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Old 10-March-2006, 02:58 PM
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Default MRO orbit insertion
I'm going to start a separate thread to follow today's events. Here's some info (courtesy of 01101001):

NASA TV Live Events, News and Special Event Programs:

Quote:
March 10, Friday
12 p.m. – Mars Reconnaissance Orbiter Pre-Arrival News Briefing - JPL (Interactive Media Briefing) (Public and Media Channels)

3:30 p.m. - 5:45 p.m. - Mars Reconnaissance Orbiter Coverage - JPL (Mission Coverage) (Public and Media Channel)

7:30 p.m. - Mars Reconnaissance Orbiter Post-Arrival News Briefing - JPL (Interactive Media Briefing) (Public and Media Channel)
Watch NASA TV

From the MRO Arrival Press Kit (PDF about 1 megabyte):

Quote:
Insertion Events and Approximate [Earth-Received] Times
March 10, 2006

Pacific / Eastern / Event

7:24 a.m. 10:24 a.m. Final trajectory correction maneuver (if needed)
1:07 p.m. 4:07 p.m. Start of turn to orbit-insertion attitude
1:19 p.m. 4:19 p.m. End of turn to orbit-insertion attitude
1:24 p.m. 4:24 p.m. Start of orbit-insertion burn by main thrusters
1:45 p.m. 4:45 p.m. Entry into shadow of Mars, shift from solar to battery power
1:47 p.m. 4:47 p.m. Loss of signal as spacecraft goes behind Mars
1:51 p.m. 4:51 p.m. End of orbit-insertion burn (though still out of contact)
2:01 p.m. 5:01 p.m. End of turn toward Earth pointing (still out of contact)
2:16 p.m. 5:16 p.m. Reacquisition of signal as orbiter emerges from behind Mars

All times in Earth-received time, the time at which the radio signals from the spacecraft reach Earth. The distance between the two planets on March 10 will be 215 million kilometers (134 million miles). Traveling at the speed of light, radio signals take 12 minutes to travel from Mars to Earth.
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Old 10-March-2006, 03:20 PM
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Am I missing something here? (my bold)
Quote:
1:47 p.m. 4:47 p.m. Loss of signal as spacecraft goes behind Mars
1:51 p.m. 4:51 p.m. End of orbit-insertion burn (though still out of contact)
2:01 p.m. 5:01 p.m. End of turn toward Earth pointing (still out of contact)
2:16 p.m. 5:16 p.m. Reacquisition of signal as orbiter emerges from behind Mars
How can it be out of contact till 4:47, but we re-acquire the signal at 2:16? Are those three hour windows of time at which that event will occurr, but it won't be the full three hours? Are they that uncertain as to when LOS will happen?
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Old 10-March-2006, 03:21 PM
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From the Unmanned Spaceflight Forum:

Quote:
Watch Mars Reconnaissance Orbiter's Doppler Plot in real time during MOI !
http://marsprogram.jpl.nasa.gov/mro/...l_doppler.html
Mars Orbit Insertion - Sequence of Events
http://marsprogram.jpl.nasa.gov/mro/...l_moi-soe.html
I'm trying to find out what happened with the 10:24 TCM, so far without success.
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Old 10-March-2006, 03:22 PM
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Quote:
Originally Posted by Swift
Am I missing something here? (my bold)

How can it be out of contact till 4:47, but we re-acquire the signal at 2:16? Are those three hour windows of time at which that event will occurr, but it won't be the full three hours? Are they that uncertain as to when LOS will happen?
The first column is Pacific time and the second is Eastern. (It's really hard to do tables in a post on this forum!)
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Old 10-March-2006, 04:07 PM
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Pre-Arrival News Briefing:

- Exactly on expected trajectory. Had two contingency maneuvers considered, yesterday and this morning, didn't need either. No maneuvers since last November.

- Currently being tracked by Madrid and Goldstone DSN stations. Supposed to be rainy at Goldstone but not enough to make a difference.

- MRO currently moving at 7000 mph, speeding up to 11000 mph by start of burn

- 27-minute burn, in view for first 21 minutes. Won't be able to see spacecraft for about half-an-hour.

- DSN should find signal right away. Will take five minutes to collect enough telemetry to determine success of burn. (160 bits per second data rate.)

