Major US Launches this Week: ★ WED CA Falcon9 / SDA Tranche ★ THU FL Falcon9 / Indonesian Comsat • SAT CA Falcon9 / Starlink ______ Updated: 13 SEP / 1410 (all times US Eastern) Last week
Stuff That’s Hard to Do (31 AUG – 6 SEP)
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 ______ 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.
Stuff That’s Hard to Do (24-30 AUG)
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
Amazing view of Starship landing burn and splashdown on Flight 10 pic.twitter.com/hcr2zqOi9G
— Dima Zeniuk (@DimaZeniuk) August 28, 2025
Stuff That’s Hard to Do (17-23 AUG)
Major US Launches this Week: • MON CA Falcon9 / Starlink 100th mission of the year ★ THU FL Falcon9 / USSF X-37B Space Plane (RTLS) • FRI CA Falcon9 / Starlink (nice vid) - SAT NZ Electron ______ Updated: 23 AUG / 1840 (all times US Eastern) Last week Rocket PrOn: ● SUN 24th 7:30 pm TX Starship
The tenth flight test of Starship is preparing to launch as soon as Sunday, August 24 → https://t.co/UIwbeGoo2B pic.twitter.com/j0YKKgAxAV
— SpaceX (@SpaceX) August 15, 2025
Stuff That’s Hard to Do (10-16 AUG)
Major US Launches this Week: ★ MON FL Falcon9 / Kuiper - TUE FL Vulcan / USSF • THU CA Falcon9 / Starlink • THU FL Falcon9 / Starlink ______ Updated: 15 AUG / 1600 (all times US Eastern) Last week
Stuff That’s Hard to Do (3-9 AUG)
Major US Launches this Week: • MON FL Falcon9 / Starlink - MON NZ Electron/ iQPS (nice staging and fairing sep vids) ▶︎ FRI ISS Crew Dragon / separation from ISS ▶︎ SAT CA Crew Dragon / Recovery
For info, click on X and Grok it.
Don’t miss the nifty shutdown transients in full-screen.
Archimedes full mission duration hot fire. Enjoy. pic.twitter.com/jF3I3zDM9G
— Rocket Lab (@RocketLab) August 7, 2025
Next week, Mach diamonds
Engineering Fun:
MaxQ is maximum aerodynamic pressure.
Think of aerodynamic pressure, Q, as felt wind.
Q = 1/2 x (air density) x (speed squared), so it goes from zero at liftoff to zero in space.
MaxQ is one of the primary design points, like liftoff and stage separation, that drives structure, dynamics, and control.
Basically, if it’s gonna break-up, it’ll be by here.
Where maxQ is the big driver, it requires structural strength and control oomph, i.e. it costs mass, dollars, and payload.
Avoiding the worst of it allows you to trade-off performance, cost, and reliability.
Therefore, they throttle-down around maxQ to avoid needing all that mass while staying within structural and control margin requirements.
Again, a slide rule is required beyond this.