الجمعة، 9 ديسمبر 2022

This Week in Space: NASA, SpaceX, and the Geminids

Image: NASA

Hello, readers, and welcome back! Today we’ll read that there’s a lot going on at SpaceX, and on Mars. NASA has lost contact with its ICON satellite but reached new heights with Ingenuity. A new analysis of early science images from the James Webb space telescope reveals”‘unseen companions” within the Southern Ring Nebula. Plus, two new ways to power deep space exploration: dynamic soaring and nuclear waste. We’ll wrap up with a few words on this week’s celestial event: the Geminid meteor shower.

Orion Capsule to Splash Down Sunday

On Wednesday (flight day 23) the Orion capsule left the Moon’s gravity well. The capsule has now performed the course correction burns that will turn it homeward. Today (flight day 25), the capsule will take on some of its last remaining milestones, including final inspections for leaks within its propulsion system.

At a Thursday night briefing, NASA officials explained that flight engineers have had the capsule doing “propellant slosh” tests. In these tests, flight controllers fired the capsule’s reaction control thrusters, making the propellant slosh inside its tank. Then, they carefully measured the effect that the sloshing has on Orion’s trajectory and orientation.

During its final approach, Orion will skip on the Earth’s atmosphere, like a rock skipping on water. Meanwhile, NASA will have the recovery crew standing by in a Navy vessel, just a few nautical miles from the splashdown zone. Orion will splash down on the Pacific side of the Baja Peninsula, around 12:40 p.m. EST.

SpaceX to Launch Japanese Moon Lander

While the Orion capsule gathers itself for its final descent, SpaceX will carry a private space company’s moon lander into space. Sunday morning, a Falcon 9 rocket will launch Hakuto-R, a project by Tokyo-based lunar robotics company Ispace. The rocket will also carry a small moon rover from the United Arab Emirates.

The mission has been delayed several times since its original launch date in November. Nevertheless, SpaceX said Wednesday, things are “looking good for launch” on Sunday.

Starlink Wars: The FCC Awakens

The runaway success of SpaceX’s Falcon 9 helped pay for the aerospace company’s megaconstellation of Starlink internet satellites. SpaceX has offered Starlink satellite internet since 2020. However, as more users join the network, congestion is becoming an escalating problem. So, SpaceX announced a 1TB data limit, beyond which users’ bandwidth will be throttled — unless, of course, they’re willing to pay. However, this week, the company amended its schedule, delaying the data cap into February 2023.

The FCC announced this week that SpaceX can launch up to 7,500 of their Starlink v2 satellites — just a quarter of the 30,000-strong fleet for which the company originally applied. In part, the agency said, this is a response to growing concern from astronomers. But it’s also concerned about orbital congestion. The agency approved the v2 Starlink fleet only for specific altitudes.

SpaceX plans to use its Starship launch vehicle, pictured here, to field the Starlink v2 fleet. But the company hasn’t made an orbital test of the rocket yet. (Photo: SpaceX)

Meanwhile, this week SpaceX debuted Starshield, an encrypted Starlink internet service that the company hopes will appeal to governments. Perks include a better version of Starlink’s end-to-end encryption, plus laser communication between Starshield satellites and those that governments already own. Starshield will also support “satellites with sensing payloads,” which my colleague Ryan Whitwam points out probably means “spy satellites.” SpaceX clearly expects the US government to take advantage of the Starshield service. It could also offer the service to other nations — but ITAR might have something to say about that.

Interstellar Travelers Could One Day Glide Like a Seabird

Stand aside, solar sails: A recent study proposes a method of interstellar travel that could use dynamic soaring, plasma magnets, and a “magnetohydrodynamic wing” to push a spacecraft to relativistic speeds. Sadly, they didn’t actually build a sci-fi space glider; this study is limited to the physics involved. But the study claims “space soaring” could get a spacecraft to half a percent the speed of light within a month, and two percent in perhaps a year and a half. That’s enough to get us to Alpha Centauri within a few hundred years.

