And now, after nine years of service, NASA has officially announced that the Kepler Space Telescope will be retiring. With no fuel remaining to conduct its science observations, NASA has decided to leave the telescope in its current safe orbit (well away from Earth). Far from being a sad occasion, Kepler’s retirement is an opportunity to reflect upon the immense accomplishments of this telescope and how it revolutionized the study of exoplanets.
Paul Geithner, Deputy Project Manager – Technical for the James Webb Space Telescope (JWST) at NASA’s Goddard Space Flight Center where he focuses on technical oversight, and the resolution and verification of technical issues. Paul last visited us on October 7, 2017, almost two years ago to the day, and tonight joins us to give us an update about JWST.
You can learn more about Paul by visiting https://jwst.nasa.gov/meet-geithner.html
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Welcome to the 575th Carnival of Space! The Carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. We have a fantastic roundup today including news from the IAU, so now, on to this week’s worth of stories! Continue reading “Carnival of Space #575”
The James Webb Space Telescope is like the party of the century that keeps getting postponed. Due to its sheer complexity and some anomalous readings that were detected during vibration testing, the launch date of this telescope has been pushed back many times – it is currently expected to launch sometime in 2021. But for obvious reasons, NASA remains committed to seeing this mission through.
Once deployed, the JWST will be the most powerful space telescope in operation, and its advanced suite of instruments will reveal things about the Universe that have never before been seen. Among these are the atmospheres of extra-solar planets, which will initially consist of gas giants. In so doing, the JWST will refine the search for habitable planets, and eventually begin examining some potential candidates.
The JWST will be doing this in conjunction with the Transiting Exoplanet Survey Satellite (TESS), which deployed to space back in April of 2018. As the name suggests, TESS will be searching for planets using the Transit Method (aka. Transit Photometry), where stars are monitored for periodic dips in brightness – which are caused by a planet passing in front of them relative to the observer.
Some of Webb’s first observations will be conducted through the Director’s Discretionary Early Release Science program – a transiting exoplanet planet team at Webb’s science operation center. This team is planning on conducting three different types of observations that will provide new scientific knowledge and a better understanding of Webb’s science instruments.
As Jacob Bean of the University of Chicago, a co-principal investigator on the transiting exoplanet project, explained in a NASA press release:
“We have two main goals. The first is to get transiting exoplanet datasets from Webb to the astronomical community as soon as possible. The second is to do some great science so that astronomers and the public can see how powerful this observatory is.”
As Natalie Batalha of NASA Ames Research Center, the project’s principal investigator, added:
“Our team’s goal is to provide critical knowledge and insights to the astronomical community that will help to catalyze exoplanet research and make the best use of Webb in the limited time we have available.”
For their first observation, the JWST will be responsible for characterizing a planet’s atmosphere by examining the light that passes through it. This happens whenever a planet transits in front of a star, and the way light is absorbed at different wavelengths provides clues as to the atmosphere’s chemical composition. Unfortunately, existing space telescopes have not had the necessary resolution to scan anything smaller than a gas giant.
The JWST, with its advanced infrared instruments, will examine the light passing through exoplanet atmospheres, split it into a rainbow spectrum, and then infer the atmospheres’ composition based on which sections of light are missing. For these observations, the project team selected WASP-79b, a Jupiter-sized exoplanet that orbits a star in the Eridanus constellation, roughly 780 light-years from Earth.
The team expects to detect and measure the abundances of water, carbon monoxide, and carbon dioxide in WASP-79b, but is also hoping to find molecules that have not yet been detected in exoplanet atmospheres. For their second observation, the team will be monitoring a “hot Jupiter” known as WASP-43b, a planet which orbits its star with a period of less than 20 hours.
Like all exoplanets that orbit closely to their stars, this gas giant is tidally-locked – where one side is always facing the star. When the planet is in front of the star, astronomers are only able to see its cooler backside; but as it orbits, the hot day-side slowly comes into view. By observing this planet for the entirety of its orbit, astronomers will be able to observe those variations (known as a phase curve) and use the data to map the planet’s temperature, clouds, and atmospheric chemistry.
