BY JUSTIN RAY

Follow the countdown and launch of a Boeing Delta 2 rocket with NASA's 2001 Mars Odyssey spacecraft bound for the Red Planet. Reload this page for the very latest on the mission.

MONDAY, JULY 16, 2001

NASA's Mars Odyssey spacecraft has passed the half-way mile marker on its voyage to the Red Planet. It has been 100 days since Odyssey's launch atop a Boeing Delta 2 rocket from Cape Canaveral and 100 days remain until it arrives at Mars.

"Odyssey is now closer to Mars than Earth. The spacecraft is healthy and all systems are looking good," said David A. Spencer, the Odyssey mission manager at NASA's Jet Propulsion Laboratory. "Planning for Mars approach and orbit insertion in October is our primary focus right now."

The navigation team reports the spacecraft is right on course. To date, the Deep Space Network has taken 11 separate measurements using the so-called delta differential one-way range measurement, a technique that uses two ground stations to determine the angular position of the spacecraft relative to the known position of a quasar. The measurements provide the navigation team with an additional source of information, adding confidence to their estimates of the Odyssey flight path.

Today, Odyssey is 45.8 million kilometers (about 28.5 million miles) from Earth and 30 million kilometers (about 19 million miles) from Mars, traveling at a velocity of 26 kilometers per second (58,000 miles per hour) relative to the Sun.

MONDAY, JULY 2, 2001

NASA's 2001 Mars Odyssey spacecraft fine-tuned its flight path for arrival at Mars in October as it performed its second trajectory correction maneuver this morning.

Odyssey fired its thrusters for 23 seconds at 12:30 p.m. EDT, which changed the spacecraft's velocity by 0.9 meters per second (about 2 miles per hour).

"Today's successful trajectory correction maneuver marks the completion of the mission's early cruise phase," said David A. Spencer, mission manager for 2001 Mars Odyssey at NASA's Jet Propulsion Laboratory. "All science payloads have been checked out and are operating well."

The Odyssey flight team, he said, is now turning its focus to preparations for Mars orbit insertion and aerobraking, in which repeated passage through the upper atmosphere of the planet will be used to adjust the spacecraft's orbit.

Last week, the team opened the door on the gamma ray spectrometer, managed by the University of Arizona in Tucson, and started taking data with the gamma sensor head. Initial data indicate that the detector performance is excellent.

Odyssey is currently about 35 million kilometers (about 22 million miles) from Earth and traveling at a speed of about 27 kilometers per second (about 59,800 miles per hour) relative to the Sun.

MONDAY, JUNE 18, 2001

The 2001 Mars Odyssey spacecraft is in excellent health as engineers continue to check out and evaluate the performance of its systems and science instruments during its early cruise phase, NASA says.

Friday morning, June 15, flight controllers successfully conducted a visible imaging calibration test of the thermal emission imaging system by pointing the instrument at a star, Menkent, and taking several pictures. Those data were transmitted to Earth during the weekend. Also last week, engineers began a process of heating the gamma ray spectrometer detector in order to erase radiation damage that has naturally occurred to the detector thus far during cruise. The detector will then be in an optimal state to collect science data once the gamma sensor head door is opened later this month.

Earlier this month, engineers successfully tested the UHF radio system by sending and receiving data via the 46-meter UHF antenna at Stanford University in California. The team is continuing to review the data from those tests and plans to conduct additional tests this week.

The Deep Space Network has taken several measurements using the delta differential one-way range measurement, a technique that uses two ground stations to determine the angular position of the spacecraft relative to the known position of a quasar. The measurements provide the navigation team with an additional source of information, adding confidence to their estimates of the Odyssey flight path.

Currently, Odyssey is 26.6 million kilometers (16.5 million miles) from Earth, traveling at a speed of 27.6 kilometers per second (about 61,900 miles per hour) relative to the Sun.

WEDNESDAY, MAY 23, 2001

NASA's Mars-bound Odyssey space probe tweaked its flight path on Wednesday with the first in a series of planned trajectory correction maneuvers.

Odyssey fired its thrusters for 82 seconds at 1:30 p.m. EDT, changing the craft's velocity by 3.6 meters per second (8.1 miles per hour).

"The maneuver executed as planned, and we are very pleased with the spacecraft performance," said David A. Spencer, mission manager for 2001 Mars Odyssey at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Due to the favorable launch we received, this maneuver was much smaller than planned pre-launch. This will allow us to reach Mars with our propellant tanks nearly full, and we will make good use of the extra fuel."

Meanwhile, the principal investigator for the high energy neutron detector instrument reports the detection of gamma ray bursts, occurring on May 8 and May 17. Comparing these measurements with similar measurements from other spacecraft allows scientists to determine the direction of the burst sources. The high energy neutron detector and the companion neutron spectrometer instrument also detected streams of particles and radiation from enhanced solar activity on May 20.

Odyssey is currently about 14.3 million kilometers (8.9 million miles) from Earth and traveling at a speed of about 29 kilometers per second (about 65,700 miles per hour) relative to the Sun.

THURSDAY, MAY 10, 2001

NASA's 2001 Mars Odyssey space probe tested its high-gain communications antenna on Wednesday, sending and receiving commands. Since launch, the spacecraft has been receiving commands over its low-gain antenna and transmitting signals via its medium-gain antenna. This week's test showed the high-gain antenna is working well, and engineers will begin using that link regularly at the end of the month.

