Posts Tagged‘reusable’

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.

crane-lifts-ixv-prototype

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.

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.

autonomous_spaceport_drone_ship

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.

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.

Single Stage to Orbit: The Model T of Space.

No matter which way you cut it space is still the playground of governments, large corporations and the worlds wealthy. The reasons behind this are obvious, the amount of effort required to get someone or something into space is enormous and past applications that result in either scientific or monetary gain there’s little interest to take the everyman up there. That has rapidly changed over the past few years with several companies now making serious investment in the private spaceflight sector. Now nearly anyone who wishes to make the journey out of Earth’s atmosphere can very well do so, a privilege that until today has been reserved for mere hundreds of people. Still we’re far off from space being just another part of everyday life like flying has become but that doesn’t mean the seeds of such things aren’t already taking hold. In fact I believe with the right investment we could well see the Model T Ford equivalent of space within the next few decades.

Right now all commercial and governmental space endeavours use some form of chemical rocket. They generate thrust by throwing their fuel out the back of them at extremely high speeds and whilst they’re by far the most energy efficient jet engines you can create they’re also one of the most fuel hungry and also require that the craft being propelled by them carry their oxidiser¹ with them. Putting this into perspective the Space Shuttle’s external tank (the giant rust coloured cylinder) carries around 6 times more oxidiser than it does fuel with it, to the tune of 630 tonnes. That’s about 30% of the total launch mass of a completed Space Shuttle launch system and this has caused many to look for alternatives that draw their oxidiser directly from the atmosphere, much like the engine in your car does today.

Most solutions I’ve seen that use the atmosphere to achieve orbital speeds rely on a technology called scramjets. From a design standpoint they look a lot simpler than it’s turbojet/turbofan predecessors as there’s no moving parts used to compress the air. Scramjets rely on extremely high speeds to do the compression for them, meaning that they can’t be operated at lower speeds, somewhere in the realm of Mach 6 for a pure scramjet design. This means that they need some kind of supplementary thrust for them to be able to function.

One such solution is a that of an aeropsike engine. Apart from looking like something straight out of science fiction aerospike engines differ from regular rocket engines in that they don’t use the traditional bell shaped exhaust nozzles that adorn nearly every rocket today. Instead they use a concave spike shape that in essence forms a bell with outside air pressure. This has the effect of levelling off the performance of the engine at all altitudes although they suffer at lower mach numbers due to the reduced pressure. Still they compliment scramjets quite well in that they can be used in both situations where the scramjet can’t function (vacuum and low speed) whilst still remaining more efficient than current rocket designs.

Both of these ideas have been proposed as base technologies that would be used in a single stage to orbit (SSTO) launch system. All orbital capable launch systems today are done in stages whereby part of the rocket is discarded when it is no longer required. The Space Shuttle for example is a two stage rocket shedding the SRBs whilst it is still within earth’s atmosphere. A SSTO solution would not shed any weight as it climbed its way into space and the main driver for doing so would be to make the craft fully reusable. As it stands right now there are no true reusable launch systems available as the only one that’s close (the Space Shuttle) requires a new tank and complete refurbishment between flights. A fully reusable craft has the potential to drastically reduce the cost and turnaround time of putting payloads into orbit, a kind of holy grail for space flight.

SSTO isn’t without its share of problems however. Due to the lack of staging any dead weight (like empty fuel tanks) are carried with you for the full duration of the flight. Nearly every SSTO design carries with it some form of traditional chemical rocket and that means that the oxidiser tanks can’t be elminated, even though they’re not required for the full flight. Additionally much of the technology that a SSTO solution relies on is either still highly experimental or has not yet entered into commercial use. This means anyone attempting to develop such a solution faces huge unknown risks and not many are willing to make that jump.

Despite all this there are those who are working on including these principals into up and coming designs. NASA recently announced a plan to develop a horizontal launcher that would use maglev based track to accelerate a scramjet plane up to the required mach number before launching it, after which it could launch small payloads into space:

As NASA studies possibilities for the next launcher to the stars, a team of engineers from Kennedy Space Center and several other field centers are looking for a system that turns a host of existing cutting-edge technologies into the next giant leap spaceward.

An early proposal has emerged that calls for a wedge-shaped aircraft with scramjets to be launched horizontally on an electrified track or gas-powered sled. The aircraft would fly up to Mach 10, using the scramjets and wings to lift it to the upper reaches of the atmosphere where a small payload canister or capsule similar to a rocket’s second stage would fire off the back of the aircraft and into orbit. The aircraft would come back and land on a runway by the launch site.

Such a system would significantly reduce the costs of getting payloads into orbit and would pave the way for larger vehicles for bigger payloads, like us humans. Whilst a fully working system is still a decade or so away it does show that there’s being work done to bring the cost of orbital transport down to more reasonable levels.

A SSTO system would be the beginnings of every sci-fi geek’s dream of being able to fly their own spaceship into space. The idea of making our spacecraft reusable is what will bring the costs down to levels that will make them commercially viable. After that point it’s a race to the bottom as to who can provide the spacecrafts for the cheapest and with several companies already competing in the sub-orbital space I know that competition would be fierce. We’re still a long way from seeing the first mass produced space craft but it no longer feels like a whimsical dream, more like an inevitability that will come to pass in our lifetimes. Doesn’t that just excite you? 😀

¹As any boy scout will tell you a fire needs 3 things to burn: fuel, oxygen and a spark. Rockets are basically giant flames and require oxygen to burn. Thus oxidiser just means oxygen which also lets rocket engines operate in a vacuum.