Connect with us

Science

Here's What Really Happened to Those 2 Satellites Projected to Crash in Earth Orbit – ScienceAlert

Published

 on


It appears we have missed another close call between two satellites – but how close did we really come to a catastrophic event in space?

It all began with a series of tweets from LeoLabs, a company that uses radar to track satellites and debris in space. It predicted that two obsolete satellites orbiting Earth had a 1 in 100 chance of an almost direct head-on collision at 9:39am AEST on 30 January (23:39 UTC, January 29) with potentially devastating consequences.

LeoLabs estimated that the satellites could pass within 15-30 meters (50-100 feet) of one another. Neither satellite could be controlled or moved. All we could do was watch whatever unfolded above us.

Collisions in space can be disastrous and can send high-speed debris in all directions. This endangers other satellites, future launches, and especially crewed space missions.

As a point of reference, NASA often moves the International Space Station when the risk of collision is just 1 in 100,000. Last year the European Space Agency moved one of its satellites when the likelihood of collision with a SpaceX satellite was estimated at 1 in 50,000.

However, this increased to 1 in 1,000 when the US Air Force, which maintains perhaps the most comprehensive catalogue of satellites, provided more detailed information.

Following LeoLabs’ warning, other organisations such as the Aerospace Corporation began to provide similarly worrying predictions. In contrast, calculations based on publicly available data were far more optimistic. Neither the US Air Force nor NASA issued any warning.

This was notable, as the United States had a role in the launch of both satellites involved in the near-miss. The first is the Infrared Astronomical Satellite (IRAS), a large space telescope weighing around a tonne and launched in 1983.

It successfully completed its mission later that year and has floated dormant ever since.

The second satellite has a slightly more intriguing story. Known as GGSE-4, it is a formerly secret government satellite launched in 1967. It was part of a much larger project to capture radar emissions from the Soviet Union. This particular satellite also contained an experiment to explore ways to stabilise satellites using gravity.

Weighing in at 83 kilograms (182 pounds), it is much smaller than IRAS, but it has a very unusual and unfortunate shape. It has an 18 meter (60 foot) protruding arm with a weight on the end, thus making it a much larger target.

Almost 24 hours later, LeoLabs tweeted again. It downgraded the chance of a collision to 1 in 1,000, and revised the predicted passing distance between the satellites to 13-87 meters (43-285 feet). Although still closer than usual, this was a decidedly smaller risk.

But less than 15 hours after that, the company tweeted yet again, raising the probability of collision back to 1 in 100, and then to a very alarming 1 in 20 after learning about the shape of GGSE-4.

The good news is that the two satellites appear to have missed one another. Although there were a handful of eyewitness accounts of the IRAS satellite appearing to pass unharmed through the predicted point of impact, it can still take a few hours for scientists to confirm that a collision did not take place.

LeoLabs has since confirmed it has not detected any new space debris.

But why did the predictions change so dramatically and so often? What happened?

Tricky situation

The real problem is that we don’t really know precisely where these satellites are. That requires us to be extremely conservative, especially given the cost and importance of most active satellites, and the dramatic consequences of high-speed collisions.

The tracking of objects in space is often called Space Situational Awareness, and it is a very difficult task. One of the best methods is radar, which is expensive to build and operate. Visual observation with telescopes is much cheaper but comes with other complications, such as weather and lots of moving parts that can break down.

Another difficulty is that our models for predicting satellites’ orbits don’t work well in lower orbits, where drag from Earth’s atmosphere can become a factor.

There is yet another problem. Whereas it is in the best interest of commercial satellites for everyone to know exactly where they are, this is not the case for military and spy satellites. Defence organisations do not share the full list of objects they are tracking.

This potential collision involved an ancient spy satellite from 1967. It is at least one that we can see. Given the difficulty of just tracking the satellites that we know about, how will we avoid satellites that are trying their hardest not to be seen?

In fact, much research has gone into building stealth satellites that are invisible from Earth. Even commercial industry is considering making satellites that are harder to see, partly in response to astronomers’ own concerns about objects blotting out their view of the heavens.

SpaceX is considering building “dark satellites” the reflect less light into telescopes on Earth, which will only make them harder to track.

What should we do?

The solution starts with developing better ways to track satellites and space debris. Removing the junk is an important next step, but we can only do that if we know exactly where it is.

