Space

Space Launch System Configurations

NASA Approves SLS, Probably Shouldn’t Have.

Ever since the retirement of the Space Shuttle the USA has been in what’s aptly describes as a “launch gap”. As of right now NASA is unable to launch its own astronauts into space and instead relies completely on the Russian Soyuz missions to ferry astronauts to and from the International Space Station. This isn’t a particularly cheap exercise, coming in at some $70 million per seat, making even the bloated shuttle program look competitive by comparison. NASA had always planned to develop another launch system, originally slated to be dubbed Ares and developed completely from scratch, however that was later scrapped in favour of the Space Launch System which would use many of the Shuttle’s components. This was in hope that the launch gap could be closed considerably, shortening the time NASA would be reliant on external partners.

Space Launch System Configurations

News comes today that NASA has approved the funding for the project which is set to total some $6.8 billion over the next 4 years. The current schedule has the first launch of the SLS pegged for some time in 2017 with the first crewed mission to follow on around 4 years later. Developing a whole new human rated launch capability in 7 years is pretty good by any standards however it also begs the question as to whether or not NASA should be in the business of designing and manufacturing launch capabilities like this. When Ares and SLS  were first designed the idea of a private company being able to provide this capability was still something of a fantasy however that’s no longer the case today.

Indeed SpaceX isn’t too far off deploying their own human rated craft that will be capable of delivering astronauts to the ISS, Moon and beyond. Their current schedule has the first crewed Dragon flight occurring no sooner than 2015 which, even with some delays here and there, would still have it happening several years before the SLS makes its manned debut. Looking at the recent Dragon V2 announcement it would seem like they’re well on their way to meeting those deadlines which will give the Dragon several years of in-flight usage before the SLS is even available. With NASA being far more open to commercial services than they used to be it does make you wonder what their real desire for the SLS is.

There’s an argument to be made that NASA has requirements that commercial providers aren’t willing to meet which, when it comes to human rated vessels, is mostly true. Man rating a launch system is expensive due to the numerous requirements you have to meet so most opt to just not do it. SpaceX is the notable exception to this as they’ve committed to developing the man rated Dragon even if NASA doesn’t commit to buying launches on it. Still the cash they’re dropping on the SLS could easily fund numerous Dragon launches, enough to cover NASA off for the better part of a decade if my finger in the air maths is anything to go by.

The only argument which I feel is somewhat valid is that NASA’s requirement for heavy lift outstrips pretty much any commercially available launch system available today. There’s really not much call for large single payloads unless you’re shipping humans into space (we’ve got an awfully long list of requirements compared to our robotic cousins) and so most of the big space contractors haven’t built one. SpaceX has plans to build rockets capable of doing this (the Falcon XX) although their timeframes are somewhat nebulos at this point in time. Still you could use a small portion of the cash set aside for the SLS in order to incentivise the private market to develop that capability as NASA has done quite successfully with its other commercial programs.

I’ve long been of the mind that NASA needs to get out of the launch system business so they can focus their time and resources on pushing the envelope of our capabilities in space. The SLS might fill a small niche that’s currently unserviced but it’s going to take its sweet time in getting there and will likely not be worth it when it finally arrives.

SpaceX Dragon V2 Capsule

SpaceX’s Dragon V2 is Just Incredible.

SpaceX’s Dragon capsule has proved to be an incredibly capable craft. Ever since it made it’s debut journey to the International Space Station back in 2012 the craft has made another 3 trips as part of the Commercial Resupply Services contract that SpaceX has with NASA. Should all things go to plan then 2014 will be the Dragon’s busiest year yet with a grand total of 4 launches planned, 3 of those to occur within a couple months of each other. Still the current Dragon is only half the puzzle for SpaceX as whilst it’s quite capable of delivering cargo to the ISS the human carrying variant has remained as a concept for quite some time. However that all changed last week when SpaceX announced the Dragon V2 capsule.

SpaceX Dragon V2 Capsule

The original Dragon capsule was readily comparable to Soyuz and Apollo style craft, except for the fact that it couldn’t carry a single human into or back from orbit. The Dragon V2 on the other hand is really unlike any other craft, being able to carry up to 7 astronauts (equal to that of the Space Shuttle) and also with the capability to soft land anywhere on Earth within a very small area. That’s something that no other craft has ever been able to boast previously as even the venerable Space Shuttle required a runway to land and there were only 2 places on Earth capable of receiving it. Other notable improvements include fully automated docking and the world’s first fully 3D printed rocket engine, the SuperDraco.

Inside the capsule is when things start to get really impressive. however. If you’ve ever seen the inside of a Soyuz capsule you’ll know things are pretty tight in there and the Dragon V2 isn’t that much bigger. The interior design of the Dragon is where the big differences come in to play as you can see in the screen capture above. That giant screen flips down from the ceiling, making ingress and egress from the capsule extremely easy whilst at the same time providing a lot more room inside the capsule than you’d traditionally see in a craft of this nature. I’m guessing that they’re likely touchscreens as well, providing an incredible amount of flexibility in turns of what those panels can be capable of.

The ability to land anywhere in the world, even on land, is a pretty incredible achievement for SpaceX. Right now when astronauts and cosmonauts come back from space they come back on what’s called a ballistic trajectory, I.E. they’re falling to the ground like a rock. The Soyuz capsules have “soft landing” rockets which fire moments before they hit the ground to reduce the impact however they still get rolled head over heels several times before coming to a complete stop. The Dragon V2 is luxury by comparison, able to come to a soft landing right side up every time. Whilst many of the launches and landings will occur at the same places (due to orbital mechanics for the most part) the ability to land somewhere else, especially in an emergency, is an incredibly useful feature to have.

If everything goes perfectly we could see the first unmanned demonstration flight of the new Dragon capsule towards the end of next year with the first crewed mission coming in 2016. That’s likely to slip, something which NASA is prepared for as they have secured spots on Soyuz craft through 2017, but even that is a pretty incredible turnaround for a manned craft. Indeed SpaceX will achieved in under 20 years what many government agencies took far longer to accomplish and it seems like they have no intention of slowing down.

Descend Through Titan’s Haze.

Our spacecraft have reached nearly every corner of our solar system, from the barren sun baked world of Mercury to the (soon to be visited) frigid ice ball of Pluto. We’ve gazed at all of them from afar many times but there are precious few we have made even robotic footfall on, with only a single other heavenly body having human footprints on it. Still from those few where we’ve been able to punch through the atmosphere the scenery we’ve been greeted with has been both strangely familiar yet completely alien. Mars is most famous of these but few are aware of the descent video from the Huygens probe that it made on its way down to Titan’s surface:

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Titan gets its thick orange atmosphere from its mostly nitrogen atmosphere being tainted by methane which is thought to be constantly refreshed by cryovolcanoes on its surface. Whilst the mountain ranges and valleys you see were formed in much the same way as they were here on Earth those lakes you see in between them aren’t water, but hydrocarbons. Indeed much of Titan’s surface is covered in what is essentially crude oil although making use of it for future missions would likely be more trouble than its worth.

Still it’s amazing to see worlds that are so like ours in one aspect yet completely foreign in so many other ways. This rare insight into what Titan looks like from on high is not only amazing to see but it has also provided invaluable insight into what Titan’s world actually is. I honestly could watch videos like this for hours as it’s just so mesmerizing to see the surface of worlds other than our own.

Europa

An Armchair Scientist’s Mission To Europa.

If there’s any place in our solar system that we’d want to start seriously looking for life it’d be Europa. The dust covered snowball of a moon likely contains a vast subsurface ocean, one that is kept liquid by the giant gravitational forces of its host planet Jupiter. This makes Europa a great candidate for life as we know it as once we find water it’s inevitable that we find life shortly thereafter. The challenge with Europa though is getting to that subsurface ocean to study it as it could be covered in several kilometers of water ice, not something you can simply puncture through. Whilst there are numerous people more qualified than me on this subject, many of them actually working in the aerospace industry, with NASA asking for ideas for a potential mission to Europa I figured I’d throw my 2 cents in.

Europa

So the total budget for the potential mission is a cool $1 billion and whilst that sounds like a lot of money projects that I’d consider simpler than my idea (like say Curiosity which was $2.5 billion) but I think there’s potential to build a platform that could fuel further missions. With that in mind this initial mission is likely only to be a scouting mission, one that will give us the most detailed picture of Europa possible so that the follow up mission can choose the perfect site to land on and commence the search for life in its vast underground ocean. My proposal then is to develop a compact nuclear reactor (not a RTG) to power a scouting craft laden with instruments to analyse the gravitic field and surface of Europa. This craft will be able to find the point at which the surface ice is the thinnest and identify potential landing sites for the second generation craft: a cryobot that will punch through to the ocean below.

