[HN Gopher] Comparing Tech Used for Apollo, Artemis NASA Missions
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Comparing Tech Used for Apollo, Artemis NASA Missions
Author : gumby
Score : 48 points
Date : 2023-12-29 18:06 UTC (3 days ago)
(HTM) web link (www.eetimes.com)
(TXT) w3m dump (www.eetimes.com)
| mattdeboard wrote:
| Dustin from Smarter Every Day posted a video last month of a talk
| he gave at NASA to Artemis stakeholders. It was absolutely
| fascinating and illuminated several lessons for any engineering
| organization's leadership. Highly recommend
|
| https://youtu.be/OoJsPvmFixU?si=dHI-_EbDzcqJc-vF
| tomkat0789 wrote:
| +1, I enjoyed that talk. He showed a diagram of the Artemis
| mission plan and said, "Does this make sense!?"
|
| He also referred to a publication NASA created after Apollo
| titled "What made Apollo a Success" which is good reading:
| https://ntrs.nasa.gov/api/citations/19720005243/downloads/19...
|
| "They gave you the playbook!" Lots of stuff that I'm glad
| somebody stood up and told the Artemis engineers and managers.
| sllabres wrote:
| I find 'rocket science' quite interesting, who not :) But my
| knowledge is limited to what can grasp from watching the
| channels discussing the topics every now and then and reading
| some of the lightweight books. (I find the design and creation
| of the space suits very interesting).
|
| Nevertheless when I saw the Smarter Every Day video the first
| time the biggest question mark for me was the number of rockets
| required to reach the moon _once_ [1] There were some other
| topics from the talk like the cryogenic refueling never done
| before [2], the orbit around the moon [3]. But for these I
| cannot evaluate who much of a problem they are.
|
| But more than eight rockets for one flight sounds a lot, even
| without expertise.
|
| [1] https://youtu.be/OoJsPvmFixU?t=1746
|
| [2] https://youtu.be/OoJsPvmFixU?t=2609
|
| [3] https://youtu.be/OoJsPvmFixU?t=1385
| Scubabear68 wrote:
| One thing I always wondered is how the hardware that compares the
| N computer's output (and fails it silent if one has a different
| result) is itself hardened.
|
| Failure of that I imagine would be catastrophic.
| sllabres wrote:
| Two links, to start your rabbit hole for today: [1] [2]
|
| [1] https://en.wikipedia.org/wiki/Triple_modular_redundancy
|
| [2] https://en.wikipedia.org/wiki/Byzantine_fault
| quonn wrote:
| I don't think that is what was asked for. The question is
| really what about the combining unit itself? And in my
| opinion the answer is perhaps that this unit is very simple
| and failure would be comparable to physical failure of the
| output wire or device being controlled.
| KineticLensman wrote:
| The 'tech' comparison in TFA only applies to computer hardware
| for the guidance computers. I'd be keen to know more about the
| engines, the fuels, the materials, the construction techniques,
| etc.
| d_silin wrote:
| With the exception of computers, most of the engineering and
| materials of 1969 and 2024 are remarkably similar.
| Animats wrote:
| There's been progress. Carbon fiber works now. Titanium
| quality is much better. 3D printing of rocket engines works
| for smaller engines. (A rocket engine is a big piece of metal
| with a lot of internal voids and channels, which is what 3D
| printing is good at.) Cutting tools are better; tungsten
| carbide and diamond are widely used.
|
| That's all non-computer stuff.
| sgt101 wrote:
| I would love to see a comparison of the properties of the
| Apollo launch systems and the current generation. My guess
| is that Starship is technically a jump ahead, while SLS is
| comparable.
| WalterBright wrote:
| I've read several books about the Apollo program. Sadly, the
| focus of those books is always on budgets, management,
| personalities, and politics. Just a few technical tidbits are
| thrown in here and there.
|
| Personally, I'm much more interested in how problems were
| identified and overcome than how The Trench was organized and
| how astronauts liked to speed in their corvettes.
| dkekez wrote:
| I would recommend _Apollo_ by Charles Murray and Catherine
| Bly Cox. It covers the program from the perspective of the
| engineers who were involved and the technical problems they
| had to overcome. The book is currently out of print but is
| available for the Kindle.
| WalterBright wrote:
| Thank you for the recommendation:
|
| https://www.amazon.com/Apollo-Race-Moon-Charles-
| Murray/dp/06...
|
| I have the book! While it's a worthy book and I enjoyed
| reading it, it is not written by an engineer or scientist
| and comes from a lay perspective. There are a few great
| tidbits in it, like how to determine the amount of fuel
| left in a tank at 0 gee, but you had to read a lot of pages
| to find those nuggets.
| trollerator23 wrote:
| I think there are a few that are more technical if that's
| what you mean:
|
| * Stages to Saturn
|
| * Digital Apollo
|
| * The Apollo Guidance Computer
|
| The last one may be too boringly technical. Some parts can be
| a slog even for me who breathe that stuff.
| TMWNN wrote:
| While NASA Administrator, Michael Griffin wrote in 2007 that the
| shuttle program had been a colossal mistake and that Apollo-
| Saturn-Skylab should have continued <http://aviationweek.typepad.
| com/space/2007/03/human_space_ex...>:
|
| >Let's assume that we had kept flying with the systems we had at
| the time, that we had continued to execute two manned Apollo
| lunar missions every year, as was done in 1971-72. This would
| have cost about $4.8 billion annually in Fiscal 2000 dollars.
|
| >Further, let us assume that we had established a continuing
| program of space station activities in Earth orbit, built on the
| Apollo CSM, Saturn I-B, and Skylab systems. Four crew rotation
| launches per year, plus a new Skylab cluster every five years to
| augment or replace existing modules, would have cost about $1.5
| billion/year. This entire program of six manned flights per year,
| two of them to the Moon, would have cost about $6.3 billion
| annually in Fiscal 2000 dollars. The average annual NASA budget
| in the 15 difficult years from 1974-88 was $10.5 billion; with
| 60% of it allocated to human spaceflight, there would have been
| sufficient funding to continue a stable program of lunar
| exploration as well as the development of Earth orbital
| infrastructure. I suggest that this would have been a better
| strategic alternative than the choices that were in fact made,
| almost 40 years ago.
| araes wrote:
| On that topic, was actually searching the Space Shuttle history
| earlier, and found this infographic somebody over at SpaceX
| made when they were pitching the Dragon Module. Actually makes
| a pretty decent case that without Challenger, and subsequent
| recoil, the Shuttle program would have actually been pretty
| awesome.
|
| At the time of crash, they were on course to be running 3-4
| Shuttles at 4 flights each every year. [1] The cadence
| afterward was a pretty massive change.
|
| [1] Shuttle Flights (circa 2010):
| https://i.imgur.com/f4sRT0T.jpg
| TMWNN wrote:
| > At the time of crash, they were on course to be running 3-4
| Shuttles at 4 flights each every year. [1] The cadence
| afterward was a pretty massive change.
|
| We have some sense of what the near-term cadence goal, pre-
| _Columbia_ , was for the shuttle from a document Reagan
| signed in 1984 that forecast 24 missions a year, maybe by
| 1988. <https://www.washingtonpost.com/archive/politics/1986/0
| 3/05/n...> By then it was clear that the shuttle would never
| come close to the every two-week launch schedule forecast
| during the 1970s (and expected, back when the first launch
| was scheduled for 1979). But yes, 24 missions a year using
| both Canaveral and Vandenberg would have helped a lot with
| amortizing launch costs.
|
| That said, that's still putting lipstick on a pig. The
| shuttle program cost $196 billion in 2011 dollars over its
| entire lifespan. <https://phys.org/news/2011-07-space-
| shuttle-legacy-soaring-o...> That's $1.45 billion per its 135
| missions. By contrast, NASA pays $55 million per seat on
| SpaceX Crew Dragon as of 2019. <https://www.space.com/spacex-
| boeing-commercial-crew-seat-pri...> It's not apples-to-apples
| because a shuttle carried up to seven people and Crew Dragon
| missions have so far been no more than four people, and a
| shuttle mission often launched a satellite, but a SpaceX
| unmanned launch costs $67 to 97 million depending on rocket
| used. <https://www.space.com/spacex-raises-prices-launch-
| starlink-i...> 7 * $55 million + $97 million=$482 million;
| let's say $500 million. And that's in today's dollars as
| opposed to the 2011 dollars for the $1.45 billion figure.
