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

B.C. looking at easing restrictions for sports, religious services in the ‘coming weeks’ – Saanich News

Published

 on


Restrictions that have seen British Columbians heavily limit their interactions for months could be loosened in the coming weeks, according to provincial health officer Dr. Bonnie Henry.

In a press conference Monday (March 8) where she announced more than 1,400 new cases over the weekend, Henry said that with more and more vaccine approved and the immunization program ramping up, restrictions could be reconsidered in the spring.

“In the weeks ahead we can start to look at this modified return of some of the activities that have been on pause for the last months of winter,” she said.

“In the coming weeks we hope to see the return of sports and religious ceremonies.”

Henry said health provincials are working with religious leaders to bring back in-person worship, but warned that it will be a phased approach.

There are several religious holidays coming up, including Easter, Passover, Vaisakhi and Ramadan.

“How do we make sure that people can celebrate those things safely? And yes that’s our plan,” she said, but noted that B.C. is still in the middle of a pandemic.

“It may not be what Easter celebrations have been in the past, but they will be celebrations. Unless things go off the rails we are planning for them to be in person.”

Henry said that as the weather gets warmer, and people can spend more time outside, gatherings could return.

“What we are looking at, as we head into March break, spring break, at the end of this week and into this week is seeing the return of things like gatherings outside, where it’s safer, activities outside that we can do in groups with precautions in place,” Henry said.

“Small groups that we can do for games, summer camps, spring camps and safe small groups with masks and safety precautions in place.”

However, she warned that it is not yet time for large-scale events and gatherings.

“We will be in a much different place by the time we head into summer,” she said.

“[But] we’re not yet in a place where we can go back to our pre pandemic gatherings.”

Henry also said the province was looking at how safe travel within B.C. could return.

“The risk is different in different communities in this province and we need to be mindful of that.”

READ MORE: B.C.’s COVID-19 cases: 545 Saturday, 532 Sunday, 385 Monday


@katslepian

katya.slepian@bpdigital.ca

Like us on Facebook and follow us on Twitter.

Want to support local journalism during the pandemic? Make a donation here.

Coronavirus

Get local stories you won’t find anywhere else right to your inbox.
Sign up here

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Alluxa's Optical Filters Landed on Mars – Novus Light Today – Novus Light Technologies Today

Published

 on



Alluxa, Inc., a global leader in high-performance optical coatings and filters and thin-film deposition technologies, developed specialty optical filters used aboard the Perseverance Rover, which landed safely on Mars on February 18, 2021. Alluxa’s special notch filter is optimized for high performance over a wide angle range in order to provide in-band light to the Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals (SHERLOC)  imager.

Alluxa’s filters help enable non-contact detection and characterization of organics and minerals on Mar’s surface. Developed in conjunction with NASA’s Jet Propulsion Lab in Pasadena, California, the SHERLOC instrument, part of the Perseverance payload, is a Deep UV (DUV) resonance Raman and fluorescence spectrometer that will scan for past life on Mars and help identify rock samples for possible return to Earth.

SHERLOC operates at the end of rover’s robotic arm, using two distinct detection modes that include two types of UV light spectroscopy, plus a versatile camera. According to Luther Beegle, principal scientist and investigator at NASA Jet Propulsion Laboratory, “It can detect an important class of carbon molecules with high sensitivity, and it also identifies minerals that provide information about ancient aqueous environments.”

Mike Scobey, Chief Executive Officer at Alluxa, notes, “All of us at Alluxa are delighted to have worked hand-in-hand with JPL to develop a specialized notch filter with ultra high transmission, which will aid in groundbreaking discoveries on Mars via the Perseverance Rover’s SHERLOC imager. We are proud to have been part of this historic mission.”                    

PHOTO CAPTION:  This illustration depicts NASA’s Perseverance rover operating on the surface of Mars.  Perseverance landed at the Red Planet’s Jezero Crater on Feb. 18, 2021. Credit: NASA/JPL-Caltech

Let’s block ads! (Why?)



Source link

Continue Reading

Science

"We are in the worst situation during this pandemic" – Dr DeMille – Net Newsledger

Published

 on


Assume that COVID is There!

Thunder Bay – COVID-19 Update – The surge in COVID-19 numbers has Thunder Bay District topping the province with the most cases per 100,000 of population.

There are reports of COVID-19 at the Real Canadian Superstore and at Walmart locations in Thunder Bay. Staff members have been confirmed with the virus.

“This virus is having an easy time spreading from one person to the next,” says Dr. DeMille. Many times people are spreading the virus without knowing they have the virus.

“We are seeing people going out, hanging out with others even before they know they have COVID,” added DeMille.

This evening Thunder Bay District Health Unit (TBDHU) and Schoolhouse Playcare Centre (Ecole Elsie MacGill School location) confirm that an outbreak of COVID-19 has been declared at the facility in Thunder Bay.

Consistent with provincial guidelines, an outbreak is declared in a child care centre when there are two or more COVID-19 cases that can be linked within the setting. At this time, one additional individual associated with the child care centre has tested positive for COVID-19. This individual is deemed to have acquired the infection in the facility.

The announcement of the outbreak at Schoolhouse Playcare Centre (Ecole Elsie MacGill) does not mean the child care centre is closing. Only those identified as having had close contact with the case will be excluded from attending. In collaboration with the Schoolhouse Playcare Centre (Ecole Elsie MacGill) TBDHU will continue to monitor and assess the situation until the full risk period has passed.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending