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NASA resumes Webb deployments after pausing for weekend

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The James Webb Space Telescope’s five-layer sunshield, seen here during ground testing at Northrop Grumman’s factory in Redondo Beach, California. Credit: NASA/Chris Gunn

Mission controllers started the delicate work of tightening the five razor-thin layers of the James Webb Space Telescope’s sunshade Monday. Managers said the nearly $10 billion observatory is “hunky-dory” after pausing deployments over the weekend to adjust the observatory’s power levels and ensure motors needed for the tensioning are in tip-top shape.

Ground teams at the Space Telescope Science Institute in Baltimore, Maryland, hoped to complete tensioning of the largest and hottest layer of the tennis court-sized sunshield Monday. The remaining four will be pulled taut with a complex system of electric motors, pulleys, and cables Tuesday and Wednesday, assuming everything goes according to plan, said Bill Ochs, NASA’s Webb project manager.

But managers have flexibility in the schedule, and there’s no rush to push Webb through its remaining deployments, a sequence of events required to transform Webb from its launch configuration into a telescope tuned to register the faint infrared light from the first galaxies in the universe.

“We do not want to burn out our team along the way,” Ochs said Monday in a conference call with reporters.

The first week of Webb’s mission went like clockwork, but engineers changed the schedule over the weekend to make adjustments to the spacecraft’s power-generating solar array and cool higher-than-expected temperatures on the motors required to pull the sunshade tight.

One of the reasons officials put off tensioning the sunshield was to give ground teams time to “rebalance” Webb’s 20-foot-long (6-meter) solar array to improve its power generating capacity. The change involved adjusting the solar array, made of five individual panels, off its factory settings, according to Amy Lo, a Webb systems engineer at Northrop Grumman, NASA’s prime contractor for the mission.

The solar array was generating enough electricity for Webb, but engineers prefer as much power margin as possible, especially as the power-hungry observatory continues through more deployments and commissioning.

Lo said engineers knew they would reset the array’s operating parameters after monitoring its performance in space. The power throughout from the solar array can depend on a range of factors, including the temperature of the system’s solar cells and regulators feeding power to Webb’s batteries. A hotter solar panel is slightly less efficient at generating power than a cooler panel, Lo said.

“The factory preset makes all of the panels and all of the regulators operate at the same duty cycle (or operating regime), so it’s not very optimized,” Lo said Monday.

“As we got on orbit and understood what temperatures the arrays were operating at, and tracked the load we expected to see, we then went ahead and made the decision that we did want to rebalance the array and set a duty cycle so that each panel of the array … could be optimized to work at their best duty cycle possible.”

The reset Sunday changed the system’s voltage from 58.6 volts to between 65 and 69 volts, Lo said.

“So the change wasn’t much, but it’s what we needed,” Lo said. “Everything is hunky-dory and doing well now. The observatory was never in danger.”

Artist’s concept of the James Webb Space Telescope, as it appeared after opening the mission’s five-layer sunshield. Credit: NASA

The other technical issue Webb’s ground team addressed over the weekend was with the sunshade tensioning motors.

The motors are critical components needed to drive the sunshade layers to their fully tensioned state. Their temperatures were a bit warmer than expected over the weekend, but still within operating limits.

“As we looked at the temperature of the motors, it did not have as much margin as we preferred,” Lo said Monday. “One way of cooling the motor is to re-point the observatory, so there’s less incident sun on these motors, so they can have time too cool off. So that was executed last night.”

The Webb telescope launched Dec. 25 aboard a European Ariane 5 rocket, and has performed well as it unfolded its solar array, high-gain communications antenna, and two large pallet structures that held the sunshade layers for the ride to space.

Webb extended a tower assembly last week to provide distance between the telescope’s mirrors and instruments, which must be chilled to cryogenic temperatures, and the much hotter spacecraft, with the solar array that needs to be constantly pointed at the sun.

The sunshield is designed to provide a nearly 600-degree thermal gradient between the hot spacecraft and the cold telescope. It has five layers, each as thin as a human hair, made of a material called kapton and treated with shiny aluminum. The two outermost layers have an additional purple-hued silicon coating to aid in reflectivity.

