Lockheed Shares Satellite Connectivity Options

In an unusual turn of events, Lockheed Martin has released technical “payload accommodation information” for three of their satellite busses. In layperson’s terms, if you wanted to build a satellite and weren’t sure what guidelines to follow these documents may help you learn if Lockheed Martin has a platform to help you build it.

An opportunity to check out once-confidential information about satellites sounds like a perfect excuse to dig through some juicy documentation, though unfortunately this may not be the bonanza of technical tidbits the Hackaday reader is looking for. Past the slick diagrams of typical satellites in rocket fairings, the three documents in question primarily provide broad guidance. There are notes about maximum power ratings, mass and volume guidelines, available orbits, and the like. Communication bus options are varied; there aren’t 1000BASE-T Ethernet drops but multiply redundant MIL-STD-1553B might come standard, plus telemetry options for analog, serial, and other data sources up to 100 Mbps. Somewhat more usual (compared to your average PIC32 datasheet) are specifications for radiation shielding and it’s effectiveness.

In the press release EVP [Rick Ambrose] says “we’re sharing details about the kinds of payloads we can fly…” and that’s exactly what these documents give us. Physical ballpark and general guidelines about what general types of thing Lockheed has capability to build launch. Hopefully the spirit of openness will lead to the hoped-for increase in space utilization.

If you take Lockheed up on their offer of satellite development, don’t forget to drop us a tip!

[Via the Washington Post]

DIY Planetarium Built From PVC Pipes and Cardboard

When you think about DIY projects, you probably don’t consider building your own planetarium. Why would you? Building the thing is surely outside the capabilities of the individual, and even if you could figure it out, the materials would be far too expensive. There’s a limit to DIY projects, and obviously building a planetarium is on the wrong side of the line. Right?

Well, apparently not. [Gabby LeBeau] has documented the planetarium she built as her senior project, and if you’ll forgive the pun, it’s absolutely out of this world. Using readily available parts and the help of family and friends, she built a fully functional planetarium big enough to seat the Physics Department. No word on what grade she got, but it’s a safe bet she screwed the curve up for the rest of the class.

After two months of research and a couple of smaller proof of concept builds, she was able to find a business who graciously allowed her to construct the full scale planetarium in their warehouse. The frame is made of PVC pipes held together with zip ties. The big advantage to using the PVC pipes (beyond being cheap and easy to works with) is that they will automatically find a hemispherical shape when bent; saving the time and trouble it would take to create the shape with more rigid building materials.

Once the PVC frame was up, white cardboard panels were cut to shape and attached to the inside. The panels were lined up as closely as possible, but gaps were covered with white tape so the fit didn’t need to be perfect. When the dome was finished, it was lifted and placed on metal trusses to get some room underneath, and finally covered with a black tarp and stage curtain to block out all light.

Of course, she didn’t go through all this trouble to just stick some glow in the dark stars on the inside of this thing. The image from a standard projector is directed at a flat mirror, which then bounces off of a convex mirror. Driving the projector is a laptop running Stellarium. While there were some imperfections she couldn’t get polished or cleaned off of the mirrors, the end result was still very impressive.

Unfortunately, you can’t really do a planetarium justice with a camera, so we aren’t able to see what the final image looked like. But judging by the slack-jawed faces of those who are pictured inside of it, we’re going to go out on a limb and say it was awesome.

We might suggest trying to quiet down the projector or adding some lasers to the mix, but overall this is a truly exceptional project, and we’re jealous of everyone who got to experience it first hand.

Katherine Johnson: Computer To The Stars

In 1962, John Glenn sat in his capsule waiting for his rocket engines to light-up and lift him to space. But first, he insisted that Katherine Johnson double-check the electronic computer’s trajectory calculations. While that’s the dramatic version of events given in the recent movie, Hidden Figures, the reality isn’t very far off. Glenn wasn’t sitting on the launchpad at the time, but during the weeks prior to launch, he did insist that Johnson double-check the computer’s calculations.

So who is this woman who played an important but largely unknown part of such a well-known historical event? During her long life, she was a wife, a mother, an African-American, a teacher, and a human computer, a term rarely used these days. Her calculations played a part in much of early spaceflight and in 2015, she was awarded the Presidential Medal of Freedom by President Obama. She also has a building named after her at the Langley Research Center in Hampton, Virginia.

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SpaceX Joins in the Long History of Catching Stuff from Space

On February 22nd, a Falcon 9 rocket lifted off from Vandenberg Air Force Base in California and successfully delivered into orbit an Earth-observation satellite operated by the Spanish company Hisdesat. Compared to the media coverage received by the launch of the Tesla-laden Falcon Heavy earlier in the month, this mission got very little attention. But that’s hardly surprising. With respect to Hisdesat, the payload this time around was not terribly exciting, and even the normally dramatic landing of the Falcon 9’s first stage was skipped in favor of simply allowing the booster to crash into the ocean.

As far as SpaceX launches go, this one was about as low-key as they come. It wouldn’t be a surprise if this is the first time some readers are even hearing about it. But while it didn’t invoke the same media circus as the images of a spacesuit-wearing mannequin traveling into deep space, there was still a historic “first” performed during this mission.

