The Week in Space and Physics: Mars Rocks
The Week in Space and Physics: Mars Rocks
On the Mars Sample Return, the James Webb's early galaxies, India's space ambitions and Artemis
In his first moments on the surface of the Moon, Neil Armstrong walked into the sunlight, took out a small teflon bag, and filled it with rocks and dirt from the surface. The crust was hard to break through, the watching Buzz Aldrin remarked, but Armstrong still managed to pick out four fragments of rock.
The astronauts carefully stowed the bag away on the Apollo landing module. For the mission controllers this was an important step: ensuring that whatever happened next, the astronauts would at least bring a small piece of the Moon back with them.
NASA needn’t have worried. Over the course of the Apollo program, astronauts collected more than two thousand other samples. Those pieces of rock and soil were analysed back on Earth in sophisticated laboratories; revealing the secrets of how the Moon formed and what it was made of. They remain, today, some of the most valuable rocks on Earth.
For decades, American and European scientists have been wondering how to do something similar for Mars. The obvious answer might be to send astronauts - yet despite the ambitions of engineers, politicians and entrepreneurs, such a mission is still decades away from reality. If we want Mars rocks anytime soon, we’ll need to find another way to get them.
Europe and America have thus settled on another approach. Over the next decade, if all goes to plan, NASA and ESA will send a series of elaborate robotic spacecraft to the Red Planet. Together those robots will collect samples, pick them up, fire them into space and bring them back to Earth.
This project, indeed, has already begun. The Perseverance rover, now in its third year on Mars, has drilled out and carefully stowed two dozen samples of Martian rock, soil and air. Under current plans, NASA will send another probe to Mars in 2028 to pick them up, possibly with the help of two robotic helicopters.
At the same time, ESA will send an orbiter to Mars. By the time it arrives, in 2030, NASA’s probe will have fired the samples into Martian orbit. The two spacecraft will meet and transfer the samples, which the ESA orbiter will then take back to Earth. If all goes to plan, scientists will get their hands on their first Mars rocks in 2033.
That, however, is a big if. The mission is fiendishly complex, requiring a whole load of things - from ascending from Mars, to an in-orbit rendezvous around another planet - that have never been tried before. It is also, according to recent reports, likely to be incredibly expensive.
A survey of planetary science in 2022 put the price tag at about five billion dollars. Should it get any more expensive, the report warned, other important missions would struggle to get funds. Yet a review of the project recently estimated costs closer to nine billion dollars. Launching by 2028, it also said, is unrealistic - a date in the 2030s, it went on, would be far more likely.
So acute are these problems that some wonder if the project will go ahead at all. Martian rock samples may be a prized goal, some planetary scientists have said, but it is not one that should put the rest of the field on hold. NASA, at least, will surely need to rethink the project, if only to bring costs and schedule under control. If they can’t, Martian geologists may end up waiting for the astronauts after all.
The James Webb’s Early Galaxies
After the James Webb Space Telescope launched, astronomers started racing to spot the earliest galaxies. Soon they were announcing strange discoveries - galaxies that were far bigger than expected, and older than seemed possible. So unexpected were the findings that some reports even suggested they put the Big Bang theory itself into question.
Those claims were always exaggerated. Yet the galaxies seen by the James Webb did indeed raise difficult questions about our models of cosmology. Chief among these is a model known as Lambda-CDM, which makes certain assumptions about dark matter, dark energy and ordinary matter. Computer simulations using Lambda-CDM can, when rerunning the history of the cosmos, end up with a universe that looks pretty much like the one we live in.
Unfortunately for cosmologists, it also predicts an early universe that looks very different to the one seen by the James Webb. That put the model in doubt - and hinted that researchers were missing something crucial about the evolution of the cosmos.
As astronomers have had more time to analyse the data coming from the James Webb, however, the story has started to change. Many of the oldest galaxies, indeed, have turned out not to be so old after all. One, for example, was thought to have formed less than three hundred million years after the Big Bang. Later studies showed it was far older - at least two billion years old - and so much less unexpected.
This suggests astronomers were rather hasty in their initial announcements. In the race to find the earliest galaxy, some researchers may have overlooked inconvenient data, or sounded more certain than the data allowed. Now, as they take a more careful look at those galaxies, they are finding the truth is rather less exciting.
In some cases, however, extra data has actually confirmed the extraordinary age of the galaxies. Enough of these galaxies remain, indeed, to leave our theories of cosmology in question. Cosmologists, despite the fading excitement, may still end up rethinking the history of the universe.
India Dreams of the Moon
India last week sketched out ambitions to build a space station and land astronauts on the Moon by 2040. The announcement, made by Prime Minister Narendra Modi, follows India’s successful landing of a probe and rover on the Moon in August.
Despite that success, however, India has not yet launched astronauts into space. The program to do so, Gaganyaan, has been underway for some years and seems to be proceeding more slowly than originally hoped. Yet last week India made an important step towards an eventual human launch, with a successful test of the capsule escape system.
A few more tests will be needed, including three uncrewed test flights of the capsule. If all goes well, India could fly astronauts by 2025. That would open the way to the space station and moon landing. Yet landing on the Moon is a big task - India will need to build a bigger rocket, for one thing, as well as the associated infrastructure to launch it.
Whether that can be done by 2040 is questionable. Still, the path sketched out by Modi resembles that taken by other space powers, including America and China. Both and now eyeing the Moon, and both hope, in the next decade or so, to send astronauts to its surface. India, indeed, has already signed onto America’s Artemis Accords, possibly opening the door to collaboration on future exploration of the Moon.
The Struggles of Artemis
NASA’s Moon program is in trouble. Almost a year after Artemis I, the first mission of the program, the project is still struggling with expensive rockets and a delayed lander. Things look so bad, indeed, that NASA has started hinting that a human landing will be delayed by up to three years - pushing it to 2028 rather than 2025.
NASA has said that each Artemis launch costs at least four billion dollars thanks, mostly, to the huge cost of the SLS rocket. That is unaffordable, a report last month concluded, and so puts the future of the Artemis program under threat. Since efforts to cut the costs of the rocket seem unconvincing, NASA may, in the end, be forced to seek an alternative rocket - of which the only viable option could be SpaceX’s Starship.
Yet delays with Starship are also creating problems. NASA is hoping to use that spacecraft as a Moon lander in 2025, yet it is unlikely to be ready in time. If it is not, NASA will probably have to change its plans for Artemis III - and therefore push a human landing out to Artemis IV, which will fly in 2028, at the earliest.