Ground teams uplinked commands for Webb to roll off covers to reveal the sunshield membranes Thursday, then extended two mid-booms out each side of the spacecraft Friday, pulling out the five sunshade layers like sheets on a bed.

“Mid-boom deployment was huge,” Ochs said. “That was really a huge achievement for us. The tensioning of the layers is the next big step that we go through.”

Before Webb’s launch, most NASA managers and astronomers gave the same answer about the most stressful moment of the mission: Sunshield deployment.

“The sunshield is one of these things that is almost inherently indeterministic,” said Mike Menzel, Webb’s mission systems engineer at NASA’s Goddard Space Flight Center in Maryland, in a press conference before launch. “NASA is used to deploying rigid beams on hinges, because they’re deterministic, you can determine how they move.”

“Given that there are 40 different major deployments, and hundreds of pulleys and wires, the whole thing makes me nervous and will until its fully deployed,” said John Grunsfeld, an astrophysicist, former astronaut, and head of NASA’s science mission directorate from 2012 until 2016, a key period in Webb’s development.

Menzel compared predicting the behavior of the sunshield layers to guessing what a string will do when you push it on a table top.

“So it is with the membranes of the sunshield,” he said. “So we can’t really predict their shape, but we can constrain it. “We can try to prevent it from going in places that we don’t want it to go, places where it could snag or tear, or maybe impede the deployment of other members.”

Each layer of the sunshield is slightly different in size and shape, created using thermally bonded sections of kapton with around 10,000 seams, according to Krystal Puga, Webb’s lead spacecraft systems engineer at Northrop Grumman.

There are reinforcement strips, or rip stops, to contain any tears or holes, and metallic ribbons giving the kapton some structural support.

“Once we get the sunshield out, that’s great, but then we have to sort of tighten it up,” said Keith Parrish, NASA’s commissioning manager for Webb, in an interview before launch. “All five layers have different points around them where they’re connected up, and then we’ll pull on cables in each one of those corners to actually tighten up the sunshield.”

“The very last step is super important,” Puga said. “We need to tension all of the membranes using a series of pulleys and cables to create the separation between each of the five layers.”

The tensioning will separate each of the five ultra-thin membranes, spacing them a few inches at the center and a few feet at the outermost edges. The tapered spacing helps allow heat from the sun to reflect between the layers, and eventually radiate back into space.

Six motors will pull on a quarter-mile of cable on the left and right side of the sunshield, and at the front and back, to tighten up the five kapton layers. If the motors get too hot, teams can send commands for Webb to halt the motion.

“JWST deployment is designed to stop any any point,” Lo said. “We can stop at any time and do a little bit of reverse, and then keep going. That is a basic fundamental design driver that we have in our requirements.”

The movement will be slow, with guides to help make sure there are no snags or tears. The deployment of the mid-booms Friday worked exactly as designed, with 107 critical release mechanisms activating to allow the solar blanket to unfurl.

“The observatory is designed very carefully to be snag-free, and we have tested this multiple times on the ground,” Lo said. “Given that our telemetry matches the ground testing, we are expecting to have smooth sailing.”

Ochs said once all five sunshade layers are fully tensioned, the mission will have “retired somewhere between 70 and 75%” of the 344 single-point failures identified before launch. Those 344 potential failure points cover critical devices and components, without backups, that have to work for Webb to complete its mission.

Webb’s instruments and telescope need to be super-cold to make them sensitive to infrared light. And astronomers want to observe the cosmos in infrared wavelengths because it allows them to see the oldest galaxies, whose light waves have been stretched by the expansion of the universe.

Infrared astronomy also reveals star-forming regions obscured by clouds of gas and dust opaque to telescopes that see in visible wavelengths, the kind of light detectable by the human eye.

Mark McCaughrean, an astronomer at the European Space Agency, tweeted last week that infrared astronomy with a warm telescope “is like trying to observe in the visible in broad daylight with a telescope made of light bulbs. Possible, but you won’t see faint things very well.”

Once the sunshield is deployed and tensioned, ground teams will turn their attention to unfolding Webb’s huge primary mirror to its full 21.3-foot-wide (6.5-meter) diameter, the biggest telescope ever sent into space. A secondary mirror, mounted on a tripod-like boom apparatus, also needs to move into place to reflect light into Webb’s instrument module, and ultimately onto detector arrays to make images and spectral measurements.

