If we’re ever to make regular journeys from Earth to Mars and other far-off destinations, we might need new kinds of engines. Engineers are exploring revolutionary new technologies that could help us traverse the Solar System in much less time.
Because of the orbital paths Mars and Earth take around the Sun, the distance between them varies between 54.6 million km and 401 million km.
Missions to Mars are launched when the two planets make a close approach. During one of these approaches, it takes nine months to get to Mars using chemical rockets – the form of propulsion in widespread use.
That’s a long time for anyone to spend travelling. But engineers, including those at the US space agency (Nasa), are working with industrial partners to develop faster methods of getting us there.
So what are some of the most promising technologies?
Solar electric propulsion
Solar electric propulsion could be used to send cargo to Mars ahead of a human mission. That would ensure equipment and supplies were ready and waiting for astronauts when they arrived using chemical rockets, according to Dr Jeff Sheehy, chief engineer in Nasa’s Space Technology Mission Directorate.
With solar electric propulsion, large solar arrays unfurl to capture solar energy, which is then converted to electricity. This powers something called a Hall thruster.
There are pros and cons. On the upside, you need far less fuel, so the spacecraft becomes lighter. But it also takes your vehicle longer to get there.
“In order to carry the payload we’d need to, it would probably take between two to 2.5 years to get us there,” Dr Sheehy tells the BBC.
“For the kinds of outposts we’d need to build on Mars for crews to be able to survive for months, and the vehicles, you’d need a lot of cargo.”
Aerojet Rocketdyne is working on a Hall thruster for the Gateway, a proposed space station in lunar orbit.
“Solar is the best because we know we can scale it up,” Joe Cassidy, executive director of Aerojet Rocketdyne’s space division, explains.
“We’ve already got these flying today on communications satellites. The power level we fly at today is 10-15kW (kilowatts), and what we’re looking to do with the Gateway is to scale it up to something greater than 50kW.”
Mr Cassidy said Aerojet Rocketdyne’s Hall thruster will be much more fuel efficient than a liquid hydrogen and oxygen rocket engine.
But a good way to make access to space cheaper would be to have fewer launches, he explains.
“I think that solar electric propulsion is very good technology, using xenon as the propellant. But the two major drawbacks are the amount of time it takes to get there, and the size of the solar arrays,” says Tim Cichan, a human spaceflight architect at aerospace giant Lockheed Martin.
Dale Thomas, a professor and eminent scholar in systems engineering at the University of Alabama in Huntsville (UAH) concurs.
“Solar electric works well for smaller payloads, but we’re still having trouble getting it to scale,” he tells the BBC.
He thinks it could become an important alternative technology if the technical challenges can be solved. But for now, he says, there are other better options, such as nuclear thermal electric propulsion.
Nuclear thermal electric propulsion
Another idea is to use chemical rockets to lift off from Earth and to land on Mars. But for the middle part of the journey, some engineers propose using something called nuclear thermal electric propulsion.
Astronauts could be sent to the Gateway in Nasa’s Orion capsule. The Orion crew capsule would then dock with a transfer vehicle.
Once Orion has been connected to the transfer vehicle, a nuclear electric rocket would be used to get the crew capsule and the transport module to Mars, where they link up with a Mars orbiter and lander, which are waiting in Mars’ orbit.
In a nuclear thermal electric rocket, a small nuclear reactor heats up liquid hydrogen. The gaseous form of the element expands and shoots out of the thruster.
“If we can cut transit time [to Mars] down by 30-60 days, it will improve the exposure to radiation facing the crew,” says Mr Cassidy. “We’re looking at nuclear thermal as a key technology because it can enable faster transit times.”
Dale Thomas, together with UAH, has a study contract with Nasa to design a space rocket featuring a nuclear thermal engine. He thinks nuclear thermal electric is the closest new engine technology to being ready for use.
“Some of the trajectories we run in my lab, we can get the transit time down to three months, which is still a very long journey, but it’s about a third of the time that chemical propulsion requires to get us there,” he says.
Boeing is not so keen on nuclear thermal propulsion, because it worries about the effects a nuclear reactor might have on astronauts.
Mr Thomas disagrees: “This is a common misperception. The hydrogen propellant is a great radiation shield.
“The crew will be at one end of the vehicle, and the engine at the other end. As such, preliminary estimates show that the crew will get more radiation dosage from cosmic rays than from the nuclear thermal engine.”
