NASA Webb Telescope Structure is Sound After Vibration Testing Detects Anomaly

The 18-segment gold coated primary mirror of NASA’s James Webb Space Telescope is raised into vertical alignment in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on Nov. 2, 2016. The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com

NASA GODDARD SPACE FLIGHT CENTER, MD – The James Webb Space Telescope (JWST) is now deemed “sound” and apparently unscathed, engineers have concluded, based on results from a new batch of intensive inspections of the observatory’s structure, after concerns were raised in early December when technicians initially detected “anomalous readings” during a preplanned series of vibration tests, NASA announced Dec. 23.

After conducting both “visual and ultrasonic examinations” at NASA’s Goddard Space Flight Center in Maryland, engineers have found it to be safe at this point with “no visible signs of damage.”

But because so much is on the line with NASA’s $8.8 Billion groundbreaking Webb telescope mission that will peer back to nearly the dawn of time, engineers are still investigating the “root cause” of the “vibration anomaly” first detected amidst shake testing on Dec. 3.

“The team is making good progress at identifying the root cause of the vibration anomaly,” NASA explained in a Dec 23 statement – much to everyone’s relief!

“They have successfully conducted two low level vibrations of the telescope.”

“All visual and ultrasonic examinations of the structure continue to show it to be sound.”

Technicians work on the James Webb Space Telescope in the massive clean room at NASA’s Goddard Space Flight Center, Greenbelt, Maryland, on Nov. 2, 2016, as the completed golden primary mirror and observatory structure stands gloriously vertical on a work stand, reflecting incoming light from the area and observation deck. Credit: Ken Kremer/kenkremer.com

Starting late November, technicians began a defined series of environmental tests including vibration and acoustics tests to make sure that the telescopes huge optical structure was fit for blastoff and could safely withstand the powerful shaking encountered during a rocket launch and the especially harsh rigors of the space environment. It would be useless otherwise – unable to carry out unparallelled science.

To carry out the vibration and acoustics tests conducted on equipment located in a shirtsleeve environment, the telescope structure was first carefully placed inside a ‘clean tent’ structure to protect it from dirt and grime and maintain the pristine clean room conditions available inside Goddard’s massive clean room – where it has been undergoing assembly for the past year.

NASA’s James Webb Space Telescope placed inside a “clean tent” in Nov. 2016 to protect it from dust and dirt as engineers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland transport it out of the relatively dust-free cleanroom and into a shirtsleeve environment to conduct vibration and acoustics tests to confirm it is fit for launch in 2018. Credit: NASA/Chris Gunn

NASA’s James Webb Space Telescope is the most powerful space telescope ever built and is the scientific successor to the phenomenally successful Hubble Space Telescope (HST).

The mammoth 6.5 meter diameter primary mirror has enough light gathering capability to scan back over 13.5 billion years and see the formation of the first stars and galaxies in the early universe.

The Webb telescope will launch on an ESA Ariane V booster from the Guiana Space Center in Kourou, French Guiana in 2018.

“The James Webb Space Telescope is undergoing testing to make sure the spacecraft withstands the harsh conditions of launch, and to find and remedy all possible concerns before it is launched from French Guiana in 2018.”

However, shortly after the vibration testing began technicians soon discovered unexpected “anomalous readings” during a shake test of the telescope on Dec. 3, as the agency initially announced in a status update on the JWST website.

The anomalous readings were found during one of the vibration tests in progress on the shaker table, via accelerometers attached to the observatories optical structure known as OTIS.

“During the vibration testing on December 3, at Goddard Space Flight Center in Greenbelt, Maryland, accelerometers attached to the telescope detected anomalous readings during a particular test,” the team elaborated.

So the team quickly conducted further “low level vibration” tests and inspections to more fully understand the nature of the anomaly, as well as scrutinize the accelerometer data for clues.

“Further tests to identify the source of the anomaly are underway. The engineering team investigating the vibe anomaly has made numerous detailed visual inspections of the Webb telescope and has found no visible signs of damage.”

