The English used in this article or section may not be easy for everybody to understand. (July 2020)
|Founded||6 May 2002|
|Owner||Elon Musk Trust|
(54% equity; 78% voting control)
Number of employees
|Footnotes / references|
Space Exploration Technologies Corporation, mostly known as SpaceX, is a space transportation company based in Hawthorne, California. It was founded in 2002 by Elon Musk, who also founded PayPal and Tesla. The company develops rockets that can lift cargo into space, fly it to the International Space Station (ISS), and safely return cargo back to Earth. In December 2010, it became the first private corporation to successfully launch, orbit and recover a spacecraft. In May 2012 it was the first private company to send a cargo to the ISS, and it returned.
It was the first private company to send astronauts to orbit and to the International Space Station (SpaceX Demo-2 in 2020). SpaceX has flown the Falcon 9 series of rockets over one hundred times; Each rocket is designed to be used more than one time.
History[change | change source]
In 2001, Elon Musk proposed a project to land a small greenhouse to grow plants on Mars. He said, "This would be the furthest that life’s ever traveled" in an attempt to regain public interest in space exploration and increase the budget of NASA. Musk tried to buy cheap rockets from Russia but returned empty-handed after failing to find rockets for an affordable price. Later, Musk realized that he could start a company that could build the rockets he needed. According to early Tesla and SpaceX investor Steve Jurvetson, Musk calculated that the raw materials for building a rocket were actually 3% of the price of a rocket at the time. By applying vertical integration, producing around 85% of launch hardware in-house, and the modular approach from software engineering, SpaceX could cut launch price by a factor of ten and still enjoy a 70% gross margin.
In early 2002, Musk was seeking workers for his new space company, soon to be named SpaceX. Musk found a rocket engineer Tom Mueller (later SpaceX's CTO of Propulsion). He agreed to work for Musk. That was how SpaceX was born. The first headquarters of SpaceX was in a warehouse in El Segundo, California. The company has grown rapidly since it was founded in 2002, growing from 160 workers in November 2005 to 1,100 in 2010, 3,800 workers and contractors by October 2013, nearly 5,000 by late 2015, and about 6,000 in April 2017. As of November 2017[update], the company had grown to nearly 7,000. In 2016, Musk gave a speech at the International Astronautical Congress, where he explained that the US government uses rocket technology as an "advanced weapon technology", making it difficult to hire non-Americans.
Launch vehicles, spacecraft, and rocket engines[change | change source]
Early Vehicles[change | change source]
The Falcon 1 was SpaceX's first launch vehicle. It launched a total of 5 times, however only the 4th and final flights were successful. Falcon 1, as the name implies, ran on 1 Kestrel engine and could take a maximum of 670 kilograms to orbit.
Another early vehicle was the canceled Falcon 5, which has 5 Merlin engines on its first stage, and 2 Kestrel on its second stage. It was canceled in 2007 when it was removed from the company's user guide.
Current Rockets[change | change source]
The Falcon 9 is an working, reusable two-part rocket that is launched using its nine Merlin engines in its first part and a special Merlin engine that was made for places where there is no air. It is powered by liquid oxygen and fuel made for rockets called RP-1. It can hold up to 22,800 kilograms (50,300 pounds), and can also support SpaceX's Dragon vehicle. It is the first rocket able to get into orbit that can get its first part back to earth.
Falcon Heavy is another working, reuseable rocket similar to Falcon 9. However, the Falcon Heavy has a three-core system for its first part instead of the single-core design of the Falcon 9. With the three cores, the rocket's 1st part has 27 Merlin engines. The second part still only has 1 Merlin(Vacuum Version) engine. Currently, Falcon Heavy is the world's most powerful operating rocket and the 4th most powerful rocket in the world. This added power allows the rocket to be able to put 63,800 kg (140,660 lb) into low earth orbit, and 26,700 kg (58,860 lb) into geosynchronous orbit.
On February 6, 2018, at 20:45 UTC, the Falcon Heavy took off for the first time at Kennedy Space Center, Florida, from Pad 39A. On this mission, "Falcon Heavy Test flight", SpaceX decided to use Elon Musk's car (a 2008 Tesla Roadster) as a dummy payload. This payload also included, below it, a plaque of the current SpaceX employees, as well as camera mounts to stream a live feed of the car on youtube.
