One of the great things about CubeSat designs is that they constrain the engineers who design them. Constraints are a great way to develop novel solutions to problems that might otherwise be ignored without them. As CubeSats become increasingly popular, more and more researchers are looking at how to get them to do more with less. A paper from 2020 contributes to that by designing a 3U CubeSat mission that weighs less than 4 kilograms to perform a fly-by of a Near Earth Asteroid (NEA) using entirely off-the-shelf parts. The research, carried out by a team based at the Delft University of Technology, had several mission requirements they were trying to meet. Some were standard like it had to have a propulsion system and a way to get data back to Earth. However, some were more challenging – it had to weigh less than 4 kg, it had to fit into a 3U CubeSat body (which measures (100mm x 100mm x 340.5mm), it had to perform its mission in less than 650 days, and, perhaps the most technically challenging goal – it has to “exploit a fully-autonomous navigation strategy.” First, let’s look at the mission design. Since there are around 35,000 known NEAs, mission designers would be spoiled for choice. However, getting to one with a relatively limited propulsion budget (since propellant increases the weight – one of the design constraint limits) and finding the right one would require extensive searching of the JPL Small-Body Database.  Fraser discusses how we find NEAs Once an NEA has been selected, the mission designers could plan the optimal trajectory. However, to meet the requirement of an autonomous navigation strategy, the CubeSat itself will have to find its way to the asteroid and enact any course corrections along the way. This could be extremely difficult, given the low brightness of many of the target asteroids and how that brightness might change based on what side of it is facing the Sun and what angle the CubeSat is approaching it from. The scientific payload, including a visible light and IR camera, would have to work in tandem with a micro star tracker to ensure the trajectory is optimal for scientific data collection. That data collection might only last a few minutes, as the limited propellant for the mission would require it to be a fly-by rather than an orbit. The resulting image might be as small as a 6 x 6 pixel image for a 300m diameter asteroid. This would provide orders of magnitude with more resolution than ground-based observations for most. Still, it would not be enough to get into the details of mass and composition that planetary protectors and asteroid mining enthusiasts alike would most desire. Any new information is better than no information, though, and the simplicity of the design for this mission’s hardware makes it relatively inexpensive and, therefore, mass-producible. It consists of six major sub-systems – the “payload,” which is essentially a visible light and infrared camera; the propulsion system, which is a microjet ion propulsion engine; the attitude determination and control system (ADCS), which helps navigate; a communication system that uses an X-band antenna to communicate back to the Deep Space Network infrastructure, and a power system that would involve deployable solar panels.  Some of the engineering that goes into CubeSats is pretty impressive, as this JPL video shows.Credit – NASA Jet Propulsion Laboratory YouTube Channel Overall, the mission met the goal of fitting entirely into a 3U package and came in at 3.8kg using off-the-shelf components. However, thermal management systems and radiation shielding were not considered in the design. Other challenges, like getting time on the already overstretched Deep Space Network ground antennas, are left for another paper. But if nothing else, this paper proves that it is possible, on paper at least, to design an inexpensive mission to collect data on an asteroid and that that mission can be replicated hundreds or even thousands of times at relatively low cost. As CubeSats gain more and more capabilities and more and more traction, and as launch costs get lower and lower, it’s becoming increasingly plausible that someday, a system like this might very well make its way past an asteroid and send data back that we otherwise wouldn’t have gotten. Learn More:Casini et al – Novel 3U Stand-Alone CubeSat Architecture for Autonomous Near Earth Asteroid Fly-ByUT – A Pair of CubeSats Using Ground Penetrating Radar Could Map The Interior of Near Earth AsteroidsUT – A Mission To Find 10 Million Near Earth Asteroids Every YearUT – Swarms of Orbiting Sensors Could Map An Asteroid’s Surface Lead Image:ESA’s Hera Mission is joined by two triple-unit CubeSats to observe the impact of the NASA-led Demonstration of Autonomous Rendezvous Technology (DART) probe with the secondary Didymos asteroid, planned for late 2022. Credit: ESA The post A 3U CubeSat Could Collect Data During an Asteroid Flyby appeared first on Universe Today.

