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.
Studying 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.
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.
The 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.
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 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.
Do you remember the Microwave Power Plant in Sim City 2000? The idea behind them was an intriguing one, you launched a satellite into orbit with a massive solar array attached and then beamed the power back down to Earth using microwaves that were collected at a giant receiver. Whilst it worked great most of the time there was always the risk that the beam would stray from its target and begin setting fire to your town indiscriminately, something which the then 11 year old me thought was particularly hilarious. Whilst we’ve yet to see that idea (or the disasters that came along with it, but more on that in a moment) the idea of putting massive solar arrays in orbit, or on a nearby heavenly body, are attractive enough to have warranted significant study.
The one limiting factor of most satellite based designs though is that they can’t produce power constantly due to them getting occluded for almost half their orbital period by Earth. Shimizu Corporation’s idea solves this issue in the most fantastical way possible: by wrapping our moon in a wide band of solar panels, enabling it to generate power constantly and beam it back down to Earth. Such an endeavour would seem like so much vapourware coming from anyone else but Shimizu is one of Japan’s leading architectural and engineering firms with annual sales of $14 billion. If there’s anyone who could make this happen it’s them and it aligns with some of the more aggressive goals for space that the Japanese government has heavily invested in of late.
The idea is actually quite similar to that of its incarnation in Sim City. Since the Moon is tidally locked with Earth (I.E. one side of the moon always points towards us) there only needs to be a single base station on the moon. Then a ring of solar panels would then be constructed all the way around the Moon, ensuring that no matter what the position of Moon, Earth and the Sun there will always be an illuminated section. There would have to be multiple base stations on Earth to receive the constantly transmitted power but since the power beams would be pointable they needn’t be placed in any particular location.
Of course such an idea begs the question as to what would happen should the beam be misaligned or temporarily swing out of alignment, potentially roasting anything in the nearby vicinity. For microwaves this isn’t much of a threat since the amount of power delivered per square meter is relatively low with a concentrated burst of 2 seconds barely enough to raise your body temperature by a couple degrees. A deliberately mistargeted beam could do some damage if left unchecked but you could also combat it very easily by just putting up reflectors or the rectilinear antennas to absorb it. The laser beams on the other hand are designed to be “high density” so you’d want some rigorous safety systems in place to make sure they didn’t stray far from the course.
Undertaking such a feat would require several leaps in technology, not least of which would be in the automation of its construction, but it’s all based on sound scientific principles. It’s unlikely that we’ll even see the beginnings of something like this within the next couple decades but as our demand for power grows options like this start to look a lot more viable. I hope Shimizu pursues the idea further as they definitely have the resources and know how to make it happen, it’s all a question of desire and commitment to the idea.
Ever since getting things into orbit became a routine task the amount of stuff we’ve left floating around us in space has increased exponentially. Typically the debris that surround us are made up of the upper stages of rockets, disused satellites that can’t/won’t de-orbit for some time and, worst of all, innumerable other bits of miscellanea that are the result of things crashing into each other. This is the beginnings of a terrible self inflicted disease called Kessler Syndrome whereby the lower orbits are so littered with junk that launching anything becomes nigh on impossible, save for some drastic changes in technology. Thus it’s in our best interests to come up with some workable solutions to this issue and the engineers at the Japanese Aerospace Exploration Agency (JAXA) have come up with a very interesting solution.
Whilst most of the debris surrounding Earth will eventually make its way back down the time frame in which it will do so varies from years to centuries. Since the orbits are unstable it’s likely that they’ll change drastically over time and this means that the chance that they will collide with another bit of debris increases quite dramatically. This is the real crux of the issue as collisions of this nature create much more debris than their individual parts alone (it is also why all the collective space faring nations were a rather pissed at China for testing their anti-satellite missile). Whilst there’s not much we can do for the numerous small bits of debris orbiting Earth there’s a lot we can do for a specific type of space junk, specifically the upper stages of rockets, and this is what JAXA’s latest development targets.
