The James Webb Space Telescope and stuff

[StrandedonEarth]

35 minutes ago, HebaruSan said:

Why would Congress prefer to get less bang for their buck?

"What? And then you want money to operate it for twenty years? We can't commit for that long!"

[HebaruSan]

A longer functional life doesn't obligate Congress to do anything. A shorter one ends the program.

[magnemoe]

1 hour ago, HebaruSan said:

Why would Congress prefer to get less bang for their buck?

On the other hand, I'm guessing promising 20 years when there's a chance you might only get 5 would have been a risky career move.

This, the operational cost of robotic space missions is pretty low, as in some engines monitoring it and maintaining an data link. 
 

[wumpus]

22 hours ago, magnemoe said:

This, the operational cost of robotic space missions is pretty low, as in some engines monitoring it and maintaining an data link. 
 

I doubt Hubble is all that cheap, although most of the issues involve managing who gets to use the telescope.  From the descriptions I've heard, they mostly involved having a seriously skilled team on call, and having them around (possibly on zoom) during the moments when they get deep space network time.  And don't be too surprised if you wind up racking up a lot of highly billable extra hours if something goes wrong (from descriptions from someone on the inside of one of these, it seems each time they connect to the deep space network nobody is ever sure the gyros, radios, and assorted gear will all work at the same time.

On 1/22/2022 at 11:34 AM, StrandedonEarth said:

"What? And then you want money to operate it for twenty years? We can't commit for that long!"

Congress is typically the other way around.  You want to promise low up front costs and pack the bigger expenses when the sunk cost fallacy kicks in.  See the entire history of the Shuttle, and ask yourself how else NASA could get 100+ crewed missions in the 80s and 90s.

[JoeSchmuckatelli]

 

Quote

On Monday, Jan. 24, engineers plan to instruct NASA’s James Webb Space Telescope to complete a final correction burn that will place it into its desired orbit, nearly 1 million miles away from the Earth at what is called the second Sun-Earth Lagrange point, or “L2” for short.

James Webb Space Telescope (nasa.gov)
 

Quote

 

Webb’s orbit around L2 is larger in size than the Moon’s orbit around Earth! 

...

by orbiting rather than being exactly at L2, Webb will never have the Sun eclipsed by Earth, which is necessary for Webb’s thermal stability and for power generation. 

 

 

 

 

[NFUN]

God, 99.9% of the way there. I need to stop staring at this countdown

[Ignath]

JWST orbital insertion burn successful:

https://blogs.nasa.gov/webb/

[JoeSchmuckatelli]

Thank the noodly appendaged one (or whatever deity might apply).

[HebaruSan]

7 minutes ago, Ignath said:

JWST orbital insertion burn successful:

https://blogs.nasa.gov/webb/

Wow!

Quote

The final mid-course burn added only about 3.6 miles per hour (1.6 meters per second) – a mere walking pace – to Webb’s speed, which was all that was needed to send it to its preferred “halo” orbit around the L2 point.

Just in case anyone isn't tired of seeing it yet, the orbit:

Edited January 24, 2022 by HebaruSan

[Entropian]

3 hours ago, HebaruSan said:

tired of seeing it yet

How can a halo orbit ever possibly become boring?  Remember you're on a spaceflight-focused forum

[JoeSchmuckatelli]

3 hours ago, HebaruSan said:

Just in case anyone isn't tired of seeing it yet, the orbit:

.

The thing I don't get, is that given L2 is less stable than L4 / L5... how the orbit actually works.  Absent correcting the orbit (drift) several times a year, I can't see how the wobbling solar orbit is a stable one.  Looks to me that at some point it should 'fall off the hill' and just keep going.

[HebaruSan]

12 minutes ago, JoeSchmuckatelli said:

The thing I don't get, is that given L2 is less stable than L4 / L5... how the orbit actually works.  Absent correcting the orbit (drift) several times a year, I can't see how the wobbling solar orbit is a stable one.  Looks to me that at some point it should 'fall off the hill' and just keep going.

Wikipedia says they'll spend 2.5 m/s per year on stationkeeping, but I think the idea of the "halo" orbit may be to use its inclination to cancel out opposing tendencies of drift (the northern half is further from the sun, with outward drift, and the southern half is closer, with inward drift):

Edited January 24, 2022 by HebaruSan

[Kerbart]

On 1/22/2022 at 10:56 AM, HebaruSan said:

Why would Congress prefer to get less bang for their buck?