This data will allow them to sample the atmosphere to different depths and obtain a more complete picture of the planet’s internal structure. As Bean indicated:
“We have already seen dramatic and unexpected variations for this planet with Hubble and Spitzer. With Webb we will reveal these variations in significantly greater detail to understand the physical processes that are responsible.”
For their third observation, the team will be attempting to observe a transiting planet directly. This is very challenging, seeing as how the star’s light is much brighter and therefore obscures the faint light being reflected off the planet’s atmosphere. One method for addressing this is to measure the light coming from a star when the planet is visible, and again when it disappears behind the star.
By comparing the two measurements, astronomers can calculate how much light is coming from the planet alone. This technique works best for very hot planets that glow brightly in infrared light, which is why they selected WASP-18b for this observation – a hot Jupiter that reaches temperatures of around 2,900 K (2627 °C; 4,800 °F). In the process, they hope to determine the composition of the planet’s smothering stratosphere.
In the end, these observations will help test the abilities of the JWST and calibrate its instruments. The ultimate goal will be to examine the atmospheres of potentially-habitable exoplanets, which in this case will include rocky (aka. “Earth-like”) planets that orbit low mass, dimmer red dwarf stars. In addition to being the most common star in our galaxy, red dwarfs are also believed to be the most likely place to find Earth-like planets.
“TESS should locate more than a dozen planets orbiting in the habitable zones of red dwarfs, a few of which might actually be habitable. We want to learn whether those planets have atmospheres and Webb will be the one to tell us. The results will go a long way towards answering the question of whether conditions favorable to life are common in our galaxy.”
The James Webb Space Telescope will be the world’s premier space science observatory once deployed, and will help astronomers to solve mysteries in our Solar System, study exoplanets, and observe the very earliest periods of the Universe to determine how its large-scale structure evolved over time. For this reason, its understandable why NASA is asking that the astronomical community be patient until they are sure it will deploy successfully.
When the payoff is nothing short of ground-breaking discoveries, it’s only fair that we be willing to wait. In the meantime, be sure to check out this video about how scientists study exoplanet atmospheres, courtesy of the Space Telescope Science Institute:
The Kepler space telescope has had a relatively brief but distinguished career of service with NASA. Having launched in 2009, the space telescope has spent the past nine years observing distant stars for signs of planetary transits (i.e. the Transit Method). In that time, it has been responsible for the detection of 2,650 confirmed exoplanets, which constitutes the majority of the more than 38oo planets discovered so far.
Earlier this week, the Kepler team was notified that the space telescope’s fuel tank is running very low. NASA responded by placing the spacecraft in hibernation in preparation for a download of its scientific data, which it collected during its latest observation campaign. Once the data is downloaded, the team expects to start its last observation campaign using whatever fuel it has left.
In order to send the data back home, the spacecraft will point is large antenna back towards Earth and transmit it via the Deep Space Network. However, the DSN is responsible for transmitting data from multiple missions and time needs to be allotted in advance. Kepler is scheduled to send data from its 18th campaign back in August, and will remain in a stable orbit and safe mode in order to conserve fuel until then.
On August 2nd, the Kepler team will command the spacecraft to awaken and will maneuver the craft to the correct orientation to transmit the data. If all goes well, they will begin Kepler’s 19th observation campaign on August 6th with what fuel the spacecraft still has. At present, NASA expects that the spacecraft will run out of fuel in the next few months.
However, even after the Kepler mission ends, scientists and engineers will continue to mine the data that has already been sent back for discoveries. According to a recent study by an international team of scientists, 24 new exoplanets were discovered using data from the 10th observation campaign, which has brought the total number of Kepler discoveries to 2,650 confirmed exoplanets.
In the coming years, many more exoplanet discoveries are anticipated as the next-generation of space telescopes begin collecting their first light or are deployed to space. These include the Transiting Exoplanet Survey Satellite (TESS), which launched this past April, and the James Webb Space Telescope (JWST) – which is currently scheduled to launch sometime in 2021.
However, it will be many years before any mission can rival the accomplishments and contributions made by Kepler! Long after she is retired, her legacy will live on in the form of her discoveries.
