China launches first crew to live on new space station

Under bright-blue morning skies, China launched its first crewed space mission in five years Thursday, sending three science-minded military pilots rocketing to a new orbiting station they’re expected to reach around midafternoon.

The astronauts, already wearing their spacesuits, were seen off by space officials, other uniformed military personnel and a crowd of children waving flowers and flags and singing patriotic songs. The three gave final waves to a crowd of people waving flags, then entered the elevator to take them to the spaceship at the Jiuquan launch center in northwestern China.

The astronauts are traveling in the Shenzhou-12 spaceship launched by a Long March-2F Y12 rocket that blasted off shortly after the target time of 9:22 a.m. (0122 GMT) with near-perfect visibility at the launch center on the edge of the Gobi Desert.

The two veteran astronauts and a newcomer making his first space flight are scheduled to stay three months in the Tianhe, or Heavenly Harmony, conducting experiments, testing equipment and preparing the station for expansion before two laboratory modules are launched next year.

The rocket dropped its boosters about two minutes into the flight followed by the coiling surrounding Shenzhou-12 at the top of the rocket. After about 10 minutes it separated from the rocket’s upper section, extended its solar panels and shortly afterward entered orbit.

About a half-dozen adjustments will take place over the next four to six hours to line up the spaceship for docking with the Tianhe at about 4 p.m. (0800 GMT), the mission’s deputy chief designer, Gao Xu, told state broadcaster CCTV.

The travel time is down from the two days it took to reach China’s earlier experimental space stations, a result of a “great many breakthroughs and innovations” Gao said.

“So the astronauts can a have a good rest in the space which should make them less tired,” Gao said.

Other improvements include an increase in the number of automated and remote-controlled systems that should “significantly lessen the pressure on the astronauts,” Gao said.

The mission brings to 14 the number of astronauts China has launched into space since its first crewed mission in 2003, becoming only the third country after the former Soviet Union and the United States to do so on its own. Two astronauts on those past missions were women, and while this first station crew is all male, women are expected to be part of future station crews.

The mission is the third of 11 planned through next year to add the additional sections to the station and send up crews and supplies. A fresh three-member crew and a cargo ship with supplies will be sent in three months.

China is not a participant in the International Space Station, largely as a result of U.S. objections to the Chinese programs secrecy and close military ties. However, China has been stepping up cooperation with Russia and a host of other countries, and its station may continue operating beyond the International Space Station, which is reaching the end of its functional life.

China landed a probe on Mars last month that carried a rover, the Zhurong, and earlier landed a probe and rover on the moon’s less explored far side and brought back the first lunar samples by any country’s space program since the 1970s.

After the Tianhe was launched in April, the rocket that carried it into space made an uncontrolled reentry to Earth, though China dismissed criticism of the potential safety hazard. Usually, discarded rocket stages reenter the atmosphere soon after liftoff, normally over water, and don’t go into orbit.

The rocket used Thursday is of a different type and the components that will reenter are expected to burn up long before they could be a danger, said Ji Qiming, assistant director of the China Manned Space Agency.

NATO nations ready to jointly respond to attacks in space

NATO leaders on Monday expanded the use of their all for one, one for all, mutual defense clause to include a collective response to attacks in space.

Article 5 of NATO’s founding treaty states that an attack on any one of the 30 allies will be considered an attack on them all. Until now, it’s only applied to more traditional military attacks on land, sea, or in the air, and more recently in cyberspace.

In a summit statement, the leaders said they “consider that attacks to, from, or within space” could be a challenge to NATO that threatens “national and Euro-Atlantic prosperity, security, and stability, and could be as harmful to modern societies as a conventional attack.”

“Such attacks could lead to the invocation of Article 5. A decision as to when such attacks would lead to the invocation of Article 5 would be taken by the North Atlantic Council on a case-by-case basis,” they said.

Around 2,000 satellites orbit the earth, over half operated by NATO countries, ensuring everything from mobile phone and banking services to weather forecasts. Military commanders rely on some of them to navigate, communicate, share intelligence and detect missile launches.

In December 2019, NATO leaders declared space to be the alliance’s “fifth domain” of operations, after land, sea, air and cyberspace. Many member countries are concerned about what they say is increasingly aggressive behavior in space by China and Russia.

Around 80 countries have satellites, and private companies are moving in, too. In the 1980s, just a fraction of NATO’s communications was via satellite. Today, it’s at least 40%. During the Cold War, NATO had more than 20 stations, but new technologies mean the world’s biggest security organization can double its coverage with a fifth of that number.

