On May 30, 2020, SpaceX became the first company to send humans to orbit on a commercial spaceship, launching two NASA astronauts to the International Space Station in a Dragon capsule. This was the first manned flight from the US since 2011 when NASA retired its program. After an approximately 19-hour trip, the two astronauts, Doug Hurley and Bob Behnken will move into the station along with its current occupants, NASA’s Chris Cassidy and Russia’s Anatoly Ivanishin. For the return trip, the pair will be able to strap themselves back into the Dragon and descend to an Atlantic splashdown.

 

The rocket used for the launch is the Falcon 9, a reusable, two-stage rocket for reliable and safe transport into orbit and beyond. While most rockets are expendable launch systems, the first stage of Falcon 9 is capable of re-entering the atmosphere and landing vertically with the use of grid fins that deploy after separating from the second stage. The first stage’s 9 engines, designed for recovery and reuse, use rocket grade kerosene (RP-1) and liquid oxygen as propellants in a gas-generator power cycle. The second stage’s engine is a vacuum-adapted design of the same type.

 

To make the design as fault-tolerant as possible, SpaceX uses multiple redundant flight computers. Three voting computers, each with two physical processors that continuously check each other, control every engine. Each stage also has stage-level flight computers, separate from those that control the engines. The software runs on Linux and is written in C++, and every engine microcontroller CPU runs on a PowerPC architecture.

 

The Dragon capsule is built for spaceflights into and from low-Earth orbit and is a redesign of the unmanned spacecraft that was being used to resupply the ISS. After six years of development and testing, the current capsule is capable of carrying up to 7 passengers, as well as transporting cargo in a second trunk compartment. It is equipped with 16 thrusters in order to orient the spacecraft during a mission, including orbit adjustment and altitude control. A parachute system is included to stabilize and decelerate for its return descent into an ocean landing.

 

This first flight serves as an initial demonstration of the Dragon’s capabilities with a crew on board and, if entirely successful, yet another Dragon will carry four astronauts to the ISS upon Hurley and Behnken’s return. Since 2011, NASA has relied on Russia’s Soyuz rocket to fly crew to the ISS and one seat runs about $80 million. Having the Crew Dragon would alleviate this cost, as well as open up the possibility of private flights operated by SpaceX, which owns the space-taxi hardware.

 

Watch the launch below.

 

 

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