24/7 Space News
SOLAR SCIENCE
Seventeen years later satellite return home for first time
NASA's STEREO-A spacecraft will cross the Sun-Earth line on Aug. 12, 2023. The crossing comes one day before Venus passes between the Sun and Earth, though the planet will appear 10 degrees below the Sun from Earth's view and outside of STEREO-A's field of view. See gif here
Seventeen years later satellite return home for first time
by Miles Hatfield for GSFC News
Greenbelt MD (SPX) Aug 11, 2023

On Aug. 12, 2023, NASA's STEREO-A spacecraft will pass between the Sun and Earth, marking the first Earth flyby of the nearly 17-year-old mission. The visit home brings a special chance for the spacecraft to collaborate with NASA missions near Earth and reveal new insights into our closest star.

The twin STEREO (Solar TErrestrial RElations Observatory) spacecraft launched on Oct. 25, 2006, from the Cape Canaveral Air Force Station in Florida. STEREO-A (for "Ahead") advanced its lead on Earth as STEREO-B (for "Behind") lagged behind, both charting Earth-like orbits around the Sun.

During the first years after launch, the dual-spacecraft mission achieved its landmark goal: providing the first stereoscopic, or multiple-perspective, view of our closest star. On Feb. 6, 2011, the mission achieved another landmark: STEREO-A and -B reached a 180-degree separation in their orbits. For the first time, humanity saw our Sun as a complete sphere.

"Prior to that we were 'tethered' to the Sun-Earth line - we only saw one side of the Sun at a time," said Lika Guhathakurta, STEREO program scientist at NASA Headquarters in Washington, D.C. "STEREO broke that tether and gave us a view of the Sun as a three-dimensional object."

The mission accomplished many other scientific feats over the years, and researchers studied both spacecraft views until 2014, when mission control lost contact with STEREO-B after a planned reset. However, STEREO-A continues its journey, capturing solar views unavailable from Earth.

On Aug. 12, 2023, STEREO-A's lead on Earth has grown to one full revolution as the spacecraft "laps" us in our orbit around the Sun. In the few weeks before and after STEREO-A's flyby, scientists are seizing the opportunity to ask questions normally beyond the mission's reach.

A 3D View of the Sun
During the Earth flyby, STEREO-A will once again do something it used to do with its twin in the early years: combine views to achieve stereoscopic vision.

Stereoscopic vision allows us to extract 3D information from two-dimensional, or flat, images. It's how two eyeballs, looking out at the world from offset locations, create depth perception. Your brain compares the images from each eye, and the slight differences between those images reveal which objects are closer or farther away.

STEREO-A will enable such 3D viewing by synthesizing its views with NASA's and the European Space Agency's Solar and Heliospheric Observatory (SOHO) and NASA's Solar Dynamics Observatory (SDO). Better yet, STEREO-A's distance from Earth changes throughout the flyby, optimizing its stereo vision for different sized solar features at different times. It's as if scientists were adjusting the focus on a several million-mile-wide telescope.

STEREO scientists are using the opportunity to make much-needed measurements. They are identifying active regions, the magnetically complex regions underlying sunspots, hoping to uncover 3D information about their structure usually lost in 2D images. They'll also test a new theory that coronal loops - giant arches often seen in close-up images of the Sun - aren't what they appear to be.

"There is a recent idea that coronal loops might just be optical illusions," said Terry Kucera, STEREO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Some scientists have suggested that our limited viewing angles make them appear to have shapes they may not truly have. "If you look at them from multiple points of view, that should become more apparent," Kucera added.

Inside a Solar Eruption
It's not just what STEREO-A will see as it flies by Earth, but also what it will "feel," that could lead to major discoveries.

When a plume of solar material known as a coronal mass ejection, or CME, arrives at Earth, it can disrupt satellite and radio signals, or even cause surges in our power grids. Or, it may have hardly any effect at all. It all depends on the magnetic field embedded within it, which can change dramatically in the 93 million miles between the Sun and Earth.

To understand how a CME's magnetic field evolves on the way to Earth, scientists build computer models of these solar eruptions, updating them with each new spacecraft observation. But a single spacecraft's data can only tell us so much.