NATO’s collective defense clause has only been activated once, when the members rallied behind the United States following the Sept. 11, 2001, attacks.

Former President Donald Trump raised deep concern among U.S. allies, notably those bordering Russia like Estonia, Latvia, Lithuania and Poland, when he suggested that he might not rally to their side if they didn’t boost their defense budgets.

President Joe Biden has been trying to reassure them since taking office and has used the summit, his first at NATO, as a formal opportunity to underline America’s commitment to its European allies and Canada.

Biden said Monday that Article 5 is “a sacred obligation” among allies. “I just want all of Europe to know that the United States is there,” he said. “The United States is there.”

Lockheed Martin gets $1 billion contract for operations of SBIRS ground systems

WASHINGTON — Lockheed Martin received a $1 billion contract to operate and maintain the ground control systems of the U.S. military’s Space Based Infrared System geostationary satellites, the U.S. Space Force announced June 4.

SBIRS is part of the Defense Department’s missile warning network that detects ballistic missile launches. It includes a combination of two infrared sensors in highly elliptical orbit and five satellites in geosynchronous Earth orbit.

Lockheed Martin has been the SBIRS primary contractor since the mid-1990s. The fifth satellite launched May 18. The sixth and final SBIRS is in production and projected to launch in 2022.

The five-year sole-source contract is for operations and maintenance of the SBIRS mission control center at Buckley Air Force Base, Colorado, and other operations centers at Peterson Air Force Base and Greeley Air National Guard Station.

Rob Walker, Lockheed Martin’s director of overhead persistent infrared operations and sustainment, said the contract covers logistics support of existing ground systems and upgrades needed to operate the last two satellites of the SBIRS geosynchronous constellation SBIRS GEO-5 and SBIRS GEO-6.

The Space Force plans to transition to a new network of missile warning satellites called Next-Generation Overhead Persistent Infrared and a new ground system called Future Operationally Resilient Ground Evolution (FORGE). Lockheed Martin is under contract to produce three Next-Gen OPIR geosynchronous satellites, the first of which is projected to launch in 2025.

Walker said this new contract funds work to maintain and sustain infrastructure for the next generation Future Operationally Resilient Ground Evolution ground control system and ensure the SBIRS GEO-5 and GEO-6 satellites are incorporated into the operational constellation.

SpaceX launches tiny critters, solar panels to space station

SpaceX launched thousands of tiny sea creatures to the International Space Station on Thursday, along with a plaque-fighting toothpaste experiment and powerful solar panels.

The 7,300-pound (3,300-kilogram) shipment — which also includes fresh lemons, onions, avocados and cherry tomatoes for the station’s seven astronauts — should arrive Saturday.

SpaceX’s Falcon rocket blasted into the hazy afternoon sky from Kennedy Space Center. The first-stage booster was new for a change, landing on an offshore platform several minutes after liftoff so it can be recycled for a NASA astronaut flight this fall.

The Dragon cargo capsule — also brand new — is delivering the first of three sets of high-tech solar panels designed to bolster the space station’s aging power grid. Astronauts will conduct two spacewalks later this month to help install the two roll-out panels alongside solar wings that have been in continuous operation for 20 years.

More power will be needed to accommodate the growing number of ticket-buying visitors, NASA’s space station program manager, Joel Montalbano, said Wednesday.

The cargo includes samples of saliva and oral bacteria from dental patients that will be treated with toothpaste and mouthwash in an experiment aimed at keeping astronauts’ teeth and gums healthy in space.

“There’s no guarantee that the Earth methods will work in zero gravity,” researcher Jeffrey Ebersole of the University of Nevada Las Vegas said in a statement.

Also headed to the orbiting lab: 20,000 tardigrades, better known as water bears, and 128 bobtail squid, as well as chile pepper plants and cotton seedlings.

Tardigrades can survive in drastic environments on Earth and even in the vacuum of space. Launched frozen, these microscopic extremophiles will be thawed and revived aboard the space station. By identifying the genes behind the animals’ adaptability, scientists hope to better understand the stresses on the human body during long space stays.

The baby bobtail squid are part of a study investigating the relationship between beneficial bacteria and their animal hosts.

This is SpaceX’s 22nd station supply run for NASA. The space agency turned to private companies to transport cargo and astronauts following the shuttles’ retirement a decade ago.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Rocket debris from China’s space station launch is falling back to Earth — but where?

