For those who grew up watching the endless coverage of the Apollo program in the 60s and 70s, the sight of OV-102, better known as the Space Shuttle Columbia, perched on pad 39A at the Kennedy Space Center was somewhat disconcerting. Compared to the sleek lines of a Saturn V rocket, the spacecraft on display on April 12, 1981, seemed an ungainly beast. It looked like an airplane that had been tacked onto a grain silo, with a couple of roman candles attached to it for good measure. Everything about it seemed the opposite of what we’d come to expect from spaceflight, but as the seconds ticked away to liftoff 40 years ago this day, we still had hope that this strange contraption wouldn’t disappoint.
At first, as the main engines ignited, it seemed that Columbia would indeed disappoint. The liquid hydrogen exhaust plume seemed anemic, at least compared to the gout of incandescent kerosene that had belched out from every rocket I’d ever seen launched. But then those magnificent — and as it later turned out, deadly dangerous — solid rocket boosters came to life, and Columbia fairly leaped off the launchpad. Americans were on their way to space again after a six-year absence, and I remember cheering astronauts John Young and Bob Crippen on as I watched the coverage with my dad that early Sunday morning.
A crewed mission to the International Space Station that was set to depart from Kennedy Space Center on Halloween has been pushed back at least several weeks as NASA and SpaceX investigate an issue with the company’s Merlin rocket engine. But the problem in question wasn’t actually discovered on the booster that’s slated to carry the four new crew members up to the orbiting outpost. This story starts back on October 2nd, when the computer aboard a Falcon 9 set to carry a next-generation GPS III satellite into orbit for the US Space Force shut down the engines with just two seconds to go before liftoff.
The fact that SpaceX and NASA have decided to push back the launch of a different Falcon 9 is a clear indication that the issue isn’t limited to just one specific booster, and must be a problem with the design or construction of the Merlin engine itself. While both entities have been relatively tight lipped about the current situation, a Tweet from CEO Elon Musk made just hours after the GPS III abort hinted the problem was with the engine’s gas generator:
As we’ve discussed previously, the Merlin is what’s known as an “open cycle” rocket engine. In this classical design, which dates back to the German V-2 of WWII, the exhaust from what’s essentially a smaller and less efficient rocket engine is used to spin a turbine and generate the power required to pump the propellants into the main combustion chamber. Higher than expected pressure in the gas generator could lead to a catastrophic failure of the turbine it drives, so it’s no surprise that the Falcon 9’s onboard systems determined an abort was in order.
Grounding an entire fleet of rockets because a potentially serious fault has been discovered in one of them is a rational precaution, and has been done many times before. Engineers need time to investigate the issue and determine if changes must be made on the rest of the vehicles before they can safely return to flight. But that’s where things get interesting in this case.
SpaceX hasn’t grounded their entire fleet of Falcon 9 rockets. In fact, the company has flown several of them since the October 2nd launch abort. So why are only some of these boosters stuck in their hangers, while others are continuing to fly their scheduled missions?
Orbiting over our heads right now are two human beings who flew to the International Space Station in a SpaceX Crew Dragon vehicle on top of a Falcon 9. The majority of coverage focused on the years since human spaceflight last launched from Florida, but [Eric Berger] at Ars Technica reminds us it also makes for a grand ten-year celebration of the SpaceX workhorse rocket by sharing some stories from its early days.
Falcon 9 is a huge presence in the global space launch industry today, but ten years ago the future of a young aerospace company was far from certain. The recent uneventful launch is the result of many lessons learned in those ad-hoc days. Some early Falcon 9 flights were successful because the team decided some very unconventional hacks were worth the risk that paid off. A bit of water intrusion? Dry it out with a blow dryer and seal it back up. Small tear in a rocket nozzle? Send in someone to trim a few inches with shears (while the rocket was standing vertical on the launchpad).
Industry veterans appalled at “a cowboy attitude” pounced on every SpaceX failure with “I told you so.” But the disregard for convention is intentional, documented in many places like this old Wired piece from 2012. Existing enshrined aerospace conventions meant the “how” was preserved but the “why” was reduced to “we’ve always done it this way” rarely re-evaluated in light of advancements. Plus the risk-averse industry preferred staying with flight-proven designs, setting up a Catch-22 blocking innovation. SpaceX decided to go a different way, rapidly evolving the Falcon 9 and launching at a high cadence. Learning from all the failures along the way gave them their own set of “why” to back up their “how” growing far beyond blow dryers and metal shears. We’re happy to see the fail-learn-improve cycle at the heart of so many hacker projects have proven effective to send two astronauts to the space station and likely beyond.
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.
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.
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.
After a decade in development, the Boeing CST-100 “Starliner” lifted off from pad SLC-41 at the Cape Canaveral Air Force Station a little before dawn this morning on its first ever flight. Officially referred to as the Boeing Orbital Flight Test (Boe-OFT), this uncrewed mission was intended to verify the spacecraft’s ability to navigate in orbit and safely return to Earth. It was also planned to be a rehearsal of the autonomous rendezvous and docking procedures that will ultimately be used to deliver astronauts to the International Space Station; a capability NASA has lacked since the 2011 retirement of the Space Shuttle.
Unfortunately, some of those goals are now unobtainable. Due to a failure that occurred just 30 minutes into the flight, the CST-100 is now unable to reach the ISS. While the craft remains fully functional and in a stable orbit, Boeing and NASA have agreed that under the circumstances the planned eight day mission should be cut short. While there’s still some hope that the CST-100 will have the opportunity to demonstrate its orbital maneuverability during the now truncated flight, the primary focus has switched to the deorbit and landing procedures which have tentatively been moved up to the morning of December 22nd.
While official statements from all involved parties have remained predictably positive, the situation is a crushing blow to both Boeing and NASA. Just days after announcing that production of their troubled 737 MAX airliner would be suspended, the last thing that Boeing needed right now was another high-profile failure. For NASA, it’s yet another in a long line of setbacks that have made some question if private industry is really up to the task of ferrying humans to space. This isn’t the first time a CST-100 has faltered during a test, and back in August, a SpaceX Crew Dragon was obliterated while its advanced launch escape system was being evaluated.
We likely won’t have all the answers until the Starliner touches down at the White Sands Missile Range and Boeing engineers can get aboard, but ground controllers have already started piecing together an idea of what happened during those first critical moments of the flight. The big question now is, will NASA require Boeing to perform a second Orbital Flight Test before certifying the CST-100 to carry a human crew?
Let’s take a look at what happened during this morning’s launch.
It’s 2100 AD, and hackers and normals live together in mile-long habitats in the Earth-Moon system. The habitat is spun up so that the gravity inside is that of Earth, and for exercise, the normals cycle around on bike paths. But the hackers do their cycling outside, in the vacuum of space.
How so? With ion thrusters, rocketing out xenon gas as the propellant. And the source of power? Ultimately that’s the hackers’ legs, pedaling away at a drive system that turns two large Wimshurst machines.
Those Wimshurst machines then produce the high voltage needed for the thruster’s ionization as well as the charge flow. They’re also what gives the space bike it’s distinctly bicycle-like appearance. And based on the calculations below, this may someday work!