SPACE/COSMOS
Elon Musk greets Donald Trump as he arrives to attend a viewing of the launch of the sixth test flight of the SpaceX Starship rocket in Brownsville, Texas, U.S., November 19, 2024. Brandon Bell/Pool via REUTERS
December 02, 2024
Since Donald Trump’s recent electoral victory, rumours and speculation have circulated that Nasa’s giant Moon rocket, the Space Launch System (SLS), could be under threat. The rocket is one of several key elements needed for the US space agency’s Artemis programme, which aims to return humans to the Moon for the first time since 1972.
For the first lunar landing mission, called Artemis III, the SLS will launch four astronauts on Nasa’s Orion crew capsule. Orion will then travel to the Moon. Once in lunar orbit, Orion will dock with Elon Musk’s Starship vehicle (which has been launched separately). Two astronauts will float into Starship, which undocks from Orion and travels down to the lunar surface.
After walking on the Moon, the two astronauts return to lunar orbit in Starship, which docks with Orion. The two moonwalkers rejoin their crewmates and go home on Orion, leaving Starship in orbit around the Moon.
The US space journalist Eric Berger recently posted on X: “To be clear we are far from anything being settled, but based on what I’m hearing it seems at least 50-50 that Nasa’s Space Launch System rocket will be cancelled.”
No official announcements have been made. However, such a move could be in line with previous speculation that the Trump administration could gut Nasa, forcing it to contract out much of its work to the private companies.
But could another rocket easily take the place of the SLS? This question goes to the heart of what America wants to achieve amid an emerging 21st-century space race. China has pledged to send its astronauts to the lunar surface by 2030. Unlike the US, China is usually conservative in its estimates, so we can assume deadline slippage is unlikely. Meanwhile, several elements of Artemis are holding up the schedule.
One of these delayed elements is Musk’s Starship, which acts as the lander on Artemis III. It still needs to demonstrate key milestones including refuelling in space and performing a landing on the Moon without crew. Some in the space community believe that if China were to get to the Moon first this century, it would deal a significant blow to US ambitions in space.
Musk has been brought into the incoming administration as one of two chief cost cutters, aiming to make reductions of up to US$2 trillion (£1.57 trillion) from the federal budget. Some observers have been alarmed by Elon Musk’s closeness to Trump and by comments by the president-elect about shifting focus towards a crewed Mars mission.
These comments seem to mirror the views of Musk, who has focused much of his energy on ambitions to settle the red planet, not the Moon. The billionaire has said he wants to send humans on a trip to Mars using his Starship vehicle by 2028 – a timeline that some view as unrealistic.
The SLS performed very well during the Artemis I mission in 2022. NASA/Kim Shiflett
It was actually the first Trump administration that established the Artemis programme in 2017. After initial missions to the lunar surface, the programme aims to establish a permanent base where astronauts can learn how to live and work on the Moon, carrying out cutting-edge research.
However, the schedule has been slipping. US astronauts were to have landed on the Moon this year. Nasa now says the first landing, during the Artemis III mission, will not take place until Autumn 2026.
Delays have been introduced by redesigns to spacesuits, problems with Orion’s heat-shield and life support systems and, as mentioned, with Starship. An upgraded mobile launch tower for the SLS has also been plagued by cost overruns and schedule slippage.
Since Donald Trump’s recent electoral victory, rumours and speculation have circulated that Nasa’s giant Moon rocket, the Space Launch System (SLS), could be under threat. The rocket is one of several key elements needed for the US space agency’s Artemis programme, which aims to return humans to the Moon for the first time since 1972.
For the first lunar landing mission, called Artemis III, the SLS will launch four astronauts on Nasa’s Orion crew capsule. Orion will then travel to the Moon. Once in lunar orbit, Orion will dock with Elon Musk’s Starship vehicle (which has been launched separately). Two astronauts will float into Starship, which undocks from Orion and travels down to the lunar surface.