A large Chinese rocket is set to make an uncontrolled reentry back into Earth’s atmosphere, but it is not yet clear exactly where or when the debris will hit our planet.

China’s Long March 5B rocket is “unpredictably” falling back to Earth after launching a part of the new T-shaped Chinese space station on Thursday local time in Wenchang, according to SpaceNews. The 22.5-metric-ton Tianhe space station module is in its correct orbit after separating as planned from the core stage of the rocket, which is now expected to re-enter in a few days or about a week.

“It will be one of the largest instances of uncontrolled reentry of a spacecraft and could potentially land on an inhabited area,” SpaceNews said. That said, the more likely possibility is the core stage will fall in an uninhabited place like Earth’s oceans, which cover 70% of the planet. The odds of a particular individual being hit by space debris are exceedingly low, once estimated at 1 in several trillion.

Plotting the trajectory of this falling rocket stage is difficult, if not impossible because there are too many uncertainties involved in calculating the effect of the atmospheric drag on the core module. Earth’s atmosphere can expand or contract with solar activity, making it hard to estimate exactly when and where the rocket will come down.

“The high speed of the rocket body means it orbits the Earth roughly every 90 minutes and so a change of just a few minutes in reentry time results in reentry point thousands of kilometers away,” SpaceNews said, adding that the object’s orbital inclination of 41.5 degrees means it “passes a little farther north than New York, Madrid and Beijing and as far south as southern Chile and Wellington, New Zealand, and could make its reentry at any point within this area.”

The rocket’s anticipated return numbers among several large debris events of the last few decades, including the Chinese Tiangong space station and Europe’s Gravity field and steady-state Ocean Circulation Explorer (GOCE). That said, most of the debris tends to burn up in the atmosphere and only the very largest pieces would come down to the ground. Launching states also generally try their best to point a returning piece of debris back to Earth and to give estimates for where it may fall.

On Twitter, spaceflight observer and Harvard University astrophysicist Jonathan McDowell plotted the return of the Long March 5B against other large debris events, not least of which was the uncontrolled return of NASA’s 76-ton Skylab space station nearly 42 years ago. Ground controllers were able to steer the space station somewhat over its planned reentry point over the Indian Ocean, but the debris track stretched much further than expected.

“To summarize: this one is bigger than anything recent, but not as big as Skylab and its ilk back in the day,” McDowell said on Twitter of the Long March 5B’s return.

China plans a busy construction schedule on the space station, with state media reporting the construction should be finished by the end of 2022. Much like the International Space Station, the Chinese complex will include several modules, requiring 10 additional launches: two more module launches, four crewed missions and four cargo vessel flights, as reported by China Global Television Network (CGTN).

https://g-dil.com/

SpaceX continues Starlink deployment with latest launch

WASHINGTON — SpaceX continued the deployment of its Starlink broadband megaconstellation May 4 with the second launch of 60 satellites in less than a week.

A Falcon 9 lifted off from Kennedy Space Center’s Launch Complex 39A at 3:01 p.m. Eastern. The rocket’s second stage released its payload of 60 Starlink satellites 64 minutes later.

The rocket’s first stage landed on the center of a droneship in the Atlantic Ocean, completing its ninth flight. The booster previously launched the Telstar 18 Vantage communications satellite, a set of Iridium satellites, and six other Starlink missions. This is the second booster SpaceX has flown nine times.

SpaceX had previously suggested Falcon 9 boosters could fly up to 10 times, but more recently indicated those stages could have longer lifetimes. “I don’t think the number 10 is a magic number,” Hans Koenigsmann, senior adviser for build and flight reliability at SpaceX, said in February. Once a booster reaches the 10-flight milestone, “we will continue to look at that booster and make an assessment whether we can move forward with it.”

That milestone could come soon. The next Falcon 9 Starlink launch, scheduled for no earlier than May 9, is expected to use the other Falcon 9 booster that has flown nine times, most recently in March. The company is using its internal Starlink missions to test the limits of booster reusability.

“There doesn’t seem to be any obvious limit to the reusability of the vehicle,” Elon Musk, chief executive of SpaceX, said at an April 23 NASA press conference after the Crew-2 launch. “We do intend to fly the Falcon 9 booster until we some kind of a failure with the Starlink missions, have that be a life-leader.”

