A Corner of the Universe for Orbiter


#1

So, the last Christmas flight did it. Orbiter got its hooks in again. It is not new (despite updates, it has been going for donkey’s years), but it is a great simulator to become familiar with the concepts of space flight through numerous vessels and situations, and with the real solar system of ours, and no lasers or trade objectives (not saying it is not exciting, as in Elite) to distract you from learning something new about space physics every time you fire it up. Not to mention it is fun just…

This is a quiet rant corner for the simulator I feel should have a thread on Mudspike. Flights, AARs, stories, maths and physics, anything applicable. Maybe even some development, to get my teeth back into MSVS C++ and OAPI (I’m generally a Code::Blocks GCC guy, since I stopped playing around with Orbiter)…

(here checking what I remember of setting up VC++ IDE. Seemed to have not forgotten all that much in VS2010, happily.)

So, a Saturday morning off, and un-inclined to do any work at home of the mountain of tasks that need to be faced. I figured I should kick off putting in some training for @PaulRix ´s challenge of going to the Moon and back. There were several options, starting with fictitious concept vessels or realistic add ons. That is a no brainer; it has to be the Saturn V. That narrowed it down to two options; the higher fidelity NASSP, which has simulations of the real Apollo flight computers and autopilot, or the simpler AMSO, manually flown and which can use the standard Orbiter MFD functions.

Bearing in mind the time investment to learn the systems of NASSP (and considering there is a new “high fidelity” sim that includes Apollo), I opted for AMSO, for some hand flown orbital insertion.

The object is to learn inter planetary stuff, and how one might properly plan for such a flight with minimal instrumentation. I am reasonably familiar already with Earth orbit operations on Orbiter. Visiting other bodies is not something I did much of even when I did fly Orbiter a lot. The object is to understand it. There are several differences (or rather, additional concepts) to flights that involve transfers and proximity to other gravitational bodies.

Also, the navigation changes. For Earth orbit, references to the planet’s equatorial plane make it fairly simple and familiar to get to grips with. As soon as you are considering visiting other worlds, trying to position oneself with reference to the “home” planet’s equatorial plane is just going to cast one into a realm of confusion. Here, we must slip the hyper-surly bonds. There’s a better reference, applicable to determining positions for all the bodies of the solar system; the ecliptic. Now, because the Moon orbits the Earth, and has a reasonably constant inclination through the nodes to its equatorial plane, you could get away with using the former reference, but it is wiser to prepare for further exploration by getting used to the ecliptic in the paddling pool.

I am not going into it in any depth, just yet. This is a familiarization run, with tools I am a little rusty with. The scenario: July 16, 1969…

I wanted to wait for the coincidence of the nodes of the Moon’s orbit with the orbit I would obtain launching from Cape Canaveral. The location of the complex is not accidental. Its latitude coincides with the inclination of the natural satellite, and therefore requires minimal fuel wastage maneuvering to the correct inclination post launch. The MFDs are set up. Surface reference left, and plane alignment right…

What I am waiting for here is a relative inclination (RInc) as close to zero as possible, and a rate of change of zero. Visually, on the graphic representation, this will be easy to identify, a the position radius line (green) will be perpendicular to the diametric line (yellow) that links the ascending and descending nodes.

A further visual representation can be referenced, less precisely, from the map MFD screen. I am not keen on this view, generally, but it does show what I am waiting for…

My “potential” orbital plane, before launch, stays put, while the Moon’s slowly creeps westward as the planet rotates.

As the relative inclination comes down, the boarding gangway and cranes are retracted. Launch time is near…

And there it is, on the align plane screen…

Inclinations to the ecliptic as equal as they will get (RInc as close to zero as possible), Longitudes of Ascending Nodes matched, and rate of change zero. Almost perfect. Lift off…

The heading solution for this one is easy. You can plainly see it without calculating it (as I had to for the Shuttle flight). 090º. Okay, I am not being completely faithful to the original mission there, but I am making it a darn bit easier to match the orbits. A little over a minute after lift off, heading established, 7.6 km up, half the first stage’s fuel consumed, linear acceleration increasing as mass is reduced, and pitched back to around 70º from the horizon to keep the orbital speed component increasing slightly. The main objective is to get above the densest part of the atmosphere so that I can pitch abck further (flatter trajectory) and use the second half of the first stage burn to inject some serious initial orbital speed, before it burns out. At the illustrated point, about to surpass Mach 1, it is certainly time to start doing that…