Those events are scheduled to begin at the end of this week, Ochs said, a few days later than originally planned after the pause in deployments over the weekend.

Webb is cruising toward its operations post in a halo-like orbit around the L2 Lagrange point, a gravitational balance point nearly a million miles (1.5 million kilometers) from Earth. Webb’s arrival in that orbit is expected around Jan. 23, followed by five more months of instrument activations, optical focusing, and other calibration work before the science mission begins.

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First Chinese space mission of 2022 rockets into orbit

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A Chinese Long March 2D rocket lifts off with the Shiyan 13 satellite. Credit: CASC

China launched a Long March 2D rocket Monday with another classified satellite, deploying the spacecraft into a polar orbit on the first of more than 40 Chinese Long March rocket missions planned in 2022.

The Long March 2D rocket took off from the Taiyuan launch base in Shanxi province of northern China at 0435 GMT Sunday (11:35 p.m. EST Sunday), according to the China Aerospace Science and Technology Corp. or CASC.

Liftoff occurred at 10:35 a.m. Beijing time Monday.

CASC, China’s largest state-owned space industry contractor, said the Long March 2D rocket delivered the Shiyan 13 satellite into orbit. Chinese officials did not disclose details about the purpose of the mission, other than claiming Shiyan 13 will be used for space environment data collection and technology tests.

China’s series of Shiyan satellites, which began launching in 2004, have been used for technology demonstrations and experiments. Many of the Shiyan missions to date have likely had a military purpose.

The 134-foot-tall (41-meter) Long March 2D rocket that carried Shiyan 13 into orbit lifted off with more than 650,000 pounds of thrust from its hydrazine-fueled first stage engines. Heading south from Taiyuan over Chinese territory, the two-stage launcher climbed through the atmosphere accelerated to a speed of nearly 5 miles (8 kilometers) per second.

The U.S. military, which publishes orbital data online, said it tracked the Shiyan 13 satellite in an orbit between 287 miles and 309 miles (463 by 498 kilometers) at an inclination of 97.4 degrees to the equator.

Chinese officials declared the launch a success, and the U.S. military tracking data confirmed the mission reached orbit.

CASC said in a statement that the launch was the first of more than 40 missions the organization plans to perform this year. CASC builds and oversees the Long March rocket family, China’s most-flown launch vehicle.

More than 15 of the launches will use the Long March 2D rocket configuration, according to CASC. The Long March 2D is designed to carry payloads weighing up to 2,900 pounds (about 1.3 metric tons) into a polar sun-synchronous orbit.

Accomplishing 15 or more Long March 2D launches this year would set an annual record for this type of rocket.

Other major Chinese space missions scheduled for launch in 2022 include six Long March rocket flights to build and outfit China’s space station.

The station’s Tianhe core module launched last April on a heavy-lift Long March 5B rocket. China launched a Long March 7 rocket with a Tianzhou cargo ship in May to dock with the Tianhe module, delivering supplies for first three astronauts who launched to the station in June.

That crew returned to Earth in September, the same month China launched another Tianzhou cargo mission.

Three more astronauts on China’s Shenzhou 13 spacecraft launched and docked with the station’s Tianhe core module in October to begin a six-month stay, the longest China human spaceflight mission to date.

This year, China aims to launch two more large space station modules — each weighing more than 20 tons at launch — on Long March 5B rockets from the Wenchang space center on Hainan Island. The Wentian and Mengtian pressurized modules will adding living space and scientific laboratory capabilities to the Chinese space station.

Two Tianzhou cargo freighters on Long March 7 rockets and two Shenzhou crew ferry ships on Long March 2F rockets are also scheduled to launch to the Chinese space station this year.

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Live coverage: SpaceX plans prime time launch of Falcon 9 rocket Monday night

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Live coverage of the countdown and launch of a SpaceX Falcon 9 rocket from pad 39A at NASA’s Kennedy Space Center in Florida. The mission will launch SpaceX’s next batch of 49 Starlink broadband satellites. Text updates will appear automatically below. Follow us on Twitter.

SFN Live

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Keeping up a rapid-fire launch cadence to begin 2022, SpaceX is gearing up to launch another Falcon 9 rocket Monday night from Kennedy Space Center in Florida with 49 Starlink internet satellites.

