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rocketsocks t1_jdw95o9 wrote

Reply to comment by Charming_Ad_4 in Rocket Lab targets $50 million launch price for Neutron rocket to challenge SpaceX’s Falcon 9 by cnbc_official

Landing a booster from an orbital rocket is a greater challenge than a sub-orbital rocket, but not insanely so. SpaceX took time to figure out how to do it because they were trying many different methods and they were trying to do the R&D extremely cheaply. And it worked. Today we have the benefit of hindsight, and companies like Rocket Lab have the benefit of being able to follow in SpaceX's footsteps, without having to steal their confidential trade secrets. Some lessons on the process are publicly known, such as the use of an entry burn to moderate speed, and so on. Some lessons are actually publicly available data because NASA commissioned SpaceX to gather data on supersonic retropropulsion to inform future Mars landings. SpaceX's "secret sauce" has never been trade secrets, it's always been it's ability to execute operationally and get things done.

Additionally, Neutron is attempting an easier flight profile than Falcon 9, it's not doing barge landings and instead focusing solely on returning to the launch site. SpaceX succeeded with their first ever attempt at an RTLS landing, which was their first successful landing overall, and their success rate for ground landings was very high (100% in fact) even while they were improving the reliability of drone ship landings. It's just an easier and simpler flight profile. But it requires you design the rocket from the get go with that in mind (because you need enough performance margin), which Neutron and Starship have been.

SpaceX may be able to get things done, but Starship is a tremendous amount to bite off all at once. The launch tower is different, the landing profiles are different, there is upper stage atmospheric re-entry and controlled descent, there is upper stage landing, there is the thermal protective system on the upper stage, there is orbital propellant transfer, and on and on and on. Getting all of these things working is required in order to meet their Artemis Program Starship-HLS commitments. Without those commitments it's possible that Starship could see commercial service in a sort of "early access" mode where they were still working on upper stage landings and reuse, but because of the Starship-HLS contract it's very likely that'll be a secondary priority.

I'm not sure why people have this idea that Starship is going to be easy or why Neutron is going to be hard. Neutron vs. Starship are just fundamentally different things. Neutron is a much shorter race to "run" compared to Starship, it's a sprint vs. a marathon. Even if SpaceX is much faster at working through Starship design and development issues than Rocket Lab is with Neutron they just have much, much longer to go.

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seanflyon t1_jdwrme1 wrote

Are you calling the DC-X a suborbital rocket? That seems like a stretch, it never made it to space or close. DC-XA got 3140 meters up. That is about a quarter as high as a normal commercial aircraft flights.

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Charming_Ad_4 t1_jdza5zc wrote

It is insanely so. x100 more difficult. If it wasn't, someone else would have landed an orbital rocket by now, when they landed a suborbital in the 90s.

What many different methods of landing the rocket did they try? Does Rocket Lab knows all of them?

Oh wow, SpaceX secret sauce is getting things done and execute!! Wow that's not what we call secret sauce!

I'm not sure you've noticed, that Gwenn and Elon have both said they will do around 100 Starship launches before land on the moon with HLS. So...that kind of mean a hell of a lot of launches with Starlink and customer's sats. And they don't need orbital refilling for that.

Cause SpaceX does know how to land and reuse. And Starship's design is made with lessons learned from F9. Rocket Lab and Neutron don't have lessons learned. That's why so many people believe Starship is easier for SpaceX than Neutron for Rocket Lab. And SpaceX does work faster. Rocket Lab will need at least 3 years for first launch, another 2 for first landing, another 2 for first reuse. So 7 years to make reusability and that's the minimum time. Starship will fly in a couple of months. So....

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rocketsocks t1_je1ae4y wrote

> It is insanely so. x100 more difficult. If it wasn't, someone else would have landed an orbital rocket by now, when they landed a suborbital in the 90s.

It's not insanely difficult, it just hasn't been tried very often. Every program that tried VTVL rocket landing has succeeded (DC-XA, Blue Origin, SpaceX). It just hasn't been tried much. The reason it hasn't been tried much is because reuse hasn't been prioritized or done very pragmatically. Prior to the 2000s most RLV development focused on unrealistic designs such as the Shuttle or SSTOs, not on simple two stage launchers with booster reuse. More so, there hasn't been much competition in the launch vehicle space until the 2000s, for a variety of reasons, so extreme cost competitiveness wasn't a major factor until then.

Additionally, there are many natural optimizations that have traditionally been made with expendable launchers which deoptimize them for booster reuse. Expendable launchers tend to have simpler, lower cost first stages with only a few engines (Delta IV, Atlas V, and Ariane 5 only have one), while the majority of the cost and complexity is pushed into the upper stage. This makes first stage reuse much harder, especially in the VTVL configuration (it's very difficult to throttle down a single huge engine vs. simply turning off extra engines) and it makes it useless, as you end up simply saving the cost of expending the cheapest part of the rocket. You have to go into two stage launch vehicle design while planning ahead for VTVL first stage reuse to actually make it worthwhile. The genius of SpaceX was that they made very pragmatic design decisions that aimed at reusability straight out of the gate, and they figured out how to do the R&D for reuse within the context of paying commercial customer flights, making use of "thrown away" hardware that created the equivalent of a billion dollar funding stream. But much of that can be copied by anyone paying attention. SpaceX may have some degree of "secret sauce" that drives their success, but simply achieving VTVL reusable rockets is not it alone.

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