Posts Tagged‘space shuttle’

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.

Space Shuttle Atlantis: Down But Not Out.

Late last night space shuttle Atlantis streaked across the night sky in a brilliant blaze of firey glory on its way back down to earth. After writing about the mission just over a week ago I’d been dreading this moment for quite some time as it meant that it would be the first shuttle to enter official retirement. Still we can’t dwell on the negatives for too long as space shuttle Atlantis has served humanity well running 32 missions, travelling over 180 million kilometers and spending a total of 282 days in space. So what else is there to say about the first of our iconic spacecraft to hit retirement? Well there is the fact that it might not be its last flight at all.

Readers of this blog will more than likely remember me detailing some of the standard operating procedures of a shuttle flight. One of those is that should the shuttle sustain enough damage to make returning to earth too risky they must have somewhere to stay whilst a rescue mission is planned. Traditionally they can take refuge as the ISS as it is more than capable of handling the extra load for a month or so whilst they roll out another shuttle. Now this doesn’t mean that NASA can just whip up an entire shuttle mission within a month, far from it. In fact all rescue missions are planned well in advance with many of the critical components ready to go, including things like the external fuel tank and SRBs. For our soon to be retired friend Atlantis this means that whilst it’s completed its final official mission, its job is far from over.

STS-134 is the last planned flight for any space shuttle and that means should Endeavour not be able to return to earth the astronauts will be trapped at the ISS. Whilst we could ferry them down in Soyuz craft it would take an extremely long time and would tax the resources of both Russia and the USA considerably. As such they’ve designated a special Launch on Need (LON) mission called STS-335 that will be launched to rescue them should Endeavour be stranded in space. This mission has Atlantis as the designated craft for the mission and this has lead to an interesting proposition:

“We need to go through the normal de-servicing steps, obviously, after the orbiter comes home…We have to prepare Atlantis and the stack as if we’re going to fly again because it is (launch-on-need) mission,” said shuttle launch director Mike Leinbach.

“We’ll be processing her as if it’s a real flight to begin with. Somewhere along the line we expect to hear whether we’re going to launch or not, and at that point in time either press on or stop that processing. But in order to support that, obviously, we have press on when she gets home.”

But with long odds that a rescue would really be required, there’s a notion to fly Atlantis crewed by just four astronauts on a regular mission and a large logistics module to service the International Space Station with supplies and more science equipment.

Designing such a mission, getting the cargo pulled together and training a crew would take many months, so the clock is ticking for a “go” or “no go” decision.

In essence we’d have a shuttle that was fully flight ready, all it would be missing is a payload. The crew would intentionally be kept small in order to ensure that in the event of an emergency they could all return aboard the attached Soyuz craft, which would also limit what kind of payload you could send up there. Still having a shuttle tricked out and ready to fly is not something you’ll have the opportunity to do again and this is what has got tongues wagging about whether or not NASA should in fact fly Atlantis one last time.

There’s no denying that any flight into space has an enormous amount of value. Whilst every precaution is taken to ensure that the ISS has everything it needs there’s no harm in bringing up extras for it. Even with the reduced crew there’s still the opportunity to fly up some additional hardware like some of cancelled ISS modules (a few of which were partially built). Still if such a mission were to go it would more than likely be a strict logistics mission as anything else would require extensive amounts of planning, something that I’m not quite sure congress would be willing to approve (flying Atlantis just for logistics would be costly enough).

So whilst the great Atlantis might have been the first to return to earth on its final official flight there’s still a chance that we’ll see this bird fly once again. I might lament the fact if it does ever fly (making my trip to the US to see the last shuttle flight moot) it would still make my heart soar to see it lifting into the sky one more time. Such is the awesome beauty that is the space shuttle.

STS-130: Endeavour’s Brilliant Radiance.

16 hours ago space Shuttle Endeavour lifted off on its mission STS-130. The image above was captured barely a minute after take off as Endeavour passed through the thin clouds that remained after the previous launch attempt was scrubbed yesterday. This gave rise to the picture you see above and it is truly breathtaking. As with all recent Shuttle missions the event was also heavily televised as seen below (skip to 10:48 for the good bit):

Watching this video I can’t help but feel awe at the shear magnitude of power being unleashed by our triumph of science. For what seems like an eternity Endeavour shines brighter than any light and then turns into a bright star before slowly fading from our view. There’s a kind of magestic beauty seeing something so large and powerful moving so gracefully as to almost qualify itself as art. If I hadn’t planned already to see the very last of the Shuttle launches ever this one would’ve been next on my list, as for a thing of beauty nothing can quite match a night launch in my books.

In the midst of all this awe and wonder there’s still a lot of good old fashioned space work behind this launch. STS-130 brings to a close the last of the major construction work (more on that in a minute) that will be done on the International Space Station. The Tranquility module contains the most advanced life support equipment to date with facilities to recycle waste water, generate air for the astronauts to breathe as well as removing any contanimates that might taint the environment.  Whilst not as spacious as the Japanese Kibo module its no small fry and will primarily be used for storage, exercise and accessing the Cupola. The main function of the Cupola will be to facilitate robotics work that will be done on the ISS using the various arms they have installed there. Additionally it also contains the largest window ever flown into space and it will be installed facing Earth. Although its not the main reason for its existance you can bet that the astronauts on board will be chomping at the bit to get some view time through that portal. I know I would.

If you watched the video above you may have noticed a little information widget on the left hand side detailing some interesting information about the Shuttle during its launch. One of them which may look a little odd (especially if you’ve got an engineering bent) is the SSME Thrust percentage which hovers above 100% for the majority of lift off. Now this might seem strange since no system is capable at operating above 100% but there’s a good reason for this. The Space Shuttle Main Engine was initially designed with a certain amount of thrust in mind and was tested successfully to that specification. However further testing showed that the engine was quite capable of running safely beyond its design, all the way up to 109% of the required thrust. This has then become the norm for all launches with the higher power levels saved for contingency operations should they be required. It really shows how talented the NASA engineers are.

There’s still a day and half to go before they actually meet up with the ISS and the majority of that time will be spent getting the Shuttle ready to dock and ensuring that the Shuttle hasn’t suffered any damage on the way up. After that they’ll do their signature backflip and take their mission into full swing. There’s a busy 2 weeks ahead for all these astronauts.

STS-130’s launch was one of beauty and its fitting that it will bring to the ISS a portal with which the astronauts can look back at us as we look up at them. Whilst I feel a twinge of sadness knowing that there are only 4 more launches left before the magestic shuttle never flies again I can also take heart in the fact that soon a new era of space will be heralded in by a new vision for NASA. Times like these remind me how far we’ve come, and how bright our future is.