This launch comes less than a week after the previous Falcon 9 Starlink launch April 28. Of the 13 Falcon 9 launches so far this year, 10 have been dedicated to Starlink satellites while the eleventh, the Transporter-1 rideshare mission, carried 10 Starlink satellites, bringing the total number of Starlink satellites launched so far in 2021 to 610. Nearly 1,500 Starlink satellites are currently in orbit.

Space is continuing to build out its Starlink constellation, buoyed by a Federal Communications Commission decision April 27 to approve a license modification sought by SpaceX. That modification will allow SpaceX to operate 2,814 satellites originally planned for orbits between 1,100 and 1,300 kilometers to orbits of 540 to 570 kilometers.

The Starlink service remains in a beta test phase in the United States and several other countries, although Musk suggested last month that the beta test could end as soon as this summer as the constellation is built out.

Siva Bharadvaj, the SpaceX engineer who hosted the webcast of this latest launch, said that “over half a million people have placed an order or put down a deposit for Starlink.” He did not disclose how many people are actively using the service, though.

https://g-dil.com/

Chinese rocket debris to make an uncontrolled reentry: What happened the last time

The almost 100-foot core of China’s Long March 5B rocket is likely to make an uncontrolled reentry at an unknown point in the coming days.

The spacecraft launched Thursday into low Earth orbit from Hainan’s Wenchang Center, ferrying the Tianhe module for the country’s first permanent space station.

However, this is not the first time one of China’s rockets made an uncontrolled descent.

Last May, debris from the same rocket rained down on at least two villages along Africa’s Ivory Coast. In that case, the rocket – which weighs more than 1.8 million pounds when fully fueled – was carrying an experimental crew capsule designed for potential future lunar missions.

The rocket reentered over the Atlantic Ocean at 11:33 a.m. ET on Monday, May 11, 2020.

Photos showed long metal rods that reportedly damaged several buildings in Ivory Coast, though no casualties were reported.

A local infrasound station also recorded what appeared to be rocket debris moving through the atmosphere at supersonic speeds and hitting the ground.

The Verge reported that locals heard sonic booms and saw flashes and falling debris at around the same time that the rocket would have passed overhead.

Newsweek reported that part of the rocket had fallen into the water near West Africa after spending a week in low Earth orbit.

At the time, the U.S. Air Force’s 18th Space Control Squadron said the rocket passed directly over major U.S. cities – including Los Angeles and New York City – on its way down.

It was the largest object to make an uncontrolled descent since the Soviet Union’s 43-ton Salyut-7 space station landed in Argentina in 1991.

The only debris larger than the Salyut-7 space station was NASA’s almost 100-ton Skylab, which fell on a small Australian town in 1979.

Notably, a nuclear-powered Soviet satellite that reentered the atmosphere over northern Canada in 1978 resulted in a $3,000,000 fine for its clean-up over the tundra.

Typically, rocket manufacturers account for falling rocket debris.

The Associated Press contributed to this report.

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It’s not how big your laser is, it’s how you use it. Space law is an important part of the fight against space debris

This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.

Steven Freeland, Professorial Fellow, Bond University / Emeritus Professor of International Law, Western Sydney University, Western Sydney University

Annie Handmer, PhD candidate, School of History and Philosophy of Science, University of Sydney

Space is getting crowded. More than 100 million tiny pieces of debris are spinning in Earth orbit, along with tens of thousands of bigger chunks and around 3,300 functioning satellites.

Large satellite constellations such as Starlink are becoming more common, infuriating astronomers and baffling casual skywatchers. In the coming decade, we may see many more satellites launched than in all of history up to now.

Collisions between objects in orbit are getting harder to avoid. Several technologies for getting space debris out of harm’s way have been proposed, most recently the plan from Australian company Electro Optic Systems (EOS) to use a pair of ground-based lasers to track debris and “nudge” it away from potential collisions or even out of orbit altogether.

Tools like this will be in high demand in coming years. But alongside new technology, we also need to work out the best ways to regulate activity in space and decide who is responsible for what.

EOS’s laser system is just one of a host of “active debris removal” (ADR) technologies proposed over the past decade. Others involve sails, tentacles, nets, claws, harpoons, magnets and foam.

Outside Australia, Japan-based company Astroscale is currently testing its ELSA system for capturing debris with magnets. The British RemoveDEBRIS project has been experimenting with nets and harpoons. The European Space Agency (ESA) is engaged in various debris-related missions including the ClearSpace-1 “space claw”, designed to grapple a piece of debris and drag it down to a lower orbit where the claw and its captured prey will end their lives in a fiery embrace.

