50th anniversary of Apollo 11

I recall watching on live TV in 1969 Neil Armstrong stepping onto the Moon for the first time. I still think the Apollo programme is mankind’s greatest technological achievement to date, especially taking into account the state of the art in the 1960s, albeit massive funding, around 400,000 professionals and some 5,000 companies working on the project helped immensely.

If you have a technical background and are interested in learning a bit about the technical aspects of the equipment and the mission, I can recommend W. David Woods’ book ‘How Apollo Flew to the Moon’. I found the sections on guidance particularly interesting. The book even addresses eating, ablution, urinating, defecating and waste disposal on the journey.

On the 40th anniversary of Apollo 11 I wrote a short post in the Sabayon Linux forums on using Audacity to analyse the recording of Neil Armstrong’s famous “One small step”, which I refreshed in this blog for the 42nd anniversary (see One small step for [a] man… revisited using Audacity).

To mark the 50th anniversary of the launch of Apollo 11, on 16 July this year I went to the cinema to watch the Todd Douglas Millar’s documentary ‘Apollo 11’ (see Apollo 11 [Official Trailer]), which has received good reviews due to its use of 65mm and 70mm footage. Actually, although I very much enjoyed it, quite a lot of the footage used is not 65mm or 70mm, and I found the soundtrack too loud, often making it difficult for me to make out what the controllers and astronauts said. Anyway, if you have not been to see it, I can still recommend it.

This week the UK TV channel BBC Four showed the US PBS (Public Broadcasting Service) excellent multi-part documentary ‘Chasing the Moon‘, which I found riveting. In fact, I much preferred it to Todd Douglas Millar’s ‘Apollo 11’, although the two documentaries are different animals and not really directly comparable. Anyway, if you are interested in the US-USSR space race, the internal politics behind the Apollo programme, and the Mercury, Gemini and Apollo programmes, I can thoroughly recommend ‘Chasing the Moon’, which is to be released shortly on DVD if you do not have the chance to catch it on TV or to stream it. I found the comments by Sergei Krushchev (the son of Nikita Khrushchev) particularly interesting, especially his mention about the hushed-up death of a Soviet cosmonaut in a fire during a test with a pure-oxygen environment prior to the Apollo 1 accident. If the Americans had known about this, it might have prevented the equally gruesome deaths of Grissom, White, and Chaffee in 1967.

YouTube is a gold mine if you are interested in old and newer films, documentaries and vlogs on the Apollo programme. There are hundreds of videos about it. If you are a computer buff, the videos on the AGC (Apollo Guidance Computer) are fascinating. The recent series of videos on the restoration to working condition of a privately-owned scrapped AGC are fascinating. Below are a few of the documentaries and videos I have watched this week to celebrate the 50th anniversary of Apollo 11. I have included links to a couple of the videos in the above-mentioned series on restoration of an AGC; you will be able to find the others in the series if you are interested.

  1. Chasing the Moon
  2. Spacecraft Films The Mighty Saturns Part I The Early Saturns
  3. Spacecraft Films The Mighty Saturns Part II The Saturn V
  4. Moon Machines: Command Module (2/6)
  5. Moon Machines: Navigation Computer (3/6)
  6. Moon Machines: Lunar Module (4/6)
  7. MIT Science Reporter – Computer for Apollo (1965)
  8. MIT Science Reporter – Landing on the Moon (1966)
  9. MIT Science Reporter – Returning from the Moon (1966)
  10. MIT Science Reporter – Food For Space Travelers (1966)
  11. The Real Story Behind the Apollo 11 Computer Error | WSJ
  12. The Journeys of Apollo
  13. The Apollo 4 Mission (1967)
  14. The Flight Of Apollo 7 (1968)
  15. Apollo 8 – Go For TLI (1969)
  16. Apollo 10 – To Sort Out The Unknowns (1969)
  17. Apollo 11 Saturn V Launch Camera E-8
  18. Restored Apollo 11 Moonwalk – Original NASA EVA Mission Video – Walking on the Moon
  19. Moon in Google Earth – Apollo 11 Landing
  20. Hear Buzz Aldrin tell the story of the first moon landing
  21. NASA: Moon Landing – Apollo 11 Descent Film and LRO [Lunar Reconnaissance Orbiter] Imagery
  22. Apollo 11: The Complete Descent
  23. Why were there missing rungs on the Lunar Lander’s Ladder?
  24. Apollo AGC Part 1: Restoring the computer that put man on the Moon
  25. Apollo AGC Part 23: Flying realistic Apollo 11 moon landings with the Apollo Guidance Computer
  26. An Audience with Neil Armstrong (2011 interview)
  27. Apollo 11 crew member [Buzz Aldrin]
  28. WATCH: Astronaut Michael Collins discusses the Apollo 11 launch 50 years later
  29. Apollo’s Most Important Discovery (Inside NASA’s Moon Rock Vault!)
  30. Where does NASA keep the Moon Rocks? – Smarter Every Day 220
  31. APOLLO MOON SUIT: demonstration of functioning, and manufacturing (1969)
  32. Moon Machines: Space Suit (5/6)
  33. The Space Suit Special

