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1answer
407 views

How do you shut off a Merlin-like rocket engine quickly? How quickly can it be done?

After about 36:17 in part 1 of this recording of SpaceX's Hans Koenigsmann's talk at IAC 2018, he narrates the propulsive landing of a Falcon 9 first stage, and ...
0
votes
0answers
67 views

What is the mechanism principle of the grid fins in F9? [duplicate]

What is the mechanism principle of the grid fins in F9? or how to design the mechanism for the electricity grid fins? or how to design a electricity folding wing like the grid fins in F9?
3
votes
1answer
451 views

When this F9 2nd stage engine suddenly moves upon shutdown, is it moving along the rocket's axis?

The GIFs are made from frames of the live broadcast of SpaceX JCSat-16 2nd stage around the time of the second engine cut-off (SECO-2). It looks like the engine moves outward axially as the thrust ...
10
votes
1answer
999 views

If it is difficult for Merlin engine to have deeper throttling, could it be as an option a different engine at the center of the rocket?

In the landing procedure for the first stage of the Falcon 9 one concern is that : Merlin 1D throttling at its lowest level still generates more thrust than the empty mass of the first stage. So ...
5
votes
1answer
577 views

Falcon 9 engine ignition sequence

On the space shuttle, engine ignition was delayed for the main engines. Not all of them were started at once, presumably to avoid vibrations. How does that work for the Falcon 9? I imagine that the ...
6
votes
0answers
457 views

What upgrades does the Merlin 1D need to increase its time between overhauls to 1000 hours?

This is a question I've been pondering for the last few weeks after I back-calculated the details of the Merlin 1D engine. Just as a thought exercise, I wanted to see what upgrades the Merlin 1D would ...
6
votes
1answer
2k views

Does the Falcon 9 v1.1 form a shock diamond when in flight?

How does the Falcon 9 v1.1 form this exhaust pattern with its nine Merlin 1D engines? Is it a bigger, rougher shock diamond? I am trying to learn more about how one could form with a cluster of ...