Luna-9 and Luna-10

Version 1.0

Build: 1 Apr 2008

Orbiter addon by Andrew Thielmann (igel)
atil@pin-plus.ca

Credits

Big thanks to Thorton (Nikita Vtyurin) for wonderful meshes for this and many other addons!

Big thanks to astronavt (Dmitry Pritykin) for the most realistic and sophisticated R-7 rocket family addon!

Big thanks to all participants of the testing for the great attention to details, wonderful feedback, valuable comments and ideas!

Big thanks to the unknown source for the good-looking exhaust texture!

Dependencies and compatibility

This addon is specifically designed for the Molniya package, which is an addition to the R-7 project by astronavt. It may [happen to be] compatible with other R-7 addons and maybe even with other rockets. Addon relies on the translunar stage, that should put it on the trajectory reasonably close to the Moon. Currently it has only been tested with block L for R-7, which is the part or the same addon package.

Automation

This addon is capable of performing its mission in the fully automated sequence, from launch to finish, without pilot's intervention. Automation includes navigation autopilots, component jettison sequences and functional equipment animations. Along with the fully automated launch sequence of the R-7 addon, and fully automated operations of the block L orbital stage, this provides for the full automation of the whole flight path, from start to finish!

Composition

E-6M

Luna-9 was the first man-made object to safely land on the Moon;

Luna-10 was the first man-made object to orbit the Moon;

Both lunar probes belong to the family of the E-6 (and E-6M) Soviet lunar stations. The main goal of this design was to achieve the first lunar landing. The same design was later retrofitted to put the first satellite around the Moon.

KTDU

KTDU-5, or the "correction and breaking engine unit" as the Russian acronym spells out, forms the main bus of the spacecraft, to which all other important parts are attached. Its primary feature is indeed the powerful engine and the huge fuel supply.

PO Astro and PO Radio

PO stands for "equipment bay". There were two jettisonable equipment bays, one containing the astronavigation equipment, the other had the radar antenna and electronics, the airbags pressurization system, gas RCS for cruise portion of the mission and the supply of the gas pressure tanks. Both bays were heavy, so discarding them prior to landing was crucial to the success. On the other hand, having so much of the spacecraft functionality in the discardable units required very thorough planing and design. In fact, the sequence of events was tweaked all the time, and was not finalized until the actual Luna-9 mission.

Lander ALS

Lander (ALS stands for Automatic Lunar Station) used the same ingenious design that even in the modern days provides the most reliable way to deliver a delicate piece of equipment to a hostile world. Two airbags provided the required cushioning as the lander bounced across the lunar craters. Once the airbags were discarded, the egg-shaped lander fell to the ground heavy-end-down. Four flower-like petals opened and uprighted the lander. Rod antennas deployed. Mechanical photo system took impressive pans of the first close-up look at the lunar soil.

Airbags

Two-piece airbags were part of the lander, but were inflated from the gas tanks on the Radio equipment bay. The inflation took place shortly after the main engine started its final breaking burn. Once this was done, the equipment bays were jettisoned.

After the landing, the airbags were ejected to the sides from the lander and eventually deflated.

Orbiter ALS

The first lunar orbiter was almost as simple device as the first Earth orbiter. It carried a few small scientific instruments, but is mostly known for the broadcast of the "International" from the lunar orbit (its launch coincided with the Russian communist party congress).

Flight sequence

Launch to Low Earth Orbit

Launch occurs from Baikonur, USSR. The launch vehicle is the Molniya booster, from the famous R-7 family. This is a 4-stage version of the booster. Three lower stages deliver the payload and the orbital stage into LEO.

Launches occur at their exact historic timing, in broad daylight, with good visibility of all steps. You don’t have to do anything – the launch sequence starts automatically when you load the scenario. You don't see much until the engines are fired. Enjoy the ride! External views are very rewarding, as well as "rocketcam" views from the Block L orbital stage. (See Block L documentation for details).

If you want to fast-forward the launch to orbit, +10 time acceleration is a safe bet.

Coasting to TLI point

This portion of the flight is the chance for the Block L orbital stage to shine. I suggest you to read documentation and get familiar with this simple but effective flying machine replicated in the very historically accurate and sophisticated addon. An orbital stage is more than just another propulsion unit; it is a spacecraft of its own, and addon captures all its important features.

