I have a page on Apollo which is updated annually. Do others feel more optimistic than i do on the prospects for return? I for one won't believe we will leave LEO until the hardware to do it is actually being built.

http://www.donaldedavis.com/PARTS/Apollo30.html

Don:

I hope we've turned the corner. With the positive influences of the advent of China's manned spaceflight ambitions, the potential Russian/ESA Kliper vehicle, and the burgeoning underground of US 'private' spaceflight, plus the negative influence of NASA's deemed failures, we may yet see a sea-change in what has until now been a hostage to the US Federal budget.

And if we do, the lunatics will have - at last! - taken over the asylum!

I'm a great proponent of space science, and am quite prepared to cast a critical eye over manned spaceflight as compared to unmanned. However, all spacecraft are 'manned' in the sense that they are under our command, and in my view there's simply a continuum of, er, mannedness. What I hope we get away from is the astonishing inefficiencies of design and construction which the US has backed itself into over the years, and that we find ourselves with not only a vibrant manned spaceflight sector but also a healthy space science environment.

The classic case, to me, will be the sort of situation that we may see in a few years, if the James Webb Space Telescope gets built and gets stuck whilst halfway unfolded. All that it would take would be another Pete Conrad with a hammer...

...and without him, it'd be junk.

We need manned spaceflight to keep (notionally) unmanned spaceflight alive; not the Shuttle/ISS money-pits, but enterprises which will make sufficient contribution to those of us back on Earth as to allow a real industrial base to be built out there.

After that, the sky literally is the limit!

I hope we all see that day.

Bob Shaw

Your Apollo 11 time mirror concept is both very enlightening and depressing.

You are actually being quite optimistic when you say:
"I for one won't believe we will leave LEO until the hardware to do it is actually being built."

I, myself, wish I could be that hopeful. Don't forget, there are ISS modules sitting in a storage area at KSC which will probably never see the vacuum of space. (And, in another field, don't forget the Superconducting Super Collider that was half excavated, then abandoned).

I'll believe we really are going to do it after the initial "test flights". Don't forget, there were Apollo's 7, 8, 9, and 10 before 11's landing. When we get a launch date set for the equivalent of an Apollo 8 type shake-down mission... then I'll believe it.

Edit: (And don't forget the Saturn V's for the cancelled Apollos 18, 19, and 20 are now tourist attractions at KSC, Houston JSC, and Huntsville AL).

Heck, I'd be happy enough if they just launched the lunar equivalent of MER and had a couple-three of those wandering around the lunar landscape. There's got to be incredible topography on the Moon which we've never seen. And since you can't put an aircraft or a balloon into the lunar sky, the only way to view the moon close up is to land on it and rove around, with or without humans. I think that a lunar MER would probably be a lot more practical and longer-lived than most human expeditions. I'm not entirely sure what having human boots on the ground would add.
On the other hand, I'd love to see a human equivalent of the NEAR mission. It would be a fascinating amalgam of a moonwalk and an earth-orbit EVA. Maybe instead of "landing" on a heap of rock with almost no gravity, a ship would just rendezvous with it and "lower" the astronauts by cable -- that is, if they couldn't just hop across with an MMU! There would hardly be any need for a separate landing module, and the astronauts could skip back and forth between the command ship and the asteroid multiple times -- or so I imagine.

For a lunar MER equivalent, it would be awesome if they did a soft-lander with a restart capability, so it could rove to nearby places and hover/fly to locations further away. A hover/rover, would that be a hoover?

The proposed 'Penguin' Lunar hopper (using SDI funded technology) has recently been suggested as exactly that, primarily for use around the Lunar poles... ...presumably it would suck up dust, and, er, fluff.

As for a LunaMER, would Lunakhod be a good name?

Actually, I agree that a Moon rover would be a terrific idea - perhaps they could use the Moon as a test-bed for unmanned missions to Mars (this is not *entirely* sarcasm, though I must confess that there is a degree of said deformity in this post!).

I would think it a great idea. Imagery junky that I am, just imagine the vistas we would see! And it wouldn't be like an MER, where after two years all they will have covered is the equivalent of a short hike. Because there isn't the radio lag time you have at Mars, they could essenitally be driven by controlers watching what it is seeming in nearly real time. If the Soviets could make one travel 28 km in the 1970s, just imagine what we could do now!

Another idea I had related to the moon had to do with the Apollo negatives. Not even Michael Light had access the originals - they are cryogenically frozen to prevent them from aging. I believe the time has come to get them out and scan them at resolution so high and and a depth so great that you have the closest thing possible to a perfect digital reproduction of them. These could be then catalogued and released in a standard format similar to other imagery on the PDS. This would make the images more accessible to all, and I think make them much more compelling, as most Apollo era reproductions were crap. A reconversion of the video signal would also be cool.

Certainly, seeing a cleaned up version of Apollo 15 video (and prior) would be fun... ...and *better* than Michael Light just sets me dribbling...

My view, manned space is of the last option. The cost/benefit of unmanned space is many times superior to manned space.

Now, according to our financial strength (put the money from all world nations), we will learn more and faster about the solar system and beyond stuffs with unmanned spacecraft than the manned ones.

Starting from this point of view, I would like to send many Lunar Science Laboratory (LSL), a clone from MSL with many conditions, it would be faster, capable to drive a longer range and bring band wheels so that it can visit to more places in shorter time.

