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
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.
>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.
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.
Challenger was inevitable. The risks were known and there was an estimated loss of two missions.
I remember this being reported in New Scientist in the early 80s.
The Shuttle was - unfortunately - neither well-engineered nor well-managed.
I had a friend who worked on one of the early design iterations of the ISS. When I joked I'd get her a shuttle flight for her birthday she said "You'd never get me up in that thing. I've seen the plans."
Whether Apollo could have continued with no missions lost is an open question.
> 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/1986/03/05/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!
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.
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."
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.
Thanks for sharing this. I had the pleasure to work with Don Eyles in a previous job, he is a brilliant man, didn’t realize he had written a book. I actually didn’t even realize who he was initially when I first met him until another co-worker told me of Eyles’ history.
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.
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.
One approach is to use powerful and cost efficient COTS hardware for generating the outputs, and then you can have a much simpler rad hard computer take those in to generate the final decision. You also need all kinds of watchdogs to make sure you can reboot if something shits the bed, and you have to be careful about how things communicate to make sure that one faulty computer won't spam the others into uselessness
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.
> With Artemis missions, NASA will land the first woman and first person of color on the Moon, using innovative technologies to explore more of the lunar surface than ever before. We will collaborate with commercial and international partners and establish the first long-term presence on the Moon. Then, we will use what we learn on and around the Moon to take the next giant leap: sending the first astronauts to Mars.
There's a lot of redundancy they talk about in the computing; how does that reconcile to a single output eg. where it funnels down to a discrete actuator?
And are the decisioning systems (eg. which track/decide which of the four computers to trust) and actuator itself (and surface/component it controls) engineered to a higher standard to mitigate the reduced redundancy available at the "edge" of the system?
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.
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.
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.
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.
Readit News
https://youtu.be/OoJsPvmFixU?si=dHI-_EbDzcqJc-vF
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.
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
Deleted Comment
>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.
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
I remember this being reported in New Scientist in the early 80s.
The Shuttle was - unfortunately - neither well-engineered nor well-managed.
I had a friend who worked on one of the early design iterations of the ISS. When I joked I'd get her a shuttle flight for her birthday she said "You'd never get me up in that thing. I've seen the plans."
Whether Apollo could have continued with no missions lost is an open question.
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/1986/03/05/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!
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.
Deleted Comment
Dead Comment
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
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.
Failure of that I imagine would be catastrophic.
[1] https://en.wikipedia.org/wiki/Triple_modular_redundancy
[2] https://en.wikipedia.org/wiki/Byzantine_fault
That's the goal?
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.
> With Artemis missions, NASA will land the first woman and first person of color on the Moon, using innovative technologies to explore more of the lunar surface than ever before. We will collaborate with commercial and international partners and establish the first long-term presence on the Moon. Then, we will use what we learn on and around the Moon to take the next giant leap: sending the first astronauts to Mars.
https://www.nasa.gov/specials/artemis/
I hope you'd agree that's a bit more exciting than "we want to go back to the moon again."
What's the goal of your comment?
And are the decisioning systems (eg. which track/decide which of the four computers to trust) and actuator itself (and surface/component it controls) engineered to a higher standard to mitigate the reduced redundancy available at the "edge" of the system?
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.
* 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.
That's all non-computer stuff.