Hope all of the engineers that struggled to get this mission spacebourne can enjoy!

1. What was testing/safety/static checking culture like? I have experience within a NASA software contractor that spent a lot of time and stress on balancing classic “aerospace-y” engineering practices with the more modern ones out of SV, which are paradoxically both more and less rigorous than the old ways across different situations. In other words: in a project like this where “groundbreaking” is expected, how closely did you stick to tradition?

2. I’m dumb and just realized: did they pick Euclid because it’s in the EU??

E: 3. What’s it like to be “accomplished”? Like, more so than any random app ceo or sales consultant or whatever, you have now accomplished what would be many young people’s dream: to help build a spacecraft that’s advancing science significantly. I’m assuming all stress dissolves and any sacrifices resolve into being definitely worth it? Asking for a friend, of course.

1. The testing culture is very thorough. I was involved on the propulsion side of things, and as such the safety is taken very seriously, for the safety of the test/production engineers and of course the spacecraft. Propulsion systems are typically integrated in such a way that it is very difficult (nigh impossible at times) to separate them if an issue is found at a later stage, so the testing goes through things with a very fine comb. And even still things can go wrong and can sometimes only be found at a later stage.

From the spacecraft Assembly Integration and Test (AIT) side of things, which is where I work, things are traditional but pragmatic. If a new way can be shown to be more reliable we will adopt it. But not before it is very well understood and characterised. In space, heritage is king, the best way to know if something will work in space is to already know it works in space. So it can take a lot of evidence for a new method/system to be adopted, and when we think we are moving quickly, it probably looks like a glacial pace to others.

During the build and test, we are often so far from the end goal of a spacecraft, its not possible to see the "groundbreaking" aspect of things. Perhaps the payload designers and engineers can see this better.

2. I believe it is named after Euclid, as the father of geometry, as the mission goal was to measure the geometry of the universe. And also yes, go Europe.

3. Christ, accomplished? I love the idea of being accomplished in many ways, but its also a scary concept. Wouldn't want to be having notions of grandeur either. I am very lucky to have worked on many great projects, in many countries, and in a job that I honestly think I am good at and enjoy. But I am always surrounded by so many people who have done so much more, so it mostly feels like I am trying to catch up really.

The science missions really are special to me, I have a background in Astrophysics, and sort of fell into spacecraft engineering. So it is always a real pleasure to get to work on something I understand on a deeper level. But most of the missions I have worked on have not been so special. Most spacecraft are to make money or do something for a military. Its why I have so much time for ESA. Even with their issues (cost, time, etc.), they really feel like they do the important missions for humanity. Nasa and Jaxa too, but they mix in a higher amount of the less special stuff in my experience.

The stress and sacrifice was stressful and sacrificial(?). I wouldnt say it was worth it, or not worth it. Its an odd one. Mostly I have just tried to do cool shit as often as I can, and I have been damn lucky.

Thanks for the kind words though, and I hope I wasn't rambling too much in my response.

But if you have seen the issues that Starliner has had recently, I would echo the statement from there, that valves are hard. Very hard. Everything to do with pressurised systems in space is hard. But the propulsion team worked it through and are now seeing the fruits of the long hours.

- Kapton P-224 - Excellent all purpose tape with good adhesion and no residue. High thermal performance and insulation

- Black Kapton 100XC - Great for increasing thermal radiative communication. Pressure Sensitive Adhesive forms a very strong bond that can be easily removed with IPA/Acetone.

- Cho-Foil - thick Aluminium tape, much stronger than the normal off the shelf aluminium tapes, commonly used for electrical grounding. Conductive adhesive, decent thermal range.

- ST150 Vacuum Sealing Tape - Used with plastic liners to create a vacuum around odd shapes. Niche, but very reliable and fun to work with (texture like taffy).

- Teflon tape - plumbers and space nerds love it for sealing things, very easy to use too much of it though.

- Glass fibre tape - excellend performance in vacuum, useful for labelling or protecting something that may be exposed to rubbing or friction.

There are a whole host of thermal tapes out there to give you lots of different optical properties that are very useful for cooling/heating: https://sheldahl.com/wp-content/uploads/2023/07/RedBook.pdf

3M VHB (Very High Bond) is awesome double-sided foam tape, that comes in a variety of thicknesses and bond types. I last used some to re-attach a piece of rubber seal around a car door.

"Gorilla Tape Crystal Clear", which I think is a "repair tape". Size of Duct tape, looks like regular clear tape - but much thicker and much stickier and waterproof. Ideal for say repairing a tear in a paddling pool. Or a crack in a roof-box, where Duct tape would look bad.

3M Super 33+ It looks like standard black vinyl insulating tape - but is a pleasure to use. I don't think the existence of insulating tape is going to blow minds, but I'm just mentioning it for those who "thought it's all the same" and are "annoyed by it".

Self-Amalgamating Tape. Black, thick, rubbery tape with a pull off backing. Not very sticky, so doesn't immediately feel useful. What it does do though, is bond with itself. Not 'stick', but as the name says 'amalgamates'. If you've ever wrapped a load of tape around something to keep water out, this is what you should have used.

I wouldn't normally inflict this list on anybody, but 'tape' is this wonderful area of technology where everybody knows what it is - but there's seemingly endless specialization for every conceivable use case. Finding/collecting these tapes feels like I'm assembling a box of solutions - and a tape-suitable problem is an opportunity for happiness.

We work for a lot of launcher companies, but ABL is the most interesting for me (even though we do relatively little for them). The containerised approach to the entire system is a really clever adaptation of existing methods to create a rapid launch system.

I annecdotally find that i remember things much more clearly when I write with them, particularly when I use varying ink colours. And when I flick back through notes seeing the colour for a topic makes it much easier to skim and recall knowledge.

To add to tge recommendation list, the Muji fountain pen is perhaps the most enjoyable pen I have, including all of my (embarrassingly) expensive pens.

Many a lot don't appreciate the power of hand-writing with a simple pen on a paper; it is a super power.

And yes, love the Muji too. I bought a few, just in case. I think, I'm starting to collect.

However, as a pictoral reference the newer documents arent as clear for me, so this online database is still very useful.