Space News & Blog Articles

Mars is a lifeless wasteland for more than one reason.  Not only are the temperatures and lack of water difficult for life to deal with, the lack of a magnetic field means radiation constantly pummels the surface.  If humans ever plan to spend prolonged periods of time on the red planet, they’ll need to support an additional type of life – crops.  However, it appears that even greenhouses on the surface won’t do enough to protect their plants from the deadly radiation of the Martian surface, at least according to a new paper published by researchers at Wageningen University and the Delft University of Technology.

Ideally, agriculture on the Maritan surface would consist of greenhouse domes and allow what limited sunlight hits the planet to make it through to the crops they house directly.  However, current technology greenhouse glass is incapable of blocking the deadly gamma radiation that constantly irradiates Mars.  Those gamma radiation levels, which are about 17 times higher on Mars than on Earth, are enough to affect crops grown in greenhouses on the surface significantly.

The researchers ran an experiment where they planted garden cress and rye and measured the crop output of a group irradiated with Martian levels of gamma radiation with those grown in a “normal” environment with only Earth-level radiation.  The crops in the irradiated group ended up as dwarves, with brown leaves, and resulted in a significantly decreased harvest after 28 days of growth.

To mimic the gamma radiation environment, Nyncke Tack, an undergraduate researcher who performed much of the work for the project, used 5 separate cobalt-60 radiation sources.  These were scattered evenly overhead of the test crops to create a “radiation plane” similar to the ever-present radiation field on Mars.  

Other confounding factors, including adding beta and alpha radiation, could also contribute to crop deterioration, though solid objects more easily stop those types of radiation.  The research team, who was not surprised by their findings, suggests building underground farms where the planet’s regolith blocks most if not all of that radiation.  This would have the obvious disadvantage of losing access to sunlight, but would have the added benefit of being a much more controllable environment, with LEDs and temperature control filling in for environmental conditions on the surface.

The fight over who gets to take the Artemis astronauts back to the Moon continues! It all began when NASA announced that they had awarded the contract for its Human Landing System (HLS), the reusable lunar lander that would ferry the Artemis III astronauts to the lunar surface. This decision did not sit well with the other two finalists, Blue Origin and Dynetics, who appealed the decision because NASA was showing “favoritism.”

The Government Accountability Office (GAO) rejected these appeals, which has prompted Blue Origin founder Jeff Bezos to bring out the big guns. In addition to filing a lawsuit in federal court and lobbying Congress, they have also waged a public relations war against SpaceX itself, calling their safety record and into question. In response, Elon Musk took to Twitter to address Blue Origin’s claims and set the record straight.

Blue Origin filed the lawsuit on August 13th in the US Court of Federal Claims, which addresses monetary claims made against the U.S. government and has jurisdiction wherever protests are made in response to GAO reviews. In a statement that accompanied the filing, a Blue Origin spokesperson repeated previous claims about NASA’s procurement process:

“Blue Origin filed suit in the U.S. Court of Federal Claims in an attempt to remedy the flaws in the acquisition process found in NASA’s Human Landing System. We firmly believe that the issues identified in this procurement and its outcomes must be addressed to restore fairness, create competition, and ensure a safe return to the Moon for America.” 

Musk weighed in on the controversy online in response to a Twitter post made by Christian Davenport, a space reporter with The Washington Post. Reporting on the ongoing controversy, Davenport posted an excerpt from Blue Origin’s legal filing. The excerpt refers to the report made by the GAO in response to protests issued by Blue Origin and Dynetics back in April (shortly after NASA announced its decision to go with a single contractor).

Black holes don’t emit light, which makes them difficult to study. Fortunately, many black holes are loud eaters. As they consume nearby matter, surrounding material is superheated. As a result, the material can glow intensely, or be thrown away from the black hole as relativistic jets. By studying the light from this material we can study black holes. And as a recent study shows, we can even determine their size.

Active supermassive black holes, also known as active galactic nuclei (AGN). Don’t simply shine with constant brightness. Their luminosity can change slightly over time. The timescale of this flickering can be anywhere from hours to years. Early studies have argued that this could be related to the size of the black hole, but the relationship isn’t always clear.

The basic idea is that the flickering is caused by an accretion disk around a black hole. The disk can be light-hours or light-days across. Since the speed of light is the maximum cosmic speed limit, that means overall changes in the disk will take at least hours or days. This works pretty well to tell you the maximum size of a black hole. For example, the rapid flickering of quasars tells us that they must be powered by black holes rather than some galaxy-spanning effect. But this doesn’t mean that AGNs flickering on a decade timescale are ten light-years across. Light speed is only an upper limit, and most effects propagate much more slowly.

In this new study, the team looked not at a simple flicker rate, but at the distribution of flicker rates known as the power spectrum density (PSD). They found that the scale at which the PSD levels off correlates to the size of the black hole. A particular black hole may have faster or slower flicker rates, but the overall distribution of flickers depends on the black hole mass. This is a much more reliable measure of size.

Interestingly, the team also applied their method to white dwarfs. These planet-sized solar mass stars can also have accretion disks, and the team found that their model applied to these accretion disks just as well. This suggests that the model describes something fundamental about accretion disks, not simply black holes. Because of this, the method could be applied to study elusive intermediate-mass black holes (IMBHs).

Where’s Waldo (or Where’s Wally) is a very popular book series for all ages.  One way to make it potentially more interesting is to adapt it to interplanetary exploration by searching for a Martian rover in a picture taken from a Martian helicopter.  Ingenuity took a picture on its eleventh flight that would be a worthy addition to any interplanetary search game – in this image, the goal is to find Perseverance.  

After its initial test flights were completed and proved that it was possible to have a controlled flight on Mars, the little drone has been busy scouting locations for Perseverance to take a look at.  It has stayed slightly in front of the rover as it explores the geology of the Séítah segment of Jezero crater, allowing Perseverance’s handlers to see potential locations of interest before directing the rover itself there.

But occasionally, the images Ingenuity snaps capture its traveling companion as well.  That was the case when Ingenuity took a shot of South Séítah and managed to catch Perseverance in the shot.  To find the rover, seek out Ingenuity’s shadow in the bottom center of the picture.  From there, go up almost to the top of the image and slightly to the right.  

There are a few pixels of bright white, which is the rover – primarily the Multi-mission Radioisotope Thermal Generator that is its power source. The zoomed-in picture NASA provided shows what the rover looks like, almost half a kilometer away from a height of 12 m.  

There are sure to be other instances of the helicopter scout taking images of Perseverance as the two continue their exploration of the crater.  But even a few years ago, such images were the stuff of science fiction.  Soon, someone could use them to make up their own picture book.