Putting a nuclear reactor into space might sound like the plan of a crazed sci-fi nerd but there’s actually been dozens of small prototype reactors launched into space with all of them proving to be safe and reliable. The power capabilities of such a reactor are far beyond that of what a small satellite would usually require however attempting to melt through kilometers of ice will require power of that scale. Thus it would make sense to fund research into developing the power supply first and then validating it on the scouting craft. Then, once that mission is successful, the reactor can be scaled to the appropriate dimensions for the cryobot mission and even used in other deep space programs.

Having such a generous amount of power available also opens up the opportunity to using instruments on the scouting craft which would not be feasible, typically. Things like high-power antennas (which could function as a relay for the follow up mission), radar imagers or bigger and better versions of other instruments. My knowledge on the power requirements of various instruments is limited but I know that even the most advanced RTGs, like the one in Curiosity, produce a measly 125W. Being able to draw on several kilowatts, an order of magnitude more power, seems like it would open up many opportunities that just weren’t possible previously.

I’m probably vastly underestimating how much it would cost to develop such technology, especially in today’s nuclear hostile political environment, but if we’re serious about actually digging under Europa’s surface I don’t see what our other options would be. Melting through giant sheets of ice is no small task and one that has requirements that far surpass anything we have currently. Using that $1 billion mission to set ourselves up for future exploration seems like the best bet especially considering how many other applications a safe, small nuclear reactor would have.

Orion_with_ATV_SM

NASA’s Ambitious Asteroid Capture Mission.

Whilst the debate among the space enthusiast community still rages about what the next target for human exploration should be those with the capability seem to have already made a decision: we’re going to Mars. NASA has committed to getting astronauts there some time around 2030 and SpaceX’s founder and CEO, Elon Musk, has long held the dream that he’d be retiring on Mars. There’s also the Mars One which, to my surprise, is still going and garnering attention worldwide even here in my home country. The lack of a return mission to the Moon does raise some questions about the technology that will be used as we don’t have any craft capable of going past low earth orbit, not since the Apollo program ended almost half a century ago.

Orion_with_ATV_SMNASA has been working on a new crew capsule for some time now, dubbed the Orion. Initially this was part of the planned 2020 mission to return to the Moon however the majority of that was scrapped in favour of going directly to Mars. The capsule and the revised launch system were retained however and will form the basis of NASA’s future manned space missions. However if the Moon is no longer the goal for this craft and it’s end goal will be long duration flight there’s a lot of testing that needs to be done before we send one of them to Mars. Interestingly NASA has gone for an incredibly ambitious mission to put the Orion’s long duration flight capabilities to the test: an asteroid capture and analysis mission.

There’s currently two mission profiles being considered, both of them seeming like something straight out of science fiction. The first (and I’ll guess least likely of the two) is a robotic craft will make its way to a large asteroid, break a chunk of it off and then bring it back into orbit around the moon. The second would be a straight up asteroid capture with the craft grabbing an asteroid in its entirety (it would be small, about 7m or so in diameter) and, again, putting it into lunar orbit. Then once the asteroid is in a stable orbit NASA will send crew to it in an Orion capsule to study it, testing out some of the long duration capabilities as well as other rudimentary space activities like EVAs.

Such a mission is actually quite feasible (at least the latter profile) from a technical perspective. Pretty much all the technology required to capture an asteroid of that size is available today and there’s already 6 candidate asteroids identified. The main issue I see with it is time as just getting to the asteroid is planned to take at least 4 years with another 2 to 6 required for it to make the trip back. That means if the mission were to launch today it could potentially take up to 2024 before it returns to us which doesn’t leave a lot of time for NASA to test out the Orion capsule on it, This could be sped up considerably by changing it’s launch profile to include a second stage rocket to boost it rather than relying on the ion thrusters to achieve escape velocity but that would come with additional expense. There’s also the possibility of foregoing the robotic part of this mission completely and just sending humans although that poses just as many challenges as going straight to mars.

I’m glad to see NASA making a return to missions like these, ones that truly push the envelop of humanity’s space capabilities. It’s going to be interesting to see how the mission develops as there’s lots of different variables that need to be sorted out, some that will change the mission dramatically. Still the thought of us being able to capture an asteroid, bring it into lunar orbit and then send humans to study it is just an incredible thing to think about and I truly hope NASA sees this one through to fruition.

 

ESA IXV Full Scale Prototype

ESA’s New Spacecraft Shows Engineers are Obsessed with Tiny Shuttles.

