Tag: engineering

Leak search on ISS narrows further

9:25 am

Further work on ISS by the astronauts has now narrowed the location of the station’s long-term slow leak to the aft area of the Russian Zvezda module.

As of Monday, the station crew had not located the precise site of the leak, but officials believe they have traced it to a transfer compartment at the rear section of the Zvezda module, near an aft docking port where a Russian Progress resupply freighter is attached.

The rate of leak continues to be slow and thus not any danger to the crew. It is also a concern, as it could become a safety issue should it increase. They want to find it and patch it. Furthermore, Zvezda is ISS’s second oldest module, launched in 2000. If this leak is a sign of that age is even more essential to know.

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SpaceX launches another 60 Starlink satellites

8:20 am

After a number of weather delays, SpaceX this morning finally launched another 60 Starlink satellites into orbit, using its Falcon 9 rocket.

They also successfully landed the 1st stage, on its third flight, the 61st time they have done this. One fairing half was also making its third flight, and was also recovered. I have embedded the live stream of the launch below the fold.

The leaders in the 2020 launch race:

25 China
16 SpaceX
10 Russia
4 ULA
4 Europe (Arianespace)

The U.S. has retaken the lead from China, 26 to 25, in the national rankings.
» Read more

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Criss-crossing Martian ridges hit by new impacts

9:41 am

Criss-crossing Martian ridges hit by new impacts
Click for full image.

The image to the right, cropped to post here, is a captioned photo from the high resolution camera on Mars Reconnaissance orbiter and released today. From the caption:

The black spots [recent impacts] form because the craters exposed cleaner materials in the subsurface beneath the bright, dusty surface.

Our image is also interesting because the surface has a criss-cross pattern formed by wind activity. Bright ripples that are oriented from the upper right to the lower left are perpendicular to the wind flow. In contrast, outcrops that have been eroded by the wind are oriented perpendicular to the ripples to produce the criss-cross pattern we now observe.

The overview map below might also help explain this criss-cross pattern.
» Read more

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A donut on the Moon

8:58 am

A donut crater on the Moon
Click for full image.

In this case the donut is a crater dubbed Bell E Crater, with a second concentric rim in its interior. The photo to the right, reduced to post here, was taken by Lunar Reconnaissance Orbiter (LRO) as part of its high resolution survey of the entire Moon. As noted at the first link:

Craters not only vary in shape but also in complexity. There are simple craters and complex craters with ring structures and mountains at the center. Somewhere in between is Bell E, a small crater located within the larger Bell crater. These donut-shaped formations are commonly known as concentric craters. Many questions remain on the origin of donut craters. While there have been several ideas about their origin, including double impacts, the currently favored hypotheses involve volcanic processes and compositional variations.

The article outlines four hypotheses for explaining this crater’s formation, a perfectly aligned double impact, ripples at impact into thick warm lava, layers of different densities, and later volcanic activity. None do a good job of explaining all of the concentric craters found on the Moon, and thus suggest that these craters might have formed from some combination of more than one theory.

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Antares launches; Falcon 9 aborts

8:55 pm

Of the two launches scheduled for tonight, Northrop Grumman’s Antares rocket was the only one to launch, lifting off on schedule at 9:16 pm (Eastern). This was the company’s third launch this year.

SpaceX’s launch however aborted at T-2 seconds. No word on why the rocket’s computer’s shut down, or when they will reschedule.

The leaders in the 2020 launch race remain unchanged:

25 China
15 SpaceX
10 Russia
4 ULA
4 Europe (Arianespace)

The Antares launch however puts the U.S. back into a tie with China, 25-25, in the national rankings.

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Sunspot update: Practically no sunspots for a month

11:49 am

It is sunspot update time again! NOAA today updated its monthly graph for tracking the Sun’s monthly sunspot activity, and I have posted it below, with additional annotations by me to show the past solar cycle predictions.

