James Webb Space Telescope News

[the54thvoid]

Just saw the first solar wing pop out earlier than planned. Hope that's not a glitch.

 

[Space Lynx]

well I was not expecting to watch a religious sermon for this launch, but there it is... lol

bill nelson? no idea who that is... eh. glad its over. well, i missed all the good parts of the launch and tuned in during the religious sermon part, weird. well back to bed i go

this is all to hip for me, i'll just wait for the pictures in 6 months.

 

[ARF]

14 days to planned deployment:

JWSTDeployment - James Webb Space Telescope - Wikipedia
James Webb Space Telescope - Wikipedia

 

[Shrek]

Does humanity deserve to know more?

I think so; it is sobering and helps stop us make up a story of the world that is just not true.

 

[ExcuseMeWtf]

A quick rundown to bring likes of me more up to speed on that by wonderful Anton Petrov

If someone doesn't yet, I recommend his channel, he does great job as science communicator, making it fairly simple to understand for non-experts like myself.

 

[Shrek]

Still trying to understand why fuel is needed for orbiting the Lagrange point.

 

[ARF]

Still trying to understand why fuel is needed for orbiting the Lagrange point.

For changing and updating the trajectory. After all, you need a controlled movement, not free movement.

 

[TheoneandonlyMrK]

Still trying to understand why fuel is needed for orbiting the Lagrange point.

It's orbit, includes a further rotational circuit sort of vertically to the solar system , not sure why ,kinda orbiting Lagrange point , probably for communication reasons.

 

[ARF]

It's orbit, includes a further rotational circuit sort of vertically to the solar system , not sure why ,kinda orbiting Lagrange point , probably for communication reasons.

There should be some type of minimum energy required to keep its scientific mission operational. It needs to change its orientation, of course, it will be directed and focused in different directions, not at one point in space in whole its life,...

 

[Steevo]

Still trying to understand why fuel is needed for orbiting the Lagrange point.

Pressure from the sun like solar wind, solar eruptions of plasma those would be good to avoid so some fast steering/propulsion is required.

 

[authorized]

It's orbit, includes a further rotational circuit sort of vertically to the solar system , not sure why ,kinda orbiting Lagrange point , probably for communication reasons.

And Webb will orbit around L2, not sit stationary precisely at L2. Webb's orbit is represented in this screenshot from our deployment video (below), roughly to scale; it is actually similar in size to the Moon's orbit around the Earth! This orbit (which takes Webb about 6 months to complete once) keeps the telescope out of the shadows of both the Earth and Moon. Unlike Hubble, which goes in and out of Earth shadow every 90 minutes, Webb will have an unimpeded view that will allow science operations 24/7.

Orbit - NASA Science

www.jwst.nasa.gov

 

[Shrek]

Ah yes! those big heat shields would pick up a lot of light pressure.

 

[Divide Overflow]

A quick link to Goddard Space FLight Center's mission status page for the James Webb Space Telescope showing where it currently is and what stage it's at in deployment:

Where Is Webb? NASA/Webb

During Webb's launch, deployment and commissioning, 'WhereIsWebb' tracked Webb's 'flight' to L2 orbit, its state and progress during its deployment and commissioning process, and finally the release of its first images. This process is now complete. During this process, the page constantly...

www.jwst.nasa.gov

 

[Shrek]

It needs to change its orientation, of course, it will be directed and focused in different directions, not at one point in space in whole its life,...

Which reminds me of the falling cat paradox... this is a way to alter orientation without using fuel, just solar energy.

 

[Beertintedgoggles]

This quick article explains the need for fuel/thrusters at the L2 point of the Earth / Moon system but the same applies to L2 point of the Earth / Sun system which the James will be orbiting:

Ask Astro: How and why do satellites orbit Lagrange points?

Astronomy.com is for anyone who wants to learn more about astronomy events, cosmology, planets, galaxies, asteroids, astrophotography, the Big Bang, black holes, comets, constellations, eclipses, exoplanets, nebulae, meteors, quasars, observing, telescopes, NASA, Hubble, space missions...

astronomy.com

 

[Shrek]

Ah, unstable... thanks that explains it all.

 

[ARF]

Ah, unstable... thanks that explains it all.

Of course, that it is unstable. The communication satellites at 35,000 km above the Earth also use fuel for position maintenance, otherwise other forces will destabilise them to something not planned.

 

[Shrek]

Perturbations and instabilities are two different things

 

[ARF]

Perturbations and instabilities are two different things

To a great extent these two terms overlap each other:

a deviation of a system, moving object, or process from its regular or normal state or path, caused by an outside influence.
"these shifts and swings in wildlife populations are possibly related to climatic perturbations"

Perturbation - Google Search

 

[Shrek]

Not here to argue, just discuss.

