Posts Tagged ‘moon’
In 2009, a poll held by the United Kingdom’s Engineering & Technology magazine found that 25% of those surveyed did not believe that men landed on the Moon. Another poll gives that 25% of 18- to 25-year-olds surveyed were unsure that the landings happened. There are subcultures worldwide which advocate the belief that the Moon landings were faked. By 1977 the Hare Krishna magazine Back to Godhead called the landings a hoax, claiming that, since the Sun is 93,000,000 miles away, and “according to Hindu mythology the Moon is 800,000 miles farther away than that”, the Moon would be nearly 94,000,000 miles away; to travel that span in 91 hours would require a speed of more than a million miles per hour, “a patently impossible feat even by the scientists’ calculations.”
From ‘Moon landing conspiracy theories’ , Wikipedia
Haha just for the record the Sun is nearly 400 times further from us than the Moon, but who’s counting? So now to the Apollo moon missions, and because I don’t want this exploration to extend to a fourth part, I’ll be necessarily but reluctantly brief. They began in 1961 and ended in 1975, and they included manned and unmanned space flights (none of them were womanned).
But… just one more general point. While we may treat it as inevitable that many people prefer to believe in hoaxes and gazillion-dollar deceptions, rather than accept facts that are as soundly evidence-based as their own odd existences, it seems to me a horrible offence in this case (as in many others), both to human ingenuity and to the enormous cost in terms, not only of labour spent but of lives lost. So we need to fight this offensive behaviour, and point people to the evidence, and not let them get away with their ignorance.
The Apollo program was conceived in 1960 during Eisenhower’s Presidency, well before Kennedy’s famous mission statement. It was given impetus by Soviet successes in space. It involved the largest commitment of financial and other resources in peacetime history. The first years of research, development and testing involved a number of launch vehicles, command modules and lunar modules, as well as four possible ‘mission modes’. The first of these modes was ‘direct ascent’, in which the spacecraft would be launched and operated as a single unit. Finally, after much analysis, debate and lobbying, the mode known as Lunar Orbit Rendezvous (LOR) was adopted. The early phases of the program were dogged by technical problems, developmental delays, personal clashes and political issues, including the Cuban missile crisis. Kennedy’s principal science advisor, Jerome Weisner, was solidly opposed to manned missions.
I can’t give a simple one-by-one account of the missions, as the early unmanned missions weren’t simply named Apollo 1, 2 etc. They were associated strongly with the Saturn launch vehicles, and the Apollo numbering system we now recognise was only established in April 1967. The Apollo 4 mission, for example, is also known as AS-501, and was the first unmanned test flight of the Saturn 5 launcher (later used for the Apollo 11 launch). Three Apollo/Saturn unmanned missions took place in 1966 using the Saturn 1B launch vehicle.
The manned missions had the most tragic of beginnings, as is well known. On January 27 1967 the three designated astronauts for the AS-204 spaceflight, which they themselves had renamed Apollo 1 to commemorate the first manned flight of the program, were asphyxiated when a fire broke out during a rehearsal test. No further attempt at a manned mission was made until October of 1968. In fact, the whole program was grounded after the accident for ‘review and redesign’ with an overall tightening of hazardous procedures. In early 1968, the Lunar Module was given its first unmanned flight (Apollo 5). The flight was delayed a number of times due to problems and inexperience in constructing such a module. The test run wasn’t entirely successful, but successful enough to clear the module for future manned flights. The following, final unmanned mission, Apollo 6, suffered numerous failures, but went largely unnoticed due to the assassination of Martin Luther King on the day of the launch. However, its problems helped NASA to apply fixes which improved the safety of all subsequent missions.
And so we get to the first successful manned mission, Apollo 7. Its aim was to test the Apollo CSM (Command & Service Module) in low Earth orbit, and it put American astronauts in space for the first time in almost two years. It was also the first of the three-man missions and the first to be broadcasted from within the spaceship. Things went very well in technical terms, a relief to the crew, who were only given this opportunity due to the deaths of the Apollo 1 astronauts. There were some minor tensions between the astronauts and ground staff, due to illness and some of the onboard conditions. They spent 11 days in orbit and space food, though on the improve, was far from ideal.
