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Comment Re:"have left Earth orbit" ?! (Score 1) 72

Pardon? Have you not seen the barge landings?

There are many aspects of a flight profile. Some are based on where you put the payload when it is in orbit. Others are the weight of the payload. As an example, 9's Payload for a GTO orbit is 5.5t when recovered on barge, and 8.3t for an expended mission. LEO orbit, 17.5 t if recovered, 22.8t expendable.

Just because some flight profiles can land at a pad or on a barge, does not mean that this happens in all cases.

References from paper :

A Survey of Launch Vehicle Recovery Techniques

Shraddha C.

Pankaj Priyadarshia

and Devendra Prakash Ghate

Institutes:

Vikram Sarabhai Space Centre, Thiruvananthapuram, 695022, Kerala, India

Indian Institute of Space Science and Technology, Thiruvananthapuram, 695547, Kerala, India

A pretty good read if you have the academic credentials to access it. Clear, at a reasonably high level so not too deep in the weeds, with all manner of different flight profiles for many rockets - including StarShip. And a lot more. Otherwise, I think it is a little premature to claim the success of Starship. The Falcon's are good reliable Rockets. Starship might end up a tad problematic.

Comment Re:Reusable rockets-- (Score 2) 72

Your assignment: Find out why reusable rockets are only useable for very specific launch envelopes. If you use them out of that launch envelope, there are just as disposable as the rockets you think are some sort of complete waste.

Interesting. I've never seen this claim made before; do you have a reference?

https://www.teslarati.com/spac... Forgive the link, it is a real rah-rah piece.

CEO Elon Musk says SpaceX has successfully expanded the envelope of orbital-class rocket recovery with its 50th booster landing, meaning that all Falcon boosters will have a better chance of safely returning to Earth from now on.

https://space-offshore.com/boo... "Falcon 9 missions may need to land on a droneship instead of RTLS due to the weight of the payload or the overall mission profile." I think you have academic access. Here is a good technical report on a lot of rockets that land after use. https://www.sciencedirect.com/.... You'll need academic credentials to download it. But it has a lot more info - and as part of the launch envelopes, there is constraint based on payload as well as direction. If you are going to land, there is a significant reduction in payload.

All of this is why I find it a little amusing that many among us find the most important aspect of launching these candles is the recovery.

tl,dr - where the rocket is going, what it is carrying has a big effect on recoverability. You can force things, reducing payload, or only sending the profiles to places where the first stage can make it back to the launch site, otherwise small extensions to allow it to make it back to a barge.

Comment Re:"have left Earth orbit" ?! (Score 1) 72

"Ladies and gentlemen, I am so, so excited to be able to tell you that for the first time since 1972 during Apollo 17, human beings have left Earth orbit," NASA's Dr Lori Glaze

I can expect some random science reporter to make this mistake, but bugger me, a senior NASA executive? It shows politics are far more important than any knowledge of science at NASA today.

Not only is Orion not leaving Earth Orbit (where the fuck do they think the moon is?) , it is not even entering lunar orbit. Orion's apogee has been pushed up for one orbit, but it's perigee is right down here.

Because Orbital mechanics is pretty difficult for most to grok. She does have bona fides, Doctorate in Environmental Science and Masters in Physics.

So I'm pretty certain that she well knows that Orion is still in orbit around the earth.

But just think about it. We have people in here who think that not re-using a rocket is some sort of crime, not thinking how that first stage can only return if it is close enough to the launch site. That if you want to go to the moon or a planet, you just point your Rocket at it and it's balls to the wall time. Among other misguided notions.

All said, She is an administrator, and I believe her excitement when she said that, so I'm not quite so willing to call her a political appointee. I'd call it an audio typo.

If it was me, I might say it was the first time humans have left Low Earth Orbit since 1972. And since it is a matter of providing soundbites, I would save the Perigee and Apogee part for later. Perigee and apogee are the more interesting parts from my perspective.

