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From the April 15, 2021 Everyday Astronaut video A chat with Rocket Lab's CEO Peter Beck about Neutron, Electron recovery and Rocket Lab's future! linked below (mostly from closed captions, small adjustments for simultaneous talking):

Beck: And Wallops is a wonderful site. We have great relationships with everybody there. And you can achieve a large amount of trajectories, including synchronous, out of Wallops, which is really advantageous.

Everyday: Yeah, you can do a little dogleg down there and sill go, that’s... how big of a... that’s gotta be a fairly substantial payload penalty though? Especially if you’re doing propulsive landing… and a dogleg maneuver from Wallops

Beck: It’s actually not too bad. I mean, it’s better than the Cape, so yeah, it’s not too bad at all.

Everyday: Is that because the Cape… you get to fly substantially far east and then do the dogleg, just not hav(ing) to go as far east, you can go more southernly?

Beck: Correct. Yeah. Correct. Yep, yep.

Question: What's the penalty for Neutron dog-legging from Wallops to synchronous? From what's known or can be inferred about the Rocket Lab Neutron launch vehicle (e.g. ~8 tons to LEO) can a delta-v for the dogleg or a payload penalty in tons be inferred?

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    $\begingroup$ It would be helpful to have some usage guidance on the new dogleg-maneuver tag. $\endgroup$
    – DrSheldon
    Aug 9, 2021 at 4:42
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    $\begingroup$ @DrSheldon all tags can benefit at least somewhat from usage guidance; I have several recent questions in meta that mention some in great need of it. I'm hard-pressed to see how a noun as specific and unique as dog-leg-maneuver in the context of spaceflight could be in imminent danger of being misused. $\endgroup$
    – uhoh
    Aug 9, 2021 at 6:47
  • $\begingroup$ @DrSheldon I thought about it for a while but I'm not sure how to write an exact definition for a dogleg maneuver, and I'm not sure if I know it when I see it is good for a tag definition. Perhaps one way to narrow this down is to literally narrow down the scope of what is and what is not thought to be a dogleg maneuver. To that end, I’ve started. Most dog-legged launch? $\endgroup$
    – uhoh
    Aug 10, 2021 at 1:41

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From the Antares Rocket User's Manual, which is also launched from Wallops (The same pad actually), and similar size to Neutron, we can get an idea of the performance. Looking at the 600 km orbital altitude, the mass drops from 6500 kg to 3500 kg. So there is certainly a large penalty, but still doable.

Of some note is that the dogleg is actually not as bad as it seems, because of the rotation of the Earth which needs to be cancelled out. An Atlas V 401 rocket when launched in to a LEO 28.5 degree orbit vs one launched to SSO goes from 8715 kg to 6640 kg, according to NASA's Launch Vehicle Performance calculator. For comparison, Falcon 9 RTLS goes from 11000 kg to 8300 kg for the same orbits.

It is likely this will be reduced for Neutron, because Neutron's upper stage will be more efficient than Antares's solid upper stage, but it provides a reasonable close approximation.

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    $\begingroup$ Remember that that difference also includes the 435m/s difference between an SSO vs. a LEO-at-SSO-Altitude at launchpad inclination. launchercalculator.com says the payload to SSO from WFF with this rocket is 4790kg, vs 6024kg for same altitude circular LEO at 38degrees. (don't know if their calc includes the dogleg, i suspect not) $\endgroup$
    – CuteKItty_pleaseStopBArking
    Nov 24, 2021 at 18:12

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