The X-37B is much smaller than the shuttle (it was originally intended to fit in the shuttle's payload bay). It physically can't retrieve satellites of any significant size.
This may be changing with rapid extension of satellite size towards the small end of the spectrum. Small size is now significant.
For example, a radar imaging constellation might consist of multiple transmit/receive satellites, each of which could be quite small (say, 1 - 5 cu. ft.). The X37B could accommodate that - especially after it snipped the solar panels off.
Obviously total speculation, but it's the right size to be a flying speed-of-light weapon platform. USAF have been interested in such tech for a long time. Some fun links:
It seems small for any sort of directed energy weapon with a useful power output. There wouldn't be enough capacity for a big generator and heat radiators.
Right, short of a small reactor onboard, it seems unlikely to be able to store the energy or power densities required while in flight. Obviously there may be some unknown breakthrough that allows it...but I'm skeptical.
Only if they're in low enough orbits to make use of atmospheric drag. Such orbits decay quickly if the vehicle does not have boost capacity. Given the extremely long missions this thing flies - several missions over 700 days - it seems unlikely for it to make use of atmospheric drag. It might do so when in a highly elliptical orbit but even then it needs to perform a burn at apogee to keep it from re-entering before long.
Anybody really in the know is definitely not going to spill the beans. The payload is very small, the stated reasons it flew its missions are 'testbed' for various technologies. Which may well be all there is to it.
The links to the specific missions on the wikipedia page have some expert conjecture, based on observations by amateur skywatchers, so we have a good idea that it's being used to launch military surveillance and communications satellites, as well as being used to test new hardware. Which is all rather broad and generic, but if it were aliens, it's not like they'd tell us anyway.
Even if it were actually confirmed that OTV-1 launched a military surveillance satellite, we still wouldn't know how good it is at that other than some hard limits due to physics (mirror size and atmospheric interference).
One common theory is it's being used to do close-up inspections of other countries' satellites. Bonus points if you can attach a magnetic limpet mine to them for future usage.
I don't think anything particularly detectable; they're so outweighed by the planet they're orbiting that the barycenter doesn't move measurably.
(To be clear, I'd imagine they're only doing the inspection thing right now, but I do suspect they're at least tinkering with on-orbit capture, refueling, disabling etc. with an arm.)
Maybe. The mass of an explosive could be pretty small compared to the mass of a satellite. And even if you do notice that your (secret military) satellite is slightly heavier than the spec says, what would you do about it?
How expensive is it to attach a couple of space-rated external cameras to a modern satellite? This wouldn’t eliminate the threat but it would certainly remove the uncertainty. Presumably once you recognized the threat, then defending against it couldn’t be the hardest problem to solve.
It would not need to be very big mine though would it? A grenade would probably be just fine to eliminate the satellite from being useful. Something that small means it could carry a lot of ammo
> A grenade would probably be just fine to eliminate the satellite from being useful
Sure, but if You are lucky or smart enough, to use it close enough.
For example Soviet satellite-interceptors spent few years and made few attempts (each time with bigger explosive), before achieve enough cloud density .