When it is deployed to space, the James Webb Space Telescope (JWST) will be the most powerful and advanced telescope ever deployed. As the spiritual and scientific successor to the Hubble, Spitzer, and Kepler Space Telescopes, this space observatory will use its advanced suite of infrared instruments to look back at the early Universe, study the Solar System, and help characterize extra-solar planets.
Unfortunately, after many delays, there’s some good news and bad news about this mission. The good news is that recently, the Independent Review Board (IRB) established by NASA to assess the progress on the JWST unanimously decided that work on the space telescope should continue. The bad news is that NASA has decided to push the launch date back again – this time to March 30th, 2021.
As part of their assessment, the IRB was established in April of 2018 to address a range of factors influencing Webb’s schedule and performance. These included the technical challenges and tasks that need to be tackled by its primary contractor (Northrop Grumman) before the mission can launch. A summary of the report’s recommendations, and NASA’s response, can be read here.
In the report, the IRB identified technical issues, which including human errors, that they claim have greatly impacted the development schedule. As they stated in their Overview:
“The observation that there are no small JWST integration and test problems was not initially recognized by the Webb IRB, and this also may be true of others involved with JWST. It is a most important observation that will be apparent in subsequent Findings and Recommendations. It is caused by the complexity and highly integrated nature of the observatory. Specifically, it implies, as an example, that a very small human error or test anomaly can impact the schedule by months and the cost by tens of millions of dollars.”
The anomaly mentioned in the report refers to the “anomalous readings” that were detected from the telescope during vibration testing back in December 2016. NASA responded to this by giving the project up to 4 months of schedule reserve by extending the launch window. However, in 2017, NASA delayed the launch window again by 5 months, from October 2018 to a between March and June 2019.
This delay was requested by the project team, who indicated that they needed to address lessons learned from the initial folding and deployment of the observatory’s sun shield. In February of 2018, the Government Accountability Office (GAO) issued a report that expressed concerns over further delays and cost overruns. Shortly thereafter, the JWST’s Standing Review Board (SRB) made an independent assessment of the remaining tasks.
In May of 2018, NASA issued a statement indicating that they now estimated that the launch window would be some time in May 2020. However, they chose to await the findings of the IRB and consider the data from the JWST’s Standing Review Board before making the final determination. The new launch date was set to accommodate environmental testing and work performances challenges on the sunshield and propulsion system.
According to the IRB report, this latest delay will also result in a budget overrun. “As a result of the delay, Webb’s total lifecycle cost to support the March 2021 launch date is estimated at $9.66 billion,” they concluded. “The development cost estimate to support the new launch date is $8.8B (up from the $8B development cost estimate established in 2011).”
As Jim Bridenstine, the NASA Administrator, indicated in a message to the NASA workforce on Wednesday about the report:
“Webb is vital to the next generation of research beyond NASA’s Hubble Space Telescope. It’s going to do amazing things – things we’ve never been able to do before – as we peer into other galaxies and see light from the very dawn of time. Despite major challenges, the board and NASA unanimously agree that Webb will achieve mission success with the implementation of the board’s recommendations, many of which already are underway.”
In the end, the IRB, SRB and NASA are all in total agreement that the James Webb Space Telescope is a crucial mission that must be seen through. In addition to shedding light on a number of mysteries of the Universe – ranging from the earliest stars and galaxies in the Universe to exoplanet habitability – the JWST will also complement and enhance the discoveries made by other missions.
“The more we learn more about our universe, the more we realize that Webb is critical to answering questions we didn’t even know how to ask when the spacecraft was first designed. Webb is poised to answer those questions, and is worth the wait. The valuable recommendations of the IRB support our efforts towards mission success; we expect spectacular scientific advances from NASA’s highest science priority.”
The JWST will also be the first telescope of its kind, being larger and more complex than any previous space telescope – so challenges were anticipated from its very inception. In addition, the final phase consists of some of the most challenging work, where the 6.5-meter telescope and science payload element are being joined with the spacecraft element to complete the observatory.
