NASA
NASA

The Challenges of Building the Hubble Telescope’s Replacement

NASA
NASA

Since 1990, the Hubble telescope has brought us photos that are as beautiful as they are scientifically important. But there’s a limit to what Hubble can see—so space agencies from around the world are collaborating to create a better, more powerful, and literally bigger telescope: the James Webb Space Telescope (JWST), which is projected to launch in 2018. In the SXSW panel “Beyond Hubble: Building NASA’s Next Great Telescope,” scientists and engineers discussed what the Webb telescope will look for and all the engineering challenges that go into actually building the instrument.

What JWST Will Do—And How It Will Do It

According to Alberto Conti, Innovation Scientist at the Space Telescope Science Institute, the Webb telescope is a versatile instrument that has four main goals: To find the first stars, study galaxy evolution, study planet formation, and find habitable planets that might contain water (and, therefore, might also have life). “We build telescopes because they’re time machines,” Conti says. “They tell us about how the universe came to be, and how it works.” Scientists hope that Webb will answer questions like: How did the universe form? Is our solar system unique? Are we alone?

In order to answer these questions, JWST needs to be big—really big. One hundred times more powerful than Hubble, the four-story-tall, infrared optimized telescope will be comprised of 18 hexagonal mirrors that total 21.3 feet in diameter which will allow it to take pictures of faraway worlds, and an 80-foot-long sun shield that will keep the telescope’s eyes cold enough to snap those photos.

While Hubble can capture images of planets the size of Jupiter, JWST will be able to look for planets from the size of Neptune down to the size of Earth, according to Charles Mountain, the director of the Space Science Telescope Institute. And it will do it by looking for infrared spectrums. “On the infrared spectrum, there are three planets that we know a lot about: Venus, Mars, and Earth,” Mountain says. If, using JWST, they can find planets with infrared signatures similar to Earth’s, they might be goldilocks planets—just right to have life. “If we find life, it’ll be as profound as Darwin and Copernicus rolled into one,” Mountain says. “It will bring about a change in our world—we’ll realize we’re not as special that we thought, that evolution happened elsewhere.”

Looking for life begins by looking for stars, because planets that can harbor life will be orbiting around stars. JWST can also use infrared to peer through clouds of gas. “The idea is that we can see thousands of stars embedded in gas clouds because we have the right set of eyes,” Conti says. By looking at the spectra of the disks, Webb will be able to determine what constituents of those disks create planetary systems.

The Engineering Challenges

Building JWST hasn’t been a cakewalk. It has required both creativity and tons of collaboration between scientists, engineers, and companies in the private sector to get it done. Here are the engineering challenges behind key elements of the telescope.

Mirror

In order to see distant objects, JWST needs a big mirror. Blake Marie Bullock, the campaign lead on JWST at Northrup Grumman Corporation, explains the need for a big mirror this way: If you leave a coffee can out overnight in a storm, in the morning, the water in the can will be two inches deep. If you leave out a kiddie pool in the same scenario, the pool will also have water two inches deep—but there will be a lot more water in it. In a telescope, “the same thing is happening with photons,” Bullock says. “If you have a bigger bucket, you can have more photons, and see fainter objects.”

This mirror is so big that it won’t fit in a traditional rocket (Webb will go up in one of the European Space Agency’s Ariane 5 rockets), so engineers had to create a mirror that will fold. “There are 18 hexagons, but three of the hexagons [on each side] are folded down like leaves on a dining room table when it’s stowed,” Bullock says. Once in space, the telescope “unfolds like a flower. Figuring out how this process works takes a lot of engineering.”

Even more complicated is figuring out the prescription. “As you’re manufacturing that mirror on the surface of the Earth, gravity pulls it down and bends that structure,” Bullock says. But when the mirrors are up in space, the gravity is gone—so on Earth, the prescription actually has to be perfectly wrong so that it will be right once the telescope goes into space. As you can imagine, it takes a lot of calculations.

In order to be as precise as the mission requires, JWST’s mirrors have to be very, very smooth. So smooth, Bullock says, that “if you took one of these hexagons and stretched it out to the size of the state of Texas, the biggest bump would be 1 centimeter tall.”

Hot vs. Cold

Infrared is sort of like heat, Bullock says, and because JWST is looking for heat, it doesn’t want to see heat. So engineers are building a five-layer, 80-foot long sun shield that will take photons away from the telescope’s eyes, which much be cold to function. And because there’s such a huge difference in temperature between the hot side of the observatory, where temperatures will reach 185 degrees Fahrenheit, and the cold side, which will be a chilly -388 degrees Fahrenheit, engineers have to think about things like how glue and other materials might behave. Engineers also have to wrestle with how to handle things like the sun shield so that it doesn’t have any creases once it’s deployed.

