Spinning Close to a Star.

Whenever I think of a tidally locked planet, like say Mercury, the only image that comes to mind is one that is barren of all life. You see for tidally locked systems the face of the smaller body is always pointing towards the larger one, like our Moon is towards Earth. For planets and suns this means that the surface of the tidally locked planet would typically turn into an inferno with the other side becoming a frigid wasteland, both devoid of any kind of life. However new research shows that these planets might not be the lifeless rocks we once thought them to be and, in fact, they could be far more Earthlike than we previously thought.


Scientists have long theorized that planets of this nature could potentially harbour a habitable band around their terminator, a tenuous strip that exists between the freezing depths of the cold side and the furnace of the hot side. Such a planet wouldn’t have the day/night cycles that we’re accustomed to however and it would be likely that any life that evolved there would have adapted to the permanent daylight. There’d also be some pretty extreme winds to contend with as well due to the massive differences in temperature although how severe they were would be heavily dependent on the thickness of the atmosphere. Still it’s possible that that little band could harbor all sorts of life, despite the conditions that bookended its environment.

However there’s another theory that states that these kinds of planets might not be the one sided hotbeds that we initially thought them to be. Instead of being fully tidally locked with their parent star planets like this might actually still rotate thanks to the heavy winds that would whip across their surface. These winds would push against the planets surface, giving it enough rotation to overcome the tidal locking caused by the parent star’s gravity. There’s actually an example of this within our own solar system: Venus which by all rights should be tidally locked to our Sun. However it’s not although it’s extremely long days and retrograde rotation (it spins the opposite way to every other planet) hints at the fact that its rotation is caused by forces that a different to that from every other planet.

Counterintuitively it seems that Venus’ extremely thick atmosphere might be working against it in this regard as the modelling done shows that planets with thinner atmospheres would actually experience a higher rotational rate. This means that an Earthlike planet that should be tidally locked would likely not be and the resulting motion would be enough to make the majority of the planet habitable. In turn this would mean that many of the supposedly tidally locked planets we’ve discovered could actually turn out to be habitable candidates.

Whilst these are just beautiful models for now they can hopefully drive the requirements for future craft and observatories here on Earth that will be able to look for the signatures of these kinds of planets. Considering that our detection methods are currently skewed towards detecting planets that are close to their parent stars this will mean a much greater hit rate for habitable candidates, providing a wealth of data to validate against. Whether we’ll be able to get some direct observations of such planets within the next century or more is a question we won’t likely have an answer to soon, but hopefully one day we will.


ESA’s IXV Splashes Down After Successful Maiden Flight.

The European Space Agency’s Intermediate eXperimental Vehicle (IXV)  is an interesting platform, ostensibly sharing some inspiration from the United States Air Force’s X-37B but with a very different purpose in mind. The IXV is set to be more of a general purpose craft, one that’s capable of testing new space technologies and running experiments that might not otherwise be feasible. It’s also set to be ESA’s first fully automated craft that’s capable of re-entry, an incredible technological feat that will inevitably find its way into other craft around the world. Today marks the completion of the IXV’s maiden flight, completing a sub-orbital journey that was, by all accounts, wildly successful.


This flight was meant to be conducted towards the end of last year but was delayed due to the novel launch profile that the IXV flight required, something which the launch system wasn’t typically used for. The mission profile remained the same however, serving as a shakedown of all the key systems as well as providing a wealth of flight data around how all the systems functioned during the flight. This included things such as the automated guidance system, avionics and the thermal shielding that coats the bottom of the craft. The total flight time was approximately 100 minutes with the craft making a parachute assisted landing in the Pacific Ocean where it was retrieved by a recovery craft (pictured above).

Whilst the IXV platform is likely to see many more launches in the future it’s actually a stepping stone between a previous craft, the Atmospheric Reentry Demonstrator (ARD), and a future space plane called the Program for Reusable In-orbit Demonstrator in Europe (PRIDE). The ultimate goal of this program is to develop a fully reusable craft that the ESA can use for its missions in space and judging by the design of the IXV it’s a safe bet that it will likely end up looking something like the Space Shuttle. The IXV will never take human passengers to orbit, it’s simply too small to accomplish that feat, however much of the technology used to create it could be easily repurposed to a man rated craft.