The manned space is only very well business justified for tourism!!! Why do risk to much and cost too much to send a man that a present robot can do everything what a man can and even some task will outperform to man.

The idea to catch a comet by a unmanned space is a good idea to travel faster to another planetary or Kipu Belt Oordt.

It is better start to learn as much as possible from bodies of our solar system by unmanned spacecraft and hope that the new technology will improve much that will let to drop the cost to send a man in a spacecraft with much greater safetly, speed and pleasure. This might happen beyond the year 2050....

However, I understand that the man has an instinct to conquer the beyond frontiers and the sky is of no limit.... look for a pride, applauses, shout loudly and cheer a beer every time the man poses a land of different world....


Rodolfo

"It is better start to learn as much as possible from bodies of our solar system by unmanned spacecraft and hope that the new technology will improve much that will let to drop the cost to send a man in a spacecraft with much greater safetly, speed and pleasure. This might happen beyond the year 2050....

However, I understand that the man has an instinct to conquer the beyond frontiers and the sky is of no limit.... look for a pride, applauses, shout loudly and cheer a beer every time the man poses a land of different world....
Rodolfo"

In the case of the moon, I strongly disagree. Well, in theory, I agree, but the reality is that when doing cost/benefit analysis in space exploration, you can't just look at cost and benefit, but instead are forced to also examine how much money the powers that be will fork over. And it might be easier to fund a manned lunar mission costing 20 times what an unmanned one would to do the same science, simply because it is a better political sell. And push come to shove, there are some advantages of having humans there. But I think the benefit in advanced exploration of unmanned missions may be overshadowed by a lack of willingness to fund it.

The case of Mars is trickier, because the presence of humans would actually degrade the science at this point (in terms of astrobiology). What I would like to see is an army of unmanned rovers imaging the surface and collecting samples for return, as well as in situ analysis, that were controlled in real time by astronauts in Mars orbit, to avoid the troubles of the radio lag to earth. However, given the extremely high cost of this and the political problems of selling coming so close and not touching down with humans, I think the chances of this happening are about as good as Bush coming on television tomorrow to announce that the U.S. will begin unilateral nuclear disarmament beginning immediately.

[quote=Bob Shaw,Sep 9 2005, 11:57 PM]
Certainly, seeing a cleaned up version of Apollo 15 video (and prior) would be fun... ...and *better* than Michael Light just sets me dribbling...

It burned me up that the best scans of Apollo photography were in private hands unavailable to the public. Light, and National Geographic scanned low generation material which sits in their archives treated as their intellectual property and doled out only as secondary products of selected and expensive nature.
Some slightly flawed scans of low generation material were made a couple years ago by JSC which appear on Kipp Teagues Apollo archive page. (all of which had a silouette of a hold down clip extending into one side of the frame, cropped or 'cloned' out in the on line versions. One example of such a scan can be found here:

http://www.hq.nasa.gov/office/pao/History/...1-44-6609HR.jpg

note the lack of overexposed burned in sunlit regions common to later generation material as well as the detail in the shadows from scattered light from the surroundings!

Mark Gray of Spacecraft Films has done a classy series of DVDs from 16 mm film in the National Archives as well as all the video made from the vicinity of the Moon. I believe something like 75 percent of the Lunar Surface video survives, the rest is preserved only in inferior 'kinoscope' 16 mm film made from a television monitor just as television programs were preserved before the days of videotape! Unfortunately, so I'm told, NASA did not archive the best quality video tapes of most of the missions, even Apollo 11. The best recording of the ratty, ultrasound looking Apollo 11 material is probably the NBC material which was televised in real time on an 'As It Happened' program which I have on VHS. Television networks have in some cases the only one inch tapes of whatever scraps of the various missions they decided to televise and then archive, and they are very tight fisted.
I hear that only the last 2 or 3 missions have consistantly good video masters in the hands of NASA, which fortunately coorisponds with the best quality video transmissions. The Apollo 14 video in particular is horrible thanks to a defect in the camera which made anything brighter than the Moon 'bleed' into its surroundings. There is not much one can do to 'clean up' the video material, although Apollo 17 seems to be the best quality of both the original material as well as the state of preservation.

Don

I really think such a project to scan the material should be undertaken, and it should remain public domain. I think the same stance should be taken here as with dealing with the lunar samples, and private ownership of the raw data should be prohibited. I think that scanning has matured to the point that a scan could potentially record virtually all the data in the photographic frame. I think that this would serve the dual purpose of supplying the public with the data it paid for and protecting the data, as the more copies that exist, the less likely it will ever be lost.

In the past, it's prohibitively difficult to distribute large film scans in high definition. With the impending arrival of blu-ray and other tens of gigabyte disks, such images can be feasibly distrubuted without data loss.

Could not agree more. Light's book made a big deal about how the images were 'cloned' however because he was only granted access to the master dupes the images are still a copy of a copy. Image scanning techniques and data storage and distribution has has matured to the point that the shape of the individual grains of negatives can be resolved producing a 'true' clone of the image. I too agree that it is time that true clones of all the apollo imagery was generated from the master negatives.

If NASA wants to generate public support for a return to the moon or mars there are few things that would generate more publicity than a 'For All Mankind' archive of apollo imagery availbale on the internet.