Last Friday, May 4, engineers conducted a thruster calibration test designed to measure the small velocity changes that occur when the spacecraft fires its attitude control thrusters. Navigators report that the test went extremely well and that the data are consistent with performance that was predicted before launch.

Odyssey is currently about 9.5 million kilometers (5.8 million miles) from Earth and traveling at a speed of about 30 kilometers per second (about 67,700 miles per hour) relative to the Sun.

SUNDAY, APRIL 29, 2001

NASA's Mars-bound Odyssey spacecraft suffered a reset of one onboard computer last week, possibly due to a solar flare. Flight controllers at the Jet Propulsion Laboratory say the probe is doing fine, however.

"The spacecraft is in excellent condition and back in its normal operating mode," said David A. Spencer, Odyssey's mission manager at JPL. "We are looking into the possibility that intensified solar activity may have affected data in the on-board memory." The affected data in the computer memory is believed to be the cause of the computer reset that happened Tuesday morning. Preliminary data analysis indicates that a reset of the on-board flight computer caused the entry into "safe mode." The spacecraft returned to normal operations Wednesday morning.

Prior to the safing event on Tuesday, the spacecraft transitioned to its cruise attitude where it points its high-gain antenna toward the Earth. On Monday, the team turned on the Martian radiation environment experiment and Wednesday they turned on the electronics for the gamma ray spectrometer instrument.

The Mars Odyssey mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science. JPL is a division of the California Institute of Technology, Pasadena, Calif. The Odyssey spacecraft was built by Lockheed Martin Astronautics, Denver, Colorado.

THURSDAY, APRIL 19, 2001

NASA's Mars Odyssey spacecraft turned to face planet Earth and the Moon on Thursday to calibrate its Thermal Emission Imaging System (THEMIS). All calibration objectives were met.

Meanwhile, engineers are in the process of redesigning the spacecraft's cruise attitude after they noted temperature readings that were higher than expected on a high-gain antenna gimbal earlier this week. The cruise attitude points the high-gain antenna toward Earth as the spacecraft travels toward Mars.

Next week, the team will turn on the Martian Radiation Environment Experiment (MARIE) and prepare to transition to the new cruise attitude.

Odyssey is currently 3,491,598 kilometers (2,169,574 miles) from Earth and traveling at a speed of 3.3 kilometers per second (7,408 miles per hour) relative to Earth.

THURSDAY, APRIL 12, 2001

NASA has decided to postpone the first trajectory tweaking maneuver by the 2001 Mars Odyssey spacecraft that was envisioned for next Monday, officials announced today.

The probe's flight controllers concluded Odyssey was placed on an acceptable course during launch Saturday aboard a Boeing Delta 2 rocket.

The first in a series of trajectory correction maneuvers will now occur later during the cruise to Mars, NASA says. The navigation team is currently evaluating dates in late May for a potential mid-course correction.

Odyssey, which due to arrive at Mars on October 24, remains in good condition.

Flight controllers will now concentrate on turning on and calibrating the science instruments. On Monday, they will send commands to Odyssey that tell the spacecraft to position itself in its cruise attitude and point both the medium and high gain antennas toward the Earth. On Tuesday, they will turn on the Thermal Infrared Imaging System (THEMIS) and then on Thursday, THEMIS will take both a thermal infrared and a visible image of the Earth.

Odyssey is currently 1,488,556 kilometers (924,944 miles) from Earth and traveling at a speed of 3.3 kilometers per second (7,455 miles per hour) relative to the Earth.

MONDAY, APRIL 9, 2001

When the 2001 Mars Odyssey spacecraft enters orbit around Mars later this year, it will kick off a restructured Mars science program that focuses on the search for water on the Red Planet, past and present. Read our Odyssey science story.

SUNDAY, APRIL 8, 2001

NASA ground controllers report the Mars Odyssey spacecraft is on the planned course and in good condition one day after its successful aboard Delta 2 rocket from Cape Canaveral.

Today the flight team commanded the probe to transition out of a "safe mode" it was in during launch to a normal operating mode. They also turned the spacecraft so that the medium-gain antenna that Odyssey is transmitting over is pointed toward Earth. As of late morning, the team was assessing the state of spacecraft subsystems, and if all is well a command was scheduled to be sent this afternoon to make the transition complete.

Early navigation calculations show that the magnitude of the first trajectory correction maneuver fine-tuning the spacecraft's flight path April 16 will be only 6 meters per second. Because that maneuver will be so small, propellant will be saved for use during Mars orbit insertion, aerobraking and the orbital mission.

Odyssey's signal was first acquired via NASA's Deep Space Network ground station at Canberra, Australia, on Saturday within an hour of liftoff. Since then the mission team has continued to monitor the status of spacecraft subsystems, all of which are performing normally. And ground controllers established a two-way communication link between Mars Odyssey and Earth, enabling the navigation team to start collecting data to assess the spacecraft's flight path.

Among various housekeeping chores Saturday, the team commanded the spacecraft to transmit to Earth at a high rate for playback of data recorded during launch. They also commanded a desaturation of the spacecraft's reaction wheels, a procedure in which the gyro-like devices are spun down in order to remove excess momentum.

The one issue that did arise on Saturday was an alarm triggered by a temperature sensor on Odyssey's solar panel. Officials have looked at the situation and concluded the issue was not a concern.

Saturday afternoon the team switched to a ground station at Santiago, Chile, to communicate with the spacecraft. The project is using Santiago to fill gaps in its Deep Space Network tracking coverage during early cruise.