The team at JAXA’s Innovative Technology Research Center have devised what they’re calling an electrodynamic tether to help combat the space debris issue. It consists of a small space craft, one could imagine something of cubesat size, that attaches to a large piece of debris via a long electrically conductive tether. Then, by virtue of the fact that Earth has a magnetic field and the tether is conductive, Lorentz forces then act to drag the two satellites back down to Earth. It’s a rather ingenious way of getting the junk to deorbit as it doesn’t rely on carrying massive amounts of propellant, making the craft infinitely smaller and far more efficient. It might only tackle a specific subset of the debris in space but their calculations show that this should be enough to prevent a runaway Kessler syndrome situation.
Probably the coolest thing about it, at least for me, was the preferred way of attaching the tether to the target. They have explored some regular options, namely coasting up to the craft and attaching it with a robotic arm, but since their targets are going to be the usually thin walled upper stages of craft they’re instead opting for a harpoon that will penetrate the hull of the craft. So in the future we could have a swarm of harpoon carrying cubesats orbiting us, ensuring that any large bit of space junk is brought to the fiery demise it so rightly deserves.
Of course this doesn’t mean the problem is completely solved but this could be enough of a stop gap solution whilst we figure out better ways of cleaning up our lower orbits. It’s not going to be an easy problem to solve, the energies required to get everything up there in the first place ensure that, but things like this show that there are highly efficient ways of dealing with it. All that’s required is for us to find them and, hopefully, deploy them before its too late.
Whenever the idea of establishing a colony off-world comes to mind the first place many think of is Mars. Primarily this is due to Mars being the most similar of all the other planets to ours, having an atmosphere and land features that look very similar to some of our own. However that’s where the likeness ends as its lack of magnetic field has meant that its atmosphere has been stripped bar to a thin layer of carbon dioxide, taking all of the surface water along with it. Thus whilst it would seem like the best candidate for humans to establish themselves elsewhere in this solar system there are other potential sites that have distinct advantages over what Mars can provide.
One surprisingly good candidate for a potential human colony is Mercury. Now initially this would seem like a pretty bad idea as its surface temperatures regularly exceed several hundred degrees celsius and the only atmosphere to speak of is a tenuous layer is mostly made up of solar wind and vaporized surface material. However it’s close proximity to the sun gives it access to abundant solar power, orders of magnitude more than what is available on the surface of Mars. Considering that power is probably one of the biggest limiting factors for a colony and the size it can grow this advantage could prove invaluable, so long as the initial challenges could be overcome.
Probably the biggest thing that Mercury has going against it is the time it would take to get a mission there. Whilst we’ve got craft today capable of covering the distance in under 40 days or so its tight orbit around our sun makes it incredibly difficult to get into orbit with it. It’s not so much that it’s hard to do, more that the time typically required to transit to there with an approach that will get you into orbit takes on the order of years, not days. This would mean the development of systems to support humans for a sustained period in space which would open up other alternative locations for a human colony.
Interestingly such systems could be used to establish a colony on Venus, although not the type you’d think of. Whilst Venus’ surface is a hellish place where it rains metal it would be quite possible to create cloud cities that float around an area that’s much more hospitable to humans. Indeed the pressure at 50KM above the surface is the same as Earths and thanks to the dense, mostly carbon dioxide atmosphere a lifting gas that’s simply breathing air has a lifting power of 50 times that of helium on earth. The protections required then are far less strenuous than those required to get to Mercury initially and the dangers posed by the atmosphere are far less severe than that of a harsh vacuum.
Past these planets though are options start to get limited as whilst many moons of the gas giants of the outer solar system have an abundance of things like water or other useful materials they’re typically quite harsh environments, either being flooded with ionizing radiation or lacking any kind of atmosphere without the benefit of having high amounts of light to take advantage of. They’re essentially equivalent to space itself in that regard and whilst I love the idea of large human colonies in space there’s really no substitute for colonizing another planet.
For what its worth we’re likely going to see a Mars colony within our lifetimes, one that will likely be limited to a few one way pioneers or entrepreneurs looking to take advantage of the first new frontier in a century. The other options, whilst being only slightly more fantastical than that of a Mars colony, aren’t likely to happen any time soon as there needs to be much more ground broken in engineering terms before they become viable. Regardless of where it happens a human colony off our planet is fast becoming a necessity if we want to ensure the human race doesn’t have a single point of failure in our own planet.
