Okay, then explain this. You have seemed to mention a few times that Earth and Webb will be traveling at the same orbit velocity. Webb will just be in a location the earth has not reached yet.
That doesn't seem to be right.
Moderator: Animal
Okay, then explain this. You have seemed to mention a few times that Earth and Webb will be traveling at the same orbit velocity. Webb will just be in a location the earth has not reached yet.
another (boring) speed update. Right now its at 0.3438 mi/sec. Meaning it has slowed another 0.03 mi/sec. I read a scientist guy describe it as if it is coasting slightly uphill.Animal wrote: ↑Sun Jan 02, 2022 4:38 pmSpeed update. Okay, its been around 24 hours and the speed has reduced to 0.3740 mi/second. It is showing to be 22 days away from its final position.Animal wrote: ↑Sun Jan 02, 2022 12:11 am It got 1/2 way to its final orbit in 7 days. but it looks like it will be around day 30 when it reaches the target location. I guess that means it is gradually slowing down as it goes?
Right now its speed is 0.3961 mi/sec. I'll check that in a day or two and see how it compares.
If it loses .02 mi/sec each day, that would mean it would lose .44 mi/sec in speed over the next 22 days, which would bring it to a stop. So, maybe that is what it is doing. Maybe its speed is set to gradually be decelerating until it stops at exactly the right location.
Lagrange math (knock yourself out)
Yes. I understand that. Webb will be at point L2. Which means it is about 1.5 million kilometers away from earth (and the sun). It will remain in that respective position to earth as it rotates the sun, meaning it will have to be moving faster than earth since its orbital path is larger than earth's. And the earth will never be any any of the locations of Webb since the earth is closer to the sun than Webb.Antknot wrote: ↑Mon Jan 03, 2022 5:38 pmLagrange math (knock yourself out)
https://www.khanacademy.org/math/multiv ... s-examples
Lagrange points
https://en.m.wikipedia.org/wiki/Lagrange_point
You don't understand.Animal wrote: ↑Mon Jan 03, 2022 5:55 pmYes. I understand that. Webb will be at point L2. Which means it is about 1.5 million kilometers away from earth (and the sun). It will remain in that respective position to earth as it rotates the sun, meaning it will have to be moving faster than earth since its orbital path is larger than earth's. And the earth will never be any any of the locations of Webb since the earth is closer to the sun than Webb.Antknot wrote: ↑Mon Jan 03, 2022 5:38 pmLagrange math (knock yourself out)
https://www.khanacademy.org/math/multiv ... s-examples
Lagrange points
https://en.m.wikipedia.org/wiki/Lagrange_point
Now, explain what you mean when you say they have the same "orbital velocity" and that Webb will be in a location that the earth has not reached yet.
Ok. I thought that's what you have been saying. which is wrong. webb will be 1.5 million kilometers further from the sun than earth.Antknot wrote: ↑Mon Jan 03, 2022 7:08 pmYou don't understand.Animal wrote: ↑Mon Jan 03, 2022 5:55 pmYes. I understand that. Webb will be at point L2. Which means it is about 1.5 million kilometers away from earth (and the sun). It will remain in that respective position to earth as it rotates the sun, meaning it will have to be moving faster than earth since its orbital path is larger than earth's. And the earth will never be any any of the locations of Webb since the earth is closer to the sun than Webb.Antknot wrote: ↑Mon Jan 03, 2022 5:38 pmLagrange math (knock yourself out)
https://www.khanacademy.org/math/multiv ... s-examples
Lagrange points
https://en.m.wikipedia.org/wiki/Lagrange_point
Now, explain what you mean when you say they have the same "orbital velocity" and that Webb will be in a location that the earth has not reached yet.
Webb will be in the same orbital path as Earth roughly 93 million miles from the Sun. It will be moving throuh space at the same rate as Earth. It will be located 1.5 million miles from Earth (Earth's orbit is an ellipse not a circle thus approx numbers)
Think of a single lane race track. Webb and Earth will be running laps on that race track. They will be running at the same speed. Webb will be ahead of Earth.
Great question and great answer.Animal wrote: ↑Fri Jan 07, 2022 3:47 pm You may find yourself asking....
"Why aren't there camera's on Webb so we can watch these critical deployments as the telescope unfolds?"
"Adding cameras to watch an unprecedently complicated deployment of such a precious spacecraft as Webb sounds like a no-brainer, but in Webb’s case, there’s much more to it than meets the eye,” said Paul Geithner, deputy project manager – technical for the Webb telescope at NASA’s Goddard Space Flight Center. “It’s not as straightforward as adding a doorbell cam or even a rocket cam.”
First of all, Webb is big, undergoes many configuration changes during deployment, and has many specific locations of import to deployment. Monitoring Webb’s deployments with cameras would require either multiple narrow-field cameras, adding significant complexity, or a few wide-field cameras that would yield little in the way of helpful detailed information. Wiring harnesses for cameras would have to cross moving interfaces around the observatory and add more risk of vibrations and heat leaking through, presenting a particular challenge for cameras located on the cold side of Webb.
Then there’s the issue of lighting. Webb is very shiny, so visible cameras on the Sun-facing side would be subject to extreme glare and contrast issues, while ones on the cold, shaded side would need added lighting. Although infrared or thermal-imaging cameras on the cold side could obviate the need for illumination, they would still present the same harnessing disadvantages. Furthermore, cameras on the cold side would have to work at very cold cryogenic temperatures. This would either require ‘ordinary’ cameras to be encapsulated or insulated so they would work in extreme cold, or development of special-purpose cryogenic-compatible cameras just for deployment surveillance.
Notwithstanding these challenges, engineers mocked up and tested some camera schemes on full-scale mockups of Webb hardware. However, they found that deployment surveillance cameras would not add significant information of value for engineering teams commanding the spacecraft from the ground.
“Webb’s built-in sense of ‘touch’ (for example, switches and various mechanical, electrical, and temperature sensors) provides much more useful information than mere surveillance cameras can,” said Geithner. “We instrumented Webb like we do many other one-of-a-kind spacecraft, to provide all the specific information necessary to inform engineers on Earth about the observatory’s health and status during all activities.” Engineers can also correlate years of data from ground testing with telemetry data from flight sensors to insightfully interpret and understand flight sensor data.