SATURDAY, APRIL 7, 2001

NASA's 2001 Mars Odyssey spacecraft set sail for the Red Planet on Saturday, departing Earth aboard a Boeing Delta 2 rocket fitted with two video cameras that provided spectacular views of the thunderous blastoff. Read our full story.

1649 GMT (12:49 p.m. EDT)

Mars Odyssey remains in good working order, officials report. The only issue being reported is the one temperature sensor on the solar array that is hotter than the others on the structure. But that does not appear to be a problem.

Over the next few hours the spacecraft will transition out of its launch mode and be placed into a more normal configuration. Controllers will command the probe into its cruise mode tomorrow for the six-month trek to Mars.

The first trajectory correction maneuver to refine the path to Mars is planned for eight days after launch.

We will pause our coverage at this point. Check back later today for a full launch wrap-up story, some pictures and video from the onboard rocketcams.

1611 GMT (12:11 p.m. EDT)

The Mars Odyssey flight control team has been polled after having the chance to examine the data coming back from the spacecraft. The only issue noted was with a temperature measurement on the solar array that was not expected. Engineers are looking at it, but at this point officials don't seem to be too worried.

1607 GMT (12:07 p.m. EDT)

Mars Odyssey's solar array appears to be deployed normally, controllers report. The craft's attitude is as expected.

1600 GMT (12:00 p.m. EDT)

Controllers will spend some time sorting through the data from Odyssey to confirm its status.

1556 GMT (11:56 a.m. EDT)

AOS! Acquistion of signal from Mars Odyssey has occurred as controllers at NASA's Jet Propulsion Laboratory establish contact with the space probe! A round of applause in the control center with the confirmation Odyssey is alive following its launch.

1551 GMT (11:51 a.m. EDT)

The predicted rise of Odyssey over the horizon at Canberra is 11:52:15 a.m. EDT. It could take a bit more time, however, for the station to lock onto the spacecraft as it climbs higher into the sky over Australia.

1550 GMT (11:50 a.m. EDT)

Just a couple of minutes away from establishing contact with Mars Odyssey.

1545 GMT (11:45 a.m. EDT)

The Mars Odyssey spacecraft should be oriented to the proper position in space to communicate with the DSN station in Canberra.

1539 GMT (11:39 a.m. EDT)

NASA Launch Manager Chuck Dovale reports "all indications are the flight went well" during today's mission of the Boeing Delta 2 rocket. Everyone is now awaiting for acquistion of the Mars Odyssey's signal via the Deep Space Network tracking site in Canberra, Australia.

1534 GMT (11:34 a.m. EDT)

T+plus 31 minutes, 48 seconds. SPACECRAFT SEPARATION! NASA's 2001 Mars Odyssey spacecraft has successfully departed Earth for its journey to the Red Planet. The satellite was released from the Delta rocket's third stage following launch today from Cape Canaveral.

In the next few minutes Odyssey's power-generating solar array will be deployed and the radio transmitter will be activated. First signals from the Mars-bound probe are expected about 20 minutes from now.

1532 GMT (11:32 a.m. EDT)

T+plus 30 minutes. Data now being received from the third stage via a tracking station in Oman.

1530 GMT (11:30 a.m. EDT)

T+plus 28 minutes. Now about three minutes away from the scheduled deployment of Mars Odyssey from the third stage.

1529 GMT (11:29 a.m. EDT)

T+plus 27 minutes. The crew aboard the P-3 tracking aircraft was unable to confirm the burn of the third stage.

1528 GMT (11:28 a.m. EDT)

T+plus 26 minutes, 15 seconds. The third stage should have completed its burn by now. But there is a problem getting the live data from the rocket to the Cape. This is not necessarily an indication of a problem with the Delta 2.

1527 GMT (11:27 a.m. EDT)

T+plus 25 minutes. The solid-fueled third stage should be firing at this point. However, the data is too noisy for engineers at Cape Canaveral to confirm ignition.

1526 GMT (11:26 a.m. EDT)

T+plus 24 minutes, 30 seconds. The third stage has spun up and separated from the spent second stage.

1526 GMT (11:26 a.m. EDT)

T+plus 24 minutes. The Delta has passed out of range from Oakhangar. Standing by for data from a P-3 aircraft.

1525 GMT (11:25 a.m. EDT)

T+plus 23 minutes, 21 seconds. SECO 2. Confirmation now received that the second stage has shut down as planned.

1524 GMT (11:24 a.m. EDT)

T+plus 22 minutes, 25 seconds. Second stage engine is now up and firing again. This is a 51-second burn.

1523 GMT (11:23 a.m. EDT)

T+plus 21 minutes. The tracking site in Fucino, Italy has picked up the rocket's signal and beaming back the remarkable onboard camera video.

1521 GMT (11:21 a.m. EDT)

T+plus 19 minutes. Normal roll-control jet activity as the rocket remains n good health during this coast.

1520 GMT (11:20 a.m. EDT)

T+plus 18 minutes. Data now being received again from the Delta 2 rocket. Coming up on second stage engine restart at T+plus 22 minutes, 24 seconds into the flight.

1517 GMT (11:17 a.m. EDT)

T+plus 15 minutes. Nothing much to report at this point. The rocket is out of range from any tracking station as it coasts above the North Atlantic Ocean. The next station to acquire will be the Oakhangar site in England in a few minutes.

1515 GMT (11:15 a.m. EDT)

T+plus 13 minutes. The official launch time was 11:02:21.860 a.m. EDT (1502:21.860 GMT).