July and August had seen sunspot numbers higher than the new NOAA prediction (shown by the red curve on the graph below). September however was almost totally blank, with only two weak sunspots for the entire month, as shown on the SILSO graph below.
» Read more

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Two launches scheduled for tonight, 27 minutes apart

9:08 am

The numerous launch scrubs this past week has created an unprecedented situation tonight, two orbital launches scheduled only 27 minutes apart from two different East Coast spaceports.

First Northrop Grumman will try again to launch its Cygnus cargo freighter to ISS from Wallops Island, Virginia, with the launch scheduled for 9:12 pm (Eastern). The first launch attempt last night was aborted 2:21 seconds before liftoff “after receiving off-nominal data from ground support equipment.”

Second, SpaceX will try to launch two Air Force GPS satellites from Cape Canaveral, Florida, with the launch scheduled for 9:43 pm (Eastern). This launch has been delayed several times because of the repeated launch scrubs of ULA’s Delta 4 Heavy rocket, attempting to launch a military reconnaissance satellite. ULA’s launch had priority for the range, but with it delayed due to the investigation over the T-7 second launch abort on September 30th, the SpaceX’s GPS launch moves up in line.

The first will be live streamed on NASA TV, the second by SpaceX. I have embedded the live streams for both below the fold.
» Read more

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Cygnus launch scrubbed less than 3 minutes from launch

6:49 pm

The scrubs keep coming! Northrop Grumman’s launch team tonight scrubbed the launch of its Antares rocket and Cygnus cargo freighter at T-2:21 minutes.

It appears, listening to the countdown, that the abort came from the engineers monitoring the propellants on the first stage, but this remains preliminary. More information is needed. (Update: It appears the issue was related to ground support equipment, not the rocket itself.)

They can recycle and launch tomorrow from Wallops Island, but this is also not confirmed. SpaceX also wishes to launch at almost the exact same time tomorrow from Cape Canaveral, and I am not sure both launches can occur simultaneously.

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Starship prototype #8 on launchpad

10:19 am

Capitalism in space: The eighth Starship prototype, with landing flaps (looking just like fins) has now been moved to its launchpad in preparation for static fire tests followed by a 50,000 foot or nine mile hop.

According to Elon Musk, SpaceX will static fire SN8 twice before attempting its 15 km (~50,000 ft) launch debut. More likely than not, SpaceX will attempt a triple-engine static fire with the Starship as-is, install SN8’s nosecone and forward flaps, and attempt a second static fire while only drawing propellant from tbe rocket’s smaller header tanks (one of which is located in the tip of its nose).

Previously the hop was supposed to go to 60,000 feet, or 11 miles. It appears they’ve scaled it back slightly.

If all these tests go well, the company’s license for the flight opens as soon as October 11th, though it is likely it will not happen quite that soon. More likely by the end of the month, or early in November. Regardless, the prototype looks quite impressive with its flaps, and in fact is now beginning to resemble a spaceship, not a silo.

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Crew for next Dragon manned flight name capsule “Resilience”

10:11 am

Capitalism in space: The crew for next Dragon manned flight, scheduled now for October 31st, have given the capsule the name “Resilience.”

Before arriving at Resilience, Hopkins and his crewmates filled a whiteboard with a long list of “good ideas” for their spacecraft’s name and then narrowed down their choices, he said.

“We wanted to make sure that the name fit,” Hopkins said in an interview with collectSPACE, following Tuesday’s press conference. “We got it down to two or three names and they were all very close in terms of that we liked them and could have been really happy with them, [but] at the end of the day, it was the one that just felt right.”

The crew of the first Dragon manned capsule named it Endeavour, to honor the shuttle spacecraft they had both flown in. The names of these capsules is not merely symbolic. Both capsules will be reused, like the shuttles, and thus deserve names to mark them when they fly again.

What is not clear yet is exactly how many capsules SpaceX will build, nor exactly how many times each capsule will be reused. The latter will of course help determine the former. It will take a few years and multiple flights to find out. Eventually however SpaceX will have its own fleet of manned spaceships, available not only to NASA but to private customers.

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Firefly completes static fire test of its Alpha first stage

10:02 am

Capitalism in space: Firefly Aerospace today released video footage showing the first successful static fire test of the first stage of its Alpha rocket.

I have embedded one of the videos, showing the test from multiple camera angles, below the fold.

The test is very impressive, and suggests strongly that they are on schedule to meet their target launch date for their first orbital test flight sometime between November ’20 and May ’21. It also suggests that this dark horse smallsat rocket company, once considered dead after filing for bankruptcy, might actually beat to orbit its closest competitors, Virgin Orbit and Astra. The latter two have already completed their first launch attempts, but both ended in failure.

Regardless, it appears the race between these three rocket companies is tightening. In fact, I wouldn’t be surprised if all three achieve their first orbital launches in the six to eight months.
» Read more

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Parker completes record-setting sixth Sun fly-by

9:51 am

The Parker Solar Probe has successfully completed its sixth close fly-by of the Sun, flying as close as 8.4 million miles, the closest any spacecraft has ever gotten to the Sun, while also moving at a record speed of 289,927 miles per hour.

Flight controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a “Status A” signal from the spacecraft through NASA’s Deep Space Network at 4:45 a.m. EDT; Status A is the best of four possible status signals, and indicates that the spacecraft is operating nominally.

The beacon comes after a six-day stretch when communications with the spacecraft were not possible as it wheeled around the Sun. This is the first sign of a successful solar encounter; this sixth solar encounter began Sept. 21 and continues through Oct. 2.

Future fly-bys will likely break this record as well.

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SpaceX launch aborts at T-18 seconds

9:00 am

Capitalism in space: SpaceX’s attempt to launch another 60 Starlink satellites today aborted at T-18 seconds due to what they called “out-of-family ground sensor reading.”

They have not announced a new launch date as yet.

The U.S. has had little luck getting any of its launches off in the past month. Many have been delayed or scrubbed, for either technical reasons or weather. Hopefully tonight’s launch of Northrop Grumman’s Cygnus cargo freighter to ISS will avoid these issues and get off the ground.

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Endless technical issues force Delta 4 Heavy launch scrubs

9:10 pm

BUMPED and revised to include the September 30th launch abort.

Can we count the ways? For what has become a string of seemingly endless technical issues, ULA on September 29th was forced to once again scrub the launch of a military reconnaissance satellite because of a technical issue with its Delta 4 Heavy rocket and launchpad.

Apparently when they tried to move the launchpad’s mobile gantry away from the rocket they discovered “a hydraulic leak in the ground system.”

On the evening of September 30th (tonight) they tried again, only to have an abort at T-7 seconds, just as the engines were to ignite as planned.

They have been trying to get this bird off the ground now for more than a month. Here is a chronology of the launch scrubs, with all the various technical issues described.

August 26: Scrub because of “several problems,” the primary cause being a “pneumatics system issue.” This same countdown also had a long hold because of two blown fuses in a launchpad heater.

August 29: Aborted at T-3 seconds, due to “a torn diaphragm in one of three pressure regulators” in the launchpad. During the countdown they also had holds to deal with a fuel valve issue, a fuel sensor issue, and a temperature payload issue.

September 26: Scrubbed because of issue with the launchpad “swing arm retraction system.”

September 27: Scrubbed because of a continuing issue with the launchpad “swing arm retraction system.”

September 29 (just after midnight): A lightning strike forced a scrub. This was the only scrub not caused by technical issues.

September 29 (just before midnight): Scrubbed because of a hydraulic leak in the ground system.

September 30: Aborted at T-7 seconds. Under investigation. No new launch date yet announced.

This string of seemingly minor and apparently easy-to-fix problems does not reflect well on the quality control systems at ULA. I understand that this is rocket science, and thus difficult. At the same time engineers have now been doing launches for more than a half century, and this tale of woe above is more reminiscent of the early days of rocketry in the 1960s, when you might have a dozen or more scrubs because of these kinds of technical issues. You’d think by now ULA’s launch engineers would have worked these kinks out.