I think the ESA has the right approach when it comes to developing these craft, opting for smaller, purpose built craft rather than a jack-of-all trades type which, as we’ve seen in the past, often results in complexity and cost. The total cost of the IXV craft (excluding the launcher) came out to a total of $170 million which is actually cheaper than the X-37B by a small margin. It will be interesting to see if the ESA gets as much use out of their IXV though as whilst it’s a reusable craft I haven’t heard talk of any further flights being planned anytime soon.

It’s great to see multiple nations pursuing novel ways of travelling to and from space as the increasing number of options means that there’s more and more opportunities for us to do work out there in the infinite void. The IXV might not become the iconic craft that it emulates but it will hopefully be the platform that enables the ESA to extend their capabilities far beyond their current station. The next few years are going to be ones of envelope pushing for the ESA and I, for one, am excited to see what they can accomplish.


NASA Investigation Nuclear Propulsion for Future Mars Missions.

Moving things between planets is a costly exercise no matter which way you cut it. Whilst we’ve come up with some rather ingenious ideas for doing things efficiently, like gravity assists and ion thrusters, these things can only take us so far and the trade offs usually come in the form of extended duration. For our robotic probes this is a no brainer as machines are more than happy to while away the time in space whilst the fleshy counterparts do their bits back here on Earth. For sending humans (and larger payloads) however these trade offs are less than ideal, especially if you want to do round trips in a reasonable time frame. Thus we have always been on the quest to find better ways to sling ourselves around the universe and NASA has committed to investigating an idea which has been dormant for decades.


NASA has been charged with the task of getting humans to Mars by sometime in the 2030s, something which shouldn’t sound like an ambitious feat (but it is, thanks to the budget they’ve got to work with). There are several technical hurdles that need to be overcome before this can occur not least of which is developing a launch system which will be able to get them there in a relatively short timespan. Primarily this is a function of the resources required to keep astronauts alive and functioning in space for that length of time without the continual support of launches from home. Current chemical propulsion will get us there in about 6 months which, whilst feasible, still means that any mission to there would take over a year. One kind of propulsion that could cut that time down significantly is Nuclear Thermal which NASA has investigated in the past.

There are numerous types of Nuclear Thermal Propulsion (NTP) however the one that’s showing the most promise, in terms of feasibility and power output, is the Gas Core Reactor. Mostly this comes from the designs high specific impulse which allows it to generate an incredible amount of thrust from a small amount of propellant which would prove invaluable for decreasing mission duration. Such designs were previously explored as part of the NERVA program back in the 1970s however it was cancelled when the supporting mission to Mars was cancelled. However with another Mars mission back on the books NASA has begun investigating the technology again as part of the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) at their Huntsville facility.

NTP systems likely wouldn’t be used for the initial launch instead they’d form part of the later stage to be used once the craft had made it to space. This negates many of the potential negative aspects like radioactive material being dispersed into the atmosphere and would allow for some concessions in the designs to increase efficiency. Several potential craft have been drafted (including the one pictured above) which use this idea to significantly reduce travel times between planets or, in the case of supply missions, dramatically increase their effective payload. Whether any of these will see the light of day is up to the researchers and mission planners at NASA but there are few competing designs that provide as many benefits as the nuclear options do.

It’s good to see NASA pursuing alternative ideas like this as they could one day become the key technology for humanity to spread its presence further into our universe. The decades of chemical based rocketry that we have behind us have been very fruitful but we’re fast approaching the limitations of that technology and we need to be looking further ahead if we want to further our ambitions. With NASA (and others) investigating this technology I’m confident we’ll see it soon.


Beagle 2 Found on Mars after 11 Years.

The Mars Curse is the term used to describe the inordinately high failure rate for missions to our red celestial sister, particularly those that dare to touch the surface. It’s an inherently complicated mission as there are innumerable things that need to be taken into account in order to get something on the surface and a problem with any one of the systems can result in a total mission failure. One such mission that fell prey to this was the European Space Agency’s Beagle 2, a small lander that hitched a  ride with the Mars Express craft all the way back in 2003. Shortly after it was sent down to the surface contact with the probe was lost and it was long thought it met its end at an unplanned disassembly event. However we’ve recently discovered that it made all the way down and even managed to land safely on the surface.


Like the Mars Exploration Rovers Beagle 2 would use the martian atmosphere to shed much of its orbital velocity, protected by its ablative heat shield. Once it approached more manageable speeds it would then deploy its parachutes to begin the final part of its descent, drifting slowly towards the target site. Then, when it was about 200m above the ground, it would deploy airbags around its outer shell to protect it from the impact when it hit the surface. Once on the ground it would then begin unfurling its solar panels and instrumentation, making contact with its parent orbiter once all systems were nominal. However back on that fateful day it never made contact and it was assumed the lander likely destroyed.

