Astra’s Frugal Design Leads To Latest Unusual Failure

February 23, 2022 by Tom Nardi 36 Comments

We’ve all heard it said, and it bears repeating: getting to space is hard. But it actually gets even harder the smaller your booster is. That’s because the structure, engines, avionics, and useful payload of a rocket only make up a tiny portion of its liftoff mass, while the rest is dedicated to the propellant it must expend to reach orbital velocity. That’s why a Falcon 9 tipping the scales at 549,054 kilograms (1,207,920 pounds) can only loft a payload of 22,800 kg (50,265 lb) — roughly 4% of its takeoff weight.

As you might imagine, there’s a lower limit where there simply isn’t enough mass in the equation for the hardware necessary to build a fully functional rocket. But where is that limit? That’s precisely what aerospace newcomer Astra is trying to find out. Their Rocket 3 is among the smallest orbital boosters to ever fly, closer in size and mass to the German V2 of World War II than the towering vehicles being built by SpaceX or Blue Origin. Even the Rocket Lab Electron, itself an exceptionally svelte rocket, is considerably larger.

The reason they’re trying to build such a small rocket is of course very simple: smaller means cheaper. Assuming you’ve got a payload light and compact enough to fit on their launcher, Astra says they can put it into orbit for roughly $2.5 million USD; less than half the cost of a dedicated flight aboard Rocket Lab’s Electron, and competitive with SpaceX’s “rideshare” program. Such a low ticket price would have been unfathomable a decade ago, and promises to shake up an already highly competitive commercial launch market. But naturally, Astra has to get the thing flying reliably before we can celebrate this new spaceflight milestone.

Their latest mission ended in a total loss of the vehicle and payload when the upper stage tumbled out of control roughly three minutes after an otherwise perfect liftoff from Cape Canaveral Space Force Station in Florida. Such issues aren’t uncommon for a new orbital booster, and few rockets in history have entered regular service without a lost payload or two on the books. But this failure, broadcast live over the Internet, was something quite unusual: because of the unconventional design of Astra’s diminutive rocket, the upper stage appeared to get stuck inside the booster after the payload fairing failed to open fully.

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How Big Is The Moon? Figure It Out Yourself

February 22, 2022 by Al Williams 4 Comments

We have to confess that we occasionally send friends a link to “let me Google that for you” when they ask us something that they could have easily found online. Naturally, if someone asked us how big the moon is, we’d ask Google or another search engine. But not [Prof Matt Strassler]. He’d tell you to figure it out yourself and he would then show you how to do it.

This isn’t a new question. People have been wondering about the moon since the dawn of human civilization. The ancient Greeks not only asked the question, but they worked out a pretty good answer. They knew approximately how big the Earth was and they knew the moon was far away because it is seen over a very wide area. They also knew the sun was even further away because the moon sometimes blocks the sun’s light in an eclipse. Using complex geometry and proto-trigonometry they were able to work out an approximate size of the moon. [Matt’s] method is similar but easier and relies on the moon occluding distant stars and planets.

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Put A Little Piece Of The James Webb On Your Wall

February 16, 2022 by Tom Nardi 59 Comments

The James Webb Space Telescope (JWST) has become something of a celebrity here on Earth, and rightfully so. After decades of development, the $10 billion deep space observatory promises to peel back the mysteries of the universe in a way that simply hasn’t been possible until now. Plus, let’s be honest, the thing just looks ridiculously cool.

So is it really such a surprise that folks would want a piece of this marvel hanging up in their wall? No, it’s not the real thing, but this rendition of the JWST’s primary mirror created by [James Kiefer] and [Ryan Kramer] certainly gets the point across.

A CNC router was used to cut the outside shape from a piece of 1/2 inch MDF, as well as put 1 mm deep pockets in the face to accept the hexagonal golden acrylic mirrors. We originally thought the mirrors were also custom made, but somewhat surprisingly, gold-tinted hex mirrors are apparently popular enough in the home decor scene that they’re readily available online for cheap. A quick check with ~~everyone’s favorite~~ a large online bookseller turned global superpower shows them selling for as little as $0.50 a piece.

With a coat of black paint on the MDF, the finished piece really does look the part. We imagine it’s fairly heavy though, and wonder how it would have worked out if the back panel was cut from a piece of thick foam board instead.