After walking on the Moon, the two astronauts return to lunar orbit in Starship, which docks with Orion. The two moonwalkers rejoin their crewmates and go home on Orion, leaving Starship in orbit around the Moon.
The US space journalist Eric Berger recently posted on X: “To be clear we are far from anything being settled, but based on what I’m hearing it seems at least 50-50 that Nasa’s Space Launch System rocket will be cancelled.”
No official announcements have been made. However, such a move could be in line with previous speculation that the Trump administration could gut Nasa, forcing it to contract out much of its work to the private companies.
But could another rocket easily take the place of the SLS? This question goes to the heart of what America wants to achieve amid an emerging 21st-century space race. China has pledged to send its astronauts to the lunar surface by 2030. Unlike the US, China is usually conservative in its estimates, so we can assume deadline slippage is unlikely. Meanwhile, several elements of Artemis are holding up the schedule.
One of these delayed elements is Musk’s Starship, which acts as the lander on Artemis III. It still needs to demonstrate key milestones including refuelling in space and performing a landing on the Moon without crew. Some in the space community believe that if China were to get to the Moon first this century, it would deal a significant blow to US ambitions in space.
Musk has been brought into the incoming administration as one of two chief cost cutters, aiming to make reductions of up to US$2 trillion (£1.57 trillion) from the federal budget. Some observers have been alarmed by Elon Musk’s closeness to Trump and by comments by the president-elect about shifting focus towards a crewed Mars mission.
These comments seem to mirror the views of Musk, who has focused much of his energy on ambitions to settle the red planet, not the Moon. The billionaire has said he wants to send humans on a trip to Mars using his Starship vehicle by 2028 – a timeline that some view as unrealistic.
The SLS performed very well during the Artemis I mission in 2022. NASA/Kim ShiflettIt was actually the first Trump administration that established the Artemis programme in 2017. After initial missions to the lunar surface, the programme aims to establish a permanent base where astronauts can learn how to live and work on the Moon, carrying out cutting-edge research.
However, the schedule has been slipping. US astronauts were to have landed on the Moon this year. Nasa now says the first landing, during the Artemis III mission, will not take place until Autumn 2026.
Delays have been introduced by redesigns to spacesuits, problems with Orion’s heat-shield and life support systems and, as mentioned, with Starship. An upgraded mobile launch tower for the SLS has also been plagued by cost overruns and schedule slippage.
Could Nasa’s Orion crew capsule launch on another rocket? Nasa
Notably, an element that isn’t contributing to delays is the SLS, which performed very well during the Artemis I mission in 2022. Many billions of dollars have already been invested in designing and building the SLS and associated infrastructure at Nasa’s Kennedy Space Center in Florida.
Nasa says the SLS is “the only rocket that can send Orion, astronauts, and cargo directly to the Moon in a single launch”. But its expense has been criticised: each SLS launch is estimated to cost more than US$2 billion (£1.6 billion).
News of delays and technical issues with Artemis have coincided with hugely positive PR for Musk’s SpaceX – especially around its test flights of Starship. This included last month’s feat, where the vehicle’s massive booster stage was caught in a pair of robotic arms as it fell back from space to the company’s launchpad in Texas – wowing space enthusiasts around the world. Unlike many launch vehicles, Starship is designed to be fully reusable. Its cost efficiency could greatly benefit future crewed missions.
If the SLS were to be cancelled, could Musk’s Starship replace it? Under this scenario, the SpaceX vehicle could presumably serve both as the launcher to send astronauts on their way to lunar orbit and as the lander to take them down to the surface. This is technically feasible, but would be far from a straightforward, like-for-like replacement. The SLS is already an operational rocket, whereas Starship is still in its testing phase and has key steps still to achieve before astronauts can board it.