Apollo 8, launched only two months later in December, was a real breakthrough, a truly bold venture, as described in Earthrise, an excellent documentary of the mission made in 2005 (the astronauts were the first to witness Earthrise from the Moon). The aim, clearly, was to create a high-profile event designed to capture the world’s attention, and to eclipse the Soviets. As the documentary points out, the Soviets had stolen the limelight in the space race – ‘the first satellite, the first man in orbit, the first long duration flight, the first dual capsule flights, the first woman in space, the first space walk’. Not to mention the first landing of a human-built craft on the Moon itself.
The original aim of the mission was to test the complete spacecraft, including the lunar module, in Earth orbit, but when the lunar module was declared unready, a radical change of plan was devised, involving an orbit of the Moon without the lunar module. Apollo 8 orbited the Moon ten times at close quarters (110 kms above the surface) over a period of 20 hours. During the orbit they made a Christmas Eve telecast, the most watched program ever, up to that time. Do yourself a favour and watch the doco. The commentary of the astronaut’s wives are memorable, and put the moon hoaxers’ offensiveness in sharp relief.
By comparison to Apollo 8 the Apollo 9 mission (March ’69) was a modest affair, if that’s not too insulting. This time the complete spacecraft for a Moon landing was tested in low Earth orbit, and everything went off well, though space walking proved problematic, as it often had before for both American and Soviet astronauts, due to space sickness and other problems. With Apollo 10 (May ’69) the mission returned to the Moon in a full dress rehearsal of the Apollo 11 landing. The mission created some interesting records, including the fastest speed ever reached by a manned vehicle (39,900 kms/hour during the return flight from the Moon) and the greatest distance from home ever travelled by humans (due to the Moon’s elliptical orbit, and the fact that the USA was on the ‘far side of the Earth’ when the astronauts were on the far side of the Moon).
I’ll pass by the celebrated Apollo 11 mission, which I can hardly add anything to, and turn to the missions I know less – that’s to say almost nothing – about.
Apollo 12, launched in November 1969, was a highly successful mission, in spite of some hairy moments due to lightning strikes at launch. It was, inter alia, a successful exercise in precision targeting, as it landed a brief walk away from the Surveyor 3 probe, sent to the Moon two and a half years earlier. Parts of the probe were taken back to Earth.
The Apollo 13 mission has, for better or worse, come to be the second most famous of all the Apollo missions. It was the only aborted mission of those intended to land on the Moon. An oxygen tank exploded just over two days after launch in April 1970, and just before entry into the Moon’s gravitational sphere. This directly affected the Service Module, and it was decided to abort the landing. There were some well-documented hairy moments and heroics, but the crew managed to return safely. Mea culpa, I’ve not yet seen the movie!
Apollo 14, launched at the end of January 1971, also had its glitches but landed successfully. The astronauts collected quite a horde of moon rocks and did the longest moonwalk ever recorded. Alan Shepard, the mission commander, added his Moon visit to the accolade of being the first American in space ten years earlier. At 47, he’s the oldest man to have stepped on the Moon. The Apollo 15 mission was the first of the three ‘J missions’, involving a longer stay on the Moon. With each mission there were improvements in instrumentation and capability. The most well-known of these was the Lunar Roving Vehicle, first used on Apollo 15, but that mission also deployed a gamma-ray spectrometer, a mass spectrometer and a laser altimeter to study the Moon’s surface in detail from the command module. Apollo 16 was another successful mission, in which the geology of the Moon’s surface was the major focus. Almost 100kgs of rock were collected, and it was the first mission to visit the ‘lunar highlands’. The final mission, Apollo 17, was also the longest Moon stay, longest moonwalks in total, largest samples, and longest lunar orbit. And so the adventure ended, with high hopes for the future.
I’ve given an incredibly skimpy account, and I’ve mentioned very few names, but there’s a ton of material out there, particularly on the NASA site of course, and documentaries aplenty, many of them a powerful and stirring reminder of those heady days. Some 400,000 technicians, engineers, administrators and other service personnel worked on the Apollo missions, many of them working long hours, experiencing many frustrations, anxieties, and of course thrills. I have to say, as an internationalist by conviction, I’m happy to see that space exploration has become more of a collaborative affair in recent decades, and may that collaboration continue, defying the insularity and mindless nationalism we’ve been experiencing recently.