For a country that was barred from ever working with the leader in space technology the progress China has made in the last decade has been incredibly impressive. They’ve quickly gone from humble beginnings in 2003 where their first taikonaut made it into orbit to a fully fledged space station in 2013, showing that they have the technical expertise required to consistently attempt envelope pushing activities. Of course whilst the most interesting aspect of any space program is the manned activities (who doesn’t love seeing people in space!) there’s always the quiet sibling in the robotics departments, attempting missions that few humans will be able to attempt. I must admit that until today I was also ignorant of China’s robotic efforts in space but suffice to say they’re just as impressive as their human based accomplishments.
China’s Chang’e program (the name of the Chinese Goddess of the Moon) is a series of lunar spacecraft tasked with creating highly detailed maps and models of the Moon’s surface with the intent that that data will be used for future manned missions. Chang’e 1 was launched back in 2007 and remained in lunar orbit for 2 years. It created the most accurate and detailed sufrace map of the moon to date and, once it was done, plummeted into the surface it just mapped to send up a spray of regolith that could be studied from here on Earth. It’s successor, Chang’e 2, was launched in 2010 and had similar capability (albeit with higher resolution instruments and a lower orbit) but instead of being plunged into the moon at the end of its mission it was instead sent out to do a flyby of asteroid 4179 Toutatis. Its current trajectory will eventually see it hit interstellar space however its likely it’ll run out of fuel long before that happens and the purpose of the extend mission is to validate China’s Deep Space Tracking network.
Chang’e 3, launched just yesterday, will be the first craft China has ever launched that will land on the Moon’s surface. For a first attempt it’s a fairly ambitious little project consisting of both a lander and a rover, whereas similar missions usually go for a lander first prior to attempting a rover. The lander is an interesting piece of equipment as it contains a RTG as a power source as well as an ultra-violet telescope, making it the first luna based observatory. Whilst it won’t be anything like the Hubble or similar space telescopes it will still be able to do some solid science thanks to its location and it makes the lander’s useful life much longer than it typically would be.
The rover is just as interesting, being roughly equivalent to the Mars Exploration Rovers (Spirit and Opportunity) in terms of size and weight. It can provide real time video back to Earth and has sample analysis tools on board. The most important instrument it carriers however is a radar on its base allowing it to probe the lunar surface in a level of detail that hasn’t been done before, giving us insights into the make up of the regolith and the crust beneath it. It will be interesting to see what its longevity will be like as its power source is its solar panels (unlike its parent lander) and the lack of atmosphere should mean they’ll remain clean for the forseeable future.
As of right now there’s another 2 more missions in the Chang’e line both of which have similar capabilities with the exception of Chang’e 5 which will be a lunar sample return mission. After that it’s expected that China will start to eye off manned lunar missions, starting with the traditional flag planting operations and then quickly escalating to a fully fledged moon base not long after. It’s quite possible that they’ll accomplish that within the next 2 decades as well as their past accomplishments show how quickly they can churn out envelope pushing missions, something that other space fairing nations have been lacking as of late.
Whilst it might not be of the same heights we saw during the cold war there’s definitely another space race starting to heat up, although this time it’s between the private space industry and China. Whilst it’s likely that China will win the race to the Moon and possibly Mars I can’t help but feel that the private industry isn’t too far behind. Heck, combine Bigelow Aerospace and SpaceX and you’ve already got the majority of the Chinese manned program right there! Still this does not detract from the accomplishments the Chinese have made and I only hope that eventually the USA changes its stance on co-operating with them.
The Kepler Mission is by far one of the most exciting things NASA has done in recent memory. It’s goal was simple, observe a patch of stars continuously for a long period of time in order to detect the planets that orbit them. It’s lone instrument for doing so is a highly sensitive photometer designed to detect the ever so subtle changes in brightness of a parent star when one of its planets transits in front of it. Whilst the chances are low of everything lining up just right so that we can witness such an event the fact that Kepler could monitor some 145,000 stars at once meant that we were almost guaranteed to see a great deal of success.