Can you imagine what this community could do with the digitised, cloned apollo imagery, i'm salivating just thinking about it.

I have always wondered if the moon-hoax folks were at least somewhat influenced by the fact that NASA reproductions often look so washed out that they really do look like they were taken in a hazy atmosphere.

I think that two kind of lunar missions would be possible at a reasonable cost and with an interesting science return, making things really advance since the Apollo era.

1) a very low orbiter, just high enough not to hit some mountain (3-5kms high) with accurate imagery system, underground radar sounding, infrared minerals identification, etc. similar to what is used on Mars today, but shooting at blank-point on the Moon (and much less expensive, without the interplanetary travel).


2) A large rover, with caterpilars or extra-wheels, and a complete science lab including remote-controlled micro-manipulators to isolate very small samples of crystal/minerals, and examine them with the best science instruments: polarized light, microscope, neutronic activation for isotopic research, radioactive datation, gas analysis, X-ray analysis, etc. Such a rover would be able to rove say, not 5kms, but thousands of kms, like any other vehicule on Earth, and so it could visit a large variety of sites on the visible hemisphere. It would need years to visit all the sites, but in the average it would require only a very small team to remote-control the drive 24h/24 (in place of depending on satellite passes like on Mars)


Human missions on the Moon? I think that for this we need some very good reason. Not bad sci-fi reasons like excavating all the Moon surface to obtain helium3 (which would require more energy than it could produce) but a science-worth and psychologicaly/politicaly motivating purpose for gaining support from the general public opinion. (The first condition is being international)

How long could such an orbiter function before it crashed into the Moon? IIRC low lunar orbits are dangerously unstable.



What about a mission to the far side? You'd need a satellite to relay back information from there. If you are doing a mission with multiple rovers, I'd think at least one should be on the far side -- which remains something of a terra incognita.

How long as there remains fuel to stabilize it, and as short as we want to be close of the surface. This is a classical trade off discution.







Yes, why not, the same rover could do, but it would need a relay, say on a stable Lagrange point of the Moon, or looping around the farthest unstable point, or in orbit. We could eventually operate the rover for years on the visible face, and later send a relay to obtain ability to operate on the hidden side. Anyway an efficient relay is the first prerequisite for any serious Lunar operation, we see with Mars how sustained activity depends on availability of radio link and satellite relays.

I think there are perhaps more interesting science data on the hidden face. On the visible face one of the most worthy point would be in one of those places in the "seas" which were not covered by lava flows, but have been stripped of regolithe in the impacts which formed the seas, and exposing the most ancient hard layers.

I meant to ask also about the power situation on the moon; obviously, power would be available and plentiful during the daytime, but with current technology could a rover store up enough power to keep operating during the lunar night? If so, what would it do? If not, could both the mission and the rovers survive through two-weeks on, two-weeks off cycles of observations?

The problem is that the Moon is not perfectly spherical, its center of mass is not in the center of the physical body, and its gravitational field is notoriously lumpy.

A spacecraft in a 100km orbit requires orbital adjustments to avoid crashing once a month or so (such an orbiter, in such an orbit, with no propulsion system lasted about six weeks). At the altitudes you're speaking of, Richard, you'd have to adjust the orbit every few revs. You'd have to put *way* more fuel than spacecraft into lunar orbit if you wanted to try this. And if you want a low circular orbit, you have to settle for something no lower, on average, than about 20 km, because the Moon's off-spherical and mass-center status would literally crash a spacecraft in a 5km orbit after about half a rev.

Now, if you want to have a lunar orbiter in an elliptical orbit with a high apocynthion and a very, very low pericynthion, that's easier to do -- but you only get really close passes over a small, small fraction of the surface. And you can only stay in such an orbit for one or two revs before it crashes you.

Yes, it's a classic trade-off, but a very, very bad trade-off when it comes to the engineering of the task.

-the other Doug

I was 13 years and nine months old when Apollo 11 landed on the Moon. I was 17 years and two months old when Apollo 17 landed. (Interestingly, I was 15 when Apollo 15 landed, 16 when Apollo 16 landed, and 17 when Apollo 17 landed.)

It was inconceivable to me that I might never, ever see human beings walking on the Moon again in my lifetime.

Now, the inconceivable is the most likely -- and it deeply depresses me. The best and most amazing thing we, as a race, have ever done happened when I was a teen-ager.

And now we don't do it anymore. And likely won't ever do it again in my lifetime.

As a lot of other people have said, I will believe we will return to the Moon when I see it. I've had my hopes raised too many times, just to be dashed against the rocks.

I guess you could say it's a sore subject with me...

-the other Doug

Tedstryk, It is certain that the only focus on cost/benefit does not work in some cases where there is play of political/influences. I haven't tought of this. You are right. Put a man on the moon and will incite the public to approval to goverment to fund more money to space programs....

Dvandorn, don't worry that the man will not come back to moon. I bet that before than 2010, a man will be traveling around the moon. I guess the ones will be a venture private company who will send 2 or 4 billionaries tourists to the most exoctic trip : Moon.

Now, about touching the moon floor, it is a matter of the fact of political influence for what??? Prepare a man for a mission to Mars... I think it would be a long term if the world problems are in well under control: Vietnam war versus Apollo, now ....(Iraq war, Katrina hurrican, others) versus manned space flights. These late factors might influence to postpone the space programs.