Because the "ground crew" comes with an annual budget cost and that cost is lower for five years than for twenty. Of course that'd be stupid after sinking billions of dollars into launching the thing but I doubt anyone will dare to accuse congress of taking a long term view on things.

[HebaruSan]

4 minutes ago, Kerbart said:

Because the "ground crew" comes with an annual budget cost and that cost is lower for five years than for twenty. Of course that'd be stupid after sinking billions of dollars into launching the thing but I doubt anyone will dare to accuse congress of taking a long term view on things.

Again, if Congress doesn't want to pay for that after five years, they can vote to cut the funding even if the telescope is still working. Why hope for a device failure to force their hands if that's what they want already?

Remember, we're speculating about answers to the question, "Why did the JWST project managers only promise 5 years when now we're getting 20?" For the ground crew funding explanation to work out, we have to imagine that if some initial presentation said "20 years," somebody would have gotten nervous because that would be too much science and then cut it to say "5 years" with the expectation of that improving their chances of getting approval. Never say never, I guess, but this seems far more convoluted than, "I didn't want to get fired if something went wrong and we got less than 20 years."

Edited January 25, 2022 by HebaruSan

[Minmus Taster]

Am I the only one who still can't believe it actually happened?

It's crazy to think it actually happened, and may work!

[Jacke]

2 minutes ago, Minmus Taster said:

Am I the only one who still can't believe it actually happened?

It's crazy to think it actually happened, and may work!

Pretty picture, but the JWST would never take such an attitude.  The mirror is always in cold darkness.

[HebaruSan]

40 minutes ago, Jacke said:

Pretty picture, but the JWST would never take such an attitude.  The mirror is always in cold darkness.

Hopefully it also won't be wandering out to Jupiter.

[Entropian]

5 hours ago, Minmus Taster said:

Am I the only one who still can't believe it actually happened?

It's crazy to think it actually happened, and may work!

I love how there's obvious nebulae visible in the background

[Admiral Fluffy]

13 hours ago, Minmus Taster said:

Am I the only one who still can't believe it actually happened?

It's crazy to think it actually happened, and may work!

Looks awfully dangerous. Why did we put it right there?

[JoeSchmuckatelli]

7 minutes ago, Admiral Fluffy said:

Looks awfully dangerous. Why did we put it right there?

The rocks shield it from the sun?

Although if the inner ring is a blast wave...

The more I look at it, I realize what an exciting locale it is.  Clearly has two suns (due to the light directions) and is actively planet forming; likely to be a Heavy Bombardment period.  Would be fascinating to study.

 

Not sure Webb is the best craft to visit - but nice to see that it's still operational in a time when FTL is possible!

Edited January 25, 2022 by JoeSchmuckatelli

[Beccab]

4 minutes ago, JoeSchmuckatelli said:

The more I look at it, I realize what an exciting locale it is.  Clearly has two suns (due to the light directions) and is actively planet forming; likely to be a Heavy Bombardment period.  Would be fascinating to study.

Not only that, but the second star is also apparently invisible while still emitting light. Invisible-class stars are the best

[JoeSchmuckatelli]

https://youtu.be/60ijH2EWI5g?t=66

[kerbiloid]

Even telescopes are running from your Earth due to Starlink.

[Nuke]

9 hours ago, kerbiloid said:

Even telescopes are running from your Earth due to Starlink.

i always suspect that starlink was intended to drum up demand for launch services for space telescopes. 

i wonder what the feasibility of using the receivers on the starlink constellation as a ginormous radio telescope. they could use their laser interconnects to move the data to a small number of designated downlink sats. 

Edited January 26, 2022 by Nuke

[Gargamel]

17 hours ago, JoeSchmuckatelli said:

The rocks shield it from the sun?

Although if the inner ring is a blast wave...

The more I look at it, I realize what an exciting locale it is.  Clearly has two suns (due to the light directions) and is actively planet forming; likely to be a Heavy Bombardment period.  Would be fascinating to study.

 

Not sure Webb is the best craft to visit - but nice to see that it's still operational in a time when FTL is possible!

Must be related to this actual official NASA photo of JWST.    I mean it’s in their parking lot, so it must be official.   
 

 

7 hours ago, Nuke said:

i wonder what the feasibility of using the receivers on the starlink constellation as a ginormous radio telescope. they could use their laser interconnects to move the data to a small number of designated downlink sats. 

I’ve seen DIY projects using satellite tv dishes for home radio astronomy.   I don’t see why this wouldn’t scale up nicely.