The SR-71, commonly referred to as the Blackbird, was a pinnacle of engineering. Released back in 1966 it was capable of cruising at Mach 3.2 at incredible heights, all the way up to 25KM above the Earth’s surface. It was the only craft that had the capability to outrun any missiles thrown at it and it’s for this reason alone that not one Blackbird was ever lost to enemy action (although a dozen did fail in a variety of other scenarios). However the advent of modern surveillance techniques, such as the introduction of high resolution spy satellites and unmanned drones made the capabilities that the Blackbird offered somewhat redundant and it was finally retired from service back in 1998. Still plane enthusiasts like myself have always wondered if there would ever be a successor craft as nothing has come close to matching the Blackbird’s raw speed.
The rumours of a successor started spreading over 3 decades ago when it was speculated that the USA, specifically Lockheed Martin, had the capability to build a Mach 5 version of the Blackbird. It was called Project Aurora by the public and there have been numerous sightings attributed to the project over the years as well as a lot of sonic boom data gathered by various agencies pointing towards a hypersonic craft flying in certain areas. However nothing concrete was ever established and it appear that should the USA be working on a Blackbird successor it was keeping it under tight wraps, not wanting a single detail of it to escape. A recent announcement however points to the Aurora being just a rumour with the Blackbirds successor being a new hypersonic craft called the SR-72.
Whilst just a concept at this stage, with the first scaled prototype due in 2023, the SR-72’s capabilities are set to eclipse that of the venerable Blackbird significantly. The target cruise speed for the craft is a whopping Mach 6, double that of its predecessor. The technology to support this kind of speed is still highly experimental to the point where most of the craft built to get to those kinds of speeds (in air) have all ended rather catastrophically. Indeed switching between traditional jet engines and the high speed scramjets is still an unsolved problem (all those previous scramjet examples were rocket powered) and is likely the reason for the SR-72’s long production schedule.
What’s particularly interesting about the SR-72 though is the fact that Lockheed Martin is actually considering building it as the aforementioned reasons for the Blackbird’s retirement haven’t gone away. Whilst this current concept design seems to lend itself to a high speed reconnaissance drone (I can’t find any direct mention of it being manned and there’s no visible windows on the craft), something which does fit into the USA’s current vision for their military capabilities, it’s still a rather expensive way of doing reconnaissance. However the SR-72 will apparently have a strike capable variant, something which the Blackbird did not have. I can’t myself foresee a reason for having such a high speed craft to do bombing runs (isn’t that what we have missiles for?) but then again I’m not an expert on military strategy so there’s probably something I’m missing there.
As a technology geek though the prospect of seeing a successor to the SR-72 makes me giddy with excitement as the developments required to make it a reality would mean the validation of a whole bunch of tech that could provide huge benefits to the rest of the world. Whilst I’m sure the trickle down wouldn’t happen for another decade or so after the SR-72’s debut you can rest assured that once scramjet technology has been made feasible it’ll find its way into other aircraft meaning super fast air travel for plebs like us. Plus there will also be all the demonstrations and air shows for Lockheed Martin to show off its new toy, something which I’m definitely looking forward to.
The USA has always been wary of China’s ambitions in space and I believe it’s mostly for all the wrong reasons. Sure I can understand that the fact that China’s space division is basically a wing of its military might be cause for concern, but the same could be said for the fact that the USA’s Department of Defense’s budget for space exploration exceeds that of NASA’s. Indeed the USA is worried enough about China’s growing power in space and other industries that there’s already been speculation that it could spark another space race. Whilst this would be amazing for a space nut like myself I really wouldn’t wish that kind of tension on the world, especially when the USA is struggling as much as it is right now.
Of course that tension is enough to spark all sorts of other speculation, like for instance the true nature of the mysterious X-37B’s mission. It’s payload bay suggested that it was capable of satellite capture, an attribute shared by it’s bigger cousin the Shuttle, but its previous orbits didn’t put it near anything and it didn’t really have enough delta-v capability to be able to intersect with anything outside a few degrees of its own orbit. However since then there’s been a couple launches and one of them is smack bang in the X-37B’s territory.
The craft in question is none other than China’s Tiangong-1.
Yesterday the BBC ran an article that speculated that the USA was using the X-37B to spy on Tiangong-1. Now initially I dismissed this as pure speculation, there are far easier ways for the USA to spy on a satellite (like using one of their numerous other satellites or ground based dish arrays) than throwing their still experimental craft up in a chase orbit. However checking the orbital information for both Tiangong-1 and the X-37B shows that they do indeed share very similar orbits, varying by only 0.3 of a degree in inclination and having pretty similar apogees and perigees. Figuring this is the future and everything should be a few Google searches away from certainty I set about finding out just how far apart these two satellites actually are to see if there was some possibility of it being used to spy on China.
