The Apollo Digital Ranging System: More Than Meets The Eye

If you haven’t seen [Ken Shirriff]’s teardowns and reverse engineering expeditions, then you’re in for a treat. His explanation and demonstration of the Apollo digital ranging system is a fascinating read, even if vintage computing and engineering aren’t part of your normal fare.

The average Hackaday reader should be familiar with the concept of determining the distance of a faraway object by measuring how long it takes a sound or radio wave to be reflected, such as in sonar and radar. Going another step and measuring Doppler Shift – the difference in the returned signal’s frequency – will tell us the velocity of the object relative to our position. It’s so simple that an Arduino can do it. But in the days of Apollo, there was no Arduino. In fact, there were no Integrated Circuits. And Apollo missions went all the way to the moon- far too distant for relatively simple Radar measurements. Continue reading “The Apollo Digital Ranging System: More Than Meets The Eye”

Keep Tabs On Asteroids With Asteroid Atlas

Keeping tabs on the night sky is an enjoyable way to stay connected to the stars, and astronomy can be accessible to most people with a low entry point for DIY telescopes. For those who live in areas with too much light pollution, though, cost is not the only issue facing amateur astronomers. Luckily there are more ways to observe the night sky, like with this open source software package from [elanorlutz] which keeps tabs on all known asteroids.

The software is largely based on Python and uses a number of databases from NASA to allow anyone with a computer to explore various maps of the solar system and the planetary and non-planetary bodies within it. Various trajectories can be calculated, and paths of other solar system bodies can be shown with respect to an observer in various locations. Once the calculations are made in Python it is able to export the images for use in whichever image manipulation software you prefer.

The code that [elanorlutz] has created is quite extensive and ready to use for anyone interested in tracking comets, trans-Neptunian objects, or even planets and moons from their own computer. We would imagine a tool like this would be handy for anyone with a telescope as well as it could predict locations of objects in the night sky with accuracy and then track them with the right hardware.

Classic Chat: Arko Takes Us Inside NASA’s Legendary JPL

Started by graduate students from the California Institute of Technology in the late 1930s, the Jet Propulsion Laboratory (JPL) was instrumental in the development of early rocket technology in the United States. After being tasked by the Army to analyze the German V2 in 1943, the JPL team expanded from focusing purely on propulsion systems to study and improve upon the myriad of technologies required for spaceflight. Officially part of NASA since December of 1958, JPL’s cutting edge research continues to be integral to the human and robotic exploration of space.

For longtime friend of Hackaday Ara “Arko” Kourchians, getting a job JPL as a Robotics Electrical Engineer was a dream come true. Which probably explains why he applied more than a dozen times before finally getting the call to join the team. He stopped by the Hack Chat back in August of 2019 to talk about what it’s like to be part of such an iconic organization, reminisce about some of his favorite projects, and reflect on the lessons he’s learned along the way.

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The Wright Stuff: First Powered Flight On Mars Is A Success

When you stop to think about the history of flight, it really is amazing that the first successful flight the Wright brothers made on a North Carolina beach to Neil Armstrong’s first steps on the Moon spanned a mere 66 years. That we were able to understand and apply the principles of aerodynamics well enough to advance from delicate wood and canvas structures to rockets powerful enough to escape from the gravity well that had trapped us for eons is a powerful testament to human ingenuity and the drive to explore.

Ingenuity has again won the day in the history of flight, this time literally as the namesake helicopter that tagged along on the Mars 2020 mission has successfully flown over the Red Planet. The flight lasted a mere 40 seconds, but proved that controlled, powered flight is possible on Mars, a planet with an atmosphere that’s as thin as the air is at 100,000 feet (30 km) above sea level on Earth. It’s an historic accomplishment, and the engineering behind it is worth a deeper look.

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A Technical (But Not Too Technical) Explanation Of Landing Perseverance Rover On Mars

There was a lot of enthusiasm surrounding Mars arrival of Perseverance rover, our latest robotic interplanetary explorer. Eager to capitalize on this excitement, NASA JPL released a lot of information to satisfy curiosity of the general public. But making that material widely accessible also meant leaving out many technical details. People who crave just a little more can head over to How NASA’s Perseverance Landed On Mars: An Aerospace Engineer Breaks It Down In Fascinating Detail published by Jalopnik.

NASA JPL’s public materials mostly explained the mission in general terms. Even parts with scientific detail were largely constrained for a target audience of students K-12. Anyone craving more details can certainly find them online, but they would quickly find themselves mired in highly technical papers written by aerospace engineers and planetary geologists for their peers. There is a gap in between those extremes, and this write-up slots neatly in that gap. Author [Brian Kirby] is our helpful aerospace engineer who compiled many technical references into a single narrative of the landing, explained at a level roughly equivalent to undergraduate level math and science courses.

We get more details on why the target landing site is both geologically interesting and technically treacherous, requiring development of new landing smarts that will undoubtedly help future explorers both robotic and human. The complex multi-step transition from orbit to surface is explained in terms of managing kinetic energy. Condensing a wide range of problems to a list of numbers that helps us understand why, for example, a parachute was necessary yet not enough to take a rover all the way to the surface.

Much of this information is known to longtime enthusiasts, but we all had to get our start somewhere. This is a good on-ramp for a new generation of space fans, and together we look forward to Perseverance running down its long and exciting to-do list. Including flying a helicopter, packing up surface samples of Mars, and seeing if we can extract usable oxygen from Martian atmosphere.

Getting Ready For Mars: The Seven Minutes Of Terror

For the past seven months, NASA’s newest Mars rover has been closing in on its final destination. As Perseverance eats up the distance and heads for the point in space that Mars will occupy on February 18, 2021, the rover has been more or less idle. Tucked safely into its aeroshell, we’ve heard little from the lonely space traveler lately, except for a single audio clip of the whirring of its cooling pumps.

Its placid journey across interplanetary space stands in marked contrast to what lies just ahead of it. Like its cousin and predecessor Curiosity, Perseverance has to successfully negotiate a gauntlet of orbital and aerodynamic challenges, and do so without any human intervention. NASA mission planners call it the Seven Minutes of Terror, since the whole process will take just over 400 seconds from the time it encounters the first wisps of the Martian atmosphere to when the rover is safely on the ground within Jezero Crater.

For that to happen, and for the two-billion-dollar mission to even have a chance at fulfilling its primary objective of searching for signs of ancient Martian life, every system on the spacecraft has to operate perfectly. It’s a complicated, high-energy ballet with high stakes, so it’s worth taking a look at the Seven Minutes of Terror, and what exactly will be happening, in detail.

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

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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