However, now the other important force is the technology which is making easier to send a man to moon: cheaper and safer spaceship to send man to moon as a "tourist". Less than one month, I have heard a private company along with a Russian space company are promoting a trip to moon before than 2010. To land moon would be after NASA, of course due to the higher logistics cost (more combustion, platform), have set up a Moon base.

I don't think that Japan will make effor to send man to Moon but yes to chinese goverment because I think that the Chinese goverment needs to send a man as political reason (like to U.S. during his race agains Soviet) in order to rise the pride as new super power nation.

Rodolfo

Don Davis: "I hear that only the last 2 or 3 missions have consistantly good video masters in the hands of NASA, which fortunately coorisponds with the best quality video transmissions. The Apollo 14 video in particular is horrible thanks to a defect in the camera which made anything brighter than the Moon 'bleed' into its surroundings."

That's strange, because I watched all of the two Apollo 14 moonwalks live, and the TV struck me as being very good. Of course, it may just have seemed that way by comparison with what had gone before...

As for the odds of our actually lanbding men on the Moon again any time in the reasonably near future, take a look at NASA's (leaked) internal charts on the cost profile of doing so by 2018: http://www.spaceref.com/news/viewsr.html?pid=17989

We're talking about -- at least -- doubling NASA's budget. Ain't gonna happen.

Apollo 11's lunar camera was black-and-white (interesting note: it was a CIA-built article!). Apollo 12 had a color camera, but in setting the camera up on its tripod at the beginning of the first moonwalk, they accidentally pointed it at the sun and burned out the camera! I remember that NBC TV still covered the moonwalks - using marionettes to accompany the audio feed! That had to have been the only time puppets were used on to cover live national news!

My dad bought our family our first color TV specifically so we could watch the Apollo 12 moonwalks in color.

Have you seen the book "Virtual LM"? Scott Sullivan did a beautiful deconstruction/ reconstruction of all the lunar module's structures and systems. It is hard for me to imagine us building anything like that wonderful ship again.

I remember that, also. However, I do recall way earlier that NBC used a Bill Baird puppet (a little silver space suited astronaut puppet, moved using thin black sticks like muppets) to try and cover a Gemini EVA, since there was no live TV. The EVA was where the astronaut went to the back of the craft (the big white adapter section of the Gemini) to test using some tools stored there in a tool box. The puppeteer tried to listen to the air-to-ground com in order to choreograph the puppet action to what was being said. Needless to say... with the early com available only when over ground stations (no TDRSS), and very scratchy and garbled, it didn't really work out very well. The puppet seemed a bit "lost" most of the time, not knowing what to do.
I do recall where the puppet was in the back section at the tool box (since he was following the timeline), but then heard on the com that the astronaut was really only halfway there. Because it was live with no "cutaways", the poor puppet had to scurry back out to where the astronaut really was!

I also remember the early Gemini-Agena dockings, where NBC again tried some innovative (but now, laughable) stuff: They had an HO scale model train track set in a huge circle, and another track that gradually spiralled out to this large "orbit". A motorized wheelset carried a model of the Agena on the outer orbit round and round. Another motorized set carried a Gemini model on the spiral track until it reached the switch track onto the final "orbit". Then, finally, they would "dock" (i.e., one would run into the other!). Even back then as a kid, I thought it was a pretty idiotic way to illustrate the concept.

Let me try again...;-)

That's strange, because I watched all of the two Apollo 14 moonwalks live, and the TV struck me as being very good. Of course, it may just have seemed that way by comparison with what had gone before...

If you examine the Apollo 14 video and then compare it with the later missions, particularly Apollo 17, you will notice an awful 'blooming' of anything brighter than the lunar surface which tended to give the image a defocused effect like that of 4th generation amateur dupes of a bad VHS tape. This was due to some issue with that camera which was fixed by the next mission. Each later flight seemed to have a small improvement in the video quality and signal handling thereafter but the jump in color camera quality was most noticable between 14 and 15. The problem was recognized by mission control just after it was set up pointing at the LM and some minutes were spent trying to adjust the iris to let in less light to see if it helped, some marginal improvement was seen when the settings were brought down so the Moon looked very dark but the TV camera adjustments were taking too long and they left in in an overexposed setting which exaecebated the defects in that camera.
All the Apollo color cameras used a bandwidth saving 'sequential color' system with a little spinning RGB filter wheel which used each group of three sucessive grayscale frames to make a color picture, of fairly good color fidelity as long as things didn't move too fast in the frame. I wish more 16mm real time material could have been captured, the apollo 16 sequence nearly looking into the sun of the astronaut going down the ladder is stunningly good compared to any of the video, and film cameras are not killed by pointing them toward the sun!

The Apollo disks from spacecraft films are excellent reference material, and are probably the means in which the videos will survive at all once the cities where the archives are kept are destroyed in some future war.

Don

The problem with the Apollo 14 camera was in its electronics, although it was using a different vidicon coating than had been used on the three earlier color cameras developed for Apollo.

The first color camera was put together just barely in time to fly on Apollo 10. That same camera was re-flown on Apollo 11, although a back-up camera had been built by the time 11 flew. The first camera was used inside the CM only on 10 and 11.

