This rare overhead shot of the James Webb Space Telescope shows the nine primary flight mirrors installed on the telescope structure in a clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Credits: NASA's Goddard Space Flight Center/Chris Gunn
The James Webb Space Telescope team successfully installed the first flight mirror onto the telescope structure at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Credits: NASA/Chris Gunn
The James Webb Space Telescope team successfully installed the first flight mirror onto the telescope structure at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Credits: NASA/Chris Gunn
Story/photos updated
After years of construction, the first of 18 primary flight mirrors has been installed onto NASA’s James Webb Space Telescope (JWST) at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, signifying the start of the final assembly phase for the mammoth observatory that will eventually become the most powerful telescope ever sent to space.
The milestone first mirror installation was achieved this week just ahead of the Thanksgiving holiday as the engineering team, working inside the massive clean room at NASA Goddard, used a robotic arm to precisely lift and lower the gold coated mirror into place on the observatory’s critical mirror holding backplane assembly.
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
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
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 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
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
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.
A comparison of the primary mirror used by Hubble and the primary mirror array used by the James Webb Space Telescope. Photo Credit: NASANASA 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
In the Neil Armstrong Operations and Checkout Building high bay at NASA's Kennedy Space Center in Florida, NASA Administrator Charlie Bolden delivers a “state of the agency” address at NASA's televised fiscal year 2016 budget rollout event with Kennedy Space Center Director Bob Cabana looking on, at right. NASA's Orion, SpaceX Dragon and Boeing CST-100 spacecraft were on display. Photo credit: NASA/Gianni Woods
The Obama Administration today (Feb. 2) proposed a NASA budget allocation of $18.5 Billion for the new Fiscal Year 2016, which amounts to a half-billion dollar increase over the enacted budget for FY 2015, and keeps the key manned capsule and heavy lift rocket programs on track to launch humans to deep space in the next decade and significantly supplements the commercial crew initiative to send our astronauts to low Earth orbit and the space station later this decade.
NASA Administrator Charles Bolden formally announced the rollout of NASA’s FY 2016 budget request today during a “state of the agency” address at the Kennedy Space Center (KSC), back dropped by the three vehicles at the core of the agency’s human spaceflight exploration strategy; Orion, the Boeing CST-100 and the SpaceX Dragon.
“To further advance these plans and keep on moving forward on our journey to Mars, President Obama today is proposing an FY 2016 budget of $18.5 billion for NASA, building on the significant investments the administration has made in America’s space program over the past six years,” Administrator Bolden said to NASA workers and the media gathered at the KSC facility where Orion is being manufactured.
“These vehicles are not things just on paper anymore! This is tangible evidence of what you [NASA] have been doing these past few years.”
In the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, NASA Administrator Charlie Bolden delivers a “state of the agency” address on Feb 2, 2015 at NASA’s televised fiscal year 2016 budget rollout event. Photo credit: NASA/Gianni Woods
Bolden said the $18.5 Billion budget request will enable the continuation of core elements of NASA’s main programs including first launch of the new commercial crew vehicles to orbit in 2017, maintaining the Orion capsule and the Space Launch System (SLS) rocket to further NASA’s initiative to send ‘Humans to Mars’ in the 2030s, extending the International Space Station (ISS) into the next decade, and launching the James Webb Space Telescope in 2018. JWST is the long awaited successor to NASA’s Hubble Space Telescope.
“NASA is firmly on a journey to Mars. Make no mistake, this journey will help guide and define our generation.”
Funding is also provided to enable the manned Asteroid Redirect Mission (ARM) by around 2025, to continue development of the next Mars rover, and to continue formulation studies of a robotic mission to Jupiter’s icy moon Europa.
“That’s a half billion-dollar increase over last year’s enacted budget, and it is a clear vote of confidence in you – the employees of NASA – and the ambitious exploration program you are executing,” said Bolden.
Overall the additional $500 million for FY 2016 translates to a 2.7% increase over FY 2015. That compares to about a 6.4% proposed boost for the overall US Federal Budget amounting to $4 Trillion.
The Boeing CST-100 and the SpaceX Dragon V2 will restore the US capability to ferry astronauts to and from the International Space Station (ISS).
In September 2014, Bolden announced the selections of Boeing and SpaceX to continue development and certification of their proposed spaceships under NASA’s Commercial Crew Program (CCP) and Launch America initiative started back in 2010.
NASA Administrator Charles Bolden (left) announces the winners of NASA’s Commercial Crew Program development effort to build America’s next human spaceships launching from Florida to the International Space Station. Speaking from Kennedy’s Press Site, Bolden announced the contract award to Boeing and SpaceX to complete the design of the CST-100 and Crew Dragon spacecraft. Former astronaut Bob Cabana, center, director of NASA’s Kennedy Space Center in Florida, Kathy Lueders, manager of the agency’s Commercial Crew Program, and former International Space Station Commander Mike Fincke also took part in the announcement. Credit: Ken Kremer- kenkremer.com
Since the retirement of the Space Shuttle program in 2011, all NASA astronauts have been totally dependent on Russia and their Soyuz capsule as the sole source provider for seats to the ISS.
“The commercial crew vehicles are absolutely critical to our journey to Mars, absolutely critical. SpaceX and Boeing have set up operations here on the Space Coast, bringing jobs, energy and excitement about the future with them. They will increase crew safety and drive down costs.”
Meet Dragon V2 – SpaceX CEO Elon pulls the curtain off manned Dragon V2 on May 29, 2014 for worldwide unveiling of SpaceX’s new astronaut transporter for NASA. Credit: SpaceX
CCP gets a hefty and needed increase from $805 Million in FY 2015 to $1.244 Billion in FY 2016.
To date the Congress has not fully funded the Administration’s CCP funding requests, since its inception in 2010.
The significant budget slashes amounting to 50% or more by Congress, have forced NASA to delay the first commercial crew flights of the private ‘space taxis’ from 2015 to 2017.
As a result, NASA has also been forced to continue paying the Russians for crew flights aboard the Soyuz that now cost over $70 million each under the latest contract signed with Roscosmos, the Russian Federal Space Agency.
Boeing CST-100 capsule interior up close. Credit: Ken Kremer – kenkremer.com
Bolden has repeatedly stated that NASA’s overriding goal is to send astronauts to Mars in the 2030s.
To accomplish the ‘Journey to Mars’ NASA is developing the Orion deep space crew capsule and mammoth SLS rocket.
However, both programs had their budgets cut in the FY 2016 proposal compared to FY 2015. The 2015 combined total of $3.245 Billion is reduced in 2016 to $2.863 Billion, or over 10%.
The first test flight of an unmanned Orion atop the SLS is now slated for liftoff on Nov. 2018, following NASA’s announcement of a launch delay from the prior target of December 2017.
Since the Journey to Mars goal is already underfunded, significant cuts will hinder progress.
NASA’s first Orion spacecraft blasts off at 7:05 a.m. atop United Launch Alliance Delta 4 Heavy Booster at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida on Dec. 5, 2014. Launch pad remote camera view. Credit: Ken Kremer – kenkremer.com
There are some losers in the new budget as well.
Rather incomprehensibly funding for the long lived Opportunity Mars Exploration Rover is zeroed out in 2016.
This comes despite the fact that the renowned robot just reached the summit of a Martian mountain at Cape Tribulation and is now less than 200 meters from a science goldmine of water altered minerals.
NASA’s Opportunity Mars rover captures sweeping panoramic vista near the ridgeline of 22 km (14 mi) wide Endeavour Crater’s western rim. The center is southeastward and the distant rim is visible in the center. An outcrop area targeted for the rover to study is at right of ridge. This navcam panorama was stitched from images taken on May 10, 2014 (Sol 3659) and colorized. Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer-kenkremer.com
Funding for the Lunar Reconnaissance Orbiter (LRO) is also zeroed out in FY 2016.
Both missions continue to function quite well with very valuable science returns. They were also zeroed out in FY 2015 but received continued funding after a senior level science review.
So their ultimate fate is unknown at this time.
Overall, Bolden was very upbeat about NASA’s future.
