NASA delays tightening James Webb Space Telescope sunshield to study power system
The Webb space telescope, which launched on Dec. 25, is in the midst of a month-long deployment process to prepare it for data collection. However, the majority of the phases in that procedure are managed from the ground: While NASA has a tentative schedule for the work, mission officials can opt to change it as the project progresses. After taking Saturday (Jan. 1) off, the Webb team will analyse the observatory's power component on Sunday (Jan. 2), NASA stated.
"Nothing we can learn from simulations on the ground compares to evaluating the observatory once it's up and operating," said Bill Ochs, Webb project manager at NASA's Goddard Space Flight Center in Maryland, in a statement released Sunday (Jan. 2). "Now is the instant to learn all we can about the company's fundamental operations. Then we'll go to the following phase."
The temperature of a set of motors that will be employed during sunshield tensioning, the procedure that separates and smooths the five fragile layers of the kite-shaped sun deflector, is of special interest to the team. (Because Webb specialises in infrared studies, which are heat sensitive, the sunshield is an essential part of the observatory.)
In the same release, Mike Menzel, Webb's lead systems engineer at GSFC, said, "We've spent 20 years on the ground with Webb, designing, developing, and testing." "We've got a week to see how the observatory performs in space. Once you're in orbit, it's pretty uncommon to pick up on some of your spacecraft's characteristics. That is accurately what we are doing at the instant. So far, the big deployments we've carried out have gone according to plan.
The sunshield tensioning is a time-consuming procedure that NASA estimates will take two days. NASA had planned to begin work on Saturday, but Friday's operations took longer than expected, so the team decided to rest on New Year's Day.
When mission managers chose to look at the motor temperatures more closely, they didn't want the team to be working on two different parts of the observatory at the same time.
The team will deploy the secondary mirror after the sunshield has been properly tensioned.
Despite the fact that deployment has come to a halt, the observatory is still moving forward. Webb was more than 510,000 miles (825,000 kilometres) away from Earth as of just before 3 p.m. EST (2000 GMT), or 57 percent of the way to its final destination of the Earth-sun Lagrange point 2. In the opposite direction from the sun, that point, also known as L2, is about 1 million miles (1.6 million kilometres) away from Earth.
At 7:20 a.m. EST (1220 GMT; 9:20 a.m. local time in Kourou), an Ariane 5 rocket launched from Europe's Spaceport in Kourou, French Guiana, carrying the highly anticipated, long-delayed James Webb Space Telescope — and the hopes and thoughts of innumerable astronomers, astrophysicists, and planetary scientists around the world — into the final frontier.
If all goes according to strategy, the huge telescope will stare at the universe's initial stars and galaxies, sniff the atmospheres of nearby alien planets, and do a variety of other high-profile, high-impact work during the next five to ten years.
The space telescope flew into an overcast sky over Kourou before disengaging from its Arianespace-built rocket approximately a half-hour later. As live views of Webb floating away and deploying its solar array reached Earth, cheers erupted at launch control.
On NASA's live transmission, an Arianespace flight controller cheered, "Go, Webb, go!"
Related: How the James Webb Space Telescope works in pictures
NASA Administrator Bill Nelson told Space.com last week that the mission is "one-of-a-kind." "It is the most advanced technology that, if successful, will reveal mysteries of the cosmos that are really astounding, if not almost overwhelming, [giving a] quantum jump in comprehension of who we are, how we got here, what we are, and how it all evolved."
Every mission must include the phrase "if successful." It seems especially important to emphasise with Webb, considering the observatory's colossal importance and complexity.
Webb is "by far the most complex thing NASA has ever done," according to Jonathan Gardner, Deputy Senior Project Scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It's perhaps the largest pure science struggle ever started by United States."
Webb has been in development for about three decades. The discussion began in September 1989 at the Space Telescope Science Institute in Baltimore, when a group of astronomers met to consider a possible successor to the Hubble Space Telescope.
Hubble hadn't even launched yet, but because large space telescopes take a long time to plan and build, astronomers like to plan ahead a decade or two. And, in this case, there was a strong desire to avoid a large observation gap between Hubble and the replacement, dubbed the "Next Generation Space Telescope" (NGST) informally.
Hubble was successfully launched into Earth orbit in April 1990, but it was clear from away that something was wrong: the scope's first photos were frustratingly fuzzy. According to Robert Smith, a history professor at the University of Alberta in Canada who has written extensively about Hubble and other astronomy missions, this unanticipated development had a chilling effect on NGST planning.
"Things really [weren't] advancing very much as a result," Smith said during a presentation to NASA's Future In-Space Operations working group last week, referring to the NGST's current condition. "Fixing Hubble was the top priority."
In December 1993, spacewalking astronauts corrected a fault in Hubble's 7.9-foot-wide (2.4-meter) primary mirror by installing corrective optics and replacement equipment. According to Smith, the repair permitted NGST work to resume, but more than three years of planning time had been lost, or at the very least jeopardised.
By the mid-1990s, it had become clear that the NGST should focus on the early universe. Hubble has already supplied views of the cosmos one billion years after the Big Bang (13.8 billion years ago), according to Gardner. But astronomers intended to delve further deeper — ideally, all the way back to the birth of the universe's first stars and galaxies, which most likely formed within the first few hundred million years.
Related: Building the James Webb Space Telescope (gallery)
Because of this primary goal, the new telescope has to be designed to collect and analyse infrared light, which we perceive as heat — a significant change from Hubble, which primarily observes optical and ultraviolet (UV) wavelengths. After all, the early stars and galaxies' optical and UV emissions have been stretched so far by the universe's continuous expansion that we can now detect them at longer infrared wavelengths. Infrared light also travels faster than its higher-energy cousins, allowing it to pass through the clouds of dust and gas that litter the universe.
To collect enough deep-space photons to investigate, the new observatory would have to be quite large. The initial design called for a primary mirror that was at least 13.2 feet (4 metres) in diameter. The NGST team was pushed to think bigger by then-NASA chief Daniel Goldin, and a 26.4-foot-wide (8 m) mirror was soon added to the plan.
According to Smith, the NGST's core architecture was nearly complete by 1996. Researchers predicted at the time that the powerful observatory would cost around $1 billion and might launch as early as 2007. We can clearly see that such statistics were far too optimistic.
Even though the observatory's scope had been reduced slightly, the anticipated cost had risen to roughly $5 billion by 2010, and the planned launch had been pushed back to 2014. (Its mirror diameter had been reduced from 6 m to 6.5 m, or 19.7 feet to 21.3 feet.) There was growing worry that the mission's ever-increasing appetite — which was officially named after Apollo-era NASA chief James Webb in September 2002 — might starve other NASA astrophysics programmes, a feeling expressed in a 2010 Nature storey titled "The telescope that ate astronomy."
In July 2011, the House Appropriations Committee considered terminating Webb's appointment. Scientists and powerful politicians, including then-US Senator Barbara Mikulski (D-Maryland), battled to save the project, and it was saved a few months later.
References: https://www.space.com/james-webb-space-telescope-sunshield-deployment-success
https://www.space.com/james-webb-space-telescope-sunshield-tension-delay
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