Liftoff from pad 39A is set for 7:26 p.m. EST Monday (0026 GMT Tuesday) to kick off a 15-minute launch sequence before deploying the 49 flat-panel Starlink satellites into orbit.

You can watch our live launch coverage on this page.

The 229-foot-tall Falcon 9 rocket will head southeast from Kennedy Space Center to deploy the Starlink payloads into an orbit inclined 53.2 degrees to the equator. The mission will aim to release the Starlink satellites at T+plus 15 minutes, 32 seconds, into an orbit ranging in altitude between 130 miles and 210 miles (210 by 339 kilometers).

This mission, designated Starlink 4-6, is SpaceX’s third Falcon 9 launch of the year. The first stage booster, tail number B1060, will be making its 10th trip to space and back.

SpaceX’s drone ship “A Shortfall of Gravitas” is on station in the Atlantic Ocean north of the Bahamas for landing of the first stage booster.

Read our mission preview story for details.

ROCKET: Falcon 9 (B1060.10)

PAYLOAD: 49 Starlink satelllites (Starlink 4-6)

LAUNCH SITE: LC-39A, Kennedy Space Center, Florida

LAUNCH DATE: Jan. 17, 2022

LAUNCH TIME: 7:26 p.m. EST (0026 GMT on Jan. 18)

WEATHER FORECAST: 80% probability of acceptable weather

BOOSTER RECOVERY: “A Shortfall of Gravitas” drone ship north of the Bahamas

LAUNCH AZIMUTH: Southeast

TARGET ORBIT: 210 miles by 130 miles (339 kilometers by 210 kilometers), 53.2 degrees inclination

LAUNCH TIMELINE:

  • T+00:00: Liftoff
  • T+01:12: Maximum aerodynamic pressure (Max-Q)
  • T+02:32: First stage main engine cutoff (MECO)
  • T+02:35: Stage separation
  • T+02:42: Second stage engine ignition
  • T+02:52: Fairing jettison
  • T+06:47: First stage entry burn ignition (three engines)
  • T+07:07: First stage entry burn cutoff
  • T+08:25: First stage landing burn ignition (one engine)
  • T+08:47: First stage landing
  • T+08:50: Second stage engine cutoff (SECO 1)
  • T+15:32: Starlink satellite separation

MISSION STATS:

  • 137th launch of a Falcon 9 rocket since 2010
  • 145th launch of Falcon rocket family since 2006
  • 10th launch of Falcon 9 booster B1060
  • 121st Falcon 9 launch from Florida’s Space Coast
  • 137th launch overall from pad 39A
  • 43rd SpaceX launch overall from pad 39A
  • 81st flight of a reused Falcon 9 booster
  • 35th dedicated Falcon 9 launch with Starlink satellites
  • 3rd Falcon 9 launch of 2022
  • 3rd launch by SpaceX in 2022
  • 3rd orbital launch based out of Cape Canaveral in 2022

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Cape Canaveral’s busy January to continue with another Starlink launch

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File photo of a Faclcon 9 rocket on pad 39A at NASA’s Kennedy Space Center. Credit: Stephen Clark/Spaceflight Now

Forecasters expect brisk winds and chilly temperatures for a prime time, full moon launch of a SpaceX Falcon 9 rocket with another batch of Starlink internet satellites Monday night from NASA’s Kennedy Space Center in Florida.

There’s a 70 percent chance of good conditions for launch at 7:26 p.m. EST Monday (0026 GMT), according to a forecast issued Saturday morning by the U.S. Space Force’s 45th Weather Squadron. There’s a backup instantaneous launch opportunity at 9:24 p.m. EST (0224 GMT).

The mission, designated Starlink 4-6, will carry around 49 Starlink internet satellites into orbit for SpaceX’s global internet network. The Falcon 9 is expected to fly southeast from pad 39A at Kennedy Space Center, heading over the Atlantic Ocean just north of the Bahamas before making a slight right-hand turn to line up with the target orbital plane for deployment of the Starlink payloads.

The flight profile is expected to match that of the most recent Starlink launch Jan. 6, which was the first Starlink mission from Florida to head southeast, rather than northeast. That mission carried 49 flat-panel Starlink satellites into space. SpaceX hasn’t announced yet how many Starlink satellites are on Monday’s launch, but it’s expected to be a similar number.