1513 GMT (11:13 a.m. EDT)

T+plus 11 minutes. The Delta 2 rocket has passed out of range from the New Hampshire ground station as expected. The Delta rocket is now in a coast period that will last another 11 minutes before the second stage restarts.

1512 GMT (11:12 a.m. EDT)

T+plus 10 minutes, 20 seconds. SECO 1. Confirmation that the second stage engine has cut off as planned and the Delta 2 rocket with Mars Odyssey have arrive in a preliminary orbit around Earth.

1511 GMT (11:11 a.m. EDT)

T+plus 9 minutes, 30 seconds. Altitude 104 miles, downrange distance 1,490 miles, velocity is 17,500 miles per hour.

1511 GMT (11:11 a.m. EDT)

T+plus 9 minutes. Second stage engine continues to fire. Cutoff coming up in about a minute.

1509 GMT (11:09 a.m. EDT)

T+plus 7 minutes, 20 seconds. The Air Force's New Hampshire Tracking Station has acquired the rocket's signal as the Delta 2 flies up the Eastern Coast of the U.S.

1509 GMT (11:09 a.m. EDT)

T+plus 7 minutes. Altitude 95 miles, downrange distance 833 miles, velocity is 15,000 miles per hour.

1508 GMT (11:08 a.m. EDT)

T+plus 5 minutes, 40 seconds. Altitude 84 miles, downrange distance 581 miles, velocity is 14,000 miles per hour.

1507 GMT (11:07 a.m. EDT)

T+plus 5 minutes. The protective payload fairing enclosing the Mars Odyssey spacecraft atop the rocket has separated with no recontact detected.

1507 GMT (11:07 a.m. EDT)

T+plus 4 minutes, 40 seconds. MECO. The first stage main engine cutoff confirmed, the stage has been jettisoned and second stage engine ignition has occurred. Clean separation as Mars Odyssey heads away from Earth.

1506 GMT (11:06 a.m. EDT)

T+plus 4 minutes. The Delta 2 rocket continues climbing into the upper atmosphere and out of the gravity well. First stage main engine producing about 230,000 pounds of thrust.

1505 GMT (11:05 a.m. EDT)

T+plus 3 minutes. First stage engine continues to burn normally. Altitude 40 miles, downrange distance 136 miles, velocity 7,200 miles.

1504 GMT (11:04 a.m. EDT)

T+plus 2 minutes, 20 seconds. The three air-start solid rocket boosters have burned out and separated. The rocket continues its trek to orbit on the power of the first stage liquid-fueled main engine.

1503 GMT (11:03 a.m. EDT)

T+plus 1 minute, 30 seconds. Altitude 12 miles, downrange distance 32 miles, velocity 3,200 miles.

1503 GMT (11:03 a.m. EDT)

T+plus 1 minute, 15 seconds. All six ground-start solid rocket boosters have burned out and separated. The three air-lit solids have ignited.

1503 GMT (11:03 a.m. EDT)

T+plus 60 seconds. Vehicle has passed through maximum dynamic pressure.

1503 GMT (11:03 a.m. EDT)

T+plus 40 seconds. Rocket has passed Mach 1. A smooth flight reported so far.

1502 GMT (11:02 a.m. EDT)

T+plus 20 seconds. Vehicle has rolled to the proper trajectory.

1502:22 GMT (11:02:22 a.m. EDT)

LIFTOFF! Liftoff of NASA's Martian odyssey of 2001 to uncover what the Red Planet is made of. And the Boeing Delta 2 rocket has cleared the tower.

1501:52 GMT (11:01:52 a.m. EDT)

T-minus 30 seconds. Hydraulics and electronics reported go.

The launch ignition sequence will begin at T-minus 2 seconds when a Boeing engineer triggers the engine start switch. The process begins with ignition of the two vernier engines and first stage main engine start. The six ground-start solid rocket motors then light at T-0 for liftoff. At launch, the rocket will produce over 750,000 pounds of thrust.

1501:22 GMT (11:01:22 a.m. EDT)

T-minus 1 minute. The Range has given its final clear-to-launch. The Delta 2 rocket's second stage hydraulic pump has gone to internal power after its pressures were verified acceptable.

1500:52 GMT (11:00:52 a.m. EDT)

T-minus 90 seconds. The launch pad water system is activated. At the telemetry receiving areas where data from the rocket will be transmitted, the data recording charts have gone to high speed as the liftoff nears.

1500:22 GMT (11:00:22 a.m. EDT)

T-minus 2 minutes. The first stage liquid oxygen vents are now being closed so the LOX tank can be pressurized for launch. Puffs of vapor from a relief valve on the rocket will be seen in the remainder of the countdown as the tank pressure stabilizes.

1459:52 GMT (10:59:52 a.m. EDT)

T-minus 2 minutes, 30 seconds. NASA has declared the 2001 Mars Odyssey spacecraft "go" for launch today to begins its six-month trek to the Red Planet. The craft's three science instruments will look for water ice trapped in the Martian crust, map the planet's mineralogy and study the radiation hazards that could pose a threat to future astronauts on a manned expedition.

1459:22 GMT (10:59:22 a.m. EDT)

T-minus 3 minutes. The safety destruct safe and arm devices are being armed.

This will be a 31-minute flight of three-stage Delta 2 rocket. See the timeline for a summary of launch events.

1458:22 GMT (10:58:22 a.m. EDT)

T-minus 4 minutes and counting. Now in the final phase of the countdown as Delta launch vehicle systems begin transferring to internal power. The Mars Odyssey spacecraft has already switched to internal power. All systems are now ready for launch today at 11:02:22 a.m. EDT from pad 17A at Cape Canaveral Air Force Station in Florida.