- Expect 35-hour orbit, 250x27,000 miles. Doppler signature will indicate.

- Expect to start aerobraking in about three weeks.
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Old 10-March-2006, 04:13 PM
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- MRO safe, stable, fully charged, no engineering issues with spacecraft whatsoever

- Insertion sequence loaded, MRO enabled to burn autonomously without further orders from Earth

- Desaturation maneuver performed on Wednesday

- No command activity yesterday or today, none needed

- Small firing of attitude control thrusters two hours before burn to eliminate any accumulated momentum

- Detailed timeline: -35 pressurize tanks, -27 go to low-rate communications, ...

- Back to high-rate communications one hour after regaining comm. (High rate is 3500 times faster than low-rate.)

- Expect batteries to drop about 10% during Mars occultation.

- Able to save 60 pounds of fuel during cruise, translates to another seven months of operations. Will use most of the fuel today.

- All engines together only have about 250 pounds of thrust.

- 22:30 is nominal burn time, can go under by 12% or over by 28% and still have a tolerable orbit. (Thought he said 22:30, but must be closer to 27:30.)
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Old 10-March-2006, 04:15 PM
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- MRO operational orbit only 190 miles from surface.

- Unprecedented detail, probe beneath the surface with radar.
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Old 10-March-2006, 04:18 PM
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[What if don't hear at 2:16? What do you do?]

If we don't hear, means vehicle went into safemode. If don't hear give it 14 minutes (until 2:30) to solve problem itself. [We seem to avoiding discussion of any catastrophic, "controlled flight into terrain" sorts of failures here.]

[MRO has typical safemode responses or not?]

Vehicle does not suppress majority of its fault detection because there's plenty of redundancy. [Most spacecraft disable a lot of fault handling in critical situations because stopping an orbit insertion burn halfway through is a really poor idea.]

END OF PRESS CONFERENCE (Only ran about 17 minutes.)
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Old 10-March-2006, 05:24 PM
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3 hours to start of orbit-insertion burn.

Begins at 1324 PST, 1624 EST, 2124 GMT.
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Old 10-March-2006, 05:30 PM
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Very good. Thank you for the updates.
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Old 10-March-2006, 07:33 PM
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NASA TV coverage of the MRO Orbit Insertion events has begun -- 1230 PST, 1530 EST, 2030 GMT.

Watch NASA TV
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Old 10-March-2006, 07:35 PM
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Not that they've told us anything yet....
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Old 10-March-2006, 07:50 PM
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another great mission !


Six science instruments are included on the MRO mission. The MRO's communications capabilities will provide a critical transmission relay for the surface missions. The craft is equipped with a visible stereo imaging camera (HiRISE) with resolution much better than one meter and a visible/near-infrared spectrometer (CRISM) to study the surface composition. MRO may provide evidence which could help to uncover the reasons behind the failure of past Mars missions such as NASA's Mars Polar Lander, and the British Beagle lander launched from ESA's Mars Express. After MTO got cancelled it was decided that the MRO orbiter will be used as a telecommunications link for future missions. MRO gets its electrical power from two solar panels. Each panel can move independently around two axes of movement. The goals of the Mars Reconnaissance Orbiter are to search for evidence of water, and characterise the atmosphere and geology of Mars.
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Old 10-March-2006, 07:52 PM
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Fuel pressurization has started. This is the first milestone toward the burn.
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Old 10-March-2006, 07:56 PM
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Pressurization is going well. Next milestone is switching to the low-gain antenna at 3 after the hour.
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Old 10-March-2006, 08:05 PM
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The high-gain signal has been lost, as expected.
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Old 10-March-2006, 08:06 PM
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DSN reports a lock on the low-gain signal.
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Old 10-March-2006, 08:10 PM
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Waiting for confirmation that the spacecraft has started slewing to the burn attitude. The 160 bit-per-second data rate is extremely low, so it takes a while to get enough data in for the confirmation.
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Old 10-March-2006, 08:10 PM
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Old 10-March-2006, 08:11 PM
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Slew confirmed from Doppler analysis of the signal.
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Old 10-March-2006, 08:12 PM
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Slew confirmed from spacecraft telemetry. Next milestone is completion of the slew at 19:31 after the hour.
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Old 10-March-2006, 08:21 PM
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Spacecraft is at the burn attitude.
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