Monday, 18 October 2021

The Chinese space plane test of 16 July 2021: orbital, not suborbital?

click map to enlarge

In my previous post I debated at length a claim by the Financial Times on October 16 that China recently did a FOBS test. This claim seems to be currently disintegrating, as suspicion is rising (following rebuttal comments by a Chinese Government offcial) that it all seems to refer to a Chinese reusable Space Plane test flight on July 16 instead. A test flight which was already reported earlier and hence known.

At the time when that Chinese Space Plane test flight was reported in July, it was reported as having been suborbital. This was (I think) mostly based on the proximity of the reported launch site (Jiuquan) and landing site (Badanjilin Airport), which are only some 220 km apart (indicating a short suborbital "hop").

But I now think that judgement was in error

If the whole FOBS-story indeed actually refers to the July 16 test flight, then it seems that it was orbital, completing one revolution.

Indeed, upon looking into it and trying some orbital scenario's, I found that a launch from Jiuquan into a 41.07 degree inclined orbit would actually very well match with a landing at Badajilin Airport at the end of one full revolution. I have depicted the resulting trajectory in the map in top of this post.

So: FOBS or space plane? Jeffrey Lewis has a point when he tweets:

"China just used a rocket to put a space plane in orbit and the space plane glided back to earth. Orbital bombardment is the same concept, except you put a nuclear weapon on the glider and don’t bother with a landing gear." - Jeffrey Lewis

But then, Mark Gubrud is likely also right about design differences when he tweets that:

"A FOBS/hypersonic missile would be optimized differently from a space plane. The plane would be designed to slow as much as possible on reentry (hence the blunt design of the Shuttle). It would have landing gear. It would have a payload bay, instead of an integral warhead."

The trajectory of the July 16 space plane flight, if my interpretation is correct, is not very FOBS-like. But this was only a test flight. Jeffrey is right that a space plane or glider in principle is suited for a deorbit with something in it's cargo bay that can go BOOM. This is why some other nations look with suspicion at the US X-37B space plane, currently on its sixth mission.

About the airport at Badanjilin: it seems to have been constructed rather recently. It is not present in Google Earth imagery from as recent as 2016. The landing strip is some 2.4 km long, oriented northwest-southeast, azimuth 313-133 degrees, and located at 39.2264 N, 101.5477 E. Below is a Copernicus Sentinel 2A image of the airport taken on 31 July 2021 (note the Camel!):

click image to enlarge

UPDATE 18 Oct 2021 19:45 UT:

Something very confusing is that, while the Chinese Government now seems to suggest that the orbital flight reported on by the Financial Times in fact was this July 16 space plane flight, Chinese news items on this space plane flight from that time seem to state that the flight was "suborbital", as Jonathan McDowell has pointed out. 

Still, I am not convinced as the word is used several times in a context where it is odd (e.g. when describing the space plane as a technology). The same in an English language bulletin by Xinhua, which also talks about a "reusable suborbital carrier". That sounds more like an aircraft to me (perhaps one launched with a booster stage and then flying through the upper atmosphere), than a space plane. I have no knowledge of the Chinese language at all (the only thing I can say in Chinese is "thank you") so do not know what is possibly lost in translation here.

Even more confusingly, the first Chinese item linked above seems to name yet another airport (so another one than that pictured above) as the landing site:  Youqi airport. I found a Youqi airport which is near 48.5764 N, 116.9377 E. The runway of that airport however seems a bit short for a space plane landing. Jonathan McDowell  thinks I got the wrong Youqi and points out that the Badanjilin Airport imaged above is also called Youqi....oh well. He probably is right (he usually is). We can use some more confusion in this already confusing case...

Both with regard to "FOBS or not", and the July 16 "space plane", many things remain very ambiguous.

It could be that the Chinese Government is now seizing on the July 16 test to explain away a later FOBS test.

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