The Week in Space and Physics #17
The Week in Space and Physics #17
On space stations, the hunt for life on Mars, an odd neutron star and problems with the Dragon capsule
Quite when it will happen is hard to tell, but, like all endings, the demise of the International Space Station is inevitable. One day, perhaps a decade or more from now, something irreversible will happen: a splintering of the station walls, a failure of a critical component, perhaps.
Whatever the exact details, the station will sooner or later be abandoned. Controllers will order it to fall back to Earth, a command that will send it plunging through the atmosphere. For a few brief moments the hundred billion dollar wonder of engineering will burn; a dying star blazing a trail across the sky. Anything that survives will rest for centuries, buried in the depths of the Pacific Ocean.
At that point just one space station may be left in orbit: the Chinese Tiangong station. That, strategists fear, will deal a blow to American prestige. But it may also allow China to dominate the space around our planet, giving them the literal high ground in any future conflict. With no orbital outpost of their own, America would be at a severe strategic disadvantage.
China’s station, launched in April last year, is still relatively new. Comprised of just one module - Tianhe - the station is also small; there is room for just three astronauts on board. That, though, will soon change.
A fresh crew of astronauts arrived on Tiangong last week, beginning a six month campaign to expand the station. Two new modules will soon follow: Wentian, planned for July; and Mengtian, planned for October. With both attached and integrated the capacity of the station will be doubled: plans call for six astronauts to visit before the end of the year.
So far Tiangong has only hosted Chinese astronauts. But China sees the diplomatic opportunities that possessing such a station offer: they have repeatedly expressed interest in hosting foreign astronauts and experiments. Those are unlikely to come from America – NASA is forbidden from working with China – but could come from friendly nations like Russia, or even from Europe.
Indeed, once the International Space Station comes to an end, Tiangong may be the only option for space agencies to send experiments and humans into orbit. NASA is unwilling to pay for a new station in Earth orbit – the ISS, after all, had a price tag of more than one hundred billion dollars.
Instead they are funding commercial stations, hoping that private industry will be able to pick up the slack. Several companies – including Boeing and Blue Origin – have started planning stations of their own.
Strategists, then, might not need to regard the end of the space station with quite so much fear. It may instead be a chance to rethink the approach to space - and an opportunity to expand, not retrench, American activity in orbit.
The Hunt for Life on Mars
When the rover Perseverance landed on Mars, more than a year ago, it did so in an ancient crater. Long ago – billions of years in the past – a river flowed, at least sporadically, into this crater: thus turning it into a lake. That much seems clear. Perseverance, in its time on Mars, has uncovered plenty of evidence that water did indeed once flow across the surface of Mars.
Did life ever exist in that water? Theoretically, at least, Mars was once capable of supporting biology. The red planet may even have been more hospitable than Earth, forming a paradise in which alien thrived. Clues to this possible past may lie close to the edge of the crater, within the dried remains of an ancient river delta.
Researchers speculate that traces of long dead alien biology might be found there, buried in the sediments of the river. Perseverance has thus spent several weeks voyaging towards the delta. Now that it has arrived, mission operators are planning to spend the next few months exploring the region. Part of that will require the rover to collect samples of rock by drilling into the Martian surface.
Those samples – if scientists are excited enough by their contents – will be collected and left on the Martian surface. A decade from now, if all goes to plan, another probe will visit Mars, retrieve them and then loft them into orbit. They will then be collected by a waiting spacecraft, which will ferry them all the way back to Earth: making them the first ever rocks returned from the Red Planet.
That, of course, sounds fantastically complicated. But the effort could be worth it. Robotic probes on Mars are limited in what they can do, restricted to the range of instruments they carry with them. Researchers on Earth, by contrast, will be able to subject the Martian rocks to the full power of our laboratories. That – whether it reveals life or not – is a prize worth fighting for.
A Star That Lost Its Spin
If you scan the night skies for radio waves, as astronomers like to do, you’ll eventually notice that some stars seem to emit regular bursts of radio energy. These are neutron stars: rapidly spinning magnetic stars that produce beams of radio energy. Those beams sweep across the heavens, rather like a cosmic lighthouse.
Most spin extremely fast, creating a flash every few seconds. Theory has long suggested this rapid spin is key to producing the radio beams: without it, the star simply cannot generate enough energy. In a recent paper, however, a team of astronomers reported finding a neutron star that flashes less than once every minute.
Neutron stars are expected to slow down as they age, thus flashing less rapidly. But that should also weaken the signal – and one that rotates this slowly shouldn’t be visible at all. That implies something else is going on. The team behind it suggest the star could be extremely magnetic – a magnetar – and that this, somehow, drives the radio signal. Or, they say, perhaps something else is going on, and this star belongs to a new and hitherto unknown category.
Many more such stars could be out there. Astronomers, however, haven’t really been looking for them. Most searches focus on stars flashing on and off rapidly, and so those that flash more slowly – like this one – will, until now, have been missed.
Problems With The Dragon Capsule?
After discovering a possible fuel leak, SpaceX and NASA last week postponed a planned cargo flight to the International Space Station. The leak seems to have occurred in the thrusters of Dragon, SpaceX’s reusable capsule, though engineers are still tracing the root cause of the anomaly.
The incident follows another apparent issue with the Dragon capsule found in May. After the return of the AX-1 astronaut mission from the space station, engineers allegedly found issues with the capsule’s heat shield. This component is critical in protecting the spacecraft, and any astronauts onboard, from the extreme temperatures of re-entry.
The problems may stem from a fuel leak that ate away at the shield. NASA has since denied a leak took place – but SpaceX did decide to replace the heat shield on the next Crew Dragon flight. For now NASA seems happy with the safety of the capsule – and certainly it appears that the AX-1 astronauts were in no danger (at least more than normal) during re-entry.