Another SpaceX rocket that has previously been touted as a contender to launch Orion is the Falcon Heavy. However, engineers would need to modify both the rocket and procedures for assembly and launch. This would carry many uncertainties, and with it the risk of further, significant delays to the Artemis schedule. This all suggests that there is not a lot of time to make major changes to Nasa’s Moon programme if the US is to get ahead in this 21st-century space race.
Notably, an element that isn’t contributing to delays is the SLS, which performed very well during the Artemis I mission in 2022. Many billions of dollars have already been invested in designing and building the SLS and associated infrastructure at Nasa’s Kennedy Space Center in Florida.
Nasa says the SLS is “the only rocket that can send Orion, astronauts, and cargo directly to the Moon in a single launch”. But its expense has been criticised: each SLS launch is estimated to cost more than US$2 billion (£1.6 billion).
News of delays and technical issues with Artemis have coincided with hugely positive PR for Musk’s SpaceX – especially around its test flights of Starship. This included last month’s feat, where the vehicle’s massive booster stage was caught in a pair of robotic arms as it fell back from space to the company’s launchpad in Texas – wowing space enthusiasts around the world. Unlike many launch vehicles, Starship is designed to be fully reusable. Its cost efficiency could greatly benefit future crewed missions.
If the SLS were to be cancelled, could Musk’s Starship replace it? Under this scenario, the SpaceX vehicle could presumably serve both as the launcher to send astronauts on their way to lunar orbit and as the lander to take them down to the surface. This is technically feasible, but would be far from a straightforward, like-for-like replacement. The SLS is already an operational rocket, whereas Starship is still in its testing phase and has key steps still to achieve before astronauts can board it.
Another SpaceX rocket that has previously been touted as a contender to launch Orion is the Falcon Heavy. However, engineers would need to modify both the rocket and procedures for assembly and launch. This would carry many uncertainties, and with it the risk of further, significant delays to the Artemis schedule. This all suggests that there is not a lot of time to make major changes to Nasa’s Moon programme if the US is to get ahead in this 21st-century space race.
Nasa has previously looked at whether Orion could be launched on a Falcon Heavy rocket. SpaceX, CC BY-NC
Rocket launches require specific designs to meet mission requirements, as well as extensive planning for carrying astronauts, spacecraft and payloads. The aims of Artemis are not just to land astronauts on the Moon, but to be able to land in a variety of regions on the lunar surface, including the relatively unexplored south pole.
The planning and development required is hugely complex and ambitious. It remains to be seen whether SpaceX, or any other commercial launch companies, are ready for such a major undertaking and commitment.
With tens of billions of dollars already invested in the SLS, it does not seem economically beneficial to completely scrap the rocket. As indicated by Nasa’s willingness to seek an innovative approach and work with commercial companies on future Artemis missions, there could be other ways for commercial space players to get involved.
It’s understandable for the incoming Trump administration to raise questions and query cost models in Nasa programmes. But it would be advisable for them to carefully consider the trade offs before making decisions with such wide-ranging consequences.
It might fall down to whether the priority is winning the new space race. Whatever goals that the new administration chooses to prioritise or target, it may have to carefully justify that decision to other legislators and to the American public.
Yang Gao, Professor of Robotics, Head of Centre for Robotics Research, King's College London
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Rocket launches require specific designs to meet mission requirements, as well as extensive planning for carrying astronauts, spacecraft and payloads. The aims of Artemis are not just to land astronauts on the Moon, but to be able to land in a variety of regions on the lunar surface, including the relatively unexplored south pole.
The planning and development required is hugely complex and ambitious. It remains to be seen whether SpaceX, or any other commercial launch companies, are ready for such a major undertaking and commitment.
With tens of billions of dollars already invested in the SLS, it does not seem economically beneficial to completely scrap the rocket. As indicated by Nasa’s willingness to seek an innovative approach and work with commercial companies on future Artemis missions, there could be other ways for commercial space players to get involved.