“I can unequivocally say that the state of NASA is strong,” Bolden said.
He concluded his remarks saying:
“Because of the dedication and determination of each and every one of you in our NASA Family, America’s space program is not just alive, it is thriving! Together with our commercial and international partners, academia and entrepreneurs, we’re launching the future. With the continued support of the Administration, the Congress and the American people, we’ll all get there together.”
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Center section of the "pathfinder" (test) backplane of NASA's James Webb Space Telescope is hoisted into place in the assembly stand in NASA Goddard's giant cleanroom. Engineers will practice mirror installations over the next several months. Credit: NASA/Chris Gunn
The central piece of the “pathfinder” backplane that will hold all the mirrors for NASA’s James Webb Space Telescope (JWST) has arrived at the agency’s Goddard Space Flight Center in Maryland for critical assembly testing on vital parts of the mammoth telescope.
The pathfinder backplane arrived at Goddard in July and has now been hoisted in place onto a huge assembly stand inside Goddard’s giant cleanroom where many key elements of JWST are being assembled and tested ahead of the launch scheduled for October 2018.
The absolutely essential task of JWST’s backplane is to hold the telescopes 18 segment, 21-foot-diameter primary mirror nearly motionless while floating in the utterly frigid space environment, thereby enabling the telescope to peer out into deep space for precise science gathering measurements never before possible.
Over the next several months, engineers will practice installing two spare primary mirror segments and one spare secondary mirror onto the center part of the backplane.
JWST pathfinder backplane has arrived here at NASA Goddard clean room.
JWST is being assembled here inside the world’s largest clean room at NASA Goddard Space Flight Center, Greenbelt, Md. Primary mirror segments stored in silver colored containers at top left. Technicians practice mirror installation on test piece of backplane (known as the BSTA or Backplane Stability Test Article) at center, 3 hexagonals. Pathfinder backplane has been hoisted into telescope assembly bays at right. Credit: Ken Kremer- kenkremer.com
The purpose is to gain invaluable experience practicing the delicate procedures required to precisely install the hexagonal shaped mirrors onto the actual flight backplane unit after it arrives.
The telescopes primary and secondary flight mirrors have already arrived at Goddard.
The mirrors must remained precisely aligned in space 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.
The backplane and every other component must function and unfold perfectly and to precise tolerances in space because JWST has not been designed for servicing or repairs by astronaut crews voyaging beyond low-Earth orbit into deep space, William Ochs, Associate Director for JWST at NASA Goddard told me in an interview during a visit to JWST at Goddard.
Watch this video showing movement of the pathfinder backplane into the Goddard cleanroom.
Video Caption: This is a time-lapse video of the center section of the ‘pathfinder’ backplane for NASA’s James Webb Space Telescope being moved into the clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Credit: NASA/Chris Gunn
The actual flight backplane is comprised of three segments – the main central segment and a pair of outer wing-like parts which will be folded over into launch configuration 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.
Both the backplane flight unit and the pathfinder unit, which consists only of the center part, are being assembled and tested by prime contractor Northrop Grumman in Redondo Beach, California.
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 test unit was then loaded into a C-5, flown to the U.S. Air Force’s Joint Base Andrews in Maryland and unloaded for transport by trailer truck to NASA Goddard in Greenbelt, Maryland.
JWST is the successor to the 24 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.
A comparison of the primary mirror used by Hubble and the primary mirror array used by the James Webb Space Telescope. Photo Credit: NASA
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.
Read my story about the recent unfurling test of JWST’s sunshade – here.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
The Webb telescope backplane “pathfinder” or practice-model was unloaded from a C-5 aircraft at the U.S. Air Force’s Joint Base Andrews in Maryland. Image Credit: NASA/Desiree Stover Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom. Credit: NASA/ESA
The sunshield test unit on NASA's James Webb Space Telescope is unfurled for the first time. Credit: NASA
GODDARD SPACE FLIGHT CENTER, MD – The huge Sunshield test unit for NASA’s James Webb Space Telescope (JWST) has been successfully unfurled for the first time in a key milestone ahead of the launch scheduled for October 2018.