"It's like the parable about the blind men and the elephant - the one who feels the legs says 'it's like a tree trunk,' and the one who feels the tail says 'it's like a snake,'" said said Toni Galvin, a professor at the University of New Hampshire and principal investigator for one of STEREO-A's instruments. "That's what we're stuck with right now with CMEs, because we typically only have one or two spacecraft right next to each other measuring it."

During the months before and after STEREO-A's Earth flyby, any Earth-directed CMEs will pass over STEREO-A and other near-Earth spacecraft, giving scientists much-needed multipoint measurements from inside a CME.

A Fundamentally Different Sun
STEREO-A was also close to Earth in 2006, shortly after launch. That was during "solar minimum," the low-point in the Sun's roughly 11-year cycle of high and low activity.

"The Sun was so quiet at that point! I was looking back at the data and I said 'Oh yeah, I recognize that active region' - there was one, and we studied it," Kucera said, laughing. "OK, it wasn't quite that bad - but it was close."

Now, as we approach solar maximum predicted for 2025, the Sun isn't quite so sleepy.

"In this phase of the solar cycle, STEREO-A is going to experience a fundamentally different Sun," Guhathakurta said. "There is so much knowledge to be gained from that."

Related Links
STEREO at NASA
Solar Science News at SpaceDaily

Subscribe Free To Our Daily Newsletters
Tweet

RELATED CONTENT
The following news reports may link to other Space Media Network websites.
SOLAR SCIENCE
Giant solar eruption felt on Earth, Moon and Mars
Paris (ESA) Aug 04, 2023
A solar eruption detected simultaneously at Earth, the Moon and Mars emphasises the need to prepare human exploration missions for the dangers of space radiation. A coronal mass ejection erupted from the Sun on 28 October 2021 and was spread over such a wide area that Mars and Earth, while on opposite sides of the Sun and around 250 million kilometres apart, received an influx of energetic particles. This marks the first time that a solar event was measured simultaneously on the surfaces of Earth, ... read more

SOLAR SCIENCE
Indian lunar lander splits from propulsion module in key step

NASA challenges students to fly Earth and Space experiments

Virgin Galactic rockets its first tourist passengers into space

Embracing the future we need

SOLAR SCIENCE
China's Kuaizhou-1A rocket launches five new satellites

Pulsar Fusion forms partnership with University of Michigan for electric propulsion

China's commercial CERES-1 Y7 rocket launches 7 satellites

Musk says cage fight with Zuckerberg will be in Italy

SOLAR SCIENCE
Delight at Dream Lake

Cracks in ancient Martian mud surprise Curiosity team

A 'Blissful' Martian Rock Paradise, Straight Ahead: Sols 3919-3920

Engineers put a Mars lander legs to the test

SOLAR SCIENCE
China to launch "Innovation X Scientific Flight" program, applications open worldwide

Scientists reveal blueprint of China's lunar water-ice probe mission

Shenzhou 15 crew share memorable moments from Tiangong Station mission

China's Space Station Opens Doors to Global Scientific Community

SOLAR SCIENCE
Intelsat completes C-Band spectrum clearing for 5G Deployment

SpaceX successfully launches another batch of Starlink satellites

Atlas Credit Partners provides $100M strategic financing to AST SpaceMobile

ESA's Space Environment Report 2023

SOLAR SCIENCE
ESA integrates Satellite Orbit Decay Forecast service to enhance satellite safety

SwRI micropatch algorithm improves ground-to-spacecraft software update efficiency

Before the vacuum

De-orbiting PS4 stage in PSLV-C56 Mission

SOLAR SCIENCE
Watch an exoplanet's 17-year journey around its star

Exoplanet surveyor Ariel passes major milestone

The oldest and fastest evolving moss in the world might not survive climate change

Chemical contamination on International Space Station is out of this world

SOLAR SCIENCE
NASA's Europa probe gets a hotline to Earth

All Eyes on the Ice Giants

Hundred-year storms? That's how long they last on Saturn.

Looking for Light with New Horizons

Subscribe Free To Our Daily Newsletters


ADVERTISEMENT



The content herein, unless otherwise known to be public domain, are Copyright 1995-2023 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.