Displaying HTML Interfaces And Managing Network Nodes… In Space!

June 8, 2020 by Roger Cheng 44 Comments

The touchscreen interface aboard SpaceX Crew Dragon is just one of its many differences from past space vehicles, but those big screens make an outsized visual impact. Gone are panels filled with indicator needles in gauges, or endless rows of toggle switches. It looked much like web interaction on everyday tablets for good reason: what we see is HTML and JavaScript rendered by the same software core underlying Google’s Chrome browser. This and many other details were covered in a Reddit Ask Me Anything with members of the SpaceX software team.

Various outlets have mentioned Chromium in this context, but without answering the obvious follow-up question: how deep does Chromium go? In this AMA we learn it does not go very deep at all. Chromium is only the UI rendering engine, their fault tolerant flight software interaction is elsewhere. Components such as Chromium are isolated to help keep system behavior predictable, so a frozen tab won’t crash the capsule. Somewhat surprisingly they don’t use a specialized real-time operating system, but instead a lightly customized Linux built with PREEMPT_RT patches for better real-time behavior.

In addition to Falcon rocket and Dragon capsule, this AMA also covered software work for Starlink which offered interesting contrasts in design tradeoffs. Because there are so many satellites (and even more being launched) loss of individual spacecraft is not a mission failure. This gives them elbow room for rapid iteration, treating the constellation more like racks of servers in a datacenter instead of typical satellite operations. Where the Crew Dragon code has been frozen for several months, Starlink code is updated rapidly. Quickly enough that by the time newly launched Starlink satellites reach orbit, their code has usually fallen behind the rest of the constellation.

Finally there are a few scattered answers outside of space bound code. Their ground support displays (visible in Hawthorne mission control room) are built with LabVIEW. They also confirmed that contrary to some claims, the SpaceX ISS docking simulator isn’t actually running the same code as Crew Dragon. Ah well.

Anyone interested in what it takes to write software for space would enjoy reading through these and other details in the AMA. And since it had a convenient side effect of serving as a recruiting event, there are plenty of invitations to apply if anyone has ambitions to join the team. We certainly can’t deny the attraction of helping to write the next chapter in human spaceflight.

[Photo credit: SpaceX]

NASA’s Long-Delayed Return To Human Spaceflight

June 1, 2020 by Tom Nardi 55 Comments

With the launch of the SpaceX Demo-2 mission, the United States has achieved something it hasn’t done in nearly a decade: put a human into low Earth orbit with a domestic booster and vehicle. It was a lapse in capability that stretched on far longer than anyone inside or outside of NASA could have imagined. Through a series of delays and program cancellations, the same agency that put boot prints on the Moon and built the iconic Space Shuttle had been forced to rely on Russia to carry its astronauts into space since 2011.

NASA would still be waiting to launch its own astronauts had they relied on America’s traditional aerospace giants to get the job done. The inaugural flight of the Boeing CST-100 “Starliner” to the International Space Station in December was an embarrassing failure that came perilously close to losing the unmanned capsule. A later investigation found that sloppy software development and inconsistent testing had caused at least two major failures during the mission, which ultimately had to be cut short as the vehicle couldn’t even reach the altitude of the ISS, to say nothing of making a docking attempt. NASA and Boeing have since agreed to attempt another test of the CST-100 sometime before the end of the year, though a delay into 2021 seems almost inevitable due to the global pandemic.

But America’s slow return to human spaceflight can’t be blamed on the CST-100, or even Boeing, for that matter. Since the retirement of the Space Shuttle, NASA has been hindered by politics and indecisiveness. With a constantly evolving mandate from the White House, the agency’s human spaceflight program has struggled to make significant progress towards any one goal.

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Docking With ISS Isn’t As Easy As You Might Think

May 15, 2020 by Al Williams 48 Comments

Complexity is a funny thing. In prehistoric times, a caveman might float across a lake on a log. That’s simple. But as you add a rudder, a sail, or even a motor, it gets more and more complex. But if you add enough complexity — a GPS and an autopilot, for example, it becomes simple again. The SpaceX Dragon capsule actually docks itself to the ISS. However, the crew on the station can take over manually if they need to. What would that be like? Try the simulation and find out. If you don’t make it on the first, try, [Scott Manley’s] video below might help you out.

This isn’t a flashy Star Wars-style simulator. Think more 2001. Movement is slow and it is easy to get out of control. The user interface is decidedly modern compared to the old Apollo era

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SpaceX Offers NASA A Custom Moon Freighter

April 15, 2020 by Tom Nardi 58 Comments

Under the current Administration, NASA has been tasked with returning American astronauts to the Moon as quickly as possible. The Artemis program would launch a crewed mission to our nearest celestial neighbor as soon as 2024, and establish a system for sustainable exploration and habitation by 2028. It’s an extremely aggressive timeline, to put it mildly.

To have any chance of meeting these goals, NASA will have to enlist the help of not only its international partners, but private industry. There simply isn’t enough time for the agency to design, build, and test all of the hardware that will eventually be required for any sort of sustained presence on or around the Moon. By awarding a series of contracts, NASA plans to offload some of the logistical components of the Artemis program to qualified companies and agencies.

For anyone who’s been following the New Space race these last few years, it should come as no surprise to hear that SpaceX has already been awarded one of these lucrative logistics contracts. They’ve been selected as the first commercial provider for cargo deliveries to Gateway, a small space station that NASA intendeds to operate in lunar orbit. Considering SpaceX already has a contract to resupply the International Space Station, they were the ideal candidate to offer similar services for a future lunar outpost.