Engineers stacked and expanded the tennis-court sized Sunshield test unit last week inside the cleanroom at a Northrop Grumman facility in Redondo Beach, California.
NASA reports that the operation proceeded perfectly the first time during the test of the full-sized unit.
The Sunshield and every other JWST component must unfold perfectly and to precise tolerances in space because it has not been designed for servicing or repairs by astronaut crews voyaging beyond low-Earth orbit into deep space, William Ochs, Associate Director for JWST at NASA Goddard told me in an exclusive interview.
Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom. Credit: NASA/ESA
The five layered Sunshield is the largest component of the observatory and acts like a parasol.
Its purpose is to protect Webb from the suns heat and passively cool the telescope and its quartet of sensitive science instruments via permanent shade to approximately 45 kelvins, -380 degrees F, -233 C.
The kite-shaped Sunshield provides an effective sun protection factor or SPF of 1,000,000. By comparison suntan lotion for humans has an SPF of 8 to 40.
Two sides of the James Webb Space Telescope (JWST). Credit: NASA
The extreme cold is required for the telescope to function in the infrared (IR) wavelengths and enable it to look back in time further than ever before to detect distant objects.
The shield separates the observatory into a warm sun-facing side and a cold anti-sun side.
Its five thin membrane layers also provides a stable thermal environment to keep the telescopes 18 primary mirror segments properly aligned for Webb’s science investigations.
JWST is the successor to the 24 year old Hubble Space Telescope and will become the most powerful telescope ever sent to space.
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.
Webb will launch folded up inside the payload fairing of an ESA Ariane V ECA rocket from the Guiana Space Center in Kourou, French Guiana.
In launch configuration, the Sunshield will surround the main mirrors and instruments like an umbrella.
During the post launch journey to the L2 observing orbit at the second Sun-Earth Lagrange point nearly a million miles (1.5 million Km) from Earth, the telescopes mirrors and sunshield will begin a rather complex six month long unfolding and calibration process.
The science instruments have been mounted inside the ISIM science module and are currently undergoing critical vacuum chamber testing at NASA Goddard Space Flight Center which provides overall management and systems engineering.
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 mirror segments have arrived at NASA Goddard where I’ve had the opportunity to observe and report on work in progress.
Stay tuned here for Ken’s continuing JWST, MMS, ISS, Curiosity, Opportunity, SpaceX, Orbital Sciences, Boeing, Orion, MAVEN, MOM, Mars and more Earth and Planetary science and human spaceflight news.
Each of the four panels is a combination of two separate exposures made by the Hubble Space Telescope as it tracked Comet ISON's position. Had the comet been in any of these frames, it would have appeared as a small fuzzy glow or stellar point(s) in the center. The stars are trailed because the camera tracked the comet. Credit: NASA/ESA
On December 18, the Hubble Space Telescope slewed to Comet ISON’s expected position and found nothing down to the incredibly faint magnitude of 25. According to astronomer Hal Weaver, who planned the ISON search, that limit implies any remaining fragments would have to be smaller than about 500 feet (160 meters) in diameter.
Composite photo of one of two Comet ISON locations photographed by the Hubble Space Telescope. No trace of the comet is visible. Credit: NASA/ESA
Nothing is visible in any of the images in the photo panel except trailed stars and galaxies, reflections and the occasional zap of a cosmic ray. After ISON was torn asunder by the sun, there existed the possibility that comet’s remains would follow a slightly different orbit. To make sure he was covered, Weaver photographed two separate comet positions, stacking several exposures together.
Comet ISON photographed at a second location. Again, nothing detected. Credit: NASA/ESA
“The images have been combined so that features not at the same place in the various images are suppressed. Any comet fragments would show up more clearly in this composite, though stars still show up as faint streaks”, writes Zolt Lavay, author of the ISONblog at the Hubble site.
Again, nothing shows up in these either. While no one can say that ISON has completely disappeared, we now know that at the very least it’s broken into pieces too small for even Hubble to see. What was once a beautiful sight in binoculars has expanded into a vast cloud of gas and dust thinner than Ebenezer Scrooge’s gruel.