The information we now have points towards a different story. It appears that pretty much everything went according to plan in terms of descent which, as my very high level description of the process can attest to, is usually the part when things go catastrophically wrong. Instead it appears that Beagle 2 made it all the surface and began the process of deploying its instruments. However from what we can see now (which isn’t much given that the lander is some 2m across and our current resolution is about 0.3m/pixel) it appears that it didn’t manage to unfurl all of its solar panels which would have greatly restricted its ability to gather energy. My untrained eye can see what looks like 2 panels and the instrumentation pod which would leave it with about half the power it was expecting.

In my opinion though (which should be taken with a dash of salt since I’m not a rocket scientist) there must have been some damage to other systems, most likely the communications array, which prevented it from making initial contact. I’d assume that there was enough charge for it to complete it’s initial start up activities which should have been enough to make initial contact with the orbiter. Such damage could have occurred at any number of points during the descent and would explain why there was total silence rather than a few blips before it dropped off completely. Of course this is just pure speculation at this point and we’re not likely to have any good answers until we actually visit the site (if that will ever happen, I’m looking at you Mr Musk).

Still discovering Beagle 2’s final resting place is a great find for all involved as it shows what went right with the mission and gives us clues as to what went wrong. This information will inform future missions to the red planet and hopefully one day we can write off the Mars curse as simply a lack in our understanding of what is required for a successful interplanetary mission. Indeed the bevy of successful NASA missions in the past decade is a testament to this constant, self correcting trial and error process, one that is built on the understanding gleaned from those who’ve come before.


Hitting a Bullseye From Orbit: SpaceX’s Automated Landing System.

Reducing the cost of getting things into orbit isn’t easy, as the still extremely high cost of getting cargo to orbit can attest. For the most part this is because of the enormous energy requirement for getting things out of Earth’s gravity well and nearly all launch systems today being single use. Thus the areas where there are efficiencies to be gained are somewhat limited, that is unless we start finding novel methods of getting things into orbit. Without question SpaceX is at the forefront of this movement, having designed some of the most efficient rocket engines to date. Their next project is something truly novel, one that could potentially drop the total cost of their launches significantly.


Pictured above is SpaceX’s Autonomous Spaceport Drone, essentially a giant flat barge  that’s capable of holding its position steady in the sea thanks to some onboard thrusters, the same many deployable oil rigs use. At first glance the purpose of such a craft seems unclear as what use could they have for a giant flat surface out in the middle of the ocean? Well as it turns out they’re modifying their current line of Falcon rockets to be able to land on such a barge, allowing the first stage of the rocket to be reused at a later date. In fact they’ve been laying the foundations of this system for some time now, having tested it on their recent ORBCOMM mission this year.

Hitting a bullseye like that, which is some 100m x 30m, coming back from orbit is no simple task. Currently SpaceX is only able to get their landing radius down to an area of 10KM or so, several orders of magnitude higher than what the little platform provides. Even with the platform being able to move and with the new Falcon rockets being given little wings to control the descent SpaceX doesn’t put their chances higher than 50% of getting a successful landing the first time around. Still whilst the opportunity for first time success might be low SpaceX is most definitely up to the challenge and it’ll only be a matter of time before they get it.

The reason why this is such a big deal is that any stage of the rocket that can be recovered and reused drastically reduces the costs of future launches. Many people think that the fuel would likely be the most expensive part of the rocket however that’s not the case, it’s most often all the other components which are the main drivers of cost for these launch systems. Thus if a good percentage of that craft is fully reusable you can avoid incurring that cost on every launch and, potentially, reduce turnaround times as well. All of these lead to a far more efficient program that can drive costs down, something that’s needed if we want to make space more accessible.

It just goes to show how innovative SpaceX is and how lucky the space industry is to have them. A feat like this has never been attempted before and the benefits of such a system would reach far across all space based industries. I honestly can’t wait to see how it goes and, hopefully, see the first automated landing from space onto a sea platform ever.


Curiosity Smells Farts on Mars.

There’s many ways to look for life on other planets. Most of our efforts currently focus on first finding environments that could sustain life as we know it which is why the search (and subsequent discovery) of water on other celestial bodies is always a cause for celebration. Once we’ve got a target though the search needs to become more nuanced as we have to seek out the clues that life leaves behind or the blocks that build it. For life as we know it one of the first things we can look for is the presence of organic molecules, the essential parts that make up all of life as we know it. One of these such molecules is methane, reknown for being a component in flatulence, something which Curiosity recently detected on Mars.


