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== Overview == | == Overview == | ||
− | The Lunar Reconnaissance Orbiter (LRO) is the first mission in NASA's planned return to the moon. LRO | + | The Lunar Reconnaissance Orbiter (LRO) is the first mission in NASA's planned return to the moon. LRO will launch Feb. 27, 2009, with the objectives to finding safe landing sites, locate potential resources, characterize the radiation environment and test new technology. |
The return to the moon will enable the pursuit of scientific activities that address our fundamental questions about the history of Earth, the solar system and the universe -- and about our place in them. It will allow us to test technologies, systems, flight operation and exploration techniques to reduce the risk and increase the productivity of future missions to Mars and beyond. It will also expand Earth's economic sphere to conduct lunar activities with benefits to life on our home planet. | The return to the moon will enable the pursuit of scientific activities that address our fundamental questions about the history of Earth, the solar system and the universe -- and about our place in them. It will allow us to test technologies, systems, flight operation and exploration techniques to reduce the risk and increase the productivity of future missions to Mars and beyond. It will also expand Earth's economic sphere to conduct lunar activities with benefits to life on our home planet. | ||
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The debris plumes are expected to be visible from Earth- and space-based telescopes 10-to-12 inches and larger. | The debris plumes are expected to be visible from Earth- and space-based telescopes 10-to-12 inches and larger. | ||
− | This is a difficult and challenging mission. Experienced orbinauts will enjoy the challenge of targeting the LCROSS to impact the | + | This is a difficult and challenging mission. Experienced orbinauts will enjoy the challenge of targeting the LCROSS to impact the south pole of the moon, when the LRO spacecraft is overhead. This mission is not recommended for people recently starting to use Orbiter. Familiarity with setting up |
+ | gravity assist maneuvers in TransX is a '''required''' skill. | ||
=== Mission Objectives === | === Mission Objectives === | ||
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Earth’s closest neighbor is holding a secret. In 1999, hints of that secret were revealed in the form of concentrated hydrogen signatures detected in permanently shadowed craters at the lunar poles by NASA’s Lunar Prospector. These readings may be an indication of lunar water and could have far-reaching implications as humans expand exploration past low-Earth orbit. The Lunar CRater Observing and Sensing Satellite (LCROSS) mission is seeking a definitive answer. | Earth’s closest neighbor is holding a secret. In 1999, hints of that secret were revealed in the form of concentrated hydrogen signatures detected in permanently shadowed craters at the lunar poles by NASA’s Lunar Prospector. These readings may be an indication of lunar water and could have far-reaching implications as humans expand exploration past low-Earth orbit. The Lunar CRater Observing and Sensing Satellite (LCROSS) mission is seeking a definitive answer. | ||
− | === | + | === required add-ons === |
− | * [http:// | + | * [http://orbithangar.com/searchid.php?ID=2601 Atlas V heavy] V2 by Kev33 |
− | * [http:// | + | * [http://koti.mbnet.fi/jarmonik/Orbiter.html IMFD 5.1m] |
− | === | + | === optional add-ons === |
* [http://orbithangar.com/searchid.php?ID=3165 Attitude MFD] | * [http://orbithangar.com/searchid.php?ID=3165 Attitude MFD] | ||
− | * [http://orbithangar.com/searchid.php?ID= | + | * [http://www.orbithangar.com/searchid.php?ID=2989 Telescope MFD] |
− | + | * [http://orbithangar.com/searchid.php?ID=3434 Level 9 Lunar Texture] | |
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== Procedures == | == Procedures == | ||
Accuracy of burns in this mission is '''CRITICAL'''. | Accuracy of burns in this mission is '''CRITICAL'''. | ||