In an effort to increase the re-usability of the Falcon 9 booster, SpaceX attempted to catch the payload fairing (essentially a large protective nose cone) with a huge net as it fell from space. The most interesting thing about this new chapter in the quest for a fully reusable rocket system is that while SpaceX is generally considered to be pioneers in the world of bringing hardware back from space, this particular trick dates all the way back to the 1960’s.

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Vera Rubin: Shedding Light on Dark Matter

Vera sat hunched in the alcove at Kitt Peak observatory, poring over punch cards. The data was the same as it had been at Lowell, at Palomar, and every other telescope she’d peered through in her feverish race to collect the orbital velocities of stars in Andromeda. Although the data was perfectly clear, the problem it posed was puzzling. If the stars at the edges of spiral galaxy were moving as fast as the ones in the center, but the pull of gravity was weaker, how did they keep from flying off? The only possible answer was that Andromeda contained some kind of unseen matter and this invisible stuff was keeping the galaxy together.

Though the idea seemed radical, it wasn’t an entirely new one. In 1933, Swiss astronomer Fritz Zwicky made an amazing discovery that was bound to bring him fame and fortune. While trying to calculate the total mass of the galaxies that make up the Coma Cluster, he found that the mass calculation based on galaxy speed was about ten times higher than the one based on total light output. With this data as proof, he proposed that much of the universe is made of something undetectable, but undeniably real. He dubbed it Dunkle Materie: Dark Matter.

But Zwicky was known to regularly bad mouth his colleagues and other astronomers in general. As a result, his wild theory was poorly received and subsequently shelved until the 1970s, when astronomer Vera Rubin made the same discovery using a high-powered spectrograph. Her findings seemed to provide solid evidence of the controversial theory Zwicky had offered forty years earlier.

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Debunking Moon Landing Denial with an Arduino and Science

It’s sad that nearly half a century after the achievements of the Apollo program we’re still arguing with a certain subset of people who insist it never happened. Poring through the historical record looking for evidence that proves the missions couldn’t possibly have occurred has become a sad little cottage industry, and debunking the deniers is a distasteful but necessary ongoing effort.

One particularly desperate denier theory holds that fully spacesuited astronauts could never have exited the tiny hatch of the Lunar Excursion Module (LEM). [AstronomyLive] fought back at this tendentious claim in a clever way — with a DIY LIDAR scanner to measure Apollo artifacts in museums. The hardware is straightforward, with a Garmin LIDAR-Lite V3 scanner mounted on a couple of servos to make a quick pan-tilt head. The rig has a decidedly compliant look to it, with the sensor flopping around a bit as the servos move. But for the purpose, it seems perfectly fine.

[AstronomyLive] took the scanner to two separate museum exhibits, one to scan a LEM hatch and one to scan the suit Gene Cernan, the last man to stand on the Moon so far, wore while training for Apollo 17. With the LEM flying from the rafters, the scanner was somewhat stretching its abilities, so the point clouds he captured were a little on the low-res side. But in the end, a virtual Cernan was able to transition through the virtual LEM hatch, as expected.

Sadly, such evidence will only ever be convincing to those who need no convincing; the willfully ignorant will always find ways to justify their position. So let’s just celebrate the achievements of Apollo.

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Predicting Starman’s Return To Earth

There’s a Starman, waiting in the sky. He’d like to come and meet us, but he’ll have to wait several million years until the Yarkovsky effect brings him around to Earth again.

In case you’ve been living under a rock for the past few weeks, SpaceX recently launched a car into space. This caused much consternation and hand-wringing, but we got some really cool pictures of side boosters landing simultaneously. The test launch for the Falcon Heavy successfully lobbed a Tesla Roadster into deep space with an orbit extending out into the asteroid belt. During the launch coverage, SpaceX said the car would orbit for Billions of years. This might not be true; a recent analysis of the random walk of cars revealed a significant probability of hitting Earth or Venus over the next Million years.

The analysis of the Tesla Roadster relies on the ephemerides provided by JPL’s Horizons database (2018-017A), and predicts the orbit over several hundred years. In the short term — a thousand years or so — there is little chance of a collision with anything. In 2091, however, the Tesla will find itself approaching Earth, and after that, the predicted orbits change drastically. As an aside, we should totally bring the Tesla back in 2091.

Even though the Tesla Roadster, its payload adapter, and the booster are inert objects floating in space right now, that doesn’t mean there aren’t forces acting on it. For small objects orbiting near the sun, the Yarkovsky effect is a huge influence on the orbit when measured on a timescale of millennia. In short, the Yarkovsky effect is a consequence of a spinning object being heated by the sun. As an object (a Tesla, or an asteroid) rotates, the side facing the sun heats up. As this side faces away from the sun, this heat is radiated out, imparting a tiny, tiny force. This force, over a period of millions of years, can send the Tesla into resonances with other planets, eventually sending it crashing into Earth, Venus, or the Sun.

The authors of this paper find there is a 6% chance the Tesla will collide with Earth and a 2.5% chance it will collide with Venus in the next one Million years. In three Million years, the probability of a collision with Earth is 11%. These are, according to the authors, extremely preliminary calculations and more observations are needed. If the Tesla were to hit the Earth, it’s doubtful whatever species populates the planet would notice; the mass of the Tesla is only 1250 Kg, and Earth flies through meteoroids weighing that much very frequently.