For the first time in over three years, SpaceX launched its Falcon Heavy megarocket from Cape Canaveral Tuesday morning on a secretive mission for the U.S. Space Force.

The launch comes amid heightened concerns for space-based international conflict after Russian officials issued veiled threats last week to take out Western satellites perceived to be playing a role in Ukraine’s defense against ongoing Russian military operations.

Where has the Falcon Heavy been hiding?

The SpaceX Falcon Heavy had perhaps the splashiest debut of any of the private company’s projects, thanks to a payload test launch in 2018 that vaulted a convertible Tesla Roadster into space. And, as if that weren’t enough fun, the car had a mannequin, dubbed Starman, at the wheel dressed in a newly designed spacesuit from the company.

The Falcon Heavy hoisted some more practical payloads in two launches in 2019 but the powerful, heavy-lift vehicle has been idled since the smaller and more cost efficient SpaceX workhorse rocket, the Falcon 9, has become the go-to for contract flights and SpaceX projects, like the Starlink internet satellite network. So far in 2022, the Falcon 9 has performed over 50 missions, including ferrying astronauts to the International Space Station, carrying Starlinks into orbit and powering government-funded space missions.

The Falcon Heavy is currently the most powerful rocket in operation, but it’s a benchmark that will be bested by NASA’s Space Launch System which is poised for another attempt at its first launch later this month.

So, what’s the super-secret Space Force payload?

Tuesday’s Falcon Heavy launch was a long-planned contract mission for Space Force overseen by the agency’s Space Systems Command division.

Few details of the mission, called USSF-44, have been publicly released but reports the Falcon Heavy’s payload launched on Tuesday included two satellites and a number of tiny “cubesats.”

Of the two main satellites that were lifted into high earth orbit, only one has been identified by name: TETRA-1, which was built by Millennium Space Systems, a Boeing subsidiary. According to the company’s website, “TETRA-1 is a microsatellite created for various prototype missions in and around geosynchronous earth orbit,” per Beyond that, little is available about TETRA-1 or its larger companion payload.

According to a description on its website, Space Systems Command “is responsible for developing, acquiring, equipping, fielding, and sustaining lethal and resilient space capabilities for warfighters. As part of fielding, the command will be responsible for launch operations, on-orbit checkout, developmental testing, sustainment and maintenance of military satellite constellations and other Department of Defense space systems.”

Could Russian threats lead to a first-ever space war?

Ukraine’s military relies heavily on Elon Musk’s SpaceX for broadband internet beamed from its low-earth orbiting Starlink satellite network, according to a report from Reuters. U.S. firms like Maxar are capturing images of the war from satellites in orbit. And tens of thousands of communications devices in Ukraine rely on U.S. satellite communications giant Iridium’s satellite network, per Reuters.

Konstantin Vorontsov, a senior official in Russia’s Foreign Ministry, said last Wednesday that if U.S. satellites were used to aid Kyiv, they “could be a legitimate target for a retaliatory strike” according to The Wall Street Journal.

“We would like to emphasize the extremely dangerous trend that goes beyond the harmless use of space technologies, which clearly manifested itself in the course of events in Ukraine,” Vorontsov told a meeting of the First Committee of the United Nations General Assembly, according to remarks published by the Foreign Ministry, per the Wall Street Journal. “We are talking about the use by the United States and its allies of civilian infrastructure components in space, including commercial ones, in armed conflicts.”

Russia has proved its ability to target satellites using ground-launched missiles including in an exercise conducted last year that obliterated a defunct Russian satellite used as a test target.

“It’s really irresponsible to talk about shooting anything down in space for any reason,” Iridium chief executive Matt Desch told Reuters. “Space has gotten to be quite messy.”

“If somebody starts shooting satellites in space, I’d imagine it would quickly make space unusable,” Desch said.

White House spokesman John Kirby said last Thursday that any attack on U.S. infrastructure would be met with a response, but he did not go into detail.

“The legal aspects of all this are really murky at the moment,” Brian Weeden, a space policy analyst at the Secure World Foundation, told The Wall Street Journal. “We don’t have any examples of wartime uses of force against satellites — there’s really nothing to go off of.”

Other experts have noted that it would be extremely difficult to take out satellite operations by simply targeting one or two satellites, since most of the systems rely on networks of spacecraft. The SpaceX Starlink system, for example, now numbers around 3,000 satellites.