Indeed we got just that.
The first six weeks of Kepler’s operation proved to be highly successful with 5 planets discovered, albeit ones that would likely be inhospitable due to their close proximity to their parent stars. The years since then have proved to be equally fruitful with Kepler identifying thousands of potential exoplanet candidates with hundreds of them since being confirmed via other methods. These discoveries have reshaped our idea of what our universe looks like with a planetary system like our own now thought to be a relatively common occurrence. Whilst we’re still a long way from finding our home away from home there’s a ton of tantalizing evidence suggesting that such places are numerous with untold numbers of them right in our own galaxy.
However earlier this year Kepler was struck with an insurmountable problem. You see in order to monitor that field of stars precisely Kepler relied on a set of reaction wheels to ensure it was pointed in the right direction at all times. There are a total of 4 of them on board and Kepler only needed 3 of them in order to keep the precision up at the required level. Unfortunately it had previously had one fail forcing the backup wheel to kick into motion. Whilst that had been running fine for a while on May 15th this year another reaction wheel failed and Kepler was unable to maintain its fix on the star field. At the time this was thought to be the end of the mission and, due to the specialized nature of the hardware, likely the end of Kepler’s useful life.
However, thanks to some incredibly clever mechanics, Kepler may rise again.
Whilst there are only 2 functioning reaction wheels NASA scientists have determined that there’s another source of force for them to use. If they orient Kepler in a certain way so that its solar panels are all evenly lit by the sun (the panels wrap around the outer shell of the craft) there’s a constant and reliable force applied to them. In conjunction with the 2 remaining reaction wheels this is enough to aim it, albeit at a different patch of the sky than originally intended. Additionally it won’t be able to keep itself on point consistently like it did previously, needing to reorient itself every 3 months or so which means it will end up studying a different part of the sky.
Whilst this is a massive deviation from its original intended purpose it could potentially breathe a whole new life into the craft, prolonging its life significantly. Considering the numerous discoveries it has already helped us achieve continuing its mission in any way possible is a huge boon to the science community and a testament to NASA’s engineering prowess. We’re still at the initial stages of verifying whether or not this will work as intended but I’m very confident it will, meaning we’ll be enjoying Kepler aided discoveries for a long time to come.
Mars is by far the most studied planet that isn’t our own, having had 46 separate missions launched to it since the 1960s and is currently host to no less than 5 active missions both in orbit and on its surface. Those missions have taught us a lot about our red celestial sister, the most intriguing of which is that it was once not unlike Earth, covered in vast swaths of ocean which could potentially have been host to all sorts of life. Even more interesting is that while it’s little more than a barren desert that’s only notionally above vacuum it still contains water ice in non-trivial quantities, leading many to speculate that somewhere its liquid form must also exist. The process by which Mars transformed from a lush landscape like ours to the wasteland it is today is still shrouded in mystery and is something that MAVEN, NASA’s latest mission to Mars, is seeking to solve.
MAVEN successfully launched yesterday atop of an ATLAS V rocket and will spend the better part of a year transiting the distance between Earth and Mars. Its primary objective is to investigate the evolution of Mars’ atmosphere to try and ascertain the factors that influenced its demise. Since the current prevailing theory is that a cooling planetary core led to a loss of a protective magnetic field which then allowed the solar wind to slow strip away the atmosphere many of the instruments aboard the craft are geared towards measuring solar particles around Mars’ orbit. The rest of the instrumentation is focused on directly measuring Mars’ atmosphere which will then allow scientists to reconstruct a full picture of it and the influences working on it.
I believe this is also (and someone feel free to correct me on this) the reason for its slightly abnormal orbit for when it arrives at Mars. Instead of taking the usual approach of having a near circular orbit (like the Mars Reconnaissance Orbiter) it instead has a highly elliptical orbit with the closet approach being a mere 150KM above the surface whilst its furthest point is 6200KM out. This would allow the craft to get good measurements of the levels of solar particles as it gets closer to the surface and how that compares to it further out. Considering the orbital period will also only be 4.5 hours it would make for some rather exciting flybys if you were aboard that craft but then again that’s not an orbit you’d use if you had people on board.
