Orbital Heat Shield

Type

Technology, Spacecraft Component

Function

Enable safe re-entry and deceleration of spacecraft

Material Types

Ablative (plastic resin), Thermal Soak (insulating materials, ceramic/composite tiles, reinforced carbon-carbon), Inflatable

Primary Purpose

Protect spacecraft from extreme aerodynamic heating during atmospheric re-entry

Key Challenge (Starship)

Developing a durable, fully reusable design

Temperature Withstood (Space Shuttle HRSI tiles)

Up to 1,260 °C

Temperature Withstood (Space Shuttle hottest parts)

Up to 1,650 °C

Temperature Withstood (Galileo probe, Jupiter atmosphere)

Up to 16,000 °C

1980s

1996

2022-11-10

Heat shields protect spacecraft and their payloads upon re-entry into Earth’s atmosphere, playing a primary role in space travel. Space heat shields rely on advanced materials and engineering principles. Their sophisticated design delivers protection from the extremely high temperatures spacecraft encounter from atmospheric friction. The engineering and science behind the shields and how they work are critical to the successful use of heat shields in defense and space travel. [...] ## Space Heat Shields Re-Entry Applications Space heat shields are primarily used to protect re-entry vehicles and spacecraft during their return to Earth. Unmanned and manned spacecraft depend on the heat dissipation from space heat shields to withstand the extreme temperatures of atmospheric friction during re-entry. The heat shields accommodate controlled descent and preserve the mission’s crew and cargo. [...] The military defense and space exploration sectors continuously evolve, with highly-developed heat shields playing a pivotal role in their advancements. Heat shields are critical in ensuring the safety and integrity of space-faring crafts and military defense assets traveling at hypersonic speeds and entering the Earth’s atmosphere from orbit. We will explore advanced heat shields, their applications in the space and military sectors, and the advancements they have delivered to the national

An ablative heat shield consists of a layer of plastic resin, the outer surface of which is heated to a gas, which then carries the heat away by convection. Such shields were used on the Vostok "Vostok (spacecraft)"), Voskhod "Voskhod (spacecraft)"), Mercury, Gemini, and Apollo "Apollo (spacecraft)") spacecraft, and are currently used by the SpaceX Dragon 2, Orion "Orion (spacecraft)"), and Soyuz "Soyuz (spacecraft)") spacecraft. [...] A thermal soak heat shield uses an insulating material to absorb and radiate the heat away from the spacecraft structure. This type was used on the Space Shuttle, with the intent for the shield to be reused with minimal refurbishment in between launches.( The heat shield on the space shuttle consisted of ceramic or composite tiles over most of the vehicle surface, with reinforced carbon-carbon material on the highest heat load points (the nose and wing leading edges).( This protected the [...] With possible inflatable heat shields, as developed by the US (Low Earth Orbit Flight Test Inflatable Decelerator - LOFTID)( and China,( single-use rockets like the Space Launch System are considered to be retrofitted with such heat shields to salvage the expensive engines, possibly reducing the costs of launches significantly.( On November 10, 2022, LOFTID was launched using an Atlas V rocket and, then, detached in order to reenter the atmosphere.( The outer layer of the heat shield consisted

“An IHS acts as a thermal protection system and as a decelerator and can enable safe re-entry and deceleration of a spacecraft after de-orbiting,” says Simone Centuori, CEO of Deimos, which heads up the ICARUS project. An IHS’ flexible thermal protection system (TPS) and inflatable structure work together in tight collaboration. The shield is stowed in a folded configuration until re-entering a planet’s atmosphere, when it is unfolded and inflated, decelerating and shielding the spacecraft. [...] NASA’s pioneering work in IHS technology includes the successful flights of the HIAD (Hypersonic Inflatable Atmospheric Decelerator) on suborbital rockets. Most recently, NASA brought back more than one metric ton from Low Earth Orbit with the LOFTID (The Low-Earth Orbit Flight Test of an Inflatable Decelerator) inflatable heat shield. Sebastian Klaus, CEO of Atmos Space Group says, “These heat shields are also contributing to the research of rocket reusability. United Launch Alliance (ULA) is [...] By the 1980s heat sinks in the form of ceramic heat shield tiles were developed for use on the Space Shuttle and SpaceX’s Starship. The shields were made of ceramic tiles which replaced the heavier metal tiles used previously. The ceramics used included heat-absorbent silica, for example on NASA’s Space Shuttle, and heat-resistant carbon-fibre reinforced carbon. However, these material’s weight, ever the enemy in aerospace, remained an intrinsic problem with their use.

The black HRSI tiles provided protection against temperatures up to 1,260 °C (2,300 °F). There were 20,548 HRSI tiles which covered the landing gear doors, external tank umbilical connection doors, and the rest of the orbiter's under surfaces. They were also used in areas on the upper forward fuselage, parts of the orbital maneuvering system pods, vertical stabilizer leading edge, elevon trailing edges, and upper body flap surface. They varied in thickness from 1 to 5 inches (2.5 to 12.7 cm), [...] A stronger, tougher tile which came into use in 1996. TUFI tiles came in high temperature black versions for use in the orbiter's underside, and lower temperature white versions for use on the upper body. While more impact resistant than other tiles, white versions conducted more heat which limited their use to the orbiter's upper body flap and main engine area. Black versions had sufficient heat insulation for the orbiter underside but had greater weight. These factors restricted their use to