Written Evidence Submitted by Newton Launch Systems
Newton Launch Systems is a space technology company that has been involved in a number of studies relating to satellite launch from the UK, including analysis of launch from an airborne carrier. Based on work undertaken during the Horizontal Spaceport Development Fund study with Spaceport Snowdonia in 2019, we have concerns regarding the safety of the failed January 2023 Virgin Orbit launch. We have been prompted to write this note by recent criticism of the Civil Aviation Authority (CAA) and the suggestion that their safety processes were too onerous. We do not believe that this is the case and, as detailed below, have additional concerns that should be addressed before it is re-attempted.
Currently the global best practice is the USA’s FAA guidance framework, a key part of which is that the Conditional Expected Casualty (CEC) rate from an actual failure prior to or during launch must not exceed 10-3. This gives rise to two specific areas of concern for us.
1. Blast safety zones
At any point after fuelling, there is a risk of the launch vehicle exploding resulting in fragments of the rocket (and burning fuel) being spread over a wide area. In practice, a low CEC from such an event is achieved by defining a blast safety zone around the launch vehicle, within which non-essential personnel are not permitted once the launch vehicle is fuelled. The radius of the zone is dependent on the size of the vehicle, expressed in equivalent TNT, and the availability of shelter, e.g. buildings. As a rough approximation for bi-propellant rockets, the equivalent TNT is 20% of the propellant mass (fuel and oxidiser), so for the Virgin Orbit launcher with a propellant mass in excess of 20 tonnes, the equivalent TNT will be at least 4 tonnes.
FAA guidance  defines the radius of the safety zone in terms of the Hazard Fragmentation Distance (HFD). Table 1 shows the results of an analysis Newton Launch Systems previously undertook as part of a previous study . The 500 kg payload example in the bottom row of the table, is the lowest in size to Virgin Orbit’s Launcher One. Two categories of shelter are considered: “HFD (open)” for people outside and “HFD (inside)” for people within a building. According to Table 1 there should have been no occupied building within 374m of the vehicle from the point of propellant loading to take-off. The corresponding distance for outdoor spectators or non-essential employees is 747m.
Table 1 Hazard Fragmentation Zone
HFD (open) (m)
Video evidence from the January 2023 Virgin Orbit launch shows significant numbers of people, including members of the public, in close proximity to the aircraft and its
fully-fuelled rocket as it taxied to the runway - for example, photographs published by the Guardian newspaper  showing spectators well within this radius crowded around the site’s perimeter fence.
Although the risk of the rocket exploding while on the ground is quite low, if the FAA recommendations had been applied, CEC would clearly have been greater than 10-3 in this case, i.e. had the rocket exploded, people would have been killed.
2. Potential impact zone in the vicinity of the Canary Islands
Applying the CEC methodology to the launch of the rocket after its release from the aircraft, care must be taken to minimise the risk of the vehicle crashing into populated areas in the event of any system failure.
This is assessed by performing a series of trajectory simulations with the rocket thrust cut off at various points in the flight to determine a range of possible impact points. The overall risk to life is then determined by taking account of the population density of the impact zones. This type of analysis was undertaken as part of the same study as the HFD analysis referred to above and the results are presented graphically in the report . Although this study considered the launch vehicle taking off from a different location, the launch point for the rocket vehicle was very similar to the location used by Virgin Orbit (i.e. a range southwest of Ireland). The analysis showed that the flight path of the launcher would pass close to Madeira and particularly the Canary Islands, with a significant risk of impacting the islands in the event of, for instance, the second stage engine shutting down prematurely.
We concluded for safety reasons that it would be preferable to move the launch location approximately 300 km west of Ireland to avoid the Canary Islands altogether, reducing CEC by a factor of 1000. Given that the advantage of Virgin Orbit’s air launch system is that the operator is free to choose the launch point, it is surprising to us that the launch took place from where it did despite the elevated risk. Considering that the second stage of the vehicle was filmed passing close to the Canary Islands after failing to reach orbit,
this appears to have been an avoidable “Near Miss” event, where a small change in trajectory could easily have caused a direct impact.
Work undertaken by Newton Launch Systems over the past decade has highlighted a number of difficulties and safety concerns relating to satellite launch from the UK, due to its location, proximity to other countries and islands, high population density, crowded airspace and busy seas including shipping lanes and oilfields. While these concerns do not preclude launch from the UK, they do highlight the need for a cautious regulatory approach with a focus on safety.
It is widely accepted that novel launch systems have a higher failure rate than well-established launchers, as it takes time and multiple iterations to create reliable systems in any industrial sector. This is highlighted by the fact that 2 of Virgin Orbit’s 6 launches to date have ended in failure. While the CAA’s processes relating to launch vehicles may appear to be an unnecessary burden to some, a catastrophic failure involving damage to property or loss of life would be a far more serious blow to the prospects of future launches from the UK.
The Horizontal Spaceport Development Fund - Final Report by Spaceport Snowdonia to the UK
Space Agency (not published)