Posted on 03/08/2006 9:35:55 PM PST by NormsRevenge
WASHINGTON (AFP) - NASA scientists were nervous as an orbiter neared Mars after a seven-month voyage carrying the most expensive equipment ever sent to another planet.
"We have a tremendous amount of anxiety and concern at this particular point in time," said Jim Graf, project manager for the Mars Reconnaissance Observer (MRO).
"At the same time we feel confident, we have a very good spacecraft ... (and an) excellent well trained team," he said in a press conference from the Jet Propulsion Laboratory in Pasadena, California.
"We are about 325,000 miles (523,036 kilometers) from Mars. We're traveling at about 6,400 miles (10,300 kilometers) an hour and we are going to double our speed as we get closer to Mars," he said.
The tricky part, he said, will be maneuvering the craft into a Mars orbit. Because of the great distance, it takes 12 minutes for data to reach Earth from the craft -- and another 12 minutes for instructions to be sent back.
"There is no time for the team as a whole to react," he said.
"So we have on board all the programs we need to carry out, and the spacecraft has to do it all on its own."
"Mars is unpredictable," Graf said. The tally of travel to Mars is grim: of the 35 missions to Mars since 1960, 21 have failed.
To achieve Mars orbit, the probe's engines will begin firing at 2125 GMT on Friday for 27 minutes. That should slow the craft enough to allow its capture by Mars' gravity.
About 20 minutes later, the orbiter will disappear behind Mars for 30 minutes before it renews contact with very anxious scientists on Earth.
At first, the probe will be in a highly elliptical orbit 400 kilometers (250 miles) above Mars at the closest point and 44,000 kilometers (27,340 miles) at its apogee.
In late March, NASA engineers will start operations to bring the probe to a round orbit close to Mars so it can begin its 25-month observation mission.
The MRO carries six observation and analysis instruments to search from its outer atmosphere to below the martian surface for signs of water and ice.
At this point, I think I read 12.
93 million miles is about 8 light minutes.
Copy 12 minutes.
One way?
Speed of Light is 300,000,000 KM per second..
I would suggest 6 minutes is Way Too Long...
More like 1/2 light second..
Thanks and Thanks!
I been out all day and headed out shortly as well for a while.
No way.
6 minutes to 12 minutes is in expected range.
12 minutes one way - just confirmed it too. Mars is 1.5 the distance to the sun.
spaceflightnow.com
2200 GMT (5:00 p.m. EST)
Once communications are reacquired with MRO, the spacecraft will send a basic report, including the burn duration and the amount of slowing the probe thinks it achieved. The Deep Space Network on Earth will listen for MRO at 5:16 p.m. EST.
"There will be jubliation on the team," Rob Lock, MRO lead mission planner, predicts for the moment the signal is heard again. "It will mean out spacecraft has survived. Unfortunately, we won't know anything more than that. After about five minutes, enough telemetry will collect with our flight team to understand how well the maneuver performed -- did it burn right, the right amount of time, things like that. It will take a few minutes. Within about a half-an-hour, we'll have tracking information for our navigators to say what kind of orbit we are in."
Oops, that should be 300,000 km/sec.
they just said, they are sending a ping to the spacecraft, so in 12 minutes it will send a "here I am " back so 12 each way i would guess
Gotta double check my zeroes..
You've got an extra K in there.
ALICIA CHANG, AP Science Writer
PASADENA, Calif. - A NASA spacecraft began firing its main engines in a critical maneuver Friday to send it into orbit around Mars on a mission to study the Red Planet in the most detail ever from above.
The Mars Reconaissance Orbiter, loaded with the most sophisticated science instruments ever flown to another planet, traveled 310 million miles in the past seven months for the rendezvous.
Mission control at the Jet Propulsion Laboratory waited anxiously as the two-ton orbiter performed the riskiest maneuver of the $720 million mission.
The spacecraft was to fire its engines for 27 minutes, slowing it by 20 percent to 11,000 mph so that it could be pulled into orbit by Mars' gravity. It was to disappear behind the planet briefly, temporarily losing radio contact with controllers.
Engineers said they would not know whether the maneuver was successful until the spacecraft returned to Earth view almost an hour after the burn began.
"It's a little nerve-racking even though it's exciting," Doug McCuistion, who heads the Mars program at NASA headquarters, said earlier.
Space probes have zipped past Mars, circled around the planet and landed on the surface since the 1960s. Scientists say this latest mission is unique because the orbiter carries the most powerful cameras and other instruments to probe the planet in exceptional detail.
If successful, the Reconnaissance Orbiter will be the fourth eye on the Martian sky, joining the ranks of NASA's Mars Global Surveyor and Mars Odyssey and the European Space Agency's Mars Express.
Besides the orbiting satellites, two rovers — Spirit and Opportunity — have been rolling across opposite ends of the planet since 2004 searching for evidence of ancient water.
Flight systems manager Howard Eisen of the Jet Propulsion Laboratory said the orbiter was "safe and stable" leading up to the tricky orbit insertion phase.
Once in orbit, the spacecraft is expected to photograph Mars' surface for evidence of water-altered rocks and scout for future landing sites to send robotic and perhaps human explorers. The orbiter is also expected to relay communication between Earth and Mars.
A successful firing would place the craft in an elliptical, 35-hour orbit taking it as close as 250 miles above the surface. The spacecraft will then spend seven months dipping into the upper atmosphere to tighten the orbit.
The orbiter is expected to start collecting scientific data in November. Its primary mission will end in 2010.
NASA has had mixed success placing spacecraft into orbit around Mars, a harsh planet with a reputation of swallowing scientific probes. Two of the last four orbiters that flew to Mars in the past 15 years lost their signal before or during orbit insertion — a "sobering" track record, according to Fuk Li, who heads the Mars program at JPL.
In 1993, NASA lost contact with the Mars Observer before it entered orbit. The space agency was dealt another setback in 1999 when the Mars Climate Orbiter failed on arrival.
Launched from Florida last August, the Reconnaissance Orbiter was designed to beam back more data than all previous Mars missions combined.
___
On the Net:
Mars Reconnaissance Orbiter: http://mars.jpl.nasa.gov/mro
No - 186,000 miles per second, 300,000 kM per second, 300 million METERS per second, etc.
About 12 minutes one way is correct. But note, if the radio is transmitting, we'll see the satellite and pick up it's transmission at the same time.
Thank God for Google..
Too bad I didn't double check my figures before shooting my jets..
spaceflightnow.com
2203 GMT (5:03 p.m. EST)
Mission control has just dispatched a "ping" signal that when it arrives at Mars in 12 minutes the spacecraft should hear it.
Lol, hey I do things like that all the time!
Ping was sent to MRO at 21:58.
Message returned was "no route to host"
spaceflightnow.com
2203 GMT (5:03 p.m. EST)
MRO should have completed the first part of its turn back to Earth. This initial maneuver is designed to protect the spacecraft's instruments from facing the sun.
Yeah...course 16 Unifried engineering...as we called it. The home of the smug, all that can be modeled with an equation is called Reality. Fortunately, I had the experience of working in the Course 6 department(physics), where they looked at us as utilitarian engineers, who worked in the world of rules deemed "impossible" by us conventionalist engineers.
Of course, even THEY themselves were guilty of dismissing the ramifications of metaphysics, which was beyond their theoretical ability to contemplate, much less model.
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