“They are continuing their analysis of accelerometer data to better determine the source of the anomaly.”

The team is measuring and recording the responses of the structure to the fresh low level vibration tests and will compare these new data to results obtained prior to detection of the anomaly.

Work continues over the holidays to ensure Webb is safe and sound and can meet its 2018 launch target. After thoroughly reviewing all the data the team hope to restart the planned vibration and acoustic testing in the new year.

“Currently, the team is continuing their analyses with the goal of having a review of their findings, conclusions and plans for resuming vibration testing in January.”

Webb’s massive optical structure being tested is known as OTIS or Optical Telescope element and Integrated Science. It includes the fully assembled 18-segment gold coated primary mirror and the science instrument module housing the four science instruments

OTIS is a combination of the OTE (Optical Telescope Assembly) and the ISIM (Integrated Science Instrument Module) together.

“OTIS is essentially the entire optical train of the observatory!” said John Durning, Webb Telescope Deputy Project Manager, in an earlier exclusive interview with Universe Today at NASA’s Goddard Space Flight Center.

“It’s the critical photon path for the system.”

The components were fully integrated this past summer at Goddard.

The combined OTIS entity of mirrors, science module and backplane truss weighs 8786 lbs (3940 kg) and measures 28’3” (8.6m) x 8”5” (2.6 m) x 7”10“ (2.4 m).

The environmental testing is being done at Goddard before shipping the huge structure to NASA’s Johnson Space Center in February 2017 for further ultra low temperature testing in the cryovac thermal vacuum chamber.

The 6.5 meter diameter ‘golden’ primary mirror is comprised of 18 hexagonal segments – looking honeycomb-like in appearance.

And it’s just mesmerizing to gaze at – as I had the opportunity to do on a few occasions at Goddard this past year – standing vertically in November and seated horizontally in May.

Each of the 18 hexagonal-shaped primary mirror segments measures just over 4.2 feet (1.3 meters) across and weighs approximately 88 pounds (40 kilograms). They are made of beryllium, gold coated and about the size of a coffee table.

All 18 gold coated primary mirrors of NASA’s James Webb Space Telescope are seen fully unveiled after removal of protective covers installed onto the backplane structure, as technicians work inside the massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016. The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com

The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Webb is designed to look at the first light of the Universe and will be able to peer back in time to when the first stars and first galaxies were forming.

It will also study the history of our universe and the formation of our solar system as well as other solar systems and exoplanets, some of which may be capable of supporting life on planets similar to Earth.

Up close side-view of newly exposed gold coated primary mirrors installed onto mirror backplane holding structure of NASA’s James Webb Space Telescope inside the massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016. Aft optics subsystem stands upright at center of 18 mirror segments between stowed secondary mirror mount booms. Credit: Ken Kremer/kenkremer.com

Watch this space for my ongoing reports on JWST mirrors, science, construction and testing.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

Ken Kremer/Universe Today reflecting in and about the golden mirrors of NASA’s James Webb Space Telescope which will peer back 13.5 Billion years to unravel the mysteries off the formation of the early Universe and tell us how our place in the Universe came to be. Credit: Ken Kremer/kenkremer.com

Webb Telescope Gets its Science Instruments Installed

In this rare view, the James Webb Space Telescope team crane lifted the science instrument package for installation into the telescope structure.  Credits: NASA/Chris Gunn
In this rare view, the James Webb Space Telescope team crane lifted the science instrument package for installation into the telescope structure. Credits: NASA/Chris Gunn

The package of powerful science instruments at the heart of NASA’s mammoth James Webb Space Telescope (JWST) have been successfully installed into the telescopes structure.

A team of two dozen engineers and technicians working with “surgical precision” inside the world’s largest clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, meticulously guided the instrument package known as the ISIM (Integrated Science Instrument Module) into the telescope truss structure.

ISIM is located right behind the 6.5 meter diameter golden primary mirror – as seen in NASA’s and my photos herein.

