Air Traffic Management magazine recently spoke with Cranfield University regarding the topic of traffic management for upper airspace. The industry expects substantial growth of traffic at these levels and today there isn’t a consistent strategy for managing traffic traveling to and within the upper levels. Professor Stephen Hobbs (SH) , Professor of Space Sensing and Systems and Dr Dimitri Panagiotakopoulos (DP), Head of Advanced Air Mobility Research Group shared their thoughts.
Q - As traffic increases in the upper airspace due to commercial space flights, what do you see as the main challenge of managing this traffic?
SH: For commercial space flight, it depends on the type of mission. Sub-orbital (horizontal launch, e.g. space tourism) likely to return to same airport and only to reach around 100 km, is suitable for national management; the challenge is that a large region may need to be cleared, and on an irregular basis (launches depend on suitable weather and on customer demand). Sub-orbital (vertical launch, e.g. sounding rockets), is likely to be a small market (science, some technology demonstration). Orbital: Launch (vertical launch and eventual re-entry or recovery) has to be integrated into the airspace management, but we are still far from having practical space traffic management. A challenge would be due to the cadence of launches needed for some of the mega-constellations now planned.
DP: ATM will play a key role in order to seamlessly and safely integrate routine commercial space flights (CSF) into existing airspace, particularly during the launch and re-entry phases. ATM will have to be able to integrate a variety of commercial space vehicle (SV) types and accommodate a number of space port (SP) operations. The various SV types will probably be quite different in terms of characteristics, dynamics etc, all of which will have to be accommodated. A major challenge will be the handling of the initial irregularity of launch and reentry events and the uncertainties these events carry, at the same time as conventional air traffic grows.
Specifying target levels of safety for these new spaceflight operations will also be a notable challenge. These will define the safety envelopes around the SVs, as they do for conventional aircraft, which will determine the minimum safe separation between them, that should include considerations of system failures and malfunctions. It has been shown currently with drone traffic management that regulatory requirements are still catching up to the technology and if these are lacking behind for CSF, that will also delay uptake and deployment.
The enabling technologies to accurately detect, track and communicate with the SVs still need to be defined, as well as their functional and safety requirements, in the same way the so-called Communication, Navigation and Surveillance requirements have been well defined and understood in ATM.
In summary, the main challenges are how we efficiently deploy the technologies to enable these operations routinely and integrate them with existing air traffic, and then think about how to actually manage that specific traffic, as this will follow from the ground work conducted.
Q - Does this vary going through traditional airspace – take off, ascent, descent and landing – vs. when the aircraft reaches its flight level?
SH: Spacecraft have much less manoeuverability than aircraft, and need wide launch corridors to cope with potential failures (much less reliable than aircraft). Space vehicles spend relatively little time in useful airspace (below 20 km).
DP: Yes – it is expected that the launching and re-entry phases of SV operations will need large vertical portions of airspace to be restricted to other traffic and the size of those areas will be defined by the characteristics of the SV (incl. manoeuvrability, position and navigation accuracy, and the safety envelopes we discussed earlier etc). Those areas will also have to consider any risk of potential debris from the SV to conventional air traffic and any malfunction that the SV may have.
Q: Who should be responsible for this airspace management?
SH: Airspace – seems naturally to fall within national responsibilities; orbital space is not controlled nationally (or internationally), and the conventional start of space is at 100 km.
DP: That will be a very interesting conversation amongst the existing (and potentially new) organisations within each country. We are already seeing the positioning of existing ANSPs, which provide Air Traffic Control in national airspace, to diversify and extend their services to include the catering to CSF and SVs. Clearly, they have the experience of deploying the required training and licensing methods to enable commercial flights, and it can be envisaged that just as specific licenses currently cover a variety of ATM operations (e.g. Airport specific, radar specific etc), in the future you would have CSF specific.
On the other hand, space agencies have all the experience of space operations so far, and they might look to diversify and extend their services and offering. It will be interesting to see how things.
Q - Do you see (ATC type) tools specifically for this airspace, able to share information with existing tools or added into existing functionally?
There are certainly synergies with ATM/ATC that should be leveraged. For example, it has already been demonstrated that technologies such as ADS-B (Automatic Dependent Surveillance – Broadcast) that are prevalent in ATM, can effectively be used to track satellites, and thus by extension these could be easily used to support the management of CSF and SV traffic. This is an area Cranfield is currently investigating, as a holistic and seamless ecosystem will be needed, using existing resources and technologies that work to extend the offering in all levels of airspace.
Q – What types of vendors do you see developing these solutions?
We anticipate that this emerging market will open up opportunities both for existing Aerospace and ATM players, but also for disruptive startups in a similar way we have seen for commercial drone operations but as well for new satellite-based services (e.g. imagery, observations etc).
Q – Is there anyone you see who is already addressing this?
The ATM world is already looking at extending its competence into low Earth orbit – but only under discussion so far.
Q – Over what time frame does this become an issue and need to be resolved?
SH: Space Traffic Management is needed to manage the space debris environment and to continue safe access to Earth orbit. Within the next 20 years the risk of debris collision with active satellites is expected to start increasing uncontrollably at some orbit heights unless significant actions are taken to remove debris before then; debris collisions would eventually become an operational threat to spacecraft at these heights.
DP: As mentioned above, an existing challenge is how to integrate the cadence of launches needed for some of the mega-constellations now planned. Clearly some scheduling needs to take place, but the frequency of these can be managed tactically still.
The seamless, safe and routine integration with ATM will be needed when these CSF and SV launches become routine and frequent. However, we already need to start figuring out how to address the challenges, not to be in a situation where the technology and commercial appetite and deployment are so much more advanced than the definition of safety requirements and regulatory frameworks, which then stifles the pace of innovation until it catches up. We have seen this in the drone world and we should already learn those lessons early on.
Q – What types of activities is Cranfield participating in related to these topics?
SH: Several current activities, and especially in the technologies needed to observe space objects and to quantify collision risks. We also have work on space debris mitigation and remediation, and wider interests to explore the synergies between airspace traffic management and space traffic management.
DP: We have started looking for synergies between our space activities and ATM/ATC activities, from the technologies and the concept of operations, and started looking at linking the separate the digital twins we were developing, to put together a holistic ecosystem addressing all levels of airspace from ground operations to CSF and SV traffic management.
