RocketLab Discussion Thread

[Nightside]

1 hour ago, Listy said:

I wonder how far south the typical catch zone will be for a sun synchronous launch? If there's no boost back involved then somewhere in the southern ocean roughly between Wellington & Christchurch? Mahia peninsula is already on the fringe of the roaring 40's, and a number of Rocketlab launches have experienced weather delays so far. The chopper pilots will be earning their pay trying to catch a spent rocket in a 50 knot westerly.

I was thinking the same.

[magnemoe]

12 hours ago, cubinator said:

They will need to turn the rocket around anyway; in the animation it looked like they won't do any extra burns but it will have to enter tail first while still moving prograde. My guess is they would use a cold gas thruster system to point it in the right orientation, then basically not have to do anything after that.

Also, IIRC small things get slowed down faster by atmosphere, so heating may be much less of a concern than for F9.

Cold gas trusters should work. once engines are first it should be stable enough, they can add some drag features if needed 

Dry mass is just one ton so it should slow down pretty fast and is something helicopters would have few issues with. 

Heating, they might want to put an skirt around the engines and protect some sensible part there else the plan looks feasible enough. 

[CatastrophicFailure]

5 hours ago, magnemoe said:

Cold gas trusters should work. once engines are first it should be stable enough, they can add some drag features if needed 

Tiny. Little. Gridfins. 

Maybe even actual waffle irons. It is just for testing, after all...

[Wjolcz]

In the video there were some sort of grey elements on the interstage. I wouldn't be surprised if those were some sort of aerobrakes.

[ThatGuyWithALongUsername]

I'm just wondering how they're gonna protect the engines.

[Wjolcz]

1 minute ago, ThatGuyWithALongUsername said:

I'm just wondering how they're gonna protect the engines.

Entry burn just before the worst part of the flight?

[magnemoe]

32 minutes ago, CatastrophicFailure said:

Tiny. Little. Gridfins. 

Maybe even actual waffle irons. It is just for testing, after all...

Yes however they don't need control just moving their center of drag backward. 
Make the drag parachute kind of an balute, it looked kind of inflated at the start, it you pressurized with an low pressure it would inflate in upper atmosphere but collapse then they get down but then you pop the main parachute. 

Skirt around the engines or at least the upper parts will protect the sensible parts from most of the airflow. Now you only need to protect an stupid ring rather than lots of wiring and stuff 

[tater]

 

And the stuff about photon from last month:

 

~2.9 km/s to bleed off, not propulsively.

They've been gathering data on S1 entry since the last few flights.

Rationale is launch frequency as primary goal, secondary might be lowering prices. He says that even if they only get one reuse, they effectively double their manufacturing capacity.

[tater]

He doesn't mention it, but the interstage clearly looks like it has integral fins that perhaps pop open upon staging (it's 100% passive, otherwise, so it needs some aero forces to flip it tail first I'd think).

[Geonovast]

Could they put something inside the interstage, some sort of fin or ramp, that would cause it to flip from the exhaust of the second stage?

[Wjolcz]

12 minutes ago, Geonovast said:

Could they put something inside the interstage, some sort of fin or ramp, that would cause it to flip from the exhaust of the second stage?

The problem with this is if they did that the stage would start tumbling. I'd think that causes more problems than solves. The best way to make sure that the stage reenters properly is to make a shuttlecock out of it ASAP after stage separation.

Edited August 7, 2019 by Wjolcz

[Geonovast]

1 minute ago, Wjolcz said:

The problem with this is if they did that the stage would star tumbling. I'd think that causes more problems than solves.

That would depend on how much of a push it got.  I'm talking very, very little.  Just enough so that it's engine-first when it hits the relevant part of the atmosphere. ¯\_(ツ)_/¯

[Wjolcz]

1 minute ago, Geonovast said:

That would depend on how much of a push it got.  I'm talking very, very little.  Just enough so that it's engine-first when it hits the relevant part of the atmosphere. ¯\_(ツ)_/¯

That would take some serious precision and measurements. Besides, I'm sure it orients itself engines-first during reentry without that.

[ThatGuyWithALongUsername]

They might not need anything at all to keep it pointing down. With all the batteries and such at the bottom of the rocket, it might be able to flip itself and remain stable.

Edited August 7, 2019 by ThatGuyWithALongUsername

[cubinator]

They plan to use lots of TPS to deal with the heating, according to the presentation.

[CatastrophicFailure]

1 hour ago, tater said:

He doesn't mention it, but the interstage clearly looks like it has integral fins that perhaps pop open upon staging (it's 100% passive, otherwise, so it needs some aero forces to flip it tail first I'd think).

Having some amount of control is a good thing, especially if you want to get it within range of a waiting helicopter. And like SpaceX has demonstrated, enough control to cock the booster just a little sideways so it “glides” creates more drag, so it slows down quicker and higher, potentially reducing heating. 

[Silavite]

Interview with Beck by Ars Technica

I will say that I found this statement interesting⁠—

Quote

⁠Ars Technica: Business must be pretty good if you need all these Electrons.

Peter Beck: We've brought something to the market that was sorely needed, and we think we've hit the sweet spot for payloads. It's enough that you can rideshare a few CubeSats, but it's really spectacularly ideal for a dedicated smallsat launch. A 150kg or 200kg spacecraft—the Electron really suits it well. Launch has always been constrained, but we're helping to ease the problem.

This statement seems to suggest that there could be enough demand for a similarly sized LV for another company to be successful—even after the inevitable industry shakedown.

 

And on the subject of a shakedown...

Quote

Peter Beck: I lost count, personally, at 114 small-launch vehicle companies. I was told this morning that it was announced at this conference that there are now 130.

I couldn't have imagined having 130 small-launch vehicle companies existing a decade ago. It's amazing how times change.

Edited August 8, 2019 by Silavite

[tater]

49 minutes ago, Silavite said:

I couldn't have imagined having 130 small-launch vehicle companies existing a decade ago. It's amazing how times change.

That said, there is probably only room for a handful to survive worldwide (and only 2-3 for the US market, IMO).

[Guest]

@_@!

Wow, good for them! I wonder what the costs will be like after! 

(They are fast becoming my second fave space company :3)

*oh I see you guys are already talking bout it u_u...

Edited August 8, 2019 by Guest

[Guest]

 

[tater]

 

[RealKerbal3x]

Are they going to be attempting to recover the first stage on this flight, or will that have to wait for later flights?

[Rus-Evo]

1 hour ago, RealKerbal3x said:

Are they going to be attempting to recover the first stage on this flight, or will that have to wait for later flights?

Later flights.  This flight will have an HD data recorder called Brutus which will record rentry data, survive and be recovered.

[tater]

 

[tater]