الجمعة، 16 ديسمبر 2022

This Week in Space: Trouble From Launchpad to LEO

The Apollo 17 lunar rover. (Credit: NASA/Gene Cernan, via NASA HQ)
Hello, readers, and welcome back. This week in space, there’s trouble, from here to there and back again. NASA and Roscosmos are scrambling to stabilize a coolant leak from the Soyuz capsule docked at the International Space Station. But it’s not all bad news; Orion splashed down safely over the weekend. This week we celebrate the 50th anniversary of Apollo 17, humanity’s last crewed mission to the moon — at least, for a while yet. Astronomers working with the Hubble telescope found two gigantic “water worlds.” And this week’s astronomy image from the JWST shows a sky strewn with cosmic PEARLS. We’ll wrap up with a word on the Geminid meteor shower.

Orion Splashes Down Safely, 50 Years After Apollo 17

Sunday afternoon, the Orion spacecraft splashed down safely, following a nearly perfect 25-day mission. And its timing could scarcely have been better. This week marked the 50-year anniversary of Apollo 17, the last time we put people on the moon.

(Credit: NASA)

(Credit: NASA)

After stepping out of the Challenger Lunar Module, Apollo 17 astronaut Harrison “Jack” Schmitt said, “I think the next generation ought to accept this as a challenge. Let’s see them leave footprints like these.” Schmitt recently sat down with NASA’s “Houston We Have a Podcast” to talk about the mission — and what we’re still learning from the 850 pounds of moon rocks that the Apollo astronauts brought home years ago.

“The cores that we took on Apollo 17, particularly the deep drill core as it’s called, appears now to have a record of a major change in solar activity and the energy coming into the solar wind about 550 million years ago,” Schmitt told the podcast. Evidence from lunar regolith suggests that the Sun’s highest-energy blasts of radiation may have dropped off, right around that time. When it did, the idea goes, ionizing radiation stopped sterilizing the tidal shallows that would soon foster the Cambrian explosion.

Schmitt went on to voice his hope that future Artemis astronauts would retrieve new core samples to dig deeper into the question of what the geological history of the moon can tell us about the long-term evolution of the Earth. But, he said, “the current Artemis program is not without its challenges; Apollo didn’t solve all those challenges. We had a different approach at the time and an approach that worked. And Artemis needs to make sure that they’re coming up with an architecture, as they like to say, that actually will work.”

Hubble Finds Gigantic ‘Water Worlds’

Astronomers using the Hubble telescope have located two rocky exoplanets that are not as they seem. The planets are twice the size of Earth, and three times its mass. But their density and spectra suggest that they’re too light to be all rock. Instead, the researchers believe the two planets to be “water worlds.”

“Imagine larger versions of Europa or Enceladus, the water-rich moons orbiting Jupiter and Saturn, but brought much closer to their star,” explained astronomer Caroline Piaulet, who led the research. “Instead of an icy surface, they would harbor large water-vapor envelopes.”

In this illustration the super-Earth, Kepler-138d is in the foreground. To the left, the planet Kepler-138c, and in the background the planet Kepler 138b, seen in silhouette transiting its central star. Kepler 138 is a red dwarf star located 218 light-years away. The low density of Kepler-138c and Kepler-138d — which are nearly identical in size — means that they must be composed largely of water. They are both twice Earth’s mass but have roughly half of Earth’s density, and therefore cannot be solid rock. This is based on measurements of their mass vs. physical diameter. They are considered a new class of “water-planet,” unlike any major planet found in our solar system. Kepler-138 b is one of the smallest exoplanets known, having the mass of the planet Mars and the density of rock. [Image Description: Illustration of three planets and their star on the black background of space speckled with dots of different colors. The planets are various sizes, indicating different distances from the viewer and from the star. The largest, foreground planet, is at the upper right, and is grayish white with bands of clouds.]

Artist’s illustration of the Kepler 138 planetary system. (Credit: NASA, ESA, L. Hustak (STScI))

“We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that’s why we called them super-Earths,” said Björn Benneke, who heads Piaulet’s research lab. “However, we have now shown that these two planets, Kepler-138 c and d, are quite different in nature and that a large fraction of their entire volume is likely composed of water. It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time.”

Water worlds though they might be, these planets may not have surface oceans, like Earth. Instead, Piaulet says, they might more closely resemble the scalding, choking fog on Venus.