Dragon[change | change source]
The Dragon spacecraft is a cargo capsule designed to be filled with equipment and supplies for the astronauts on the ISS. The capsule is put on the Falcon 9 rocket (because the Dragon does not have big enough rockets to fly to space on its own) and flown into orbit. From orbit it separates from the boosters, then the capsule uses its own smaller rockets to get to the ISS. Then the capsule is filled up with old equipment, the results of scientific experiments, and garbage. It then reenters the Earth's atmosphere and parachutes into the ocean. The first flight of Dragon was in June 2010. The last flight was on 6 March 2020, with Dragon 2 scheduled for all future missions. 
Dragon 2[change | change source]
On May 29, 2014, SpaceX unveiled a prototype version of Dragon V2, which could hold both cargo and astronauts. Another feature that this upgraded version of Dragon, to protect the life of crew in the event of a failure of Falcon 9, it was fitted with SuperDraco thrusters, which would push the capsule away from the rocket. Cargo Dragon, a variant of V2, will replace the current version of dragon that can only hold cargo.
Rocket engines[change | change source]
Since SpaceX started in 2002, the company has created three types of rocket engines — Merlin and the retired Kestrel for launch vehicle propulsion, and the Draco control thrusters. SpaceX is currently working on two further rocket engines: SuperDraco and Raptor. Merlin is a family of rocket engines made by SpaceX for use on their rockets. The Merlin engine was originally designed for sea recovery and reuse. Kestrel is a Liquid Oxygen/Rocket fuel pressure-fed rocket engine and was used as the Falcon 1 rocket's second stage main engine. Both names for the Merlin and Kestrel engines come from species of North American falcons: the kestrel and the merlin.
Draco are hypergolic liquid-propellant rocket engines that utilize monomethyl hydrazine fuel and nitrogen tetroxide oxidizer. Each Draco thruster creates 400 newtons (90 lbf) of thrust. They are used as reaction control system (RCS) thrusters on the Dragon spacecraft. SuperDraco engines are a much more powerful version of the Draco thrusters, which were initially meant to be used as landing and a way to get the capsule away in an emergency on the version 2 Dragon spacecraft, Dragon 2. The concept of using these SuperDraco engines for landing was canceled in 2017 when it was decided to perform a traditional parachute descent and landing in the sea.
Raptor is a new family of methane-fueled engines to be used in its future Starship rockets. Testing versions were test fired in late 2016. On April 3, 2019, SpaceX conducted a successful test in which the engine was started but the rocket was held down in Texas on its Starhopper vehicle, which ignited the engine while the vehicle remained attached to the ground. On July 24, 2019 SpaceX conducted a successful test flight of 20 meters up of its Starhopper test vehicle. On the 28th August 2019 SpaceX's Starhopper prototype conducted a successful test flight of 150-meters.
Research and Development[change | change source]
Reusability[change | change source]
SpaceX's secondary mission is to reuse rockets, similarly to a plane. It first began to test reusability with a prototype called Grasshopper in 2012, as well as controlled soft landings into the water during Falcon 9 launches. In 2014, Grasshopper was replaced by F9R, which was an upgraded version of grasshopper included retractable landing gear and 3 engines, compared to Grasshopper's single engine. Falcon 9 was landed in December on a ground pad, followed by a landing on a drone ship the next year. Currently, SpaceX has landed successfully 48 boosters. Dragon capsules, as well as farings, are also being reused. Reusing parts of rockets greatly reduce costs.
Satellite Internet[change | change source]
In January 2015, SpaceX CEO Elon Musk announced the development of a new satellite constellation to provide internet service to the world. In June 2015 the company asked the federal government for permission to begin testing for a project that aims to build a web of 4,425 satellites capable of beaming the Internet to the entire globe, including remote regions which currently do not have Internet access. The Internet service would use 4,425 cross-linked communications satellites in 1,100 km orbits. It started to be made in 2015, and testing satellites were launched on the SpaceX PAZ mission in 2017. Initial operation of the constellation could begin as early as 2020. SpaceX filed with the US regulatory authorities plans to field a constellation of an additional 7,518 satellites in non-geosynchronous orbits to provide communications services" in an Called the "V-band low-Earth-orbit (VLEO) constellation", it would consist of "7,518 satellites to follow the [earlier] proposed 4,425 satellites that would function in Ka-band and Ku-band". In February 2019, SpaceX formed a sibling company, SpaceX Services, Inc., to license the creation and launch of up to 1,000,000 fixed satellite earth stations that will communicate with its Starlink system. In May 2019, SpaceX launched the first batch of 60 satellites aboard a Falcon 9 from Cape Canaveral, FL.
