NASA’s Parker Solar Probe has racked up an impressive list of superlatives in its first five years of operations: It’s the closest spacecraft to the sun, the fastest human-made object and the first mission to ever “touch the sun.”

 

Now, Parker has one more feather to add to its sun-kissed cap: It’s the first spacecraft ever to fly through a powerful solar explosion near the sun.

As detailed in a new study published Sept. 5 in The Astrophysical Journal—exactly one year after the event occurred—Parker Solar Probe passed through a coronal mass ejection (CME).

These fierce eruptions can expel magnetic fields and sometimes billions of tons of plasma at speeds ranging from 60 to 1,900 miles (100 to 3,000 kilometers) per second. When directed toward Earth, these ejections can bend and mold our planet’s magnetic field, generating spectacular auroral shows and, if strong enough, potentially devastate satellite electronics and electrical grids on the ground.

Cruising on the far side of the sun just 5.7 million miles (9.2 million kilometers) from the solar surface—22.9 million miles (36.8 million kilometers) closer than Mercury ever gets to the sun—Parker Solar Probe first detected the CME remotely before skirting along its flank. The spacecraft later passed into the structure, crossing the wake of its leading edge (or shock wave), and then finally exited through the other side.

In all, the sun-grazing spacecraft spent nearly two days observing the CME, providing physicists an unparalleled view into these stellar events and an opportunity to study them early in their evolution.

“This is the closest to the sun we’ve ever observed a CME,” said Nour Raouafi, the Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, which built the spacecraft within NASA’s timeline and budget, and currently manages and operates the mission. “We’ve never seen an event of this magnitude at this distance.”

The CME on Sept. 5, 2022, was an extreme one. As Parker passed behind the shock wave, its Solar Wind Electrons, Alphas and Protons (SWEAP) instrument suite clocked particles accelerating up to 840 miles (1,350 kilometers) per second. Had it been directed toward Earth, Raouafi suspects it would have been close in magnitude to the Carrington Event—a solar storm in 1859 that is held as the most powerful on record to hit Earth.

[…]

More information: O. M. Romeo et al, Near-Sun In Situ and Remote-sensing Observations of a Coronal Mass Ejection and its Effect on the Heliospheric Current Sheet, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/ace62e

Source: Parker Probe’s path through solar blast yields unparalleled space weather insights

A recent study submitted to Acta Astronautica explores the potential for using aerographite solar sails for traveling to Mars and interstellar space, which could dramatically reduce both the time and fuel required for such missions. This study comes while ongoing research into the use of solar sails is being conducted by a plethora of organizations along with the successful LightSail2 mission by The Planetary Society, and holds the potential to develop faster and more efficient propulsion systems for long-term space missions.

“Solar sail propulsion has the potential for rapid delivery of small payloads (sub-kilogram) throughout the solar system,” Dr. René Heller, who is an astrophysicist at the Max Planck Institute for Solar System Research and a co-author on the study, tells Universe Today. “Compared to conventional chemical propulsion, which can bring hundreds of tons of payload to low-Earth orbit and deliver a large fraction of that to the Moon, Mars, and beyond, this sounds ridiculously small. But the key value of solar sail technology is speed.”

Unlike conventional rockets, which rely on fuel in the form of a combustion of chemicals to exert an external force out the back of the spacecraft, solar sails don’t require fuel. Instead, they use sunlight for their propulsion mechanism, as the giant sails catch solar photons much like wind sails catching the wind when traveling across water. The longer the solar sails are deployed, the more solar photons are captured, which gradually increases the speed of the spacecraft.

For the study, the researchers conducted simulations on how fast a solar sail made of aerographite with a mass up to 1 kilogram (2.2 pounds), including 720 grams of aerographite with a cross-sectional area of 10⁴ square meters, could reach Mars and the interstellar medium, also called the heliopause, using two trajectories from Earth known as direct outward transfer and inward transfer methods, respectively.

The direct outward transfer method for both the trip to Mars and the heliopause involved the solar sail both deploying and departing directly from a polar orbit around the Earth. The researchers determined that Mars being in opposition (directly opposite Earth from the Sun) at the time of solar sail deployment and departure from Earth would yield the best results for both velocity and travel time. This same polar orbit deployment and departure was also used for the heliopause trajectory, as well. For the inward transfer method, the solar sail would be delivered to approximately 0.6 astronomical units (AU) from the Sun via traditional chemical rockets, where the solar sail would deploy and begin its journey to either Mars or the heliopause. But how does an aerographite solar sail make this journey more feasible?