Methane, and other organic compounds, don’t necessarily require life in order to form however their presence does indicate that there was an environment favourable to life at one point in time. For Mars this was some time ago, on the order of billions of years, and so it’s highly unlikely that any remaining methane is due to microbial activity. However there has to be some local source of methane near Curiosity as it detected a ten fold spike in the amount of methane in Mars’ atmosphere, something which it has never seen before. Additionally Curiosity detected other organic molecules in a rock it drilled into recently, indicating that there was a time when organics must have been prevalent across the entire surface of Mars.

The discovery was made sometime ago however the researchers needed to rule out the possibility that the reading was caused by organics that were trapped in Curiosity’s sensors from Earth. Things like this happen more often than you think as whilst we take every precaution to ensure that there isn’t any contaminations on craft like this it’s inevitable that the sensors, all of which are highly complex machines, end up having stray molecules trapped within them. Because of that however we’ve gotten pretty good at identifying when things came along for the ride and this particular methane spike didn’t originate from Earth.

The organics in the rock are most intriguing however as they tell a story of Mars’ atmosphere that stretches back to the point where it still held liquid water on its surface. The ratio of isotopes in the water (which I talked about yesterday in regards to the discoveries Rosetta has made) indicates that the mineral formed some time after Mars lost much of its water, if we assume that the water on Mars and Earth came from the same place. However the ratio is also radically different to the water in Mars’ atmosphere today indicating that it formed before Mars lost the rest of its surface water. It will be interesting to see how this sample compares to other places around Mars as it will paint a detailed picture of the planet’s surface over time.

It seems like it will be only a matter of time before we find a large source of water on Mars, buried deep beneath the surface somewhere. From there we’ll have an exciting period of analysis to determine if microbial life still thrives on what appears to be a dead planet. Unfortunately that’s not likely to happen any time soon, at least not until we get people there anyway, but with NASA recommitting themselves to such an endeavour it might come sooner than many first thought. Honestly I can’t wait for that to occur as it will shed so much light on how life evolves and, possibly, what it can become.


Rosetta’s Data Provides Clues to Origins of Water on Earth.

The origin of Earth’s water is still something of an open debate. The popular theory at the moment is that the primordial Earth was far too hot to contain any form of liquid water, its molten surface still reeling from the cataclysmic events that led to its creation. However others postulate that the water was trapped deep below the surface, only to arise later on as the Earth cooled and an atmosphere developed. It’s an interesting question not only because of how fundamental water is to life but also because we seem to have a lot more of it than any other planet in the solar system. Thus the question of where it came from, and why it’s managed to stick around for so long, is one of continuous scientific enquiry, including such missions as the recently celebrated Rosetta probe.


If we run with the theory that Earth’s water came from some extraplanetary source then the question turns to what the original source might be. Comets seem like a good candidate as they’re primarily water ice by composition and were far more common during the early stages of Earth’s life than they are now. However measurements of isotopes within water of several comets, including Halley, Hyakutake  and Hale-Bopp has shown that they are not likely the primary source of water that’s currently on Earth’s surface. The composition of water found on asteroids and other water formed minerals on the Moon seem to indicate that a source closer to home is far more likely which Rosetta’s latest data appears to confirm.

The comet that Rosetta was investigating, the romantically named 67P/Churyumov–Gerasimenko, has a ratio of isotopes that is completely different to anything that’s seen on Earth. The reason that this is important is due to it’s orbit as 67P is what we call a Jupiter class comet, a collection of various comets that have orbits that don’t extend far past Jupiter. It was thought that these kinds of comets would have been more likely to have been involved in the creation of Earth’s oceans than comets from further out, due to their proximity. However 67P, with its wildly different composition to Earth (and even other bodies in the same vicinity), lends credence to the idea that comets aren’t the likely source of Earth’s oceans. Indeed it’s far more likely that water and minerals trapped in asteroids are the likely source, based on how similar their composition is.

Now this doesn’t rule out comets completely as there’s potential for further out Kuiper belt class comets to have the composition we’re looking for but it’s looking far more likely that objects from within the asteroid belt are responsible for the oceans we have today. What the mechanism was for them making their way to Earth, whether it was early on in the cataclysmic forming of our solar system or later on when things calmed down, is something that’s still an open question. It’s one we might also have answers to very soon as Dawn is scheduled to arrive at Ceres early next year, the biggest object in the asteroid belt. What Dawn finds there might be the key to unlocking the secrets of our Earth’s oceans and, potentially, the asteroid belt itself.

Orion Exploration Flight Test

NASA’s Orion Takes Flight.

Since before the Shuttle’s retirement back in 2011 NASA has been looking towards building the next generation of craft that will take humans into space. This initially began with the incredibly ambitious Ares program which was set to create a series of rockets that would be capable of delivering humans to any place within our solar system. That program was cancelled in 2010 by President Obama and replaced with a more achievable vision, one that NASA could accommodate within its meagre budget. However not all the work that was done on that program was lost and the Orion capsule, originally intended to ride an Ares-I into space, made its maiden flight last week signalling a new era for NASA.

Orion Exploration Flight Test

The profile for this mission is a fairly standard affair, serving as a shakedown of all the onboard systems and the launch stack as a whole. In terms of orbital duration it was a very short mission, lasting only 2 orbits, however that orbit allowed them to gather some key data on how the capsule will cope with deep space conditions. It wasn’t all smooth sailing for the craft as the mission was meant to launch the day before however a few technical issues, mostly to do with the rockets, saw NASA miss the initial launch window. However the second time around they faced no such issues and with the wind playing nice Orion blasted off for its twice around the world voyage.

When I first read about the mission I was curious as to why it was launching into such an unusual orbit. To put it in perspective the apogee (the point of the orbit furthest away from the earth) was some 5,800KM which is an order of magnitude higher than anything else in low Earth orbit. As it turns out this was done deliberately to fling the Orion capsule through the lower Van Allen belt. These belts are areas of potentially damaging radiation, something which all intersolar craft must pass through on their journey to other planets in our solar system. Since Orion is slated to carry humans through here NASA needs to know how it copes with this potential hazard and, if there are any issues, begin working on a solution.

The launch system which propelled the Orion capsule into orbit was a Delta-IV Heavy which currently holds the crown for the amount of payload that can be delivered to low Earth orbit. It will be the first and last time that we’ll be seeing Orion riding this rocket as the next flight, slated for launch towards the end of 2018, will be the Space Launch System. This is the launch system that replaced the Ares series of rockets when Obama cancelled the Constellation program and will be capable of delivering double the payload of the Delta-IV Heavy. It’s going to need that extra power too as the next Orion mission is an uncrewed circumlunar mission, something NASA hasn’t done in almost 5 decades.

It’s great to see progress from NASA, especially when it comes to its human launch capabilities. The Shuttle was an iconic craft but it simply wasn’t the greatest way to get people into space. The Orion however is shaping up to be the craft that might finally pull NASA out of the rut it’s found itself in ever since the Apollo missions ended. We’re still a while off from seeing people make a return to space on the back of a NASA branded rocket but it’s now a matter of when, and not if, it will happen.

DNA Helix

DNA Can Survive in Space, Re-Entry into Atmosphere.

There’s a few competing theories around how life came to be on our planet. One of them is the theory of abiogenesis, the idea that the building blocks of life assembled themselves from the primordial soup of the Earth to eventually give rise to life as we know it today. As an origin for all life it makes sense as it had to come from somewhere although whether or not it was how life came to be here is still up for question. Indeed the competing theory for how life originated here comes in the form of panspermia, the notion that our world was somehow seeded with life from planets elsewhere. Whilst it’s likely impossible to prove either of these theories they do lead to some interesting  areas of scientific research, the latter of which just bore some interesting fruit.

DNA HelixOne of the biggest questions with the idea of panspermia is whether or not the building blocks of life could survive in the harsh climate of space. We have known for some time that simple forms of life are able to tolerate the conditions of space for what seems like an eternity but given the time frames involved it’s far more likely that their genetic components would be the only things that would survive the long journey through space. Whether or not DNA could survive some of the most harsh conditions, like plunging back into the Earth’s atmosphere at re-entry speeds, is a question that researchers at the University of Zurich attempted to answer.

The results are quite intriguing, showing that the DNA molecules (which were applied to the outside of the craft with no shielding to speak of) was still viable upon returning to Earth. Whilst it’s far from a long duration spaceflight, the TEXUS launch system is a sub-orbital platform, it does show that DNA is very resilient to the harsh conditions experienced in space, lending credence to the idea that our Earth may have been seeded with genetic material of alien origin. Just how that material would have ended up finding it’s way here though is another question entirely, although it is an interesting one.