The ISIM holds the observatory’s international quartet of state-of-the-art research instruments, funded, built and provided by research teams in the US, Canada and Europe.

“This is a tremendous accomplishment for our worldwide team,” said John Mather, James Webb Space Telescope Project Scientist and Nobel Laureate, in a statement.

“There are vital instruments in this package from Europe and Canada as well as the US and we are so proud that everything is working so beautifully, 20 years after we started designing our observatory.”

This side shot shows a glimpse inside a massive clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland where the James Webb Space Telescope team worked meticulously to complete the science instrument package installation.  Credits: NASA/Desiree Stover
This side shot shows a glimpse inside a massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland where the James Webb Space Telescope team worked meticulously to complete the science instrument package installation. Credits: NASA/Desiree Stover

Just as with the mirrors installation and other assembly tasks, the technicians practiced the crucial ISIM installation procedure numerous times via test runs, computer modeling and a mock-up of the instrument package.

To accomplish the ISIM installation, the telescope structure had to be flipped over and placed into the giant work gantry in the clean room to enable access by the technicians.

“The telescope structure has to be turned over and put into the gantry system [in the clean room],” said John Durning, Webb Telescope Deputy Project Manager, in an exclusive interview with Universe Today at NASA’s Goddard Space Flight Center.

“Then we take ISIM and install in the back of the telescope.”

The team used an overhead crane to lift and maneuver the heavy ISIM science instrument package in the clean room. Then they lowered it into the enclosure behind the mirrors on the telescopes backside and secured it to the structure.

“Our personnel were navigating a very tight space with very valuable hardware,” said Jamie Dunn, ISIM Manager.

“We needed the room to be quiet so if someone said something we would be able to hear them. You listen not only for what other people say, but to hear if something doesn’t sound right.”

Up close view shows cone shaped Aft Optics Subsystem (AOS) standing at center of Webb telescopes 18 segment primary mirror at NASA's Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016.  ISIM science instrument module will be installed inside truss structure below.  Credit: Ken Kremer/kenkremer.com
Up close view shows cone shaped Aft Optics Subsystem (AOS) standing at center of Webb telescopes 18 segment primary mirror at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016. ISIM science instrument module will be installed inside truss structure below. Credit: Ken Kremer/kenkremer.com

The ISIM installation continues the excellently executed final assembly phase of Webb at Goddard this year. And comes just weeks after workers finished installing the entire mirror system.

This author has witnessed and reported on the assembly progress at Goddard on numerous occasions, including after the mirrors were recently uncovered and unveiled in all their golden glory.

“The entire mirror system is checked out. The system has been integrated and the alignment has been checked,” said John Durning, Webb Telescope Deputy Project Manager, in an exclusive interview with Universe Today at NASA’s Goddard Space Flight Center.

Up close side-view of newly exposed gold coated primary mirrors installed onto mirror backplane holding structure of  NASA’s James Webb Space Telescope inside the massive clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016.   Aft optics subsystem stands upright at center of 18 mirror segments between stowed secondary mirror mount booms.  Credit: Ken Kremer/kenkremer.com
Up close side-view of newly exposed gold coated primary mirrors installed onto mirror backplane holding structure of NASA’s James Webb Space Telescope inside the massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016. Aft optics subsystem stands upright at center of 18 mirror segments between stowed secondary mirror mount booms. Credit: Ken Kremer/kenkremer.com

ISIM is a collection of cameras and spectrographs that will record the light collected by Webb’s giant golden primary mirror.

“It will take us a few months to install ISIM and align it and make sure everything is where it needs to be,” Durning told me.

The primary mirror is comprised of 18 hexagonal segments.

Each of the 18 hexagonal-shaped primary mirror segments measures just over 4.2 feet (1.3 meters) across and weighs approximately 88 pounds (40 kilograms). They are made of beryllium, gold coated and about the size of a coffee table.