1457:22 GMT (10:57:22 a.m. EDT)

Now five minutes from launch!

1456 GMT (10:56 a.m. EDT)

NASA Launch Manager Chuck Dovale and Boeing Mission Director Joy Bryant have completed their readiness polls. No problems were reported and the countdown is set to resume as planned in about two minutes.

1454 GMT (10:54 a.m. EDT)

The launch team has been polled by Boeing Launch Conductor George Stout. All parties reported "ready" to resume the countdown for an on-time launch. The team is now receiving a final briefing of procedures.

1452 GMT (10:52 a.m. EDT)

Now 10 minutes away from the scheduled launch of Mars Odyssey.

1450 GMT (10:50 a.m. EDT)

The Delta 2 rocket will head to an orbit inclined 52 degrees to the equator, flying northeast from Cape Canaveral and paralleling the U.S. Eastern Seabord before passing over Europe and the Middle East. See a map of the ground track.

1448 GMT (10:48 a.m. EDT)

T-minus 4 minutes and holding. The countdown has entered the final planned hold point for today's launch attempt. During this planned 10-minute, 22-second hold, officials will poll the various team members behind the scenes, in the "soft blockhouse", Range Operations Control Center and Mission Directors Center. The final "go" for launch will come from Boeing Mission Director Joy Bryant with concurrence from the Boeing launch team, NASA and Air Force.

1446 GMT (10:46 a.m. EDT)

The latest computer program based upon upper level winds have been uploaded to the Delta 2 rocket's guidance computer. The information tells the computer what wind conditions to expect during the climb to orbit today.

And weather in the Cape Canaveral area have been verified "go" for launch.

1444 GMT (10:44 a.m. EDT)

The first stage fuel tank vent is being closed and the tank is being pressurized for launch. And shortly the third stage and spacecraft safe and arm devices will be armed.

1442 GMT (10:42 a.m. EDT)

T-minus 10 minutes and counting. The countdown is heading to T-minus 4 minutes for a 10-minute, 22-second planned hold. Liftoff the Boeing Delta 2 rocket from Cape Canaveral Air Force Station is still slated to occur at 11:02:22 a.m. EDT to propel the Mars Odyssey spacecraft to the Red Planet.

For this launch, the Boeing model 7925-9.5 Delta 2 rocket. The expendable launch vehicle consists of three stages, nine strap-on solid rocket boosters and a 9.5-foot diameter payload fairing. The rocket stands 126 feet tall. See our rocket fact sheet for more.

1439 GMT (10:39 a.m. EDT)

Checks are now under way of the Range Safety command destruct receivers that would be used to destroy the Delta rocket should a problem arise during the launch. A little earlier, the Range completed RF link checks with the rocket.

1437 GMT (10:37 a.m. EDT)

The trickle charge to the Mars Odyssey spacecraft atop the Delta rocket is being stopped, and the satellite is switching to internal power for launch.

1432 GMT (10:32 a.m. EDT)

T-minus 20 minutes and counting. Typically the countdown for a Delta 2 rocket enters a planned hold period at this time. However, officials opted to delete this hold from the Mars Odyssey countdown because later launch opportunities next week feature two liftoff attempts spread so far apart they would violate the constraint on the amount of time liquid oxygen can remain aboard the Delta 2 with the 20-minute hold. So to be consistent, Boeing decided to remove the hold for all launch opportunities of Mars Odyssey. Today is the first day of the 20-day planetary alignment between Earth and Mars for the launch of Odyssey.

Engineers have just completed gimbal checks of the nozzles on the first stage main engine and twin vernier engines and second stage engine. This test is performed to ensure the engines will be able to steer the rocket during launch.

1422 GMT (10:22 a.m. EDT)

T-minus 30 minutes and counting. Countdown clocks continue ticking along for liftoff at 11:02:22 a.m. EDT today. The count will pause for a 10-minute built-in hold at T-minus 4 minutes.

Over the next few minutes, the "slew" or steering checks of the first and second stage engines will be performed and RF link tests between the Range and rocket are scheduled.

1416 GMT (10:16 a.m. EDT)

Launch Weather Officer Joel Tumbiolo just briefed officials on the current conditions and the forecast for liftoff today. All weather rules are within limits with no concerns.

1404 GMT (10:04 a.m. EDT)

The Delta rocket is now fully fueled for launch today to send the Mars Odyssey spacecraft on its way to the Red Planet.

The vehicle's first stage was successfully loaded with RP-1 kerosene fuel and liquid oxygen this morning. The second stage was loaded with its storable nitrogen tetroxide and Aerozine 50 fuels on Wednesday; and the third stage and strap-on booster rockets are solid-propellant.

There are no problems being reported, the weather is excellent, upper level winds are within limits and the countdown continues on schedule for liftoff at 11:02:22 a.m. EDT.

1402 GMT (10:02 a.m. EDT)

The Delta 2 rocket's first stage liquid oxygen tank has been topped off at 100 percent. The tank will be replenished through the remainder of the countdown to replace the liquid oxygen that naturally boils away. It took 23 minutes, 42 seconds to load the LOX tank today, an operation completed at 10:01:55 a.m. EDT.

1358 GMT (9:58 a.m. EDT)

Now 20 minutes into the liquid oxygen tanking. The "rapid load" phase of filling the tank will continue over the next couple of minutes to the 95-percent level before the slower "fine load" begins to reach the 99-percent mark, which is then followed by topping off the tank to 100 percent.