“With its low density of 0.18 kilograms per cubic meter, aerographite undercuts all conventional solar sail materials,” Julius Karlapp, who is a Research Assistant at the Dresden University of Technology and lead author of the study, tells Universe Today. “Compared to Mylar (a metallized polyester foil), for example, the density is four orders of magnitude smaller. Assuming that the thrust developed by a solar sail is directly dependent on the mass of the sail, the resulting thrust force is much higher. In addition to the acceleration advantage, the mechanical properties of aerographite are amazing.”

Through these simulations, the researchers found the direct outward transfer method and inward transfer method resulted in the solar sail reaching Mars in 26 days and 126 days, respectively, with the first 103 days being the travel time from Earth to the deployment point at 0.6 AU. For the journey to the heliopause, both methods resulted in 5.3 years and 4.2 years, respectively, with the first 103 days of the inward transfer method also being devoted to the travel time from the Earth to the deployment point at 0.6 AU, as well. The reason the heliopause is reached in a faster time with the inward transfer method is due to the solar sail achieving maximum speed at 300 days, as opposed to achieving maximum speed with the outward transfer method at approximately 2 years.

Current travel times to Mars range between 7-9 months, which only happens during specified launch windows every two years while relying on the positions of both planets to be aligned at both launch and arrival of any spacecraft going to, or coming from, Mars. Estimating current travel times to the heliopause can be done using NASA’s Voyager 1 and Voyager 2 probes, which reached the heliopause at approximately 35 years and 41 years, respectively.

The researchers note that one major question of using solar sails is deceleration, or slowing down, upon arriving at the destination, specifically Mars, and while they mention aerocapture as one solution, they admit this still requires further study.

“Aerocapture maneuvers for hyperbolic trajectories (like flying from Earth to Mars) use the atmosphere to gradually reduce velocity due to drag,” Dr. Martin Tajmar, who is a physicist and Professor of Space System at the Dresden University of Technology and a co-author on the study, tells Universe Today. “Therefore, less fuel is required to enter the Martian orbit. We use this braking maneuver to eliminate the need for additional braking thrusters, which in turn reduces the mass of the spacecraft. We’re currently researching what alternative strategies might work for us. Yet the braking method is only one of many different challenges we are currently facing.”

While solar sail technology has been proposed by NASA as far back as the 1970s, a recent example of solar sail technology is the NASA Solar Cruiser, which is currently scheduled to launch in February 2025.

What new discoveries will researchers make about solar sail technology in the coming years and decades? Only time will tell, and this is why we science!

Source: Solar Sails Could Reach Mars in Just 26 Days – Universe Today

OSIRIS-REx weighs 4,650 pounds (or 2,110 kg). On September 8th of 2016, NASA first launched the spacecraft on its 3.8-billion mile mission to land on an asteroid and retrieve a sample.

That sample has just returned.

Throughout Sunday morning, NASA tweeted historic updates from the sample’s landing site in Utah. “We’ve spotted the #OSIRISREx capsule on the ground,” they announced about 80 minutes ago (including a 23-second video clip). “The parachute has separated, and the helicopters are arriving at the site. We’re ready to recover that sample!”

UPI notes that the capsule “reached temperatures up to 5,000 degrees Fahrenheit during reentry, so protective masks and gloves are required to handle it,” describing its payload as “a 250-gram dust sample.”

15 minutes later NASA shared footage of “the first persons to come into contact with this hardware since it was on the other side of the solar system.” A recovery team approached the capsule to perform an environmental safety sweep confirming there were no hazardous gas.

“The impossible became possible,” NASA administrator Bill Nelson said in a statement. The Guardian reports he confirmed the capsule “brought something extraordinary — the largest asteroid sample ever received on Earth.

“It’s going to help scientists investigate planet formation, it’s going to improve our understanding of the asteroids that could possibly impact the earth and it will deepen our understanding of the origin of our solar system and its formation.”

“This mission proves that NASA does big things, things that have inspired us, things that unite us…

“The mission continues with incredible science and analysis to come. But I want to thank you all, for everybody that made this Osiris-Rex mission possible.”

Professor Neil Bowles of the University of Oxford, one of the scientists who will study the sample, told the Guardian that he was excited to see the sample heading to the clean room at Johnson Space Center. “So much new science to come!”

And that 4,650-pound spacecraft is still hurtling through space. 20 minutes after delivering its sample, the craft ” fired its engines to divert past Earth toward its new mission to asteroid Apophis,” NASA reports. The name of its new mission? OSIRIS-APEX. Roughly 1,000 feet wide, Apophis will come within 20,000 miles of Earth — less than one-tenth the distance between Earth and the Moon — in 2029. OSIRIS-APEX is scheduled to enter orbit of Apophis soon after the asteroid’s close approach of Earth to see how the encounter affected the asteroid’s orbit, spin rate, and surface.

Source: After Seven Years, Sample Collected From Asteroid Finally Returns to Earth – Slashdot