Genetic material lacks the capability to launch itself into space and so the only way it finds its way off a planet (bar ours) is to hitch a ride on a cataclysmic event. Large asteroids that impact a planet shoot up all manner of ejecta, some with enough energy to escape their planet’s gravity entirely. It’s a rare event, to be sure, however it’s happened often enough that we’ve got numerous bits of Mars scattered on Earth’s surface and likely bits of other planets that we don’t yet know about. If just a few of these kinds of asteroids hit Earth at the right time our origins of life might lie far beyond our own planet, or possible even our own galaxy.

It never ceases to amaze me just how resilient the building blocks of life are, being able to survive the harshest conditions and still remain viable. This then leads onto us finding life in all sorts of weird places, ones where you’d think it’d be impossible for anything to survive. I honestly can’t wait for the day when we find life on another planet, even if its microbes, as it will tell us so much about who we are and where we came from.


Firefly Alpha

Firefly Space Systems’ Novel Approach to Rocketry.

If there’s one thing we can’t have enough of it’s different companies providing access to space. Whilst much of the progress in the private space industry might be attributable to a couple companies they will need some healthy competition in order to keep them in check, lest they fall into the same traps that their old space predecessors did. Indeed many of these new space companies that are cropping up are pursuing technologies that others have let slip by the wayside, some of which deserve thorough investigation. Firefly Space Systems, founded at the beginning of this year by a former SpaceX engineer, is the latest company to try its hand at providing access to space and it’s doing so in a very novel way.

Firefly Alpha

Shown above is the concept for their Firefly Alpha which employs several novel technologies that you likely won’t have seen on any other craft before. For starters much of the launch body will be made of composite materials, similar to that of other private space start up Rocket Lab. The engines on the bottom are also noteworthy as they’re arranged as a plug-type aerospike, an engine type that’s been built (and tested) by numerous parties in the past but has never been used in a production craft before. The design also incorporates an autogenous (self pressurizing) fuel system, something which has the potential to make the craft far more efficient than other designs. All in all the design is quite impressive as the trade-offs it makes are radically different to those of more traditional rocket designs.

It’s going to be interesting to see how the composite designs perform as whilst the idea has been somewhat validated by Rocket Lab there’s yet to be a full sized rocket launch using it. Should the idea scale up to the levels that both Firefly and Rocket Lab require then there’s a lot of potential for their systems to be far more efficient than their more traditional brethren, although I’m sure there’s some trade offs that will have to be made. What they are and whether or not they’re worth it is something I can’t really determine (I am not a rocket scientist) but I’d doubt the drawbacks would be that severe considering 2 independent companies are pursuing it.

I’ve always been a fan of the aerospike design, mostly because the pure torodial ones look like something out of science fiction, but I know the reason why they’ve never made their way into a production craft. They’re a jack-of-all trades deal, maintaining approximately the same efficiency under all circumstances whilst not really excelling in any one of them. Traditional rocket design accommodated this by using different types of engines during different stages, something which has worked pretty well for pretty much all launch platforms. The question that Firefly will have to answer is whether the trade off of better efficiency closer to sea level (something all current rocket engines struggle with) outweighs the reduced efficiency in a vacuum when compared to the bell type engines. I’m sure the modelling they’ve done tells them yes but nothing beats real data when it comes to rocketry.

The real secret sauce of their design might be in the self-pressurizing fuel tanks, something which I’m not sure I’ve seen in any other rocket design before. In traditional rockets as the fuel is depleted it’s replaced by a pressurized gas so that the pressure within the tank remains constant. This means that you have to carry that gas and its associated systems with you, reducing your overall payload capacity. Firefly’s system instead uses it’s own fuel, in this case methane, which is routed around the aerospike to cool it (a common technique) and then pumped back into the fuel chamber as a gas. Then once all the fuel is spent the gas can also be used to provide a last bit of thrust, something the inert gas style models can’t readily achieve. If it works the way they say it does there’s quite a lot of potential for this plucky rocket as that little bit of extra efficiency could be enough to offset all their other trade offs.

All in all I like Firefly’s rocket design as it incorporates both novel design decisions as well as trade offs that most traditional rocket companies don’t make. The overall system could end up being vastly more efficient than its individual components, something which I don’t think many other launch companies consider when looking at these technologies in isolation. Whether it will all come together is something we’ll be waiting a while for though as this nascent company likely won’t be launching anything for a couple years. Still I’m eager to see what they can accomplish as we can never have too many people tackling the issue of getting access to space.