Posted on 01/22/2022 9:04:46 PM PST by zeestephen
On Monday, January 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.
(Excerpt) Read more at scitechdaily.com ...
JWST’s current radial velocity away from Earth is just 468 mph, with 20900 miles to go. It loses a few dozen mph per day at this point; Earth’s gravitation pull is about one-millionth what it was when it was launched.
Where is Webb?
https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html
Getting crowded at old L2. Two satellites already parked there.
Funny, thought getting those two up there would have been a big deal, not heard of it until Webb was on the way.
I do not understand the ‘a’ ‘b’ and ‘c’ ‘d’ temperatures...
These are sensors on different parts of the spacecraft. If you hover over them it will tell you where they are.
Thanks!
(had to go to a secondary browser to be able to see that)
I’ve been checking it’s progress at least a dozen times a day, I can’t wait to see its first successful pictures.
I do not know what the orbital insertion speed is. I assume the final burn adds speed to the current 468 mph.
Webb will do one revolution around L-2 every six months. Webb's distance from L-2 is roughly the same as the distance between Earth and Moon.
I recently read that docking and maintaining Webb precisely at L-2 would require significantly more fuel than the L-2 orbit does.
Also, being anchored at L-2 creates Earth and Moon shadow issues for Webb, which would impact the available energy, plus, cause fluctuating temperature issues with vital equipment.
Webb will not park. It will orbit L-2. Orbiting requires less fuel expenditure and also avoids Earth and Moon shadow issues.
It seems likely that the first two satellites also orbit, but I do not know that for certain.
Both of the cold side temperature points will drift down to minus 388 F over the next few months.
The cold side actually has heaters that prevent a rapid temperature decline, for two reasons.
First, a rapid decline might damage some of the equipment.
Second, residual Earth moisture might turn to ice, instead of just sublimating away as water vapor over time.
One million miles is nothing in space.
Considering a light year is close to 6 trillion miles.
When it comes to stars, all that we see is a dot.
Build a bigger telescope, you can see a bigger dot...
It’s a great big universe
And we’re all really puny
We’re just tiny little specks
About the size of Mickey Rooney
Re: A bigger dot
Any celestial body that has heat radiates light.
The entire spectrum of light - from radio waves to gamma waves - carries a vast amount of information about age, distance, speed, energy source, elements, state of matter, gravity, etc.
It is just basic science at the moment, little or no utility at the moment, but learning things about a universe we cannot currently visit is a good thing, and can ultimately benefit mankind more than it harms us.
What is Webb’s energy source if it’s hidden from the sun?
Part of it sees the sun, most of it is shielded from the sun.
It has solar cells that are located on its sunny side; they provide its power.
that makes sense
List Of Objects At Lagrange Points
L2
L2 is the Lagrange point located approximately 1.5 million kilometers from Earth in the direction opposite the Sun. Spacecraft at the Sun–Earth L2 point are in a Lissajous orbit until decommissioned, when they are sent into a heliocentric graveyard orbit.[citation needed]
Past probes
Animation of Wilkinson Microwave Anisotropy Probe's trajectory from 1 July 2001 to 7 April 2009
WMAP · Earth2001 – 2010: NASA's Wilkinson Microwave Anisotropy Probe (WMAP)[6] observed the cosmic microwave background. It was moved to a heliocentric orbit to avoid posing a hazard to future missions.
2003 – 2004: NASA's WIND. The spacecraft then went to Earth orbit, before heading to L1.[7]
2009 – 2013:[8] The ESA Herschel Space Observatory exhausted its supply of liquid helium and was moved from the Lagrangian point in June 2013.
2009 – 2013: At the end of its mission ESA's Planck spacecraft was put into a heliocentric orbit and passivated to prevent it from endangering any future missions.
2011 – 2012: CNSA's Chang'e 2.[9][10] Chang'e 2 was then placed onto a heliocentric orbit that took it past the near-Earth asteroid 4179 Toutatis.
Present probes
The ESA Gaia probe
The joint Russian-German high-energy astrophysics observatory Spektr-RG
The joint NASA, ESA and CSA James Webb Space Telescope (JWST) (arriving late January 2022)
Planned probes
The ESA Euclid mission, to better understand dark energy and dark matter by accurately measuring the acceleration of the universe.
The NASA Nancy Grace Roman Space Telescope (WFIRST) The ESA PLATO mission, which will find and characterize rocky exoplanets.
The JAXA LiteBIRD mission.
The ESA ARIEL mission, which will observe the atmospheres of exoplanets.
The joint ESA-JAXA Comet Interceptor
The NASA Advanced Technology Large-Aperture Space
Telescope, which would replace the Hubble Space Telescope.
Cancelled probes
The ESA Eddington mission
The NASA Terrestrial Planet Finder mission (may be placed in an Earth-trailing orbit instead)
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