After Apollo 11, the in-cabin camera used on 10 and 11 was re-packaged and mounted on the LM descent stage for Apollo 12. It was the camera that was burned out by being pointed into the sun. Apollo 12's CM camera was the back-up developed for Apollo 11.

The camera on the Apollo 13 LM was identical to the cameras previously flown in terms of vidicon coating and electronics, but it was never used. (Careful use of a lens cap was to protect it from direct sun-imaging burnouts.) The camera on the Apollo 14 LM was of the same design, but had a new and different type of vidicon coating that made it less susceptible to damage from direct sunlight (although they still used a lens cap).

The real problem with the Apollo 14 camera was a bad component in the peak light control circuit. Instead of making the video signal balance to the peak lighting elements in the scene, it exaggerated peak lighting elements. The quality of the images from that camera when it was opened up all the way (biggest aperature), at the beginning of EVA-1 when it was looking into the shadow of the LM at the foot of the ladder, was actually quite good -- except that the sunlit surface beyond bloomed up and made the descending astronauts look like they had little tiny stick legs. But when Shepard came close to the camera as he took off the MESA blankets, the detail on his visor assembly and RCU was quite good.

Image quality was poor but acceptable when the camera was looking cross-sun. But when they set it up looking down-sun (during the ALSEP deployment from the SEQ bay and, later, during the setup of the ALSEP), the crew and their equipment were nothing more than big white blobs. It's a shame, since this was the only time the deployment of the ALSEP from the SEQ bay was televised or filmed, and the images are of extremely poor quality.

The glitch in the peak lighting circuit resolved itself somewhat by the beginning of the second EVA, and the images during EVA 2 were better. But since a vast majority of EVA 2 was spent with the camera pointed at the wrong segment of Cone Ridge to see any of the traverse, it really made no difference to the overall poor taste the Apollo 14 camera left in the public mouth.

I sort of wish they had gone to Plan B, which had been part of the planning on both Apollos 13 and 14. On both of those missions, the LM actually carried a back-up TV camera, a black-and-white camera identical to the unit used on the surface during Apollo 11. It was strapped to the side of the LM and covered with a thermal blanket. If the color camera was burned out on one of these missions, the crew was supposed to replace it with the B&W camera. I sometimes think the B&W camera would have given better pictures during EVA-1 than the color camera did.

On the J missions, of course, they used a much better color surface camera, capable of generating 525-line (NTSC-compatible) output. It still used the sequential field color wheel system, but it had a much sturdier vidicon coating (those cameras got pointed directly into the sun several times and never suffered a problem). Those cameras provided near-studio-quality video from the Moon during those missions -- a vast improvement over anything we saw during the first three landings.

-the other Doug

Yes plenty of energy by day (with no dust as on Mars) but not so much: if you take a martian MER and make it, say, 5 times larger, the power gets 25 times larger (the surface of the solar panels) but the mass gets, say 125 times larger. We gain only from the lower gravity of the Moon, and from a 24hours solar exposure (by day).

By night, save using a RTG, there can be only a small amount of energy from a battery, to keep alive some basic electronics or long integration from science instruments (for instance analysis of radio-isotopes). Anyway driving by night on rugged terrain would require extensive lighting, consuming much more energy than by day, and not within reach of a RTG. So we must do with this limitation, and skip night drives. Anyway a lunar day of 24h/24 driving session may allow to drive hundreds of kilometres, so roving the entire Moon in the rover lifetime is feasible. Also the experience of the MERs (with deep sleep) tells us that electronics must be prepared to withstand the lowest temperatures, in case of a failure of heating. But if it is so, we do not need heating at all when this electronics is not used. And by day there is plenty of sun heat.

Yes, I did not realized that it was so tricky. I based my rough guess on the Apollo orbits, which were, if I remember well, 10kms high, but were used only some days. To manage such a scenario, you have two solutions:
-stay on a safe orbit, but less interesting
-manage several closer encounters on a fuel budget basis.
On the other hand, raising or lowering a Moon orbit of some kilometres requires much less fuel that on Earth, so the thing may be feasible, that depends on the fuel required.

Note that a radio relay satellite is not concerned, as it works better at much higher altitudes.

Once again, watching it live I didn't think the coverage of the ALSEP being unloaded from the SEQ bay was all that bad. And the impression I got during EVA 2 was simply that they had walked too far off into the distance for the camera to see them -- certainly it kept them in view until they were quite a long way from the LM. But, again, this may simply have been a function of the fact that the TV from the first two landings was so remarkably lousy. In any case, I simply do not understand Don's comment that the Apollo 11 camera would have done a better job -- there's no comparison!

I very well remember the Apollo 12 TV fiasco -- I sat up in the middle of the night to watch the damned thing! And, thanks both to Al Bean (who later claimed that he didn't KNOW the camera would fail if aimed into the Sun, although I knew it at age 15 without being all that well-informed) and the fact that the crew forgot they were supposed to switch to color film for their closeup photos of Surveyor 3, we have NO color views of Surveyor 3 on the lunar surface except for a few long-range, almost invisible views of it in the Hasselblad panoramas taken from the LM during EVA-1. Bah. It would have been nice if that crew had spent less time working on practical jokes and more time on what they were supposed to do. (Although I do note that Don Wilhelms, in "To A Rocky Moon", has a higher opinion of them than of Alan Shepard.)

