Virgin Galactic’s Long Road To Commercial Spaceflight

June 1, 2021 by Tom Nardi 24 Comments

To hear founder Richard Branson tell it, the first operational flight of Virgin Galactic’s SpaceShipTwo has been 18 months out since at least 2008. But a series of delays, technical glitches, and several tragic accidents have continually pushed the date back to the point that many have wondered if it will ever happen at all. The company’s glacial pace has only been made more obvious when compared with their rivals in the commercial spaceflight field such as SpaceX and Blue Origin, which have made incredible leaps in bounds in the last decade.

Richard Branson watching *Unity’s* test flight.

But now, at long last, it seems like Branson’s suborbital spaceplane might finally start generating some income for the fledgling company. Their recent successful test flight, while technically the company’s third to reach space, represents an important milestone on the road to commercial service. Not only did it prove that changes made to Virgin Space Ship (VSS) Unity in response to issues identified during last year’s aborted flight were successful, but it was the first full duration mission to fly from Spaceport America, the company’s new operational base in New Mexico.

The data collected from this flight, which took pilots Frederick “CJ” Sturckow and Dave Mackay to an altitude of 89.23 kilometers (55.45 miles), will be thoroughly reviewed by the Federal Aviation Administration as part of the process to get the vehicle licensed for commercial service. The next flight will have four Virgin Galactic employees join the pilots, to test the craft’s performance when loaded with passengers. Finally, Branson himself will ride to the edge of space on Unity’s final test flight as a public demonstration of his faith in the vehicle.

If all goes according to plan, the whole process should be wrapped up before the end of the year. At that point, between the government contracts Virgin Galactic has secured for testing equipment and training astronauts in a weightless environment, and the backlog of more than 600 paying passengers, the company should be bringing in millions of dollars in revenue with each flight.

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Space Propulsion: Separating Fact From Science Fiction

April 19, 2021 by Maya Posch 102 Comments

An unfortunate property of science-fiction is that it is, tragically, fiction. Instead of soaring between the stars and countless galaxies out there, we find ourselves hitherto confined to this planet we call Earth. Only a handful of human beings have ever made it as far as the Earth’s solitary moon, and just two of our unmanned probes have made it out of the Earth’s solar system after many decades of travel. It’s enough to make one despair that we’ll never get anywhere near the fantastic future that was seemingly promised to us by science-fiction.

Yet perhaps not all hope is lost. Over the past decades, we have improved our chemical rockets, are experimenting with various types of nuclear rockets, and ion thrusters are a common feature on modern satellites as well as for missions within the solar system. And even if the hype around the EMDrive vanished as quickly as it had appeared, the Alcubierre faster-than-light drive is still a tantalizing possibility after many years of refinements.

Even as physics conspires against our desire for a life among the stars, what do our current chances look like? Let’s have a look at the propulsion methods which we have today, and what we can look forward to with varying degrees of certainty.

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3D Printed Vortex Cooled Rocket Needs To Stop Leaking

March 23, 2021 by Lewin Day 27 Comments

Rocket engines are known for one thing above all else, and that’s getting hot. It’s this very property that makes them such a challenge to build and run from a materials engineering standpoint. It’s hard enough to build one with advanced metal alloys, but [Integza] presses on with trying to make one on a 3D printer. Progress is being made, but success remains elusive. (Video, embedded below.)

To try and mitigate the thermal effects of burning propellants in his engine design, [Integza] looked to vortex cooling. This is where oxygen is swirled around the outer edge of the combustion chamber in a vortex, acting as a buffer layer between the burning fuel and the chamber walls. With 3D printed chamber components, keeping temperatures as low as possible is key, after all. Unfortunately, despite using a special ceramic-laden resin for printing and lathering the rocket components in various refractory materials, it wasn’t possible to stop the chambers leaking. Solid combustion was possible for a few seconds at a time, but eventually each motor tested turned into a ball of flames as the walls broke down.

Thankfully, nobody was hurt in testing, and [Integza] has a clear idea of the problems that need to be fixed in the next iteration. We’ve featured other vortex cooled rockets before – the theory is sound. As always, the devil is in the implementation.

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It Isn’t Rocket Science — Wait, Maybe It Is

January 13, 2021 by Al Williams 22 Comments

We don’t know why, but for some reason, the more dangerous something is, the more hacker appeal it seems to have. We like to deal with high temperatures, high voltages, dangerous chemicals, and powerful lasers. So [Tech Ingredient’s] recent video about homemade rocket motors certainly caught our attention. You may need a little commitment, though. The first video (yes, there isn’t just one) is over an hour long.

Turns out, [Tech] doesn’t actually want to use the rockets for propulsion. He needed a source of highly-ionized high-velocity plasma to try to get more power from his magnetohydrodynamic project. Whatever you want to use it for, these are serious-sized motors. [Tech] claims that his design is both powerful and easy to build. He also has a “secret” rocket fuel that he shares. What is it? We won’t spoil the video for you, but it is a sweet surprise.

