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When Longfellow wrote about “ships passing in the night” back in 1863, he probably wasn’t thinking about satellites passing near Venus.  He probably also wouldn’t have considered 575,000 km separation as “passing”, but on the scale of interplanetary exploration, it might as well be.  And passing is exactly what two satellites will be doing near Venus in the next few days – performing two flybys of the planet within 33 hours of each other.

The two spacecraft in question are Solar Orbiter and BepiColombo.  Neither is focused on the Venus system itself, but is simply using the planet for a gravity assist to get to their final destinations – the sun’s poles and Mercury respectively.  It just so happens that they will be passing by our sister planet at around the same time.

Depiction of BepiColombo’s Venus flyby.
Credit – ESA / ATG Media Lab / SciTechDaily YouTube Channel

This isn’t Solar Orbiter’s first merry-go-round with the planet, having used Venus as a gravity assist previously, and with potentially 6 more to go.  All of those assists are to help the probe go where no machine has gone before – high enough above and below the sun to get clear images of its poles, where it hopes to get more information about the solar cycle.  

BepiColombo, on the other hand, is on its second and final Venus flyby, though it still has plenty more assists from Mercury itself before it finally settles into a stable orbit in 2025.  It will pass by Venus much more closely than its traveling companion, with an altitude of 550 km compared to 7995 km for Solar Orbiter.  

Depiction of Solar Orbiter’s second (of potentially six) Venus flybys.
Credit – ESA / ATG Media Lab / SciTechDaily YouTube Channel

Unfortunately, the distance between them is too great to expect a picture of one craft from the other.  In fact, Solar Orbiter won’t be taking any visible light images of Venus this time around at all, as the probe must remain facing the Sun itself.  BepiColombo won’t be able to turn its main camera toward the planet either, but two of its three “monitoring cameras” will be snapping as it goes past. In fact the spacecraft might also capture its own antenna and solar arrays in the picture.  Though the pictures are only 1024×1024 resolution, they will be sent back to Earth gradually following the BepiColombo’s flyby on August 10th.  

BepiColombo images Venus during close approach article 1
Image taken from the first BepiColombo Venus flyby. The same cameras will be available for use this time around.
Credit – ESA / BepiColombo / MTM

Other non-visual instruments on both spacecraft will be going full bore however.  This would include Solar Orbiter’s SoloHI imager, usually used to image the solar wind, magnetic field sensors, and plasma sensors.  In addition, there’s already a Venus orbiter in place around the planet – JAXA’s Akatsuki – which can collect additional data at the same time, allowing scientists to try to collate data points from many different physical locations as well as sensing modalities.  

UT video discussing the Solar Orbiter mission.

Close flybys like these are a great sideshow to the true science these orbiters will pursue once reaching their final destinations.  It also provides a good warm up for them, and their handlers, to get the jitters out of their system.  The fact that they happen to be passing by each other in such close succession on their journeys to their final destinations just makes it all the more interesting of a story.

Learn More:
ESA – ESA gets ready for double Venus flyby
spacewatch.global – Solar Orbiter and BepiColombo to make history with double Venus flyby
New Atlas – Venus will receive two visitors from Earth next week
S&T – TWO SPACE PROBES TO PASS BY VENUS NEXT WEEK

Lead Image:
Depiction of BepiColombo & Solar Orbiter passing by Venus in close succession.
Credit – ESA

The post Two Spacecraft are Flying Past Venus, Just 33 Hours Apart appeared first on Universe Today.

Did you miss our previous article…
https://www.mansbrand.com/shadows-on-the-moon-could-be-hiding-water-even-in-the-daytime/

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Should We Send Humans to Venus?

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NASA is preparing to send humans back to the Moon with the Artemis missions in the next few years as part of the agency’s Moon to Mars Architecture with the long-term goal of landing humans on the Red Planet sometime in the 2030s or 2040s. But what about sending humans to other worlds of the Solar System? And, why not Venus? It’s closer to Earth than Mars by several tens of millions of kilometers, and despite its extremely harsh surface conditions, previous studies have suggested that life could exist in its clouds. In contrast, we have yet to find any signs of life anywhere on the Red Planet or in its thin atmosphere. So, should we send humans to Venus?

“Yes, we should send humans to Venus,” Dr. Paul Byrne, who is an Associate Professor of Earth, Environmental, and Planetary Sciences at Washington University in St. Louis, tells Universe Today. “But first, let’s talk about what ‘sending humans to Venus’ actually means. The surface of Venus is hellish, so nobody would last long there nor volunteer to go. Above the clouds, the temperature and pressure are almost like a nice spring day here on Earth, so aside from tiny sulphuric acid cloud droplets you’d be okay (with a breathing apparatus).”

These “hellish” conditions that Dr. Byrne alludes to are the extreme conditions across the surface of Venus, including surface pressures 92 times that of Earth’s surface and average surface temperatures of approximately 464 degrees Celsius (867 degrees Fahrenheit). In contrast, Earth’s average surface temperatures are a calm 15 degrees Celsius (59 degrees Fahrenheit). These extreme pressures and temperatures have made landing on the surface of Venus even more difficult, as the former Soviet Union continues to be the only nation to have successfully landed on Venus’ surface, having accomplished this feat with several of their Venera and Vega missions. However, the longest mission duration for the lander was only 127 minutes (Venera 13), which also conducted the first sound recording on another planet.

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Color images taken by the Soviet Union’s Venera 13 lander on the surface of Venus on March 1, 1982, with the lander surviving only 127 minutes due to Venus’s extreme surface conditions. (Credit: NASA)

“If we were to send humans to Venus, they’d be going in a spacecraft that would fly by the planet en route somewhere else,” Dr. Byrne tells Universe Today. “If we were to one day send humans actually to Venus itself for science and engineering purposes, then a cloud-based habitat is the way to go. Getting humans onto the Venus surface is going to require so much technology and expense that, for the foreseeable future, I don’t think anyone will think it worth doing.”

A 2015 study presented at the AIAA Space and Astronautics Forum and Exposition outlined a NASA study for the High Altitude Venus Operational Concept (HAVOC) mission that would involve a 30-day crewed mission using an airship equipped with solar panels within the upper atmosphere of Venus. This is because Venus’ upper atmosphere at approximately 50 kilometers (30 miles) above the surface exhibits much more hospitable conditions, including temperatures between 30 to 70 degrees Celsius (86 to 158 degrees Fahrenheit) and pressures very close to that of Earth. However, Dr. Byrne refers to HAVOC as an “unbelievably expensive concept”.

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Artist rendition of proposed habitable airships traversing Venus’ atmosphere, which has been proposed as the High Altitude Venus Operational Concept (HAVOC) mission. (Credit: NASA)

As for using Venus while en route to another location in the Solar System, Venus has been used on several occasions to slingshot spacecraft to the outer Solar System as well as for exploration of the inner Solar System, such as Mercury and the Sun. For example, NASA’s Galileo and Cassini spacecraft used gravity assists

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Frontier Adventure

We Should Hit Peak Solar Activity Next Year

NASAs SDO Observes Largest Sunspot of the Solar Cycle 15430820129 jpeg

You may be familiar with the solar cycle that follows a 22 year process shifting from solar minimum to maximum and back again. It’s a cycle that has been observed for centuries yet predicting its peak has been somewhat challenging. The Sun’s current cycle is approaching maximum activity which brings with it higher numbers of sunspots on its surface, more flares and more coronal mass ejections. A team from India now believe they have discovered a new element of the Sun’s magnetic field allowing them to predict the peak will occur early in 2024.

The Sun is a gigantic sphere of plasma or electrically charged gas. One of the features of plasma is that if a magnetic field passes through it, the plasma moves with it. Conversely if the plasma moves, the magnetic field moves too. This magnetic field is just like Earth and is known as a dipole magnetic field. You can visualise it if you can remember your school science days with a bar magnet and iron filings.

A dipole magnetic field has two opposite but equal charges and at the start of the Sun’s cycle the field lines effectively run from the north pole to the south. As the Sun rotates, with the equator rotating faster than the polar regions, then the plasma drags the magnetic field lines with it, winding them tighter and tighter.

The field lines become stretched causing the magnetic field to loop up and through the visible surface of the Sun. This localised event prevents the convection of super heated gas from underneath and appears as a cooler area of the surface which appears dark. As the solar cycle starts, these sunspots appear around the polar regions and slowly migrate toward the equator as it progresses with peak activity occurring when the sunspots fade away as we head toward the start of another cycle. 

