Difference between revisions of "Lunar Reconnaissance Orbiter (BrianJ add-on)"
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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 |
Revision as of 02:11, 26 August 2008
Overview
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.
LRO is an unmanned mission to create the comprehensive atlas of the moon's features and resources necessary to design and build a lunar outpost. LRO focuses on the selection of safe landing sites, identification of lunar resources and the study of how lunar radiation will affect humans.
After launch, the LCROSS shepherding spacecraft and the Atlas V’s Centaur upper stage rocket will execute a fly-by of the moon and enter into an elongated Earth orbit to position LCROSS for impact on a lunar pole. On final approach, the shepherding spacecraft and Centaur will separate. The Centaur will act as a heavy impactor to create a debris plume that will rise above the lunar surface. Following four minutes behind, the shepherding spacecraft will fly through the debris plume, collecting and relaying data back to Earth before impacting the lunar surface and creating a second debris plume.
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 south pole of the moon, when the LRO spacecraft is overhead. This mission is not recommended for people recently starting to use Orbiter.
Mission Objectives
LRO
The objective of the LRO mission is to map the lunar surface in preparation for the return of human missions to the moon, which are planned to occur by 2020.
LCROSS
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
- Atlas V heavy V2 by Kev33
- IMFD 5.1m
optional add-ons
Procedures
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.
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. The scenario starts at UTC 2/28/2009 2:07:00. Launch time is UTC 2:08:07. The default camera view is Ground Observer. You have just under a minute to set up the camera to your personal preference.
At UTC 2:07:57 press the p key to start the launch countdown.
At T-5 seconds, engine ignition will happen, and the hold down clamps release at T-0. 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.
10 seconds after booster separation, press the p key again.
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 second stage ignition, the fairing will be jettisoned, and the LRO/LCROSS spacecraft will be exposed.
TLI
After SECO, while established in the 185km parking orbit, set the Left MFD to IMFD.
Also, click the HUD button in the right orbit MFD so that your HUD is set to orbit reference Earth
IMFD Configuration set-up
Click MNU, then Configuration. Click Nxt, then + to change the Mission timer to MJD mode. Click Nxt ten times to hightlight Parking Orbit Alt. Click Set, and set this to 185k
Establishing the TLI burn
Click MNU, then Course. Target Intercept should be highlighted. If not, click Nxt until it is. Click Set Click Tgt and enter Moon 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
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.
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 or UNIVPTG 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 between 1M and 2M on the opposite side of the moon. Once this is done, Select Transx in both MFD's. Select moon as the target in the right MFD, as in the LRO targeting.
Click the FWD button for stage 2, and selecg the target as Escape. Click the FWD button again for stage 3, and select the target as Moon Click the VW button for Sling Direct view. On the Left MFD, click the FWD button for stage 2. Click the VW button for slingshot view.
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 40 days
On the Right MFD, click the VAR button twice to bring up the Inc. angle parameter Click on ++ several times until the dotted yellow line is about the same size as the solid green line.
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 -- button until it is on the same side.
On the Right MFD, click on VAR four times until the outward angle parameter is shown.
Mid course correction/LRO
Course correction/LCROSS
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