The science team also needs to ensure that the observatory can be folded up to fit inside the Ariane 5 rocket that will launch it into space. They also need to ensure that it will unfold again once it reaches space, deploy its sunshield, mirrors and primary mirror. Beyond that, there are also the technical challenges of building a complex observatory that was created here on Earth, but designed to operate in space.
As a collaborative project between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA), the JWST is also representative of the new era of international cooperation. As such, no one wishes to see the mission abandoned so close to completion. In the meantime, any delays that allow for extra testing will only ensure success in the long run.
Good luck JWST, we look forward to hearing about your first discoveries!
But just how many planets is TESS expected to find? That was the subject of a new study by a team researchers who attempted to estimate just how many planets TESS is likely to discover, as well as the physical properties of these planets and the stars that they orbit. Altogether, they estimate TESS will find thousands of planets orbiting a variety of stars during its two-year primary mission.
The study, titled “A Revised Exoplanet Yield from the Transiting Exoplanet Survey Satellite (TESS)“, recently appeared online. The study was led by Thomas Barclay, an associate research scientist at the NASA Goddard Space Flight Center and the University of Maryland, and included Joshua Pepper (an astrophysicist at Lehigh University) and Elisa Quintana (a research scientist with the SETI Institute and NASA Ames Research Center).
As Thomas Barclay told Universe Today via email:
“TESS builds off the legacy of Kepler. Kepler was primarily a statistical mission and taught us that planets are everywhere. However, it wasn’t optimized for finding excellent individual planets for further study. Now that we know planets are common, we can launch something like TESS to search for the planets that we will undertake intensive studies of using ground and space-based telescopes. Planets that TESS will find will on average be 10x closer and 100x brighter.”
For the sake of their study, the team created a three-step model that took into account the stars TESS will observe, the number of planets each one is likely to have, and the likelihood of TESS spotting them. These included the kinds of planets that would be orbiting around dwarf stars ranging from A-type to K-type (like our Sun), and lower-mass M-type (red dwarf) stars.
“To estimate how many planets TESS will find we took stars that will be observed by TESS and simulated a population of planets orbiting them,” said Barclay. “The exoplanet population stats all come from studies that used Kepler data. Then, using models of TESS performance, we estimated how many of those planets would be detected by TESS. This is where we get our yield numbers from.”
The first step was straightforward, thanks to the availability of the Candidate Target List (CTL) – a prioritized list of target stars that the TESS Target Selection Working Group determined were the most suitable stars for detecting small planets. They then ranked the 3.8 million stars that are included in the latest version based on their brightness and radius and determined which of these TESS is likely to observe.
The second step consisted of assigning planets to each star based on a Poisson distribution, a statistical technique where a given number is assigned to each star (in this case, 0 or more). Each planet was then assigned six physical properties drawn at random, including an orbital period, a radius, an eccentricity, a periastron angle, an inclination to our line of sight, and a mid-time of first transit.
Last, they attempted to estimate how many of these planets would generate a detectable transit signal. As noted, TESS will rely on the Transit Method, where periodic dips in a star’s brightness are used to determine the presence of one or more orbiting planets, as well as place constraints on their sizes and orbital periods. For this, they considered the flux contamination of nearby stars, the number of transits, and the transit duration.
Ultimately, they determined with 90% confidence that TESS is likely to detect 4430–4660 new exoplanets during its two years mission:
“The results is that we predict that TESS will find more than 4000 planets, with hundreds smaller than twice the size of Earth. The primary goal of TESS is to find planets that are bright enough for ground-based telescope to measure their mass. We estimate that TESS could lead to triple the number of planets smaller than 4 Earth-radii with mass measurements.”
As of April 1st, 2018, a total 3,758 exoplanets have been confirmed in 2,808 systems, with 627 systems having more than one planet. In other words, Barclay and his team estimate that the TESS mission will effectively double the number of confirmed exoplanets and triple the number of Earth-sized and Super-Earth’s during its primary mission.
This will begin after a series of orbital maneuvers and engineering tests, which are expected to last for about two months. With the exoplanet catalog thus expanded, we can expect that there will be many more “Earth-like” candidates available for study. And while we still will not be able to determine if any of them have life, we may perhaps find some that show signs of a viable atmosphere and water on the surfaces.
