How Do Rockets Get Back To Earth?

The fantastic show of a rocket firing its thrusters to send its cargo into orbit never ceases to amaze. But how can they get back and land safely if people or components of a spacecraft need to return to Earth?

A rocket’s crew or cargo module typically orbits to return to Earth by firing its thrusters. When the craft is in the atmosphere, parachutes open to help it land. Thrusters are used in the early stages of contemporary rockets, like the Falcon 9, to slow the rocket down and extend landing legs for a touchdown.

This article will explore several ways through which rockets get back to Earth. 

Three Ways Through Which Rockets Get Back To Earth 

The three most frequent methods for returning rockets to Earth are listed below:

1. Landing of the Space Shuttle
2. SpaceX Falcon 9 first stage
3. Standard Spacecraft Landing Using Parachutes

Most of these recovery techniques have been tried and true, but as discussed in the following sections, two landing techniques are still experimental.

The ideas and approaches used in the landing and recovery operations are relatively similar and shared. However, there are significant differences in the technologies and policy. We will comprehend each system’s procedure better by examining each in further detail.

1. Space Shuttle Landing

The Space Shuttle (Columbia) made its first flight on April 12, 1981, and its final flight was on July 8, 2011. Launching an Orbiter like a rocket and bringing it back to Earth by landing like a regular airplane transformed how humans travel to and from space.

To save costs and enable more frequent trips, NASAs goal with the shuttle program was to operate a reusable spaceship with rapid turnaround times between launches. Sadly, the initiative was discontinued in 2011 because it was too expensive.

Many of the lessons learned and tools produced during this time are now being used in present and future spacecraft designs. The technology and methodology are still novel today.

The re-entry and landing procedure of a Space Shuttle looked as follows:

• The space shuttle is turned around with its RCS (Orbital Control System) so that its tail faces forward once the cargo doors have been seated and everything is fastened inside the vessel.
• The OMS (Orbital Maneuvering System) thrusters are fired with the craft’s tail pointed forward to slow it down and enable it to begin falling out of orbit.
• The orbiter pitches around once more as soon as it enters the upper atmosphere, with its belly–which houses the heat shields– looking down and its nose pointing ahead.
• The heat shields must be able to absorb and endure temperatures of up to 1650 Celsius (3000 Farrenheit) as the space shuttle reenters the atmosphere at velocities of about 28000 Km/h (17 300 mph).
• About 40 Kilometers (25 miles) before the landing location, the orbiter, which is now virtually a giant heavy glider, slows to subsonic speeds and begins to align itself with the runway.
• The space shuttle executes a landing almost like a regular aircraft after entering a steep dive, raising the nose in anticipation of landing, and lowering the landing gear 15 seconds before touchdown.

Even though the space shuttle fleet is no longer in use, NASA’s Artemis program, which will employ its Space Launch System (SLS) to send people back to the moon, still uses many of its parts and technologies.

1. SpaceX Falcon Landing: Stage 1

A privately held corporation named SpaceX made history on December 21, 2015, when its first stage of a rocket landing became successful.

It fired its engines, extended its landing legs, and soft-landed the rocket in the truest sense. The already well-known SpaceX launched its two-stage Falcon 9 rocket, of which the second stage sent its payload into orbit.

Since a rocket’s first stage, which is the most expensive component of a launch vehicle, may be repaired and reused numerous times, this recovery technique lowers the cost of a rocket launch. The New Shephard rocket from Blue Origin employs a similar strategy.

The re-entry and landing procedure of a Falcon 9 first stage looks as follows:

• Following the launch, the rocket travels along its intended path for the first 162 seconds before its first stage separates from its second stage due to a process known as MECO.
• After the first and second stages separate, the first stage continues to its apogee of about 120 kilometers (74.5 miles). Returning to the planet’s surface. The second stage then continues into orbit.
• The rocket’s tiny cold thrusters turn it around just before reaching its apogee, allowing its main thrusters to point ahead.
•  The primary thrusters now ignite to direct the vehicle’s trajectory in the direction of the landing area.
•  The grid fins of the first stage are deployed to guide and steer the rocket as it begins to reenter the atmosphere.

Watch this amazing video to SpaceX landing its Falcon Heavy Boosters successfully for the first time:

SpaceX Lands All 3 Falcon Heavy Boosters for the First Time

1. How Standard Spacecraft Land With Parachutes 

Most crewed and uncrewed spacecraft return to Earth by deploying giant parachutes that slow them down enough to make a secure landing in the Gobi Desert, diving on land or in the water.

The Crew Dragon ( and Cargo Dragon) from SpaceX executes splashdown in the ocean, making it the most contemporary deployment of this landing technique. China’s Shenzhou spacecraft often lands in the Gobi Desert, while Russia’s Soyuz capsule typically lands in the vast open plains of Kazakhstan.

However, the command module’s well-documented splashdowns during the Apollo missions in the 1960s and 1970s, by employing the concepts still in use today, are the most well-known example of this technique for bringing spacecraft back to Earth.

A typical Apollo Command modules re-entry and landing procedure looked as follows: 

• The Apollo command module must first separate from the service module to reenter the Earth’s atmosphere. (The original Saturn V rocket’s command module is the only component returning to Earth.)
• The command module must approach the atmosphere at a 5.3 to 7.7 degrees angle, whereas a shallower angle will cause it to skim off the atmosphere and return into space.
• The command module must also change its orientation so the heat-shielded portion of the base of the craft faces forward. It will be able to slow down because of the base’s wedge-shaped design.
• The ablative heat shield will withstand temperatures of up to 2760 Celsius after reentering the atmosphere due to the craft’s speed pressing against the dense atmospheric air.
• Two ribbon drogue parachutes are deployed while the capsule is still in the upper atmosphere to slow it down and stabilize it.
• Once the spacecraft has slowed down enough to make a safe splashdown in the ocean, the capsule releases three pilot parachutes to pull out the three ringsail main parachutes.
• After splashdown, the vessel will be secured by a helicopter carrying navy divers before being transported to a nearby naval ship.

The fundamental processes and strategy for re-entry and landing continue to be nearly the same as those used by the Apollo spacecraft more than 50 years ago, even though contemporary capsules like SpaceX’s Crew Dragon use significantly better materials and technology.

Conclusion 

There has been significant advancement over the past 50 years, even though it is evident that no rocket that has reached orbit and beyond has yet been able to return to Earth and land entirely.

With SpaceX successfully landing its whole first-stage booster and capturing its payload fairing, the future of rockets returning and landing safely on the planet’s surface appears bright. In the 1960s, the 110-meter-tall Saturn Rocket could only replace its little command module.