+ | During this mission, especially after the TLI burn, we will be using the tools TransX or IMFD to get the '''DIRECTION''' of our burns, and using IMFD map to monitor in real time the '''MAGNITUDE''' of the DeltaV we are imparting. For this mission, usually the AUTOBURN button is '''NOT''' your friend. | ||
+ | You may wish to edit your config/Moon.cfg file and change the LAN line to | ||
+ | LAN = 2.2483 ; ascending node of equator - CHECK! | ||
+ | This will ensure a more accurate simulation. | ||
=== Launch === | === Launch === | ||
− | Fire up the '''01 - AV020 LRO launch | + | Fire up the '''01 - AV020 LRO launch''' scenario in the LRO scenarios folder |
This is a night launch so visibility is poor until after the TLI burn. | This is a night launch so visibility is poor until after the TLI burn. | ||
− | The scenario starts at UTC | + | The scenario starts at UTC 2/28/2009 2:07:00. |
− | Launch time is UTC | + | Launch time is UTC 2:08:07. |
− | The default camera view is Ground Observer. You have just | + | The default camera view is Ground Observer. You have just under a minute to set up the camera to your personal preference. |
− | At UTC | + | <nowiki>At UTC 2:07:57 press the</nowiki> '''p''' <nowiki>key to start the launch countdown.</nowiki> |
− | |||
At T-5 seconds, engine ignition will happen, and the hold down clamps release at T-0. | At T-5 seconds, engine ignition will happen, and the hold down clamps release at T-0. | ||
− | The Atlas V-401 | + | The Atlas V-401 booster has a launch autopilot to guide you until booster cutoff. Pressing '''p''' again will disable the autopilot, but this is '''NOT''' recommended, as the booster has no RCS control. |
− | <nowiki>10 seconds after | + | <nowiki>10 seconds after booster separation, press the</nowiki> '''p''' <nowiki>key again.</nowiki> |
− | This will ignite the | + | This will ignite the second stage Centaur engine, and engage the second state autopilot. Pressing '''p''' again will disengage the second stage autopilot, |
+ | but again, this is not recommended. While the second stage does have RCS control, the autopilot will put the vehicle in a circular 185km parking orbit. | ||
− | Shortly after | + | Shortly after second stage ignition, the fairing will be jettisoned, and the LRO/LCROSS spacecraft will be exposed. |
=== TLI === | === TLI === | ||
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Also, click the '''HUD''' button in the right ''orbit'' MFD so that your HUD is set to orbit reference Earth | Also, click the '''HUD''' button in the right ''orbit'' MFD so that your HUD is set to orbit reference Earth | ||
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==== IMFD Configuration set-up ==== | ==== IMFD Configuration set-up ==== | ||
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Click '''Set''' | Click '''Set''' | ||
Click '''Tgt''' and enter '''Moon''' | Click '''Tgt''' and enter '''Moon''' | ||
− | Click '''Nxt''' | + | Click '''Nxt''' so that the ''Tej'' parameter is highlighbted. |
− | + | Click + or - repeately until the ''dV'' parameter reaches a minimum. This should be about ''3.13k'' | |
− | + | Click '''Pg''', then '''BV''', then '''AB''' | |
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− | Click | ||
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+ | Sit back and wait for the burn. You may wish to use time acceleration to get close to the burn time, but set it back to 1x acceleration once you get close. | ||
+ | ''Note for Brian: It may be possible to use an offset in IMFD to target a polar orbit in the TLI. I think AMSO does something like this. It might be worth checking out, but it may make the LCROSS targeting harder. '' | ||
+ | When the TLI burn is complete, click on the '''BV''' button to restore the main IMFD Course target intercept screen | ||
+ | '''Do not jettison LRO yet''' | ||
+ | === Lunar targeting/LRO === | ||
+ | When you reach 32M altitude above the Earth, a piece of orbital debris will puncture the fuel tank of the centaur and drain all of its fuel. It is '''critical''' that you get your targeting done for both LRO and LCROSS before this time, as once that happens, your deltaV budget is severely limited. | ||