The standard Apollo CSM orbit was circular at about 100 km (about 70 statute miles). The so-called descent orbit, from which the LM began its descent near the low point, had an apocynthion of 100 km and a pericynthion of about 7 km (50,000 feet, or roughly 9 statute miles).

During the first two landings, only the LM went into the descent orbit, and it only stayed in that orbit for half a rev, until it started down to the surface. The CSM stayed up in the 100-km circular orbit. However, beginning with Apollo 13 (and actually implemented beginning with Apollo 14), to save LM fuel, the plan was changed to use the CSM's engine to place the entire CSM/LM combination into the descent orbit, starting with the LOI-2 burn. The burn that used to place the whole craft into a circular orbit was changed to place it into the descent orbit. And so, NASA started putting their Apollos into the descent orbit for more like a full 24 hours and not just an hour.

What happened? Well, on Apollo 14, not much -- the CSM circularized its orbit just before the LM came around to land, no problems. But on Apollo 15, the CSM/LM descended from a low point of 50,000 feet down to a low point of 33,000 feet while the crew slept the night before the landing -- all due to the Moon's lumpy gravity field. Since there were mountains on Apollo 15's approach path that reached up nearly 15,000 feet, this was dangerous, so the crew performed a "bail-out" burn early on landing day to raise the orbit's low point back up to 50,000 feet.

That happened because Apollo 15 flew directly over Serenitatis and Imbrium, two areas with localized positive gravity anomalies (mass concentrations, or "mascons"), which pulled its orbit down at the low point. Apollo 16, which overflew the gravitationally-blander equatorial regions, had no real problems. But Apollo 17, which was also to overfly Imbrium and Serenitatis, had its plans changed. The low point on its original descent orbit was only 80,000 feet, not the 50,000 used on previous missions, and the LM used its RCS jets to lower the pericynthion to 50,000 feet just half a rev prior to landing. This was partially to keep the orbit from degrading due to mascons, and partially because the Apollo 17 landing site was rather far to the east, and there was little time after acquiring the spacecraft to track it and ensure that its low point would not intersect the lunar surface. So they decided to risk only the 80,000-foot pericynthion for the entire spacecraft. As I recall, that orbit also decayed, though not as much as Apollo 15's did -- down to about 70,000 feet by the time landing rev came along.

So, depending on where the low point of an elliptical orbit overflies, a lunar orbit with a low point much under 20 or 30 km is stable only for a matter of days. However, Apollo 16, which had little problem with their orbits deforming badly over the course of a few days, left a small sub-satellite in orbit behind it, in the standard roughly circular 100-km orbit. And it crashed six weeks later. Therefore, low lunar orbits simply are not stable over time and must be constantly monitored and corrected, at an expense of a lot of fuel...

-the other Doug

My understanding from post-mission analysis --As I recall!-- was that the Apollo 14 lunar surface camera overheated during the EVA and progressively defocussed. This is entirely separate, I think, from the blooming and gain problems discussed above. As the EVA toward Cone crater proceeded, the image slowly deteroriated, perfectly adequately exposed parts of the scene getting blurrier and blurrier. I'd have to check and scan my 35 mm slides off the TV to cross check what I actually saw, and/or get Spacecraft Films dvd's of the mission.

Does anybody have an idea how low an orbit could be kept stable by using an ion engine to "tweak" it?

tty

[quote=BruceMoomaw,Sep 11 2005, 11:15 AM]
. In any case, I simply do not understand Don's comment that the Apollo 11 camera would have done a better job -- there's no comparison!

I think you mean the comments of 'The other Doug'
"If the color camera was burned out on one of these missions, the crew was supposed to replace it with the B&W camera. I sometimes think the B&W camera would have given better pictures during EVA-1 than the color camera did."

And so far as resolution of detail, even through the noise, he may well be right. That's not saying much, but I remember a sense of mystery some expressed somehoe emphasizing the faraway marginal nature of the undertaking. One wonders if signal strength and other factors were optimised what the full capabilities of such a camera might have been. I recently read it was capable of a higher resolution slow scan mode which was never used.
When the film was returned and developed it looked unbelievebly clear in comparison, as it it were from a different event. I am admittedly comparing A14 TV with the later missions, not the earlier ones which is certainly a glass full-empty thing, but in the end it was simply one step in improvement in lunar surface video which continued each mission.

Don

Thank you for detailed info.

That fuel is needed to maintaing the orbit is what I meant. We could see how energy consumption increases with lower altitude and decide an altitude. The lower the altitude the shortest the mission. So this is not suitable for a permanent lunar observatory, which may need, after your info, to be at least at 100kms. I just have a strange idea: to use the mascons as a gravitationnal assistance, so that they help to maintain the orbit. This would require less fuel.

May be this could be the solution for a low altitude lunar orbiter.

The problem with lunar orbit is rather different than with an Earth orbit. Around Earth, satellites lose ebergy due to air braking. So their orbits become more circular, and lower. Around the Moon, there is not such a loss of energy, but the action of the masscons makes the orbit more and more elliptic (it is what I conclude from above) until the lowest point touches a mountain.

So we do not need a constant action, but a correction which would at times act to accelerate the orbiter, at times to brake it, in order to keep the orbit circular.