1355 GMT (9:55 a.m. EDT)

The normal layer of thin ice and frost is forming on the bottom half of the Delta 2 rocket's first stage where the liquid oxygen tank is located.

1351 GMT (9:51 a.m. EDT)

George Pace, the Mars Odyssey project manager, reports the spacecraft remains in fine shape and ready for its launch from planet Earth today at 11:02:22 a.m. EDT. In addition, NASA's network of communications stations known as the Deep Space Network is prepared to support and track Mars Odyssey following launch.

1348 GMT (9:48 a.m. EDT)

Loading of liquid oxygen continues. Now 10 minutes into this approximate 25-minute process.

1338 GMT (9:38 a.m. EDT)

Cryogenic liquid oxygen, chilled to Minus-298 degrees F, is now flowing from a storage tank at pad 17A, through plumbing and into the bottom of the Boeing Delta 2 rocket. The LOX will be consumed by the first stage main engine along with RP-1 kerosene loaded aboard the vehicle over the past hour.

The countdown continues to progress on schedule this morning for launch of the Mars Odyssey spacecraft at 11:02:22 a.m. EDT from Cape Canaveral, Florida. There are no major problems being worked by the launch team and the weather conditions are near-perfect today.

1332 GMT (9:32 a.m. EDT)

The launch team has been given a "go" to begin loading liquid oxygen into the Delta 2's first stage, the final step in fueling the three-stage rocket for flight.

1327 GMT (9:27 a.m. EDT)

NASA Launch Manager Chuck Dovale just polled his team for a readiness to begin loading liquid oxygen into the Delta 2 rocket's first stage. He did report there is a radar tracking station that is down, however it is not mandatory for today's launch. There is an alternate station that is currently operating to provide tracking of the rocket during flight.

Also Dovale said there were a couple of minor technical bugs that have been discussed including a first stage battery heater and a third stage control system testing problem. But these are significant concerns for launch today.

1315 GMT (9:15 a.m. EDT)

The launch team has reported to Boeing Launch Conductor George Stout that all procedures relating to first stage fuel loading have been completed. The strandard drain back of residual fuel and valve configuration chores have been performed.

1307 GMT (9:07 a.m. EDT)

The first stage fuel tank of the Boeing Delta 2 rocket has been fully loaded for today's planned 11:02 a.m. EDT liftoff from Cape Canaveral Air Force Station in Florida. The tank was filled with 9,924 gallons of a highly refined kerosene, called RP-1.

The next major task in the countdown will be loading super-cold cryogenic liquid oxygen into the first stage starting at about 9:30 a.m. EDT.

1301 GMT (9:01 a.m. EDT)

Now 15 minutes into the fueling process. The first stage fuel tank has been loaded with 9,000 gallons so far. Flow rate currently 573 gallons per minute. Once the tank is filled with 9,725 gallons, or 98 percent, the "rapid load" valve will be closed and the slower "fine load" phase will top off the tank to 9,924 gallons for launch.

1256 GMT (8:56 a.m. EDT)

About 7,000 gallons of RP-1 has been pumped into the Delta 2's first stage. The launch team has calculated that the tank's full load is 9,924 gallons today.

1256 GMT (8:56 a.m. EDT)

Now 10 minutes into the fueling procedure with over 6,000 gallons of RP-1 propellant aboard the Delta 2 rocket. The flow rate is 598 gallons per minute.

1251 GMT (8:51 a.m. EDT)

Now five minutes into this approximate 20-minute process to load the rocket's first stage with nearly 10,000 gallons of refined kerosene. The tank has been filled with 3,000 gallons thus far. The flow rate is currently 618 gallons per minute as the "rapid load" phase of fueling continues. The rate will be decreased once the tank is 98 percent full.

1246 GMT (8:46 a.m. EDT)

FUELING BEGINS. RP-1 fuel, a refined kerosene, is now being pumped into the first stage of the Boeing Delta 2 rocket as the countdown continues at Cape Canaveral Air Force Station in Florida for liftoff today at 11:02:22 a.m. EDT.

1242 GMT (8:42 a.m. EDT)

Valves are being configured in preparation for flowing about 10,000 gallons of propellant from a storage tank into the Boeing Delta 2 rocket's first stage this morning at Cape Canaveral's pad 17A.

Called RP-1, the highly refined kerosene will be guzzled along with liquid oxygen (to be pumped into the rocket a little later this morning) by the first stage Rocketdyne RS-27A main engine and twin vernier steering thrusters during the initial four-and-a-half-minutes of flight.

1222 GMT (8:22 a.m. EDT)

T-minus 150 minutes and counting. The terminal countdown has begun for the launch of the Boeing Delta 2 rocket carrying NASA's Mars Odyssey spacecraft. Over the next three hours, the launch team will ready the three-stage rocket, payload and ground support systems for the planned 11:02 a.m. EDT (1502 GMT) blastoff from pad 17A at Cape Canaveral Air Force Station in Florida.

With the countdown underway, the Complex 17 area will be cleared of workers as a safety precaution. A warning horn will be sounded at the seaside complex to alert personnel to depart and head back to road blocks.

Upcoming in the next few minutes, launch team members in the Delta Operations Building, or "soft blockhouse", located about eight miles west of the pad will oversee the pressurization of helium and nitrogen storage tanks inside the rocket's first and second stages; and the second stage fuel and oxidizer tanks will be pressurized for launch. In addition, the Delta's onboard guidance computer -- called the Redundant Inertial Flight Control Assembly or RIFCA -- will be turned on and configured for the mission.

