Mission Update: Sept. 17, 2001

NASA's 2001 Mars Odyssey spacecraft performed its third trajectory correction maneuver Sept. 16 to fine-tune its flight path for arrival at Mars. Odyssey fired its small thrusters for 12 seconds, which changed the speed and direction of the spacecraft by .45 meters per second (1 mile per hour).

Odyssey will arrive at Mars at 0230 Universal time Oct. 24 (10:30 p.m. ET on Oct. 23). "This was the first maneuver to target our final aim point for Mars orbit insertion," said David A. Spencer, Odyssey's mission manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Early indications are that the maneuver was right on the money."

When the spacecraft has been rotated so that the star camera is no longer shaded, the images from the star camera have been saturated by sunlight. An internal shade within the star camera is supposed to prevent image saturation.

Engineers determined that part of the problem was reflected light from the open door of the gamma ray spectrometer instrument. The door was closed on Aug. 31.

A subsequent checkout of the planned spacecraft orientations for the rest of the mission showed that the star camera should provide valid images during these critical periods.

Also on Aug. 31, the flight team transitioned the spacecraft to a new orientation for the remainder of its cruise. The new orientation is designed to limit the number of times Odyssey needs to fire its small thrusters to de-spin the reaction wheels as they build up momentum.

On Sept. 6, the flight team performed a checkout of the spacecraft telecommunications subsystem for Mars orbit insertion. During the checkout, the spacecraft was turned to the planned orientation for the large burn, and the radio signal from the spacecraft was monitored. All systems performed as expected.

As of Sept. 17, Odyssey was 10.8 million kilometers (6.7 million miles) from Mars, traveling at a speed of 24 kilometers per second (52,700 miles per hour) relative to the Sun.

Mission Update: Aug. 20, 2001

NASA engineers have turned off a radiation experiment aboard the agency's latest probe en route to Mars, after the instrument failed to respond during a data transfer session.

The trouble with the experiment aboard the Mars Odyssey spacecraft came up last week.

"We have limited information on the nature of the problem with the radiation experiment," said David A. Spencer, Odyssey's mission manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "The investigative team will develop a fault tree containing a list of potential causes for the behavior."

Meanwhile, the spacecraft is in good health as it cruises toward its destination -- about 11.5 million miles (18.5 million kilometers) away. Odyssey is designed to enter orbit at Mars on Oct. 23 for a high-resolution mapping mission. Odyssey currently is traveling at 24 kilometers per second (54,600 miles per hour) relative to the Sun.

Following unsuccessful attempts to reset the radiation instrument, Spencer and other project officials decided to study the trouble with the instrument in coming weeks and propose a course of action to recover the instrument following Mars orbit insertion.

The idea is to keep the focus on preparing for Odyssey's entry into orbit around Mars. This moment is crucial for NASA's reputation as the agency has lost two probes at just this point in years past. Mars Climate Orbiter failed to enter orbit in 1999 and Mars Observer was lost before entering orbit in 1993.

Mars orbit insertion is a demanding maneuver that will require a focused team effort over the next few months.

The spacecraft's other science payloads are working as expected. Odyssey's thermal emission imaging system is made up of an infrared imager and a visible camera, and the gamma ray spectrometer instrument package contains a gamma ray sensor, neutron spectrometer and high-energy neutron detector.

Last Friday, the team opened and closed the valves in the spacecraft's main engine to verify that it is working properly prior to Mars arrival. On October 23, the main engine will burn for 24 minutes so the spacecraft will be captured into orbit around the planet.

The Mars Odyssey mission is managed by JPL for NASA. The Odyssey spacecraft was built by Lockheed Martin Astronautics, Denver. NASA's Johnson Space Center in Houston built and manages the Martian radiation environment experiment.

CLICK FOR FULL COVERAGE: MARS ODYSSEY SPECIAL REPORT

Mission Update: July 16, 2001
At 11:30 a.m. Eastern time today, NASA's 2001 Mars Odyssey spacecraft passed the halfway point on its journey to Mars.

It has been 100 days since Odyssey's launch and 100 days remain until it arrives at the red planet.

"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.

As of this morning, Odyssey was 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.

Mission Update: July 5, 2001

The Mars Odyssey spacecraft fine-tuned its flight path for arrival at Mars in October as it performed its second
trajectory correction maneuver on July 2.

Odyssey fired its thrusters for 23 seconds at 9:30 a.m. Pacific time, 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.

As of July 2, Odyssey was 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.

Mission Update: June 18

NASA officials said the 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.

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.

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 distant galaxy. The measurements provide the navigation team with an additional source of information, adding confidence to their estimates of the Odyssey flight path.

As of June 18, Odyssey was 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.

Mars Odyssey On Track and 'Working Very, Very Well'
08 June 2001: "The Odyssey is working very, very well," said spacecraft manager Roger Gibbs. "Hopefully that will continue, and we’re preparing for the next phase of the mission." Full Story

Mission Update: Thursday, May 24, 2001

NASA's 2001 Mars Odyssey spacecraft performed its first trajectory correction maneuver early on May 23 as it fired its thrusters to fine-tune its flight path for arrival at Mars in October.

Odyssey fired its thrusters for 82 seconds at 10:30 a.m. Pacific time, which changed the spacecraft'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.

Spencer said the maneuver was much smaller than had been planned prior to launch, because things went better than expected in the launch.

"This will allow us to reach Mars with our propellant tanks nearly full, and we will make good use of the extra fuel," he said.

In a bit of remote sensing, the high-energy neutron detector instrument aboard the spacecraft detected gamma ray bursts, flashes of intense energy from deep space that reached Odyssey 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, mysterious things that scientists have been puzzling over for years.

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.

As of May 23, Odyssey was 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.

Mission Update: Thursday, May 10, 2001

Flight controllers at the Jet Propulsion Laboratory
successfully tested the ability of Odyssey's high-gain communications antenna to send and receive commands. Since
launch, the spacecraft has been receiving commands over its
low-gain antenna and transmitting signals via its medium-gain
antenna.

The test showed the high-gain antenna is working
well, and engineers will begin using that link regularly at
the end of the month.

On May 4, engineers successfully ran a thruster calibration test designed to measure the small velocity
changes that occur when the spacecraft fires its attitude
control thrusters.

As of early Wednesday, May 9, Odyssey was 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.

Mission Update:
Friday, April 27, 2001

A burst of activity from the Sun may have tripped a switch earlier this week aboard the Mars Odyssey spacecraft, but mission controllers said Friday afternoon that an onboard computer had been resent Wednesday morning and the spacecraft was doing fine.

"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 onboard memory."

Engineers are in the process of redesigning the Mars Odyssey 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.

On April 19 flight controllers turned the spacecraft and pointed its thermal emission imaging system (THEMIS) instrument at the Earth and Moon to calibrate it. All calibration objectives were met, mission controllers said.

Next week, the team will turn on the Martian radiation environment experiment (MARIE) and prepare to transition to the new cruise attitude.

Mission Update: Thursday, April 12, 2001

The first trajectory correction maneuver had been scheduled for Monday, April 16, but after analyzing the current spacecraft trajectory, spacecraft engineers said the move won't be necessary and they have decided to wait until later in the cruise phase to perform the first maneuver. The navigation team is currently evaluating dates in late May for a potential mid-course correction.

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.