Would a ion engine do better for this job? At first it must be orientable. At second, its thrust is very weak, compared to chemical rockets. But they are better in the long run, as they can thrust all the time. So they could perform better for a mid-altitude orbit. But could they correct the 5km discrepancy experienced by Apollo 15, on its 15kms high orbit, in only half a revolution? (see above post by Dvandorn) I think it is useless to disscuss, things must be calculated.

What is the acceleration required to, say to give an order of magnitude, shift of 5kms in half an hour? From the well known formula x = gamma T2 /2, I return an acceleration of 0.003 m/s2. For an orbiter of one ton, it requires a thrust of 3 newtons. Is this within the capacities of a ion engine? And for how many time? ("fuel" consumed).

It would have to be a lot more powerful than the one on SMART-1 or the one on DS-1. Whether or not it can be done, I don't know.

The size of your batteries (assuming a straight scale-up) would also increase by 125. But, the moon is much closer to the sun with less seaonal variance than Mars (More than double the solar radiance, I think). If you're going to build a big rover like that, I would also add solar panel tilt mechanisms to maximize power.

But I'm not sure a 5x larger every dimension rover would be necessary, maybe 1.5-2x.

One possibility, if a lunar relay orbiter could be put up, would be to race the sun by landing on the eastern edge at sunrise, and race west as the sun rises. An average speed of 15 km/h west (at the equator, away from the equator the speed decreases) should be enough to keep up, and since you land during sunrise, you could spend up to two weeks doing stationary science. Faster speeds would allow for more science, of course. I would land in the mid-latitudes intially, spending mroe time doing science, and then in an extended mission do a "moon peeler" going around and around until the wheels fall off...

To race the sun, very good idea. As a matter of facts, the equator of the Moon moves at about 16km/h, and higher altitudes are still slower. So it is not unthinkable to race the sun (on Earth this can be done only by supersonic aircrafts) with a rover, if we alway move toward the West. But in this case a satellite relay is mandatory, as we shall spend half of the time on the hidden side. Such a race would require a permanent 24h/24 community of scientists/drivers to keep the rover moving, and stop it immediatelly when interesting spots are in view. Also science sampling, photography, etc, should be done in a short time, to keep the pace at 16km/h average, and the samples stored and studied later during drive. Even if we do not achieve a permanent race, the ratio day/night or active/inactive would increase significantly, and it is not to neglect.

About the size and weight, if there is more science instruments, there is more weight. Add to this manipulators, hammer and saw for breaking stones, etc, the basic stuff of geology. But what we need also are much larger wheels, from the experience with the MERs. There are no dunes on the Moon, and the surface is generally smooth, but there can be tricks like large rocks and small but steep craters. We could also seriously consider... spare wheels, in case one os stuck or broken. From where the extra-size. But we were able to land the Apollo ships which weighed 16 tons, so be compared to the Martian MERs which weigh only about 70kgs, this makes possible a 6 times larger rover.

Solar Irradiance is going to be the same as the baseline at 1 AU which is 1367 Kw/m^2. The lack of an atmosphere has pros and cons. The main pro is that there is no atmospheric loss for direct beam irradiation but that also means there is negligable diffuse irradiation so a Sun tracking panel would be very desirable. A second plus is that the Lunar surface environment is similar enough to earth orbit from a spectrum\temperature\vacuum point of view that you could use "standard" Earth Orbit types of cells rather than those optimised for Mars (Low Intensity\Low temperature\Red wavelength bias).

For a MER type 1.2m^2 panel of GaInP\GaAs\Ge improved triple junction type cells with 26.8% efficiency you'd get 366W continuous power, that's about 9x the available power per day that the MER's produce with the same array, provided you manage to implement an effective sun tracking mechanism.

The main drawback though is Lunar dust and its very very nasty behavior. It's much more abrasive than Martian dust and the Apollo missions learned that it nasty in all sorts of other ways - it's highly adhesive for one thing and with no atmosphere it travels in lovely parabolic ballistic arcs. A rover hitting 15km/h will throw rooster tails _at least_ 5m in height. effective dust guards around the wheels would be absolutely required but they would severely penalise mobility. Even so any fast moving rover on the moon will be a moving dust cloud generator which is not a good thing.

I love the idea of a sun chasing lunar rover but I don't thing it's a runner.

Yes lunar dust... Why is it so adhesive? From static electricity or otherwise? Solar panels should be made antistatic, but this will probably not be enough. And we do not have dust devils... We could wipe the dust out of the solar panels, but if it is abrasive, this would quickly destroy them. Unless we made their surface diamond hard. The only idea I have right now is rolling some chewinggum-like material on the panels to gather this dust. But this makes additionnal hardware... Or to, from times to times, disconnect them from the main bus and take them at a very high voltage, hoping to chase the dust away.

A high speed is however required if we want this machine able of reaching distant spots on the Moon.

This "essay" I found seems to give a fairly simple explanation (as well as an interesting (but one sided) summary of the debate on what the Lunar surface was like prior to the Apollo landings). What seems universally agreed now though is that at least for the first 10-15 cm of surface it's very fine dust and without any atmosphere the small scale attractive forces between particles (van der waal's force I think it's generally called) are sufficient to cause particles to adhere with only a single point of contact. I also suspect that while these forces are similar to electrostatic forces they can't be negated by charging the body the dust is adhering to but I'd welcome any comment that would prove that wrong.