“The temperature in Kepler-138 d’s atmosphere is likely above the boiling point of water, and we expect a thick dense atmosphere made of steam on this planet. Only under that steam atmosphere could there potentially be liquid water at high pressure, or even water in another phase that occurs at high pressures called a supercritical fluid,” Piaulet said. The team expects to make follow-up observations using the James Webb Space Telescope in 2023.

James Webb Space Telescope Finds Cosmic PEARLS

This week’s image from the James Webb Space Telescope is a medium-deep-field view of the North Ecliptic Pole. It’s also among the largest images we’ve ever seen. The area is just two percent of the size of the full moon. But in it, we see a sky strewn with galaxies, glittering against the perfect blackness like so many jewels. Fittingly, the image comes from the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) GTO program, which sets aside a portion of the telescope’s time for those involved in its development.

Click to open the image in a new tab. For truly gigantic full-res versions with and without annotations, check out the StSci explainer page — but be careful! At 18,828 by 6,397 pixels, they’re not for the faint of heart. (Credit: NASA)

This seldom-surveyed region of the sky is perpendicular to the ecliptic, the path the Sun appears to trace out on the Earth’s surface over the course of a year. Happily, Webb is in a position that gives it an unobstructed view of that part of the sky. “This unique field is designed to be observable with Webb 365 days per year, so its time-domain legacy, area covered, and depth reached can only get better with time,” said Rogier Windhorst, principal investigator of the PEARLS team.

“I was blown away by the first PEARLS images,” said Rolf Jansen, a PEARLS co-investigator. “Little did I know, when I selected this field near the North Ecliptic Pole, that it would yield such a treasure trove of distant galaxies, and that we would get direct clues about the processes by which galaxies assemble and grow. I can see streams, tails, shells, and halos of stars in their outskirts, the leftovers of their building blocks.”

To create the image, the team combined observations from Webb’s NIRCam near-infrared instrument with spectra from NIRISS, the telescope’s onboard spectrograph. Altogether, when the PEARLS team is finished, they’ll have imaged a swathe of the sky four times this size.

Explosive Coolant Leak From Soyuz Capsule

NASA and Roscosmos are working fast, after a serious coolant leak Wednesday night from the Soyuz MS-22 capsule currently docked at the International Space Station.

In statements Thursday, Roscosmos said that the outer hull of the capsule appears to have been damaged. Out of an abundance of caution, the agency also canceled the Thursday spacewalk it had planned for cosmonauts Dmitri Petelin and Prokopyev. It’s possible that the leak is from an orbital debris strike. However, the capsule’s inner hull is intact, and all the people aboard the space station are fine.

In addition to Petelin and Prokopyev, the station currently hosts cosmonaut Anna Kikina, JAXA astronaut Koichi Wakata, and NASA astronauts Frank Rubio, Josh Cassaa, and Nicole Mann. Nobody was even exposed to the coolant because the crew noticed the leak before the cosmonauts left the station — and both agencies want to keep it that way. In an update on the space station blog, NASA said, “Plans for an additional inspection of the Soyuz exterior using the station’s Canadarm2 robotic arm are underway.”

Cosmonaut Anna Kikina used the robotic Canadarm2 to capture this image of Soyuz after the leak. (Credit: NASA)

Two other Russian resupply ships, Progress 81 and 82, are currently docking with the station. There’s also a Northrop Grumman Cygnus ‘space freighter,’ and two SpaceX capsules (a Cargo and Crew Dragon, respectively).

The MS-22 capsule that sprang the leak carried Petelin, Prokopyev, and Rubio to the ISS on Sept. 21. Neither of the agencies has said how the three will get home if the Soyuz capsule can’t make the trip. MS-23 won’t launch until March. SpaceX might be able to scramble a rocket. However, in 1979, after a similar situation aboard the Salyut 6 Soviet space station, Russia sent up an unpiloted Soyuz capsule that brought two marooned cosmonauts safely home. It’s a sobering reminder that space, the big empty, is a merciless adversary.

One of the Last Three Ariane 5 Rockets Just Launched

Over the weekend, one of the last Ariane 5 rockets was launched from the ESA’s spaceport in French Guiana. Its big-ticket passenger: The first in a fleet of six Meteosat Third Generation Imager satellites. This one, MTG-1, will also be Europe’s first lightning imaging satellite. When the other five join it, they’ll monitor weather across the world from geostationary orbit, about 36,000 km up.

Ariane 5 launches from French Guiana. (Credit: ESA–M. Pedoussaut)

This flight also carried into orbit the Intelsat Galaxy 35 and 36 satellites. These satellites are part of Intelsat’s ongoing effort to clear out the C band of the spectrum, ahead of widespread 5G infrastructure deployment.