Approaching two minutes, the critical part here being to keep the angle between the vector and the pitch of the vessel as close to one another as possible. This avoids wasting precious thrust keeping the trajectory on an upward, accelerating trend by keeping the “nose too high” in relation to the direction of travel. It actually takes practice, manually, as that vector will fall away of its own accord, and going too flat too early will result in not getting to the target altitude. It is harder than the Shuttle. This is my third attempt. The first one resulted in a full 30+ km below the target 190 km orbital altitude, and the second one, which was going a bit better, had a failure during the last half of the stage two burn that forced an abort mission…

A gratuitous view of the Saturn V going for it. Almost looks like it is going straight for the Moon in a direct ascent…

Nearing first stage cut off, pitched back to 30º, going through 2,000 m/s orbital speed, and linear acceleration at a peak. The HUD mode is now in orbital reference, and note that the Moon is slightly left (south, as we are upside down going east) of the central orbital line. After separation, it will be among the priorities to correct that deviation…

As the Moon flights were staged events, here goes the first of them separating (sorry guys, I cannot miss an opportunity for a solid elbow in the ribs of “theorists” * :slight_smile: )…

Followed by the skirt separation and the abort tower jettison…

In this simulation, the expended tower passes perilously close to the accelerating rocket…

We are into second stage burn. Time to sort out that inclination issue with the Moon´s orbit. Orbit align MFD screen up. Cant the vessel over slightly to the south of the orbital trajectory to add thrust component from the north. Five degrees should do…

It took about a minute to resolve. Centered back on the orbital track, the Moon is now inline…

I am beginning to struggle again in that shot, by the way, as the vector has fallen off excessively, and the orbit risks ending up low again. But there is still quite a reserve of fuel left in that second stage yet, and I avoid letting the apogee get behind me. Orbital speed keeps on coming up. Two minutes later, everything is back under control. Second stage is nearly done…

And there it goes, the bulk of the orbital insertion achieved by it, as it should. On the third stage now, for the final insertion…

The third stage is a re-ignitable one. In Orbiter, it can be reignited as many times as you like. In reality, it should only be ignited twice, while acting as part of the vessel. Once at second stage separation up to orbit, then once more for the trans lunar injection. After that, it had to be jettisoned. It fired once more after separation to place it into either a graveyard solar orbit or a lunar impact, to discard it. For realism, I am only igniting it twice.

At 11:22 elapsed time since launch, I have finally nailed the correct apogee altitude at 190 km. I do not want to waste too much fuel at this point, as I have a TLI to execute, and am not sure how much of that remaining it will need to use…

Nearing the end of the insertion at 12:43, I throttle back prior to cut off to ease in the final circularization of the orbit. I am looking at the eccentricity value at this point, and juggling tiny pitch inputs to keep the vertical speed as close to zero as possible, and all the time keeping the vector centered on the orbital track reference line to avoid the inclination straying again…

At 13:10, third stage cut off. Both the red AP (apogee) and PE (perigee) flags are visible in the altitude tape, the eccentricity is at 0.0002, and the inclination to the ecliptic is 5.25º, just under 0.2º of perfect alignment with the Moon’s inclination. These are all good things. Check…

Now the fun part. Setting up the transfer orbit to the Moon. The transfer MFD screen is brought up on the left (on the right I brought up the align planes screen to keep track of the nodes and monitor the rate of change at zero). Now, this computer takes all the heavy calculation out of transfer planning. It is very easy to use. Set the hypothetical transfer orbit (HTO) on, and hit the increase Delta Velocity button. Soon, it will start showing the expanding elliptical orbit you are creating in a green dashed line from the source of the burn (the ejection), represented by the green dashed radial. The Dv read out tells you how much “extra” speed you will need to achieve that ellipse…

The yellow, outer solid line circle is the Moon’s orbit. Dv is increased until the end of the green dashed ellipse exceeds the radius. At this point, a solid gray radial line will show the angle at which your transfer orbit will intercept the Moon’s orbit (not necessarily the Moon, yet). No more Dv need be added (any more is just excess fuel)…

Finally, the ejection needs to be aligned, so you know where to start the TLI. The EJ+ and EJ- buttons rotate the transfer ellipse around. You want to place the solid gray radial over the dashed yellow radial line, which is the place the Moon will be at the end of the transfer. The solid yellow radial line is the Moon’s current position, and the solid green radial is your current position. You will orbit faster than the Moon (obviously, you are much closer to Earth). When your green solid line is over the green dashed line, it is time to burn prograde to start the TLI…