The hunt for life beyond Earth will continue for many years to come! And in the meantime, be sure to enjoy this video about the TESS mission, courtesy of NASA:
Once it deploys, the James Webb Space Telescope (JWST) will be the most powerful and technically complex space telescope ever deployed. Using its powerful suite of infrared-optimized instruments, this telescope will be able to study the earliest stars and galaxies in the Universe, extra-solar planets around nearby stars, and the planets, moons and asteroids of our Solar System.
Unfortunately, due to its complexity and the need for more testing, the launch of the JWST has been subject to multiple delays. And as of this morning, NASA announced that the launch JWST has been delayed yet again. According to a statement issued by the agency, the launch window for the JWST is now targeted for sometime around May 2020.
The decision came after an independent assessment by the project’s Standing Review Board (SRB) of the remaining tasks, all of which are part of the final stage of integration and testing before the JWST launches. These tasks consist of integrating the combined optics and science instruments onto the spacecraft element, then testing them to ensure that they will deploy properly and work once they are in space.
This assessment came on the heels of a report issued by the Government Accountability Office (GAO) in February that expressed concerns over further delays and cost overruns. These concerns were based on the fact that it is typically in the final phase when problems are found and schedules revised, and that only 1.5 months of schedule reserved remained (at the time) until the end of the telescope’s launch window – which was scheduled for 2019.
But as acting NASA Administrator Robert Lightfoot stressed, the JWST is still a go:
“Webb is the highest priority project for the agency’s Science Mission Directorate, and the largest international space science project in U.S. history. All the observatory’s flight hardware is now complete, however, the issues brought to light with the spacecraft element are prompting us to take the necessary steps to refocus our efforts on the completion of this ambitious and complex observatory.”
NASA also announced that it is establishing an external Independent Review Board (IRB) chaired by Thomas Young – a highly-respected NASA and industry veteran who has a long history of chairing advisory committees and analyzing organizational and technical issues. The IRB findings, along with the SRB data, will be considered by NASA to set a more specific launch date, and will be presented to Congress this summer.
In the meantime, NASA and the European Space Agency (ESA) will be setting a new launch readiness date for the Ariane 5 rocket that will bring the JWST into space. Once a launch date is set, NASA will also be providing a cost estimate that may exceed the $8 billion budget cap established by Congress in 2011. This too is in keeping with the GAO’s report, which predicted cost overruns.
For those who have been following the JWST’s development, this news should come as no surprise. Due to its complexity and the need for extensive testing, the launch of the JWST has been delayed several times in recent years. In addition, the final phase consists of some of the most challenging work, where the 6.5-meter telescope and science payload element are being joined with the spacecraft element to complete the observatory.
In addition, the science team also needs to ensure that the observatory can be folded up to fit inside the Ariane 5 rocket that will launch it into space. They also need to ensure that it will unfold again once it reaches space, deploying its sunshield, mirrors and primary mirror. Beyond that, there are also the technical challenges of building a complex observatory that was created here on Earth, but designed to operate in space.
Not only does all of this represent a very technically-challenging feet, it is the first time that any space telescope has had to perform it. Already, the JWST has completed an extensive range of tests to ensure that it will reach its orbit roughly 1.6 million km (1 million mi) from Earth. And while delays can be discouraging, they also increase the likelihood of mission success.
As Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate, stated:
“Considering the investment NASA and our international partners have made, we want to proceed systematically through these last tests, with the additional time necessary, to be ready for a May 2020 launch.”
The next step in testing will take several months, and will consist of the spacecraft element undergoing tests to simulate the vibrational, acoustic and thermal environments it will experience during its launch and operations. Once complete, the project engineers will integrate and test the fully assembled observatory and verify that all its components work together properly.
And then (fingers crossed!) this ambitious telescope will finally be ready to take to space and start collecting light. In so doing, scientists from all around the world hope to shed new light on some of the most fundamental questions of science – namely, how did the Universe evolve, is their life in our Solar System beyond Earth, are their habitable worlds beyond our Solar System, and are there other civilizations out there?