The comment that the Apollo equipment that are now in various museums are still covered in dust despite repeated cleanings backs up other reports I've read that Lunar dust is nearly impossible to clean off. I'd be interested to find out if any one reading this who has seen any of the returned Apollo equipment up close can verify this.

My gut feeling is that dust mitigation will be a huge problem for any Lunar lander but especially so for any rovers, much more so than Mars. My reading of pre-MER papers leads me to suspect that while dust deposition on Mars is a problem, Martian dust has turned out to be much less of a problem than expected, possibly because the conventional wisdom prior to the MER experience was heavily influenced by people who had ground truth data from the moon where the dust really is a killer.

The dust is even more nasty when you consider that any mechanical solution to cleaning the dust is itself going to be badly affected by it. Do we have any info on any planned Lunar rovers? It seems surprising to me that in a quick search on line I can find nothing substantive about any future plans apart from some fairly flimsy PR stuff about a commercial venture from 96\98 by a company called Lunacorp.

Yes, it was also my impression. Van der vaals forces can become very strong when particles are small. Static electricity is not implied (the particles do not need charge to adhere) but the force is basically an electric attraction between the electrons of an atom and the core of another. And on the Moon, there is nothing like rain to wipe away dust.

This is perhaps the reason why there was no project of lunal rover, however it is one on the first things to do (wether it is manned or not).

So the hardest blockage may be the problem of dust adhering everywhere on solar panels, camera lenses, portholes, etc. A possible solution would be to use fluorinated materials (teflon-like) for all the critical surfaces, with the hope that no dust can adhere on them. Wipers are the most light-weight mechanical solution, but they may be inefficient with dust adhering from Van der Vaals forces. Perhaps electrostatic wipers may do the job (passing over the surfaces without touching them) while being themselves easy to clean mechanicaly.

So from this discution it appears that this problem of dust is to address in priority into the design of any rover more ambitious than the slow MERs.

Well, the Soviet rovers survived the lunar night just fine, with top speeds of 2 km/h:

http://pages.preferred.com/%7Etedstryk/lunokhod2.html

I don't think the dust is as big a deal if you only have one moving object, since you know where the dust is going to be and you don't have astronauts kicking dust all over your nice clean rover. Any rooster-tails could easily be confined to under the rover, or even ducted to point rearwards.

I see it as a very tough mission for rovers to keep the rover in a sunny area.

The moon circunference distance is = 2*Pi*1734.4 km= 10,916.43 km

Half Moon is 10,916.43/2 = 5,458.22 km
The lenght of Moon day is 27.321661 Earth days

The minimum velocity to keep the same 90 degree to the sun position is =
10,916.43 km/(27.321661 days*24 hours/1day) = 16.65 km/h

I see that by keeping an average of 17 km/h is a very tough mission for a remote controller. This is unpractical idea since the rover must stop as often as possible, if not it is not worth at any way, on its way around the moon for science, geology and others...ogy explorations.

I agree that the moon is very dusty and hence, the solar power must have somewhat technology that is capable to keep away the dust. A compressor or air blower won't work at Moon (airless environment).



Why is necessary to have a spare tire at Moon? Will anyone help to change tires? You know that all Moon and Mars rovers's wheels are made of aluminum.

I think the most practical ones is ones alike to MER-A and MER-B. Both are separated at the 180 longitudinal degree. So, it is needed to send two Lunar Science Laboratory (LSL) at 180 longitudinal positions and it will keep the rovers and team working in 24 hours with the support of Lunar Recognizer Orbiter (LRO) Well, the idea to work for 24 hours have no good support unless if there is some urgency.

Finally, the most probably next landing mission would be at the Poles...The rover will be traveling at even lower speeds, perhaps, 20 meters per day like MER...

Rodolfo

Nobody spoke of tyres! I know how are the MERs wheels. But a large wheel will not be machined from one block, it will feature springs, spokes, etc which can break, or the whole whell can stay stuck between two rocks. From there the interest of spare wheels. Of course if we do so, we cannot remove bolts and change the wheel like in a car garage; there must be arms bearing the wheels (like of the MERs) and if needed this arm is severed and another comes into position. Or the rover has 8 wheels. Anyway if one is lost the capacities are lowered.

As to driving at high speed, not the first day. But when you will have analysed all the random blocks around, you will have to look for another target. And this target can be very far (for instance the Apollo landing sites were thousand kilometres appart) From where the need for speed, especially into the blank voidness of the immense Moon oceans. With, of course, a team of geologist rewieving the video images in real time, in case if something interesting shows up.

Of course really keeping the pace with the sun wll be difficult; but at least if we do not achieve this, we can still achieve a longer day/night ratio in alway running westward.

Ted,

Scans of several original Apollo film magazines can be found at www.apolloarchive.com. "A11-40" was the first magazine to be scanned in 2004, coinciding with the 35th anniversary of Neil's first step. This roll covers the entire Apollo 11 EVA.

Since then, many other Apollo magazines have been digitally scanned by Johnson Space Center and sent to Kipp Teague in TIFF format. After extensive processing and conversion to the JPEG format, he makes the images available to download from his website.

http://www.apolloarchive.com/apollo_gallery.html

Regards,

Ian.