A quick, final verification of the orbital status confirms the good news, again. The Longitudes of the Ascending Nodes (LAN) are roughly equal, and other previously referenced parameters are still good. The slight difference of 0.18º of inclination will be corrected manually during the TLI…

Now we wait, not particularly bothered about keeping the vessel pointing in any specific direction during that wait. No reason…

Finally, at 1:13:35, we are ready for the burn to transfer…

Fired up, the ellipse growing. I do this whole procedure in manual control, as you can steer around the vector to fine tune the obliquity and the argument of the perigee…

Eventually getting the orbit to coincide with the planned trajectory. Cut off. We are finished with stage three, now. Note the solid green ellipse matching the dashed ellipse…

Coming into the dawn over Hawaii…

Time for the final operation of departure. Extracting the LEM. This will involve some virtual cockpit work, too, as there is a nifty recreation of the alignment guide. Now over Baja California. First thing, though, orient the craft so that there is some light on the subject…

And separate the CSM from the third stage. The fairings covering the LEM jettison, too…

Then gently spin around to face the docking ports to each other…

First look through the docking guide…

Combined usage of RCS in linear and rotation modes to line up appropriately on the disk, then gently thrust in with the linear RCS…

Despite my best efforts to null any rotation of the third stage before separation, it did have a bit of residual rotation around the longitudinal axis…

But nothing that could not be sorted out promptly again by rotating the CSM, too. Nearly there…

Here’s what that distance looks like from outside…

Ahhh! Contact! Immediately pull the LEM from the third stage with some retro lineal RCS…

And put a slow rate of separation between the remains of the third stage and the CSM, so that it can do its timed orbital discard maneuver without me being too close…

That is it, as far as leaving Earth is concerned. The rest will be the slowly decelerating coast up the ellipse, until the Moon´s gravity begins to capture the CSM. It all looks pretty good still, on the orbital data screen. I am very happy that I managed to keep the Longitudes of the Ascending Nodes aligned, and the inclination. As we cross that descending node, that empty square on the extended, yellow dashed line connecting the Moon’s nodes, we can effect a mid course correction to fine tune the arrival parameters. Time for a quick save, check the time, and the next time I fire up Orbiter with the save, I will fast forward to the true point of elapsed time and see where we are. I’ll take it from there…

That was a really entertaining couple of hours!

* I have to tell it. Sure, “fad theorists” are entitled to their opinion. But I grew up overseas, in a relatively small circle of known engineers who did not doubt the abilities of human kind to overcome challenges with science, skill and determination. And my South American friends had no reason to do any doubting, or just did not care. The first time I ran into a “theorist” was in England, in my late teens. I was astonished, could not believe what I was hearing was taken seriously, and thought it was a joke to start with. It dawned on me that she meant it, after a while. She believed the Earth was flat. I said we have even seen it is not flat, from space. I walked right into the prepared answer. She said “we never went into space”. I almost transiently believed I had met a different species, at that point. LOL!

Thanks for your patience. All the best.


#2

An epic AAR - thanks!


#3

Awesome! I really need to make some time to try this out! Thanks for posting!


#4

Brilliant. A great AAR!


#5

Very impressive AAR there CP! I learned all I know about Orbital Mechanics from Kerbal Space Program. It seems I still have much to learn!


#6

Really cool!
Imagine if they had all these MFD type instruments, 50 years ago…


#7

Thanks all! I did not think it would go down too well, being an old sim, and all, but was inspired to share it anyway as a result of dusting off Orbiter for the Christmas flight. :smiley:

Indeed, I do get the same feeling. As I intend to step up the challenges throughout the year on Earth to Moon flights, this is the basic first run using some of the stock MFDs. I am treating them as you might aircraft instruments during theory study, as opposed to just superficially learning their implementation for an operational goal. That is to say, comparatively, you can read an altimeter or a turn coordinator without really knowing what makes it “tick”, or you can go into the details of why the aneroid capsule can be calibrated for altitude, or the gyroscopic effects can help you determine a rate of turn. There is a lot behind the symbology of those MFDs, which I am focusing on to improve understanding of transfers and such.

I have never played it, as I do like the fact that Orbiter has our real solar system as opposed to a ficticious one. I do understand it is a fine simulation of orbital mechanics, however, from comments and from people I know on Discord who play it. I am not that surprised, as if I am not mistaken I remember KSP was developed in part on the Orbiter community forum by a member who was quite active there. I recall a thread on which it was announced as completed. I also suspect (I might be wrong) Subnautica was developed there, too, as a bit of a lightning challenge some of the members put together, and produced an under-sea exploration simulator with Unity very quickly. It was quite a thrilling and fast paced thread, in as much as the word “thrilling” can be applied to a coding point of view, LOL!

A quick update of the position. I fast forwarded the mission elapsed time by the real elapsed time since launch yesterday morning to see where I would be right now and did another quick save. Here is what we have…

All still looking pretty good. It is not the time yet to do any fine course corrections. Orbital speed falling off accordingly, as it should, and Earth´s apparent size getting smaller.

I am suddenly a bit concerned about getting back from the Moon, at the moment, as there was something I just thought of that I had not considered. I will mention more on that next time.


#8

Work the problem…

image
:wink:


#9

Mission update.

I thought I might have a picture of the eclipse to start off this morning’s post here, but… stratus.

First look at the orbital data for the Moon, 200,000 km direct distance yet to converge, but passed the midway point of the transfer ellipse, and speed still falling off.

Here, I am noting the inclination of the projected orbit around the moon. 173.83º. I am looking for as close to a lunar equatorial orbit as possible for the arrival, and this value is good news. Still no course corrections required.

Of course, it is a retrograde orbit. Looking down on north, the Moon will be intercepting from the right of the vessel’s trajectory, will pick us up at just prior to the point of apogee dwell, and which will result in it pulling us into an orbit clockwise around the Moon (opposite way around from what we did launching from Earth).

What was (is) bothering me about the return. The Transfer MFD is only good for plotting transfers from central body to orbiting body, or from two bodies orbiting a common body. It is not able to plot from an orbiting body to the source/focus body. So I am on my own, where “precise” help from the MFD is concerned, for getting home.

However, if we are orbiting the Moon, we are also technically orbiting Earth in the grander picture, yeah? So with a bit of simple calculation we should be able to use the Orbit MFD, focused on Earth, to effect the Trans Earth Injection on the lunar longitude at the antipodean of the one facing Earth (or wait, no. That would be thrusting against the inertia of the lunar orbit - which may or may not be what we want, in the big picture. See, that is what is confusing. I will think this through!). Course corrections en route will certainly be necessary, as it would be a very “general direction of” method.

We will see how that goes and cross that bridge when we get to it :slight_smile:

There is a Lunar Module flight to complete first.


#10

Interesting thread.
I tried orbiter many years ago but never got into it. It seems it has come a long way though, so I am inclined to try…

KSP made the whole stuff a lot more accessible. I can only recommend it.
If you don’t like the small sized solar system in KSP, mods can fix that.


#11

Be careful when stirring the cryogenic-tanks. :open_mouth:


#12

:shushing_face: That is one of the failures that can happen on AMSO, I believe.

I will keep that in mind, for future reference. When I have more time to delve into a new and unfamiliar game, I will opt for this one, out of interest. What I like about Orbiter is that it forces you to learn.

I came to the conclusion that the Trans Earth Injection should, indeed, be on the far side (that is; retrograde to the Moon’s own orbit around Earth). Once broken out of the influence of the Moon’s gravity, we would find ourselves on an Earth centered, elliptical orbit. The trick will be to not over burn too enthusiastically.

The problem has sent me reading. I was avoiding getting into details until I had a general understanding of the requirements of the case. Now would be the time for some light literature for more specifics. I will start here…

A Simple Targeting Procedure For Lunar Trans-Earth Injection.pdf

Mission update:

Now in the influence of the Moon. The speed reached its lowest value, and is now rising again as we close on the Moon. The pass requires some adjustment, now. While still a way out, it is a time to do a rough adjustment on the perilune, as it is quite far out. Less fuel will be wasted doing that adjustment at this point than when we are establishing orbit. A lot of fuel will likely be used burning into lunar orbit later, and everything we can save now needs to be saved. So, it is a small amount expended now with hopes of saving a larger amount later…

Before and after shots on the Orbit MFD, right side.


#13

This is really cool!