The loading of 10,000 gallons of RP-1 fuel into the first stage is scheduled to start in just under 20 minutes from now.

0725 GMT (3:25 a.m. EDT)

The 12-story mobile service tower enclosing the Boeing Delta 2 rocket at Cape Canaveral's pad 17A was retracted a short time ago as activities continue for launch at 11:02 a.m. EDT (1502 GMT) today. The rocket is now exposed for the first time, and powerful floodlights illuminating the vehicle can be seen for miles around.

The metal cocoon-like structure is used to assemble the rocket on the seaside pad and provide weather protection. Rollback of the tower is a major milestone on the road to prepare for launch.

Workers will now get the tower secured into its launch position and configure the pad for liftoff. The Terminal Countdown remains scheduled to begin at 8:22 a.m. EDT.

FRIDAY, APRIL 6, 2001
2330 GMT (7:30 p.m. EDT)

A Boeing Delta 2 rocket is cleared for liftoff Saturday to propel NASA's 2001 Mars Odyssey spacecraft on its interplanetary cruise to the Red Planet.

Officials held their final readiness reviews on Friday and declared all was set for blastoff at precisely 11:02:22 a.m. EDT (1502:22 GMT) from pad 17A at Cape Canaveral Air Force Station in Florida.

Weather forecasters expect perfect conditions for the launch. Air Force Launch Weather Officer Joel Tumbiolo says he will have "the easiest job" during Saturday's countdown with virtually no chance of the Delta's weather criteria being violated.

The launch time forecast calls for a few clouds at 3,000 feet with 1/8ths sky coverage, visibility of 10 miles or better, southeasterly winds from 120 degrees at 10 gusting to 15 knots, a temperature of 80 to 82 degrees F and relative humidity of 60 percent.

Should a problem prevent an on-time liftoff during the day's first instantaneous launch time of 11:02:22 a.m., officials will have a second instant in time to get the Delta 2 airborne -- at 11:32:22 a.m. EDT -- or else wait until Sunday.

The launch must occur at such exact times to ensure Odyssey is sent on the proper trajectory by the Delta 2.

NASA has a 20-day window extending through April 27 with two opportunities each day to launch Odyssey while Earth and Mars are properly aligned.

The three-stage rocket will need about a half-hour to do its job during launch. See our timeline for a description of the events to occur during launch. We also have another timeline showing the slightly different ascent profile should liftoff slip to the day's second launch opportunity.

Odyssey will spend more than six months on its journey to Mars with arrival expected on October 24. It will spend nearly three months aerobraking to reach the optimum circular orbit around the planet. The probe seeks to look for water ice trapped in the Martian crust, map the planet's mineralogy and study the radiation hazards that could pose a threat to future astronauts on a manned expedition.

"For the first time at Mars we will have a spacecraft that is equipped to find evidence for present near-surface water and to map mineral deposits from past water activity," said Dr. Steve Saunders, 2001 Mars Odyssey Project Scientist. "Despite the wealth of information from previous missions, exactly what Mars is made of is not fully known, so this mission will give us a basic understanding about the chemistry and mineralogy of the surface."

"The scientific trajectory of the restructured Mars Exploration Program begins a new era of reconnaissance with the Mars Odyssey orbiter," said Dr. Jim Garvin, the lead scientist for NASA's Mars Exploration Program. "Odyssey will help identify and ultimately target those places on Mars where future rovers and landers must visit to unravel the mysteries of the Red Planet."

Odyssey is America's return to the Red Planet after two back-to-back failures of the Mars Climate Orbiter and Mars Polar Lander probes in 1999. NASA has performed exhaustive reviews of Odyssey to ensure it is free of defects.

"I don't know what more we could do to have a successful Mars mission," said Ed Weiler, NASA's associate administrator for space science. "What we cannot do is prevent bad luck."

Spaceflight Now will provide comprehensive coverage and play-by-play reports of the final countdown and launch on this page throughout the day on Saturday. So stay tuned!

1410 GMT (10:10 a.m. EDT)

Mars Odyssey is just a day away from launch for tis six-month journey to the Red Planet. All systems remain "go" for Saturday's liftoff of the Boeing Delta 2 rocket. The weather forecast is also favorable.

The final readiness test of Mars Odyssey is scheduled for 1 p.m. EDT today. At 7 p.m. tonight the protective covers will be removed from the probe's science instruments and then the access doors on the rocket's nose cone will be sealed for flight.

THURSDAY, APRIL 5, 2001

Today is a day dedicated to buttoning up NASA's 2001 Mars Odyssey spacecraft atop the Delta 2 rocket at Cape Canaveral as activities continue on schedule and without incident for Saturday's planned 11:02:22 a.m. EDT launch.

Engineers on Wednesday successfully loaded the storable propellant into the Delta's second stage.

The weather forecast remains unchanged with less than a five percent chance of violating the launch rules. This is the summary from Launch Weather Officer Joel Tumbiolo today:

Today, a chance of showers, possibly a thunderstorm, and windy onshore conditions will occur as a weak upper disturbance and back door cold front move through the area. Afterwards, surface and upper level high pressure will build back into Florida resulting in benign weather Friday, and into the weekend. Of little or no concern will be for sea breeze induced cumulus clouds that may develop late in the terminal count on Saturday. On a side note, solar activity continues to be monitored.

The launch time forecast calls for a few clouds at 3,000 feet with 1/8ths sky coverage, visibility of 10 miles or better, southeasterly winds from 120 degrees at 10 gusting to 15 knots, a temperature of 80 to 82 degrees F and relative humidity of 60 percent.