Our understanding of the Universe is profound. Only a century ago, astronomers held a Great Debate to argue over whether our galaxy was an island universe, or whether nebulae such as Andromeda were galaxies in a much larger cosmos. Now we know that the Universe is billions of years old, ever expanding to billions of light-years across, and filled with not just stars and galaxies but with dark energy and cold dark matter. Astronomers summarize this understanding as the LCDM model, which is the standard model of cosmology. While the observational data we have strongly supports this model, it is not without its challenges. The most striking challenge is known as the Hubble tension. When we measure the rate of cosmic expansion in various ways, we can calculate what is known as the Hubble constant or Hubble parameter, which defines the rate of cosmic expansion. This rate also tells us things such as the age of the Universe and the average density of dark energy and matter. While the various observations generally cluster around 68-69 km/s/Mpc, several of the methods give results outside that range. There is some evidence to support the idea that the current rate of cosmic expansion is greater than that during the early Universe, which is known as cosmic shear tension. All of this means either some of our methods are in error somehow or there is a fundamental aspect of cosmic expansion we don’t yet understand. Related to this are the mysteries surrounding dark energy. Within the standard model, dark energy is a property of space and time and is universal throughout the cosmos. But there is an alternative view that holds dark energy is an independent scalar field within spacetime, sometimes referred to as quintessence. Observations such as the clustering scale of galaxies generally support the former model, but there are a few studies here and there that suggest the latter. We don’t yet have enough data to rule out either completely. Observations of the Hubble parameter. Credit: N. Palanque-Delabrouille Then, of course, there is the great bugbear of dark matter. Observations strongly support its existence, and that dark matter makes up most of the matter in the Universe. But within the standard model of particle physics, there is nothing that could comprise dark matter, and countless experiments trying to detect dark matter directly have so far yielded nothing. Alternative models such as modified gravity can account for some of our observations, but models must be tweaked just so to fit data, and no alternative approach agrees with all our observations. Dark matter remains central to the standard cosmological model, but its true nature remains in shadow. In short, we are tantalizingly close to a complete and unifying model of the Universe, but there are deep and subtle mysteries we have yet to solve. We need more theoretical ideas, and we desperately need more observational data. Fortunately, there are exciting projects in the pipeline that could solve these mysteries in the near future. One of these is the Dark Energy Spectroscopic Instrument (DESI) survey, which is currently underway. Over the course of the five-year project, DESI will observe the spectra of more than 35 million distant galaxies, giving us a detailed 3D map of the Universe. In comparison, the Sloan Digital Sky Survey (SDSS) gathered data on 4 million galaxies and gave us the most detailed view of galactic clustering at the time. With DESI, we will be able to see the interaction between dark matter and dark energy across billions of years and hopefully determine whether dark energy is constant or changes over time. Comparison of SDSS (left) with DESI (right). Credit: David J. Schlegel Another useful tool will be the Vera Rubin observatory, which should come online in a few months. By giving us a high-resolution map of the sky every few days, Rubin will allow us to study transient phenomena such as supernovae used to measure cosmic expansion. It will also give us a rich view of matter within our galaxy and could reveal aspects of how that matter interacts with dark matter. Further into the future, there are planned projects such as the Wide-field Spectroscopic Telescope (WST), which will expand on the abilities of Rubin observatory, and the Spec-S5, which will complement the DESI surveys. Both of these are still in the planning stage, but could become the DESI surveys. Both of these are still in the planning stage but could become operational within a decade or so. In the 1920s, the Great Debate of Astronomy was solved thanks to a wealth of data. The rise of photographic astronomy allowed us to see the Universe in transformative new ways and made modern cosmology possible. We are now entering an era of large data astronomy, where wide-field telescopes and large surveys will provide more data in an evening than could be gathered in a year just decades ago. Brace yourselves for another revolutionary era of astronomy. Reference: Palanque-Delabrouille, N. “Future directions in cosmology.” arXiv preprint arXiv:2411.03597 (2024). The post Cosmology is at a Crossroads, But New Instruments are Coming to Help appeared first on Universe Today.