It’s understandable for the incoming Trump administration to raise questions and query cost models in Nasa programmes. But it would be advisable for them to carefully consider the trade offs before making decisions with such wide-ranging consequences.
It might fall down to whether the priority is winning the new space race. Whatever goals that the new administration chooses to prioritise or target, it may have to carefully justify that decision to other legislators and to the American public.
Yang Gao, Professor of Robotics, Head of Centre for Robotics Research, King's College London
This article is republished from The Conversation under a Creative Commons license. Read the original article.
The Conversation
December 2, 2024
Radio signal in Space (Shutterstock)
Slowly repeating bursts of intense radio waves from space have puzzled astronomers since they were discovered in 2022.
In new research, we have for the first time tracked one of these pulsating signals back to its source: a common kind of lightweight star called a red dwarf, likely in a binary orbit with a white dwarf, the core of another star that exploded long ago.
A slowly pulsing mystery
In 2022, our team made an amazing discovery: periodic radio pulsations that repeated every 18 minutes, emanating from space. The pulses outshone everything nearby, flashed brilliantly for three months, then disappeared.
We know some repeating radio signals come from a kind of neutron star called a radio pulsar, which spins rapidly (typically once a second or faster), beaming out radio waves like a lighthouse. The trouble is, our current theories say a pulsar spinning only once every 18 minutes should not produce radio waves.
So we thought our 2022 discovery could point to new and exciting physics – or help explain exactly how pulsars emit radiation, which despite 50 years of research is still not understood very well.
More slowly blinking radio sources have been discovered since then. There are now about ten known “long-period radio transients”.
However, just finding more hasn’t been enough to solve the mystery.
Searching the outskirts of the galaxy
Until now, every one of these sources has been found deep in the heart of the Milky Way.
This makes it very hard to figure out what kind of star or object produces the radio waves, because there are thousands of stars in a small area. Any one of them could be responsible for the signal, or none of them.
So, we started a campaign to scan the skies with the Murchison Widefield Array radio telescope in Western Australia, which can observe 1,000 square degrees of the sky every minute. An undergraduate student at Curtin University, Csanád Horváth, processed data covering half of the sky, looking for these elusive signals in more sparsely populated regions of the Milky Way.
One element of the Murchison Widefield Array, a radio telescope in Western Australia that observes the sky at low radio frequencies. ICRAR / Curtin University
And sure enough, we found a new source! Dubbed GLEAM-X J0704-37, it produces minute-long pulses of radio waves, just like other long-period radio transients. However, these pulses repeat only once every 2.9 hours, making it the slowest long-period radio transient found so far.
Where are the radio waves coming from?
We performed follow-up observations with the MeerKAT telescope in South Africa, the most sensitive radio telescope in the southern hemisphere. These pinpointed the location of the radio waves precisely: they were coming from a red dwarf star. These stars are incredibly common, making up 70% of the stars in the Milky Way, but they are so faint that not a single one is visible to the naked eye.
The source of the radio waves, as seen by the MWA at low resolution (magenta circle) and MeerKAT at high resolution (cyan circle). The white circles are all stars in our own Galaxy. Hurley-Walker et al. 2024 / Astrophysical Journal Letters
Combining historical observations from the Murchison Widefield Array and new MeerKAT monitoring data, we found that the pulses arrive a little earlier and a little later in a repeating pattern. This probably indicates that the radio emitter isn’t the red dwarf itself, but rather an unseen object in a binary orbit with it.
Based on previous studies of the evolution of stars, we think this invisible radio emitter is most likely to be a white dwarf, which is the final endpoint of small to medium-sized stars like our own Sun. If it were a neutron star or a black hole, the explosion that created it would have been so large it should have disrupted the orbit.
It takes two to tango
So how do a red dwarf and a white dwarf generate a radio signal?
The red dwarf probably produces a stellar wind of charged particles, just like our Sun does. When the wind hits the white dwarf’s magnetic field, it would be accelerated, producing radio waves.
