sevenperforce

The orbital track shows the prior path overlay, so you can see where it went from LEO to GTO. Also, stars in the animation. Block 5 webcast?

The color balance on the new cameras is totally different. The Mvac looks way badass in the darkness.

That could be a good thing or a bad thing.

Yeah, it seemed super loose. Odd.

Not just you. Its thrust went up dramatically. 108% is nothing to sneeze at.

There's always a temporary S2 LOS when it passes between ground stations.

Noticeably less fire around the base than I remember.

Congrats to SpaceX, and welcome home Block 5.

Way off-center. But damn, what a sight.

SECO happens before landing burn rather than simultaneously as in the past. TOUCHDOWN!

There is a white circular piece inside the interstage...presumably to shield it from the MVac engine plume. Brand new cameras on S1. They wobble more. Entry burn!

Block 5's MECO for ASDS flights happens at 2:30....which happens to be the time when Block 4 had MECO on RTLS flights.

AND THAT IS WHAT A BLOCK 5 MVAC LOOKS LIKE They made a bunch of space for a party ballooooooon. There goes the fairing!!!

Max-Q passed. Man, it is pitching over hella fast. That engine uprating is ridiculous. The view inside the interstage looks completely different now.

THOSE LEGS THO Reminds me of a Saturn V launch with those stark contrasts.

LIFTOFF!!!! (kidding, kidding)

BFS is infinitely restartable so there's no reason it can't simply inject to a circular parking orbit and then catch up when it needs to. Inclination is always an issue, but....

Let's see. Assuming a nominal 5-tonne payload, S1 burns 2.75 m/s to get to staging. About three fifths of that goes to fighting gravity drag and aerodynamic drag. If we guesstimate the first stage to have a staging mass of 105 tonnes for an ASDS mission based on 20% propellant reserves for EDL (I may be overestimating this), then we will need around 240 tonnes of props to get back home from the ASDS, including the entry and landing reserves. That's about 60% of a full prop load. Landing legs for Block 5 can be refolded but you'd need a launch pad of some kind with hold-downs since the legs obviously cannot be refolded mid-flight.

Well, more margin is always better. Obviously they are not going to burn further downrange than they have fuel to boostback from. Also, you don't have to scrub off prograde velocity; you only have to scrub off downrange velocity. Gravity is your friend. Let's take a look at CRS-12 in the above graphic. A triangle with the hypotenuse tangent to the velocity vector at staging has a horizontal component that is 78% of its magnitude (thanks, Pythagoras). A quick glance at the CRS-12 webcast on YouTube tells me that staging velocity was 1.66 km/s. So scrubbing out horizontal velocity will cost the naked first stage 1.29 km/s. At zero horizontal velocity, the stage is now 96.5 km downrange and at an altitude of 104 km. Using basic kinematic equations, the stage would need 663 m/s to get back to land, assuming a ballistic trajectory. However, vertical velocity is not zero, so your extra hang time means you only need 338 m/s to get on a trajectory which hits the landing pad. Now, the "dense" atmosphere begins at 30 km, when the CRS-12 booster was only 6 km downrange and speeding back. However, with titanium grid fins, the booster can hit the denser portion of the atmosphere 30 km downrange, because its L/D ratio can take it the rest of the way. So instead of 338 m/s, the "return" segment of the boostback burn only needs to provide 233 m/s. So CRS-12 had a boostback of about 1,628 m/s, but if it had been equipped with titanium grid fins, it would have needed a boostback of about 1,523 m/s. At least some of that extra ~105 m/s could have gone to the upper stage before separation, giving just a slightly larger kick to the upper stage. I don't think that was ever on the table. That was on the digital menu they were considering but never actually got around to printing out. The logistical challenge of refueling at sea and flying the stage back to land is......unbelievably immense. This is probably not too challenging.

I only do orbital rockets I have concrete specs and payloads for. =P

Surprising.............no one. IN BREAKING NEWS, SPACEX SELECTS MERLIN 1D FOR BLOCK 5 FALCON 9 INDUSTRY TITANS SHOCKED TO LEARN NEW GLENN ROCKET WILL FEATURE BE-4 ENGINE TWITTER ABUZZ AS TRUMP SHOCKS COUNTRY BY SELECTING REPUBLICAN FOR NEW CABINET POSITION EXTRA! EXTRA! WATER NOW WET

First of all, we know that Elon said the new grid fins give it a high body lift glide ratio, which allows S1 to deliver more energy to S2. Second, the four RTLS missions on the graphic you sent were with Al grid fins, so of course it had to come in nearly vertical, because there was no glide ratio. Plus, these had lower velocities at staging, and weren't as far downrange, as a Block 5 booster will be. Here's a graphic showing how a Block 5 RTLS might look: As you can see, staging is farther downrange due to B5's higher thrust. The green line shows the required trajectory if the boostback burn did all the work; the red line shows the effect of using glide ratio.

When is the Antares static fire? Kidding, kidding. Let's see...this will be my very first Cygnus mission.

The graphic is completely not to scale. The stage is quite far downrange on even high-margin RTLS missions. Here's Elon talking about using the grid fins to fly back: Since the audio is bad, here's a transcript: In the Zuma mission, the booster was 60 km high and doing 1.7 km/s downrange at staging. If it burned off that 1.7 km/s, it would fall straight down into the ocean. To get back to its origin point, it would need to burn an additional 1.7 km/s, if you look at patched conics. But with the new grid fins, it may only need to do a 1 km/s kick back toward the shore, and let the glide ratio carry it the rest of the way to the pad. Heh. In all seriousness, the idea is non-destructive testing and component stress. Those nine engines take a beating during launch and landing; the easiest way to verify that they will start up and function normally is to fire them up for a few seconds.

I suppose that high-margin, low-performance missions could do a 5-second hold down at launch and have the computer automatically give a go-no-go. Though I'm sure static fire data review has been lengthy up to this point.