From a customer perspective this list of issues is also troubling, considering that the Delta 4 Heavy costs the customer more than any other commercial rocket. Granted it can put up a lot of payload, but the Falcon Heavy can put up more, and do it for less than half the cost and far more reliably. If I was ULA’s customer I would not be very satisfied with the product I am getting, even if the launch turns out to be a complete success.

The delays are also impacting other launches. SpaceX has had to repeatedly delay the launch of a GPS satellite on its Falcon 9 because for scheduling reasons the ULA launch must come first.

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Changes in engineering and procedures for next manned Dragon flight

4:27 pm

SpaceX is making several engineering and operational changes involving flights of its manned Dragon capsule, based on the company’s experience during the first manned flight several months ago.

First, they are reinforcing the heat shield in one area.

After a successful test flight that ended when NASA astronauts Bob Behnken and Doug Hurley splashed down in the Gulf of Mexico on Aug. 2, the company noticed “a little more erosion than we wanted to see” in a few areas of the capsule’s heat shield, Hans Koenigsmann, SpaceX’s vice president of build and flight reliability, said during a press call this week. He said there “was nothing to be concerned with at all times. The astronauts were safe, and the vehicle was working perfectly.”

Second, they are revising the software used to determine the altitude when the capsule’s drogue parachute is released.

Koenigsmann said the company is refining how it measures the capsule’s altitude as it returns to Earth. During the August test flight, the drogue parachutes deployed at a slightly lower altitude than the company expected, but still well within safety parameters, he said.

Finally, they are going to more strictly enforce a 10-mile “keep-out zone” in the ocean where the capsule splashes down. They do not want to see another crowd of recreational boats swarming the landing zone, as happened when the capsule returned to Earth in August.

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Leak on ISS located?

3:57 pm

According to Business Insider article , engineers have finally narrowed the location of the slow leak on ISS to the Russian Zvezda module.

NASA and Roscosmos, Russia’s space agency, had already narrowed down the likely location of the leak to several modules on the station’s Russian side.

So astronaut Chris Cassidy and cosmonauts Anatoly Ivanishin and Ivan Vagner tested those modules by shutting the hatches between each one and using an ultrasonic leak detector to collect data through the night. The tool measures noise caused by airflow too quiet for humans to hear.

By Tuesday morning, they’d figured out that the leak is in the Zvezda Service Module, the main module on the station’s Russian side. Zvezda provides that half of the station with oxygen and drinkable water, and it’s also equipped with a machine that scrubs carbon dioxide from the air. The module contains the section’s sleeping quarters, dining room, refrigerator, freezer, and bathroom.

They don’t yet know where in the module the leak is located, but at least they know at last where to look.

This module was the second module launched to ISS, launching in 2000. Thus, the leak could not have come from any construction workers from the ground. More likely its age has resulted in something changing. This needs to be fixed, but at the moment the situation is not critical.

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On the rim of Mars’ Grand Canyon

9:35 am

The rim of Valles Marineris
Click for full image.

Cool image time! Mars has many grand geological features that will surely attract tourists in the far future, when the planet has been successfully colonized and humans live there with the same ease that we today live in what was the New World wilderness several hundred years ago.

Of those features, none probably compare with Valles Marineris, the largest known canyon in the solar system. When compared to it, the Grand Canyon — at about a mile deep, about ten miles wide, and about 280 miles long — is a mere pothole, hardly noticeable. Valles Marineris averages a depth of five miles, a width of 370 miles, and a length of 1,900 miles. You could fit many Grand Canyons within it.

The photo to the right, cropped to post here, was taken on July 13, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows only a tiny section of this gigantic canyon’s rim. At this spot the depth from rim to floor is about 4.3 miles, or about 22,700 feet. In the image itself I estimate the cliff at the rim to be somewhere between 6,000 to 8,000 feet high, more than the depth of the entire Grand Canyon. And that’s only this top cliff.