Western Sydney University is developing biology-inspired cameras that can see satellites during the day, allowing them to work when other telescopes cannot. These sensors can also see satellites when they move in front of bright objects like the Moon.

There is also no clear international space law or policy, but a strong need for one. Unfortunately, such laws will be impossible to enforce if we cannot do a better job of figuring out what is happening in orbit around our planet.

Gregory Cohen, Associate Professor, Western Sydney University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Scientists produce diamonds in minutes at room temperature – MINING.com

Published

 on


“Natural diamonds are usually formed over billions of years, about 150 kilometres deep in the Earth where there are high pressures and temperatures above 1,000 degrees Celsius,”  Jodie Bradby, professor at The Australian National University and one of the authors of the study, said in a media statement.

“The twist in this story is how we apply the pressure. As well as very high pressures, we allow the carbon to also experience something called ‘shear’ – which is like a twisting or sliding force. We think this allows the carbon atoms to move into place and form Lonsdaleite and regular diamond.” 

The RMIT team’s pictures showed that the regular diamonds only form in the middle of these Lonsdaleite veins under this new method. (Image courtesy of the Royal Melbourne Institute of Technology).

To observe and understand how this process works, the researchers used advanced electron microscopy techniques to capture solid and intact slices from the experimental samples to create snapshots of how the two types of diamonds formed.

The pictures showed that the regular diamonds only form in the middle of Lonsdaleite veins under this new method.

“Seeing these little ‘rivers’ of Lonsdaleite and regular diamond for the first time was just amazing and really helps us understand how they might form,” Dougal McCulloch, the study’s lead author and a professor at the Royal Melbourne Institute of Technology, said. 

According to the scientists, Lonsdaleite has the potential to be used for cutting through ultra-solid materials on mining sites. As such, they said that creating more of this rare diamond is the long-term aim of their work.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Siemens, Deutsche Bahn launch local hydrogen trains trial – The Guardian

Published

 on


MUNICH (Reuters) – Siemens Mobility and Deutsche Bahn have started developing hydrogen-powered fuel cell trains and a filling station which will be trialled in 2024 with view to replace diesel engines on German local rail networks.

The prototype, to be built by Siemens, is based on electric railcar Mireo Plus which will be equipped with fuel cells to turn hydrogen and oxygen into electricity on board, and with a battery, both companies said.

Siemens mobility chief executive Michael Peter told Reuters the train combined the possibility to be fed by three sources in a modular system – either by the battery, the fuel cell or even existing overhead lines, depending on where it would run.

German railway operator Deutsche Bahn has not electrified 40% of its 33,000 kilometre (km) long network, on which it runs 1,300 fossil-fuel emitting diesel locomotives.

Rail transport must be decarbonised over the long-term under European Union and national climate targets.

“Our hydrogen trains are able to replace diesel-fuelled trains in the long term,” Peter said.

The new prototype will be fuelled within 15 minutes, have a range of 600 km and a top speed of 160 km/hour.

It will be tested between Tuebingen, Horb and Pforzheim in Baden Wuerttemberg state.

The main target market are operators of regional networks that typically re-order lots of 10 to 50 trains, Peter said.

“We see a market potential of 10,000-15,000 trains in Europe that will need to be replaced over the next 10-15 years, with 3,000 alone in Germany,” he said.

Each train will cost between five and 10 million euros ($5.9-$11.9 million), creating a market potential of 50-150 billion euros overall.

The Berlin government expects green hydrogen to become competitive with fossil fuels over the long term and to play a key role in decarbonising industry, heating and transport.

(Reporting by Joern Poltz in Munich and Vera Eckert in Frankfurt, editing by David Evans)

Let’s block ads! (Why?)



Source link

Continue Reading

Science

The impossible choice Canada’s seniors face this winter – 95.7 News

Published

 on


In today’s Big Story podcast, we want elderly Canadians, who are heightened risk from COVID-19, to be safe. For much of the past eight months, that has meant hundreds of thousands of grandparents haven’t seen their grandkids, parents haven’t seen their children, or their siblings — and for many of them, this has harmed them as much as a bout with the virus might.

We all want our elderly loved ones to be around forever, but even forgetting about COVID-19, they won’t be. And as they face another four to six months without much contact or support, many of them are wondering if they might not choose to take the risk with the time they have left.

GUEST: Christina Frangou, science and health writer

You can subscribe to The Big Story podcast on Apple Podcasts, Google and Spotify

You can also find it at thebigstorypodcast.ca.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending