What Is Worth Saving?

November 14, 2020 by Elliot Williams 72 Comments

When it rain, it pours. One of the primary support cables holding up the Arecibo Observatory dish in Puerto Rico has just snapped, leaving its already uncertain fate. It had been badly damaged by Hurricane Maria in 2017, and after a few years of fundraising, the repairs were just about to begin on fixing up that damage, when the cable broke. Because the remaining cables are now holding increased weight, humans aren’t allowed to work on the dome until the risk of catastrophic failure has been ruled out — they’re doing inspection by drone.

Arecibo Observatory has had quite a run. It started out life as part of a Cold War era ICBM-tracking radar, which explains why it can transmit as well as receive. And it was the largest transmitting dish the world had. It was used in SETI, provided the first clues of gravitational waves, and found the first repeating fast radio bursts. Its radar capabilities mean that it could be used in asteroid detection. There are a number of reasons, not the least of which its historic import, to keep it running.

So when we ran this story, many commenters, fearing the worst, wrote in with their condolences. But some wrote in with outrage at the possibility that it might not be repaired. The usual suspects popped up: failure to spend enough on science, or on infrastructure. From the sidelines, however, and probably until further structural studies are done, we have no idea how much a repair of Arecibo will cost. After that, we have to decide if it’s worth it.

Per a 2018 grant, the NSF was splitting the $20 M repair and maintenance bill with a consortium led by the University of Central Florida that will administer the site. With further damage, that might be an underestimate, but we don’t know how much of one yet.

When do you decide to pull the plug on something like this? Although the biggest, Arecibo isn’t the only transmitter out there. The next largest transmitters are part of Deep Space Network, though, and are busy keeping touch with spacecraft all around our solar system. For pure receiving, China’s FAST is bigger and better. And certainly, we’ve learned a lot about radio telescopes since Arecibo was designed.

I’m not saying that we won’t shed a tear if Arecibo doesn’t get repaired, but it’s not the case that the NSF’s budget has been hit dramatically, or that they’re unaware of the comparative value of various big-ticket astronomy projects. Without being in their shoes, and having read through the thousands of competing grant proposals, it’s hard to say that the money spent to prop up a 70 year old telescope wouldn’t be better spent on something else.

After Eight-Month Break, Deep Space Network Reconnects With Voyager 2

November 12, 2020 by Dan Maloney 48 Comments

When the news broke recently that communications had finally been re-established with Voyager 2, I felt a momentary surge of panic. I’ve literally been following the Voyager missions since the twin space probes launched back in 1977, and I’ve been dreading the inevitable day when the last little bit of plutonium in their radioisotope thermal generators decays to the point that they’re no longer able to talk to us, and they go silent in the abyss of interstellar space. According to these headlines, Voyager 2 had stopped communicating for eight months — could this be a quick nap before the final sleep?

Thankfully, no. It turns out that the recent blackout to our most distant outpost of human engineering was completely expected, and completely Earth-side. Upgrades and maintenance were performed on the Deep Space Network antennas that are needed to talk to Voyager. But that left me with a question: What about the rest of the DSN? Could they have not picked up the slack and kept us in touch with Voyager as it sails through interstellar space? The answer to that is an interesting combination of RF engineering and orbital dynamics.

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Spacing Out: A Big Anniversary, Starlink Failures Plummet, Lunar Cellphones, And A Crewed Launch

November 11, 2020 by Jenny List 32 Comments

After a couple of months away we’re returning with our periodic roundup of happenings in orbit, as we tear you away from Star Trek: Discovery and The Mandalorian, and bring you up to date with some highlights from the real world of space. We’ve got a launch to look forward to this week, as well as a significant anniversary.

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Sending 3D Printed Parts To Mars: A Look Inside JPL’s Additive Manufacturing Center

November 10, 2020 by Dan Maloney 5 Comments

With the Mars 2020 mission now past the halfway point between Earth and its destination, NASA’s Jet Propulsion Lab recently released a couple of stories about the 3D-printed parts that made it aboard the Perseverance rover. Tucked into its aeroshell and ready for its high-stakes ride to the Martian surface, Perseverance sports eleven separate parts that we created with additive manufacturing. It’s not the first time a spacecraft has flown with parts made with additive manufacturing technique, but it is the first time JPL has created a vehicle with so many printed parts.

To take a closer look at what 3D-printing for spaceflight-qualified components looks like, and to probe a little into the rationale for additive versus traditional subtractive manufacturing techniques, I reached out to JPL and was put in touch with Andre Pate, Additive Manufacturing Group Lead, and Michael Schein, lead engineer on one of the mission’s main scientific instruments. They both graciously gave me time to ask questions and geek out on all the cool stuff going on at JPL in terms of additive manufacturing, and to find out what the future holds for 3D-printing and spaceflight.

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Watching The Global Oil Trade With Satellite Imagery

November 9, 2020 by Danie Conradie 10 Comments

The global oil market plays a large role in the geopolitical arena, and it is often in the interest of various role players to conceal the figures on production, consumption and movement of oil. This may simply to be to gain an advantage at the negotiation tables, or to skirt around international sanctions. The website [TankerTrackers] is in the business of uncovering these details, often from open source intelligence. Using satellite imagery, they are using a simple way to monitor the occupancy crude oil storage facilities around the world.

The key is in the construction of large capacity crude oil storage tanks. To prevent the flammable gasses emitted by crude oil from collecting inside partially empty tanks, they have roofs that physically float on top of the oil, moving up and down inside the steel sides as the levels change. By looking at imagery from the large number of commercial satellites that constantly photograph earth’s surface, one can determine how full the tanks are by comparing the length of a shadow inside the tank to the shadow outside the tank. Of course, you also need to know the diameter and height of a tank. Diameter is easy, just use Google Earth’s ruler tool. Height is a bit more tricky, but can often be determined by just checking the facilities’ website for ground level photos of the tanks. Of course these methods won’t give you exact numbers, but it’s good enough for rough estimates.

Another interesting detail we found perusing the [TankerTrackers] news posts (requires sign-up) is that tankers will sometimes purposefully switch off their AIS transponders, especially when heading to and from sanctioned countries such as Venezuela and Iran. Even in today’s world of omnipresent tracking technologies, it’s surprisingly easy for a massive ship to just disappear. Sometimes [TankerTrackers] will then use imagery to track down these vessels, often by just watching ports.

Thanks for the tip [Arpad Toth]!

Photo by [Terryjoyce] CC BY-SA 3.0

Hello From The NearSpace

November 9, 2020 by Matthew Carlson 6 Comments

A key challenge for any system headed up into the upper-atmosphere region sometimes called near space is communicating back down to the ground. The sensors and cameras onboard many high altitude balloons and satellites aren’t useful if the data they collect can’t be retrieved. Often times, custom antennas or beacons are added to help. Looking at the cost and difficulty of the problem, [arko] and [upaut] teamed up to try and make a turn-key solution for any near-space enthusiast by building CUBEX, a wonderful little module with sensors and clever radio that can be easily reused and repurposed.

CUBEX is meant as a payload for a high-altitude balloon with a camera, GPS, small battery, solar cell, and the accompanying power management circuits. The clever bit comes in the radio back down. By using the 434.460 Mhz band, it can broadcast around a hundred miles at 10mW. The only hardware to receive is a radio listener (a cheap RTL USB stick works nicely). Pictures and GPS coordinates stream down at 300 baud.

Their launch was quite successful and while they didn’t catch a solar eclipse, their balloon reached an impressive 33698m (110,560ft) while taking pictures. Even though it did eventually splashdown in the Pacific Ocean, they were able to enjoy a plethora of gorgeous photos thanks to their easy and cost-effective data link.

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Lunar Ark Boldly Goes

November 6, 2020 by Matthew Carlson 27 Comments

[Sebastian and Karl-Johan] are two award-winning Danish Space Architects who are subjecting themselves to harsh, seemingly uninhabitable conditions, for science. The pair set out to build a lunar base that could land with the manned Moon missions in 2024. Like any good engineering problem, what good is a solution without testing? So the pair have placed their habitat in a Moon Analogue habitat and are staying in their habitat for two months. They want to really feel the remoteness, the bitter cold, and the fatigue of actually being on the moon. So far they are about halfway through their journey and expect to return home in December 2020.

When asking themselves where on Earth is it most like the Moon, they came up with Moriusaq, Greenland. It’s cold, remote, in constant sunlight this time of year, and it is a vast white monochrome landscape just like the moon. The first moon settlement missions are expected to be at the South Pole of the Moon, as known as the Peak of Eternal Light.
The habitat itself is a testament to the duo’s ingenuity. The whole structure folds to fit the tight space and weight requirements of rockets. Taking 2.9m³ (102 ft³) when stored, it expands 560% in volume to 17.2m³ (607 ft³). In Greenland, the structure needs to withstand -30ºC (-22ºF) and 90 km/h winds.

Because the South Pole is in constant sunlight, the temperature varies much less there than on the rest of the Moon, which makes Greenland a very good analogue temperature-wise. The foldable skin is covered in solar panels, both on the top of the bottom. The highly reflective nature of the Moon’s surface makes it easy to capture the light bouncing up onto the bottom of the habitat.

Several other bits of technology have been included onboard, like a 3D printer, a circadian light stimulation system, an algae reactor, and a weather simulation. Since both the Moon and Greenland are in constant sunlight, the pod helps regulate the circadian rhythms of the occupants by changing the hue and brightness throughout the day. The weather simulation tries to break up the monotony of space by introducing weather like a stormy day or rainbow colours.

Their expedition is still ongoing and they post daily mission updates. While some might call their foray into the unknown madness, we call it bold. Currently, NASA is planning its Artemis mission in 2024 and we hope that the lessons learning from the Lunark and other experiments culminate in a better experience for all astronauts.