It is important to note, that, because of the high latitude of Baikonur, and contrary to the American Moon flights, this whole flight takes place in the highly inclined orbit, and not in the plane of Ecliptic or Lunar orbit. This makes navigation much harder. It is still possible to do it in manual mode, but standard MFDs will be insufficient. Use TransX!

With autopilot, though, you do not need to do anything other than enjoy the external and internal views from the Block L. The autopilot reports the time remaining for the precalculated burn point. You can safely accelerate up to +100 times. As you approach the burn point, time acceleration will switch off automatically.

Trans-Lunar Injection

About 80 seconds prior to ignition, Block L comes to life and starts orienting itself in a proper direction. Then the complicated and carefully orchestrated ignition procedure starts. Once the engine ignites, the ullage block is discarded. Don't miss the hard work of gimbal keeping the rocket on its course as it gains the speed. The burn takes about 200 seconds, but you can speed it up +10 times, even though the gimbal will look really crazy with time acceleration! As you approach the bun end, time acceleration will switch off, and the throttle goes down to minimize the error of the delta-V. Then, the engine goes idle, and the lunar probe separates from it to begin its solo journey.

Note how the probe passes over the Southern Europe, Black Sea and Crimea Peninsula (now in Ukraine), where the Russian Deep Space Network command center used to be located at the time of the early Moon flights.

Coasting to MCC point

This is the most boring part of the flight. +10000 time acceleration is quite common here. As the beautiful blue globe disappears behind, there is not much to see around. In the internal view, you can watch on the orbital MFD how the lunar-centric approach trajectory morphs as you get closer. Once again, when you reach the MCC (midcourse correction) point, time acceleration will stop.

Mid-Course Correction

It is not realistically possible to make a good accurate trajectory in one translunar burn. We need midcourse correction to improve it. The fully automated maneuver takes place 50 Mm from the Moon. Autopilot provides enough feedback for you to know what's going on.

MCC objective is slightly different between Luna-9 and Luna-10. Luna-9 targets the very center of the lunar disk, while Luna-10 aims at a specific "missing" trajectory, not too far away from the disk but also not too close. The autopilot also monitors the remaining fuel, and cuts the engine if the hard limit of 90% is reached.

Coasting to retrograde turn point

This is just another uneventful coasting phase. This time, however, the Moon is close enough to provide some rewarding visual background. Still, time acceleration - whichever level you choose - will be essential.

Retrograde Turn

In real life, spacecrafts of this type keep precise attitude relative to the stars through the whole active mission. In Orbiter, this is not realistic: 10000x time acceleration will screw even the most precise calculation and deplete the fuel supply in desperate attempts to fix the calculation errors. So, in our model, spacecraft is free to tumble through the cruise phase, and gets automatically oriented into the proper attitude (in our case, retrograde) at predefined time.

The spacecraft uses very low-thrust cold gas nozzles to power the turn. The nozzles and the compressed gas tanks are located on the discardable equipment bay.

Luna-9 starts the turn at the altitude of 400 k. Luna-10 coasts to the custom-calculated altitude that depends on the specific trajectory. Note that Luna-10 fires its engines not in the pericenter point, which would have been most fuel-efficient, but significantly earlier. The goal is to perform the burn while still being in radio contact with the controllers in Evpatoria (where the Soviet-era Deep Space Network hub was located). Fuel efficiency was not a problem: the spacecraft was originally designed for lunar landing, which requires way more fuel than orbital insertion will require! Even discarding the equipment bays was not needed for the orbital mission.

From down here, Luna-9 and Luna-10 follow very different mission profiles.

Luna-9

Descending to ignition altitude

Once the retrograde turn has started, the autopilot calculates the descent profile and reports the ignition altitude. It then follows a quiet descent to this calculated altitude. The engine is still silent, but the attitude control is locked in retrograde mode.

Ignition sequence

Ignition usually happens about 70 km from the surface. Note: it won't happen if the autopilot finds the fuel supply insufficient!

