Lunar Reconnaissance Orbiter (BrianJ add-on)

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. Familiarity with setting up gravity assist maneuvers in TransX is a required skill.

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

• Attitude MFD or UNIVPTG MFD
• Telescope MFD

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 select 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 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.

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.
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.

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 ++ 3 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 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.
Adjust the Inc Angle to get as close as possible to the desired MJD.
Click VAR so that Outward angle is displayed. 
Click ADJ so that the increment is Medium 
Click ++ or --' to get as close as possible to the required date.
Once the date is as close as possible adjust Outward angle to get the Cl. App. as close as possible. 

My current solution is Inc Angle of 180 degrees and Outward angle of -79.0920. Enc MJD is 54978.5086, and Cl. App is 2.554M
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 donw, 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.

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

LCROSS Astronomer Workshop
NASA LCROSS page
NASA LRO page
ASU LRO Camera Page