Close calls are becoming more common

Space debris poses a very real threat, and interest in ADR technologies is growing rapidly. The ESA estimates there are currently 128 million pieces of debris smaller than 1cm, about 900,000 pieces of debris 1–10cm in length, and around 34,000 pieces larger than 10cm in Earth orbit.

Given the high speed of objects in space, any collision – with debris or a “live” satellite – could create thousands more pieces of debris. These could create more collisions and more debris, potentially triggering an exponential increase in debris called the “Kessler effect”. Eventually we could see a “debris belt” around Earth, making space less accessible.

In recent times, we have seen several “near collisions” in space. In late January 2020, we all watched helplessly as two much larger “dead” satellites – IRAS and GGSE-4 – passed within metres of each other. NASA often moves the International Space Station when it calculates a higher-than-normal risk of collision with debris.

More satellites, more risk

The problem of space debris is becoming more urgent as more large constellations of small satellites are launched. In 2019, the ESA sent one of its Earth-observing satellites on a small detour to avoid a high possibility of a collision with one of SpaceX’s Starlink satellites.

In just the past few days, satellites from One Web and Starlink came perilously close to a collision. If the well-publicised plans of just a few large corporations come to fruition, the number of objects launched into space over the coming years will dwarf by a factor of up to ten times the total number launched over the six decades since the first human-made object (Sputnik 1) was sent into orbit in 1957.

Space law can help

Any feasible technology to alleviate the problem of space debris should be thoroughly explored. At the same time, actively removing debris raises political and legal problems.

Space is an area beyond national jurisdiction. Like the high seas, space is governed through international law. The 1967 Outer Space Treaty and the four other international treaties that followed set out a framework and key principles to guide responsible behaviour.

While the engineers might envisage nets and harpoons, international law is bad news for aspiring space “pirates”. Any space object or part of a space object, functional or not, remains under the jurisdiction of a “State of registry”.

Under international law, to capture, deflect or interfere with a piece of debris would constitute a “national activity in outer space” – meaning the countries that authorised or agreed to the ADR manoeuvre have an international legal responsibility, even if the action is carried out by a private company. In addition, if something goes wrong (as we know, space is hard), a liability regime applies to the “launching States” under the applicable Treaty, which would include those countries involved in the launch of the ADR vehicle.

The rules of the road

Beyond the legal technicalities, debris removal raises complex policy, geopolitical, economic, and social challenges. Whose responsibility is it to remove debris? Who should pay? What rights do non-spacefaring nations have in discussions? Which debris should be preserved as heritage?

And if a State develops the capability to remove or deflect space debris, how can we be sure they won’t use it to remove or deflect another country’s “live” satellites?

Experts are working to recognise and determine the appropriate regulatory “rules of the road”. The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) deals with space governance, and it has had “legal mechanisms relating to space debris mitigation and remediation measures” on its agenda for years. There are already some widely-accepted and practical guidelines for debris mitigation and long-term sustainability of space activities, but each proposed solution brings with it other questions.

In the end, any debris remediation activity will require a negotiated agreement between each of the relevant parties to ensure these legal and other questions are addressed. Eventually, we might see a standardised process emerge, in coordination with an international system of space traffic management.

The future of humanity is inextricably tied to our ability to ensure a viable long-term future for space activities. Developing new debris removal methods, and the legal frameworks to make them usable, are important steps towards finding ways to co-exist with our planet and promote the ongoing safety, security and sustainability of space.

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

New warp drive research dashes faster than light travel dreams, but reveals stranger possibilities

This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.

Sam Baron, Associate professor, Australian Catholic University

In 1994, physicist Miguel Alcubierre proposed a radical technology that would allow faster than light travel: the warp drive, a hypothetical way to skirt around the universe’s ultimate speed limit by bending the fabric of reality.

It was an intriguing idea — even NASA has been researching it at the Eagleworks laboratory — but Alcubierre’s proposal contained problems that seemed insurmountable. Now, a recent paper by US-based physicists Alexey Bobrick and Gianni Martire has resolved many of those issues and generated a lot of buzz.

But while Bobrick and Martire have managed to substantially demystify warp technology, their work actually suggests that faster-than-light travel will remain out of reach for beings like us, at least for the time being.

There is, however, a silver lining: warp technology may have radical applications beyond space travel.