Officials will be watching the Sun on Saturday, too, to ensure the increased solar activity does not pose a threat to the rocket's guidance computer. Solar storms are known to upset electronics and disrupt communications and power systems on Earth and in space.

WEDNESDAY, APRIL 4, 2001

Technicians are fueling the Boeing Delta 2 rocket's second stage today at launch pad 17A in preparation for Saturday's mission to send the 2001 Mars Odyssey spacecraft on its trek to the Red Planet.

The rocket stage is being loaded with about 8,700 pounds Aerozine 50 propellant, which is made of 50 percent unsymetrical dimethyl hydrazine and 50 percent hydrazine, and about 4,600 pounds of nitrogen tetroxide oxidizer.

The storable fuel is consumed by the stage's Aerojet AJ10-118K engine in two scheduled firings during launch.

The launch team and officials also held the Mission Dress Rehearsal today for a final tune-up practice run before Saturday's big event.

There are no serious problems being addressed and all remains set for the 11:02:22 a.m. EDT (1502:22 GMT) liftoff from Cape Canaveral Air Force Station in Florida.

The weather forecast remains favorable with less than a five percent chance that cumulus clouds could pose a constraint to launch. Air Force Launch Weather Officer Joel Tumbiolo issued the following summary on Wednesday:

"Changes expected over next 24-36 hours. Upper disturbance and back door cold front will move north to south down Florida Peninsula late Wed into Thurs. A chance of showers, possibly a thunderstorm, and windy onshore conditions will accompany this system. Afterwards, surface and upper level high pressure will build back into Florida resulting in benign weather Friday, and into the weekend. Of very slight concern will be for sea breeze induced cumulus clouds that may develop late in the terminal count on Saturday. On a side note, solar activity continues to be high and is expected to remain high over the next 2 to 3 days. This will be monitored on a real time basis."

The launch time forecast calls for a few clouds at 3,000 feet with 1/8ths sky coverage, visibility of 10 miles or better, southeasterly winds from 120 degrees at 10 gusting to 15 knots, a temperature of 80 to 82 degrees F and relative humidity of 60 percent.

TUESDAY, APRIL 3, 2001

NASA's Mars Odyssey spacecraft is bolted to its rocketship at Cape Canaveral for Saturday's scheduled blastoff on a 286-million mile journey to the Red Planet.

The 1,598-pound Lockheed Martin-built space probe will be launched from planet Earth atop a Boeing Delta 2 rocket. If all goes as planned, liftoff should occur at precisely 11:02:22 a.m. EDT (1502:22 GMT), one of two instantaneous launch times available on Saturday. The second comes exactly 30 minutes later, giving the Delta launch team another chance to get the rocket airborne if weather or a technical problem prevents an on-time liftoff.

Officials held the Flight Readiness Review on Tuesday. No significant problems were identified, which allowed the order to be given to fuel the rocket's second stage with storable propellant on Wednesday as planned.

The rocket to carry Mars Odyssey is the most powerful version of the Delta 2 currently flying. The vehicle has three stages, nine strap-on solid-fueled motors strapped to its base and features a 9.5-foot diameter nose cone. This is what Boeing refers to as the 7925-9.5 rocket configuration.

Assembly of the rocket at Cape Canaveral's pad 17A began on February 26 when the first stage was erected on the launch mount. The nine solids were added over the next few days followed by the second stage.

Mars Odyssey arrived in Florida from its Lockheed Martin factory in Denver on January 4 after a ride aboard an Air Force C-17 cargo airplane. The craft, packaged inside a special container box, was moved on a transport trailer from KSC's Shuttle Landing Facility to the Spacecraft Assembly and Encapsulation Facility 2 (SAEF-2) located in the KSC Industrial Area. While in SAEF-2, two of Mars Odyssey's science instruments and its three-panel solar array were attached and final testing was performed. It was then mounted to the third stage rocket motor on March 24.

Enclosed in a transportation canister, Odyssey and the third stage were moved to the launch pad on March 27 for mating to the rest of the Delta 2. Following final chores to prepare the probe for flight, the two halves of the rocket's nose cone were installed on Monday.

The launch countdown begins just after 8 a.m. EDT on Saturday.

The early weather forecast appears promising with less than a five percent chance conditions would prevent liftoff. Air Force Launch Weather Officer Joel Tumbiolo issued this summary on Tuesday morning:

"Overall benign weather is expected the rest of the week. Weak disturbance and back door cold front may increase cloudiness on Wednesday. However, surface and upper level high pressure will build in and dominate Florida weather into the weekend. Of very slight concern will be for sea breeze induced cumulus clouds that may develop late in the terminal count on Saturday. On a side note, solar activity is currently high and will be monitored on a real time basis."

The launch time forecast calls for a few clouds at 3,000 feet with 1/8ths sky coverage, visibility of 10 miles or better, southeasterly winds 10 gusting to 15 knots, a temperature of 80 to 82 degrees F and relative humidity of 60 percent.

Should the launch slip to Sunday for some reason, with the liftoff times being 10:29:00 and 11:29:00 a.m. EDT, the meteorologists predict similar weather with less than a five percent chance of unfavorable conditions.

The forecast for Monday, when the launch times will be 9:57:36 and 10:57:36 a.m. EDT, calls for less than a 10 percent chance of weather problems.

Spaceflight Now will provide the most extensive coverage of the Mars Odyssey launch with our continuous running updates on this page throughout the countdown and climb to orbit.