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James Webb space telescope set to launch on Christmas Eve.

https://www.sciencealert.com/there-was-a-major-unexpected-benefit-to-james-webb-s-christmas-launch

After a detailed analysis of where the James Webb Space Telescope is now (29 December 2021) and how it got there, NASA determined the observatory should have enough propellant to operate in space for significantly more than 10 years in space.

Webb's mission lifetime was designed to be at least 5-1/2 years, and mission engineers and scientists were hoping for closer to 10 years.

The "significantly more than 10 years" announced this week comes from two factors: the precision of the Ariane 5 launch on December 25, which experts say exceeded the requirements needed to put Webb on the right path.

And now, because of how precise JWST's trajectory has been, the first two mid-course correction maneuvers took significantly less fuel than expected.

The first course correction was a 65-minute burn that took place about 12.5 hours after launch. While 65 minutes sounds like a long time, a burn lasting as long as 3 hours could have been required.

That first burn put the observatory on an even more precise path and added approximately 45 mph (20 meters/sec) to the observatory's speed. A second shorter correction maneuver on December 27 added around 6.3 mph (2.8 meters/sec) to the speed.

JWST's lifetime is limited by the amount of fuel used for getting to L2 and maintaining its orbit, and also by the possibility that Webb's components will degrade over time in the harsh environment of space.

The precise trajectory the observatory is now on means more propellant for orbit maintenance and momentum management down the road, which means a longer operational lifetime.
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Sunshield tensioning might or might not begin today. It's understandable that they adjust the schedule according to the environmental conditions measured by the Webb.

Taking advantage of its flexible commissioning schedule, the Webb team has decided to focus today on optimizing Webb’s power systems while learning more about how the observatory behaves in space. As a result, the Webb mission operations team has moved the beginning of sunshield tensioning activities to no earlier than tomorrow, Monday, Jan. 3. This will ensure Webb is in prime condition to begin the next major deployment step in its unfolding process.
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Update: NASA Plans Coverage of Webb Space Telescope Deployments | NASA
James Webb Space Telescope (nasa.gov)

ETA: The sunshield is now fully deployed.
James Webb Space Telescope: Sun shield is fully deployed - BBC News
 
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OMG this is exciting. When will it be fully up and ready to stargaze?
I do worry about it being so far away from Earth though.
 
The telescope will continue calibrations and adjustments until six-months post-launch, at which point it'll begin its scientific observations. They're planning to expedite the release of the first few images when the telescope is commissioned, to show off what it can do to the public. They do something similar with other landers and space-probes, making sure a few images are ready to put out right away, even if the bulk of the data will take a while to process.

  • In the first month [post-launch]: Telescope deployment, cooldown, instrument turn-on, and insertion into orbit around L2. During the second week after launch we will finish deploying the telescope structures by unfolding and latching the secondary mirror tripod and rotating and latching the two primary mirror wings. Note that the telescope and scientific instruments will start to cool rapidly in the shade of the sunshield, but it will take several weeks for them to cool all the way down and reach stable temperatures. This cooldown will be carefully controlled with strategically-placed electric heater strips so that everything shrinks carefully and so that water trapped inside parts of the observatory can escape as gas to the vacuum of space and not freeze as ice onto mirrors or detectors, which would degrade scientific performance. We will unlock all the primary mirror segments and the secondary mirror and verify that we can move them. Near the end of the first month, we will execute the last mid-course maneuver to insert into the optimum orbit around L2. During this time we will also power-up the scientific instrument systems. The remaining five months of commissioning will be all about aligning the optics and calibrating the scientific instruments.
  • In the second, third and fourth months: Initial optics checkouts, and telescope alignment. Using the Fine Guidance Sensor, we will point Webb at a single bright star and demonstrate that the observatory can acquire and lock onto targets, and we will take data mainly with NIRCam. But because the primary mirror segments have yet to be aligned to work as a single mirror, there will be up to 18 distorted images of the same single target star. We will then embark on the long process of aligning all the telescope optics, beginning with identifying which primary mirror segment goes with which image by moving each segment one at a time and ending a few months later with all the segments aligned as one and the secondary mirror aligned optimally. Cooldown will effectively end and the cryocooler will start running at its lowest temperature and MIRI can start taking good data too.
  • In the fifth and sixth months: Calibration and completion of commissioning. We will meticulously calibrate all of the scientific instruments’ many modes of operation while observing representative targets, and we will demonstrate the ability to track “moving” targets, which are nearby objects like asteroids, comets, moons, and planets in our own solar system. We will make “Early Release Observations,” to be revealed right after commissioning is over, that will showcase the capabilities of the observatory.

  • After six months: “Science operations!” Webb will begin its science mission and start to conduct routine science operations.
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Yeah, I gather it'll be up to 6 months before real scientific observation starts. Of course, any published images will be false colour ones because of the spectral range of the instrument. Human eyes don't see in the same wavelength range. Webb's range is from about 0.6 μm to 28 μm (red to mid-infrared). For comparison, Hubble's range is from 0.1 μm to 2.5 μm (ultraviolet to near infrared). Humans generally perceive light from 0.4 μm to 0.74 μm. However, depicting Webb's images merely as shades of pink probably wouldn't go down well with the public who've paid $10 billion.

The resolving power of Webb will be similar to or less than but not greater than Hubble except in the red to near infrared. Angular resolution is proportional to wavelength divided by mirror diameter. Hence Webb's primary mirror is wide for good reason.
 
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Webb could function without the side mirrors that were swung into place over the last couple of days but the angular resolution would have been diminished in one dimension and fewer photons could be collected. It's a remarkable piece of engineering all things considered.
 
Depends on the repair, at the moment, it just needs some more fuel in around ish 10 years. That can be done by a robot. .. have to invent said robot, but they are thinking about it.
If something is broken and needs a human touch? Not at the moment, nothing can get to the moon, let alone L2. Now give it 5 years? Then you have Starship, possibly Artimis, and could go out there yes.
 
valkyrie013 said:
Depends on the repair, at the moment, it just needs some more fuel in around ish 10 years. That can be done by a robot. .. have to invent said robot, but they are thinking about it.
If something is broken and needs a human touch? Not at the moment, nothing can get to the moon, let alone L2. Now give it 5 years? Then you have Starship, possibly Artimis, and could go out there yes.
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You know what that is really depressing. In all these years since 1969 we haven't had technology that can get us back to the Moon efficiently. It'd be a cosmic joke it it wasn't so depressing.
 
SLS/Orion is going to the Moon this year…though unoccupied. Starship? We will see.
Webb can be refueled..but Ariane 5’s precise performance means it won’t need fuel for a decade.

Now many asteroids said to threaten us pass no closer than 500,000 to a million miles out. So depending on where Webb is…it might get some close ups.
 
The shame is that they are killing Ariane 5.
JUICE will be its last payload…a nearly five ton probe…August 2023. That is nearly Cassini sized. Juno is to last to September 2025. JUICE won’t get to Jupiter until a decade from now, however. Europa Clipper to arrive in 2030. I was hoping for SLS to get it there before Juno burns out.

It would have been nice to have three probes there.
 
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