Finally, to the moon hoaxers and ‘skeptics’. What I noticed on researching this – I mean it really was obvious – was that in the comments to the various docos I watched on youtube, they had nothing to say about the science and seemed totally lacking in curiosity. It was all just parroted, and ‘arrogant’ denialism. The science buffs, on the other hand, were full of dizzy geekspeak on technical fixes, data analysis and potential for other missions, e.g. to Mars. In any case I’ve thoroughly enjoyed this little trip into the Apollo missions and the space race, in which I’ve learned a lot more than I’ve presented here.
Jacinta: I’d like to know how we got in this position.
Canto: What position?
Jacinta: Here, on Earth.
Canto: That’s a very long story, which I suspect nobody’s really qualified to tell. But maybe we can report on the best speculations. First, in order to understand how we got here we have to understand how the Earth got here.
Jacinta: And so on, infinitely regressing. So let’s just start with the Earth.
Canto: Needless to say we don’t know all the details and there are doubtless competing theories, and new data is being regularly uncovered, but it obviously has to do with how our entire solar system was formed.
Jacinta: I’ve heard that all the heavy metals like iron and whatnot are forged within stars, like when they go supernova, but our star hasn’t done that, all it seems to produce is light, yet Earth is full of heavy elements. I really don’t get it.
Canto: I recall reading years ago a theory that the Earth was formed from an accretion of planetesimals, little planets…
Canto: Yes, but how those little things came into being themselves I’m not sure.
Jacinta: Well we have lots of rocky bits and bobs called asteroids floating about in the solar system…
Canto: Yes, but not randomly. there’s a whole big asteroid belt between Jupiter and Mars, where they’re coralled, sort of.
Jacinta: But comets are different, they seem to have their individual eccentric orbits.
Canto: I suppose the point is that they also have heavy elements, and how were those elements formed?
Jacinta: Heat and pressure, I’m guessing, so things must’ve been hugely different in earlier times.
Canto: Well, this BBC site gives us some of the latest speculations. They reckon that the Earth probably formed from planetesimals, so that’s still the best hypothesis it seems, though it’s very light on details:
The Earth is thought to have been formed about 4.6 billion years ago by collisions in the giant disc-shaped cloud of material that also formed the Sun. Gravity slowly gathered this gas and dust together into clumps that became asteroids and small early planets called planetesimals.
Jacinta: Yes, that’s extremely vague. How do they know there was a disc-shaped cloud here? How can they investigate that far back?
Canto: Well don’t forget that looking out over huge distances means looking back in time.
Jacinta: Yes but a huge distance away isn’t here. Is it?
Canto: Well it might be here then.
Jacinta: Effing Einstein. But they’re also searching for extra data on the past, like checking out meteorites, which might contain material older than anything on Earth. Can they reliably date material that’s say, 5 billion years old? The Earth’s only about 4.5 billion years old, right?
Canto: I think 4.6 billion, give or take a few minutes. About a third of the age of the universe. And here’s the thing, we’ve dated all the meteorites and asteroids we can get to and they’re all round the same age, within a narrow range of a few hundred million years. So our date for the beginnings of the solar system is the oldest date for these floating and landing rocks, which is also our date for the Earth, about 4.6 billion.
Jacinta: So is our dating system completely accurate, and what by the way are carbonaceous chondrites?
Canto: Well, yes, radioactive decay provides a very accurate clock, and these meteorites have radioactive material in them, just as the core of our planet does. All the evidence so far suggests that things happened very quickly, in terms of accretion and formation of planets, once all this heavy and radioactive material was created. Carbonaceous chondrites are a type of meteorite. They’re amongst the oldest meteorites but relatively rare – they make up less than 5% of our meteorites. I mean the ones that land here. Why do you ask?
Jacinta: I’ve heard about them as being somehow important for research, and maybe dating?
Canto: Well there are different types of C chondrites as they’re called, and some of them, most interesting to us of course, are rich in organic compounds and water. This fact apparently shows that they haven’t been subjected to high temperatures, unlike for example the early Earth. But let me return to that BBC quote above. The theory goes that a supernova explosion, or maybe more than one, created all the heavy elements we have now – iron, carbon, silver, gold, uranium and all the rest, heat and pressure as you say, and these elements swirled around but were gravitationally attracted to a centre, which evolved into our sun. This was the spinning disc-shaped cloud mentioned above, known as the solar nebula.