Only two Ariane 5 rockets remain, and they’re both spoken for. The last one will carry the ESA’s Jupiter Icy Moons Explorer (JUICE) spacecraft, which will explore Ganymede, Callisto, and Europa. Meanwhile, the ESA is preparing for the maiden flight of the first Ariane 6 heavy-lift vehicle, which it hopes to launch in Q3 2023.

SpaceX Launches One Rocket, Queues Up Two More

Late Thursday evening, NASA officials cleared SpaceX to launch the Falcon 9 rocket that will deploy the agency’s Surface Water and Ocean Topography (SWOT) satellite. The rocket is now due to launch at 3:46 a.m. on Friday morning, from Vandenberg.

In a Wednesday press conference, SpaceX CEO Julianna Scheiman said that the launch slipped from its original date after pre-flight checks discovered problematic levels of moisture in two of the rocket’s nine Merlin engines. The moisture is probably from heavy rains during a test fire last week. If so, said Scheiman, the launch can proceed; otherwise, the company will stand down the rocket for repairs.

The SpaceX Falcon 9 rocket that will launch the SWOT satellite stands ready at Vandenberg. Photo (Credit: NASA/Keegan Barber, via NASA HQ Flickr)

The SWOT satellite is a significant upgrade from its predecessors. Where previous satellites could measure the rough contour of the ocean’s surface, SWOT will use a radio interferometer to extend that ability to rivers and streams.

Two other SpaceX missions may launch between now and tomorrow night, both from Canaveral. Saturday’s launch will deploy the most recent batch of Starlink satellites.

Zhuque-2 Methane Rocket Fails

Despite high hopes for the mission, China’s first commercial methane rocket, Zhuque-2, failed to reach orbit after its Wednesday launch. Shortly after takeoff, the rocket appeared to suffer a sharp decrease in speed and altitude. In statements after the launch, Chinese launch company Landspace said that the rocket’s second stage had failed. Unfortunately, all 14 satellites aboard were destroyed.

China has recently increased and diversified its efforts toward a commercial presence in low-earth orbit. Its state space corporation, CASIC, is funding multiple Chinese domestic launch companies, much like NASA has its Commercial Cargo and Commercial Crew programs. Their projects include research into a wide variety of ways to power a rocket, from kerosene to fusion. Meanwhile, Landspace has another Zhuque-2 rocket in development.

Skywatchers Corner

All through December, you can find winged stallion Pegasus in the evening sky. In Greek myth, Pegasus carried the hero Bellerophon into battle — and later, the thunderbolts of Zeus himself.

Pegasus is the largest of the 88 major constellations, and it’s relatively easy to find. After sunset, look to the southwest for bright Jupiter. About 15 degrees above it, you’ll see the Great Square of Pegasus.

The Geminid meteor shower technically peaked Tuesday night into Wednesday. But if you missed it then, you’ve still got another chance or two. The show will go on until the weekend, dropping off Saturday night.

This shower comes from an asteroid, unlike most meteor showers, which come from comet debris. Asteroid 3200 Phaethon is an unusually active asteroid that actually develops tails like a comet. According to EarthSky.org, Japan’s upcoming DESTINY+ (Demonstration and Experiment of Space Technology for Interplanetary Voyage with Phaethon Flyby and Dust Science) mission t0 3200 Phaethon will launch in 2024.

* * *

It’s the middle of December. That means it’s time for finals week, and then the chaos of the winter holidays. If you’re looking for a gift for a loved one who likes skywatching — or if you have to finally quit dodging texts and get back to your family, who have been badgering you to tell them what you want for Christmas — consider a backyard telescope. You might be stunned at how much telescope you can get for a given price, and they become a treasured pastime and a family heirloom. Binoculars are another good option, and perhaps more flexible. You can use binoculars to get a lovely view of the Moon, and then when the sun comes up, use them for bird-watching.

For a space-themed gift on a tighter budget, there are phone and tablet apps geared toward skywatching. Sky map apps can let you hold your device up to the sky, and give detailed information about the part of the sky in the frame. There are several free and paid options for both Android and iOS, which we discuss here.

Many of you will be traveling next Friday, and so will many of us at ExtremeTech. So, we’ll close with this: However you celebrate, stay safe in your travels. It’s icy all over; if you’re driving, maybe consider tossing a bag of kitty litter in the back before you take off. We’ll see you soon.

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