Conspiracy theories and their debunking

  1. NASA: Moon Landing – Apollo 11 Descent Film and LRO [Lunar Reconnaissance Orbiter] Imagery
  2. Moon-Landing Hoax Still Lives On, 50 Years After Apollo 11. But Why?
  3. Apollo and the moon-landing hoax
  4. Moon landing conspiracy theories – Hoax claims and rebuttals
  5. A Brief History of Moon Hoaxes – Why do people still believe in them?
  6. Why Faking the Moon Landing Was Impossible
  7. Debunking the Myth that the Moon Landing Was a Hoax
  8. Nvidia Debunks Conspiracy Theories About Moon Landing
  9. Moon Hoax: Debunked!
  10. The Space Suit Special


And, finally, these videos about the USSR’s failed attempt to put a man on the Moon are worth watching:

  1. Why Russia Did Not Put a Man on the Moon – The Secret Soviet Moon Rocket
  2. Soviet N1 Moon Rocket Documentary

Amazing that the NK-33 closed-cycle engines originally developed for the N1 were purchased by a US company, modified and finally used in a new launcher in 2013. The later and larger RD-180, also a Russian closed-cycle engine, is – if I understand correctly – still used to power US Atlas rockets until US-designed replacements are available.

Why I switched from WhatsApp to Signal

I had avoided WhatsApp until late 2017 when one of my family installed it on my phone with the promise I would find it useful to keep in touch during a two-month work trip. Actually, it turned out to be more useful for work, as WhatsApp is the preferred method of communication at the company I visited on that trip.

Now, I was aware that Facebook acquired WhatsApp in 2014 for US$19 billion. I do not have a Facebook account and have no intention of getting one, and the fact Facebook owns WhatsApp was one of the reasons I had been reluctant to install WhatsApp in the first place. However, it didn’t take me long to like WhatsApp. The UI is very well designed, the functionality excellent and WhatsApp Web is easy and convenient to use. WhatsApp is a polished product, no doubt about that. The end-to-end encryption of WhatsApp messages is comforting, although that was not my main reason for using it. Offhand I can only think of one function I find annoying in the WhatsApp UI: when you forward a message containing an image, there is no automatic way to include the text accompanying the original message.

Recently I have read several articles stating that Facebook intends to display advertising in WhatsApp from 2020 onwards. I am sick and tired of ‘surveillance capitalism‘ tracking me and bombarding me with advertising on the Web, and this news prompted me to search for a replacement for WhatsApp. A newspaper article mentioned Signal, which I learned happens to be the source of the encryption protocol used by WhatsApp. I also learned that WhatsApp co-founder Brian Acton, who left Facebook in 2017, is Executive Chairman of the Signal Foundation, which he co-founded with the creator of Signal in 2018. So I decided to give Signal a try, and was pleasantly surprised as the UI is very similar to WhatsApp. OK, it’s not quite as polished aesthetically, but it was easy to use from the get-go.

I initially found Signal’s security-related functionality confusing. I was not sure what the so-called ‘Safety Number‘ per contact does. It turns out that you can ensure your connection with a given contact is secure by ‘verifying the Safety Number’ with that contact. From then onwards ‘Verified‘ will appear next to the contact’s name and phone number at the top of the conversation window. Verifying the Safety Number is optional, which was not clear to me initially. Each contact’s Safety Number is actually a 3 x 4 table of 5-digit numbers. You should compare the Safety Number in your app with the Safety Number in your contact’s app in a way that prevents someone intercepting you both; you can either scan a QR Code or make a visual or audible comparison of the Safety Number in your app with the Safety Number in your contact’s app. If both Safety Number tables match, you can both click on ‘Mark as verified’ in your app. The app will then warn you if a safety number has been changed because someone is intercepting your conversation (a so-called ‘man-in-the-middle’ attack).

