It’s strange, looking back over all my space posts of the past 3 years I couldn’t find any that were dedicated to the European Space Agency’s cargo craft, the Automated Transfer Vehicle. Sure I mentioned it in passing back when JAXA sent its first HTV to the International Space Station but even its second flight, named Johannes Kepler, obviously wasn’t inspiring enough for me to take notice. The only good reason I can come up with is the maiden voyage happened well before I got into blogging, but that doesn’t excuse me ignoring the significance of the ATV.
The ESA’s ATV is the only craft that the ESA has that participates in the ISS program. It’s a derivative of the Multi-Purpose Logistics Module that the Shuttle used to carry up to the ISS and is meant to work alongside the Russian Progress craft that have been resupplying the ISS for years. Compared the Progress its something of a monster being able to deliver almost 4 times the payload although that’s offset significantly by the fact that it’s current launch rate is about once per year. The majority of the payload is taken up by reboost and attitude control propellant as the ATV is capable of reboosting the ISS, something which no other craft is currently capable of doing (the retired Shuttle was the primary reboost craft prior to this). The rest of the payload consists of crew and station consumables, roughly equivalent to the amount that a Progress craft would deliver.
Today sees the ESA’s 3rd ATV docking with the International Space Station:
Whilst it’s not pushing any boundaries or developing new capabilities the successful docking of the Edoardo Amaldi shows that the ESA can make the yearly launches of the ATV without incident. That’s quite an achievement in itself and means that the 2 currently planned ATV launches should go off without a hitch. With the upcoming flights from companies like SpaceX and Orbital Sciences to the ISS you might be wondering why we’d bother having a craft like the ATV, especially when something like the Dragon has similar capabilities whilst also being reusable. The answer, from my perspective is two fold.
For starters neither of the upcoming private craft have the ability to reboost the ISS. Now doing this is non-trivial so its unlikely that either craft will gain that ability in the near term and as far as I can tell there are no other craft, current or planned, that have that ability. That surprises me as the second argument for the ATV’s existence, redundancy in capabilities, doesn’t exist with ISS reboosting. It’s possible that the upcoming Space Launch System with the Orion capsule might be able to do this but I can’t find anything that states that.
The second reason, as I alluded to before, is that when it comes to maintaining a human presence in space it doesn’t hurt to have redundancy for different capabilities. Whilst you can argue that there will be much better ways of doing things in the future it never hurts to have a backup that you can rely on. The ATV, with its rock solid yearly launch schedule, makes for a good fall back for other re-supply missions should they encounter any issues. Now all that’s required is finding another means by which to reboost the ISS and then we’ll have full redundancy across most of our manned space program activities.
4 days ago the Japanese Aerospace Exploration Agency (JAXA) launched the first flight ready version of their HII Transfer Vehicle (HTV) line. Whilst on the surface that might not sound like much it marks a significant step forward in Japan’s space capability, as up until now their involvement with the Internation Space Station only involved the Kibo laboratory, all of which was hoisted up by their American counter-parts. It’s quite an interesting craft due to the omission of certain things and the reason it was built. Before I get into that however here’s a bit of eye candy showing it’s rendezous with the International Space Station:http://www.youtube.com/watch?v=115pSsW9aXU
Apart from the amazing view of earth that this video shows it also demonstrates one of the oddities of the craft. Now the HTV isn’t the first of this kind of spacecraft to visit the ISS. The most frequent visitor is the Russian Progress craft, which has been responsible for delivering the majority of supplies to the space station. It’s basically a Soyuz craft minus all the gear to support a crew replaced with cargo storage, as it was impractical for the Soyuz craft to be used for both crew and cargo (it is quite small after all). The other is the European Space Agency’s Automated Transfer Vehicle (ATV) which made its madon voyage to the ISS in March last year. What separates these from the HTV is that they both have an automated docking capability allowing them to hook up to the space station with no involvement from the ISS crew. That’s why you see the CANADARM2 stretching out to grab it. You’re probably wondering then, why the heck do we need another cargo ship to supply the ISS and beyond?
The HTV is something of a special purpose craft. Whilst its payload capacity is less than that of the ATV it does sport a much larger docking portal. That by itself doesn’t sound like much but the ATV can’t carry the Interational Standard Payload Racks because of this limitation. The only other way of getting these things inside the ISS is through Multi-Purpose Logistic Modules which fly with the space shuttle, something which is scheduled to stop happening in the near future. In essence the craft is a cheaper alternative to getting standard cargo payloads up to the station once the shuttle is retired, which is a good niche for JAXA to fill.
It might not be the most sexy or exciting craft around but the more countries that develop a capability like this means a lot to humanity at large. We’re starting to see a critical mass developing in both the public and private sector space industries and for a space nut like myself it provides many an hour of slack jawed reading and gazing. Japan’s fresh view on how to get cargo into space is an idea that not many have considered in the past and I hope they continue their involvement past this endeavour.
Big thumbs up to you guys 🙂