The three overview maps below show the context of this location within Valles Marineris.
» Read more

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Big scallops in the Martian southern latitudes

12:11 pm

Big scallops on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, shows an example of some large scalloped depressions in the high southern latitudes of Mars.

Taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on June 27, 2020, these scallops resemble in many ways the ice scarps that scientists have previously found at this same latitude, both to the east and west of where these scallops are located. With those scarps, the data suggests that a very pure layer of ice is visible in the cliff face, and that over time the cliff retreats northward due to sublimation of that ice.

The scallops in the photo to the right suggest the same process, though the differences raise questions. As explained by Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona,
» Read more

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The liquids in Titan’s lakes stratify into different density layers

9:50 am

Using the data archive from the Cassini mission to Saturn, scientists now think that the liquids in Titan’s lakes can stratify into different density layers.

Lakes on Saturn’s moon Titan, composed of methane, ethane, and nitrogen rather than water, experience density driven stratification, forming layers similar to lakes on Earth. However, whereas lakes on Earth stratify in response to temperature, Titan’s lakes stratify solely due to the strange chemical interactions between its surface liquids and atmosphere, says a paper by Planetary Science Institute Research Scientist Jordan Steckloff.

Stratification occurs when different parts of a lake have different densities, with the less dense layer floating atop the denser layer. On Earth, lakes in temperate climates often stratify into layers in the summer as the Sun heats the surface of the lake, causing this water to expand and become less dense, forming a layer of warm water that literally floats upon the cooler water below. This density-driven stratification can occur on Titan as well; however it happens due to the amount of atmospheric nitrogen that Titan’s surface liquids can dissolve, rather than the liquids warming up and expanding.

…Because liquid methane is less dense than liquid ethane, it has been long assumed that Titan’s methane would generally float atop its liquid ethane. However, when methane’s affinity for atmospheric nitrogen is accounted for, methane can dissolve sufficient nitrogen at low temperatures to become denser than ethane.

This result has a great deal of uncertainty, mostly because of the relatively small dataset available of Titan. What it really shows is the possibility of this phenomenon. To confirm it will require some in situ measurements.

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NASA & SpaceX set Oct 31st for next manned Dragon mission

9:22 am

Capitalism in space: NASA and SpaceX have now scheduled Oct 31st as the target launch date for the first operational manned Dragon mission to ISS, the second manned Dragon mission overall.

This new date delays the launch a week from the previous announced schedule, and was done to give some space between its launch and the launch of a manned Soyuz on October 14th and the return of a different Soyuz with the present ISS crew on October 21st.

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UAE leader confirms goal to land rover on Moon by ’24

9:15 am

The new colonial movement: The ruler of the United Arab Emirates (UAE) has confirmed the initiation of a project to land a rover on the Moon by 2024, and have it built entirely by UAE engineers.

The Emirates Lunar Mission will be a 100 percent Emirati-built lunar rover that will land on the moon by 2024, according to a series of tweets by Sheikh Mohammed bin Rashid Al Maktoum, the UAE Prime Minister and Vice President and Ruler of Dubai.

The lunar rover has been named “Rashid” in honour of Sheikh Rashid bin Saeed Al Maktoum who ruled Dubai for 32 years from 1958 until his death in 1990 and who “sparked” the emirate’s advancement.

This is an ambitious goal, but not completely unreasonable. Their engineers were closely involved in the construction of their Hope Mars orbiter, mostly built by U.S. universities and subcontractors. That knowledge can now be applied to their own spacecraft. I also suspect that their 2016 agreement with India to invest billions there in exchange for space-related engineering assistance included technical information about India’s own lunar rover missions.

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ISS air leak still unlocated

9:04 am

The small air leak that was found on ISS a year ago has still not been located, despite a second weekend where the crew isolated themselves in one module and closed the hatches on all other modules so that ground engineers could track any air supply changes.

