The Week in Space and Physics
Winter comes to Mars, Starliner reaches the Space Station, NASA puts spacewalks on hold and a cold summer on Neptune.
Perseverance, Ingenuity, Curiosity and Insight. NASA’s list of rovers on Mars sometimes seems to have been drawn from a job applicant’s overly boastful resume. Soon, however, that list is likely to become a lot shorter: as the Martian winter closes in, some of NASA’s rovers are about to die.
The two most in trouble are Ingenuity and Insight. Both are operating far beyond their planned lifespans and both are now suffering from falling power levels. That’s partly thanks to darker and colder winter days, but also down to storms that see clouds of dust sweep across the planet. As each passes by, the rovers’ solar panels gather layers of dust, further reducing the energy they can gather.
After more than twelve hundred Earth days on the Martian surface, the damage this dust has wrought on Insight is plain to see. Images of the lander, taken with the last of its fading power, show a stark contrast between the fresh panels seen shortly after landing, and the dust covered ones seen more recently.
Unlike many of the other rovers on Mars, Insight is stationary. It was designed to study the interior of the planet: to listen for Marsquakes and, from the fine detail of how they move the surface, deduce what lies far below the surface. In that the probe has been a success. Over the last four years Insight detected more than a thousand Marsquakes, data from which has revealed new details of the planet’s molten core.
The landing site, close to the planet’s equator, turned out to be far less windy than mission planners had expected. That allowed dust to build up quickly – and operators have no easy way to clean it off. Over the years the power generated by Insight has fallen from five kilowatt hours a day at landing to just half a kilowatt hour today. That, NASA says, is too little to keep the probe going. Insight is likely to turn off forever within a few months.
Ingenuity, by contrast, arrived on Mars just over a year ago. It, a small helicopter, was only designed to last a few weeks on the surface. It has far surpassed that: lasting longer and flying further than anyone thought. Yet Ingenuity cannot outfly the dust, nor the cold winter days. It too is suffering from falling power levels and facing the end of its mission.
Earlier this month the helicopter failed to contact mission control as expected. Engineers believe its batteries ran low during the Martian night and, as a result, it temporarily turned off. That is a problem, as Ingenuity can only be controlled through Perseverance, a nearby rover. Once it powered off, it lost the connection with the rover.
To regain contact, engineers commanded Perseverance to spend an entire day listening for signals from Ingenuity. Fortunately that was enough to re-establish contact, and engineers have since made changes to preserve what power remains. That might be enough to survive a few weeks longer – but Martian winters are bitterly cold, and Ingenuity is unlikely to have enough power to reach the spring.
Starliner Reaches the Space Station
At the end of 2019, Boeing attempted to send Starliner, a capsule designed to one day carry astronauts, to the International Space Station. Though NASA and Boeing both tried to put a positive spin on things, the mission was, simply put, a disaster.
An error in the capsule’s clock caused an automated burn to fire early, wasting fuel and sending the capsule hurtling into the wrong orbit. That was bad enough, leaving the capsule unable to reach the space station. But then another software error was found which, had it not been discovered, would have sent the capsule plunging back into the atmosphere.
Fortunately engineers were able to fix the software bug, and Starliner did at least safely land after the flight. Still, the performance did nothing to inspire confidence that the capsule was capable of carrying astronauts safely. NASA thus forced Boeing to prepare for another attempt.
That attempt has been a long time coming, but, after two and a half years of work, Starliner finally launched again last week. Things seem to be progressing more smoothly this time: after a flight of around twenty-four hours the capsule arrived at and docked with the Space Station. Astronauts on board the station were then able to open up the capsule and visit its interior.
Not everything has gone to plan: issues seem to have come up with two of Starliner’s thrusters, though reports indicate that this is not a major issue. Another problem still remains with valves in the capsule’s propulsion system, though a temporary solution has been found for this. Overall, however, the test seems to be reasonably successful, at least so far.
That would be good news. NASA has been relying on SpaceX to ferry astronauts to the Space Station. Should anything go wrong with their Dragon capsule, however, NASA would be left in a tough spot. The only other alternative is the Russian Soyuz vehicle – a highly reliable spacecraft, but one caught up in a tricky geopolitical situation.
If Starliner is proven to work, NASA will soon have two independent methods of carrying astronauts into orbit. That ability could be proven later this year: the next step for Starliner will be a crewed flight to the Space Station.
Spacewalks on Hold
How do you drown in space? In 2013, Italian astronaut Luca Parmitano came perilously close to finding out. During a spacewalk around the International Space Station a leak inside his suit started to fill the helmet with water. Before long the liquid – pooling at the top of his helmet – blinded him and knocked out his radio communications, separating him from the other astronauts on the walk.
Fortunately, and thanks to some quick thinking, Luca was able to make it back inside the station before the helmet – and his lungs – filled with water. The incident led NASA to suspend spacewalks for some time, until the cause could be found and fixed. Earlier this year, however, a second astronaut – Matthias Maurer – again experienced a leak in his suit.
This time the incident seems to have been less serious. Reports say the water was only discovered at the end of the walk, as Maurer took off the suit inside the station. Still, NASA is taking it seriously. Spacewalks have once again been suspended while the cause of the leak is investigated.
The issues highlight the need for more modern spacesuits. NASAs current suits are decades old. Plans to build a replacement – aimed at lunar missions – have run years behind schedule and millions over budget. They also show the inherent dangers of spacewalks. With SpaceX hoping to organise a spacewalk of their own sometime soon, that risk is vital to keep in mind.
A Cold Summer on Neptune
Summer on Neptune, of course, is always cold. The planet lies on the frozen fringe of the Solar System, a place where temperatures are always hundreds of degrees below freezing. Yet the current summer season on the planet seems to be even colder than expected.
Neptune’s seasons, thanks to its centuries long orbit, last around four decades each. At the moment the planet’s southern hemisphere is entering early summer, a period that should see the region start to warm. Yet observations show the opposite – the planet seems to have been cooling for the last two decades. Only the south pole itself seems to have warmed – and that just in the last two years.
The reason for these strange temperature trends is unclear. Little is known about the distant planet, and our models of its atmosphere are still fairly simple. It seems likely complex phenomena are driving these temperature swings, but more detailed observations will surely be needed to understand what those are.
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