Live data from Hacker News

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

npr.org

251–260 of 350 posts

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

#251

Earlier quoted context omitted.

Its nice to be able to design things around Sci-Fi. However, still in 2022, there is no spacecraft that allows EVAs anywhere.

The occupants of the ISS beg to differ. http://spaceref.com/iss/eva.html

I was unaware that the ISS was a spacecraft. I was under the impression it was a space station.

Im also unaware that the ISS is able to reach L2 or really any orbit other than LEO roughly 400km in altitude.

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

#252
post #142

Earlier quoted context omitted.

> Also it is a good idea to use metric units for science articles. It's not if you're writing for an American audience that's more familar with imperial units.

We should just define that outer space uses metric units. The average american won't know the difference between "a million miles" and "a million kilometers", because they're both way beyond the realm of practical experience.

As an American, about 1.6.

600,000 kilometers is 1.5 times as far from Earth as the Moon. Interesting to think how much longer it took Webb to cover that distance than Apollo. A consequence of not being able to slow down under power.

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

#253

Question; why is the Where is Webb page saying current speed is .1255 miles/second? There's a blurb in the explainer that says that speed is Earth relative. https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?s=...

I always find mentions of "speed" of spaceships in the press very strange: they never specify the reference frame.

Right? Sitting still we are 1,037 mph at the equator. And then you can consider relative to our sun, or galactic core, etc. https://www.space.com/33527-how-fast-is-earth-moving.html

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

#254

Question; why is the Where is Webb page saying current speed is .1255 miles/second? There's a blurb in the explainer that says that speed is Earth relative. https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?s=...

It's in orbit round L2, not stationary relative to Earth. Video as linked by another comment: https://www.youtube.com/watch?v=6cUe4oMk69E&list=TLGG8tIphgp...

Watching that video it seems to me relative to earth the speed is Zero? Distance to the earth is not changing. Relative to other things sure it's moving around.

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

#255

I'm a little embarrassed to say this and I don't know exactly what I pictured in my head, but I had no idea these telescopes were so big[1]. I guess I never saw one pictured next to a human. I've only seen pictures of satellites being worked on so I expected something more human sized? It seems so stupid now, especially since earth telescopes are huge. [1] https://svs.gsfc.nasa.gov/vis/a010000/a013500/a013522/JWST_v.…

The nasa image[1] of employees with the scale model provides a better sense.

[1] https://www.astronomie.nl/upload/750x498/images/Telescopen/J...

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

#256

Earlier quoted context omitted.

I don't get the need to bag on the Shuttle program here. The Shuttle was designed nearly 50 years ago with drastically different requirements and stakeholders.

It's because people still defend it, or imply it was more worthy than it actually was. And because the same mistake is being repeated right now (SLS).

SLS isn’t the currently-in-development spacecraft that utilizes hundreds of ceramic tiles to aerobrake through the atmosphere. SLS is basically a modern Saturn V. A complete departure from the Shuttle, with the exception of-re-using the SRB design. On paper a very conservative choice.

Starship looks a lot like Shuttle 2.0 to me. Except the landing is somehow even more terrifying.

As far as I can tell the idea with Starship is to design a vehicle that can survive losing a few tiles because that’s inevitable.

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

#257

Earlier quoted context omitted.

The occupants of the ISS beg to differ. http://spaceref.com/iss/eva.html

I was unaware that the ISS was a spacecraft. I was under the impression it was a space station. Im also unaware that the ISS is able to reach L2 or really any orbit other than LEO roughly 400km in altitude.

> I was unaware that the ISS was a spacecraft.

I can't really help that, but here is a nice page from NASA:

https://www.nasa.gov/audience/forstudents/5-8/features/nasa-...

"The International Space Station is a large spacecraft in orbit around Earth."

> Im also unaware that the ISS is able to reach L2 or really any orbit other than LEO roughly 400km in altitude.

You can tow it wherever you want, provided you attach a suitable propulsion device. That's also how it stays in that orbit, every now and then they boost it back up to offset the orbital decay.

Also: in space assembly could take place in orbit and then when the device is complete it can be sent off to L2. The problem with such a scheme is when things break down after the transit to L2.

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

#259
post #203

Earlier quoted context omitted.

The space shuttle blows my mind every time I see one. It's huge - the size of an airliner - and would glide back at Mach 25. It's a humbling level of accomplishment.

You can actually go see Endeavor in real life at the L.A. Science Center. Admission is like $2. Regardless of the size, the spectacle is breathtaking.

Standing next to a shuttle is a humbling experience. On TV it looks like, well, a plane, but in person, it's just massive. The exit hatch (I assume), the one you would expect an astronaut to exit while fully equipped and layered, looks like the size of a bottle opening.

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

#260

Earlier quoted context omitted.

original plan was smaller, but military had a mission in mind that required it be bigger, so they went bigger to get military buy in. And of course the imagined mission never happened. I wonder how much money would have been saved!

The space shuttle is a sad story. On the one hand the military’s money made it possible but they also influenced the design in a very bad way.

OTOH, they also influenced it in many good ways that you don't hear about.

E.g., my astronomy professor mentioned to me in a conversation that the original design for the Hubble was smaller due to expected budget, but that it got up-sized because it turned out that they could piggy-back off of other relevant military development, and iirc, that went beyond just the larger available size of the shuttle bay.

Post reply on HN