Webb’s golden mirror structure was tilted up for a very brief period on May 4 as seen in this NASA time-lapse video:

The 18-segment primary mirror of NASA’s James Webb Space Telescope was raised into vertical alignment in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on May 4, 2016. Credit: NASA

The gargantuan observatory will significantly exceed the light gathering power of NASA’s Hubble Space Telescope (HST) – currently the most powerful space telescope ever sent to space.

With the mirror structure complete, the next step was the ISIM science module installation.

To accomplish that installation, technicians carefully moved the Webb mirror structure into the clean room gantry structure.

As shown in this time-lapse video we created from Webbcam images, they tilted the structure vertically, flipped it around, lowered it back down horizontally and then transported it via an overhead crane into the work platform.

Time-lapse showing the uncovered 18-segment primary mirror of NASA’s James Webb Space Telescope being raised into vertical position, flipped and lowered upside down to horizontal position and then moved to processing gantry in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on May 4/5, 2016. Images: NASA Webbcam. Time-lapse by Ken Kremer/kenkremer.com/Alex Polimeni

The telescope will launch on an Ariane V booster from the Guiana Space Center in Kourou, French Guiana in 2018.

The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Webb is designed to look at the first light of the Universe and will be able to peer back in time to when the first stars and first galaxies were forming. It will also study the history of our universe and the formation of our solar system as well as other solar systems and exoplanets, some of which may be capable of supporting life on planets similar to Earth.

All 18 gold coated primary mirrors of NASA’s James Webb Space Telescope are seen fully unveiled after removal of protective covers installed onto the backplane structure, as technicians work inside the massive clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016.  The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com
All 18 gold coated primary mirrors of NASA’s James Webb Space Telescope are seen fully unveiled after removal of protective covers installed onto the backplane structure, as technicians work inside the massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016. The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com

More about ISIM and upcoming testing in the next story.

Watch this space for my ongoing reports on JWST mirrors, science, construction and testing.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

James Webb Space Telescope Mirror Installation Reaches Halfway Point

As history closes in on 2015, assembly of NASA’s James Webb Space Telescope (JWST) reached a historic milestone as the installation of the primary mirrors onto the telescope structure reached the halfway point to completion and marks the final assembly phase of the colossal observatory.

Technicians have just installed the ninth of 18 primary flight mirrors onto the mirror holding backplane structure at the agency’s Goddard Space Flight Center in Greenbelt, Maryland. Continue reading “James Webb Space Telescope Mirror Installation Reaches Halfway Point”

NASA Webb Telescope Construction Leaps Forward with Delivery of Mirror Holding Backbone Flight Structure

View showing actual flight structure of mirror backplane unit for NASA’s James Webb Space Telescope (JWST) that holds 18 segment primary mirror array and secondary mirror mount at front, in stowed-for-launch configuration. JWST is being assembled here by technicians inside the world’s largest cleanroom at NASA Goddard Space Flight Center, Greenbelt, Md. Credit: Ken Kremer/kenkremer.com
Story/imagery updated[/caption]

NASA GODDARD SPACE FLIGHT CENTER, MD – The construction pace for NASA’s James Webb Space Telescope (JWST) took a major leap forward with delivery of the actual flight structure that serves as the observatory’s critical mirror holding backbone – to NASA’s Goddard Space Flight Center in Greenbelt, Maryland and observed by Universe Today.

“We are in good shape with the James Webb Space Telescope,” said Dr. John Mather, NASA’s Nobel Prize Winning scientist, in an exclusive interview with Universe Today at NASA Goddard during a visit to the flight structure – shown in my photos herein. Note: Read an Italian language version of this story – here at Alive Universe

And the mammoth $8.6 Billion Webb telescope has mammoth scientific objectives as the scientific successor to NASA’s Hubble Space Telescope (HST) – now celebrating its 25th anniversary in Earth orbit.

“JWST has the capability to look back towards the very first objects that formed after the Big Bang,” Mather told Universe Today.

How is that possible?

“James Webb has a much bigger mirror than Hubble. So its resolution is much better,” said astronaut and NASA science chief John Grunsfeld, during an exclusive interview at NASA Goddard. Grunsfeld flew on a trio of Hubble servicing missions aboard the Space Shuttle, including the final one during STS-125 in 2009.