Weight

The bigger something is, the heavier it is—and the more difficult it is to get it out of Earth’s orbit. JWST is no exception. “As the telescopes get bigger, engineers have to think about how to make it light enough to get into space,” Bullock says. Hubble is just a couple of hundred miles above Earth’s surface, but Webb will be a million miles away, where it is both dark—to make imaging planets and stars easier—and cold (so the telescope functions properly).

Testing

No facility is big enough to test Webb in its entirety, so its components are being tested at Johnson Space Center in Houston, Texas. The facility’s cryogenic chamber, according to Bullock, hasn’t been used since the Apollo missions, so it’s been retrofitted to test JWST’s components. The gold-coated mirrors are being tested six at a time, but the chamber isn’t big enough for the 80-foot sun shield. “That means a lot more math to make sure everything will work the first time,” Bullock says.

Given all of these challenges, how can scientists be sure JWST will work? Nothing is 100 percent, but engineers are working hard to make it happen. “Every piece is tested incrementally, verified, put into a larger system and tested again,” Bullock says. “We’ll spend two years testing it to make sure that it works.”

nextArticle.image_alt|e
Frederick M. Brown, Getty Images
arrow
Space
Stephen Hawking’s Memorial Will Beam His Words Toward the Nearest Black Hole
Frederick M. Brown, Getty Images
Frederick M. Brown, Getty Images

An upcoming memorial for Stephen Hawking is going to be out of this world. The late physicist’s words, set to music, will be broadcast by satellite toward the nearest black hole during a June 15 service in the UK, the BBC reports.

During his lifetime, Hawking signed up to travel to space on Richard Branson’s Virgin Galactic spaceship, but he died before he ever got the chance. (He passed away in March.) Hawking’s daughter Lucy told the BBC that the memorial's musical tribute is a “beautiful and symbolic gesture that creates a link between our father's presence on this planet, his wish to go into space, and his explorations of the universe in his mind.” She described it as "a message of peace and hope, about unity and the need for us to live together in harmony on this planet."

Titled “The Stephen Hawking Tribute,” the music was written by Greek composer Vangelis, who created the scores for Blade Runner and Chariots of Fire. It will play while Hawking’s ashes are interred at Westminster Abbey, near where Isaac Newton and Charles Darwin are buried, according to Cambridge News. After the service, the piece will be beamed into space from the European Space Agency’s Cebreros Station in Spain. The target is a black hole called 1A 0620-00, “which lives in a binary system with a fairly ordinary orange dwarf star,” according to Lucy Hawking.

Hawking wasn't the first person to predict the existence of black holes (Albert Einstein's general theory of relativity accounted for them back in the early 1900s), but he spoke at length about them throughout his career and devised mathematical theorems that gave credence to their existence in the universe.

Actor Benedict Cumberbatch, a friend of the Hawking family who portrayed the late scientist in the BBC film Hawking, will speak at the service. In addition to Hawking's close friends and family, British astronaut Tim Peake and several local students with disabilities have also been invited to attend.

[h/t BBC]

nextArticle.image_alt|e
IKEA
arrow
Design
IKEA's New Collection for Tiny Apartments Is Inspired by Life on Mars
IKEA
IKEA

Living in a city apartment can feel claustrophobic at times. As Co.Design reports, the Swedish furniture brand IKEA took this experience to the extreme when designers visited a simulated Mars habitat as research for their latest line of housewares aimed at urbanites.

The new collection, called Rumtid, is tailored to fit the cramped spaces that many people are forced to settle for when apartment-hunting in dense, expensive cities. The designers knew they wanted to prioritize efficiency and functionality with their new project, and Mars research provided the perfect inspiration.

At NASA's Mars Desert Research Station in Utah, scientists are figuring out how to meet the needs of potential Mars astronauts with very limited resources. Materials have to be light, so that they require as little rocket fuel as possible to ferry them to the red planet, and should ideally run on renewable energy.

IKEA's designers aren't facing quite as many challenges, but spending a few days at the simulated Martian habitat in Utah got them thinking on the right track. The team also conducted additional research at the famously snug capsule hotels in Tokyo. The Rumtid products they came up with include an indoor terrarium shaped like a space-age rocket, a set of colorful, compact air purifiers, and light-weight joints and bars that can be snapped into modular furniture.

The collection isn't ready to hit IKEA shelves just yet—the chain plans to make Rumtid available for customers by 2020. In the meantime, the designers hope to experiment with additional science fiction-worthy ideas, including curtains that clean the air around them.

Air purifiers designed for urban living.

Furniture joints on bubble wrap on black table.

Modular furniture holding water bag.

[h/t Co.Design]

All images courtesy of IKEA.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios