Satellite launches like the recent SpaceX expedition, the United Arab Emirates Mars mission and Internet-providing balloons all need to pass through conventional airspace on their way to operations above FL600.

This often involves a temporary flight restriction (TFR) and a notice to airmen (NOTAM). A typical NASA Shuttle launch, for example, required restricted airspace 30-40 nautical miles long and wide, closing off approximately 1,500 square miles to scheduled civil traffic.

With spaceports proliferating worldwide, all air navigation service providers (ANSPs) need to be aware of the challenge. And they must balance such requirements with changes in normal airspace use following the COVID-19 pandemic.

Moreover, the legal framework and standards governing flights intended for suborbital and orbital journeys need further development.

COVID-19 has changed day-to-day aviation but not the overall trajectory of the industry. As new traffic patterns emerge, they will need to accommodate the increase in commercial space activity. 

The continuous growth of air and space traffic means an integrated approach is needed to account for vehicles, manned and unmanned, heading to and returning from space.

But the two frameworks guiding civil air traffic and space flight have some major differences. In essence, the Chicago Convention talks of airspace and aircraft and a 1967 Outer Space Treaty deals with space and space objects. Somehow, these two high-flying regimes must find common ground.

A crucial difference is sovereignty. Article 1 of the Chicago Convention makes it clear that the airspace above a territory belongs to that territory. The Outer Space Treaty is equally assured in stating that no nation can “claim” space. 

Liability is another issue. It lies with the air carrier in the Chicago Convention, with the launching country according to the Outer Space Treaty. Certification, safety standards and – crucially in the modern age – environmental responsibility are other areas in need of harmonisation.

Broadly speaking, there are two approaches to the problem of integrating the two frameworks known as functionalism and spatialism. The former takes the vehicle as a point of reference; is it an aircraft or a space object? The latter looks at where that vehicle is. Neither method has yet won universal approval.

Defining a boundary

The United Arab Emirates has launched its Hope Probe from Japan’s Tanegashima Space Center.

Overseen by a space centre in Dubai, the seven-month, $200m voyage will study the Martian atmosphere and climate, including daily and seasonal changes.

Ultimately, the UAE plans for a Martian settlement.

Mission to Mars

Functionalism notes that vehicles operating in the vacuum of space are not aircraft as explained by the Chicago Convention.

But in the descent phase of a reusable vehicle it might technically become an aircraft. Indeed, the problem is that with so many different types of vehicles and launches, understanding what is an aircraft and what is a spacecraft is fraught with challenges.

The spatialist approach generally settles on a line 100km above the Earth’s surface as a notional boundary between airspace and space. It is an arbitrary marker, though, given a lack of scientific consensus.

Also, defining what is suborbital or orbital is a question of speed and not of altitude. No matter the altitude of a flight, it is deemed suborbital so long as the velocity is below 28,400km/h (orbital velocity). Many of the space tourism flights will operate, for a brief period of time, above the 100km limit yet won’t achieve orbital velocity, suggesting that they would be governed by two separate regimes.

And then there are geopolitical considerations, such as rockets or spy planes, that use certain altitudes and make it hard to achieve an international consensus.

Functionalism and spatialism

A paper by the Space Safety Law and Regulation Committee of the International Association for the Advancement of Space Safety (IAASS) notes that “commercial development of space would be much enhanced by clarity, stability and predictability of law”.

Failing to define the boundary of outer space, it states, may “thwart the proper and orderly governance of outer space and the certainty and strength of international law governing space activities”.

Investment in space transportation might be impaired, as would the insurance industry’s ability to assess and price risk.

The most sensible initial effort might be for ICAO to amend its Annexes to clarify that suborbital vehicles fall within the definition of aircraft. Alternatively, ICAO could promulgate a new Annex 20 on Space Standards.

The IAASS paper suggests a third layer, Near Space, operating within agreed parameters from Earth, such as 50km-160km.

Whatever the final decision, the paper concludes that “delineation of which legal regime applies – in airspace, Near Space, and Outer Space – will clarify rights and obligations, and enhance the margin of safety for aircraft, spacecraft and aerospace vehicles operating in all three zones.”

To speed matters along, ICAO and the UN Committee on the Peaceful Use of Outer Space [COPUOUS] have held several joint meetings and symposia and created a joint Learning Group on the question.

CANSO is playing its part too, continuing to work with all stakeholders to ensure that safety remains paramount for all airspace users, no matter what the altitude. CANSO is promoting coordination between the ICAO Space Learning Group (SLG) and the United Nations Office for Outer Space Affairs (UNOOSA) to ensure a common understanding of future needs, for both ANSPs and the emerging commercial space industry.

The IAASS third layer