But that certainly doesn’t mean it will be easy. The so-called “Gateway Logistics Services” contract stipulates that providers must be able to deliver at least 3,400 kilograms (7,500 pounds) of pressurized cargo and 1,000 kilograms (2,200 pounds) of unpressurized cargo to lunar orbit. That’s beyond the capabilities of SpaceX’s Dragon spacecraft, which was only designed to service low Earth orbit.

To complete this new mission, the company is proposing a new vehicle they’re calling the Dragon XL that would ride to orbit on the Falcon Heavy booster. But even for this New Space darling, there’s not a lot of time to design, test, and build a brand-new spacecraft. To get the Dragon XL flying as quickly as possible, SpaceX is going to need to strip the craft down to the bare minimum.

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A SpaceX Falcon 9 Will Blow Up Very Soon, And That’s OK

January 16, 2020 by Tom Nardi 27 Comments

They say you can’t make an omelette without breaking a few eggs, and there are few fields where this idiom is better exemplified than rocketry. It’s a forgone conclusion that when you develop a new booster, at least a few test articles are going to be destroyed in the process. In fact, some argue that a program that doesn’t push the hardware to the breaking point is a program that’s not testing aggressively enough.

Which is why, assuming everything goes according to plan, SpaceX will be obliterating one of their Falcon 9 boosters a little after 8:00 AM EST on Saturday morning. The event will be broadcast live via the Internet, and thanks to the roughly 70% propellant load it will be carrying at the moment of its destruction, it should prove to be quite a show.

This might seem like an odd way to spend $62 million, but for SpaceX, it’s worth it to know that the Crew Dragon Launch Abort System (LES) will work under actual flight conditions. The LES has already been successfully tested once, but that was on the ground and from a standstill. It allowed engineers to see how the system would behave should an abort occur while the rocket was still on the pad, but as the loss of the Soyuz MS-10 dramatically demonstrated, astronauts may need to make a timely exit from a rocket that’s already well on the way to space.

In an actual emergency, the crewed spacecraft will very likely be speeding away from a violent explosion and rapidly expanding cloud of shrapnel. The complete destruction of the Falcon 9 that will be carrying the Crew Dragon during Saturday’s test will serve to create the same sort of conditions the spacecraft will need to survive if the LES has any hope of bringing the crew home safely. So even if there was some way to prevent the booster from breaking up during the test, it’s more useful from an engineering standpoint to destroy it.

Of course, that only explains why the Falcon 9 will be destroyed during this test. But exactly how this properly functioning booster will find itself being ripped to pieces high over the Atlantic Ocean in a matter of seconds is an equally interesting question.

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SpaceX Clips Dragon’s Wings After Investigation

August 5, 2019 by Tom Nardi 120 Comments

When the SpaceX Dragon spacecraft reached orbit for the first time in 2010, it was a historic achievement. But to qualify for NASA’s Commercial Orbital Transportation Services (COTS) program, the capsule also needed to demonstrate that it could return safely to Earth. Its predecessor, the Space Shuttle, had wings that let it glide home and land like a plane. But in returning to the classic capsule design of earlier spacecraft, SpaceX was forced to rely on a technique not used by American spacecraft since the 1970s: parachutes and an ocean splashdown.

The Dragon’s descent under parachute, splashdown, and subsequent successful recovery paved the way for SpaceX to begin a series of resupply missions to the International Space Station that continue to this day. But not everyone at SpaceX was satisfied with their 21st century spacecraft having to perform such an anachronistic landing. At a post-mission press conference, CEO Elon Musk told those in attendance that eventually the Dragon would be able to make a pinpoint touchdown using thrusters and deployable landing gear:

The architecture that you observed today is obviously similar to what was employed in the Apollo era, but the next generation Dragon, the Crew Dragon, we’re actually going to be aiming for a propulsive landing with gear. We’ll still have the parachutes as a backup, but it’s going to be a precision landing, you could literally land on something the size of a helipad propulsively with gear, refuel, and take off again.

But just shy of a decade later, the violent explosion of the first space worthy Crew Dragon has become the final nail in the coffin for Elon’s dream of manned space capsules landing like helicopters. In truth, the future of this particular capability was already looking quite dim given NASA’s preference for a more pragmatic approach to returning their astronauts from space. But Crew Dragon design changes slated to be implemented in light of findings made during the accident report will all but completely remove the possibility of Dragon ever performing a propulsive landing.

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See How Paper Maché Sculptor Uses Cloth For Tricky Spots

December 28, 2018 by Donald Papp 3 Comments

When is paper maché not paper maché? When it is cloth, of course. [Dan Reeder] has been putting his own spin on paper maché art since the 70s and demonstrates the technique of using cloth for tricky spots in his outstanding sculpture of an Ice Dragon. Thin strips of cloth are used just as paper would be, but give a much different structure and grant natural-looking folds to spots like eyelids, nostrils, and lips.

[Dan] feels that paper maché is an under-utilized and under-rated medium, and he puts out some stunning work on his blog as well as his YouTube channel. What’s great to see are his frank descriptions and explanations of what does and doesn’t work, and he’s not afraid to try new things and explore different ways to approach problems.

Enterprising hackers may not pick paper maché as their first choice to create creating custom enclosures, but it can be done and the accessibility and ease of use of the medium are certainly undeniable. One never knows when a tool or technique may come in handy.