Zuma, The Phantom Satellite

It was January 8, 2018, a clear night at Cape Canaveral. The SpaceX Falcon 9 rocket launched beautifully, casting a brilliant light over the dark marshes. Minutes later the spent first stage separated and fell away, and the second stage burst into life and sped the craft even higher, aiming for whatever orbit the payload would eventually assume. The payload fairings detached and tumbled away as planned once the craft was out of the atmosphere, and the secretive satellite known only as Zuma was exposed to space. As it rocketed higher and higher, still attached to the SpaceX second stage, the media broadcasts cut off for secrecy purposes. All we know about what happened next is a series of seemingly contradictory events that guaranteed Zuma will inspire lively debate to both space historians and conspiracy theorists alike for quite some time. Today we're going to point the skeptical eye at what's known, what's rumored, and some really cool stuff that might be true — and that would also be unprecedented.

Everything about this launch was weird, even before it happened, prompting space enthusiasts to pay extra close attention. Unconfirmed reports were published online (before the launch) that SpaceX boss Elon Musk:

...sent an email about this launch stating that it was the most valuable satellite they have launched to date. Any misgivings or inklings of issues... call or email him directly and he would get teams on it to verify.

The hazard areas published in advance of the launch — warning of the places to avoid should the rocket fail soon after launch, and then again where the spent second stage was expected to fall — told us that Zuma's orbit was to be at a 50°-51° inclination. Picture a hula hoop around the Earth, but tilted 50° off horizontal. This is a virtually unheard of orbit. Optical spy satellites are at sun-synchronous 98° polar orbits; electronic intelligence (SIGINT) satellites use highly elliptical 63.4° orbits; radar satellites use a 68°, 57°, or 123° orbit; and geostationary orbits launch at a 28° inclination. The only other launch at 50° was only eight months earlier, an equally secret satellite designated USA-276 launched by the National Reconnaissance Office — a spy satellite. USA-276 is very close to the International Space Station's orbit. So close, in fact, that just a month after its launch it passed only 6.4 kilometers from the station — that's wildly, insanely close. Early speculation was that Zuma, with its similar inclination, might have had some similar intent; but as we'll see, that turned out not to be the case.

Also strange was that nobody claimed the satellite. All the government agencies that launch satellites denied Zuma was theirs, and all those with launch schedules have no gaps in their numbering into which Zuma might fit. We honestly have no idea whose it might be, beyond it being some agency of the United States government.

One final piece of weirdness perked up ears throughout the space community. Zuma was built for its mysterious customer by Northrop Grumman, there's no secret about that. Like all satellites, it was attached to the top of the rocket with a component called the payload adapter. Usually (but not always) these are provided by the booster manufacturer, in this case SpaceX. But this one was provided by Northrop Grumman itself. The payload adapter is responsible for the actual separation, when the satellite is released onto its own, and the booster then de-orbits to burn up in the atmosphere. This particular adapter was subjected to an unusually high number of ground tests for the separation procedure — three. The reason Northrop Grumman gave for this — to be taken with a grain of salt — is that the separation required unprecedented delicacy, suggesting a fragility of the payload greater than any previously launched satellites.

Let's get back to the launch itself — we last left our intrepid spacecraft shedding its payload fairing, and the cameras cutting off. The plan from this point was anybody's guess, known only to those with sufficient clearance. But in any launch, the next step would have to be for Zuma to disconnect from that payload adapter once it reached its orbit, and for the now-independent second stage to perform a final de-orbit burn. Exactly when all this happened depended on how high Zuma's orbit was to be, how much longer it would need elevating thrust from the booster — it could have been seconds later, or hours later. Instead, what happened was that news outlets all reported the launch had been a failure. Something failed and Zuma had not separated from the second stage, and both fell back into the atmosphere and were destroyed.

And that's only if you believe the news. Which, in the case of a classified launch like this, consists only of whatever is released by those who actually know. They can say whatever they want, and the media has no way to fact check it.

This leaves us at a bit of a disadvantage, since the best we can do is "informed speculation" about a mission that remains both current and classified. The best information on Zuma is out there and known, but not to us. As our friendly neighborhood aerospace journalist Jeff Foust said to me in reference to Zuma, "Those who talk don't know, and those who know don't talk."

But the world of amateur space enthusiasts is not without resources of its own. The key piece of information came from Peter Horstink, the Dutch pilot of a Martinair 747 freighter aircraft en route from Amsterdam to Johannesburg, about two and a quarter hours after the launch. His photograph — now widely available on the web — shows a bright blue-green spiral in the sky above Sudan, the second stage beginning its de-orbit burn. Horstink recorded its elevation and azimuth, allowing amateur satellite trackers to make a pretty good calculation of Zuma's altitude: between 900 and 1,000 km. (Remember that altitude.) Although on the same inclination as USA-276, Zuma was aiming for a far higher orbit than its predecessor, hundreds of kilometers too high to approach the ISS as USA-276 did.