Starship and SuperHeavy[change | change source]
SpaceX is creating a super-heavy lift rocket, Starship. Starship is a rocket with two parts that can be used over and over again. It is planned to replace all of the company's existing rockets by the early 2020s.
SpaceX initially envisioned a 12-meter-diameter Interplanetary Transport System (ITS) concept in 2016 which was only planned for Mars travel and other interplanetary uses. In 2017, SpaceX designed a smaller 9-meter-diameter "Big Falcon Rocket" to replace all of SpaceX launch capabilities— Earth-orbit, lunar-orbit, interplanetary missions, and potentially, even earth transit—but do so on a fully reusable set of vehicles with a lower cost structure. A large portion of the components on Starship are made of 301 stainless steel. Private passenger Yusaku Maezawa has contracted to fly around the Moon in Starship in 2023.
Musk's long term vision for the company is the creation of technology and means suitable for human colonization on Mars. He has expressed his interest in someday traveling to the planet, stating "I'd like to die on Mars, just not on impact." A rocket every two years or so could provide a base for the people arriving in 2025 after a launch in 2024. According to Steve Jurvetson, Musk believes that by 2035 at the latest, there will be thousands of rockets flying a million people to Mars, in order to enable a self-sustaining human colony.
Contracts[change | change source]
NASA contracts[change | change source]
COTS[change | change source]
In 2006, NASA said that SpaceX had won a NASA Commercial Orbital Transportation Services (COTS) Phase 1 contract to show cargo delivery to the ISS, with a possible contract option for crew flight. This contract, designed by NASA to provide "seed money" through Space Act Agreements for developing new space opportunities, NASA paid SpaceX $396 million to work on the cargo configuration of the Dragon spacecraft, while SpaceX spent more than $500 million to develop the Falcon 9 launch vehicle. These Space Act Agreements have been shown to have saved NASA millions of dollars in development costs, making rocket development ~4-10 times cheaper than if produced by NASA alone.
In December 2010, the launch of the COTS Demo Flight 1 mission, SpaceX became the first private company to successfully launch, orbit and recover a spacecraft. Dragon was successfully put into orbit, circled the Earth twice, and then made a controlled burn for a water landing in the Pacific Ocean. With Dragon's safe recovery, SpaceX became the first private company to launch, orbit, and recover a spacecraft; prior to this mission, only government agencies had been able to recover orbital spacecraft.
Commercial cargo[change | change source]
Commercial Resupply Services (CRS) are a group of contracts given by NASA from 2008 to 2016 for delivery of cargo and supplies to the ISS on commercially operated spacecraft. The first CRS contracts were signed in 2008 and gave $1.6 billion to SpaceX for 12 cargo sending missions, covering deliveries to 2016. SpaceX CRS-1, the first of the 12 planned resupply missions, launched in October 2012, achieved orbit, connected to and remained on station for 20 days, before re-entering the atmosphere and splashing down in the Pacific Ocean. CRS missions have flown approximately twice a year to the ISS since then. In 2015, NASA extended the Phase 1 contracts by ordering an additional three resupply flights from SpaceX. After further extensions late in 2015, SpaceX is currently scheduled to fly a total of 20 missions. A second group of contracts (known as CRS2) were solicited and proposed in 2014. They were given in January 2016, for cargo transport flights beginning in 2019 and expected to last through 2024.
Commercial crew[change | change source]
The Commercial Crew Development (CCDev) program intends to develop commercially operated spacecraft that are capable of delivering astronauts to the ISS. SpaceX did not win a Space Act Agreement in the first round (CCDev 1), but during the second round (CCDev 2), NASA awarded SpaceX with a contract worth $75 million to further develop their launch escape system, test a crew accommodations mock-up, and to further progress their Falcon/Dragon crew transportation design. The CCDev program later became Commercial Crew Integrated Capability (CCiCap), and in August 2012, NASA announced that SpaceX had been awarded $440 million to continue development and testing of its Dragon 2 spacecraft.
