Observe its destruction during atmospheric re-entry from inside a satellite

Over nearly seventy years of spaceflight, some 10,000 intact satellites and rockets have re-entered the atmosphere, and many more will do so in the future. However, for such a frequent occurrence, we still don’t have a clear view of what really happens to a satellite during its final moments as it burns up.

The European Space Agency (ESA) is preparing the Draco (Destructive Reentry Assessment Container Object) mission, which will collect unique measurements during an actual reentry and breakup of a satellite from the inside. A capsule specially designed to survive the destruction will transmit the valuable telemetry shortly after.

The Deimos company has signed a first contract worth 3 million euros to begin the development of the satellite. The launch is planned for 2027.

Reentries avoid space debris

To keep Earth’s valuable orbits clean and prevent the creation of more space debris, it is important to quickly remove a satellite from orbit after its mission is complete. ESA is committed to its ambitious “zero waste” approach, which will put an end to the creation of more space debris by 2030. At least as far as ESA is concerned.

Satellites can be built to perform controlled re-entry or, with a little more effort, some can perform assisted re-entry or directed re-entry. However, it is more efficient to meet space debris reduction guidelines if it is “designed to disappear” from the beginning and completely disintegrates during reentry.

“Reentry science is an essential component of disintegration design work. We need to better understand what happens when satellites burn up in the atmosphere and validate our re-entry models,” says Holger Krag, ESA’s Director of Space Safety.

“Therefore, the unique data collected by Draco will help guide the development of new technologies to build more destroyable satellites by 2030.”

Another important element of reentries is their effect on the atmosphere itself, an increasingly important area of ​​research as the number of launches and reentries rapidly increases. Studying how pieces and particles of spacecraft materials wear down and break off in the upper atmosphere can provide insight into what byproducts are created and where. This allows scientists to understand the environmental impact, which in turn will lead to more sustainable designs in the future.

Burn and not burn

“While it is difficult to obtain data from a satellite during its destruction, it is currently impossible to recreate the exact circumstances on the ground. We can use experimentation to test various materials and elements of a spacecraft in wind tunnels on a limited scale,” says Stijn Lemmens, Draco project manager at ESA’s space debris office.

“But it is not yet possible to faithfully imitate the incredible speed, force and movements of uncontrolled reentry. For more complete imitations, virtual modeling is a great tool that can handle either extreme, but it needs calibration and data sets to draw on.”

To obtain this new and unique data set, a destructible satellite must be built with an indestructible capsule on board for in situ observations, which poses its own challenges.

“Draco has to be a spacecraft in low Earth orbit to be a representative reentry and it also has to be equipped with sensors and cameras strong enough so that they can collect data for as long as possible while the satellite around them burns up,” explains Stijn.

“On the other hand, its indestructible capsule must be able to withstand the forces of re-entry, in addition to being able to protect a computer system throughout the violent destruction process while still connected to the sensors, with the wiring coming out of it like an octopus.” .

Once before, in 2013, ESA attempted to observe reentry from inside a spacecraft with a camera mounted inside an automated transfer vehicle (ATV), a cargo shuttle to the International Space Station. The Draco mission aims to collect a much more comprehensive data set.

Unlike previous experiments, Draco’s sensors will measure temperatures, assess stress on various parts of the satellite itself, and record surrounding pressure. Four additional cameras will be pointed at the spacecraft to observe the destruction and gather contextual information.

Artist’s recreation of Draco re-entering Earth’s atmosphere. (Image: ESA / D. Ducros)

Draco’s short life

The final Draco satellite, weighing about 200 kilograms and the size of a washing machine, will not have a propulsion system or connected navigation and communication systems, as it will not be directly controlled. Most reentries are uncontrolled, the satellites remain passive as the atmosphere engulfs them, and Draco’s goal is to mimic a typical reentry as much as possible.

Instead, Draco will take advantage of the steering capabilities of the rocket it launches with in order to line up for rapid re-entry. After a flight of no more than 12 hours, during which it will reach a maximum altitude of 1000 kilometers, Draco will re-enter an uninhabited area of ​​the ocean, its 200 sensors and 4 cameras will record its scorching disappearance and store the result safely in the capsule. .

When the satellite has burned up, you will face your next obstacle. The 40-centimeter capsule could spin and fall at high speed, but it has to be able to open a parachute regardless of its initial orientation and speed.

Once the parachute is deployed, the capsule will descend more gently, allowing it to connect with a geostationary satellite located above to transmit the collected data. The capsule will have about 20 minutes to send telemetry before falling into the ocean and ending the mission.

“Draco is an exciting mission that will provide new and revealing data on many of the unknowns that arise during satellite re-entries,” said Tim Flohrer, director of ESA’s space debris office. (Source: ESA)