Since time immemorial, humans around the world have gazed up in wonder at the night sky. The starry night sky has not only inspired countless works of music, art, and poetry but has also played an important role in timekeeping, navigation and agricultural practices in many traditions.
For many cultures, the night sky, with its stars, planets and the Milky Way, is considered just as important a part of the natural environment as the forests, lakes and mountains below. Countless people around the world gaze at the night sky: not only amateur and professional astronomers, but also casual observers who enjoy looking up at the stars to contemplate our place in the cosmos.
However, the night sky is changing. Not only is ground-based light pollution increasing rapidly, but growing numbers of satellites and space debris in orbit around Earth are also impacting the night sky.
Earlier research showed that satellites and space debris may increase the overall brightness of the night sky. In a new paper in Nature Astronomy, my colleagues and I applied this knowledge to predicting the performance of a major astronomical sky survey. We found this phenomenon may make the survey 7.5 percent less efficient and US$21.8 million (roughly Rs. 180 crore) more expensive.
A brighter sky
As a cultural astronomer, I am interested in the role of the night sky in cultural traditions around the world. In particular, I am interested in how light pollution and increasing satellite numbers affect different communities.
The number of satellites in orbit is growing rapidly. Since 2019, the number of functional satellites in orbit has more than doubled to around 7,600. The increase is mostly due to SpaceX and other companies launching large groups of satellites to provide high-speed internet communications around the world.
By the end of this decade, we estimate, there may be 100,000 satellites in orbit around the Earth. Collisions that generate space debris are more likely as space fills with new satellites. Other sources of debris include the intentional destruction of satellites in space warfare tests.
Increasing numbers of satellites and space debris reflect ever more sunlight towards the night side of Earth. This will almost certainly change the appearance of the night sky and make it harder for astronomers to do research.
One way satellites impact astronomy is by appearing as moving points of light, which show up as streaks across astronomers’ images. Another is by increasing diffuse night sky brightness. This means all the satellites that are too dim or small to be seen individually, as well as all the small bits of space debris, still reflect sunlight, and their collective effect is to make the night sky appear less dark.
Hard times for astronomers
In our research, we present the first published calculations of the aggregate effects of satellites and space debris in low-Earth orbit on major ground-based astronomy research facilities.
We looked at the effect on the planned large-scale survey of the night sky to be carried out at the Vera Rubin Observatory starting in 2024. We found that, by 2030, reflected light from objects in low-Earth orbit will likely increase the diffuse background brightness for this survey by at least 7.5 percent compared to an unpolluted sky.
This would diminish the efficiency of this survey by 7.5 percent as well. Over the ten-year lifetime of the survey, we estimate this would add some $21.8 million (roughly Rs. 180 crore) to the total project cost.
Brighter night skies mean longer exposures through telescopes are needed to see distant objects in the cosmos. This will mean that for projects with a fixed amount of observing time, less science will be accomplished, and there will be increased competition for telescope access.
In addition, brighter night skies will also reduce the detection limits of sky surveys, and dimmer objects may not be detected, resulting in missed research opportunities.
Some astrophysical events are rare and if researchers are unable to view them when they occur, there might not be an opportunity to easily see a given event again during a survey’s operational period. One example of faint objects is near-Earth objects – comets and asteroids in orbits close to Earth. Brighter night skies make it more likely such potentially hazardous objects may remain undetected.
A dramatic and unprecedented transformation
Increases in diffuse night sky brightness will also change how we see the night sky with the unaided eye. As the human eye cannot resolve individual small objects as well as a telescope can, an increase in satellites and space debris will create an even greater increase in the apparent brightness of the night sky. (When using a telescope or binoculars, one would be able to make out more of the dimmer satellites individually.) The projected increase in night sky brightness will make it increasingly difficult to see fainter stars and the Milky Way, both of which are important in various cultural traditions. Unlike “ground-based” light pollution (which tends to be the worst near large cities and heavily populated areas), the changes to the sky will be visible from essentially everywhere on Earth’s surface.
Our models give us a conservative lower limit for a likely increase in night sky brightness. If numbers of satellites and space debris continue to grow at the expected rate, the impacts will be even more pronounced.
As we note in our paper, “we are witnessing a dramatic, fundamental, and perhaps semi-permanent transformation of the night sky without historical precedent and with limited oversight”. Such a transformation will have profound consequences for professional astronomy as well as for anyone who wishes to view an unpolluted night sky.