Of course this isn’t a terribly difficult design to recreate if you had to, but we still appreciate that the duo has decided to release both the Fusion 360 project file and the exported STL to the public. It seems only right that this symbol for science and discovery should be made available to as many people as possible.

After a dramatic launch on Christmas Day and a perilous flight through deep space, the JWST has performed impeccably. Even though we’re still a several months away from finally seeing what this high-tech telescope is capable of, it’s already managed to ignite the imaginations of people all over the globe.

Martian Wheel Control Algorithms Gain Traction

February 15, 2022 by Ryan Flowers 13 Comments

Imagine the scene: You’re puttering along in your vehicle when, at least an hour from the nearest help, one of your tires starts losing air. Not to worry! You’ve got a spare tire along with the tools and knowhow to change it. And if that fails, you can call roadside assistance. But what if your car isn’t a car, has metal wheels for which no spares are available, and the nearest help is 200 million miles away? You just might be a Jet Propulsion Laboratory Engineer on the Curiosity Mars Rover mission, who in 2017 was charged with creating a new driving algorithm designed to extend the life of the wheels.

High Performance Rock Crawler, Courtesy Spidertrax.com License: CC BY 3.0

You could say that the Curiosity Mars rover is the ultimate off-road vehicle, and as such it has to deal with conditions that are in some ways not that different from some locations here on Earth. Earth bound rock crawlers use long travel suspensions, specialized drivetrains, and locking differentials to keep the tires on the ground and prevent a loss of traction.

On Mars, sand and rocks dominate the landscape, and a rover must navigate around the worst of it. It’s inevitable that, just like a terrestrial off-roader, the Mars rovers will spin a tire now and then when a wheel loses traction. The Mars rovers also have a specialized drivetrain and long travel suspensions. They don’t employ differentials, though, so how are they to prevent a loss of traction and the damaging wheel spin that ensues? This where the aforementioned traction control algorithm comes in.

By controlling the rotation of the wheels with less traction, they can still contribute to the motion of the vehicle while avoiding rock rash. Be sure to check out the excellent article at JPL’s website for a full explanation of their methodology and the added benefits of uploading new traction control algorithms from 200 million miles away! No doubt the Perseverance Mars rover has also benefited from this research.

But why should NASA get to have all the fun? You can join them by 3d printing your own Mars rover and just maybe some Power Wheels derived traction control. What fun!

NASA Taps Lockheed To Bring Back A Piece Of Mars

February 14, 2022 by Tom Nardi 36 Comments

Since NASA’s Mariner spacecraft made the first up-close observations of Mars in 1964, humanity has lobbed a long line of orbiters, landers, and rovers towards the Red Planet. Of course, it hasn’t all been smooth sailing. History, to say nothing of the planet’s surface, is littered with Martian missions that didn’t quite make the grade. But we’ve steadily been getting better, and have even started to push the envelope of what’s possible with interplanetary robotics through ambitious craft like the Ingenuity helicopter.

Yet, after nearly 60 years of studying our frigid neighbor, all we have to show for our work boils down to so many 1s and 0s. That’s not to say the data we’ve collected, both from orbit and on the surface, hasn’t been extremely valuable. But scientists on Earth could do more with a single Martian rock than any robotic rover could ever hope to accomplish. Even still, not so much as a grain of sand has ever been returned from the planet’s dusty surface.

But if everything goes according to plan, that’s about to change. Within the next decade, NASA and the European Space Agency (ESA) hope to bring the first samples of Martian rocks, soil, and atmospheric gases back to Earth using a series of robotic vehicles. While it’s still unclear when terrestrial scientists should expect delivery of this interplanetary bounty, the first stage of the program is already well underway. The Perseverance rover has started collecting samples and storing them in special tubes for their eventual trip back to Earth. By 2028, another rover will be deployed to collect these samples and load them into a miniature rocket for their trip to space.

Launching the Mars Ascent Vehicle (MAV).

Just last week NASA decided to award the nearly $200 million contract to build that rocket, known officially as the Mars Ascent Vehicle (MAV), to aerospace giant Lockheed Martin. The MAV will not only make history as the first rocket to lift off from a celestial body other than the Earth, but it’s arguably the most critical component of the sample return mission; as any failure during launch will mean the irrevocable loss of all the samples painstakingly recovered by Perseverance over the previous seven years.