The Earth's orbit is stable, and while it is perturbed by the other planets it will not be thrown out of the Solar system (there are caveats to this); but an unstable orbit will be lost without a careful balancing act. i.e., it is easy for me to stay at the bottom of a valley despite being buffered by the wind, but not so easy for me to stay at the top of a hill if buffeted.

 

[TheoneandonlyMrK]

There should be some type of minimum energy required to keep its scientific mission operational. It needs to change its orientation, of course, it will be directed and focused in different directions, not at one point in space in whole its life,...

Yeah but also, it's not stationary at Lagrange point it orbits Lagrange point by quite a margin above and below the solar systems rotational axis so orbiting two points simultaneously and Accurately , probably to maintain sunlight on its panels and to stop the earth obstructing the sun's light.

I quote
"Webb will orbit around L2, not sit stationary precisely at L2. Webb's orbit is represented in this screenshot from our deployment video (below), roughly to scale; it is actually similar in size to the Moon's orbit around the Earth! This orbit (which takes Webb about 6 months to complete once) keeps the telescope out of the shadows of both the Earth and Moon. Unlike Hubble, which goes in and out of Earth shadow every 90 minutes, Webb will have an unimpeded view that will allow science operations 24/7."

From @authorized s link.

 

[Divide Overflow]

It needs to change its orientation, of course, it will be directed and focused in different directions, not at one point in space in whole its life

The JWST has six reaction control wheels which are responsible for keeping the telescope pointed in the desired direction. It's limited fuel supply is used for mid course correction burns and station keeping once it is in L2 orbit. This fuel supply will last for approximately 10 years.

From NASA:
"Webb continues in coast phase, and is now oriented correctly with respect to the Sun. The six reaction wheels of the spacecraft’s attitude control system have been powered on, and they are now responsible for keeping the spacecraft pointing in the right direction – so that its massive sunshield, which is the size of a tennis court and which will deploy over the course of the next week – will be able to keep the telescope protected from solar radiation and heat."

UPDATE:
At 7:50 pm EST, Webb’s first mid-course correction burn began. It lasted 65 minutes and is now complete. This burn is one of two milestones that are time critical — the first was the solar array deployment, which happened shortly after launch.

This burn adjusts Webb’s trajectory toward the second Lagrange point, commonly known as L2. After launch, Webb needs to make its own mid-course thrust correction maneuvers to get to its orbit. This is by design: Webb received an intentional slight under-burn from the Ariane-5 that launched it into space, because it’s not possible to correct for overthrust. If Webb gets too much thrust, it can’t turn around to move back toward Earth because that would directly expose its telescope optics and structure to the Sun, overheating them and aborting the science mission before it can even begin.

Therefore, we ease up to the correct velocity in three stages, being careful never to deliver too much thrust — there will be three mid-course correction maneuvers in total.

After this burn, no key milestones are time critical, so the order, location, timing, and duration of deployments may change.

 

[delshay]

For those interested, not sure if it's important but here's a LIVE tracker

LIVE! James Webb Telescope Tracker #NASA #WEBB - YouTube

 

[the54thvoid]

This is the direct link to the JWST deployment page from NASA.

Deployment Explorer Webb/NASA

Interactively explore Webb's deployments on this page. Webb is NASA's largest and most powerful space science telescope ever constructed. Webb’s enormous size and frigid operating temperature present extraordinary engineering challenges. After launching from French Guiana, the observatory will...

www.jwst.nasa.gov

 

[ARF]

James Webb Space Telescope notches crucial maneuver to set its path | Space

According to NASA, this burn, dubbed Mid-Course Correction Burn 1a or MCC1a, was the most important of the three burns the spacecraft will make during its journey to L2, and the only one that needed to be particularly carefully timed.

A spacecraft often needs to conduct a trajectory maneuver in the hours after launch to account for slight differences in where its rocket deposits the machinery, however, this burn for Webb included a crucial constraint, according to NASA: The spacecraft can't slow itself down because doing so would require turning around, exposing its super-heat-sensitive instruments to the Sun.

Instead, the observatory can only increase its speed, so the observatory's launch sequence was designed to err on the side of the Ariane 5 rocket providing just a little less power than required, rather than just a little more. The MCC1a burn was the observatory's opportunity to finetune its trajectory toward L2.

Does this mean that the JWST will never look at the direction of the Universe towards the Sun?
That would significantly limit its scientific mission.

It basically means that it would wait for the Earth to pass to that position on its orbit around the Sun exposing its availability to look at that part of the space.

Well, I think we need at least one more JWST sent to the opposite position on the Earth's orbit