However, he admits one downside of the technology is the inability to easily test it on Earth.
But Nasa is designing a ground test apparatus that scrubs the exhaust to remove radioactive particles – making ground tests possible.
Electric ion propulsion
Another idea is electric ion propulsion. These generate thrust by accelerating ions – charged atoms or molecules – using electricity.
Ion propulsion is already being used to power satellites in space. But they produce only a low thrust – more like the power of a hairdryer – and therefore have a low acceleration. But given time, they can reach high speeds.
Ad Astra says it is working on a type of thruster called the Vasimr that uses radio waves to ionise and heat a propellant and then a magnetic field to accelerate the resulting soup of particles – the plasma. The Vasimr is designed to produce much more thrust than a standard ion engine.
The electricity needed can be generated in different ways. But for sending humans to Mars, the team wants to use a nuclear reactor. The Vasimr would use solar electric for smaller payloads.
Ad Astra’s president and chief executive Franklin Chang Diaz, who is a former Nasa astronaut, says crewed missions need to get to Mars in less than nine months, ideally.
Going to the Red Planet is much harder than going to the Moon, he says.
“The solution is to go fast,” Mr Chang Diaz tells the BBC. “For a spacecraft that would weigh 400-600 metric tonnes, with a power level of 200 MW (megawatts), you can get to Mars in 39 days.”
Dale Thomas believes scaling up the Vasimr will be difficult, like going from the power of a lawnmower to a space rocket. But the technology does show promise.
“If, or perhaps I should say, when Ad Astra can solve the technical challenges of Vasimr, it does appear to be the best choice for electric propulsion at the human-ferrying spacecraft scale,” Mr Thomas says.
“The physics says that it should work. However, I must point out that Vasimr is still under development in the laboratory; it’s a long way from being flight-ready at any scale.”
Mr Chang Diaz doesn’t see a problem with scaling up, it’s just that there’s currently no market for a 10MW engine, so Ad Astra is sticking with 200kW.
“We have a market for the 200kW engine, there’s a lot of activity in low-Earth orbit and near the Moon to move cis-Earth satellites,” says Mr Chang Diaz.
Lockheed Martin also thinks the Vasimr is promising technology, but it is focusing on solar electric propulsion.
The case for chemical rockets
Although the new technologies are interesting, veteran space players Lockheed Martin and Boeing both think liquid chemical rockets need to be the bedrock of any human mission to Mars.
Lockheed Martin says we already have the technology we need to get to Mars, and chemical rockets are a proven technology that worked in all the Apollo missions.
“We already have the technology to get us to Mars today,” says Mr Cichan, the former system architect for Orion.
“There are some technical challenges, but it’s really about taking the technology we have, building the systems and gaining experience in flying in deep space that is the work ahead of us, as well as developing technology that will be groundbreaking in the future.”
Hydrogen upper stage launchers have been used since the 1960s, and they have a high success rate, he stresses.
“Nasa’s Space Launch System (SLS) has four liquid hydrogen and oxygen RS-25 rocket engines,” Rob Broeren, a Boeing rocket propulsion specialist tells the BBC.
“These are shuttle heritage engines, and the advantage of the RS-25’s is that they’re well proven, high-reliability engines.
“The nice thing about going with highly proven technologies is that you have full confidence that they definitely work. With new technologies, they sound good on paper, but when it comes to implementing them, you will run into issues that will delay you.”
When will we get to Mars?
A recent study by the Science and Technology Policy Institute (STPI) found that it was unlikely for human missions to Mars to follow Nasa’s timetable and begin in 2033.
Given the constraints on Nasa’s budgets, STPI thinks it is much more likely that we will leave for Mars in 2039, though the White House wants the US space agency to explore the Moon first by 2024, under its Artemis programme.
Dr Paul Dimotakis, John K Northrop professor of aeronautics and professor of applied physics at the California Institute of Technology (Caltech) is sceptical of the new technologies, and even chemical propulsion.
“I personally have not seen answers to technical questions of how to have enough chemical propulsion to last the long trip. It’s not known for a hydrogen-oxygen rocket to last longer than six months,” he says.
“We do not have a technical solution that addresses all the issues. Plus, someone has to demonstrate this before we send humans to Mars, and all of these things do not correspond to Nasa’s timetable.”
