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Artemis II Launch Day Updates

nasa.gov

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Re: Artemis II Launch Day Updates

#721

Post by marcus_holmes »

p1mrx wrote: post #715
marcus_holmes wrote: post #708

Earlier quoted context omitted.

I am in a gravitational field. I have no idea what my acceleration is, I just know that I feel 1G (I could be falling in a stronger gravity and only feel 1G, or I could be climbing in a weaker gravity and feel 1G). The only way of determining it is to see if I'm moving relative to the stuff around me. Even then, that's not definite - I could be in an elevator and everything around me is also accelerating. I'm not dis…

According to general relativity, you (and the ground) are accelerating at 1g, and feel weight because your inertia resists that acceleration. If you jump off a cliff, you'll stop accelerating for a bit, until the ground hits you. Edit to reply: > I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating? You are accelerating at 1g through curved spacetime. Newtonian "sp…

I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating?

Re: Artemis II Launch Day Updates

#722

Post by marcus_holmes »

qubitcoder wrote: post #712
marcus_holmes wrote: post #708

Earlier quoted context omitted.

I am in a gravitational field. I have no idea what my acceleration is, I just know that I feel 1G (I could be falling in a stronger gravity and only feel 1G, or I could be climbing in a weaker gravity and feel 1G). The only way of determining it is to see if I'm moving relative to the stuff around me. Even then, that's not definite - I could be in an elevator and everything around me is also accelerating. I'm not dis…

You can always hold an accelerometer in your hand. If you did so now, assuming you're on Earth's surface, it'd register approximately 9.8m/s/s pointing in the upward direction. You could also perform one of many historical experiments, such as dropping an object from an elevated height with careful timing, or rolling a round ball down a gently sloped track, and so on.

Yes, because there is no way of differentiating between acceleration and gravity. Which was my point.

Re: Artemis II Launch Day Updates

#724

Post by FabHK »

xattt wrote: post #642
JumpCrisscross wrote: post #509

Earlier quoted context omitted.

> Is Artemis III the one with a lander? Not anymore. Artemis III is now a LEO systems check [1]. Comparable to Apollo 9. (Side note: when did we switch from Arabic to Roman numerals?) [1] https://en.wikipedia.org/wiki/Artemis_III

There’s definitely “notation-fluidity” in Apollo mission patches. 10 is Roman, 11 is Arabic, 12 & 13 are Roman again.

Which is weird, because "X", "10", "XI", "XII", "12", "XIII", "13" are all unambiguous, while "11" could be read as "II" = 2 depending on the font. In other words, they switched exactly as to maximise ambiguity.

Re: Artemis II Launch Day Updates

#725

Post by FabHK »

casefields wrote: post #719
sd9 wrote: post #320

Minutes after launch they reached "ten thousand miles per hour". That's 2.78 miles per second. Nuts. No doubt the speeds go even higher later too. I'm sure people here are already familiar with the speeds these things go, but that's the first time I've confronted a fact like that and it blew me away.

A Dodge Challenger SRT Demon can also reach 10,000mph in 4 minutes if it held its 0-60 acceleration over the whole span. So yes, you can buy a car today that'll let you feel the G's like you're a space pilot.

One fact that I found unintuitive (while we're at cars doing things they can't):

If you could drive your car straight up vertically, you'd have to cruise just for an hour or so at 100 km/h (<65 mph) until you reached space. It's not that far.

Re: Artemis II Launch Day Updates

#726

Post by dotancohen »

gammarator wrote: post #687
areoform wrote: post #207

Earlier quoted context omitted.

Yes, and more! > Apollo was over three orders of magnitude more efficient in producing scientific papers per day of fieldwork than are the MERs. This is essentially the same as Squyres’ (2005) intuitive estimate given above, and is consistent with the more quantitative analogue fieldwork tests reported by Snook et al. (2007). Scientific papers are a pretty poor measure of productivity so here's another one. We know a…

You’ve got to normalize by dollars spent, though.

If your goal is to save money, just ignore the moon. This is not the west indies to be exploited, at least not yet. These are scientific missions, not economic missions.

The philosopher Randall Munroe once wrote:

  > The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space - each discovered, studied, and remembered by the ones who made the irrational decision.

Re: Artemis II Launch Day Updates

#728

Post by dylan604 »

qingcharles wrote: post #672
dylan604 wrote: post #513

Earlier quoted context omitted.

wow, that shot of it sitting on the pad is much cleaner than I'd have expected from that phone. i'm envious

I cheated somewhat. I had some good binoculars with me that day and I was juggling those in one hand while holding the iPhone to the eyepiece :) (and I checked, it was iPhone 4 not 5)

I was wondering how the zoom was so clear. However, I'm familiar with the struggle of shooting that way. I don't have a phone mount for my telescope, but with enough struggle, I can get a decent pic from the viewfinder on my phone. So don't play it off as cheating. It was a bit of skill to get both the binocs and the phone steady and aligned enough to get it.

Either way, it's a shot not everyone is going to have posted to their socials.

Re: Artemis II Launch Day Updates

#729

Post by dylan604 »

ls612 wrote: post #677
dylan604 wrote: post #607

Earlier quoted context omitted.

Artemis II won't fly by the moon until Day 6, but it only took Apollo 8 to Day 4 to get to the moon. Looking at the wiki for Apollo 8, it shows the moon was 218k miles at launch while they said the moon is currently 240k, so it still looks like Apollo was moving faster than Artemis.

Apollo put a lot more burden on the Service Module than Artemis plans to put on the Orion. Apollo put the CSM/LM into a low lunar orbit while Artemis plans to put Orion into a high lunar orbit and make the Starship carry a lot more delta-V to land from a much higher velocity (and then accelerate back up to that velocity when coming back). On top of that there weren’t really solar panels in the 1960s so the Service Mo…

Admittedly, I let this launch sneak up on me, and I just haven't paid attention to the flight details. Thanks

Re: Artemis II Launch Day Updates

#730

Post by dylan604 »

dotancohen wrote: post #718
dylan604 wrote: post #618

Earlier quoted context omitted.

That's what I thought standing at the rim of the Grand Canyon. Pictures just do not do it justice. Same thing with Starship. My brain knows it's massive, yet feels underwhelmed looking at it on video. Musk should let his ego build replica Saturn V and a Shuttle next the Starship launch pad so there will be proper perspective available

Have you been to the rocket garden at KSC? The Saturn V isn't vertical, but they've got almost everything from the Redstone and later vertical. I was in Florida in 2018 and I think they were getting ready to display a pair of SRBs. They did have Atlantis inside, too. And of course a horizontal Saturn V. I saw that Saturn V as a child once, too. I think that the Saturn V really made me the person that I am today. Seei…

I've never been to KSC. I've been to Houston a few times. I couldn't imagine trying to have a Saturn V permanently standing would be an easy feat with both locations susceptible to hurricanes and tornadoes. Walking the length of it is still pretty impressive.

I come from a construction family, so I'd put some of the famous sky scrapers in that category too. Especially thinking about the crazy beam walkers like that famous photo of the guys riding the I-beam up eating their lunch on the way up.

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