HN Theater @HNTheaterMonth

You’re joking but in aerospace they use factors of not 10x or 2x but 10%. On a 30m high rocket. Just 10%. Here’s a tour with the CEO of ELA, as a bonus: https://youtu.be/OdPoVi_h0r0

SmarterEveryDay, United Launch Alliance factory visit, https://youtu.be/o0fG_lnVhHw

Earlier ULA video by SmarterEveryDay, https://youtu.be/OdPoVi_h0r0

With rockets like the Atlas 5 (flown by ULA), the rocket is assembled vertically in a tall "hanger", and is then rolled out to the launch pad, remaining in the vertical position.

The Falcon 9 is assembled rolled out to the pad horizontally, then it raised into the vertical position in preparation for launch.

It can be more complicated to design satellites (esp satellites that have large optics in them) to deal with gravity in two different orientations.

Atlas 5 "roll out": https://spaceflightnow.com/2020/07/28/photos-atlas-5-rolled-...

Falcon 9: https://www.youtube.com/watch?v=TYJuHuhPxGU

Bonus video, Smarter Every Day chatting w/ the CEO of ULA while watching a Delta IV Heavy roll out to the launch pad: https://www.youtube.com/watch?v=OdPoVi_h0r0

⬐ garmaine

How is the satellite transported to the launch site from the point of manufacture?

⬐ JshWright

Usually by truck for at least part of the journey (airplanes, boats, and trains are also commonly used). They are carried in custom built frames that hold them in the correct orientation. The frame is then surrounded by a sealed box that keeps the satellite clean, and with the appropriate climate controls (temperature, humidity, etc).

Here's a good overview of the process (though in this case it's a satellite that can safely be transported in multiple orientations): https://qz.com/1346279/big-plane/

⬐ garmaine

It just seems to me that it would need to be horizontal, and likely encounter greater stresses during transport than during a tightly controlled horizontal assembly process.

⬐ Tuna-Fish

They are not horizontal during transport.

⬐ sandworm101

Complicated and less weight-efficient. Designing a structure for gravity/g/force in one axis is wasteful enough. That strength is useless once in space. Horizontal integration means the structure must be strong in two axis: double waste. It might not matter when you are launching cubesats, but in a spy satellite the size/weight of a bus that extra reinforcement means sacrifices in many other areas.

⬐ jccooper

It's a bit more than cubesats. Nearly every satellite is or can be fine with horizontal integration. Witness every SpaceX and Russian payload ever launched.

Only exotic (presumably optical) sats from three-letter agencies really demand it, and even then we don't know if they really need it or would rather just spend the money to make it the launcher's problem rather than do a redesign or evaluation of their system.

⬐ valuearb

Today’s cheap and high cadence commercial launch systems should make the extra weight needed for horizontal assembly a non-factor.

⬐ TeMPOraL

"Cheap and high cadence commercial launch systems" are just beginning to happen right now, it'll take time for the industry practices to readjust.

⬐ valuearb

SpaceX undercut the market price for space launches by nearly 70% in 2010, and has averaged a launch every two and a half weeks for the last four years.

How much tine does the industry need to adjust?

⬐ JshWright

Lead times for large satellites are measured in years. The industry is absolutely adjusting, but it's also very risk averse.

⬐ avmich

But it's more economical, money-wise, as Russian launchers history shows. In general, American rocket school tends to have better mass efficiency but less economical efficiency that Russian rocket school.

"When he wants more thrust, Ivan doesn't look for a fancy propellant with a higher specific impulse. He just builds himself a bigger rocket. Maybe he's got something there." - J. Clark, Ignition! https://library.sciencemadness.org/library/books/ignition.pd...

⬐ dnautics

> When he wants more thrust, Ivan doesn't look for a fancy propellant with a higher specific impulse. He just builds himself a bigger rocket

On the other hand the Soviet Union did develop syntin... (also from Ignition!)

⬐ avmich

Of course the point was that one can use simple and crude solutions, or effective and sophisticated ones. Another example would be that in Russian rocket engines pumps tend to be put on the same axis as the turbine, so frequencies of turbine and pumps are the same and some of them can be non-optimal. In American tradition one uses gears, which makes both turbine and pumps (more) optimal, for the cost of gear mechanism. Practice shows that both approaches can work, but, just as with vertical assembly, which requires a tall building or a vertical transportation of a rocket, some ways look simpler than others. Simpler not necessarily better - but in rocket assembly it's probably cheaper to do it horizontally.

Tory Bruno, CEO of the United Launch Alliance, made rockets out of 80yo moldy dynamite. 6m10s

https://www.youtube.com/watch?v=OdPoVi_h0r0

⬐ zipwitch

Moldy? Psh, that's nothing. The real excitement begins when you play with the sweat coming off the dynamite, like we did back when I was a kid in the 80s!

Note: the above is sarcasm. "Sweating" or "weeping" dynamite is dangerous and you should immediately leave the area and contact your local equivalent of 'the bomb squad' to report it.

⬐ keanzu

Over time, regardless of the sorbent used, sticks of dynamite will "weep" or "sweat" nitroglycerin, which can then pool in the bottom of the box or storage area. For that reason, explosive manuals recommend the repeated turning over of boxes of dynamite in storage. Crystals will form on the outside of the sticks, causing them to be even more sensitive to shock, friction, and temperature. Therefore, while the risk of an explosion without the use of a blasting cap is minimal for fresh dynamite, old dynamite is dangerous.

https://en.wikipedia.org/wiki/Dynamite