This could be similar to how the Sun’s stellar wind interacts with Earth’s magnetic field to produce beautiful aurora, and also low-frequency radio waves.
Until now, every one of these sources has been found deep in the heart of the Milky Way.
This makes it very hard to figure out what kind of star or object produces the radio waves, because there are thousands of stars in a small area. Any one of them could be responsible for the signal, or none of them.
So, we started a campaign to scan the skies with the Murchison Widefield Array radio telescope in Western Australia, which can observe 1,000 square degrees of the sky every minute. An undergraduate student at Curtin University, Csanád Horváth, processed data covering half of the sky, looking for these elusive signals in more sparsely populated regions of the Milky Way.
One element of the Murchison Widefield Array, a radio telescope in Western Australia that observes the sky at low radio frequencies. ICRAR / Curtin University
And sure enough, we found a new source! Dubbed GLEAM-X J0704-37, it produces minute-long pulses of radio waves, just like other long-period radio transients. However, these pulses repeat only once every 2.9 hours, making it the slowest long-period radio transient found so far.
Where are the radio waves coming from?
We performed follow-up observations with the MeerKAT telescope in South Africa, the most sensitive radio telescope in the southern hemisphere. These pinpointed the location of the radio waves precisely: they were coming from a red dwarf star. These stars are incredibly common, making up 70% of the stars in the Milky Way, but they are so faint that not a single one is visible to the naked eye.
The source of the radio waves, as seen by the MWA at low resolution (magenta circle) and MeerKAT at high resolution (cyan circle). The white circles are all stars in our own Galaxy. Hurley-Walker et al. 2024 / Astrophysical Journal Letters
Combining historical observations from the Murchison Widefield Array and new MeerKAT monitoring data, we found that the pulses arrive a little earlier and a little later in a repeating pattern. This probably indicates that the radio emitter isn’t the red dwarf itself, but rather an unseen object in a binary orbit with it.
Based on previous studies of the evolution of stars, we think this invisible radio emitter is most likely to be a white dwarf, which is the final endpoint of small to medium-sized stars like our own Sun. If it were a neutron star or a black hole, the explosion that created it would have been so large it should have disrupted the orbit.
It takes two to tango
So how do a red dwarf and a white dwarf generate a radio signal?
The red dwarf probably produces a stellar wind of charged particles, just like our Sun does. When the wind hits the white dwarf’s magnetic field, it would be accelerated, producing radio waves.
This could be similar to how the Sun’s stellar wind interacts with Earth’s magnetic field to produce beautiful aurora, and also low-frequency radio waves.
An artist’s impression of the AR Sco system: a binary red dwarf and white dwarf that interact to produce radio emission.
We already know of a few systems like this, such as AR Scorpii, where variations in the brightness of the red dwarf imply that the companion white dwarf is hitting it with a powerful beam of radio waves every two minutes. None of these systems are as bright or as slow as the long-period radio transients, but maybe as we find more examples, we will work out a unifying physical model that explains all of them.
On the other hand, there may be many different kinds of system that can produce long-period radio pulsations.
Either way, we’ve learned the power of expecting the unexpected – and we’ll keep scanning the skies to solve this cosmic mystery.
Natasha Hurley-Walker, Radio Astronomer, Curtin University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
We already know of a few systems like this, such as AR Scorpii, where variations in the brightness of the red dwarf imply that the companion white dwarf is hitting it with a powerful beam of radio waves every two minutes. None of these systems are as bright or as slow as the long-period radio transients, but maybe as we find more examples, we will work out a unifying physical model that explains all of them.
On the other hand, there may be many different kinds of system that can produce long-period radio pulsations.
Either way, we’ve learned the power of expecting the unexpected – and we’ll keep scanning the skies to solve this cosmic mystery.
Natasha Hurley-Walker, Radio Astronomer, Curtin University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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