006 - Design of Re-entry Alert Service
Purpose
This design document proposes a design for a re-entry alert service for government users.
Context and scope
One of the key responsibilities for Monitor Space Hazards is to present and distribute alerts on re-entry events to users across the UK government and internationally.
Previously, UKSA produced re-entry alerts manually and subsequently distributed them to UK government users via email. These alerts were time consuming to produce and distribute, prone to human error, and resulted in unnecessary delays to cross-government communication.
Goals and non-goals
The goal of this Design Doc is to articulate a design for the new re-entry service for government users.
Goals
- Develop a re-entry service for government users which provides all the information users need in a user-friendly way
- Ensure the service enables automatic distribution of notifications to users to remove human error, reduce time delays and save time for UKSA staff
The actual design
Developing re-entry alerts
The re-entry service takes the form of a series of alerts on re-entry events which are escalated according to criteria defined by the UK Space Agency. These alerts will sit alongside a feed of TIPs data from Space track. The re-entry service will therefore mirror the structure of the conjunction service, containing both standard reports with data from Space Track and alerts developed by UKSA’s Orbital Analysts.
The alerts contain 9 separate sections:
Executive summary: A brief introduction to re-entry events, followed by a table of key event details, such as risk level, probability of re-entry over the UK, predicted re-entry times, object details, and regions potentially affected.
Additional object and orbit details: A table of event details which are not included in the Executive Summary, such as object ID codes, object dimensions, launching year and descriptions of the objects orbit.
Potential impact by UK nation: A table containing the probability of re-entry and time of overflights for each of the four UK nations.
Potential impact by UK region: Tables containing the probability of re-entry and time of overflights for 32 UK regions.
Potential impact by British Overseas Territory: A table containing the probability of re-entry and time of overflights for 14 British Overseas Territories.
Guidance on response: A summary of the UK government response to re-entry events, including immediate response, recovery and clean up.
Liability for damages: Information regarding who is liable for any damages caused based on the licensing country and owner of the re-entering object.
Press attention: A summary of press attention regarding the re-entering object.
Re-entry event history: A summary of key event details across several report updates, including time of update, risk level, probability of re-entry over the UK, and UK overflight time(s).
Risk thresholds: A table outlining the thresholds used to determine risk levels for each event.
Further information: A list of organisations which have received a notification for the event, and a link to more information about how the analysis is conducted.
To maintain a simple user interface, all sections other than the Executive Summary are contained within accordions. The page also provides an option for users to download the event report as a PDF.
These alert pages were tested with a wide range of potential users.
Building the re-entry homepage
The re-entry homepage was developed to maintain consistency with the conjunction homepage. It includes a summary table on the number of upcoming re-entry events and alerts at the top of the page. Below this, the page shows a table of all upcoming and past re-entry events and alerts identified by the service, based either on Space-Track TIPs or analysis provided by UKSA’s Orbital Analysts. This table is filterable by date and re-entry event or alert.
Distributing re-entry alerts
Notifications for re-entry alerts were designed to closely replicate UKSA’s existing Standard Operating Procedures for escalating re-entry reports. There are therefore three distribution lists:
Distribution list 1: receives notifications for all re-entry alerts
Distribution list 2: receives notifications for priority re-entry alerts only
Distribution list 3: receives notifications for re-entry of UK-licensed satellites only
Users will be able to select which distribution list they are on; however, the default settings for each user will reflect the distribution lists they were on prior to digitisation of the service. A set of pre-defined criteria determine whether notifications are sent to the extended distribution list. Those at UKSA of the ‘Approver’ type will also be able to manually send notifications to users - either selecting the extended distribution list or inputting selected email addresses to send notifications to. If meeting the criteria to receive notifications about an event, users will receive notifications when the event is first identified, an update is made to the event, and when the event is closed down.
Alternatives considered
The re-entry alert service was developed through a series of rounds of prototype development and user testing. Through this process a wide range of iterations of the design were considered until the final design was reached.