Many people awaited last Sunday’s Falcon 9 launch from Cape Canaveral of a highly classified US payload. The launch had been delayed for weeks, speculation as to the satellite’s purpose was rampant, and successfully delivering national security satellites to orbit is an important part of SpaceX’s business.
The launch, however, remains shrouded in mystery.
Shortly after the launch, Bloomberg reported that the satellite was lost, due to US Strategic Command saying they were not tracking any objects. The Wall Street Journal suggested that Congress was being briefed on a failure, and that it was due to a failure of the satellite to separate from the final stage, and so both were deorbited together.
A Verge story notes that neither SpaceX (the launcher) nor Northrup Grumman (the contractor who built the satellite) declared that the mission was a success after launch. SpaceX’s president said that the Falcon 9 “did everything correctly” and that they did not have a failure that requires investigation. Northrup Grumman stated that it does not comment on classified missions. Northrup Grumman provided the equipment that connects the satellite to the final rocket stage and that is eventually meant to separate them. So SpaceX’s claim that nothing went wrong with its end could be still be consistent with an overall failed mission.
What could the Zuma satellite be?
The Zuma satellite (USA280) is curious. It’s a classified satellite and so there’s no public description of its purpose. Satellite watchers usually pick up some clues about the purpose of a classified satellite by who made it and what orbit it is put in. For example, spy satellites that are imaging the ground in visible light often use sun synchronous orbits (close to a polar orbit) so that they can see the earth at a constant sun angle, which is helpful in detecting changes. Signals intelligence satellites tend to be at around 63 degrees inclination (the angle the orbit makes with respect to the equator).
Because there was no pre-launch announcement of orbital parameters, nor does the Space Track catalog provide them (it never does for such classified missions), we don’t know what orbit it was meant to go in exactly, but you can tell the approximate inclination by where the hazard zones are from its launch.
Marco Langbroek created this image of the Zuma launch hazard zone (in red in Fig. 1) for his blog:
This indicates that the satellite was launched in an orbit that was inclined around 50 degrees to the equator, similar to the International Space Station. Not many satellites use low earth orbits with 50 degree inclinations, except for satellites that were launched from the space station and so end up there. (See for yourself by sorting the satellites in the UCS Satellite Database.)
One other recent classified satellite, USA 276, was launched in that type of orbit, and it was launched in a similar direction as Zuma. That satellite was launched not only in the same orbital inclination as the ISS but also the same orbital plane. It was subsequently observed by the amateur observing community as having made a close approach to the ISS when it was performing docking maneuvers. Marco has a fascinating analysis in The Space Review about it.
What happened to it?
Zuma (USA 280) is still listed as a payload on orbit by the US space surveillance system (Fig. 2), as of this writing (January 12). So something made it into orbit and went around at least once. The object is listed as a payload and not as launch debris, indicating it is the satellite.
Marco’s blog also reports sighting of the re-entry of an object that seems to square with the predicted time for the (intentional) de-orbit of the Falcon 9’s final stage, so that appears to no longer be in space. This is consistent with the successful placing into orbit of the satellite and the disposal of the last stage. (That’s good space “hygiene.”)
So there are a few possibilities:
- The Zuma satellite failed to separate from the final stage, and returned to earth along with the final stage and no satellite is in orbit. If this is the case, eventually the Space Track catalog will be updated and USA 280 will be removed. But this seems unlikely, since the satellite is still catalogued as being in orbit four days after launch.
- The satellite is in orbit. Indications this is the case would be that it remains in the catalog, and that amateur observers on the ground get a view of it. These observers use binoculars and telescopes to see satellites in reflected sunlight, and they are quite skilled at hunting satellites. However, they won’t get a chance to weigh in for a couple of weeks as the satellite won’t be optically visible in the regions of the northern hemisphere where most of them are. It’s possible that in the interim, the satellite will maneuver to another orbit, so finding it after a couple of weeks will be difficult.
Whether the satellite is functioning as intended would be difficult to tell, at least at first. If satellite watchers manage to see it and determine its orbital parameters over a period of time, they may be able to see whether it performs any maneuvers. An on-orbit maneuver is a positive sign that the satellite is at least alive, although doesn’t say whether it’s performing as designed. The lack of such maneuvers, especially if the satellite is in a relatively low orbit and would ordinarily need to compensate for atmospheric drag, can indicate that it is not functioning. Radars should be able to track the satellite, so presumably countries with space surveillance-capable radars, such as China and Russia, know quite a bit more about this already.
- While there is some precedent for using a launch failure as a cover story for a stealthy satellite (Misty), it’s hard to keep a satellite reliably hidden. (Note that the US has much more invested in space surveillance than other actors, so this would be even more difficult for countries other than the US.)
There are things that you can do to make it harder to see a satellite. You can minimize its radar reflectivity so that Russian and Chinese radars would have a harder time seeing it. You can minimize how reflective it is in the sunlight so that ground-based optical observers would have a hard time seeing it, too. Or you might make the satellite’s orbit unpredictable by maneuvering, so trackers must perform a time-consuming search for it each time they want to see it.
You’d probably need to do all these things at the same time to have hope of being stealthy for a significant period of time, and these techniques put a lot of constraints on the satellite itself. And one cannot credibly hope to stay stealthy indefinitely.
What’s curious about Zuma is that the bits of information don’t yet add up to a coherent story. There’s more information to come which may help—stay tuned!