To do this I used 2 different tools, the first being n2yo.com a satellite tracking website. This site allows you to input the satellites you want to track and then displays them on a Google map. Once I have that I can then use another tool, this time from findpostcode.com.au which shows me the distance between two points (which thankfully also takes into account the fact the earth isn’t flat). So firstly here’s a picture of the two orbits overlapped:
So as you can see they do indeed share very similar orbits but there does seem to be an awful lot of distance between them. Just how much distance? Well the second picture tells the full story:
Just over 14,000KM which is greater than the diameter of the earth. What this means is that if the X-37B was being used to spy on Tiangong-1 it would have to peer through the earth in order to see it, something which I’m pretty sure it isn’t capable of. Also if you look at the first picture you’ll also notice that Tiangong-1 actually passes over the USA as part of its normal orbital rotation, putting it well within the purview of all the ground observations that they have control of. I’ll note that the distance between Tiangong-1 and the X-37B won’t remain constant, but they will spend a good portion of their lives apart. Enough so that I don’t believe it would be particularly useful for reconnaissance. Additionally unless the USA knew which orbit that Tiangong-1 was going to use (possible, but we’re getting deeper into conspiracy territory here) then technically Tiangong-1 launched onto the X-37B’s orbit and not the other way around (it has not changed its orbit since the second launch, unlike it did the first time).
Honestly the idea that the USA was using the X-37B was definitely an interesting prospect but in reality there’s really no justification apart from conspiracy theory-esque hand waving. The USA has far better tools at their disposal to spy on China’s fledgling space industry than a single run experimental craft that’s only on its second flight. The orbits also put them at a fair distance apart for a good chunk of the time (as far as I can tell, at least) as well making it even less likely that the X-37B is being used for spying. Still it was an interesting idea to investigate, as is most things to do with the ever mysterious X-37B.
Maybe it’s the combination of mission secrecy and close resemblance to the now retired shuttle fleet but the X-37B seems to get more press than any other space craft currently flying in orbit. When I first saw the diminutive shuttle cousin back in April last year I figured it was just a unique experiment that the Department of Defence was carrying out and the rumours about it’s satellite capturing capabilities were greatly exaggerated. Indeed towards the end of the mission I investigated the idea that it was already performing such a task but based on the current trajectories of other satellites it didn’t seem like that was the case. The X-37B blasted off once again at the start of this year again shrouded in mystery as to what its actual mission was and it’s been up there ever since.
That last fact is interesting as the X-37B’s stated capabilities put it at being on-orbit for a maximum of 270 days. The deadline for its return to earth would have then been around November 30th, a date that has well past now. The United States Air Force has stated that its mission has been extended and it should be on orbit for a while to come. This is interesting because it tells us that the X-37B is a lot more capable than they’ve state it is. Whilst this could just be good old fashioned American over-engineering it does lead some credence to the theories that there’s a whole bunch of capabilities hidden within the X-37B that aren’t officially there.
What’s been really interesting however are the discussions surrounding a potential manned variant of the X-37B. As it stands the X-37B is quite a small craft, measuring a mere 10 meters long and a payload bay that’s only got a few cubic meters of storage space. Overall its very similar in size to the Soyuz craft so there’s definitely some potential for it to be converted. Rumour has it that the X-37B would be elongated significantly though, bringing its total length up to 14 metres with enough space to sit 7 astronauts. Granted it wouldn’t be as roomy as the shuttle was (nor could it deliver non-crew payloads at the same time) but it would be a quick path to restoring the USA’s manned flight capability. That would hinge on the man rating Atlas V launch system which is currently under investigation.
It’s not just space nuts that are getting all aflutter about the X-37B either. China has expressed concerns that the X-37B could be used as a orbital weapons delivery system. The secrecy surrounding the actual mission profiles that the X-37B has been flying is probably what has prompted these concerns and it being under the sole purview of the Air Force doesn’t help matters. In all honesty I doubt the X-37B would be used as a weapons platform since it’s more of a generalist/reconnaissance craft than a weapons platform. If there’s someone you want to worry about launching weapons into orbit it would be the Russians as they are the only (confirmed) nation to have launched armed craft. A dedicated weapons platform would also look nothing like the X-37B, especially if it was going to be designed for on-orbit combat (who needs wings in space?).
The next couple months will give us some more insight as to the true purpose of the X-37B. It’s quite likely that these first couple flights have just been complete shake downs of all the systems that make up the X-37B with the first flight being orbital manoeuvring verification and the current flight being an endurance test. Should it stay up there for a significant amount of time it’s more likely that it’s some form of advanced reconnaissance craft rather than something crazy like a satellite capturer or orbital weapons platform. The prospect of a manned variant is quite exciting and I’ll be waiting anxiously to see if the USA pursues that as an option.