Fast or thrifty: a wave of money is reshaping how satellites move

A wave of military money and dealmaking is reshaping a corner of the space business most people never see. It is the small engines that let a satellite move once it is already in orbit [1]. National-security customers want spacecraft that can dart to a new spot quickly and still keep maneuvering for years [1]. Those two demands pull against each other, and the whole market is now organised around the gap between them [1].

The tradeoff underneath

The tension is simple physics. A chemical engine shoves hard and can change a spacecraft’s speed fast, but it burns propellant at a high rate [1]. An electric engine ionizes a gas and flings the charged particles out the back. It is far more efficient, wringing more speed from each gram of propellant, but it pushes gently and takes far longer to finish the same maneuver [1]. You get quick, or you get thrifty. Getting both in one vehicle is the prize everyone is now chasing [1].

Money is picking sides

The buying tells the story. York Space Systems acquired Orbion Space Technology, a Michigan maker of Hall-effect thrusters, a common kind of electric engine [1]. Voyager Technologies acquired ExoTerra Resource, a Colorado electric-propulsion firm [1]. Quantum Space is building a spacecraft, Ranger, that runs one propellant through both a chemical and an electric mode [1]. An operator can then switch between fast and efficient as the mission demands.

At the strong-but-thirsty end, Rubicon Space Systems finished hot-fire testing its Velox thruster, a five-newton engine burning a low-toxicity fuel meant to replace hydrazine [2]. It is moving into production for flights in 2027 [2]. Five newtons is roughly the push of a full glass of water resting in your hand: modest, but instant [2]. The Space Force also disclosed a toaster-sized hybrid from Parabilis, built to give cubesats more thrust than an electric system without the plumbing of a full liquid engine [1].

The thriftiest engine has no fuel tank

At the far efficient extreme sits a Spanish startup, Kreios Space, which announced on Aug. 4 the first planned flight of a satellite carrying no fuel tank at all [3]. Its air-breathing electric thruster scoops the thin gas at the edge of the atmosphere. It ionizes the oxygen and nitrogen, then throws it out the back for a tiny amount of thrust [3]. The craft will fly at about 200 kilometers up, in a band called very low Earth orbit [4]. Down there a normal satellite drags and burns up within weeks unless it pushes constantly [4]. Sharing a NanoAvionics microsatellite bus, it will test the thruster and shoot sub-meter images [4].

Why the patience pays off

The slowness of electric propulsion has already rescued a mission. When the main chemical engine on the U.S. military’s AEHF-1 communications satellite failed after launch, controllers used its small Hall thrusters to spiral it up to the right orbit over more than a year [5]. Gentle, but it got there. That heritage now belongs to Rocketdyne, which re-emerged this month as a standalone company [5]. It has delivered about 22,000 chemical thrusters and flown more than 500 of its RL10 upper-stage engines [5]. Europe’s SMART-1 probe made the same trade a generation ago, spiraling to the Moon on an ion engine over sixteen months [6]. Apollo made that trip in three days on chemical power.

The launch calendar behind it

The propulsion push rides on a busy launch schedule. Chinese company Landspace planned an Aug. 10 attempt to launch and land its reusable Zhuque-3 rocket, a methane-powered vehicle in the class of SpaceX’s Falcon 9 [7]. SpaceX flew its 90th Falcon 9 of the year in early August [8], and told investors it hopes to launch its giant Starship again this month [11]. Rocket Lab lofted a Japanese Earth-observing satellite after a five-week delay [10]. Not everything went smoothly. Blue Origin traced the explosion of its New Glenn rocket to a failed valve in an engine [9]. Chemical power, for all its punch, has more to go wrong.

Why it reaches you

These small engines are why a weather satellite holds its station, a spy craft can dodge, and a probe can reach Jupiter. Orbit is filling with satellites that must move to survive: dodging debris, changing position, fighting drag [1]. For them the choice between a hard shove and a patient push stops being a detail and becomes the mission. Increasingly the plan is to let the spacecraft itself decide which to use, moment to moment [12].