At the ignition moment, a lot of things are happening at once! First, the main engine is ignited, and its thrust is throttled to match the descent profile. Simultaneously, the steering engines are enabled, which are more powerful than the cold gas jets. Moments later the two airbags of the lander ALS are inflated. Finally, two heavy equipment bays are jettisoned.

Powered Descent

In just about 60 seconds, we have to slow down from the cosmic velocity to almost full stop! The engine runs full throttle all the time, with only occasional fluctuations to match the precalculated profile. There is no radar anymore, no feedback, no knowledge of the altitude, only preprogrammed sequence. No surprise it is far from foolproof and occasionally may end too high - or, more spectacularly, too low!

Parachuting and Touchdown

Yes, parachutes don't work on the Moon. Yet, this final low-energy portion of decent was indeed call "parachuting".

At about 200 meters above the ground (number is estimated, actual values may vary widely) the main powerful chamber of the engine is shut down. With almost all fuel burned, the spacecraft is so light now, that it does not need as much power as this chamber produces. Even worse, the super-powerful engine could overbrake and send you back up in the black moon sky! For the last lag, weak steering engine is all you need.

Once the main engine is disabled, two 5-meter long touchdown probes roll down. This cannot be done earlier - or they would burn in the engine flame. The probes are just spring-loaded thin-wall steel tubes flattened and rolled on the reel. When freed, they roll out like a measuring tape from the canister, get back to their tube shape and rigidly hold their memorized shape.

The probes brake at touchdown but send the signal to the autopilot. The steering engine shuts down completely. The lander cushioned in the airbags separates from the bus and bounces on the surface in the clouds of moon dust, until coming to a complete stop. well done, Luna-9!

Post-landing events and operations

Post-landing sequence runs on timer. First, the airbags are separated. As they are still inflated, they bounce quite up and away! The egg-shaped lander falls into the dust. Four petals open. Four antennas open.

Mission accomplished... well, almost. If you want a nice final touch, switch to internal view for a great photo-opportunity! :-).

Luna-10

Orbital insertion burn

The burn is quite short. The resulting orbit is pretty high and not very useful for anything rather than some nice views. But it was another first for the Soviet Union - so who really cares! :-).

Satellite ALS separation

Upon engine shutdown, the satellite ALS separates from the bus, and its antenna opens. If you have sound addon, you will be able to hear the unique hallmark of this particular spacecraft. ;-).

Manual control mode

This addon was designed mostly for autopilot flights. It is very realistic and does not really have any "easy" mode to fly - making it easy would completely screw its realistic flavor. However, it supports normal range of manual controls and has been successfully flown in full manual mode though the whole mission during the testing.

To use manual controls (other than attitude controls), you have to explicitly switch to the manual mode by M key. This way, you say that you know (or trying to learn) what you are doing. You can go back to autopilot mode - but not at all times. Autopilot often thinks many steps "in advance", and if you skipped some critical steps while flying in manual mode, autopilot might not be able to properly update its state at later time. But at least it will inform you so :-).

Also beware, that while in manual mode, you can inflict irreversible changes to the spacecraft configuration. For example, if you prematurely jettison or deploy equipment components, some of the functionality that relies on them will not be available at later time! Of course, you may do so intentionally, as a part of learning or to get nice visuals.