Comment Re:Is the bottle half full or half empty? (Score 1, Insightful) 72

But, There is absolutely nothing exceptional here: This has been already achieved almost 60 years ago, with much, much less technology available.

This gets brought up fairly often. And yes, we did it before. Why do it all again?

The learning curve is why. I can't imagine there is anyone from the Apollo project left at NASA. So a whole new group of people have to learn how to make things work. All those people sitting at their consoles are learning, re-learning after a fashion, what the Engineers learned in the 1960's.

It's all good!

Comment Re:Socialism (Score 1) 72

Yeah, it was cool watching those four $146,000,000/each RS-25 engines return to the landing pad. Stupid capitalists.

A lot of people have a lot of trouble understanding that returning a first stage to the launch site puts a huge constraint on where in orbit you can place that rocket's payload.

You can add a bit of flexibility if you return a rocket to a barge in the ocean - but not much. And when you use a barge, you are eating hard into whatever savings there are in capture and refurb.

The first stage has to have enough fuel to make it back to the landing pad or barge. If the launch envelope takes it out of that range, it's just another disposable rocket. As an indicator, people will notice I only mentioned the first stage. Because there's no good way to recover the second. The rocket is way too far downrange, the earth is rotating. There aren't many landing sites at that point.

Comment Re:Socialism (Score 0) 72

The government wimped out and pulled funding repeatedly on re-usable launch systems even ones that were showing success.

Your assignment: Find out why reusable rockets are only useable for very specific launch envelopes. If you use them out of that launch envelope, there are just as disposable as the rockets you think are some sort of complete waste. You are a really smart guy seems like you could teach us all about this stuff.

Comment Re: Thank AI (Score 1) 45

I still don't understand why any SBC application that is not emulating classic videogames needs more than 4 GB, let alone 8 GB.

A lot of people are using raspis as workstations, with any heavy lifting being done elsewhere. They are perfectly adequate for most normal daily tasks, silent, and use very little power. There's a lot to like about them, they're just overpriced for what little you're getting. If you didn't have to pay extra for basic features like an M.2 slot maybe they would be worth it. After you pay for a case, power supply (and they are picky as fuck about that) and so on, you're not saving any money compared to buying a MiniPC with better support and a richer set of available software. Raspi only has good vendor support compared to other poorly supported SBCs, all the heavy lifting is done by the community which often has to work around the pi foundation's failures.

Comment Laws are weird (Score 0) 140

In California, it's illegal to do this. We call it a speed trap, even though that already means something — cop hiding in some shitty spot where the speed limit suddenly and unexpectedly drops or whatever. I got busted with one of these in Jackson City, TX, a trivial little carbuncle on the asshole of a slightly shortcut route to Austin if you're heading East on the I-10, with a stop sign completely enveloped in a fucking tree that probably produces 50% of that shithole's revenue.

*ahem*

Anyhoo this CO scheme wouldn't be legal here in CA. And we'd also make a city cut a tree back if they wanted to keep writing speeding tickets based on a sign inside of the fucker.

Comment Re:Five years old (Score 1) 183

That's what I call DEI. Lesser qualified people hired or promoted in preference to merit because of identity politics. In irony, two of the best employees I ever worked with were women, hired using this metric. But that was accidental meritocracy. They would also have been hired for their ability in a non-checkbox world, not because of their sex.

The problem with many here is the automatic assumption that anyone not a white male was unqualified most likely because they are white males.

I understand completely. Many who are orgasming about a Woman and a "Black man because it checks off a box do not like White males, and want less of them doing things. Racism is in no way restricted to the dreaded white male. The people who would call themselves inclusive aer every bit as racist and sexist.

After all, when people say we need more women and people of color in a profession, they are exactly saying they want less White men.

P.S. Race is exactly the biggest social construct ever invented. I'll believe that human races exist when speciation happens, when a human from one group cannot mate and produce offspring.

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