For the first time in almost a decade, NASA and SpaceX are to launch US astronauts to the International Space Station (ISS) from American soil.
Following a delayed green light, NASA will again be firing its own crew into space on Wednesday, 27 May, at approximately 9.30pm UK time.
Here’s what you need to know.
Image: SpaceX has previously delivered cargo to the ISS
What has NASA been doing for the last decade?
NASA’s last manned spaceflight to take off from the US was on 8 July 2011, at which point the Space Shuttle programme was retired.
From its first flight in 1981, the Space Shuttle programme launched 135 times – 133 of which were successful.
The tragic failures of both the Challenger and Columbia orbiters, in 1986 and 2003 respectively, led to the deaths of 14 astronauts – all seven crew members on each mission.
At the time of the retirement of the Space Shuttle, NASA stated it was devoting its resources to sending astronauts back to the moon – and one day to Mars.
Since then NASA has relied on Russian Soyuz spacecraft, operated by Russia’s space agency Roscosmos, to ferry its astronauts to the ISS.
Image: Russia’s Soyuz spacecraft have been used by NASA since 2011
Why is that changing now?
NASA launched its Commercial Crew Program in 2010, to find private sector partners who could launch astronauts safely to the ISS, but funding issues delayed the initial launches.
Russian space launches themselves aren’t cheap – for astronauts travelling to the ISS using Soyuz rockets from the Baikonur Cosmodrome in Kazakhstan, it costs up to $86m (£70m) per seat.
As part of NASA’s programme, two US-based companies – Elon Musk’s SpaceX and Boeing – are going to return this human spaceflight capability to American soil with cheaper seat costs.
It will cost $55m (£45m) for SpaceX and $70m (£57m) for Boeing, although the Boeing figure has been contested and could be as high as $90m (£74m) – making it more expensive than a Soyuz launch.
Image: The Space Shuttle was retired after 30 years in service
Has SpaceX done this before?
Wednesday’s launch marks the first time that SpaceX is taking part in a manned spaceflight, although it has 85 successful launches of its Falcon 9 family of rockets since 2010.
The mission seemed in doubt after a leaked video appeared online last year showing its Crew Dragon spacecraft exploding in flames.
A subsequent joint investigation between SpaceX and NASA revealed that a titanium fire was the probable cause of the explosion.
It was a terrifying moment for the engineers involved in designing the capsule, which is meant to safely carry human passengers in space, but the Crew Dragon was successfully tested afterwards.
Image: SpaceX’s most recent test fire of its Crew Dragon spacecraft was a success
Who are the crew?
The crew for the flight are Doug Hurley and Bob Behnken, who are both experienced astronauts with several spaceflights under their best.
Mr Hurley will be the spacecraft commander and ranking officer, while Mr Behken will be the joint operations commander.
Mr Hurley was also selected as an astronaut in 2000 after a career as a fighter pilot and test pilot in the Marine Corps, and has completed two spaceflights – including the final space shuttle mission in July 2011.
Mr Behnken was selected by NASA in 2000 after a career as a flight test engineer with the US Air Force – he has two space shuttle flights under his belt and six spacewalks.
Image: Bob Behnken (L) and Doug Hurley are both experienced astronauts
Does the launch represent success for Donald Trump?
Donald Trump has been keen to stress his commitment to space projects since taking office, including his desire for NASA to return to the Moon and the launch of the US military’s Space Force.
Although NASA’s Commercial Crew Program began before his administration, the president has told reporters at the White House he was thinking about flying to Florida to watch the launch.
He jokingly told the journalists: “I’d like to put you all on the rocket and get rid of you for a while.”
NASA’s administrator Jim Bridenstine has said: “Under President Trump’s leadership, we are once again launching American astronauts on American rockets from American soil.”
However, he was rebuked by former astronaut Garrett Reisman, who tweeted: “I am thankful for the continued support from you and the Administration but if there is a President to thank for this milestone, it’s Barack Obama.”
Image: President Donald Trump has authorised increased funding for NASA
How long will the launch take?
The astronauts will be accelerated to approximately 17,000mph (27,000kmph) – 22 times the speed of sound – and put on an intercept course with the ISS.
It will take less than ten minutes for the Crew Dragon spacecraft to get into orbit, while the Falcon 9 booster attempts to land on a floating barge in the Atlantic Ocean.
After about 24 hours in orbit, the Crew Dragon will rendezvous and dock with the space station.
Although the spacecraft is designed to do this autonomously, the astronauts aboard both the Dragon and the ISS will be ready to take manual control if necessary.
Image: SpaceX has previously delivered cargo to the ISS
What are the astronauts going to do on the ISS?
Mr Hurley and Mr Behnken are going to work alongside the crew of Expedition 63 aboard the ISS, although their main job is the demonstration flight of the Crew Dragon.
The pair will spend between 30 and 119 days on the ISS, assisting with research on the station and participating in a number of spacewalks.
Image: The ISS is 408km away from the surface of the Earth
Is there a risk of the launch being delayed?
Weather conditions are essential for a safe launch, and the forecast for Wednesday could be better.
Forecasts on Sunday suggested there is a 60% chance of bad weather, although this could change.
If the launch doesn’t take place within the launch window on Wednesday, the next attempt will be on 30 May.
Image: There is a 60% chance of bad weather on Wednesday
According to the US Air Force 45th Weather Squadron, which is supporting the launch, there is a 60% probability of “violating weather constraints”.
These violations include the Falcon 9 having to fly through rain, and through a layer of thick cumulus clouds.
The forecast was due to be updated on Monday.
Source : Sky News