Weight of the space shuttle, empty vs.
Early reentry-vehicle concepts visualized in shadowgraphs of high speed wind tunnel tests The concept of the ablative heat shield was described as early as by Robert Goddard: For this reason, Space shuttle reentry the outer surface of the apparatus were to consist of layers Space shuttle reentry a very infusible hard substance with layers of a poor heat conductor between, the surface would not be eroded to any considerable extent, especially as the velocity of the apparatus would not be nearly so great as that of the average meteor.
For early short-range missiles, like the V-2stabilization and aerodynamic stress were important issues many V-2s broke apart during reentrybut heating was not a serious problem.
Medium-range missiles like the Soviet R-5with a 1,kilometer nautical-mile range, required ceramic composite heat shielding on separable reentry vehicles it was no longer possible for the entire rocket structure to survive re-entry.
In the United States, this technology was pioneered by H. Julian Allen and A. If the reentry vehicle is made blunt, air cannot "get out of the way" quickly enough, and acts as an air cushion to push the shock wave and heated shock layer forward away from the vehicle.
Since most of the hot gases are no longer in direct contact with the vehicle, the heat energy would stay in the shocked gas and simply move around the vehicle to later dissipate into the atmosphere. The Allen and Eggers discovery, though initially treated as a military secret, was eventually published in It is recommended that the reader review the jargon glossary before continuing with this article on atmospheric reentry.
When atmospheric entry is part of a spacecraft landing or recovery, particularly on a planetary body other than Earth, entry is part of a phase referred to as entry, descent, and landing, or EDL. Entry vehicle shapes[ edit ] There are several basic shapes used in designing entry vehicles: Sphere or spherical section[ edit ] Apollo Command Module flying with the blunt end of the heat shield at a non-zero angle of attack in order to establish a lifting entry and control the landing site artistic rendition The simplest axisymmetric shape is the sphere or spherical section.
The aerodynamics of a sphere or spherical section are easy to model analytically using Newtonian impact theory. Likewise, the spherical section's heat flux can be accurately modeled with the Fay-Riddell equation.
Pure spheres have no lift. However, by flying at an angle of attacka spherical section has modest aerodynamic lift thus providing some cross-range capability and widening its entry corridor.
In the late s and early s, high-speed computers were not yet available and computational fluid dynamics was still embryonic. Because the spherical section was amenable to closed-form analysis, that geometry became the default for conservative design. Consequently, manned capsules of that era were based upon the spherical section.
Pure spherical entry vehicles were used in the early Soviet Vostok and Voskhod capsules and in Soviet Mars and Venera descent vehicles.
The Apollo Command Module used a spherical section forebody heat shield with a converging conical afterbody. Even these small amounts of lift allow trajectories that have very significant effects on peak g-force reducing g-force from 8—9g for a purely ballistic slowed only by drag trajectory to 4—5g as well as greatly reducing the peak reentry heat.
The sphere-cone's dynamic stability is typically better than that of a spherical section. The vehicle enters sphere-first. With a sufficiently small half-angle and properly placed center of mass, a sphere-cone can provide aerodynamic stability from Keplerian entry to surface impact.
The half-angle is the angle between the cone's axis of rotational symmetry and its outer surface, and thus half the angle made by the cone's surface edges. The original American sphere-cone aeroshell was the Mk-2 RV reentry vehiclewhich was developed in by the General Electric Corp.
The Mk-2's design was derived from blunt-body theory and used a radiatively cooled thermal protection system TPS based upon a metallic heat shield the different TPS types are later described in this article.
The Mk-2 had significant defects as a weapon delivery system, i. These defects made the Mk-2 overly susceptible to anti-ballistic missile ABM systems. This new TPS was so effective as a reentry heat shield that significantly reduced bluntness was possible.
Subsequent advances in nuclear weapon and ablative TPS design allowed RVs to become significantly smaller with a further reduced bluntness ratio compared to the Mk The sphere-cone was later used for space exploration missions to other celestial bodies or for return from open space; e.
Space exploration sphere-cone entry vehicles have landed on the surface or entered the atmospheres of MarsVenusJupiter and Titan. Biconic[ edit ] The biconic is a sphere-cone with an additional frustum attached.
No accurate diagram or picture of AMaRV has ever appeared in the open literature. However, a schematic sketch of an AMaRV-like vehicle along with trajectory plots showing hairpin turns has been published. Opportunity rover's heat shield lying inverted on the surface of Mars. AMaRV's attitude was controlled through a split body flap also called a split-windward flap along with two yaw flaps mounted on the vehicle's sides.
Hydraulic actuation was used for controlling the flaps. AMaRV was guided by a fully autonomous navigation system designed for evading anti-ballistic missile ABM interception.Landing Follow along with the landing!
Whether the space shuttle lands at the prime landing site at Kennedy Space Center in Florida or its backup landing site at Edwards Air Force Base in California, the Virtual Launch Control Center is the only place online to get breaking information directly from NASA.
Well, less speed would be great ;-). In order to be able to orbit the Earth, the Space Shuttle must fly at ~mph (approx. m/s) – this is the orbital speed in LEO. Before reentering the atmosphere, it must slow down thus it makes a de-o. space systems operate while transiting the atmosphere as they return to Earth.
The technologies for the reentry and recovery from space might change over time, but the challenge remains one of the most important and vexing in the. The Shuttle's Return to Earth - A safe space shuttle return and landing depends on dozens of factors.
Learn about space shuttle re-entry and what caused the Columbia disaster in Remember, reentry is all about losing speed, it's not inherent to space travel. Slamming into the atmosphere is just still the cheapest way of losing orbital speed. Slamming into the atmosphere is just still the cheapest way of losing orbital speed.
Remember, reentry is all about losing speed, it's not inherent to space travel. Slamming into the atmosphere is just still the cheapest way of losing orbital speed. Slamming into the atmosphere is just still the cheapest way of losing orbital speed.