Mars Updates: Ingenuity Soars While Magma Plume Rises

A team of researchers working with data from NASA’s InSight Mars lander has reported what may be tectonic activity on Mars. Models suggest a mantle plume rising beneath Elysium Planitia, a flat region in the planet’s northern lowlands. InSight’s analysis of marsquakes shows that almost all of them originate from a series of fissures in Elysium Planitia, known as Cerberus Fossae. Craters there are tilted toward the plume in a way that shows the plume continued to swell upwards long after the craters were formed.

Beneath the fissures of Cerberus Fossae (center), an enormous mantle plume rises. Click here to read more.

Speaking of craters on the Red Planet, a study of a different Martian crater reports evidence of an ancient megatsunami on Mars. The crater’s size and erosion suggest that a 3km impactor created it some 3.4 billion years ago. At the time, the report says, that location was in the middle of a shallow sea. The impact would have scoured the ocean floor down into the bedrock, and created a wall of water more than eight hundred feet high. This would explain how all that ejecta and rubble got to the Viking 1 probe’s landing site, when there weren’t any craters nearby.

Elsewhere on Mars, NASA’s space helicopter Ingenuity reached a record height on its 35th flight, the agency announced in a Monday tweet. Ingenuity has covered more than four and a half miles in its time on Mars. In total, it has logged almost an hour of total flight time.

Ingenuity won our hearts, but it didn’t stop there. The little copter that could is changing how NASA approaches space exploration. The helicopter’s dazzling success influenced NASA’s recent decision to scrap a rover for two helicopters on the upcoming Mars Sample Return mission.

NASA Loses Contact With ICON Satellite

In a brief Wednesday statement, NASA confirmed it has lost contact with its Ionospheric Connection Explorer (ICON) satellite. ICON is well beyond its design lifetime, and the agency lost connection with the satellite on Nov. 25. It hasn’t responded to hails ever since.

“The team is currently still working to establish a connection,” said agency spokesperson Denise Hill. “Working with the Department of Defense’s Space Surveillance Network, the team has verified that ICON remains intact.”

Unfortunately, that’s about all the good news for the mission. ICON has a built-in timer that resets the spacecraft if it goes eight days without communicating with ground control. Even after the reset was completed on Monday (Dec. 5), the satellite is still radio silent. But it’s a full year beyond ICON’s original design lifetime of two years. Even if it’s curtains for ICON, the satellite had a good run.

Nuclear Waste Could Make Batteries That ENDURE Deep Space Travel

Scientists with the European Space Agency (ESA) are studying a way to turn nuclear waste into something genuinely useful — a new kind of battery that could power the agency’s moon missions by the early 2030s. The project is called European Devices Using Radioisotope Energy (ENDURE).

Historically, the ESA has relied on plutonium-238 batteries from the US or Russia for missions that can’t make do with solar power. But plutonium-238 is scarce and expensive. After Putin’s forces invaded Ukraine, the ESA cut ties with Russia, and the supply of Russian plutonium dried up entirely. So the agency is turning to americium, a by-product of nuclear waste from power plants. It’s less energy-dense than plutonium, but it’s also much more readily available.

Wednesday’s full moon, also known as the Cold Moon, as seen from the International Space Station. Image: NASA, via Johnson Space Center Flickr

ENDURE researchers from the UK’s University of Leicester have already designed two different americium power packs. One is a heating unit that uses heat from the decaying isotope directly. The other produces power by way of a radioisotope thermoelectric generator (RTG), not unlike the ones NASA uses.

While the ESA hopes to use these americium power packs for their Argonaut lunar landers in the 2030s, project spokesperson Markus Landgraf said that NASA also considers the americium tech “very interesting” with respect to future Artemis missions. ESA is also eyeing a mission to Uranus and Neptune in the 2040s.

JWST Images Reveal ‘Unseen Companions’ Within Southern Ring Nebula

An analysis of early images from the James Webb Space Telescope indicates that the Southern Ring Nebula may have been shaken — and stirred.