In September 2014, NASA chose SpaceX and Boeing as the two companies that will be funded to develop systems to transport U.S. crews to and from the ISS. SpaceX won $2.6 billion to complete and certify Dragon 2 by 2017. The contracts include at least one crewed flight test with at least one NASA astronaut aboard. Once Crew Dragon achieves NASA certification, the contract requires SpaceX to conduct at least two, and as many as six, crewed missions to the space station. In early 2017, SpaceX was awarded four additional crewed missions to the ISS from NASA to shuttle astronauts back and forth. In early 2019, SpaceX successfully conducted a test flight of Crew Dragon, which it docked (instead of Dragon 1's method of berthing using Canadarm 2) and then splashed down in the Atlantic Ocean.
In January 2020, SpaceX conducted an In-Flight Abort Test, which demonstrated the ability to get away from a rocket in case of a problem. Following the test, Elon Musk stated that a flight with astronauts on it could possibly be from Early April to late June.
References[change | change source]
- "California Business Search (C2414622 – Space Exploration Technologies Corp)". California Secretary of State. Retrieved 5 May 2018.
- Fred Lambert (17 November 2016). "Elon Musk's stake in SpaceX is actually worth more than his Tesla shares". Retrieved 1 March 2017.
- Foust, Jeff (16 November 2017). "Shotwell: I was the 7th employee at SpaceX. We're up to about 7,000 now. #NewSpaceEurope". Retrieved 13 January 2019.
- "Gwynne Shotwell: Executive Profile & Biography". Bloomberg. Retrieved 1 March 2017.
- W.J. Hennigan (7 June 2013). "How I Made It: SpaceX exec Gwynne Shotwell". Los Angeles Times. Retrieved 1 March 2017.
- SpaceX Tour – Texas Test Site. spacexchannel. 11 November 2010. Retrieved 23 May 2012.
- "SpaceX NASA CRS-6 PressKit Site" (PDF). 12 April 2015. Retrieved 13 April 2015.
- Chang, Kenneth (25 May 2012). "Space X Capsule Docks at Space Station". New York Times. Retrieved 31 March 2013.
- Rowe, Aaron (14 July 2009). "SpaceX Launch Successfully Delivers Satellite Into Orbit". Wired Science. Retrieved 31 March 2013.
- Miles O'Brien (June 1, 2012). "Elon Musk Unedited". Archived from the original on March 23, 2017. Retrieved March 1, 2017.
- John Carter McKnight (25 September 2001). "Elon Musk, Life to Mars Foundation". Space Frontier Foundation. Retrieved 1 March 2017.
- Elon Musk (30 May 2009). "Risky Business". IEEE Spectrum. Retrieved 1 March 2017.
- Elon Musk on dodging a nervous breakdown. YouTube. 20 April 2015. Retrieved 1 March 2017.
- Andrew Chaikin (January 2012). "Is SpaceX Changing the Rocket Equation?". Air & Space Smithsonian. Retrieved 1 March 2017.
- Ashlee Vance (14 May 2015). "Elon Musk's space dream almost killed Tesla". Bloomberg. Retrieved 1 March 2017.
- "How Steve Jurvetson Saved Elon Musk". Business Insider. 14 September 2012. Retrieved 4 June 2015.
- "SpaceX". NASA Space Academy at Glenn. Archived from the original on 8 June 2015. Retrieved 4 June 2015.
- Elon's SpaceX Tour – Engines. YouTube. 11 December 2010. Retrieved 1 March 2017.
- SpaceX and Daring to Think Big – Steve Jurvetson. YouTube. 28 January 2015. Retrieved 4 June 2015.
- Michael Belfiore (1 September 2009). "Behind the Scenes With the World's Most Ambitious Rocket Makers". Popular Mechanics. Retrieved 1 March 2017.
- Foust, Jeff (14 November 2005). "Big plans for SpaceX". The Space Review.
- SpaceX (2008-07-10). "Diane Murphy joins SpaceX as Vice President of Marketing and Communications". Press release. Archived from the original on 2010-07-13. https://web.archive.org/web/20100713163321/http://www.californiaspaceauthority.org/html/government_pages/pr080714-1.html. Retrieved 2019-06-16.
- Messier, Doug (16 October 2013). "ISPCS Morning Session: Gwynne Shotwell of SpaceX". Retrieved 7 December 2015.
