SpaceX is gearing up for a great milestone for human flight.
Elon Musk's company aims to fly the first demonstration mission of its Crew Dragon capsule to the International Space Station (ISS) on March 2.
This flight, known as Demo-1, will be unprotected. But if all goes well, Crew Dragon will probably carry astronauts to and from the circulating lab for the first time this summer. [Take a Walk Through SpaceX’s Crew Dragon]
Here's what you need to know about Crew Dragon, Demo-1 and the short-term future of human spaceflight.
What is Crew Dragon?
SpaceX has developed Crew Dragon under a multibillion-dollar commercial crew contract with NASA. The agency signed a similar agreement with Boeing, working on a capsule called CST-100 Starliner.
The goal is to return orbital human spaceflight to American soil. American astronauts have relied on Russian Soyuz rockets and spacecraft to get to and from the ISS since July 2011, when NASA retired its spacecraft.
A lot of money has flown from NASA to its Russian counterpart, Roscosmos as a result; seats aboard the three-person Soyuz spacecraft are currently selling for about $ 80 million.
Crew Dragon will launch on SpaceX's workhorse Falcon 9 rocket, a two-stage vehicle with a reusable first stage. Starliner, which is scheduled to make its weed maiden flight to ISS sometime in April, will be lifted by United Launch Alliance Atlas V rockets that cannot be reused.
How is it different from Cargo Dragon
Crew Dragon is a modified, upgraded version of SpaceX's Robotic Dragon Cargo Capsule, which since 2012 has relocated effortless resupply missions to the ISS under another NASA contract.
The Crew Dragon has many astronaut-related features that lack its robotic cousin – for example, seats (seven of them), windows, fancy touchscreen displays, a life support system and a flight system. The Escape system, designed to get the Crew Dragon out of trouble in the event of an emergency, consists of eight SpaceX SuperDraco engines built into the capsule body.
There are also other important differences between the two vehicles. For example, Dragon has traditional deployable solar frames, but Crew Dragon's solar panels cover the spacecraft's luggage compartment and require no action to activate.
Both Dragon variants are designed to be recyclable, and SpaceX has already reflowed several of the cargo vessels on ISS missions. But each Crew Dragon won't fly multiple ISS missions to NASA, at least not originally, SpaceX representatives have said
What will Demo-1 do?
((VideoProviderTag | jwplaDemo-1 is launched from the historic launch complex 39A at NASA's Kennedy Space Center in Florida. SpaceX is targeted on liftoff on March 2, but that date is far from set in stone.
The mission is designed to test almost all Crew Dragon's critical equipment, from its automatic approach and docking gear to its life-support and re-entry systems. SpaceX staff will carefully monitor the performance of these systems during the approximately 2-week mission, ending with a parachute-supported splashdown in the Pacific.
But a successful return to Earth will not announce the will of Crew Dragon to carry crew. SpaceX will also perform an effortless "abortion test" with the capsule in June to ensure the proper functioning of the escape system.
If everything goes well with both of these flights, Demo-2 will be cleared for liftoff. This mission, which could start as early as July, will take NASA astronauts Bob Behnken and Douglas Hurley to the ISS for about a week's stay.
Operation crew missions to the NASA Circuit Laboratory would follow the successful implementation of Demo-2.
Prelude to Starship?
If SpaceX's vision holds, the Crew Dragon will not fly too long – nor will it carry the Dragon or Falcon 9 and Falcon Heavy rockets.
SpaceX builds a new do-it-all spaceflight system consisting of a 100-passenger spaceship called Starship and a giant rocket called Super Heavy. The reusable duo will carry people to and from Mars, the moon and other distant destinations, Musk has said, and doing whatever SpaceX needs, from launching satellites to tidying up space.
Starship and Super Heavy will also do some work closer to Earth's surface, ferrying people on super-fast point-to-point tours around the globe.
Mike Wall's book on the search for alien life, "Out There" (Grand Central Publishing, 2018, illustrated by Karl Tate) is out now. Follow him on Twitter @michaeldwall. follow us @Spacedotcom or Facebook. Originally published on Space.com.