Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

James Webb telescope reaches its final destination in space, million miles away

npr.org

Post reply on HN
Print view View original

311–320 of 350 posts

Re: James Webb telescope reaches its final destination in space, million miles away

#311

Post by beerandt »

whatshisface wrote: post #153
ethbr0 wrote: post #141

Earlier quoted context omitted.

And the Mercury program, which launched on adapted Redstone ICBMs [0], themselves improvements on V-2s. An unfunded project that never gets built is objectively worse than a military-funded project. [0] https://en.m.wikipedia.org/wiki/PGM-11_Redstone#Redstone_der...

If the military-funded project creates $1M worth of value using $1B of funds, the unfunded project is objectively better.

That's what army mapping service essentially did with early radar distance measuring projects. Huge expensive fleet of 18-wheeler trucks failure. And classical surveying methods beat it in every way at the time.

But it was the direct predecessor to microwave communications. It was just portable military distance measuring equipment (like the model-99 dme w/ ~1cm @50km) that used a signal they found easy to piggyback voice and data on. And included that in the field units.

AND 2nd, after a dozen or so more hugely expensive projects (ranging from failure to moderate success to "achieves objectives"), it led to the Airforce NAVSTAR program, which you know as... GPS.

So the question becomes: What was the actual "objective" value provided by those expensive initial radar experiments, despite failing to achieve their direct objective?

Re: James Webb telescope reaches its final destination in space, million miles away

#312

Post by wslack »

dboshardy wrote: post #150
Tenemo wrote: post #67

Earlier quoted context omitted.

Destin's channel is one of the older, best-known channels in the YT's educational sphere. Recently, the US Navy even let him on a multi-day tour of a nuclear submarine and tape classified information (later redacted). He himself worked in the military. I don't think that it's fair calling him a random youtuber, to me he seems like the perfect youtuber to interview such people (as Destin himself has a background in ro…

> the US Navy even let him on a multi-day tour of a nuclear submarine and tape classified information (later redacted) They _paid_ him to tour it. It was a marketing event for the US Navy to drive recruitment.

They neither paid him nor had edit approval on his content besides redacting classified information.

Re: James Webb telescope reaches its final destination in space, million miles away

#313

Post by wolverine876 »

pfdietz wrote: post #292
wolverine876 wrote: post #280

Earlier quoted context omitted.

What is that based on?

Which part? The bit with Nixon is well known (see, for example, John Logsdon's book "After Apollo?"). As for SLS, it's called the "Senate Launch System" for a reason. Shelby in particular has saved it, to the extent that work on propellant depots was targeted for extermination (no one in NASA is to utter the "D" word.) Depots and propellant transfer render irrelevant the SLS's supposed advantage of large payload mass…

The Nixon bit isn't well known, but thanks for the reference. I've never heard the rest. Is there a source?

It's easy to attribute political reasons to whatever Congress does, because Congress is filled with politicians. But members have other motives too, and private businesses, despite the hype, have plenty of corrupt and political motives - throwing contracts to allies and friends, undermining enemies, etc. - though they are far less transparent and are unchecked by the public or other institutions.

Re: James Webb telescope reaches its final destination in space, million miles away

#314

Post by wolverine876 »

adgjlsfhk1 wrote: post #299
wolverine876 wrote: post #279

Earlier quoted context omitted.

I've been wondering about that same issue and someone suggested that as a possibility. Do you know where NASA actually states it?

https://jwst-docs.stsci.edu/jwst-observatory-characteristics...

Muchas gracias! I've been looking for something like that. Another interesting bit I learned from the link:

> While orbits about the L2 point are inherently unstable, the orbit size is large and the orbital velocity is low (~1 km/s), so the orbit "decays" slowly. However, JWST's large sun shield, roughly the size of a tennis court, is subject to significant solar radiation pressure which results in both a force and a torque. The direction of solar force varies as the observatory's attitude changes from observation to observation. The solar torque is balanced by reaction wheels, but periodically, the accumulated momentum is dumped by firing thrusters.

If I understand correctly: JWST needs thrusters not to counteract a decaying orbit (too little energy), but to counteract accumulated momentum from solar radition (too much energy).

Re: James Webb telescope reaches its final destination in space, million miles away

#315

Post by wolverine876 »

avmich wrote: post #298
wolverine876 wrote: post #137

Earlier quoted context omitted.

It had one test flight. Hardly comparable to a system which had (six?) models fully deployed and operational.

Five Shuttles flew to space - Columbia, Challenger, Discovery, Atlantis, Endeavour. And Buran - the one which flew (other Soviet spaceplanes would have different names, so Buran is like Columbia, not like Space Shuttle) - didn't have e.g. the life support system; it was rather a development flight, than a demonstration of a complete system. Still Buran (as a combined name, like Energiya-Buran program) had some better…

> Buran (as a combined name, like Energiya-Buran program) had some better capabilities e.g. no toxic propellants onboard (Shuttle has to be chemically "pacified" after each landing) and longer orbital life (with cryogenics onboard).