But of interest were the arms of the spiral that Horstink photographed. They consisted of vented propellant, which is always done before dropping a vehicle into the atmosphere in order to avoid crashing a fueled rocket into someone's house. The spirals showed that it was spinning or tumbling, which is not correct.

Briefly, the news was full of a blame game between SpaceX and Northrop Grumman, each saying the other was responsible for the failure. But soon SpaceX was cleared. If anything had failed it would have been Northrop Grumman's payload adapter. SpaceX's launch schedule with other customers continued undelayed, proving to all parties that no fault was detected in SpaceX's equipment.

We're left with two basic possibilities for what happened to Zuma:

1. The planned separation failed as advertised, and Zuma remained attached to the booster. This caused the booster's mass and center of mass to be wrong when it made its de-orbit burn, resulting in the tumbling and spirals. Both burned up on re-entry.
   
   
2. The failure was a cover story for launch that actually succeeded — a cover story complete with an orchestrated public dispute between SpaceX and Northrop Grumman. It's hard to get classified payloads into unusual orbits without anyone seeing it these days, given the skills of the amateur space tracking community — some 18,000 observations of 200 classified satellites were recorded on the SeeSat-L email list in just one year alone. They're a formidable force. A claimed failure may have been to discourage the amateurs from looking for Zuma — lotsa luck, if that was the plan.

Like all successful government-owned satellites, Zuma has been given an official designation by the US Air Force: USA-280. This has prompted some to claim that it must therefore still be active. However, all that's required for such a designation to be given is that the spacecraft complete one orbit; and Zuma required almost one and a half orbits just to climb to the altitude where Horstink saw it venting propellant. So the fact that Zuma was given an active satellite designation doesn't mean that it was successful, and doesn't tell us anything we don't know.

So far there have been no amateur sightings of anything on Zuma's orbit, consistent with it having failed as advertised. So, if anything's up there (and that's still a big "if"), it isn't easy to spot. The unique, extra-gentle payload adapter mechanism tells us that this thing was probably weird. Combine weird with hard to spot and we may have a stealth satellite, and this is not a new concept. Beginning in 1990, the MISTY stealth satellite technology demonstrators were launched. MISTY-1 was USA-53, launched from the space shuttle in 1990 — perhaps as gentle a release as Northrop Grumman sought to achieve for Zuma — and it flew for at least seven years. Interestingly, it was announced that MISTY-1 exploded six days after launch, and at that same moment, it became invisible to observers. In fact what happened is that it had deployed a cone-shaped balloon of synthetic polymer film coated with gold or aluminum to reflect radiation. The cone was pointed straight down at the Earth, reflecting radar signals off into space, and also reflecting only the darkness of space down to the telescopes of hopeful amateur observers — we have these details because the contractor Teledyne Industries actually filed a patent for it. MISTY re-appeared at least once when it made some maneuvers, proving for a certainty that its "explosion" had been a false cover story. If you were skeptical about the possibility of Zuma's separation failure being a smokescreen, chew on the MISTY story.

The Internet's community of amateur satellite trackers eventually gave us what appears to be virtually an open-and-shut case for the most likely purpose of Zuma. It was discovered in Russian space blogs by an anonymous tracker in Hong Kong who goes by Cosmic Penguin, and reported by Marco Langbroek. The Russian amateurs had dug up a 2007 report from the US Congressional Budget Office titled Alternatives for Military Space Radar which discussed potential satellite constellations that would provide synthetic aperture radar (SAR) observation combined with ground moving target indication (GMTI). Basically, these satellite systems would provide real-time, theater-wide battlefield data, including continuous coverage of selected targets. The kicker? All four options would require the satellites to be in 1,000-km high circular orbits, at an inclination of 53° — nearly exactly where Zuma was headed.

With sufficiently reasonable certainty, Zuma is (or was) a prototype of an all-new line of tactical military satellites. If it is up there, the lack of observations tells us that the stealth capability has been improved; MISTY suffered from reflections of sunlight, which nobody has seen yet from Zuma.

Of course, Zuma may have just gone down in flames on that dark night over Africa. There are people who know; but as we noted, those who know don't talk.

Update: In May 2021, the US Space Force declassified its new program to do satellite-based GMTI. Still no proof linking this to Zuma, but all the pieces fit perfectly. —BD

By Brian Dunning
Follow @BrianDunning