Fun & Curios

Stuff That’s Hard to Do (31 AUG – 6 SEP)

DougM 
Major US Launches this Week:

• SUN FL Falcon9 / Starlink
• TUE CA Falcon9 / Starlink
• WED FL Falcon9 / Starlink
• FRI FL Falcon9 / Starlink (500th launch/landing of an orbital-class rocket)
• SAT CA Falcon9 / Starlink
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Updated: 6 SEP / 1430 (all times US Eastern)
Last week

Engineering Fun:

Entry Burn.
Why not just do a landing burn only?
Because aft-end aerodynamic heating is an engineering nightmare.
Heating and Drag ~ (air density)x(speed squared) for a given orientation (attitude).

In the upper atmosphere, air density ≈ 0, so heating and drag are small.
Upon entering the middle/lower atmosphere, density becomes more and more significant.
Also, speed has been increasing due to gravity free-fall after reaching ballistic apex.

The entry burn quickly slows the booster’s falling speed before aero heating becomes damaging.
The booster then slows aerodynamically as air density increases and drag > weight.

It’s fun to replay the vid around entry burn and watch the speed numbers.
Sometimes, you can see the speed increase for a few seconds after entry-burn shutdown,
until air density increases enough for drag to start slowing the fall.

Yeah, pretty sure that’s how it works, without a slide rule and tables of data.

Fun & Curios

Stuff That’s Hard to Do (24-30 AUG)

DougM 
Major US Launches this Week:

▶︎ SUN FL Falcon9 / Cargo Dragon (Docking)
★ TUE CA Falcon9 / NAOS (nice vids, RTLS*)  
● TUE TX Starship (Spectacular!) Commentary
• WED FL Falcon9 / Starlink 
• THU FL Falcon9 / Starlink (first 30-mission booster)
- FRI NL** Nordspace /initial suborbital test flight (failure to ignite) 
• SAT CA Falcon9 / Starlink  
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Updated: 30 AUG / 0100 (all times US Eastern)
Last week
* Return to Launch Site (landing at the old SLC-4W site)
** Newfoundland, Canada

Rocket PrOn:
(view full-screen)