Top oil exporter Saudi Arabia targets net zero emissions by 2060
Saudi Arabia’s crown prince said on Saturday that the world’s top oil exporter aims to reach ‘net zero’ emissions of greenhouse gases – mostly produced by burning fossil fuels – by 2060 – 10 years later than the United States.
He also said it would double the emissions cuts it plans to achieve by 2030.
Crown Prince Mohammed bin Salman and his energy minister said Saudi Arabia would tackle climate change, but also stressed the continued importance of hydrocarbons and said it would continue to ensure oil market stability.
They were speaking at the Saudi Green Initiative (SGI) ahead of COP26, the U.N. climate conference in Glasgow at the end of the month, which hopes to agree deeper global emissions cuts to tackle global warming.
The United States, the world’s second biggest emitter, is committed to achieving ‘net zero’, meaning that it emits no more greenhouse gases than it can capture or absorb, by 2050. But China and India, the world’s biggest and third-biggest emitters, have not committed to this timeline.
Amin Nasser, chief executive of the state oil giant Saudi Aramco, said it was counterproductive to “demonise” hydrocarbons. He said Aramco aimed to expand its oil and gas production capacity while also achieving net zero emissions from its own operations by 2050.
He called for more global investment to ensure adequate crude oil supplies.
Prince Mohammed said in recorded remarks that the kingdom aimed to reach net zero by 2060 under its circular carbon economy programme, “while maintaining its leading role in strengthening security and stability of global oil markets”.
He said Saudi Arabia would join a global initiative on slashing emissions of methane by 30% from 2020 levels by 2030, which both the United States and the EU have been pressing.
‘HYDROCARBONS STILL NEEDED’
U.S. climate envoy John Kerry is due to attend a wider Middle East green summit in Riyadh on Monday.
The SGI aims to eliminate 278 million tonnes of carbon dioxide emissions per year by 2030, up from a previous target of 130 million tonnes. The crown prince said the SGI initiative would involve investments of over 700 billion riyals ($190 billion) in that time period.
Saudi Arabia’s economy remains heavily reliant on oil, although the crown prince is trying to promote diversification.
Energy minister Prince Abdulaziz bin Salman said the world needed fossil fuels as well as renewables.
“It has to be a comprehensive solution,” he said. “We need to be inclusive, and inclusivity requires being open to accept others’ efforts as long as they are going to reduce emissions.”
He said the kingdom’s younger generation “will not wait for us to change their future”.
He said net zero might be achieved before 2060 but the kingdom needed time to do things “properly”.
Another Gulf oil producer, the United Arab Emirates, this month announced a plan for net zero emissions by 2050.
The non-profit Climate Action Tracker consortium gives Saudi Arabia its lowest possible ranking, “Critically insufficient”.
Saudi Arabia’s first renewable energy plant opened in April and its first wind farm began generating in August.
It does, however, have plans to build a $5 billion plant to produce hydrogen, a clean fuel, and state-linked entities are pivoting to green fundraising. ($1 = 3.7507 riyals)
(Reporting by Yousef Saba and Saeed Azhar in Riyadh, Marwa Rashad in London and Maher Chmaytelli in Dubai; additional reporting by Raya Jalbi in Dubai; writing by Ghaida Ghantous; editing by Jason Neely and Kevin Liffey)
Former NASA Administrator Says Flooding Of Orbit With Satellites Could Block Humanity From Space – Space Bollyinside – BollyInside
‘The U.S. government and governments around the world are failing to properly manage collision risk.’ ‘If not remedied, the consequence will be losing access to space entirely, devastating not only satellite communications, but also human spaceflight, national security, weather prediction, disaster relief, climate science, and so much more.’
Former NASA administrator Jim Bridenstine calls on the US government to mandate better regulations for launching satellites into orbit Amazon’s Kuiper Systems is looking to send 3,326 communication satellites and OneWeb is proposing to build a constellation of 648 devices.
The company has sent more than 1,700 Starlink satellites in orbit, but it hopes to have as many as 42,000 devices circling Earth. More than 3,000 communication satellites are orbiting Earth, but dozens of companies are seeking approval from the Federal Communications Commissions (FCC) to launch thousands more. SpaceX, founded by Elon Musk, is building a megaconstellation to provide internet service to even the most remote parts of the world
SpaceX, founded by Elon Musk, is building a megaconstellation to provide its Starlink internet service to the most remote parts of the world. The development and use of satellite communications are advancing rapidly and transforming humanity.