'Christmas in the Heart' seemed to randomly arrive in 2009 from the Jewish songwriter. Continue reading…

Wow. A couple days ago, legendary and longtime harmonica player for Willie Nelson, Mickey Raphael, headlined a show at the Brooklyn Bowl in Nashville, Tennessee. If you're a Willie Nelson fan in any capacity, you're probably very familiar with Mickey... and if you're not, you should be. He was joined by plenty of other famous friends, from ZZ Top's Billy F Gibbons to the great Chris Stapleton, who joined him for a gorgeous rendition of "Georgia On My Mind." Of course, the classic song was written by Hoagy Carmichael and Stuart Gorrell and first recorded that same year by Carmichael. But of course, Ray Charles, a Georgia native, made it a massive hit and all-time classic when he recorded it for his 1960 The Genius Hits the Road album. The Ray Charles original is actually the official state song of Georgia, but obviously, if you’re a country music fan (and I’m assuming you are if you’re reading this), then you probably associate it closely with the great Willie Nelson as well. When Willie decided to record his iconic Stardust album in 1978, which was full of pop standards and produced by Booker T. Jones, his cover become a hit and shot to #1 on the country charts. In 1979, Willie won the Grammy Award for Best Male Country Vocal Performance because of the song. The harmonica on so many of Willie's songs, but this one in particular, is instantly recognizable for fans, and it's all thanks to the great Mickey Raphael, who has been with Willie since 1973, when he was just twenty-one years old. He now also tours with Stapleton, and if there's any two people who could really do this song justice in these modern times, it's Mickey and Chris. Of course, Chris could sing the phone book and make it sound like a hit, and I could listen to him sing the classics all day long... seriously, I can't get enough. Proceeds from the event benefitted Chris and Morgane Stapleton's charity, Outlaw State of Kind, and you can watch their simple and stunning performance here: https://www.youtube.com/watch?v=GkJI4z26i_Y The Willie Nelson Stardust version: https://www.youtube.com/watch?v=YMxdr78y-E4 Of course, Chris is no stranger to covering Willie Nelson songs, and he's done stellar covers of two of my all-time favorite songs before in "Last Thing I Needed, First Thing This Morning" and "Always On My Mind." The former was included as a studio cut on his 2016 From A Room: Volume 1 album, and was eventually certified Gold by the RIAA. The latter was done more recently, when Chris performed at Willie's star-studded 90th birthday celebration Long Story Short: Willie Nelson 90 Live At The Hollywood Bowl. It was obviously one of the best performances of the entire event, and I am still blown away but what he did with it and how powerful, yet understated, it was. Stapleton has a powerhouse voice, but he knows when to let it rip and also when a song calls for something a little more subdued, which is part of what makes him such a special talent. If you haven't ever heard these covers before, then you have been sorely missing out... and it's high time to change that. "Always On My Mind" https://www.youtube.com/watch?v=RpAlDT-SyNg "Last Thing I Needed, First Thing This Morning" https://www.youtube.com/watch?v=bi9iBKa0Xtw&embeds_referring_euri=https%3A%2F%2Fwww.whiskeyriff.com%2F&source_ve_path=MjM4NTE

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President-elect Donald Trump announced Wednesday that he has selected Daniel Driscoll to be secretary of the army. ? President Trump announces the nomination of Daniel P. Driscoll to serve as the Secretary of the Army ?? pic.twitter.com/tG4FjyI4Gg— Trump War Room (@TrumpWarRoom) December 4, 2024 Driscoll is an Iraq War veteran, having served as an officer between 2006 and 2011. He deployed to Iraq from October 2009 to July 2010, and also completed Ranger school. During his service, Driscoll earned the combat action badge, among other awards. After serving in the army, Driscoll attended Yale Law, where he befriended Vice President–elect J.D. Vance. Driscoll has since worked in venture capital and private equity and as a senior adviser to Vance. He ran for Congress in 2020, but lost the primary for North Carolina’s 11th district to Madison Cawthorn. On the same day, Trump also named Adam Boehler as his selection for the role of special presidential envoy for hostage affairs. The president-elect cited Boehler’s work as a negotiator on the Abraham Accords and in negotiations with the Taliban for his selection. ? President Trump announces that @aboehler will serve as Special Presidential Envoy for Hostage Affairs! pic.twitter.com/Ih9D0gGLBN— Trump War Room (@TrumpWarRoom) December 4, 2024 During the first Trump administration, Boehler served as the director for the Center of Medicare and Medicaid innovation between 2018 and 2019. Boehler also served as the CEO of the U.S. International Development Finance Corporation, a government institution which invests in economic development abroad, from 2019 to 2021. The post Trump Chooses Driscoll For Army Secretary appeared first on The American Conservative.