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Engine Trouble Delays SpaceX’s Return To The ISS

October 27, 2020 by Tom Nardi 20 Comments

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?

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Masten Moon Rocket Has Landing Pad, Will Travel

May 20, 2020 by Tom Nardi 65 Comments

Because of the architecture used for the Apollo missions, extended stays on the surface of the Moon weren’t possible. The spartan Lunar Module simply wasn’t large enough to support excursions of more than a few days in length, and even that would be pushing the edge of the envelope. But then the Apollo program was never intended to be anything more than a proof of concept, to demonstrate that humans could make a controlled landing on the Moon and return to Earth safely. It was always assumed that more detailed explorations would happen on later missions with more advanced equipment and spacecraft.

Now NASA hopes that’s finally going to happen in the 2020s as part of its Artemis program. These missions won’t just be sightseeing trips, the agency says they’re returning with the goal of building a sustainable infrastructure on and around our nearest celestial neighbor. With a space station in lunar orbit and a permanent outpost on the surface, personnel could be regularly shuttled between the Earth and Moon similar to how crew rotations are currently handled on the International Space Station.

Naturally, there are quite a few technical challenges that need to be addressed before that can happen. A major one is finding ways to safely and accurately deliver multiple payloads to the lunar surface. Building a Moon outpost will be a lot harder if all of its principle modules land several kilometers away from each other, so NASA is partnering with commercial companies to develop crew and cargo vehicles that are capable of high precision landings.

But bringing them down accurately is only half the problem. The Apollo Lunar Module is by far the largest and heaviest object that humanity has ever landed on another celestial body, but it’s absolutely dwarfed by some of the vehicles and components that NASA is considering for the Artemis program. There’s a very real concern that the powerful rocket engines required to gracefully lower these massive craft to the lunar surface might kick up a dangerous cloud of high-velocity dust and debris. In extreme cases, the lander could even find itself touching down at the bottom of a freshly dug crater.

Of course, the logical solution is to build hardened landing pads around the Artemis Base Camp that can support these heavyweight vehicles. But that leads to something of a “Chicken and Egg” problem: how do you build a suitable landing pad if you can’t transport large amounts of material to the surface in the first place? There are a few different approaches being considered to solve this problem, but certainly one of the most interesting among them is the idea proposed by Masten Space Systems. Their experimental technique would allow a rocket engine to literally build its own landing pad by spraying molten aluminum as it approaches the lunar surface.

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Cortex 2 Is One Serious 3D Printed Experimental Rocket

December 25, 2018 by Donald Papp 9 Comments

Rocketry is wild, and [Foaly] is sharing build and design details of the Cortex 2 mini rocket which is entirely 3D printed. Don’t let that fool you into thinking it is in any way a gimmick; the Cortex 2 is a serious piece of engineering with some fascinating development.

Cortex 1 was launched as part of C’Space, an event allowing students to launch experimental rockets. Stuffed with sensors and entirely 3D printed, Cortex 1 flew well, but the parachute failed to deploy mainly due to an imperfectly bonded assembly. The hatch was recovered, but the rocket was lost. Lessons were learned, and Cortex 2 was drafted up before the end of the event.

Some of the changes included tweaking the shape and reducing weight, and the refinements also led to reducing the number of fins from four to three. The fins for Cortex 2 are also reinforced with carbon fiber inserts and are bolted on to the main body.

Here’s an interesting details: apparently keeping the original fins would result in a rocket that was “overstable”. We didn’t really realize that was a thing. The results of overstabilizing are similar to a PID loop where gain is too high, and overcorrection results in oscillations instead of a nice stable trajectory.

Cortex 2 uses a different rocket motor from its predecessor, which led to another interesting design issue. The new motor is similar to hobby solid rocket motors where a small explosive charge at the top of the motor blows some time after the fuel is gone. This charge is meant to eject a parachute, but the Cortex 2 is not designed to use this method, and so the gasses must be vented. [Foaly] was understandably not enthusiastic about venting hot gasses through the mostly-PLA rocket body. Instead, a cylindrical cartridge was designed that both encases the motor and redirects any gasses from the explosive charge out the rear of the rocket. That cartridge was SLA printed out of what looks to us like Formlabs’ High Tempurature Resin.

Finally, to address the reasons Cortex 1 crashed, the hatch and parachute were redesigned for better reliability. A servo takes care of activating the system, and a couple of reverse-polarity magnets assist in ensuring the hatch blows clear. There’s even a small servo that takes care of retracting the launch guide.

The rocket is only half built so far, but looks absolutely fantastic and we can’t wait to see more. It’s clear [Foaly] has a lot of experience and knowledge. After all, [Foaly] did convert a Makerbot printer into a CNC circuitboard engraver.