However, these are just a few of the dozens of companies looking to achieve similar feats. Bridenstine said: ‘The US government and governments around the world are failing to properly manage collision risk.’ SpaceX has sent more than 1,700 Starlink satellites in orbit, but it hopes to have as many as 42,000 devices circling Earth
Bridenstine proposed solutions during the briefing, putting much of the responsibility on Congress and the FCC. ‘Dramatic increases in space collisions, and new space debris, are expected within just a few years,’ Bridenstine said during the briefing. ‘In the longer-term satellites are destroyed faster than they are launched.’
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- Headline: Former NASA Administrator Says Flooding Of Orbit With Satellites Could Block Humanity From Space
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Musk says Starship may be ready for orbital launch next month, but FAA review continues – Spaceflight Now – Spaceflight Now
Elon Musk, the billionaire founder of SpaceX, said Friday the company’s huge new Starship rocket could be ready for its first orbital test launch from South Texas as soon as November, but the schedule comes with two big uncertainties that may push the launch to next year.
“If all goes well, Starship will be ready for its first orbital launch attempt next month, pending regulatory approval,” Musk tweeted.
The new schedule update from Musk came the day after SpaceX test-fired the newest Starship vehicle, known as Ship 20 or SN20, at the company’s development facility near Boca Chica Beach east of Brownsville, Texas. A vacuum-rated Raptor engine, similar to the engines Starship will use in space, ignited for several seconds on a launching stand at SpaceX’s Starbase complex Thursday night.
SpaceX briefly fired the privately-developed rocket again later the same night.
It was the first test-firing of a Raptor vacuum engine mounted to a Starship rocket. The vacuum variant of the methane-fueled Raptor engine has a larger nozzle to improved performance in the airless environment of space.
Three vacuum-rated Raptor engines will fly on orbital-class Starship missions. Three sea level Raptor variants, with smaller nozzles, will be used for vertical Starship landings after returning from space.
Unlike the Starship prototypes flown on the recent atmospheric hops, Ship 20 is covered in thousands of heat-resistant tiles to protect the craft’s stainless steel structure from the scorching heat it will encounter during re-entry into Earth’s atmosphere.
First firing of a Raptor vacuum engine integrated onto a Starship pic.twitter.com/uCNAt8Kwzo
— SpaceX (@SpaceX) October 22, 2021
The Starship will launch on top of a huge reusable first stage booster called the Super Heavy. Made of stainless steel, the entire stack stands 394 feet (120 meters) tall, higher than any rocket ever built.
Fitted with up to 33 Raptor engines, the Super Heavy will propel the Starship into space with twice the thrust of NASA’s Apollo-era Saturn 5 moon rocket, and nearly double the power of NASA’s Space Launch System heavy-lift rocket.
In August, SpaceX teams in South Texas briefly stacked the entire Starship rocket on a launch mount for a fit check and photo opportunity. At the time, SpaceX connected 29 Raptor engines — four fewer than the booster will use on an operational flight — to the Super Heavy and rolled the booster to the ever-expanding launch complex, just east of the company’s build site.
After the fit check, SpaceX removed the Raptor engines from the Super Heavy, designated Booster 4, as attention turned to preparing Ship 20 for cryogenic proof testing in September.
SpaceX then readied Starship for its first static fire tests this week. More test-firings may occur before Ship 20 is mounted on top of the Super Heavy booster again.
Meanwhile, SpaceX plans to perform cryogenic proof testing of Booster 4 some time in the coming weeks, likely followed by a series of test-firings, culminating in a static fire with its full complement of Raptor engines.
Outfitting of the launch pad tower at Boca Chica has also continued since its initial construction over the summer. Earlier this week, crews lifted massive arms, nicknamed “chopsticks,” onto the launch tower that SpaceX aims to use for catching descending Super Heavy boosters.
Although SpaceX has moved forward with great speed at Boca Chica, the chances of the Super Heavy and Starship vehicles being ready for flight next month are uncertain. Musk often sets aspirational schedule goals, and in September 2019 said he wanted to attempt the first orbital launch attempt with Starship within six months.
Another schedule hurdle might be the Federal Aviation Administration, which is reviewing the environmental impacts of SpaceX’s operations in South Texas. The FAA issued a draft environmental report last month after consultation with several federal and state agencies.