Gwynne Shotwell says that SpaceX is now up to about 3,800 employees, counting contractors working for the company. ... 600 more people to hire in next couple months. Finding good software people the hardest skills to fill.
- "SpaceX's Redmond effort 'very speculative'". Seattle Times. 7 November 2015. Retrieved 1 March 2017.
- Gwynne Shotwell (3 February 2016). Gwynne Shotwell comments at Commercial Space Transportation Conference. Commercial Spaceflight. Event occurs at 2:43:15–3:10:05. Retrieved 4 February 2016.
- de Selding, Peter B. (14 April 2017). "Blue Origin's older than SpaceX in more ways than one". Space Intel Report. Retrieved 15 April 2017.
- Crosbie, Jackie (28 September 2016). "Elon Musk Explains Why SpaceX Only Hires Americans".
- Web archive of Spacex.com, July 4, 2004
- SpaceX Falcon 9 Data SheetSpace Launch Report
- Grush, Loren (7 March 2020). "SpaceX launches the last flight of its original Dragon cargo capsule". The Verge. Retrieved 8 March 2020.
- Gray, Tyler (6 March 2020). "SpaceX launches final Dragon 1 mission to the ISS". NASASpaceFlight.com. Retrieved 8 March 2020.
- Wilkins, Alasdair. "Tesla, Falcon 9, Heart of Gold: How Elon Musk Names His Inventions". Inverse. Retrieved 2 February 2019.
- SpaceX (December 9, 2008). "SpaceX Draco Thruster Performs Long-Duration Firing and Restart". Press release. Archived from the original on April 12, 2017. https://web.archive.org/web/20170412033357/http://www.spacex.com/press/2012/12/19/spacex-draco-thruster-performs-long-duration-firing-and-restart. Retrieved March 1, 2017.
- "Falcon 9 Launch Vehicle Payload User's Guide, 2009" (PDF). SpaceX. 2009. Archived from the original on May 3, 2012. Retrieved March 1, 2017.CS1 maint: bot: original URL status unknown (link)
- Colangelo, Anthony. "Farewell, Red Dragon". Main Engine Cut Off. Retrieved 1 February 2019.
- NSF, Chris B.- (25 July 2019). "Spacex official livestream "Starhopper is a test vehicle that SpaceX is using to help develop its Starship Launch System"". @NASASpaceflight. Retrieved 7 September 2019.
- "SpaceX performs first test of Raptor engine". SpaceNews.com. 26 September 2016. Retrieved 28 April 2017.
- Grush, Loren (3 April 2019). "SpaceX just fired up the engine on its test Starship vehicle for the first time". The Verge. Retrieved 4 April 2019.
- "Big News! SpaceX's Starhopper Test Vehicle Completes First Free Flight!".
- Business, Jackie Wattles, CNN. "SpaceX's Starhopper prototype soars in 150-meter 'hop test'". CNN. Retrieved 28 August 2019.
- Cecilia Kang, Christian Davenport (9 June 2015). "SpaceX founder files with government to provide Internet service from space". The Washington Post. Retrieved 1 March 2017.
- Jeff Stone (10 June 2015). "Elon Musk's SpaceX Plans To Launch 4,000 Satellites, Broadcasting Internet To Entire World". International Business Times. Retrieved 1 March 2017.
- Caleb Henry (2 March 2017). "FCC gets five new applications for non-geostationary satellite constellations". Space News. Retrieved 1 March 2017.[permanent dead link]
- SpaceX Services Application for Blanket-licensed Earth stations, SES-LIC-INTR2019-00217, SpaceX, 1 February 2019, accessed 9 February 2019.
- "Falcon 9 launches first Starlink mission – heaviest payload launch by SpaceX to date – NASASpaceFlight.com". Retrieved 4 July 2019.
- "Elon Musk's Mars dream hinges on a giant new rocket". Engadget. Retrieved 29 March 2018.
- "SpaceX signs first private passenger to fly around the moon". Reuters. Retrieved 14 September 2018.
- "SpaceX reveals mystery moon passenger, and he's a billionaire". CNET. Retrieved 18 September 2018.
- "SpaceX Upcoming Missions". Spacexnow.com. Retrieved 13 October 2018.
- Daniel Terdiman (9 March 2013). "Elon Musk at SXSW: 'I'd like to die on Mars, just not on impact'". CNET. Retrieved 1 March 2017.