To say this mission constitutes a considerable technical challenge would be an understatement. Not only has humanity never flown a rocket on another planet, but we’ve never even attempted it. No matter what the outcome, once the MAV points its nose to the sky and lights its engines, history is going to be made. But while it will be the first vehicle to make the attempt, engineers and scientists have been floating plans for a potential Martian sample return mission for decades. Continue reading “NASA Taps Lockheed To Bring Back A Piece Of Mars” →

Sergiy Nesterenko giving his Remoticon 2021 talk

Remoticon 2021 // Sergiy Nesterenko Keeps Hardware Running Through Lightning And Cosmic Rays

February 10, 2022 by Robin Kearey 1 Comment

Getting to space is hard enough. You have to go up a few hundred miles, then go sideways really fast to enter orbit. But getting something into space is one thing: keeping a delicate instrument working as it travels there is quite another. In his talk at Remoticon 2021, [Sergiy Nesterenko], former Radiation Effects Engineer at SpaceX, walks us through all the things that can destroy your sensitive electronics on the way up.

The trouble already starts way before liftoff. Due to an accident of geography, several launch sites are located in areas prone to severe thunderstorms: not the ideal location to put a 300-foot long metal tube upright and leave it standing for a day. Other hazards near the launch pad include wayward wildlife and salty spray from the ocean.

Those dangers are gone once you’re in space, but then suddenly heat becomes a problem: if your spacecraft is sitting in full sunlight, it will quickly heat up to 135 °C, while the parts in the shade cool off to -150 °C. A simple solution is to spin your craft along its axis to ensure an even heat load on all sides, similar to the way you rotate sausages on your barbecue.

But one of the most challenging problems facing electronics in space is radiation. [Sergiy] explains in detail the various types of radiation that a spacecraft might encounter: charged particles in the Van Allen belts, cosmic rays once you get away from Low Earth orbit, and a variety of ionized junk ejected from the Sun every now and then. The easiest way to reduce the radiation load on your electronics is simply to stay near Earth and take cover within its magnetic field.

For interplanetary spacecraft there’s no escaping the onslaught, and the only to survive is to make your electronics “rad-hard”. Shielding is generally not an option because of weight constraints, so engineers make use of components that have been tested in radiation chambers to ensure they will not suddenly short-circuit. Adding redundant circuits as well as self-monitoring features like watchdog timers also helps to make flight computers more robust.

[Sergiy]’s talk is full of interesting anecdotes that will delight the inner astronaut in all of us. Ever imagined a bat trying to hitch a ride on a Space Shuttle? As it turns out, one aspiring space bat did just that. And while designing space-qualified electronics is not something most of us do every day, [Sergiy]’s experiences provide plenty of tips for more down-to-earth problems. After all, salt and moisture will eat away cables on your bicycle just as they do on a moon rocket.

Be sure to also check out the links embedded in the talk’s slides for lots of great background information.

Continue reading “Remoticon 2021 // Sergiy Nesterenko Keeps Hardware Running Through Lightning And Cosmic Rays” →

Working Model Reveals Amazing Engineering Of Webb’s Mirror Actuators

February 8, 2022 by Dan Maloney 30 Comments

We end up covering a lot of space topics here on Hackaday, not because we’re huge space nerds — spoiler alert: we are — but because when you’ve got an effectively unlimited budget and a remit to make something that cannot fail, awe-inspiring engineering is often the result. The mirror actuators on the James Webb Space Telescope are a perfect example of this extreme engineering, and to understand how they work a little better, [Zachary Tong] built a working model of these amazing machines.

The main mirror of the JWST is made of 18 separate hexagonal sections, the position of each which must be finely tuned to make a perfect reflector. Each mirror has seven actuators that move it through seven degrees of freedom — the usual six that a Stewart platform mechanism provides, plus the ability to deform the mirror’s curvature slightly. [Zach]’s model actuator is reverse-engineered from public information (PDF) made available by the mirror contractor, Ball Aerospace. While the OEM part is made from the usual space-rated alloys and materials, the model is 3D printed and powered by a cheap stepper motor.

That simplicity belies the ingenious mechanism revealed by the model. The actuators allow for both coarse and fine adjustments over a wide range of travel. A clever tumbler mechanism means that only one motor is needed for both fine and coarse adjustments, and a flexure mechanism is used to make the fine adjustments even finer — a step size of only 8 nanometers!

Hats off to [Zach] for digging into this for us, and for making all his files available in case you want to print your own. You may not be building a space observatory anytime soon, but there’s plenty about these mechanisms that can inform your designs.

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