There’s no denying that the Space Shuttle was an unique design being the only spacecraft that was capable aerodynamic flight after reentry. That capability, initially born out of military requirements for one-orbit trips that required significant downrange flight, came at a high cost in both financial and complexity terms dashing any hopes it had of being the revolutionary gateway space it was intended to be. A lot of the designs and engineering were sound though and so it should come as little surprise to see elements of it popping up in other, more modern spacecraft designs. The most recent of those (to come to my attention at least) is the European Space Agency’s Intermediate eXperimental Vehicle, a curious little craft that could be Europe’s ticket to delivering much more than dry cargo to space.

ESA IXV Full Scale PrototypeWhilst this might not be an almost exact replica like the X-37B is it’s hard to deny that the IXV bears a lot of the characteristics that many of us associated with the Space Shuttle. The rounded nose, blackened bottom, white top and sleek profile are all very reminisicent of that iconic design but that’s where the similarities end. The IXV is a tiny little craft weighing not a lot more than your typical car and lacking the giant wings that allowed the Shuttle to fly so far. This doesn’t mean it isn’t capable of flight however as the entire craft is a lifting body, capable of generating lift comparable to a winged aircraft. Steering is accomplished 2 little paddles attached to the back enabling the IXV to keep its thermal protective layer facing the right direction upon reentry. For now the IXV is a completely robotic craft with little room to spare save for a few on board experiments.

Much like the X-37B the IXV is being designed as a test bed for the technologies that the ESA wants to use in upcoming craft for future missions. Primarily this relates to its lifting body profile and the little flaps it uses for attitude control, things which have a very sound theoretical basis but haven’t seen many real world applications. If all goes according to plan the IXV will be making its maiden flight in October this year, rocketing up to the same altitude as the International Space Station, nearly completing an orbit and then descending back down to earth. Whilst it’s design would make you think it’d then be landing at an air strip this model will actually end up in the Pacific ocean, using its aerodynamic capabilities to guide it to a smaller region than you could typically achieve otherwise. It also lacks any landing gear to speak of, relying instead on parachutes to cushion its final stages of descent.

Future craft based on the IXV platform won’t be your typical cargo carrying ISS ferries however as the ESA is looking to adapt the platform to be an orbital platform, much like the Shuttle was early on in its life. The downrange capability is something that a lot of space fairing nations currently lack with most relying on Russian craft or pinning their hopes on the capabilities of the up and coming private space industry. This opens up a lot of opportunities for scientists to conduct experiments that might be cost prohibitive to complete on the ISS or even ones that might be considered to be too dangerous. There doesn’t appear to be any intention to make an IXV variant that will carry humans into space however, although there’s already numerous lifting body craft in various stages of production that are aiming to have that capability.

It’s going to be interesting to see where the ESA takes the IXV platform as it definitely fills a niche that’s currently not serviced particularly well. Should they be able to transform the IXV from a prototype craft into a full production vehicle within 3 years that would be mightily impressive but I have the feeling that’s a best case scenario, something which is rare when designing new craft. Still it’s an interesting craft and I’m very excited to see what missions it will end up flying.

Cassini Saturn Hexagon

Saturn’s Hexagon and a Table Covered in Clay.

One of the strangest phenomena I’ve ever read about in our solar system (and there are many, like Venus spinning in the opposite direction to everyone else, but that’s a story for another day) none are more perplexing than the hexagon atop of Saturn. It’s strange because shapes like that don’t typically appear in nature, especially at scales of that magnitude. The question of how it came to be, and more importantly why it keeps sticking around, was an interesting one and whilst there’s a sound scientific explanation for it a video shared to me by a friend showcases how the effect can come about.

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You can see the effect most strongly at around 2:30 where he starts moving from the center of the spinning disk back towards the outer edge and, lo and behold, suddenly we have a hexagon shape created by a simple motion on a rotating disk. It’s easy to make the comparison between the spinning disk and the incredible winds that sweep across Saturn’s surface, but what about the artist’s arm motion? We can see it’s a simple periodic, much like a pendulum, but the scale of which these two forces act on would almost preclude any kind of relationship. As it turns out there are in fact some similarities but the mechanisms of action are far more complex.

The current theory is that the hexagon isn’t created by the wind currents per se, as the original spinning a bucket of water experiment would lead you to believe, instead its created by the differing wind speeds that are present throughout Saturn’s atmosphere. These differing wind speeds buffet against each other creating vortexes, eddies and waves. As it turns out Saturn’s north pole has the steepest wind gradient which gives rise to the hexagon. With this in mind the researchers created a system whereby they could spin a cylinder and its base at different speeds creating a gradient similar to that on Saturn and, with a little tweaking, a hexagon appeared.

Now you know all that you should take a look at the latest movie of Saturn’s north pole from Cassini showing the speed gradient in effect. Absolutely incredible, don’t you think?

Venus Atmospheric Maneuverable Platform VAMP

VAMP: Flying High in Venus’ Atmosphere.

It’s almost scary how similar Earth and Venus are in some respects. We’re roughly the same size, with Earth edging Venus out by 300KMs in diameter, and consequently roughly the same mass as well. The similarities end when you start looking further however with Venus being the hottest planet in our solar system due to its runaway greenhouse effect, it’s atmosphere a choking combination of carbon dioxide, nitrogen and sulphur. If there was ever a warning about the devastating potential about greenhouse gases it is our celestial sister Venus, but in that chaos lies an abundance of scientific data that could help us better understand ourselves and, hopefully, avoid the same fate.

Venus Atmospheric Maneuverable Platform VAMPStudying Venus’ atmosphere isn’t an easy task however as those extreme conditions have meant that the longest our probes have managed to survive down there is a couple hours. We can still do a lot of good work with satellites and spectral analysis but there’s really no substitute for actually being in the atmosphere for an extended period of time. Strangely enough whilst Venus’ atmosphere might be one of the most unforgiving in our solar system its composition, made up primarily of heavy than air elements, provides an unique opportunity that an atmospheric study craft could take advantage of. A concept craft that does just this is called the Venus Atmospheric Maneuverable Platform (VAMP) by Northrop Grumman.

The VAMP is part airship, part traditional aircraft which would spend the majority of its life high in Venus’ atmosphere. To do this the VAMP craft is extremely light, on the order of 500kgs, but it has a wingspan that exceeds that of a Boeing 737. The craft itself would be inflatable, allowing VAMP to cruise at altitudes between 55KM and 70KM above Venus’ surface. It can do this because of the incredible density of Venus’ atmosphere which makes even regular breathable air from Earth a powerful lifting gas. The only limit to its lifespan in the Venusian atmosphere would be its power source and since it could take advantage of the freely available sun a platform like VAMP could run for an incredibly long time.

The concept is actually a rework of another one that was designed to fly through the atmosphere of Saturn’s moon Titan, a mission many have wanted to undertake since the Huygens probe landed there a decade ago. The challenges of flying an aircraft there are far greater than that of Venus, primarily due to the much thinner atmosphere and huge drop in solar radiation to take advantage of. It would still be doable of course, however the mission profile you’d have to go with would have to be much less ambitious and the time frames much shorter. Still it surprises me that the concept didn’t go the other way around as putting balloons in Venus’ atmosphere has always been a concept that many wanted to explore.

Northrop Grumman appears to be quite serious about the VAMP project as they outlined many objectives they wanted to achieve for it back in 2013. I can’t seem to find much more on it unfortunately which means it’s likely still in the concept phase, hoping for a mission profile to come along that suits it. Considering how many incredible envelope pushing missions we’ve had of late I don’t think something like VAMP is too far out of left field, especially considering that it’s based on already proven technologies. Still it doesn’t seem like it will be too long before we have a plane soaring through another world’s atmosphere, another science fiction dream becoming a reality.

Pinnacle Rock Jelly Doughnut Mars

Mars’ Pinnacle Island Mystery Solved.

Whilst Mars might not be the most lively planet around, with any tectonic activity ceased since its core cooled and its atmosphere stripped by our sun, it’s by no means a dead planet. We’ve bore witness to many things that we didn’t initially expect to see like dust devils flitting across Mars’ vast plains to massive avalanches that sent plumes of dust billowing up into the martian atmosphere. Still these events aren’t particularly common and the rovers we’ve sent to explore our red sister don’t usually see drastic changes in their surrounding landscape. That was until very recently when a strange looking rock seemingly appeared out of no where, causing rampant speculation and excitement about its origins.

Pinnacle Rock Jelly Doughnut MarsThe rock itself is fairly interesting, being around 4cm wide and having what many have called a “jelly doughnut” like appearance thanks to its white crust containing a red centre. Further analysis just deepened the mystery as Pinnacle Island (as it was then dubbed) contained levels of sulphur and manganese far above that of any other rock formation previously analysed from Mars. Such composition suggests that this rock formed in the presence of water, adding fuel to the theory that Mars was once not unlike Earth, but its uniqueness didn’t help in identifying where it had come from and thus the theories began rolling in.

Many initially postulated that it was an ejecta from a nearby asteroid strike, something that would be very likely to dig up unusual specimens like this and land them at our feet. Unfortunately since this was the only potential piece of ejecta found anywhere nearby this was unlikely as something like that would have created much more debris than just a single rock. Most of the other explanations devolved into conspiracy theories and crazy talk although I will admit that it was entertaining to think that aliens would mess with us by placing single rocks in front of our rovers. Now, after many months of speculation, NASA has announced the source of the mysterious rock and it’s as intriguing as it is mundane.

In short Opportunity created it.

The before and after pictures that made the rounds on the Internet are actually from 2 different cameras. The first is from the high resolution, typically forward facing, camera responsible for most of the beautiful images we see beamed back. The after picture is from a reward facing camera which was taken a couple days after Opportunity had passed by that particular location. Between those two pictures Opportunity actually ran over a small rock, crushing it into pieces and sending this one fragment rolling down the hill it was climbing up. This gave rise to Pinnacle Island and it’s former compatriot Stuart Island both of which can bee seen a mere 3 feet from each other.

This was always going to be the most plausible explanation (anything else would’ve been a little too fantastical) but it was great to see the wider world captivated by this scientific mystery, even if the speculation got a little bit crazy at times. Whilst it won’t lead to any major scientific revelations or brilliant insights into Mars it did serve as a good exercise in figuring out the origin of strange happenings, even if the origin turns out to be us.

 

DARPA XS-1 Concept

DARPA’s XS-1: Round 2 on the Space Shuttle Design.

On paper the Space Shuttle was the signal of the new space age where access to the final frontier would be cheap and reliable, ushering in the next wave of human prosperity. It would do this through two innovative (at the time) ideas: make the craft reusable and reduce the turn around time on launches to a mere 2 weeks, enabling 26 flights per year at a drastically lower cost than any other launch system. Unfortunately due to the requirements placed on it by the numerous different agencies that had their hand in designing it the final incarnation could not meet the latter goal and thus failed to provide the cheap access to space that it dreamed of. Of course it also taught us a lot about spacecraft design most notably that giant space planes aren’t particularly efficient ways of getting payloads into orbit.

That doesn’t seem to stop people from designing more of them, however.

DARPA XS-1 Concept

 

DARPA recently announced that it was seeking designs for a revolutionary space vehicle, dubbed the XS-1, with the intention of drastically lowering the cost per kg to orbit for small sized payloads (up to about 2,000KG). The design requirements are fairly open with the only stipulations being that the main craft is a reusable, hypersonic vehicle with the payload achieving the desired orbit using a traditional rocket. This means that whilst the potential craft detailed in the artist’s impression above is a good indicator of what the XS-1 hopes to achieve the actual craft could end up being radically different, especially if any of the other companies currently playing in this field having anything to do with it.

The main goal of this program is to drastically reduce the cost to orbit for smaller payloads, almost by an order of magnitude if you compare it to traditional launch systems. This, in turn, would lead to a lot of missions that were otherwise infeasible to become a reality and whilst the initial applications are more than likely to be military in nature I’m sure any private contractor would ensure a dual use agreement for the bulk of the technology. The crux of the XS-1, at least in my opinion, is whether or not this is achievable in the time frames that have set out for the project, considering that the first launch is scheduled for 2017.

Taking the rule of 6 into account (Mach 6 at 60,000 feet is 6% of the energy required for orbital velocity) a craft with such a flight profile would need to make several strong technological advances in order to be able to fly. The only engines capable of achieving speeds above that (at the required price) are scramjets and the fastest we’ve ever managed to get one to fly was Mach 5.1 last year. That means there’s still a long way to go to get sustained flight out of a hypersonic, air-breathing engine and it’s questionable that anyone would be able to achieve it in that time frame. Indeed even Lockheed Martin, who recently announced the hypersonic SR-72, doesn’t believe they’ll get a prototype flying before 2023.

I’m a fan of the idea, and indeed if anyone can pull it off I’ll be wildly impressed, however the technology to support it is still in its infancy with the cutting edge being far away from viability. There are other ways of tackling it of course but I can’t really see any of them being done for the price that DARPA is asking. Indeed the cheapest fully rocket solution goes to SpaceX but it’s still double the asking price for less payload than what DARPA requires. In any case the designs will hopefully show some ingenuity and, if we’re lucky, 2017 will bring us another baby brother to the retired Space Shuttle.