The other security-related function I found confusing initially is resetting a session (‘Settings’ > ‘Reset session’). It is normally not necessary for you to touch this, but, if for some reason the encryption keys between two contacts no longer match (the Signal app would notify you if that occurs), either party can reset their session and force Signal to negotiate a new session.

Unlike WhatsApp, Signal does not have a Web browser UI to use on desktop machines. It used to have such an interface (using Google’s Chrome browser) but now there is a Signal desktop app instead, with versions available for Windows, Mac OS and Linux. I have Gentoo Linux on my laptops and Lubuntu Linux on the family desktop, so I have installed the Linux desktop Signal app on those machines.

Unlike WhatsApp, the phone app and the desktop app do not sync earlier messages. By this I mean that, if you install the desktop app and launch it, you will not see any earlier messages that are visible in the phone app. Similarly, if you delete a message in the phone app it will not be deleted in the desktop app, and vice versa. This is a bit of a nuisance, but is OK once you get used to it. Perhaps this has been done with security as well as storage capacity in mind; Signal stores as little of your data as possible on its servers.

Below are a few aspects of Signal functionality that I prefer over WhatsApp:

  • In the phone app it is possible to set the colour of the background (‘wallpaper’) for contacts, not just the top-level page. Thus I have made the background black for contacts to help a little to conserve the phone’s battery charge.
  • When I forward a message that includes an image, Signal includes the original text as well as the image. Further more, it gives me the opportunity to edit the message text before actually forwarding the message.
  • When I forward a message containing an image, the whole image is displayed. For example, recently someone sent me a WhatsApp message containing a cartoon which I did not understand; I did not realise there was a caption until I tapped on the image to expand it. When I forwarded the message to a Signal contact (by selecting the message in WhatsApp and tapping the Share icon), the caption at the bottom of the cartoon was visible in the resulting Signal message without needing to tap on the image.
  • The Signal phone app lets you disable link previews (a.k.a. ‘URL previews’) easily in Settings, whereas you cannot disable link previews in WhatsApp (see Should WhatsApp let you disable URL previews?).
  • Signal allows you to specify a message lifetime (‘Disappearing messages’). You can specify that messages will never be deleted automatically, or will be deleted after a certain time has elapsed (user-selectable from 5 seconds up to 1 week).
  • Although WhatsApp uses Signal’s encryption technology, unlike Signal it does not encrypt backups.
  • Unlike WhatsApp, Signal does not store message metadata.
  • Signal is fully open-source (and free of charge, with a promise of no advertising). WhatsApp is closed-source.
  • The icons of contacts are obtained from your phone’s contact list, not specified within the app itself. Some of my WhatsApp contacts have not bothered to create an icon in WhatsApp, but I had set up an icon for them in my phone’s contact list, and that icon is used in Signal.

Below are a few aspects of WhatsApp functionality that I prefer over Signal:

  • Signal has the ability to show link previews for a few Web sites (currently for Imgur, Instagram, Reddit, and YouTube only), whereas WhatsApp shows them for all sites. (From a security perspective some people might regard this as a disadvantage of WhatsApp.)
  • I prefer the white/green ticks in WhatsApp to the unfilled/filled circles with ticks in Signal, but that is purely an aesthetic opinion.
  • WhatsApp syncs all messages between the phone app and the Web UI, not just new messages, whereas Signal just syncs the messages sent and received since you installed the desktop app. (From a Security perspective some people might regard this as an advantage of Signal over WhatsApp.)


In general I find Signal as good as WhatsApp, if not better. I had been worried I would not find an alternative to WhatsApp that is as easy to use and as intuitive. In fact Signal is very good, and, once you understand the security features I mentioned above, it is essentially the same as WhatsApp, which was a relief to me as I like the general concept of the WhatsApp UI.

At the moment I am having to use both WhatsApp and Signal because some of my contacts only use WhatsApp, but I have already persuaded some contacts to switch to Signal and I anticipate more will migrate to Signal once WhatsApp begins displaying adverts next year.