Miniature spaceships the size of cellphones could fly across the solar system using sails propelled by lasers, which would allow the tiny spacecraft to reach much faster speeds — and, potentially, much more distant destinations — than conventionally powered rockets, a new study finds.
Current spacecraft usually take years to make trips within the solar system; for example, NASA’s New Horizons probe took nearly 10 years to reach Pluto.
In theory, spacecraft using conventional rockets would need thousands of years to complete an interstellar voyage. For example, Alpha Centauri, the nearest star system to Earth, lies about 4.37 light-years away — more than 25.6 trillion miles (41.2 trillion kilometers), or more than 276,000 times the distance from Earth to the sun. It would take NASA’s Voyager 1 spacecraft, which launched in 1977 and reached interstellar space in 2012, about 75,000 years to reach Alpha Centauri even if the probe were headed in the right direction, which it’s not.
The problem with all rocket thrusters is that the propellant they carry with them has mass. Long trips require a lot of propellant, which makes spacecraft heavy, which, in turn, requires more propellant, making them heavier, and so on.
Previous research has suggested that “light sailing” might be one of the only technically feasible ways to get a spacecraft to another star within a human lifetime. Although light does not exert much pressure, scientists have long suggested that what little pressure it does apply could have a major effect. Indeed, numerous experiments have shown that “solar sails” can rely on sunlight for propulsion if the spacecraft is light enough and has a large enough sail.
Indeed, the $100 million Breakthrough Starshot initiative, announced in 2016, plans to launch swarms of microchip-size spacecraft to Alpha Centauri, each of them sporting extraordinarily thin, incredibly reflective sails propelled by the most powerful lasers ever built. The plan has them flying at up to 20% the speed of light, reaching Alpha Centauri in about 20 years.
A major challenge Starshot faces is building the lasers needed for propulsion. It calls for a ground-based laser array on the order of 0.4 square miles (1 square kilometer) and as powerful as 100 gigawatts, which would be by far the most powerful laser ever made on Earth.
In the new study, the researchers suggest that a more humble ground-based laser array — one that’s 3.3 to 33 feet (1 to 10 meters) wide and 100 kilowatts to 10 megawatts in power — could still prove useful by sending tiny probes across the solar system, propelling them to much faster speeds than rocket engines could.
“Such lasers can be built already today with a relatively small investment,” study senior author Artur Davoyan, a materials scientist at the University of California, Los Angeles, told Space.com. “We do not need to wait till a 100-gigawatt laser becomes available.”
Going interstellar on a reasonable timescale imposes more constraints than voyaging within the solar system. For instance, Starshot aims to send probes to another star within a human lifetime, so its spacecraft are designed to be extraordinarily lightweight — each just 0.035 ounces (1 gram) or so — to fly as fast as possible given the amount of energy they receive.
Laser sails for interplanetary voyages, by contrast, do not have to be as lightweight. The scientists envision spacecraft for such trips ranging up to 3.5 ounces (100 g) or so — a mass “comparable with that of a typical cell phone,” Davoyan said.
Whereas Starshot faces mass constraints that make it challenging to fit all the needed spacecraft systems and instruments into a single platform, a 3.5-ounce probe “can easily be equipped with all the needed components, including spectrometers, accelerometers, particle detectors, cameras and so on — all the key ingredients to conduct a proper scientific mission in far reaches of space,” Davoyan said.
Furthermore, because a laser array can launch more than one probe, it could potentially send a fleet of tiny probes, each with different equipment, to a destination. “For example, one may be a magnetometer probe, another equipped with a camera, the third serving as a particle detector,” Davoyan said. “We foresee that many small probes can be sent to really different destinations to do breakthrough science.”
In addition, because interplanetary voyages do not require the kind of powerful lasers needed with Starshot, they also do not require large sails with the kind of extraordinary material properties needed to withstand the many demands of interstellar flight, such as not vaporizing under the light of such a powerful laser. The researchers suggested that silicon nitride or boron nitride sails about 4 inches (10 centimeters) wide should suffice for flights within the solar system.
“Our work is a first step to fast and low-cost interplanetary and deep space missions,” Davoyan said. “We see that a new model for space exploration can emerge, where individual users, which typically do not have access to space, could now spend just a few thousand dollars and launch a real deep space mission.”
Laser arrays on the order of 100 kilowatts are already under development by the U.S. military; in 2020, for instance, the U.S. Navy’s littoral combat ship USS Little Rock received a 150-kilowatt laser. Furthermore, the cost of high-power lasers is rapidly dropping every year, driven by the need for optical telecommunications, with 1-kilowatt lasers available for less than $10,000, Davoyan noted.
“Rough estimates show that [a] 1-megawatt laser beamer could be constructed with less than $100 million, which is far less than most of NASA’s missions,” Davoyan said. “Importantly, once built, the beamer can be used and reused to launch multiple probes in different directions. Essentially, the laser beamer is an initial capital investment and, once built, serves as a launchpad. The mission cost then consists of producing probes, which, with the use of mass manufacturing, can be on the order of $100, launching probes to orbit for less than $100 per probe and then operating a mission during its useful lifetime. Therefore, overall the laser-driven approach offers very low cost for space exploration.”
The scientists estimated that a 0.035-ounce laser sail with a 4-inch sail driven to speeds of about 112,000 mph (180,000 km/h) could reach Mars in 20 days, compared with the 200 days for NASA’s Perseverance rover; Jupiter in 120 days, compared with five years for NASA’s Juno probe; Pluto in less than three years, compared with 10 years for NASA’s New Horizons craft; and 100 times the distance of Earth from the sun in 10 years, compared with nearly 30 years for NASA’s Voyager 1 spacecraft.
“The fact that we can change the way space is being explored already today with a minimal investment is truly energizing,” Davoyan said. “Such an approach allows almost everyone to develop and launch their own mission — something that was not possible before. It would be really exciting to see an undergraduate student sending their own science probe to, say, Jupiter.”
The scientists now hope to test and prototype their ideas. “We are also partnering with industry and government to move further some of the designs and ideas we have,” Davoyan said. “We believe we can make a real difference in the future of space exploration.”
The scientists detailed their findings online Jan. 31 in the journal Nano Letters.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
