The Engineering Design Process ... With My 5 Year Old Daughter (Pt. One)

When my 5 year old daughter informed me last winter that she wanted to build a rocket I was over the moon (pun intended)! We had just watched the moon landing of "Odysseus" built by Intuitive Machines and had previously watched several SpaceX launches all the way back to Crew-2 in 2021, so it would be an understatement to say I have been waiting for this moment!

But how can I make it about more than just the rocket? How can I keep her engaged and interested? Well ... I figured maybe we just try to walk through the entire engineering design process together. Why not build our rocket the same way companies and nations build theirs? Why not go through the entire engineering design process and plan every step of the way?

Over the next few blog posts, I will be chronicling our efforts to build a rocket together! This is mainly for her future self to look back on and enjoy but we are sharing in hopes that it will inspire others to do the same. We will use the following, slightly simplified version of the design process throughout our build.

Step One: Define the Problem

In its truest sense, we aren't trying to solve a problem with our rocket, we are just building to learn and have fun. However we did talk about why companies and governments build rockets and why there are different types of rockets. For example, a critical part of the Space Shuttle design was that it could carry BOTH a large number of astronauts (7) and a very large payload! This requirement was very important to building the International Space Station! So what about our rocket?

Step Two: Research and Requirements

As with any engineering project, defining the requirements is a critical step. I have seen even great engineering teams completely fail in the face of uncertain requirements or product direction. For our rocket, there are a lot of possibilities but we condensed it down to the following question I asked my daughter. What do you want your rocket to do?

We had a requirements discussion at dinner one night and after we discussed the rocket for about 10 minutes my five year old came up with some requirements. As part of this process, we talked through some constraints and reached some compromises. The first requirement was, of course, she wanted her rocket to take an astronaut to space. However, after a brief discussion about the realities in that, she decided we could scale back that requirement for our backyard tests. And that led to our first requirement that the rocket should fly really high ... higher than the trees!

The next set of requirements she came up with are pretty fascinating but they make complete sense. After we discussed making the rocket fly really high, she almost immediately said she wanted the rocket to land. I laughed a bit at that because I realized she doesn't even know a world where rockets didn't land. The first fully crewed SpaceX mission Crew-2 was in 2021 and she was only two years old at the time we watched that mission. From her perspective, it's completely obvious that the rocket should land and be reusable, because that is just how rockets work. Getting tiny glimpses like this of the world through her eyes is such an incredible gift for me :)

In any case, while we were discussing the rocket "landing" she also said right away she wanted it to float. There is a small pond "downrange" from our launch site in the back yard and she wanted to be sure we could still retrieve the rocket if it landed in the pond! I was proud she thought of this requirement without any prompting! This led to us walking outside on the deck and looking at the pond. It's too large to reach across, even with a long stick or pole, so I asked her how we would get the rocket if it landed in the pond? She settled on "using the kayak" as a good starting solution. I already can't wait for the next version of our rocket to have a remote controlled retrieval drone-ship!

Finally we chatted about our "astronaut". I absolutely loved that she wanted the rocket to carry an astronaut because it led us to talk about safety and how critical it was for rockets to be safe for astronauts (more on engineering quality and resiliency later). I suggested we start with an egg ... and make sure we can launch and land safely without breaking the egg before we use any other astronaut (like one of her stuffies). She was quite happy with that idea so we wrote it down! And there we had it. We've identified a problem and some basic requirements to think about. We are going to build a rocket that

1. Flies really high and carries an egg (a stuffy in the future)

2. Is going to land and be reusable

2a. The rocket must float / be waterproof in case it lands in the pond

3. Is going to keep the egg from breaking at any point

Now its off to some strategic design! I will post another update as a separate blog post once we have some designs!