At a Sept. 28 briefing about the upcoming Northrop Grumman NG-14 Cygnus cargo mission to the station, a NASA official said that the weekend isolation in the Zvezda module failed to immediately locate the source of the leak. “As of this morning, there was no clear indication of where the leak is,” said Greg Dorth, manager of the ISS Program External Integration Office at NASA. “The teams are still looking at the data and evaluating it.”

This was the second time the ISS crew confined themselves to Zvezda in an effort to track down the leak. A month earlier, the three also spent a weekend in Zvezda with the other modules sealed off in an effort to locate the leak. “After the three days, there was no indication of where the leak was coming from,” Dorth said.

This latest test, he said, featured some “slightly different configurations” in both the U.S. and Russian segments, although he did not elaborate on the differences between the two tests. In addition, Cassidy used an ultrasonic leak detector to see if the leak was coming from Zvezda itself.

These tests were possible since mid-August because there were only three people on station, allowing them to be confined to one module for a period of time. Moreover, during this time no other spacecraft have arrived or left. It is suspected that the leak is most likely coming from the connection point between two modules, and adding or removing a Soyuz, Dragon, or freighter to the station shifts its center of gravity, changing the stress points at those connections.

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New study confirms liquid water under Mars’ south pole

3:02 pm

A new study has confirmed earlier work that suggested there were liquid lakes of water under the Martian south pole.

The data appears to indicate that the bodies are “hypersaline solutions” –a brine in which high concentrations of salt are dissolved in water – which is perhaps the reason they are able to stay liquid despite the very cold conditions of Mars’s south pole.

The fact that there is a whole set of lakes suggests that they have probably formed relatively easily, and that versions of them may therefore have been present throughout the history of the planet. [emphasis mine]

There is one problem with hypothesis indicated by the highlighted words. Mars’ rotational tilt (its obliquity) shifts significantly, from 0 to 60 degrees. Right now it is tilted about 25 degrees, similar to Earth. The south pole as we see it today will have been very different at different obliquities, which means there is no way to assume these posited underground lakes would have been there.

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Martian channels formed by water? by ice? by lava?

1:37 pm

Meandering channels on Mars
Click for full image.

Many of the pictures from Mars show meandering channels, all of which suggest an erosion process related to some form of flow. For most of the last half century, since the first images of these channels were beamed back by Mariner 9 in 1972, scientists had believed that liquid water must have caused them. The accumulating recent photos from Mars now tentatively suggest that these channels might have instead been caused by glacial processes, creeping frozen water instead of liquid.

The image to the right, rotated, cropped, and reduced to post here, was taken on July 17, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. The channels suggest some form of flow going downhill to the northwest, but was it caused by water or ice? There is no obvious visual evidence of glaciers in this image, nor is there any such evidence that I can spot in any of the nearby high resolution images of this same region, despite the fact that at 35 degrees north latitude it is in the mid-latitude band where scientists have identified many glacial features.

The region itself is called Mareotis Fossae, an area of southwest-to-northeast trending parallel fissures and ridges, as shown in the two overview maps below.
» Read more

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UAE outlines new plans in space

8:57 am

The new colonial movement: The United Arab Emirates (UAE) had put forth a new set of goals in its space program, including sending another astronaut to space, sending an unmanned probe to the Moon, and encouraging the development of UAE-built Earth resource smallsats.

The lunar mission is targeted to launch in 2024, and it appears they wish to build it entirely themselves, rather than subcontract American companies and universities to do the bulk of the work, as they did for the Hope Mars orbiter. It appears they believe that the training their people got from the Hope mission development will make it possible for them to proceed now on their own.

I also suspect that instead of buying a Russian Soyuz launch, they are aiming to hire an American company, either SpaceX or Boeing, to fly their next astronaut, since they have made a deal with NASA for astronaut training.

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China and Russia launch a bunch of satellites

8:40 am

Russia today used its Soyuz-2 rocket to launch three communication satellites plus 19 commercial smallsats.

This was the first time Russia used the Soyuz-2 for these particular small communications satellites, as previously they had been launched by a variety of smaller rockets.