My point is that they aren't capabilities, just specifications and promises for a cutting edge, developmental technology.

Re: James Webb telescope reaches its final destination in space, million miles away

#316

Post by wolverine876 »

TaylorAlexander wrote: post #293
wolverine876 wrote: post #278

Earlier quoted context omitted.

OT: I use they/their by default, unless I know otherwise, but what to do with other common gendered terms such as Mr./Ms./Mrs, Sir/Madam/Ma'am/Miss? These aren't avoidable problems: e.g., in the greeting for a business letter ('Dear ...'), or when getting the attention of a member of restaurant waitstaff whose name I don't know, etc. Someone needs to come up with a plausible set of gender-neutral terms. They/their/th…

Mostly I’ve just stopped using gendered terms. In a business letter even if the person is not trans you can’t assume Mr/Mrs/Ms unless you know. If their name is gender neutral or ambiguous I would say “Dear First Last,” though that’s even US/western-centric as not all cultures do it that way. If it’s a really important business letter you should probably find out the persons gender using some other channel. Also if t…

I think we can't avoid these issues and need to come up with solutions.

I've never seen Mx, so I think many people would wonder what it meant. Just "M." seems better and matches other usage (though outside contemporary English).

Re: James Webb telescope reaches its final destination in space, million miles away

#317

Post by cronix »

wolverine876 wrote: post #273
cronix wrote: post #163

Earlier quoted context omitted.

It's not unfounded, and they knew about it before it ever flew once. A family member was in the CIA at the time (later at NSA and RAND) and played a role after they were sent to the USSR after graduating college to study Russian (paid for by CIA, they know 8 languages). They translated the technical Russian Buran plans/documents and decoded them for our scientists to compare to their own, as well as help slip design…

They told you about these highly classified operations?

It's not classified anymore (I linked to a story that gives more info than I did), and you can be sure they won't tell me most details of things I ask about. If you think they sit there and tell me state secrets, think again lol. They're quite frustrating to talk to about this kind of stuff with because they won't answer most questions, or answer vaguely, and give absolutely no visual or audio indication of what they're thinking or what the answer might be. No wink-wink nod-nod. Completely dead-pan. You don't get to the level they were at by not understanding what you can and can't talk about. They don't slip up when drinking. They're still active in the community in the public sector side post retiring.

Re: James Webb telescope reaches its final destination in space, million miles away

#318

Post by beerandt »

zargon wrote: post #302
Buttons840 wrote: post #297

Earlier quoted context omitted.

> But back to military- it's not a coincidence that Hubble fit so perfectly in the shuttle cargo bay. I assume Hubble was built that size because it would fit? No coincidence indeed. And what does that have to do with the military?

> what does that have to do with the military? Hubble is a military spy satelite design.

Development of which presumably predated or coincided with setting the design parameters for the shuttle.

Re: James Webb telescope reaches its final destination in space, million miles away

#319

Post by dragonwriter »

TaylorAlexander wrote: post #293
wolverine876 wrote: post #278

Earlier quoted context omitted.

OT: I use they/their by default, unless I know otherwise, but what to do with other common gendered terms such as Mr./Ms./Mrs, Sir/Madam/Ma'am/Miss? These aren't avoidable problems: e.g., in the greeting for a business letter ('Dear ...'), or when getting the attention of a member of restaurant waitstaff whose name I don't know, etc. Someone needs to come up with a plausible set of gender-neutral terms. They/their/th…

Mostly I’ve just stopped using gendered terms. In a business letter even if the person is not trans you can’t assume Mr/Mrs/Ms unless you know. If their name is gender neutral or ambiguous I would say “Dear First Last,” though that’s even US/western-centric as not all cultures do it that way. If it’s a really important business letter you should probably find out the persons gender using some other channel. Also if t…

> If it’s a really important business letter you should probably find out the persons gender using some other channel.

Preferred form of address, not just gender, and this has been the rule for quite a long time. Even within the classical binary, there are all kinds of variations of status, preference, relationship with the sender, etc., that feed into that.

John Smith (a man) might be properly referred to in a salutation as any of:

“Mr. Smith”

”John”

“Dr. Smith”

“Your Excellency” (without the “Dear” that would prefer the others)

“Rev. Smith”

“Father Smith”

(And most of these correspond to one or more different forms that would be used in the main address, as well.)

Re: James Webb telescope reaches its final destination in space, million miles away

#320

Post by rhernandez35 »

dron57 wrote: post #309
BurningFrog wrote: post #243

Earlier quoted context omitted.

Persian and Chinese have, if I remember correctly, no gendered pronouns. No effects on gender equality seem observable.

Chinese has gendered pronouns in written form. The characters for he and she are written differently, but they are both pronounced the same way - tā. I assume that in some older form of Chinese the sounds must have been different, but they converged and people get by fine in spoken language.

It's actually the other way around. The 她 form was introduced in the relatively recent 1920s, partially to make it easier to translate Western texts.
Post reply on HN