Bottom line, NASA remains committed to deploying the James Webb Space Telescope. So even if the answers to these questions are delayed a little, they are still coming!
Since its deployment in March of 2009, the Kepler space telescope has been a boon for exoplanet-hunters. As of March 8th, 2018, a total of 3,743 exoplanets have been confirmed, 2,649 of which were discovered by Kepler alone. At the same time, the telescope has suffered its share of technical challenges. These include the failure of two reaction wheels, which severely hampered the telescope’s ability to conduct its original mission.
Nevertheless, the Kepler team was able to return the telescope to a stable configuration by using small amounts of thruster fuel to compensate for the failed reaction wheels. Unfortunately, after almost four years conducting its K2 observation campaign, the Kepler telescope is now running out fuel. Based on its remaining fuel and rate of consumption, NASA estimates that the telescope’s mission will end in a few months.
For years, the Kepler space telescope has been locating planets around distant stars using the Transit Method (aka. Transit Photometry). This consists of monitors stars for periodic dips in brightness, which are caused by a planet passing in front of the star (i.e. transiting). Of all the methods used to hunt for exoplanets, the Transit Method is considered the most reliable, accounting for a total of 2900 discoveries.
Naturally, this news comes as a disappointment to astronomers and exoplanet enthusiasts. But before anyone starts lamenting the situation, they should keep some things in mind. For one, the Kepler mission has managed to last longer than anyone expected. Ever since the K2 campaign began, the telescope has been required to shift its field of view about every three months to conduct a new observation campaign.
Based on their original estimates, the Kepler team believed they had enough fuel to conduct 10 more campaigns. However, the mission has already completed 16 campaigns and the team just began their 17th. As Charlie Sobeck, a system engineer for the Kepler space telescope mission, explained in a recent NASA press statement:
“Our current estimates are that Kepler’s tank will run dry within several months – but we’ve been surprised by its performance before! So, while we anticipate flight operations ending soon, we are prepared to continue as long as the fuel allows. The Kepler team is planning to collect as much science data as possible in its remaining time and beam it back to Earth before the loss of the fuel-powered thrusters means that we can’t aim the spacecraft for data transfer. We even have plans to take some final calibration data with the last bit of fuel, if the opportunity presents itself.”
So while the mission is due to end soon, the science team hopes to gather as much scientific data as possible and beam it back to Earth before then. They also hope to gather some final calibration data using the telescope’s last bit of fuel, should the opportunity present itself. And since they cannot refuel the spacecraft, they hope to stop collecting data so they can use their last bit of fuel to point the spacecraft back towards Earth and bring it home.
“Without a gas gauge, we have been monitoring the spacecraft for warning signs of low fuel— such as a drop in the fuel tank’s pressure and changes in the performance of the thrusters,” said Sobeck. “But in the end, we only have an estimate – not precise knowledge. Taking these measurements helps us decide how long we can comfortably keep collecting scientific data.”
This has been standard practice for many NASA missions, where enough fuel has been reserved to conduct one last maneuver. For example, the Cassini mission had to reserve fuel in order to descend into Saturn’s atmosphere so it would avoid colliding with one of its moons and contaminating a potentially life-bearing environment. Satellites also regularly conduct final maneuvers to ensure they don’t crash into other satellites or fall to Earth.
While deep-space missions like Kepler are in no danger of crashing to Earth or contaminating a sensitive environment, this final maneuver is designed to ensure that the science team can squeeze every last drop of data from the spacecraft. So before the mission wraps up, we can expect that this venerated planet-hunter will have some final surprises for us!
In the coming years, next-generation telescopes will be taking to space to pick up where Kepler and other space telescopes left off. These include the Transiting Exoplanet Survey Satellite(TESS), which will be conducting Transit surveys shortly after it launches in April of 2018. By 2019, the James Webb Space Telescope (JWST) will also take to space and use its powerful infrared instruments to aid in the hunt for exoplanets.
So while we will soon be saying goodbye to the Kepler mission, its legacy will live on. In truth, the days of exoplanet discovery are just getting started!