ISRO Chairman ‘Confident’ Chandrayan-3 Moon Mission Will Launch in July
Indian Space Research Organisation (ISRO) Chairman S Somnath on Monday said that the Chandrayaan-3- the third edition of India’s mission to the moon- will be launched this July.
Chandrayaan-3 is a follow-on mission to Chandrayaan-2 to demonstrate end-to-end capability in safe landing and roving on the lunar surface.
“I am very confident…” said Somnath today on the lunar mission.
The ISRO chairman was speaking after the space agency successfully placed the NVS-01, the first of the second-generation satellite series, into geosynchronous transfer orbit. The Geosynchronous Satellite Launch Vehicle deployed the NVS-01 navigation satellite from the second launch pad at the Satish Dhawan Space Centre (SDC SHAR) in Sriharikota in Andhra Pradesh.
Speaking to ANI, Somanath said, “The lesson is very simple. Learn from the past, and do what is possible with your capacity. Failures may happen. There are a thousand reasons for a rocket to fail. Even today, this mission could have failed. But we have to do what is needed to be done”.
Meanwhile, the Chandraayan-3 mission consists of an indigenous lander module a propulsion module and a rover with an objective of developing and demonstrating new technologies required for Inter planetary missions.
According to ISRO, the three mission objectives of the Chandrayaan-3 are- to demonstrate safe and soft landing on lunar Surface; to demonstrate Rover roving on the moon and to conduct in-situ scientific experiments.
It will be launched by the LVM3 rocket from SDSC SHAR centre in Sriharikota. The propulsion module will carry the lander and rover configuration till 100 km lunar orbit, according to ISRO.
The propulsion module has Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and Polari metric measurements of Earth from the lunar orbit.
The Lander will have the capability to soft land at a specified lunar site and deploy the Rover which will carry out in-situ chemical analysis of the lunar surface during the course of its mobility. The Lander and the Rover have scientific payloads to carry out experiments on the lunar surface.
The main function of the Propulsion Module is to carry the Lander Module from launch vehicle injection till final lunar 100 km circular polar orbit and separate the Lander Module from the Propulsion Module.
Apart from this, the Propulsion Module also has one scientific payload as a value addition which will be operated post separation of Lander Module.
The launcher identified for Chandrayaan-3 is GSLV-Mk3 which will place the integrated module in an Elliptic Parking Orbit (EPO) of size 170 x 36500 km.
The Chandrayaan is an ongoing series of lunar space exploration programme of the ISRO. Chandrayaan-1, the first lunar probe of ISRO, in 2008-09 found water on the moon. The Chandrayaan-2 was launched in July 2019 and successfully inserted into orbit in August 2019. However, minutes its lander crash-landed on the moon after losing communication with the ground stations.
Earlier in the day, the ISRO Chairman Somnath congratulated the whole ISRO team after the successful launch of NVS-01.
“I would like to congratulate everyone on the outcome. The satellite is placed in the precised orbit. Congratulates to the entire ISRO for making this mission happen,” ISRO Chairman Somnath said in a press conference.
He appreciated the fact that the mission was accomplished after doing the rectifications after suffering a debacle during the last mission.
“This mission GV-F12 came after the debacle that happened in the F-10 mission where there was an issue in the cryogenic stage and the cryogenic engine could not get accomplished. I am very happy that the correction and modification at the cryogenic stage were done and we learnt the lessons to make our cryogenic stage more reliable. I want to specifically congratulate the entire ‘Failure Analysis Committee’ who went through this and made our life much better and also for the Liquid Propulsion System,” he said.
Somnath added, “Today the Navigation Satellite NVS-01 is the second generation of navigation satellite with additional capabilities that we have already brought into the satellite constellation where we make the signals more secure. We made a civilian frequency band L-1 and also introduced our Atomic Clock. And this is one of the five series of satellites with new configurations that are to be launched. I would like to thank all those who worked for this satellite and make the mission a grand success”.
Appreciating the government support, the ISRO Chairman also thanked the authorisation of the GSLV launch despite a failure during the last attempt.
“The confidence of the decision makers, our honourable Prime Minister Narendra Modi and other key functionaries who reviewed it to see that we have done the required work. The Navic Constellation is something very crucial for the nation to have a regional navigation constellation. I take this opportunity to tell you that we are going to make this Navic system fully functional and operational for the benefit of this nation,” he said.
He further said that the satellite is currently in Geosynchronous Transfer Orbit, from where it is the responsibility of the satellite team to correctly place it in the orbit.