General configuration

Here is the example of the typical scenario sequence that declares all individual components of the spacecraft, specifies their individual variables and links them together via attachments. Custom non-Orbiter variables are located below the visual double-line separator.
Ab1:Luna9AB
  STATUS Orbiting Earth
  RPOS -4075420.84 4724991.50 2012242.72
  RVEL 476.992 3400.957 -7014.683
  AROT -27.30 20.31 8.40
  VROT -12.99 -11.44 4.43
  ATTACHED 0:0,Als
  PRPLEVEL 0:1.000
  NAVFREQ 0 0
  ===========
END
Ab2:Luna9AB
  STATUS Orbiting Earth
  RPOS -4075420.84 4724991.50 2012242.72
  RVEL 476.992 3400.957 -7014.683
  AROT -27.30 20.31 8.40
  VROT -12.99 -11.44 4.43
  PRPLEVEL 0:1.000
  ATTACHED 0:1,Als
  NAVFREQ 0 0
  ===========
END
Als:Luna9ALS
  STATUS Orbiting Earth
  RPOS -4075420.84 4724991.50 2012242.72
  RVEL 476.992 3400.957 -7014.683
  AROT -27.30 20.31 8.40
  VROT -12.99 -11.44 4.43
  PRPLEVEL 0:1.000
  ATTACHED 0:2,Luna9
  NAVFREQ 0 0
  ===========
  AB1 Ab1
  AB2 Ab2
END
PoAstro:Luna9PO
  STATUS Orbiting Earth
  RPOS -4072413.49 4745550.37 1969525.56
  RVEL 511.849 3358.912 -7030.666
  AROT 125.11 -6.34 -9.53
  ATTACHED 0:0,Luna9
  NAVFREQ 0 0
  ===========
  PO_TYPE ASTRO
END
PoRadio:Luna9PO
  STATUS Orbiting Earth
  RPOS -4072413.65 4745549.82 1969524.74
  RVEL 511.849 3358.912 -7030.666
  AROT 125.11 -6.34 -9.53
  ATTACHED 0:1,Luna9
  NAVFREQ 0 0
  ===========
  PO_TYPE RADIO
END
Luna9:Luna9KTDU
  STATUS Orbiting Earth
  RPOS 3372551.57 4568915.92 -2888134.25
  RVEL 325.791 -98.010 225.538
  AROT 122.19 -31.93 -130.18
  PRPLEVEL 0:1.000 1:1.000 2:1.000
  THLEVEL 0:0
  NAVFREQ 0 0
  ===========
  PO_ASTRO PoAstro
  PO_RADIO PoRadio
  ALS Als
  ATTACHED
END

Custom configuration

All components

  ATTACHED
To establish proper linkage between the component vessel objects, proper ATTACHED variable (standard orbiter variable) should be present in each component's scenario block. Luna9KTDU provides a special case: as its way of attaching to the parent translunar rocket can vary, assembling proper ATTACHED line is not always possible. In this case, the ATTACHED line should be present even without value, to indicate that the spacecraft is not on its own yet.

Additionally, names of the corresponding attached components should be properly specified in the corresponding custom variables of the parent vessels.

  FOCUS - 0 or 1
Override to enable or disable focus for the vessel. By default, only KTDU and lunar station after separation can be focused;

Default values don't have to be present in scenario file (to make it shorter and more readable). Use custom variables only to override the defaults.

Saved scenarios may have more variables than is documented here. These are for internal use only and are not intended to be manipulated by pilot. To understand them, use the source code of the addon.

Luna9KTDU vessel

PO_ASTRO - if attached, name of the Astro equipment bay vessel object;
PO_RADIO - if attached, name of the Radio equipment bay vessel object;
ALS - if attached, name of the lunar station vessel object;
MISSION LANDER (default) or SATELLITE     - Luna-9 or Luna-10 type mission;

Luna9PO vessel

PO_TYPE - ASTRO or RADIO     - required, specifies type of the equipment bay;

Luna9Als vessel

AB1     - if attached, name of the Airbag 1 vessel object;
AB2 - if attached, name of the Airbag 2 vessel object;

Control keys

Luna9KTDU vessel

C toggle between two camera views when in the cockpit view;
M toggle between manual and autopilot control mode;
J jettison (sequentially):
  • Astro equipment bay;
  • Radio equipment bay;
  • lunar station (lander or orbiter);
  • airbags (on lander, even after lander is separated);
E disable or enable main engine chamber;
K extend touchdown probes;
B inflate airbags on lander (when lander and Radio equipment bay are present);
Ctrl J enable/disable focus switch to the lunar station after its separation from KTDU; you may want to do it to keep your "point of view" in KTDU for alternative visuals.
Ctrl F     enable focus for all subcomponents of the spacecraft. By default, only KTDU and lunar station after separation can be focused, to avoid cluttering the switch vessel dialog; However, being able to switch to any component extends the possible range of cool visuals.

Luna9Als vessel

J     jettison airbags;
K open petals;
G open antennas;

Luna10Als vessel

K     open antenna;
P stop or play International (when antenna is open);


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