The story of warp drives starts with Einstein’s crowning achievement: general relativity. The equations of general relativity capture the way in which spacetime – the very fabric of reality — bends in response to the presence of matter and energy which, in turn, explains how matter and energy move.

General relativity places two constraints on interstellar travel. First, nothing can be accelerated past the speed of light (around 300,000 km per second). Even travelling at this dizzying speed it would still take us four years to arrive at Proxima Centauri, the nearest star to our Sun.

Second, the clock on a spaceship travelling close to the speed of light would slow down relative to a clock on Earth (this is known as time dilation). Assuming a constant state of acceleration, this makes it possible to travel the stars. One can reach a distant star that is 150 light-years away within one’s lifetime. The catch, however, is that upon one’s return more than 300 years will have passed on Earth.

A new hope

This is where Alcubierre came in. He argued that the mathematics of general relativity allowed for “warp bubbles” — regions where matter and energy were arranged in such a way as to bend spacetime in front of the bubble and expand it to the rear in a way that allowed a “flat” area inside the bubble to travel faster than light.

Read more: Don’t stop me now! Superluminal travel in Einstein’s universe

To get a sense of what “flat” means in this context, note that spacetime is sort of like a rubber mat. The mat curves in the presence of matter and energy (think of putting a bowling ball on the mat). Gravity is nothing more than the tendency objects have to roll into the the dents created by things like stars and planets. A flat region is like a part of the mat with nothing on it.

Such a drive would also avoid the uncomfortable consequences of time dilation. One could potentially make a round trip into deep space and still be greeted by one’s nearest and dearest at home.
A spacetime oddity

How does Alcubierre’s device work? Here discussion often relies on analogies, because the maths is so complex.

Imagine a rug with a cup on it. You’re on the rug and you want to get to the cup. You could move across the rug, or tug the rug toward you. The warp drive is like tugging on spacetime to bring your destination closer.

But analogies have their limits: a warp drive doesn’t really drag your destination toward you. It contracts spacetime to make your path shorter. There’s just less rug between you and the cup when you switch the drive on.

Alcubierre’s suggestion, while mathematically rigorous, is difficult to understand at an intuitive level. Bobrick and Martire’s work is set to change all that.
Starship bloopers

Bobrick and Martire show that any warp drive must be a shell of material in a constant state of motion, enclosing a flat region of spacetime. The energy of the shell modifies the properties of the spacetime region inside it.

This might not sound like much of a discovery, but until now it was unclear what warp drives might be, physically speaking. Their work tells us that a warp drive is, somewhat surprisingly, like a car. A car is also a shell of energy (in the form of matter) that encloses a flat region of spacetime. The difference is that getting inside a car does not make you age faster. That, however, is the kind of thing a warp drive might do.

Using their simple description, Bobrick and Martire demonstrate a method for using Einstein’s general relativity equations to find spacetimes that allow for arrangements of matter and energy that would act as warp bubbles. This gives us a mathematical key for finding and classifying warp technologies.

Their work manages to address one of the core problems for warp drives. To make the equations balance, Alcubierre’s device runs on “negative energy” – but we are yet to discover any viable sources of negative energy in the real world.

Worse, the negative energy requirements of Alcubierre’s device are immense. By some estimates, the entire energy in the known universe would be needed (though later work brings the number down a bit).

Bobrick and Martire show a warp drive could be made from positive energy (i.e. “normal” energy) or from a mixture of negative and positive energy. That said, the energy requirements would still be immense.

If Bobrick and Martire are right, then a warp drive is just like any other object in motion. It would be subject to the universal speed limit enforced by general relativity after all, and it would need some kind of conventional propulsion system to make it accelerate.

The news gets worse. Many kinds of warp drive can only modify the spacetime inside in a certain way: by slowing down the clock of the passenger in exactly the way that makes a trip into deep space a problem.

Bobrick and Martire do show that some warp drives could travel faster than light, but only if they are created already travelling at that speed – which is no help for any ordinary human hoping for a bit of interstellar tourism.

The end game

Remember that a warp drive can modify the region of flat spacetime it encloses. It can, in particular, speed up or slow down a clock inside the drive.

Consider what it would mean to have such an object available. Want to put someone with a terminal illness on ice? Stick them in a warp drive and slow their clock down. From their perspective, a few years will pass, while a hundred years will pass on Earth — time enough to find a cure.

