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What It Would Take to Bring the ISS Back to Earth in One Piece – Verve Times

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To keep the ISS orbiting until 2031, the space agencies that maintain it need to periodically do something to counteract this drag force. The ISS doesn’t have its own rocket engines, so it needs a reboost, or a push from a resupply craft. A reboost nudges the space station and increases its velocity. (Here is a bonus: My analysis of what it’s like to be an astronaut inside the ISS during a reboost, posted on the European Space Agency’s blog.)

Would the ISS Burn Up on Reentry?

Although reentry can be a violent event and completely destroy many objects, it’s quite possible that something the size of the ISS would at least partially survive. As an example, pieces of Skylab made it through the atmosphere upon reentry in 1979 and hit the Earth as debris.

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But anything that falls through the atmosphere gets super hot. Orbital objects are going really fast, and when they start to move through the atmosphere, they push the air in front of them, because that air gets in their way. Some of this air gets pushed to the side, but much of it is pushed forward. This is a problem—because there is already air there. Pressing more air into the same space causes a compression. You might have noticed while pumping up a bike tire that the tire gets hot as you pump more air in; it’s because it’s compressing the air already in the tube. The same thing happens as an object moves quickly through the atmosphere: The compressed air in front of it heats up, and the object itself gets hot. Like, “melt stuff” levels of hot.

Some spacecraft, like the Space Shuttle or the SpaceX Crew Dragon, have a heat shield, material that insulates the rest of the craft from all that hot air. But the ISS doesn’t have a heat shield. So at the very least, parts of it would burn up on reentry.

The remaining debris might make it to a museum exhibit, but not one you could walk through.

Could We Get the ISS Down Without a Normal Reentry?

There’s a difference between reentry and simply falling from space. If you just take an object up to an altitude of 400 kilometers and drop it, that’s significantly different than reentry. Remember, objects in LEO are moving super fast, while a “dropped” object would start with a velocity of zero meters per second. Yes, the dropped object would speed up and get hot—but not nearly as hot as an object reentering from orbit.

So consider this: What if we used some rockets to stop the ISS in its orbit, and then brought it straight down in an effort to avoid the whole “burning up on reentry” problem? 

Let’s see what happens with some simple calculations. We can start with Newton’s Second Law. This gives a relationship between a net force on an object and that object’s acceleration. In one dimension, it looks like this:

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NASA's Voyager 1 resumes sending engineering updates to Earth – Phys.org

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NASA’s Voyager 1 spacecraft is depicted in this artist’s concept traveling through interstellar space, or the space between stars, which it entered in 2012. Credit: NASA/JPL-Caltech

For the first time since November, NASA’s Voyager 1 spacecraft is returning usable data about the health and status of its onboard engineering systems. The next step is to enable the spacecraft to begin returning science data again. The probe and its twin, Voyager 2, are the only spacecraft to ever fly in interstellar space (the space between stars).

Voyager 1 stopped sending readable science and engineering data back to Earth on Nov. 14, 2023, even though mission controllers could tell the was still receiving their commands and otherwise operating normally. In March, the Voyager engineering team at NASA’s Jet Propulsion Laboratory in Southern California confirmed that the issue was tied to one of the spacecraft’s three onboard computers, called the flight data subsystem (FDS). The FDS is responsible for packaging the science and engineering data before it’s sent to Earth.

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The team discovered that a responsible for storing a portion of the FDS memory—including some of the FDS computer’s software code—isn’t working. The loss of that code rendered the science and engineering data unusable. Unable to repair the chip, the team decided to place the affected code elsewhere in the FDS memory. But no single location is large enough to hold the section of code in its entirety.

So they devised a plan to divide affected the code into sections and store those sections in different places in the FDS. To make this plan work, they also needed to adjust those code sections to ensure, for example, that they all still function as a whole. Any references to the location of that code in other parts of the FDS memory needed to be updated as well.

NASA’s Voyager 1 resumes sending engineering updates to Earth
After receiving data about the health and status of Voyager 1 for the first time in five months, members of the Voyager flight team celebrate in a conference room at NASA’s Jet Propulsion Laboratory on April 20. Credit: NASA/JPL-Caltech

The team started by singling out the responsible for packaging the spacecraft’s engineering data. They sent it to its new location in the FDS memory on April 18. A radio signal takes about 22.5 hours to reach Voyager 1, which is over 15 billion miles (24 billion kilometers) from Earth, and another 22.5 hours for a signal to come back to Earth. When the mission flight team heard back from the spacecraft on April 20, they saw that the modification had worked: For the first time in five months, they have been able to check the health and status of the spacecraft.

During the coming weeks, the team will relocate and adjust the other affected portions of the FDS software. These include the portions that will start returning science data.

Voyager 2 continues to operate normally. Launched over 46 years ago, the twin Voyager spacecraft are the longest-running and most distant spacecraft in history. Before the start of their interstellar exploration, both probes flew by Saturn and Jupiter, and Voyager 2 flew by Uranus and Neptune.

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Osoyoos commuters invited to celebrate Earth Day with the Leg Day challenge – Oliver/Osoyoos News – Castanet.net

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Osoyoos commuters can celebrate Earth Day as the Town joins in on a national commuter challenge known as “Leg Day,” entering a chance to win sustainable transportation prizes.

The challenge, from Earth Day Canada, is to record 10 sustainable commutes taken without a car.

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“Cars are one of the biggest contributors to gas emissions in Canada,” reads an Earth Day Canada statement. “That’s why, Earth Day Canada is launching the national Earth Day is Leg Day Challenge.”

So far, over 42.000 people have participated in the Leg Day challenge.

Participants could win an iGo electric bike, public transportation for a year, or a gym membership.

The Town of Osoyoos put out a message Monday promoting joining the national program.

For more information on the Leg Day challenge click here.

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Early bird may dodge verticillium woes in potatoes – Manitobe Co-Operator

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Verticillium wilt is a problem for a lot of crops in Manitoba, including canola, sunflowers and alfalfa.

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Field stress can translate to potato skin flaws.

In potatoes, the fungus Verticillium dahlia is the main cause of potato early die complex. In a 2021 interview with the Co-operator, Mario Tenuta, University of Manitoba soil scientist and main investigator with the Canadian Potato Early Dying Network, suggested the condition can cause yield loss of five to 20 per cent. Other research from the U.S. puts that number as high as 50 per cent.

It also becomes a marketing issue when stunted spuds fall short of processor preferences.

Verticillium in potatoes can significantly reduce yield and, being soil-borne, is difficult to manage.

Preliminary research results suggest earlier planting of risk-prone fields could reduce losses, in part due to colder soil temperatures earlier in the season.

Unlike other potato fungal issues that can be addressed with foliar fungicide, verticillium hides in the soil.

“Commonly we use soil fumigation and that’s very expensive,” said Julie Pasche, plant pathologist with North Dakota State University.

There are options. In 2017, labels expanded for the fungicide Aprovia, Syngenta’s broad-spectrum answer for leaf spots or powdery mildews in various horticulture crops. In-furrow verticillium suppression for potatoes was added to the label.

There has also been interest in biofumigation. Mustard has been tagged as a potential companion crop for potatoes, thanks to its production of glucosinolate and the pathogen- and pest-inhibiting substance isothiocyanate.

Last fall, producers heard that a new, sterile mustard variety specifically designed for biofumigation had been cleared for sale in Canada, although seed supplies for 2024 are expected to be slim. AAC Guard was specifically noted for its effectiveness against verticillium wilt.

Timing is everything

Researchers at NDSU want to study the advantage of natural plant growth patterns.

“What we’d like to look at are other things we can do differently, like verticillium fertility management and water management, as well as some other areas and how they may be affected by planting date,” Pasche said.

The idea is to find a chink in the fungus’s life cycle.

Verticillium infects roots in the spring. From there, it colonizes the plant, moving through the root vascular tissue and into the stem. This is the cause of in-season vegetative wilting, Pasche noted.

As it progresses, plant cells die, leaving behind tell-tale black dots on dead tissue. Magnification of those dots reveals what look like dark bunches of grapes — tiny spheres containing melanized hyphae, a resting form of the fungus called microsclerotia.

The dark colour comes from melanin, the same pigment found in human skin. This pigmentation protects the microsclerotia from ultraviolet light.

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