The JWST is in orbit

2021-12-25

in Bombs and rockets, Geek stuff, Science, Space and flight

In what may be the rocket-launched science story of the decade, the James Webb Space Telescope launched from the Guiana Space Centre in Kourou, French Guiana early Christmas morning Toronto time with me and many other science nerds watching the feed with mingled excitement and fear.

The process from here is remarkable both in terms of orbital trajectory and spacecraft deployment. This Scott Manley video shows the unusual position in space the JWST will occupy and the engineering and science reasons for it. This animation shows the planned deployment sequence for the spacecraft, which had to be folded to be housed in an aerodynamic fairing to push up through the Earth’s atmosphere.

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. December 25, 2021 at 4:10 pm

The second stage shuts down and the launch vehicle separates. The call comes out that the attitude control system is working. The solar array should be deploying automatically…. There’s a tense wait… and then the call “Sun is on the array, current is on the array!” Suddenly it’s DEAFENINGLY loud on the voice loops, with clapping and shouts of happiness echoing through the MOC. I look up to see the video feed from the launch vehicle and THERE IT IS, our beautiful observatory with its solar panel all the way out, shining in the sun.

Things keep getting better. We acquire our first ground station, Malindi in Kenya, and the MOC sends our first command to JWST, accompanied by shouts and cheering. The reaction wheels are powered up and take over. We hear “Wheel Sun!” and I write it in all caps in my log. The call comes over the voice loop: “JWST is flying on its own.”

https://blogs.nasa.gov/webb/2021/12/25/what-it-felt-like-at-mission-ops-control-when-we-launched-jwst/

. December 25, 2021 at 4:14 pm

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.

Webb is on its way to L2:

https://webb.nasa.gov/content/about/orbit.html

Our next big milestone is this evening, when we conduct the first Mid-Course Correction burn:

https://jwst.nasa.gov/content/webbLaunch/deploymentExplorer.html#5

Follow all of Webb’s upcoming milestones here:

https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html

. December 25, 2021 at 4:16 pm

The James Webb Space Telescope will not be in orbit around the Earth, like the Hubble Space Telescope is – it will actually orbit the Sun, 1.5 million kilometers (1 million miles) away from the Earth at what is called the second Lagrange point or L2. What is special about this orbit is that it lets the telescope stay in line with the Earth as it moves around the Sun. This allows the satellite’s large sunshield to protect the telescope from the light and heat of the Sun and Earth (and Moon).

https://webb.nasa.gov/content/about/orbit.html

. December 25, 2021 at 4:19 pm

The James Webb Space Telescope is launched on a direct path to an orbit around the second Sun-Earth Lagrange Point (L2), but it needs to make its own mid-course thrust correction maneuvers to get there. This is by design, because if Webb gets too much thrust from the Ariane rocket, it can’t turn around to thrust 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, Webb gets an intentional slight under-burn from the Ariane and uses its own small thrusters and on-board propellant to make up the difference.

There will be three mid-course correction (MCC) maneuvers: MCC-1a, MCC-1b, and MCC-2. The first burn, MCC-1a, is the most important and the only other time-critical operation aside from solar array deployment during Webb’s commissioning period.

https://jwst.nasa.gov/content/webbLaunch/deploymentExplorer.html

. December 26, 2021 at 10:36 am

NASA’s Webb Space Telescope Makes Time Critical Mid-Course Correction Burn

https://scitechdaily.com/nasas-webb-space-telescope-makes-time-critical-mid-course-correction-burn/

. December 26, 2021 at 11:18 am

Welcome to the JWST Exposure Time Calculator

https://jwst.etc.stsci.edu/

About Webb Orbit

https://webb.nasa.gov/content/about/orbit.html

. December 26, 2021 at 11:34 am

Once in space, Webb will need to travel about 1.5 million km from Earth to the L2 Lagrange Point beyond the Moon where it will be able to maintain a stable position without using much on-board propulsion. Along the way, and once there, some 50 deployments of the large, folded-up telescope will be necessary to prepare for scientific observations. This process will involve nearly 350 single-point failures, and if something goes wrong, it would scuttle the deployment without hope of repair. The number of single-point failures for Webb, by comparison, is a factor of three greater than the seven-minute landing of Perseverance on Mars.

https://arstechnica.com/science/2021/08/nasa-science-chief-says-its-ok-to-be-worried-or-terrified-about-webb/

. December 26, 2021 at 11:37 am

Canada’s contribution to Webb consists of two important elements, built by Honeywell with the help of scientists and engineers from the CSA, the Université de Montréal, NASA, and the Space Telescope Science Institute:

The Fine Guidance Sensor (FGS) will guide the telescope with incredible precision during all of the telescope’s observations, with an accuracy of one millionth of a degree; and

The Near-Infrared Imager and Slitless Spectrograph (NIRISS), one of the telescope’s four science instruments, will enable scientists to observe distant galaxies and study exoplanets’ atmospheres to determine their potential for supporting life.

https://www.canada.ca/en/space-agency/news/2021/12/successful-launch-of-the-most-complex-and-powerful-space-telescope.html

. December 26, 2021 at 11:45 am

Why will it take six months to see JWST’s first science images?

https://www.planetary.org/articles/jwst-first-images

. December 26, 2021 at 11:52 am

HOW ASTRONOMERS DECIDED WHERE TO POINT THE MOST POWERFUL SPACE TELESCOPE NASA EVER BUILT

https://www.theverge.com/22789561/nasa-jwst-james-webb-space-telescope-priorities-astronomy-astrophysics-exoplanets

. March 16, 2022 at 12:19 pm

NASA’s Webb Reaches Alignment Milestone, Optics Working Successfully

Following the completion of critical mirror alignment steps, NASA’s James Webb Space Telescope team expects that Webb’s optical performance will be able to meet or exceed the science goals the observatory was built to achieve.

On March 11, the Webb team completed the stage of alignment known as “fine phasing.” At this key stage in the commissioning of Webb’s Optical Telescope Element, every optical parameter that has been checked and tested is performing at, or above, expectations. The team also found no critical issues and no measurable contamination or blockages to Webb’s optical path. The observatory is able to successfully gather light from distant objects and deliver it to its instruments without issue.

https://www.nasa.gov/press-release/nasa-s-webb-reaches-alignment-milestone-optics-working-successfully

. March 16, 2022 at 10:30 pm

“You can’t help but see those thousands of galaxies behind it, really gorgeous,” said Jane Rigby, Webb operations project scientist.

Those galaxies are several billions of years old. Eventually, scientists hope Webb will see so faraway and back in time that it will only be “a couple hundred million years after the Big Bang,” she said.

The first science images won’t come until late June or early July.

The $10 billion Webb — successor to the nearly 32-year-old Hubble Space Telescope — blasted off from South America in December and reached its designated perch in January.

https://www.seattletimes.com/seattle-news/science/space-telescopes-image-of-star-gets-photobombed-by-galaxies/?amp=1

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