Being one of the “elders” on the Mudspike forums, I actually remember the Apollo 11 landing & first step on the moon. The TV picture was B&W and contrasty, but you could make out what was happening. Reading your AARs is like being there again…but in color! :slightly_smiling_face:


#14

I am far too young (cough) to remember Apollo 11 :slight_smile:, even though I was already among the living. But, I do have now faded memories (among my earliest) of the last one, Apollo 17, on TV. We were in the UK, after coming back from Ethiopia for a home leave. One of the Imperial Ethiopian Air Force Canberra pilots was visiting us. I do not remember too much of what I saw on TV, so I cannot say even if it was in color or BW, but I do recall what seemed to be inspiring and quite excited conversations between my Dad and the Ethiopian Major about it. I made what model I could of the “rocket” with Stickle Bricks (do they still make them?). The model was criticized, and I was asked to add the stages. LOL!

…and with a slightly less competent crew, LOL!

So yeah…

Mission Update:

As mentioned, I am playing this first run more or less by ear to get a feel for it. At some stage I am going to have to put some numbers down. That has been reinforced by a slight mismanagement of the perilune adjustment: I took off a bit too much orbital speed during the maneuver, and as a result the convergence with the Moon has degraded over the last few hours into a projected impact with the lunar surface :anguished:

Note the PeA at minus 670 km. That is, subterranean. I should at least have done a calculation on the required orbital speed for lunar orbit at the present radius, true anomaly and eccentricity. I can do that, so there was no excuse not to except for the fact that the orbit is at present hyperbolic, which was throwing me a bit. That is new, unfamiliar territory.

Anyway, I have to pick it up again. Vessel positioned for the recovery burn, plus an offset to try and whittle the inclination a bit further towards a full 180º…

Gentle burn initiated…

Perilune picked up again, and inclination as close to 180 as I can get it…

I might have to do that procedure again, before the insertion burn. I want approximately a 150 km altitude orbit. But. I am also concerned by fuel. Granted that for the return I will be a great deal less massive after expending the LEM. However, I do not want to use much more than half the fuel during the insertion. I will need the Dv for the break out of lunar orbit, plus some maneuvering along the way. I will be taking whatever orbit I get by 8,000 kg remaining.

I will have to put the mission on hold this weekend (as from Thursday evening). Going around South America again for a couple of days (work, not play). But I will be back. And, of course, I estimate tomorrow we will be seeing the orbital insertion at some point. I can at least get that far on this charge. :smiley:


#15

Well…that is one way that the CM pilot would get to visit the moon too. :wink:


#16

CM pilot visiting the Moon? Sacrilege! No way on Earth… uhm… wait. No way we can allow that to happen.

But he is certainly trying. As expected, perilune has dipped below the lunar surface again. Not long for the orbit insertion now, either…

Small correction burn executed…

Close enough to the Moon now that if there was any sunlight on the subject we would have good screenies of it. Unfortunately, the approach has been via the shaded side, so we see nothing of it. We are still getting good, albeit distant views now, of home…

Standing by for orbital maneuvers in the dark!

EDIT:

Adding it onto the previous post. Last input for tonight. Another small adjustment…

Close, now.


#17

Mission Update:

At just over 104 hours since launch, we got out first look at the terminator on the Moon’s surface, as our view angle on it changes during closure…

Crossing the ascending node an hour later and approaching the perilune, we begin our orbit insertion burn…

At 105 hours and 12 minutes, we finally get the orbit out of hyperbolic and around the Moon itself…

Reducing the thrust slowly during the circularization. As mentioned before, I have limited myself to a maximum burn down to 8,000 kg of fuel, for return purposes…

Cut off at 105 hours 22 minutes. 8,000 kg remaining. The orbit is still pretty elliptical. I am wondering if it is a bit too eccentric to attempt a LEM landing on the surface. This could actually be reason for a jettison LEM and an abort…

I have a couple of days to think about it, now…

We will see. At least we made it this far, ragged as it is… :slight_smile:


#18

I will just revisit this again…

Have you ever wondered what a Lunar Mile might be? Same as an Earth mile, perhaps? Well, not actually. A mile, particularly a nautical mile, is a uniquely Earth specific measurement, based on the distance of a minute of latitude at the average of the equatorial and polar radii of the planet (sorry, I loved opening my navigation courses with that!). I expect we all know that tid-bit of trivia here, but for those who might not, try it…

Average earth radius = 6,367 km
Circumference = 6,367 x 2 x Pi = 40,005 km

Divide that circumference by 360º, then by 60 minutes of degree and we get 1.852 km. The recognized distance of a nautical mile. And, the kilometer itself also being a uniquely Earth measurement, originally being considered equivalent to 1/10,000 of the distance from the equator to a pole, on a great circle.

