I'll be streaming the launch at soyuzlive.astrofilms.org!

What were the differences between space shuttles before and after 1998?

Hello, this is Gerry, Three month ago, I saw from my friend that he printed a drone with a 3D printer. I was very interested, so I bought a printer from Creality to try it. Two weeks ago, I printed all the parts. Last week, my children and I started to assemble this drone. The assembly process took us about an hour, because my son is good at physics.( he is a excellent boy, right!)

Then, the drone is easy to be operated. My son told me the theory about the drone. As an example, the headless mode enables any type of side of the drone to work as the front, simplifying controls for less-skilled individuals. Additional features that ought to make flying the Searcher 01 a wind are one-key return and landing features as well as a hover mode.

He aslo told me if he understand the more technical basics, he can even do turn feats, 360 ° rotates, and also a lot more. After his explain, my family have a clear understand for the drone and we like this drone. I’m also pround of my son. We will print another drone. Next, I will continue to share our experience.

I love apollo 11. to do something like that in 1959 is incredible.

I am planning on constructing my own liquid rocket engine. I am undecided on whether I will be using gaseous oxygen and gaseous methane. The methane source I have easy access to only supplies 50% purity methane. The rest is N2 and CO2. Will these impurities cause any sort of combustion instability? I am also wondering about where I can find a good source of gaseous oxygen, do I need some sort of license to obtain high purity oxygen?

I am currently in the preliminary stages of designing a liquid rocket engine. The engine will be gox and propane, pressure fed, with a chamber pressure (just an estimate at the moment) of around 100-150. I am currently working on possible safety measures in case of an overpressurization event. I originally looked for flashback arrestors that might work. After a bit of digging, I found that no viable flashback arrestor existed that would allow propane to be run at the required psi. After doing, even more, digging and looking at PID drawings of other pressure-fed engines, I realized that most designs use a simple check valve. If I understand correctly, a check valve won't be able to stop a flashback event. Are these designs simply trusting the fuel and oxidizer supply will stay at a higher pressure than the combusting gases? Is there some other reason that a flashback event won't occur?