Want to grow your crops overnight? Stick them in a warp drive and speed the clock up. A few days will pass for you, and a few weeks will pass for your seedlings.

There are even more exotic possibilities: by rotating the spacetime inside a drive one may be able to produce a battery capable of holding huge amounts of energy.

Faster-than-light travel remains a distant dream. But warp technology would be revolutionary in its own right.

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

Artificial intelligence is learning how to dodge space junk in orbit

An AI-driven space debris-dodging system could soon replace expert teams dealing with growing numbers of orbital collision threats in the increasingly cluttered near-Earth environment.

Every two weeks, spacecraft controllers at the European Space Operations Centre (ESOC) in Darmstadt, Germany, have to conduct avoidance manoeuvres with one of their 20 low Earth orbit satellites, Holger Krag, the Head of Space Safety at the European Space Agency (ESA) said in a news conference organized by ESA during the 8th European Space Debris Conference held virtually from Darmstadt Germany, April 20 to 23. There are at least five times as many close encounters that the agency’s teams monitor and carefully evaluate, each requesting a multi-disciplinary team to be on call 24/7 for several days.

“Every collision avoidance manoeuvre is a nuisance,” Krag said. “Not only because of fuel consumption but also because of the preparation that goes into it. We have to book ground-station passes, which costs money, sometimes we even have to switch off the acquisition of scientific data. We have to have an expert team available round the clock.”

The frequency of such situations is only expected to increase. Not all collision alerts are caused by pieces of space debris. Companies such as SpaceX, OneWeb and Amazon are building megaconstellations of thousands of satellites, lofting more spacecraft into orbit in a single month than used to be launched within an entire year only a few years ago. This increased space traffic is causing concerns among space debris experts. In fact, ESA said that nearly half of the conjunction alerts currently monitored by the agency’s operators involve small satellites and constellation spacecraft.

ESA, therefore, asked the global Artificial Intelligence community to help develop a system that would take care of space debris dodging autonomously or at least reduce the burden on the expert teams.

“We made a large historic data set of past conjunction warnings available to a global expert community and tasked them to use AI [Artificial Intelligence] to predict the evolution of a collision risk of each alert over the three days following the alert,” Rolf Densing, Director of ESA Operations said in the news conference.

“The results are not yet perfect, but in many cases, AI was able to replicate the decision process and correctly identify in which cases we had to conduct the collision avoidance manoeuvre.”

The agency will explore newer approaches to AI development, such as deep learning and neural networks, to improve the accuracy of the algorithms, Tim Flohrer, the Head of ESA’s Space Debris Office told Space.com.

“The standard AI algorithms are trained on huge data sets,” Flohrer said. “But the cases when we had actually conducted manoeuvres are not so many in AI terms. In the next phase we will look more closely into specialised AI approaches that can work with smaller data sets.”

For now, the AI algorithms can aid the ground-based teams as they evaluate and monitor each conjunction alert, the warning that one of their satellites might be on a collision course with another orbiting body. According to Flohrer, such AI-assistance will help reduce the number of experts involved and help the agency deal with the increased space traffic expected in the near future. The decision whether to conduct an avoidance manoeuvre or not for now still has to be taken by a human operator.

“So far, we have automated everything that would require an expert brain to be awake 24/7 to respond to and follow up the collision alerts,” said Krag. “Making the ultimate decision whether to conduct the avoidance manoeuvre or not is the most complex part to be automated and we hope to find a solution to this problem within the next few years.”

Ultimately, Densing added, the global community should work together to create a collision avoidance system similar to modern air-traffic management, which would work completely autonomously without the humans on the ground having to communicate.

“In air traffic, they are a step further,” Densing said. “Collision avoidance manoeuvres between planes are decentralised and take place automatically. We are not there yet, and it will likely take a bit more international coordination and discussions.”

Not only are scientific satellites at risk of orbital collisions, but spacecraft like SpaceX’s Crew Dragon could be affected as well. Recently, Crew Dragon Endeavour, with four astronauts on board, reportedly came dangerously close to a small piece of debris on Saturday, April 24, during its cruise to the International Space Station. The collision alert forced the spacefarers to interrupt their leisure time, climb back into their space suits and buckle up in their seats to brace for a possible impact.

According to ESA, about 11,370 satellites have been launched since 1957, when the Soviet Union successfully orbited a beeping ball called Sputnik. About 6,900 of these satellites remain in orbit, but only 4,000 are still functioning.