So, if the same rule were applied to the Moon, the resultant “Lunar Mile” would be considerably shorter. The Moon’s radius is easy to remember…

One Boeing 737 km. :slight_smile: As in, 1,737 km. Circumference, 10,914 km. Each minute of a degree is, therefore, 1/2 km. That would be a lunar mile. LOL! Bearing that in mind, every degree of longitude, at the Lunar equator, would be equivalent to 30 km. That will be useful to know.

So, the Orbiter mission has now probably become a kamikaze flight. The eccentricity of the orbit I eventually obtained around the Moon is not, by any means, appropriate for the severely fuel limited Lunar Module descent stage. And I am not at all confident that even the CSM can get back to Earth, the way I have handled this. The preliminary numbers I did in a hotel room at one point last week while away on operations did not look good.

But I am going to try. Let us see how far we get. Some of the various numeric scribes…

Those are very conservative numbers, actually, but they still look tight even with the margin. Whichever way you look at it, for this orbit, the law of conservation of energy ensures that the theoretical energy you are burning off will consume almost all the fuel the descent stage of the LEM has. It will take 383 km, approximately, to slow down to zero speed in relation to the Lunar surface. That is; an equatorial arc 12.77 degrees.

I cannot from an elliptical orbit be too choosy about exactly where I am going to land. Manipulating the existing orbit around to favor a given spot will not leave me enough fuel for the retro burn. I also want the landing spot to be well before the CSM orbit’s perilune (around 500), to give me the best possible chance of at least matching that point on the ascent with a reasonably flat ascent, coasting to the CSM perilune before final insertion, so I can maximize the oribital speed acquisition of the very limited ascent stage, later. The chances of getting the two LEM astronauts back seems remote. It is never going to make the original orbit again. I have already done those notes. Let us see how this plays out.

So, time to prepare the LEM…

Undock from the CSM…

And orient it (goodness, it is ugly)…

As the engine is on the bottom, it is going to have to do the burn with the vessel at 90º to the prograde direction, not 180, so the engine is aligned backwards along the orbit track. Anyway, we are going. Approaching the apolune (as the image above depicts), we check all attitude parameters as desired, and effect the short burn to lower the perilune to the surface…

Now we wait. An hour later…

I have calculated the initiation of the full deorbit burn at a lunar longitude of E 162º. The burn will take 6.6 minutes. The energy that needs to be burned off is the potential 1,935 m/sec that would be achieved at the hypothetical perilune, and not the actual orbital velocity I will have at the fire up point (the deceleration provided by the retro burn will be slightly reduced by the subtraction of natural tendency to accelerate approaching the perilune, ref: vis viva, of course).

Coming up on E 162º, start the full burn, fingers crossed…

The idea is to keep the thrust vector in direct opposition to the path for as long as possible. Here are the results.

Orbit brought down to surface intersection…

The long slog to continue reducing the orbit…

As the orbital speed comes down to meet the decreasing value of the vertical speed, a critical moment presents itself. The lunar lander must be leveled, the thrust must be reduced to avoid ballooning, and the reaction control system must be enabled in linear mode…

The drift must be cancelled before touch down, for which the linear mode is useful, albeit weak. The only instrument that helps determine there is no drift is the longitude/latitude rate of change indication (bottom data display area of left MFD). It must be zeroed in both planes…

The landing…

Now, much fuel was remaining in the descent stage?

And while we are here, let’s check the difference between the landing spot and the CSM perilune. A difference of 19.2 degrees, equivalent to 576 km. A tiny bit far, but manegable, for the ascent. Of course, the Moon is also rotating, but as it is tidally locked to Earth, it is therefore very slow, and I only intend to keep the LEM on the surface for one orbit of the CSM, it will not affect it much.

For now, I will have to look into the AMSO manual. There is a way to get the astronauts out onto the surface, but I have not read it :slight_smile:


#19

If I’m ever a passenger on an aircraft over a vast ocean, and the plane gets zapped by lightning resulting in only 20 mins of standby emergency bus power being available…I hope you are up front. You will math our way home! :joy:


#20

“Ladies and gentlemen. Please have all your electronic devices ready for collection by our chief cabin crew member. Based on the probability of the dispersion of the level of the battery charge of each device, rigged in series/parallel, and wired into the Essential TR circuit, I estimate we will have approximately 1 hour 37 minutes of extra DC current on the Emergency Bus…”

Sigh… We do sorely need an updated version of “Airplane”.

PS:

Still have not figured out how to get the astronauts out of the LEM. The “manual” instructions I read do not work. shrug