NASAs SDO Observes Largest Sunspot of the Solar Cycle 15430820129 1 jpeg
Image of sunspots (Credit : NASA Goddard Space Flight Center // SDO)

On occasions the magnetic field of sunspots are disrupted and we can experience flares or coronal mass ejections hurling vast amounts of charged particles out into space. If they reach us here on Earth they give rise to the beautiful aurora displays but they do also have a rather negative impact to satellites, power grids and telecommunications systems.

Deep inside the Sun, a dynamo mechanism is driving all this. It is created by the energy from the movement of plasma and it is this that is responsible for the flipping of the Sun’s magnetic poles where the north pole becomes south and the south pole becomes north which happens every 11 years or so. It’s another aspect of the solar cycle.

It’s been known since the 1930’s that the rate of rise the sunspot cycle relates to its strength with stronger cycles taking less time to reach peak. In the paper published in the Monthly Notices of the Royal Astronomical Society Letters; Priyansh Jaswal, Chitradeep Saha and Dibyendu Nandy from the Indian Institutes of Science Education and Research announced their findings. They discovered that the rate of decrease in the Sun’s dipole magnetic field also seems to relate to the rise of the present cycle.

The team have looked back through archives and have shown how the observation of the dipole decrease rate along with observations of sunspots can predict the peak of activity with better accuracy than before. They conclude the current cycle is expected to peak somewhere between early 2024 and September next year. Being able to better predict the peak of activity will help understand the likely intensity of space weather events here on Earth providing us more warning to be able to prepare.

Source : Solar activity likely to peak next year, new study suggests

The post We Should Hit Peak Solar Activity Next Year appeared first on Universe Today.

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The Solar Radius Might Be Slightly Smaller Than We Thought

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Two astronomers use a pioneering method to suggest that the size of our Sun and the solar radius may be due revision.

Our host star is full of surprises. Studying our Sun is the most essential facet of modern astronomy: not only does Sol provide us with the only example of a star we can study up close, but the energy it provides fuels life on Earth, and the space weather it produces impacts our modern technological civilization.

Now, a new study, titled The Acoustic Size of the Sun suggests that a key parameter in modern astronomy and heliophysics—the diameter of the Sun—may need a slight tweak.

The study out of the University of Tokyo and the Institute of Astronomy at Cambridge was done looking at data from the joint NASA/ESA Solar Heliospheric Observatory (SOHO’s) Michelson Doppler Imager (MDI) imager. The method probes the solar interior via acoustics and a cutting edge field of solar physics known as helioseismology.

Interior of the Sun
A cutaway diagram of the Sun. NASA/ESA/SOHO

‘Hearing’ the Solar Interior

How can you ‘hear’ acoustic waves on the Sun? In 1962, astronomers discovered that patches on the surface of the Sun oscillate, or bubble up and down, like water boiling on a stove top. These create waves that ripple in periodic 5-minute oscillations across the roiling surface of the Sun.

SOHO SDO
A view of the Sun, courtesy of SOHO’s MDI instrument. Credit: NASA

What’s more, astronomers can use what we see happening on the surface of the Sun to model the solar interior, much like terrestrial astronomers use seismic waves traveling through the Earth to model its core. Thanks to helioseismology, we can even ‘see’ what’s going on on the solar farside, and alert observers of massive sunspots before they rotate into view.

Solar Ffarside
Solar farside modeling using helioseismology. Credit: NSF/GONG

The study looked at p-mode waves as they traversed the solar interior. Previous studies relied on less accurate f-mode waves, which are surface waves considerably shorter than the solar radius.

The study defines the solar radius (half the diameter) as 695,780 kilometers… only slightly smaller than the generally accepted radius of 696,000 kilometers obtained by direct optical measurement. This is only smaller by a few hundredths of a percent, or 100-200 kilometers.

SOHO
An artist’s conception of SOHO in space. Credit: ESA/SOHO

The solar radius is a deceptively simple but crucial factor in astronomy. The Sun is a glowing ball of hydrogen and helium plasma without a distinct surface boundary. The photosphere—the glowing visible layer we see shining down on us on a sunny day—is what we generally refer to as the surface of the Sun.

The Solar Radius: A Brief
Did you miss our previous article…
https://mansbrand.com/if-warp-drives-are-impossible-maybe-faster-than-light-communication-is-still-on-the-table/

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