Once deployed, the James Webb Space Telescope (JWST) will be the most powerful telescope ever built. As the spiritual and scientific successor to the Hubble, Spitzer, and Kepler space telescopes, this space observatory will use its advanced suite of infrared instruments to the look back at the earliest stars and galaxies, study the Solar System in depth, and help characterize extra-solar planets (among other things).
Unfortunately, the launch of the JWST has been subject to multiple delays, with the launch date now set for some time in 2019. Luckily, on Thursday, March 8th, engineers at the Northrop Grumman company headquarters began the final step in the observatory’s integration and testing. Once complete, the JWST will be ready to ship to French Guiana, where it will be launched into space.
This final phase consisted of removing the combined optics and science instruments from their shipping containers – known as the Space Telescope Transporter for Air, Road and Sea (STTARS) – which recently arrived after being testing at NASA’s Johnson Space Center in Houston. This constitutes half the observatory, and includes the telescope’s 6.5 meter (21.3 foot) golden primary mirror.
The science payload was also tested at NASA’s Goddard Space Flight Center last year to ensure it could handle the vibrations associated with space launches and the temperatures and vacuum conditions of space. The other half of the observatory consists of the integrated spacecraft and sunshield, which is in the final phase of assembly at the Northrop Grumman company headquarters.
These will soon undergo a launch environment test to prove that they are ready to be combined with the science payload. Once both halves are finished being integrated, addition testing will be performed to guarantee the fully assembled observatory can operate at the L2 Earth-Sun Lagrange Point. As Eric Smith, the program director for the JWST at NASA Headquarters, said in a recent NASA press statement:
“Extensive and rigorous testing prior to launch has proven effective in ensuring that NASA’s missions achieve their goals in space. Webb is far along into its testing phase and has seen great success with the telescope and science instruments, which will deliver the spectacular results we anticipate.”
These final tests are crucial to ensuring that that the observatory deploys properly and can operate once it is in space. This is largely because of the telescope’s complicated design, which needs to be folded in order to fit inside the Ariane 5 rocket that it will carry it into space. Once it reaches its destination, the telescope will have to unfold again, deploying its sunshield, mirrors and primary mirror.
Not only does all of this represented a very technically-challenging feet, it is the first time that any space telescope has had to perform it. Beyond that, there are also the technical challenges of building a complex observatory that is designed to operate in space. While the JWST’s optics and science instruments were all built at room temperature here on Earth, they had to be designed to operate at cryogenic temperatures.
As such, its mirrors had to be precisely polished and formed that they would achieve the correct shape once they cool in space. Similarly, its sunshield will be operating in a zero gravity environment, but was built and tested here on Earth where the gravity is a hefty 9.8 m/s² (1 g). In short, the James Webb Space Telescope is the largest and most complex space telescope ever built, and is one of NASA’s highest priority science projects.
It is little wonder then why NASA has had to put the JWST through such a highly-rigorous testing process. As Smith put it:
“At NASA, we do the seemingly impossible every day, and it’s our job to do the hardest things humankind can think of for space exploration. The way we achieve success is to test, test and retest, so we understand the complex systems and verify they will work.”
Knowing that the JWST is now embarking on the final phase of its development – and that its engineers are confident it will perform up to task – is certainly good news. Especially in light of a recent report from the US Government Accountability Office (GAO), which stated that more delays were likely and that the project would probably exceed its original budget cap of $8 billion.
As the report indicated, it is the final phase of integration and testing where problems are most likely to be found and schedules revised. However, the report also stated that “Considering the investment NASA has made, and the good performance to date, we want to proceed very systematically through these tests to be ready for a Spring 2019 launch.”
In other words, there is no indication whatsoever that Congress is considering cancelling the project, regardless of further delays or cost overruns. And when the JWST is deployed, it will use its 6.5 meter (21-foot) infrared-optimized telescopes will search to a distance of over 13 billion light years, allow astronomers to study the atmospheres of Solar Planets, exoplanets, and other objects within our Solar System.
So while the JWST may not make its launch window in 2019, we can still expect that it will be taking to space in the near future. And when it does, we can also expect that what it reveals about our Universe will be mind-blowing!