| Further, the SpaceX combination
|
| * is a far safer design (unmanned unless crew is actually
| needed, manned cabin on top of rocket and not on the side,
| escape system if needed)
|
| * can provide an astoundingly frequent cadence (just under
| 100 launches in 2023, goal of 144 for 2024)
|
| * does not yet include Starship, which if successful will
| further lower costs and increase maximum launchable mass
|
| But the topic is what Apollo-Saturn could have done if
| continued. The $1.45 billion per launch figure is based on 30
| years of the shuttle; in other words, the system has been
| optimized for efficiency as much as possible. As mentioned,
| the shuttle flew 135 times during those 30 years, for 4.5
| missions per year. Griffin is saying in 2007 that for the
| cost of maybe five shuttle missions ($6 billion), the United
| States would have had each and every year for the three
| decades from the mid-1970s, when Apollo ended:
|
| * Two missions to the moon
|
| * Four missions to Skylab-class space stations
|
| * One new Skylab every five years
|
| And that's not factoring in incremental improvements. Over
| time the command/service module (the "Apollo" portion) would
| have gained a glass cockpit, and even wings for controlled
| landing.
| <http://www.collectspace.com/ubb/Forum29/HTML/001337.html>
| There were similar proposals to make part of the Saturn
| rocket reusable.
| <https://forum.nasaspaceflight.com/index.php?topic=37052.0>
| But Griffin's scenario does _not_ need enormous cost
| reductions from drastic redesigns; only the inevitable ones
| that come from a steady production line optimized over
| decades.
|
| In a sense, all of this is missing the most remarkable fact:
| That this is the _head of NASA_ stating all this in writing
| in 2007, when the shuttle program had not yet ended!
| zopa wrote:
| Griffin is pulling a bit of a fast one though: comparing Apollo
| to what the Space Shuttle turned out to be, rather what the
| Shuttle was promised to become. If Congress and the country had
| known that the choice was between a continued Apollo program
| and the Shuttle we actually got, it's all too likely they would
| have chosen neither. Apollo cost too much to sustain; it's no
| defense that the shuttle turned out to cost even more.
|
| There's a lot of hindsight bias here. We know now that the
| Shuttle was a bad design that was never going to give us cheap
| and routine access to space. But I don't know that it's fair to
| expect that to have been clear at the time, before it'd been
| tried.
| j00lss wrote:
| Concurrently with Apollo, Fairchild also sold ICs to Saab in
| Sweden for the Datasaab CK-37 computer in the Saab 37 Viggen
| military aircraft. The Apollo Guidance Computer and the CK37 was
| developed more or less at the same time in the sixties. Saab used
| the TO version of the ICs while MIT used flatpacks (Block II).
|
| The ICs where called "MLEs" (Micro Logic Elements) at the time.
| From former Datasaab employee, Bengt Jiewertz [1]:
|
| "Saab was one of the biggest customers of Fairchild beside NASA
| in the beginning of the 1960s. Early component investigations and
| tests used a lot of MLE. The first 5 prototypes, delivered during
| 1962-1963, needed about 3000 MLE each. [...] We had good
| relations with Fairchild who used our experiences and made
| changes to the MLE to better fit our building of computer
| blocks."
|
| [1] https://www.datasaab.se/Papers/Articles/Viggenck37.pdf
| pomian wrote:
| Another chance to recommend a book that I learnt about from HN: I
| highly recommend the book, Sunburst and Luminary;
| http://www.sunburstandluminary.com/SLhome.html
|
| A technical pleasure and also very good glimpse into the Apollo
| team - working together, to land on the moon. It is a fun easy
| read, written by the fellow in charge of programming the guidance
| computer on the lunar lander. It is also a great snapshot of that
| time in history, the excitement of Apollo, and with the
| frustration of the Vietnam war going on, some protests, etc. Just
| a hint - the main programmer, was an English major, and his use
| of the right words, were a key factor in the success of of
| creating an efficient and effective computer language.
| Animats wrote:
| Wikipedia: "NASA's stated short-term goal for the program is
| landing the first woman and first person of color on the Moon."
|
| That's the goal?
| iamflimflam1 wrote:
| I listened to an interview with an astronaut earlier today. He
| talked about the selection process and how there's very little
| to choose between the pool of candidates as they are all
| equally incredible.
|
| So the choice can often be nothing to do with who is
| technically or physically the best as they are all the best and
| equally suitable.
|
| The choice then comes down to completely different criteria.
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