China in turn today used its Long March 4B to place two Earth resource satellites into orbit.

The leaders in the 2020 launch race:

25 China
15 SpaceX
10 Russia
4 ULA
4 Europe (Arianespace)

China has moved ahead of the U.S. 25 to 24 in the national rankings.

These numbers should change again in the next few days. The U.S. has had a number of scrubs and launch delays in the past few days. ULA has been repeatedly pushing back the previously delayed launch of a National Security Agency reconnaissance satellite due to a variety of problems related to its Delta 4 Heavy rocket. The launch is now set for just after midnight tonight (Monday night). [UPDATE: Launch scrubbed due to lightning and poor weather. Tentatively rescheduled for 11:58 pm (Eastern) on September 29.]

SpaceX meanwhile had to scrub a launch this morning (September 28) of another 60 Starlink satellites due to weather. No new launch date has yet been announced.

Northrop Grumman also has had to scrub tomorrow’s Antares launch of a Cygnus cargo freighter because of poor weather at Wallops Island. It is now set for the evening of October 1st.

SpaceX also has a scheduled launch tomorrow morning of a GPS satellite on its Falcon 9 rocket. This is also threatened by weather. There is also no word whether the ULA launch scrub will cause this launch to be delayed.

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German instrument on Chang’e-4 documents dangerous radiation levels

2:07 pm

This result is not a surprise: A German instrument on China’s Chang’e-4 lander, located now on the Moon’s far side, has measured the radiation levels there, and found them to be much worse than found on Earth.

DLR radiation physicist Thomas Berger from the DLR Institute of Aerospace Medicine, who participated in the publication explains: “The radiation exposure we measured is a good indication of the radiation inside a spacesuit. The measurements give us an equivalent dose rate – the biologically weighted radiation dose per unit of time – of around 60 microsieverts per hour. For comparison, during a long-haul flight from Frankfurt to New York, the dose rate is five to 10 times lower than this. On Earth’s surface, it is some 200 times lower. In other words, a long-term stay on the Moon will expose astronauts’ bodies to high doses of radiation.”

“Human bodies are simply not made to be exposed to space radiation,” adds Robert Wimmer-Schweingruber of the Christian-Albrecht University (CAU) in Kiel, whose team developed and built the LND instrument . “On longer missions to the Moon, astronauts will have to protect themselves from it – by covering their habitat with a thick layer of lunar rock, for example. This could reduce the risk of cancer and other illnesses caused by long periods of time spent on the Moon.”

Previous instruments had only measured the cumulative radiation for the entire mission. This instrument took multiple readings lasting one, ten, or sixty minutes, which gives a more realistic measure of what an astronaut would actually experience, once there.

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An ice-covered mountain on Mars?

2:00 pm

Ice-covered mountain on Mars?
Click for full image.

Grinnell Crater in Glacier National Park in 2017

Today’s cool image, taken on July 1, 2020 by the high resolution camera on Mars Reconnaissance Orbiter, is of a mound-like mountain on Mars that to all intents and purposes appears covered by glacial ice, some eroded, some not.

The image to the right, rotated, cropped, and reduced to post here, shows this mound. Both the flow coming down from the mountain top down the north slope as well as the flow in the north that appears to begin in a small crater suggest glacial features.

Even more convincing are what appear to be patches of glacial ice on the southern slopes, resembling the kind of glacial patches you see everywhere in Glacial National Park. The second photo to the right, taken by me on our visit to Glacier National Park in 2017, shows similar patches hugging the mountainside at Grinnell Glacier.

This Martian mountain is located in the southern hemisphere inside Hellas Basin on its eastern interior rim. (See the overview map below, with the location of this photo the small white box south of Harmakhis Valles.) Thus, you would expect the north-facing slope to get more sunlight (and more heat) than the south-facing slopes. Yet, from this image there appears to be greater erosion on the south-facing slopes. A puzzle indeed.
» Read more

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