“JWST can look back further in time, and a greater distance than Hubble, so we can see those first stars and galaxies formed in the Universe.”

These discoveries are only possible with Webb, which will become the most powerful telescope ever sent to space when it launches in 2018.

Up close view of actual side wing backplane of NASA's James Webb Space Telescope (JWST) that will hold 3 of the observatory’s 18 primary mirrors, as technicians work inside cleanroom at NASA Goddard Space Flight Center, Greenbelt, Md.  Credit: Ken Kremer/kenkremer.com
Up close view of actual side wing backplane of NASA’s James Webb Space Telescope (JWST) that will hold 3 of the observatory’s 18 primary mirrors, as technicians work inside cleanroom at NASA Goddard Space Flight Center, Greenbelt, Md. Credit: Ken Kremer/kenkremer.com

The massive JWST flight structure unit includes the “backplane assembly” that clasps in place all of the telescopes primary and secondary mirrors, as well as its ISIM science module loaded with the observatory’s quartet of state-of-the-art research instruments.

“The backplane looks really great,” Grunsfeld told me.

Numerous NASA centers and aerospace companies are involved in building the observatory and its backplane structure holding the mirrors that will search back some 13.4 billion years.

“The backplane structure just arrived in late August from Northrop Grumman Aerospace Systems in Redondo Beach, California,” said Sandra Irish, JWST lead structural engineer during an interview with Universe Today at the NASA Goddard cleanroom facility.

“This is the actual flight hardware.”

Side view of flight unit mirror backplane assembly structure for NASA's James Webb Space Telescope (JWST) that holds primary mirror array and secondary mirror mount in stowed-for-launch configuration.  JWST is being assembled technicians inside the world’s largest cleanroom at NASA Goddard Space Flight Center, Greenbelt, Md.  Credit: Ken Kremer/kenkremer.com
Side view of flight unit mirror backplane assembly structure for NASA’s James Webb Space Telescope (JWST) that holds primary mirror array and secondary mirror mount in stowed-for-launch configuration. JWST is being assembled technicians inside the cleanroom at NASA Goddard Space Flight Center, Greenbelt, Md. Credit: Ken Kremer/kenkremer.com

The purpose of JWST’s backplane assembly is to hold the telescopes 18 segment, 21-foot (6.5-meter) diameter primary mirror nearly motionless while floating in the utterly frigid space environment, thereby enabling the observatory to peer out into deep space for precise science gathering measurements never before possible.

The massive telescope structure “includes the primary mirror backplane assembly; the main backplane support fixture; and the deployable tower structure that lifts the telescope off of the spacecraft. The three arms at the top come together into a ring where the secondary mirror will reside,” say officials.

The backplane traveled a long and winding road before arriving at Goddard.

“The backplane structure was designed and built at Orbital ATK with NASA oversight,” Irish explained. The assembly work was done at the firms facilities in Magna, Utah.

“Then it was sent to Northrop Grumman in Redondo Beach, California for static testing. Then it came here to Goddard. Orbital ATK also built the composite tubes for the ISIM science module structure.”

The observatory’s complete flight structure measures about 26 feet (nearly 8 meters) from its base to the tip of the tripod arms and mirror mount holding the round secondary mirror.

Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom.  Credit: NASA/ESA
Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom. Credit: NASA/ESA

The flight structure and backplane assembly arrived at Goddard in its stowed-for-launch configuration after being flown cross country from California.

“It is here for the installation of all the mirrors to build up the entire telescope assembly here at Goddard. It will be fully tested here before it is delivered to the Johnson Space Center in Houston and then back to California,” Irish elaborated.

The overall assembly is currently attached to a pair of large yellow and white fixtures that firmly secure the flight unit, to stand it upright and rotate as needed, as it undergoes acceptance testing by engineers and technicians before commencement of the next big step – the crucial mirror installation that starts soon inside the world’s largest cleanroom at NASA Goddard.