+ | At about 21M altitude above the earth, select TransX in the Right MFD. | ||
+ | Click on the '''--''' button until the target is ''Moon'' | ||
+ | Click '''VW''' once so the View is ''Manoevre'' | ||
+ | Select TransX also in the Left MFD. | ||
+ | In the Left MFD click '''FWD''', then '''VW''', so that the view is 'Encounter' | ||
+ | In the Right MFD click '''++''' so Manoevre mode is ''On'' | ||
+ | Click '''VAR''' 5 times so that ''Ch. Plane vel.'' is displayed | ||
+ | Click '''ADJ''' so that ''Medium'' adjustment mode is entered. | ||
+ | Click '''--''' until the ''Min Alt.'' parameter in the Left MFD is over 50k | ||
+ | Our goal here is to end up with an ''Inclination'' parameter in the left MFD as close as possible to 90 degrees, and the ''Min Alt.'' parameter as close as possible to 50k. | ||
+ | In the Right MFD click '''VAR''' 3 times so that ''Prograde Vel'' is selected. | ||
+ | Click on '''ADJ''' 3 times for ''Super'' adjustment mode. | ||
+ | Click on '''++''' or '''--''' until ''Min Alt.'' is close to 50k and ''Inclination'' is close to 90 degrees in the Left MFD. | ||
+ | Keep repeating these adjustments, using finer adjustment modes until you get as close as possible to the required parameters. Work quickly though, as the orbital debris is getting closer and we still have to target the LCROSS spacecraft. | ||
+ | In the Right MFD click '''VW''' to get ''Target view'' | ||
+ | Use rotation mode to get the cross as close as possible to the center of the target. | ||
+ | '''Do NOT make the burn yet''' | ||
+ | Use the planetarium view '''F9''' key to make sure you are pointed in a generally northerly direction (towards Polaris + or - 30 degrees or so) | ||
+ | If you are pointed in a southerly direction, the transx targeting will have to be re-done using '''++''' Ch. plane vel. instead of '''--''' | ||
+ | Set the Left MFD to IMFD. | ||
+ | Press the '''MNU''' button and select Map mode. | ||
+ | Press the '''TGT''' button and enter '''Moon''' | ||
+ | Press the '''Sel''' button until ''Ref Moon'' is displayed. | ||
+ | Watch the PeA parameter as you make a low dV burn with the Centaur engine '''Ctrl-numpad +''' When the Pea gets to +50k, STOP the burn with the | ||
+ | '''numpad *''' key. As it gets close you may with to use translation mode and the '''numpad-6''' key. There is no reverse translation. Don't overshoot by very much, if at all. Some dV will be added by LRO jettison which we will have to correct later. | ||
+ | Press the '''j''' key to jettison LRO. | ||
+ | On the Right MFD click '''VW''' twice to get back to ''Maneuver view'' | ||
+ | Click '''VAR''' until Maneuver Mode is displayed. | ||
+ | Click '''++''' to turn Maneuver mode ''Off'' | ||
+ | === Lunar targeting/LCROSS === | ||
+ | * Swingby of moon is passive (no thrusting) | ||
+ | * 81 days in post-swingby cruise orbit | ||
+ | * Current baseline is 3-month trajectory with south pole impact | ||
+ | * Two revolutions in high ecliptic inclination (~50 deg), 40-day period Earth orbit | ||
+ | |||
+ | |||
+ | After the LRO is jettisoned, swing the Centaur around 180 degrees. Use the finely graduated scale on the hud, or Attitude MFD | ||
+ | to do this. When the Centaur is pointed 180 degrees from where it was when you made the LRO targeting burn, make another small burn, again watching | ||
+ | IMFD map so that the final PeA is about 2M on the opposite side of the moon. Select IMFD on the right MFD | ||
+ | Click '''MNU''', then '''Course'''. Click '''NXT''' 4 times so that ''Delta Velocity'' is highlighted. Click '''Set'''. | ||
+ | Click on '''TGT''' and enter '''Moon''' as the target. Click '''Nxt''' 5 times so that ''dVf'' is highlighted. | ||
+ | Click '''Set''' and enter '''0'''. | ||
+ | In the Left MFD click '''PG''' then '''Plan'''. The green line of our orbit should turn blue. | ||
+ | In the Right MFD click '''+''' repeatedly. The ''RIn'' parameter in the Left MFD should increase. If not, Click '''-''' until it does. | ||
+ | Also watch the ''PeA'' parameter. Do not let it go negative. | ||
+ | When ''PeA'' gets too low, click '''Nxt''' on the Right MFD so that ''dVp'' is highlighted. | ||
