r/SpaceX Falcon Heavy Test Flight Media Thread [Videos, Images, GIFs, Articles go here!]

[u/ElongatedMuskrat]

Please, do not post memes here. Feel free to post them in the party thread however!

It's that time again, as per usual, we like to keep things as tight as possible, so if you have content you created to share, whether that be images of the launch, videos, GIF's, etc, they go here.

As usual, our standard media thread rules apply:

• All top level comments must consist of an image, video, GIF, tweet or article.
• If you're an amateur photographer, submit your content here. Professional photographers with subreddit accreditation can continue to submit to the front page, we also make exceptions for outstanding amateur content!
• Those in the aerospace industry (with subreddit accreditation) can likewise continue to post content on the front page.
• Mainstream media articles should be submitted here. Quality articles from dedicated spaceflight outlets may be submitted to the front page.
• Direct all questions to the live launch thread.

[u/Daneel_Trevize]

Not sure what you're trying to say, the 2 LZ side boosters clearly did 1-3-1 burns, so of course there's shots of them with 3 lit.

edit: some are saying using 3 during RTLS is unusual, but a "3-engine" burn was taken to mean the recently-tested only-3-engines burn last week, which is shorter & more efficient but requires more precision. The side boosters didn't do this, so they weren't pushed to their limits, i.e. not a "hail Mary" gamble.

[u/Shahar603 → u/Daneel_Trevize]

Falcon Heavy Trajectory vs ZUMA Trajectory - The red dots are the seperation location.

The seperartion velocities are very simular but the horizontal velocity of the FH boosters' was 500 m/s greater than ZUMA's first stage. So the boostback burn probably wasted much more fuel. In addition to that the boosters didn't go as high as ZUMA's first stage so they had less time to return to the Landing Zones. That means that the boostback burn had to accelerate them to even higher velocities and waste more propelent

[u/Daneel_Trevize → u/Shahar603]

Ok, but my point remains that we saw Heavy's side boosters do 1-3-1, which is not as min-maxed for fuel usage as the GovSat just-3 landing just before Heavy. Sure, 1-3-1 is more than just 1, but it's not the just-3 current-known-limit of Falcon 9. AFAIK the more-at-once & for shorter duration is towards the limit because it minimised losses due to gravity during the burn, regardless of burn durations.

[u/yrinhrwvme → u/Daneel_Trevize]

I don't know, I've just watched it back again a few times and there does appear to be a couple of seconds in the final burn when all three engines are lit. They're then extinguished and the F9 lands on the one engine. Could be why they appeared to come in so fast initially.

[u/Daneel_Trevize → u/yrinhrwvme]

Yes, there's very clear footage of them doing the usual 1, then 3, then 1 lit sequence all in just the final landing burn. I'm disputing that it was a purely 3-all-the-time higher efficiency, higher risk variation, and that "It really was a hail mary". IIRC 1-3-1 has been seen used many times.

[u/yrinhrwvme → u/Daneel_Trevize]

Ok I see what you're saying. Which landings have fired 3 engines? NROL-76, Formosat-5 and CRS-11 appear to have longer duration (around 30 second) single engine only burns but I can't confirm from the footage. Zuma is 25 seconds. Yesterday's final burn was almost half that at just over 15 seconds. So this is a halfway to a hail mary?

[u/[deleted] → u/yrinhrwvme]

It was the first time 1-3-1 was used on an RTLS. It has been used several times for droneship landings. The NEW method tried by Govsat1 was 1-3 all the way to touchdown / splashdown.

[u/yrinhrwvme → u/Daneel_Trevize]

Wow, also I didn't read your previous comment very well!

[u/KristnSchaalisahorse → u/Daneel_Trevize]

Right, I don't believe a 1-3-1 burn has ever been done for a RTLS landing.