttle Discovery final launch InterActive Space shuttle Discovery final launch This a 360 degree panorama taken 3 mile from the launch pad capturing the final lift off of...
Discovery at Night InterActive Discovery at Night This a panorama of Space Shuttle Discovery shortly after RSS retraction on 11/3/2010 preparing...
GRIP DC-8 Panorama InterActive GRIP DC-8 Panorama Interior of forward section of NASA GRIP aircraft while configured for studding hurricane...
GRIP DC-8 Interior InterActive GRIP DC-8 Interior Interior of forward section of NASA GRIP aircraft while configured for studding hurricane...
NASA GRIP DC-8 InterActive NASA GRIP DC-8 The NASA DC-8 is a four-engine jet transport that has been highly modified to support the...
Endeavour on pad InterActive Endeavour ready for launch HiRes image of Endeavour at Pad 39A
AMS-2 Antimatter Telescope InterActive AMS-2 Antimatter Telescope Explore the SSPF and ESA's Antimatter Telescope. 360 rotating,zoomable Panorama!
Spectacular ultra hi-rez interactive shot of the Space Shuttle Endeavour on the launch pad for the last time InterActive Explore LC-39A !! Spectacular ultra hi-rez interactive shot of the Space Shuttle Endeavour on the launch pad for...