This six-panel image shows different views of the Southern Ring Nebula. The numbers 1-5 correspond to five different stars, with 1 being the dying star that created the nebula. Image credits: NASA, ESA, CSA, E. Wheatley (STScI)

The Southern Ring Nebula was one of the earliest science images from the JWST. But a closer look showed that there were two other unseen stars orbiting the trio of stars at the center of the nebula. Data from the European Space Agency’s Gaia spacecraft helped to precisely determine the central star’s mass: about triple the mass of the Sun.

When that central star exploded, its companion stars went off like a chain reaction, shocking the supernova’s ejecta and releasing their own relativistic jets. (Those jets are the bright streaks that cross the second and third panels.) But they kept on orbiting, hidden within a shroud of gas and dust. Two other “unseen companions” then began to show their own influence. One skewed the jets into a spiral, like spin art, and the other stirred the cloud of ejections “like a spatula running through batter.” The quintet’s hidden dance is responsible for the nebula’s wobbly shape.

Scientists Analyzing China’s Space-Grown Rice

Crew aboard the International Space Station have to become a kind of polymath, as they’ll be doing everything from botany to physics to medical research and emptying space toilets. And it’s clearly much the same aboard China’s Tiangong space station. This week, the Chinese Space Agency said, scientists earthside are taking over from the Shenzhou-14 astronauts, who have been analyzing a truly far-out plant: rice grown in orbit.

Photo: Xinhua

According to the Chinese State Council, this is the first time anyone has successfully grown rice in space. The astronauts spent months tending the heavenly sprouts alongside Thale cress, a common ‘testbed’ plant with a simple genome, also known as Arabidopsis. Meanwhile, scientists at the Chinese Academy of Sciences (CAS) grew the same seeds in Earth’s gravity, as controls. The space agency will now transfer the orbital rice samples to Shanghai, for further analysis.

Skywatchers Corner

This week’s standout is the Geminid meteor shower, which runs until Dec. 20 this year, peaking on Dec. 13-14. Unfortunately, the waning half-moon, or next week’s expected inclement weather, may interfere. At its peak, the shower may offer perhaps thirty or forty meteors an hour. The crest comes around 2 a.m. on Dec. 14, but the show starts around 9-10 p.m., which is more accessible to kids. For best viewing conditions, don’t look straight at the constellation of Gemini; instead, lie on your back, with your feet facing south.

The Geminids are debris from an active, 3.6-mile-wide Apollo asteroid named 3200 Phaethon, en homage to Phaëthon, son of the Greek sun god Helios. It’s a rocky asteroid, but it has a tail like a comet — hence the “active.” Every year, this shower gets more intense. And the name fits; Phaethon’s orbit brings it closer to the Sun than any other named asteroid. Phaethon is also the first asteroid discovered using a spacecraft: the IRAS satellite, a space telescope that surveyed the entire night sky in the infrared.

2017 sky path of Phaethon, by Tomruen (CC BY-SA 4.0)

Because of its close passes and its size, Phaethon is classified as a potentially hazardous asteroid. However, its orbit is well understood, and there’s little uncertainty in the path the asteroid will take. During the 2017 Geminid shower, Phaethon passed within 6.4 million miles of Earth — not quite thirty times the distance from the Earth to the Moon. At that distance, we could pinpoint where it was, with an error of less than a kilometer in any direction. Arecibo and other observatories took advantage of the asteroid’s proximity, making observations of unprecedented resolution. But that approach pales in comparison to the asteroid’s 2093 flyby of Earth. On Dec. 14 of that year, Phaethon will pass within two million miles of our pale blue dot.

The end of the Geminids will overlap with another meteor shower, the Ursids, which run from Dec. 17-26. As you might expect from their name, the Ursids appear to radiate from Ursa Minor, the Little Dipper. This meteor shower has a narrow ‘stream’ of debris; the best viewing opportunities come within 12-24 hours of the shower’s peak, and even during that time, there are just five to 10 meteors per hour. Happily, this year’s peak coincides with the new moon on Dec. 22-23.

That’s all for this week. But you can join us to watch NASA’s live coverage of the Orion splashdown, beginning at 11 a.m. EST on Sunday.

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