- Alex Hern (2 June 2016). "Elon Musk: 'Chances are we're all living in a simulation'". The Guardian. Retrieved 1 March 2017.
- Sarah Fecht (2 June 2016). "Elon Musk Wants To Put Humans On Mars By 2025". Popular Science. Retrieved 1 March 2017.
- "Here's Why Investor Steve Jurvetson Saved Elon Musk's Space Dreams". Business Insider. Retrieved 2 March 2018.
- Dennis Stone, "NASA's Approach to Commercial cargo and Crew Transportation, Acta Astronautica 63, No. 1-4 (2008):192-97.</ref name="SpaceX presser 20060818">SpaceX (August 18, 2006). "SpaceX wins NASA COTS contract to demonstrate cargo delivery to Space Station with option for crew transport". Press release. Archived from the original on February 16, 2017. https://web.archive.org/web/20170216160324/http://www.spacex.com/press/2012/12/19/spacex-wins-nasa-cots-contract-demonstrate-cargo-delivery-space-station. Retrieved March 1, 2017.
- AtlanticCouncil (4 June 2014), Discussion with Gwynne Shotwell, President and COO, SpaceX, retrieved 29 March 2018
- "Mission Status Center". SpaceFlightNow. Retrieved 1 March 2017.
- Brendan McGarry (May 25, 2012). "SpaceX Becomes First Company to Dock Ship at Space Station". The San Francisco Chronicle. Archived from the original on May 26, 2012. Retrieved March 1, 2017.CS1 maint: bot: original URL status unknown (link)
- Kenneth Chang (22 May 2012). "Big Day for a Space Entrepreneur Promising More". The New York Times. Retrieved 1 March 2017.
- SpaceX (December 23, 2008). "NASA selects SpaceX's Falcon 9 booster and Dragon spacecraft for cargo resupply services to the International Space Station". Press release. Archived from the original on January 9, 2014. https://web.archive.org/web/20140109000000/http://www.spacex.com/press/2012/12/19/nasa-selects-spacexs-falcon-9-booster-and-dragon-spacecraft-cargo-resupply. Retrieved March 1, 2017.
- "NASA Celebrates Dragon's Return". NASA. Retrieved 1 March 2017.
- Chris Bergin (3 March 2015). "NASA lines up four additional CRS missions for Dragon and Cygnus". NASASpaceFlight. Retrieved 1 March 2017.
- Jason Rhian (27 September 2014). "NASA continues Commercial "push" with CRS extension". Spaceflight Insider. Retrieved 1 March 2017.
- Peter B. de Selding (24 February 2016). "SpaceX wins 5 new space station cargo missions in NASA contract estimated at $700 million". SpaceNews. Retrieved 1 March 2017.
- "Private Space Taxi's Crew Escape System Passes Big Hurdle". Space.com. 28 October 2011. Retrieved 1 March 2017.
- "SpaceX Proposal for Commercial Crew Development Round 2" (PDF). NASA. 2011. Archived from the original (PDF) on June 12, 2012. Retrieved March 19, 2012.
- Frank, Jr. Morring (25 April 2011). "Five Vehicles Vie For Future Of U.S. Human Spaceflight". Aviation Week. Retrieved 1 March 2017.
- "NASA Announces Next Steps in Effort to Launch Americans from U.S. Soil". NASA. August 3, 2012. Archived from the original on March 19, 2017. Retrieved March 1, 2017.
- Zach Rosenberg (2 March 2012). "SpaceX finishes crucial dress rehearsal before space station launch". FlightGlobal. Retrieved 1 March 2017.
- "NASA Chooses American Companies to Transport U.S. Astronauts to International Space Station". NASA. 16 September 2014. Retrieved 1 March 2017.
- "NASA awards SpaceX with crew missions to International Space Station". www.teslarati.com. Retrieved 29 March 2018.
- "SpaceX rocket ship blasts off on historic flight to International Space Station". Deutsche Welle. Retrieved 31 May 2020.
- Clark, Stephen. "NASA astronauts launch from U.S. soil for first time in nine years – Spaceflight Now". Spaceflight Now. Retrieved 31 May 2020.
- Making History: NASA and SpaceX Launch Astronauts to Space! (YouTube). Retrieved 31 May 2020.