Apprising about the future missions of ISRO, Chairman Somnath said, “In the coming months, we are going to launch PSLV as well as GSLV Mark-3. We are also going to launch the test vehicle of the Gaganyan (Man mission). Of course, the launches of further PSLV and SSLV are also in line”
“We are having the next launch of GSLV with a Climate and weather observation satellite called INSAT-3DS, which will be happening soon. And after that, the same rocket is bound to take NISR – India Nasa Synthetic Alergic Radar Satellite as well,” he added.
China to Send First Civilian Into Space as Part of Crewed Mission: Details
China will send its first civilian astronaut into space as part of a crewed mission to the Tiangong space station on Tuesday, its Manned Space Agency announced, as Beijing pushes ahead with its extra-terrestrial ambitions.
The world’s second-largest economy has invested billions of dollars into its military-run space programme, trying to catch up with the United States and Russia after years of belatedly matching their milestones.
Until now, all Chinese astronauts sent into space have been part of the People’s Liberation Army.
“Payload expert Gui Haichao is a professor at Beijing University of Aeronautics and Astronautics,” China Manned Space Agency Spokesperson Lin Xiqiang told reporters Monday.
Gui will be “mainly responsible for the on-orbit operation of space science experimental payloads”, Lin said.
The commander is Jing Haipeng — on his fourth mission into space, according to state media — and the third crew member is engineer Zhu Yangzhu.
They are set to take off from the Jiuquan Satellite Launch Centre in northwest China on Tuesday at 9:31 am (0131 GMT), the Manned Space Agency said.
Gui’s university, known as Beihang University in English, said he hailed from an “ordinary family” in western Yunnan province.
He “first felt the attraction of aerospace” listening to the news of China’s first man in space, Yang Liwei, on campus radio in 2003, the university said in a post on social media.
Under President Xi Jinping, plans for China’s “space dream” have been put into overdrive.
China is planning to build a base on the Moon and the country’s National Space Administration said it aims to launch a crewed lunar mission by 2029.
The final module of the T-shaped Tiangong — whose name means “heavenly palace” — successfully docked with the core structure last year.
The station carries a number of pieces of cutting-edge science equipment, state news agency Xinhua reported, including “the world’s first space-based cold atomic clock system”.
Once finished, Tiangong is expected to remain in low Earth orbit at between 400 and 450 kilometres (250 and 280 miles) above the planet for at least 10 years — realising an ambition to maintain a long-term human presence in space.
It will be constantly crewed by rotating teams of three astronauts, who will conduct scientific experiments and help test new technologies.
While China does not plan to use Tiangong for global cooperation on the scale of the International Space Station, Beijing said it is open to foreign collaboration.
It is not yet clear how extensive that cooperation will be.
China has been effectively excluded from the International Space Station since 2011, when the United States banned NASA from engaging with the country.
Elon Musk’s Neuralink Now Has FDA Approval to Begin Human Trials
Elon Musk’s brain-implant company Neuralink on Thursday said the US Food and Drug Administration (FDA) had given the green light to its first-in-human clinical trial, a critical milestone after earlier struggles to gain approval.
The FDA nod “represents an important first step that will one day allow our technology to help many people,” Neuralink said in a tweet. It did not elaborate on the aims of the study, saying only that it was not recruiting yet and more details would be available soon.
Neuralink and the FDA did not immediately respond to Reuters requests for comment.
Musk envisions brain implants could cure a range of conditions including obesity, autism, depression, and schizophrenia as well as enabling web browsing and telepathy. He made headlines late last year when he said he was so confident in the devices’ safety that he would be willing to implant them in his children.
On at least four occasions since 2019, Musk predicted Neuralink would begin human trials. But the company only sought FDA approval in early 2022 and the agency rejected the application, seven current and former employees told Reuters in March.
The FDA had pointed out several concerns to Neuralink that needed to be addressed before sanctioning human trials, according to the employees. Major issues involved the lithium battery of the device, the possibility of the implant’s wires migrating within the brain, and the challenge of safely extracting the device without damaging brain tissue.
Neuralink, founded in 2016, has been the subject of several federal probes.
In May, US lawmakers urged regulators to investigate whether the makeup of a panel overseeing animal testing at Neuralink contributed to botched and rushed experiments.
The Department of Transportation is separately probing whether Neuralink illegally transported dangerous pathogens on chips removed from monkey brains without proper containment measures.
Neuralink is also under investigation by the US Department of Agriculture’s Office of Inspector General for potential animal-welfare violations. This probe has also been looking at the USDA’s oversight of Neuralink.
Neuralink has not responded to requests for comment on the probes.
© Thomson Reuters 2023
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