Jacinta: Would you call that a theory, or a hypothesis, or wild desperate speculation?
Canto: I’d call it ‘the best we can do at the present moment’. But be patient, it’s a great time to be young in astronomy today. What we need is data, data, data, and we’re just starting to collect more data than we can rightly deal with on planets within and especially outside our solar system. Kepler’s just the beginning, girlie.
Jacinta: Je suis tout à fait d’accord, boyo. I think many of the astrophysicists are looking forward to having their cherished models swept aside by all the new telescopes and spectroscopes and what else and the data they spew back to Earth.
Canto: Uhh, well anyway let’s get back to our ‘best scenario for the moment’ scenario. So you have all this matter spinning around and the force of gravity causes accretion. It’s a messy scenario actually because everything’s moving at different velocities and angular momentums if that’s a thing, upwards, forwards, sideways down, and sometimes there’s accretion, sometimes fragmentation, but overall the movement is towards coalescence due to gravity. Particles grow to the size of monuments and then different sized planetesimals, fewer and bigger and farther between. And the smaller, gaseous elements are swept out by the solar wind into the great beyond, where they accrete into gas giants.
Jacinta: Right, but isn’t the data from Kepler and elsewhere already starting to play havoc with this scenario? Gas giants within spitting distance of their suns and the like?
Canto: Well, you need liquid to spit, but maybe you have a point, but I think it’s wise not to be too distracted by exoplanets and their systems at this stage. I think we need to find an internally coherent and consistent account of our own system.
Jacinta: What about the Juno probe, will that help?
Canto: Well I’m sure it will help us learn more about gas giants, but let’s just focus on the Earth now.
Jacinta: Okay, stay focussed.
Canto: These larger planetesimals became bigger gravitational attractors, each accumulating matter until we had four rocky planets in different, sufficiently distant orbits around their sun.
Jacinta: Oh yes, and what about the moons? Why didn’t they coalesce as neatly as all the other minor rocky bits?
Canto: Mmmm, well there’s nothing neat about all this, but mmmm…
Jacinta: How many moons are there?
Canto: For the inner planets? Only three, ours and two for Mars. So the question is, how come some of those rocks, or at least three, didn’t get stuck to the bigger rocks i.e. planets, via gravity, but instead started circling those planets, also due to gravity.
Jacinta: Yes, which might be the same question as why do the planets orbit around this massive gravitational attractor, the sun, instead of getting sucked into it, like what happens with those supermassive supersucking black holes?
Canto: Well first let me talk about our moon, because the most currently accepted theory about how our moon came into existence might surprise you.
Jacinta: It was a lot closer to the Earth at the beginning, wasn’t it? So it’s slowly spiralling away from us?
Canto: Yes. Tidal forces. The moon’s tidally locked to the Earth, it’s the same face she shows us always, but let’s keep on track, it was formed in the very early days, when things were still very chaotic. A pretty large planetesimal, or planetoid, slammed into Earth, which was somewhat smaller then, and it stuck to it and coalesced with it – the Earth was pretty-well molten in those days – and a lot of debris was thrown out into space, but this debris didn’t quite escape Earth’s gravitational field, instead it coalesced to form our moon. This theory was first put forward a few decades ago, after moon rocks brought back from the Apollo missions were found to be younger than the oldest Earth rocks, and composed of much the same stuff, which came as a great surprise. But now the theory is well accepted, as it accounts for a number of other factors in the relationship between the two bodies.
Jacinta: Okay, so is that it on how the Earth was formed?
Canto: Well, yes, but the bigger question is your original one – how did we get here. And that means we have to look at how life got started here. Because we’re only up to about 4.5 billion years ago – with the moon being formed about 50 million years after the Earth. And at that point the Earth was like a sea of hot magma, hot from all the collisions on the surface, and hot from the radiation bursting out from its core. Hardly great conditions for life.
Jacinta: Well there might’ve been life, but not as we know it boyo.
Canto: I’m skeptical, but we’ll talk about that next time.