The draft report marks a re-evaluation of the FAA’s original environmental impact statement before SpaceX started construction of the Boca Chica site in 2014. At that time, SpaceX planned to launch Falcon 9 and Falcon Heavy rockets from South Texas, but the scope of the project has since changed to focus on development of Starship and Super Heavy.
The FAA held public hearings Monday and Wednesday, and some 120 people voiced their opinions on the project’s environmental impacts. The public comments were more than two-to-one in favor of the FAA finalizing the draft programmatic environment assessment, and issuing SpaceX a launch license for the Starship orbital test flight.
Many of the comments in favor of SpaceX came from members of the public outside Texas. The share of people who identified themselves as local residents and voiced opposition was higher.
Joyce Hamilton, who said she was a member of the local community, worried that SpaceX would damage the “fragile and unique coastline” at Boca Chica Beach.
“In fact, we’ve already seen the damaging impact of a recent launch failure with a wide and destructive debris field along the beach and surrounding wetlands,” Hamilton said. “I’d like to just end by urging the FAA to conduct a serious comprehensive environmental impact study.”
Rebecca Hinojosa, a Brownsville resident, said SpaceX has been a destructive influence on the community through gentrification, and displaced residents who once lived near the Boca Chica site. SpaceX bought out homes in the area as it constructed the facility.
Others were supportive of the FAA allowing SpaceX to go ahead with no delay, citing the positive economic effects of SpaceX’s presence in the Rio Grande Valley.
“Elon Musk chose our community to be the next home of his SpaceX operation, and very, very quickly after setting up, this area went from being one of the poorest areas, one of the most looked-down, in the entire nation … We’re no longer in that position. We’re now one of the most sought after zip codes to live and raise your children,” said Jessica Tetreau, a Brownsville city commissioner.
“I don’t just ask you,” she concluded. “I beg you to give them that permit.”
“As far as the environment goes, it seems to me that SpaceX has a good plan in place to mitigate the vast majority of environmental effects from the build and test sites,” said Michael O’Halloran, who did not identify himself as a local resident. “Starship and Super Heavy are clearly worth the gamble.”
The FAA is accepting written comments until Nov. 1, then will determine whether to finalize the draft environmental assessment or begin a new environmental impact statement if the environmental effects would be significant and could not be properly mitigated.
A new environmental impact statement would take months, or even years, to complete.
A decision by the FAA on which route to take is not expected immediately. The FAA said it is reviewing the environmental impacts from SpaceX’s Starship launch and re-entry operations, debris recovery, the launch pad integration tower and other launch-related construction, and local road closures at Boca Chica.
SpaceX can’t launch the Starship and Super Heavy vehicle until the FAA issues a license, which will only come after the completion of the environmental process.
NASA awarded SpaceX a contract to develop a version of the Starship rocket as a human-rated lander for the agency’s Artemis moon missions.
That contract award is currently on hold after Blue Origin, the space company founded by billionaire Jeff Bezos, filed suit in the U.S. Court of Federal Claims. A ruling on the lawsuit could come next month.
SpaceX is developing the privately-owned Starship vehicle as a fully reusable launch and space transportation system capable of ferrying more than 100 metric tons of cargo into low Earth orbit, more than any other rocket in the world. SpaceX eventually aims to develop an in-space refueling capability to extend Starship’s heavy-duty cargo carrying range into the solar system.
During an orbital launch attempt, a reusable Super Heavy first stage booster will detach from the Starship and come back to Earth for a vertical landing. For the first orbital mission, SpaceX plans to guide the the booster to a water landing in the Gulf of Mexico.
SpaceX is also modifying offshore oil drilling rigs to serve as floating Starship launch and landing platforms.
The Starship will continue into orbit and deploy its payloads or travel to its deep space destination, and finally return to Earth to be flown again. The Starship vehicle doubles as an upper stage and a refillable transporter to ferry people and cargo through space to destinations in Earth orbit, the moon, Mars, and other distant locations.
The reusable architecture, which builds upon SpaceX’s partially reusable Falcon 9 rocket, is designed to reduce the cost of each flight.
The Starship’s first orbital test flight, though audacious in scale, will aim to prove out the rocket’s basic launch and re-entry capabilities without fully testing out the complicated landing and recovery systems, according to a SpaceX’s filing with the Federal Communications Commission earlier this year.
On the first orbital mission, SpaceX plans for the Starship to re-enter the atmosphere after one trip around Earth, heading for a controlled landing at sea in the Pacific Ocean near Hawaii.
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