Overhead cranes are also used to maneuver the observatory structure as engineers inspect and test the unit.

But several weeks of preparatory work are in progress before the painstakingly precise mirror installation can begin under the most pristine cleanroom operating conditions.

“Right now the technicians are installing harnesses that we need to mount all over the structure,” Irish told me.

“These harnesses will go to our electronic systems and the mirrors in order to monitor their actuation on orbit. So that’s done first.”

What is the construction sequence at Goddard for the installation of the mirrors and science instruments and what comes next?

“This fall we will be installing every mirror, starting around late October/early November. Then next April 2016 we will install the ISIM science module inside the backplane structure.”

“The ISIM mounts all four of the telescope science instrument. So the mirrors go on first, then the ISIM gets installed and then it will really be the telescope structure.” ISIM carries some 7,500 pounds (2400 kg) of telescope optics and instruments.

“Then starting about next July/August 2016 we start the environmental testing.”

The actual flight mirror backplane is comprised of three segments – the main central segment and a pair of outer wing-like parts holding three mirrors each. They will be unfolded from the stowed-for-launch configuration to the “deployed” configuration to carry out the mirror installation. Then be folded back over into launch configuration for eventual placement inside the payload fairing of the Ariane V ECA booster rocket.

The telescope will launch from the Guiana Space Center in Kourou, French Guiana in 2018.

Gold coated flight spare of a JWST primary mirror segment made of beryllium and used for test operations inside the NASA Goddard clean room.  Credit: Ken Kremer- kenkremer.com
Gold coated flight spare of a JWST primary mirror segment made of beryllium and used for test operations inside the NASA Goddard clean room. Credit: Ken Kremer- kenkremer.com

The telescopes primary and secondary flight mirrors have already arrived at Goddard.

The mirrors must remained precisely aligned and nearly motionless in order for JWST to successfully carry out science investigations. While operating at extraordinarily cold temperatures between -406 and -343 degrees Fahrenheit the backplane must not move more than 38 nanometers, approximately 1/1,000 the diameter of a human hair.

To account for the tiniest of errors and enhance science, each of the primary mirrors is equipped with actuators for minute adjustments.

“A beautiful advantage of Webb that’s different from Hubble is the fact that we do have actuation [capability] of every single one of our mirrors. So if we are off by just a little bit on either our calculations or from misalignment from launch or the zero gravity release, we can do some fine adjustments on orbit.”

“We can adjust every mirror within 50 nanometers.”

“That’s important because we can’t send astronauts to fix our telescope. We just can’t.”

“The telescope is a million miles away.”

NASA’s team at Goddard has already practiced mirror installation because there are no second chances.

“We only have one shot to get this right!” Irish emphasized.

Watch for more on the mirror installation in my upcoming story.

JWST is the successor to the 25 year old Hubble Space Telescope and will become the most powerful telescope ever sent to space.

Webb is designed to look at the first light of the Universe and will be able to peer back in time to when the first stars and first galaxies were forming.

The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

NASA has overall responsibility and Northrop Grumman is the prime contractor for JWST.

“The telescope is on schedule for its launch in 2018 in October,” Mather told me.

And the payoff from JWST will be monumental!

“On everything from nearby planets to the most distant universe, James Webb will transform our view of the Universe,” Grunsfeld beams.

Watch for more on JWST construction and mirror installation in part 2 soon.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

A comparison of the primary mirror used by Hubble and the primary mirror array used by the James Webb Space Telescope. Photo Credit: NASA
A comparison of the primary mirror used by Hubble and the primary mirror array used by the James Webb Space Telescope. Photo Credit: NASA
NASA Science chief and astronaut John Grunsfeld discusses James Webb Space Telescope project at NASA Goddard Space Flight Center in Maryland.  Credit: Ken Kremer/kenkremer.com
NASA Science chief and astronaut John Grunsfeld discusses James Webb Space Telescope project at NASA Goddard Space Flight Center in Maryland. Credit: Ken Kremer/kenkremer.com