The rise of affordable commercial space launch services, including those done by SpaceX on its Falcon 9 rocket, has democratized space – giving satellite operators, who previously could not afford it, access to spaceflight. However, it’s also created new requirements in space that a number of emerging companies are working hard to meet through the introduction of new on-orbit services and capabilities.

One of these new capabilities is on orbit transport.

“…on orbit transport refers to a substantial adjustment to the altitude at which a spacecraft is operating,” said Kevin Lausten, the President of satellite propulsion solution provider, Morpheus Space. “The whole notion of orbital transport systems is moving spacecraft between…different [orbits].“

But how, exactly, has the introduction of affordable commercial space launch created the demand or need for on orbit transport services? Ultimately, it’s a response to the increased traffic and density of spacecraft in some orbits, including LEO. It’s also a solution to a massive economic challenge that many satellite operators are facing.

The right vehicle for the job

According to the European Space Agency, there are hundreds of millions of pieces of space debris currently in orbit around the Earth. That doesn’t include the more than 11,000 satellites that are also in orbit. And both of those numbers are growing, with more satellites being launched, and more space debris being created. In fact, just a few weeks ago, Intelsat 33e broke up in GEO , creating as many as 500 new pieces of space debris.

The proliferation of space debris and the seemingly constant launch of new satellites has made every orbit more congested. On orbit transport can be a solution on both parts of the congestion equation – helping mitigate debris, while also helping satellite operators move spacecraft from areas of risk.

These are two use cases that John Rood, CEO of Momentus, a provider of on orbit transport services, sees for his company’s offerings. According to Rood, “The dramatic increase in the number of objects in space is creating a serious debris hazard. Cleaning up debris in space is very much like re-positioning active satellites, so with some small additional capabilities, transportation vehicles can also be debris cleanup vehicles, transporting debris to lower orbits where they will re-enter the atmosphere much more quickly.”

However, on orbit transport is not just about avoiding debris. It’s also about getting satellites launched into orbit aboard commercial space launch platforms to their final destination in a more expedient and cost-effective manner.

“In order to take advantage of the low launch costs associated with the larger reusable rockets…small satellites are launched on a single rocket to a single drop-off point in space. That drop-off may not be optimal for each of the passengers, so there’s a growing market for in-space re-location to custom orbits,” Rood explained. “[On orbit transport] allows a customer…to have their satellite transported from the location where a launch vehicle dispenses payloads in space to the orbit and inclination they need for their mission.”

This can enable smaller satellite owners and operators to launch satellites into orbits that may not have been economically feasible before.

“On orbit transportation allows satellite operators to move satellites to orbits and inclinations that aren’t served by ride-share launch vehicles at much lower cost than buying a dedicated launch on a small launch vehicle that may cost more than feasible under the business case of a small satellite operator,” said Rood.

However, it can also enable all satellite operators to generate more revenue from their satellites during the course of their lifetimes. Satellites have traditionally leveraged their own onboard propulsion systems to get from where their launch vehicles drop them off to their final orbit. However, this takes a significant amount of time and uses up precious fuel – shortening the life of the satellite. On orbit transport is an effective way to move satellites more quickly without cutting into their life expectancy. This means revenue from each satellite is generated sooner, and for longer.

“…instead of taking six months to complete an orbit adjustment using on-board electric propulsion, if an orbital transport vehicle (OTV) was used, transit time could be reduced to a matter of days or a few weeks,” Rood explained. “A satellite could arrive on station months earlier and generate months of revenue faster. This provides important benefits to satellite owners and operators.”

However, there is a reason why on orbit transport systems are emerging a decade after SpaceX started launching satellites. There were significant technological advancements needed for such delicate operations as on orbit transport.

Enabling delicate operations in orbits far from Earth

Satellites are inherently expensive to build and launch. Owners and operators are therefore wary of other spacecraft interacting with their satellites. This is just one hurdle that on orbit transport companies needed to overcome when bringing their services to market – equipping OTVs with the technologies and equipment necessary to safely and effectively move another spacecraft.

Technically, the satellites that are being moved do not require any special hardware or equipment to be relocated by an OTV. “Simple fiducial markings and simple grapple fixtures, such as a bar, make in-space movement of satellites much easier,” Rood explained.

But it takes two to tango, and building an OTV that could operate far from Earth and safely interact with another spacecraft is much more involved and complicated.

“Advancements in autonomous systems, machine vision and AI are all contributing to allow the use of lower cost sensors with more sophisticated software to safely perform rendezvous [operations],” Rood explained.

Autonomy is particularly important as these operations happen further away from Earth – where latency and other factors could impact the ability of operators on the ground to control rendezvous operations.

“Today, transport satellites are operated similarly to many other types of spacecraft – which is a blend of autonomous operation with inputs from ground operators,” said Rood. “Mission and flight path planning is largely still conducted on the ground. Operators then upload instructions to the satellite to execute the plan. From there, the satellites are often able to autonomously execute orbit change maneuvers and maintain systems without direct ground control.”

But what happens when ground control isn’t possible?

“[When] you’re closer to the surface of the Earth…the lag time is not as such that you need to have substantial autonomy built into the system,“ said Lausten. “…as you get further from Earth, more automation needs to be built into the system.”

However, as more on orbit transport operations are conducted, there is hope that even more of the process can be automated, making it possible to further reduce human oversight and interaction, and enable OTVs to operate even further from Earth.

“In-space rendezvous operations tend to be much more closely supervised by the ground, though even here, many of the rendezvous and docking steps are performed autonomously by the satellite,” said Rood. “As experience is gained for rendezvous operations, this will be further automated.”

A new (deeper) space economy

On orbit transport has the potential to make satellite companies more profitable and extend the life of satellites today, but it could also kickstart a new space economy in the future.

“…by orbital transport services becoming more available, it’s going to expand space,” said Lausten. “That might sound cliche, but they expand the reach of the human race into deeper parts of space in a more reasonable way.”

Part of that involves transporting satellites into further orbits than would be economically feasible with existing commercial space launch services. As Lausten explained, “[You won’t] require a multi-billion dollar NASA mission to get to a cislunar environment. [Instead], you may be able to leverage an on orbit transport service provider...”

Should satellites and other spacecraft more routinely travel beyond GEO into even further orbits, there will be new services needed to sustain and repair them – creating a new space economy with new opportunities for entrepreneurial satellite companies.

“This creates a demand for additional services to exist within those environments. Services like communications, refueling in space, on orbit servicing, and other services of that nature,” said Lausten. “It expands our opportunities in space, but it also creates a demand for certain infrastructure services to exist in places that they’re probably considered to be sparse right now. And that’s exciting.”

Explore More:

Podcast: Smallsat Mobility and Maneuvering for SDA in LEO with Morpheus

Connectivity, TT&C and the Growing Space Servicing Needs

Falling Debris and Near-Miss Collisions: Mitigating Risk in LEO