A computer-generated image representing space debris as could be seen from high Earth orbit. The two main debris fields are the ring of objects in geosynchronous Earth orbit and the cloud of objects in low Earth orbit. (Image via NASA)
Space is getting crowded. Aging satellites and space debris crowd low-Earth orbit, and launching new satellites adds to the collision risk. The most effective way to solve the space junk problem, according to a new study, is not to capture debris or听deorbit听old satellites: it鈥檚 an international agreement to charge operators 鈥渙rbital-use fees鈥� for every satellite put into orbit.听
Orbital use fees would also increase the long-run value of the space industry, said economist Matthew Burgess, a听. By reducing future satellite and debris collision risk, an annual fee rising to about $235,000 per satellite would quadruple the value of the satellite industry by 2040, he and his colleagues concluded in a paper published today in the听.
鈥淪pace is a common resource, but companies aren鈥檛 accounting for the cost their satellites impose on other operators when they decide whether or not to launch,鈥� said Burgess, who is also an assistant professor in environmental studies and an affiliated baby直播app member in baby直播apps at CU Boulder. 鈥淲e need a policy that lets satellite operators directly factor in the costs their launches impose on other operators.鈥�
Currently, an estimated 20,000 objects鈥攊ncluding satellites and space debris鈥攁re crowding low-Earth orbit. It鈥檚 the latest tragedy of the commons, the researchers said: Each operator launches more and more satellites until their听private听collision risk equals the value of the orbiting satellite.听
So far, proposed solutions have been primarily technological or managerial, said听Akhil听Rao, assistant professor of baby直播apps at Middlebury College and the paper鈥檚 lead author. Technological fixes include removing space debris from orbit with nets, harpoons, or lasers.听Deorbiting听a satellite at the end of its life is a managerial fix.
Ultimately, engineering or managerial solutions like these won鈥檛 solve the debris problem because they don鈥檛 change the incentives for operators. For example, removing space debris might motivate operators to launch more satellites鈥攆urther crowding low-Earth orbit, increasing collision risk, and raising costs.听
鈥淭his is an incentive problem more than an engineering problem. What鈥檚 key is getting the incentives right,鈥� Rao said.听
A better approach to the space debris problem, Rao and his colleagues found, is to implement an orbital-use fee鈥攁 tax on orbiting satellites.听
鈥淭hat鈥檚 not the same as a launch fee,鈥� Rao said, 鈥淟aunch fees by themselves can鈥檛 induce operators to听deorbit听their satellites when necessary, and it's not the launch but the orbiting satellite that causes the damage.鈥澨�
Orbital-use fees could be straight-up fees or听tradeable听permits, and they could also be orbit-specific, since satellites in different orbits produce varying collision risks. Most important, the fee for each satellite would be calculated to reflect the cost to the industry of putting another satellite into orbit, including projected current and future costs of additional collision risk and space debris production鈥攃osts operators don鈥檛 currently factor into their launches.听
鈥淚n our model, what matters is that satellite operators are paying the cost of the collision risk imposed on other operators,鈥澨齭aid Daniel听Kaffine, professor of baby直播apps and听RASEI听Fellow at CU Boulder and co-author on the paper.听
And those fees would increase over time, to account for the rising value of cleaner orbits. In the researchers鈥� model, the optimal fee would rise at a rate of 14 percent per year, reaching roughly $235,000 per satellite-year by 2040.
For an orbital-use fee approach to work, the researchers found, all countries launching satellites would need to participate鈥攖hat's about a dozen that launch satellites on their own launch vehicles and more than 30 that own satellites. In addition, each country would need to听charge the same fee per unit of collision risk for each satellite that goes into orbit, although each country could collect revenue separately. Countries use similar approaches already in carbon taxes and fisheries management.
In this study, Rao and his colleagues compared orbital-use fees to business as usual (that is, open access to space) and to technological fixes such as removing space debris.听They found that orbital use fees forced operators to directly weigh the expected lifetime value of their satellites against the cost to industry of putting another satellite into orbit and creating additional risk. In other scenarios, operators still had incentive to race into space, hoping to extract听some听value before it got too crowded.听
With orbital-use fees, the long-run value of the satellite industry would increase from around $600 billion under the business-as-usual scenario to around $3 trillion, researchers found. The increase in value comes from reducing collisions and collision-related costs, such as launching replacement satellites.
Orbital-use fees could also help satellite operators get ahead of the space junk problem. 鈥淚n other sectors, addressing the tragedy of the commons has often been a game of catch-up with substantial social costs. But the relatively young space industry can avoid these costs before they escalate,鈥� Burgess said.