The orbit also has the rather unfortunate effect of limiting one of MAVEN’s more long term capabilities: it’s link back to Earth. MAVEN has a 10Mbit/s link thanks to an updated Electra array which is almost twice as powerful as MRO’s. However due to the rather eccentric orbit it won’t be available as often which will limit the amount of data that can be passed back. This doesn’t just impact the satellite itself though as whilst the rovers on Mars can communicate directly to Earth it’s not a very fast connection, so most offload onto a local satellite for their more data hungry applications. Since it’s currently only an augment to the other fleet of satellites around Mars this isn’t too much of an issue although it could present some contention issues later on the track when the other satellites are retired.
The science that MAVEN will conduct on its planned 1 year mission will prove invaluable in determining just what happened to Mars’ atmosphere and, by extension, what the chances are of any life existing on its surface today. It will also provide infrastructure for future missions, allowing them to be more ambitious in the goals that they attempt to reach. For now though it’s 1 day into its long trip to our celestial sister, quietly awaiting the day when it can finally start fulfilling its purpose.
The International Space Station hasn’t really been struggling since the retirement of the Shuttle with it still being able to maintain its full 6 person crew even with the significantly reduced launch capacity. Indeed the bevy of alternative craft that have been visiting the ISS, such as the SpaceX Dragon and the Orbital Sciences Cygnus, have meant that it’s also been well supplied in the absence of a largo cargo tug like the Shuttle. Still there is no current replacement for getting humans up there with that responsibility falling solely to the Russian Soyuz craft although NASA is funding some alternatives. I’ve covered most of them in the past but one of the main contenders, Sierra Nevada Corporation’s Dream Chaser, just passed a significant milestone, albeit with a few issues.
Their craft bears a striking resemblance to the Shuttle, sporting the same thermal tile underside and similar aerodynamic profile. It’s quite a bit smaller than the Shuttle however, being about a quarter of the length and a seventh of the mass, mostly due to its lack of payload bay. It can still carry up a comparable number of astronauts however, up to 7 in its current configuration which is only 1 shy of the Shuttle’s maximum. The design is also quite interesting as whilst it looks like any other space plane it is in fact a lifting body with those wings being on there for control purposes only.
Lifting bodies are an interesting type of craft whereby the craft’s design makes it one giant aerofoil, eliminating the need for big wings in order to generate lift. Indeed NASA has quite a history with lifting body craft having designed and built at least 3 of them in the past. The idea was solid enough for it even to be considered as one of the alternative designs for the Space Shuttle itself although the other requirements (primarily from the Department of Defense) meant that it wasn’t used in the end. Dream Chaser’s design then uses the lifting body for simplicity and efficiency, allowing for their smaller craft to do the one task of ferrying humans into orbit well without any of the additional cruft that plagued the Shuttle.
Dream Chaser recently underwent its first unmanned drop test to confirm its flight characteristics and to give all of its systems their first shakedown. For the most part the mission was a success with the lifting body performing as expected and the remote control systems functioning perfectly. However upon landing the left landing gear failed to deploy causing the craft to spin uncontrollably when the left wing contacted the run way. It’s eerily similar to the landing skid failure that SpaceShipOne encountered during one of its shakedown flights, although that one had a person inside it at the time (he was unscathed, however). It’s not a show stopping issue but it will probably mean furthering testing will be delayed until they can figure out why it happened, and make repairs to their prototype.
For what its worth I think the future of space travel will be in craft like Dream Chaser, ones that favour simplicity and efficiency over trying to make a multi-purpose craft. Indeed all the current contenders in the private space industry are doing just that, building craft with a specific purpose in mind and ensuring they do it efficiently. Whilst this first drop test might have had some hiccups it’s shown that the lifting body idea is aerodynamically sound and that there’s no fundamental flaws in their idea. Once they’ve worked out that landing gear kink I’m sure we’ll see dozens of successful drop tests to follow and, hopefully, some fully powered tests in the not too distant future.