+ | Click '''-''' until ''PeA'' in the Left MFD is back to around 2M. Setting '''Adj''' to 10x may be necessary, but return it to 1x when finished. | ||
− | + | Keep repeating these adjustments until ''Rin'' is close to 90 degrees and ''PeA'' is close to 2M. This is just a ball bark "rough in" to make our transx tageting easier. The numbers do not have to be exact. '''Work quickly''' though. Liberal use of the '''Pause''' function is encouraged. | |
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− | + | In the Right MFD, click '''Pg''', then '''BV'''. | |
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− | + | Use rotation mode to align the cross in the center of the target and then select translation mode and use ''CTRL-numpad +''' to burn until ''BT'' is close to ''0''. AutoBurn is not recommended. | |
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− | + | Once this is done, in the Left MFD click '''PG''', then '''Plan''', so the orbit line turns green again. | |
− | + | Select Transx in both MFD's.Select moon as the target in the right MFD, as in the LRO targeting. | |
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Click the '''FWD''' button for stage 2, make sure the view is ''Setup'' and select the target as ''Escape''. | Click the '''FWD''' button for stage 2, make sure the view is ''Setup'' and select the target as ''Escape''. | ||
Line 275: | Line 176: | ||
There will be a green line extending from the center of the moon to hopefully past the edge. This is an edge-on view of our current approach to the moon. | There will be a green line extending from the center of the moon to hopefully past the edge. This is an edge-on view of our current approach to the moon. | ||
− | We need to fine tune this approach to give us a lunar gravity assist which will result in a highly inclined orbit around the earth with a period of | + | We need to fine tune this approach to give us a lunar gravity assist which will result in a highly inclined orbit around the earth with a period of 40 days |
On the Right MFD, click the '''VAR''' button twice to bring up the ''Inc. angle'' parameter | On the Right MFD, click the '''VAR''' button twice to bring up the ''Inc. angle'' parameter | ||
− | Click on ''' | + | Click on '''--''' several times until the dotted yellow orbit is about the same size as the solid green line. |
It does not have to be superimposed in the same place, but of a similar diameter. | It does not have to be superimposed in the same place, but of a similar diameter. | ||
On the Left MFD the dotted yellow line should be on the same side (more or less) of the moon as the green line. If it is on the opposite side, | On the Left MFD the dotted yellow line should be on the same side (more or less) of the moon as the green line. If it is on the opposite side, | ||
− | click on the ''' | + | click on the '''++''' button until it is on the same side. |
On the Right MFD, click on '''VAR''' four times until the ''outward angle'' parameter is shown. | On the Right MFD, click on '''VAR''' four times until the ''outward angle'' parameter is shown. | ||
− | Adjust this parameter, and the Inc. angle parameter until the dotted line is superimposed | + | Adjust this parameter, and the Inc. angle parameter until the dotted line is superimposed on the solid green line in the slingshot view. |
− | + | ||
+ | This is our current trajectory. Now we need to adjust the trajectory to impact the moon in 2 orbits with a 40 day period. | ||
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On the Right MFD, click '''VW''' so that the setup view is shown | On the Right MFD, click '''VW''' so that the setup view is shown | ||
Click '''VAR''' 3 times so that ''Orbits to Icept'' is shown | Click '''VAR''' 3 times so that ''Orbits to Icept'' is shown | ||
Click '''++''' 4 times so that the ''Orbits to Icept'' parameter is 2.0 | Click '''++''' 4 times so that the ''Orbits to Icept'' parameter is 2.0 | ||
− | Now we must figure out what our ''Enc. MJD'' should be. Take the current MJD and add | + | Now we must figure out what our ''Enc. MJD'' should be. Take the current MJD and add 85 to it. (5 days to reach the moon, then 2 orbits of 40 days each.) For the Feb 28 (UTC) launch this would be 54890 + 85 = 54975. This is the ''Enc. MJD'' we will be shooting for. |