Launch trajectories from Cape Canaveral have historically tracked east or northeast over the Atlantic Ocean.

But SpaceX, with approval from the Space Force’s Eastern Range, has opened new launch trajectories in recent years. Falcon 9 missions have also flown south along the Florida coastline to reach polar orbit, a destination that was inaccessible from Cape Canaveral for 50 years.

U.S. launches into polar orbit have typically departed from Vandenberg Space Force Base in California, which has an open range of ocean to the south of the spaceport.

The south and southeast launch paths from Cape Canaveral require rockets to perform turns, or “dog-leg” maneuvers, using some of their performance to fly around land masses and populated areas. That reduces the number of Starlink satellites SpaceX can launch on a single mission, but the company has said it intends to use the southeast launch trajectories in winter months to improve the chances of good offshore conditions for landing of the Falcon 9’s first stage booster.

For this mission, like the last Starlink launch, SpaceX’s drone ship will be parked north of the Abacos Islands in the Bahamas. For launches to the northeast, the landing platform is positioned east of Charleston, South Carolina, a region that sees rougher seas and higher winds in the winter.

A stack of Starlink satellites awaiting encapsulation inside the payload fairing before a previous Falcon 9 launch. Credit: SpaceX

SpaceX will surpass the 2,000-satellite mark in its Starlink program with Monday night’s launch. Roughly 200 of those satellites have failed or been decommissioned by SpaceX’s ground control team, according to a tabulation maintained by Jonathan McDowell, an astrophysicist and respected tracker of global spaceflight activity.

The Starlink 4-6 mission will be SpaceX’s 35th dedicated launch since May 2019 for the Starlink program.

SpaceX has a long-term plan to launch as many as 42,000 Starlink satellites, according to a company filing with the International Telecommunication Union. The company’s initial focus is on deploying thousands of satellites into five orbital “shells.”

The 53.2-degree inclination shell, the target for Monday night’s launch is one of the five orbital shells at different inclination angles that SpaceX plans to fill with around 4,400 satellites to provide high-speed, low-latency broadband connectivity around the world. The first shell, at 53.0 degrees, was filled with its full complement of satellites last May.

As of last week, SpaceX said the Starlink network is now live in 25 countries and regions, serving more than 145,000 users worldwide. SpaceX builds its Starlink satellites on an assembly line in Redmond, Washington, and the company is developing and iterating its own user terminals.

SpaceX hopes to use revenue from the Starlink business unit to help fund the company’s ambitions to complete development of the heavy-lift Starship rocket, a massive fully reusable launcher designed to eventually replace the Falcon 9 and Falcon Heavy rockets.

On Monday night’s mission, the Falcon 9 rocket is expected to target an orbit a couple hundred miles above Earth. After flying free of the launch vehicle, the 49 Starlink satellites — each about a quarter-ton in mass — will unfurl solar panels and use ion thrusters to climb to an operational altitude of 335 miles (540 kilometers).

The forecast for Monday night calls for a mostly clear sky and gusty west winds of 20 to 25 mph. The temperature at launch times is forecast to be around 52 degrees Fahrenheit.

Rainy weather is expected along the Space Coast Sunday, but the weather system will push through the region in time for Monday evening’s launch opportunity, according to the Space Force weather team.

“Clouds will diminish through the day Monday at the spaceport, leaving gusty winds as the primary launch weather threat,” the forecaster team wrote. “On Tuesday, high pressure will settle overhead making for a chilly morning, but excellent launch weather conditions.”

The launch will continue a busy January at the Florida spaceport, with seven rocket launches scheduled on the Eastern Range. Two of the missions, both by SpaceX, are already in the books, with five more on tap before the end of the month, including Monday’s Falcon 9 flight.

A small satellite launcher developed by Astra is slated to take off as soon as next week from the Complex 46 launch pad at Cape Canaveral, carrying several CubeSats into orbit on a demonstration flight for NASA.

United Launch Alliance’s first mission of 2022 is scheduled for Friday, Jan. 21, with a pair of Space Force surveillance satellites heading to geostationary orbit.

Two more SpaceX launches are scheduled for the last week of January from each of the company’s Florida launch pads.

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