Science

Space Debris: Feel the Burn – Designing Satellites To Fall Apart

This may be counterintuitive, but designing a better decomposed satellite is one of the key strategies to combat space debris. The method was developed by ESA’s Clean Space Program and is called “disappearance design”, and it involves ensuring that abandoned satellites are completely shattered and burned when they re-enter the atmosphere.

The hardware that re-enters space should be completely burned out during the process of submerging itself in the atmosphere to ensure safety. In practice, some fragments can reach the earth, and some of them are large enough to cause serious damage.

For example, in 1997, Texans Steve and Verona Gutowski were awakened by an impact that looked like a “dead rhino” just 50 meters from their country home. It turned out to be a rocket-class 250 kg fuel tank.

Space Debris Texas
The main propellant tank of the second stage of a Delta 2 rocket landed near Georgetown, Texas, USA, on January 22, 1997. This tank of about 250 kg is primarily a stainless steel structure and survived reentry relatively intact. Credit: NASA

Modern space debris regulations require such incidents not to occur. Uncontrolled re-entry must be less than one in ten thousand chance of injury to ground personnel.

As part of a larger effort called cleanat, ESA is developing technology and techniques to ensure that future low-orbit satellites are designed according to the “D4D” concept-the disappearance design.

Some heavier satellite elements are more likely to survive the reentry process. These include magneto-caloric motors that use magnets to change the direction of the spacecraft relative to the earth’s magnetic field, optical instruments, thrusters and pressure tanks, drive mechanisms that operate solar panels, and reaction wheels-satellites that use rotating gyroscopes to change the pointing direction.

Satellite Reentry

An element of the D4D research is to melt these huge elements in a plasma wind tunnel capable of reproducing the fire conditions involved. The other is to plan methods to ensure that the re-entering debris dissolves quickly.

During the reentry process, peak heat flux and mechanical loads usually cause the satellite to rupture at an altitude of approximately 75 kilometers. Only after this height, most of the internal equipment exposed to the heat flow will begin to “fading”.

Breaking Apart on Reentry

But designing a higher breakdown height means that the internal equipment will be exposed to the heat flow for a longer time, which greatly improves its overall ability not to be missed. Possible ways to ensure this include more fusible joints for connecting satellite panels or the use of “shape memory alloys” that change shape with temperature.

Clean Space also uses DRAMA (Debris Risk Assessment and Mitigation Analysis) software to calculate the compliance of a given satellite design with space debris mitigation standards, and to ensure that the latest research results are taken into account, and risk reduction is always the goal. Injured below. The key value of one ten thousandth.

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