Click '''VW''' again in the right MFD to get back to ''sling direct'' view. | Click '''VW''' again in the right MFD to get back to ''sling direct'' view. | ||
Adjust the Inc Angle to get as close as possible to the desired MJD. | Adjust the Inc Angle to get as close as possible to the desired MJD. | ||
− | + | Click '''VAR''' so that ''Outward angle'' is displayed. | |
− | + | Click '''ADJ''' twice so that the increment is ''Fine'' | |
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− | Click '''ADJ''' so that the increment is ''Fine'' | ||
Adjust ''Outward angle'' to get the Cl. App. as close as possible. | Adjust ''Outward angle'' to get the Cl. App. as close as possible. | ||
− | My current solution is Inc Angle of | + | My current solution is Inc Angle of -115.18 degrees and Outward angle of -47.54. Enc MJD is 54978.5013, and Cl. App is 1.747M<br> |
Your Mileage may vary. | Your Mileage may vary. | ||
− | + | Once a solution has been reached, click '''BCK''' twice on the Right MFD. The View should be ''Maneuver'' and Maneuver mode should | |
+ | be ''off''. Click '''++''' to turn Maneuver mode ''on'' | ||
+ | Adjust Prograde Vel. and Ch. Plane vel. until the dotted yellow line on the Left MFD lines up with the solid green line. | ||
+ | R. Inc should be as close as possible to 0, and Pe Ratio should be as close as possible to 1.000. | ||
+ | Once this is done, click '''VW''' in the right MFD to get to ''target view''. | ||
+ | Use rotational thrusters to get the cross in the middle of the target and burn until ''Rel.V'' is as close to 0 as possible. | ||
+ | Click '''VW''' twice to get to maneuver view, Click '''VAR''' to get to ''Maneuver mode'' and turn it off. | ||
+ | Look at the Left MFD to see how you did. Additional corrections may be done as you get closer to the moon. | ||
+ | === Mid course correction/LRO === | ||
+ | Switch focus back to LRO. | ||
+ | Press the '''k''' key to deploy the LRO solar panels | ||
+ | Once the panels have fully unfolded, and rotated to face the sun, | ||
+ | press the '''g''' key to deploy the antenna | ||
+ | In the Left MFD select IMFD, click on MNU and select Map. | ||
+ | Make sure TgT is Moon, and click Sel until Ref is Moon. | ||
+ | Wait until PeT is about 350k<br> | ||
+ | Select IMFD in the Right MFD | ||
+ | Click on '''MNU''', then '''Course'''. Click '''Nxt''' 4 times until ''Delta Velocity'' is highlighted, then click '''Set'''. | ||
+ | Click '''Nxt''' 5 times until ''dVf'' is highlighted, click '''Set''' and enter '''0'''. | ||
+ | Click on '''TgT''' and enter '''Moon'''. | ||
+ | In the Left MFD, click '''Pg''', then '''Plan''' so that the green line turns blue. | ||
+ | In the right MFD adjust '''dVp''' and '''dVf''' so that ''RIn'' and ''PeA'' in the left MFD are as close as possible to 90 degrees and 50k respectively | ||
+ | When these adjustments are finished, click '''PG''','''BV''', then '''AB''' in the right MFD. | ||
+ | When the burn completes, click '''Plan''' in the left MFD so the blue line returns to green. | ||
+ | Repeat these adjustments as necessary as you get closer to the moon. | ||
+ | === Course correction/LCROSS === | ||
+ | Switch focus to AV020 Centaur. Select TranxX in both left and right MFDs | ||
+ | === orbit insertion/LRO === | ||
+ | === LCROSS orbit correction 1 === | ||
+ | === LCROSS final moon targeting === | ||
+ | === LCROSS pole targetinjg === | ||
+ | === LCROSS LRO targeting === | ||
+ | * ~7 hours prior to impact, LCROSS will separate from Centaur upper stage and perform a ~10-minute delay maneuver (~30 m/s) to enable LCROSS to fly through Centaur impact plume | ||
+ | == External reference documents == | ||
− | + | [http://lcross.arc.nasa.gov/docs/astrWorkshop/Galal_Orbit_Design_Galal_Final.ppt LCROSS Astronomer Workshop]<br> | |
− | + | [http://lcross.arc.nasa.gov/ NASA LCROSS page]<br> | |
− | + | [http://lunar.gsfc.nasa.gov/ NASA LRO page]<br> | |
− | + | [http://lroc.sese.asu.edu/ ASU LRO Camera Page]<br> | |
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