<div class="text-justify">In 2011 the last manned American spacecraft took off. Since then NASA astronauts have only been able to access the space using Russian Soyuz spacecraft paying a sum that has gradually increased (almost a seat of a spaceship in 2018 has gone to NASA for 82 million dollars). But this year everything must change. If NASA sells with it in 2018, it clears for the first time the two ships that must return to the United States the autonomy to carry out their astronauts to the International Space Station (ISS): the CST-100 Starliner of Boeing and the Dragon 2 of SpaceX. Finally, after several years of delays, his first missions are scheduled for August of this year.
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*Dragon 2 (left) and CST-100 Starliner (NASA).*</center>
Boeing is building a total of three Starliner capsules - called in a very original way as Spacecraft 1, 2 and 3 (SC1, SC2 and SC3) - that will be reused after each mission, in addition to a test vehicle. The Starliner will be the first US capsule to land on dry land instead of landing in the ocean, a measure introduced to facilitate the rescue of the crew and facilitate reuse. For this the capsule has been equipped with a system of airbags that will cushion the impact against the surface. By the end of October 2017, eleven landing tests out of a total of fourteen had been carried out at NASA's Langley Center. Last year the capsule was also released from a helicopter to check the proper functioning of airbags and parachutes. Just in case, the parachute system was subjected to another test in which they were deployed at the height corresponding to a real mission, so it was necessary to raise a model of the capsule using a hot air balloon.</div>
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*Boeing CST-100 Starliner capsule (Boeing).*</center>
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*The Starliner during one of the landing tests at Langley (NASA).*
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https://www.youtube.com/watch?v=Ysmbj4jy6lM
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https://www.youtube.com/watch?v=WWFgfUyqIxU
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<div class="text-justify">After the unforeseen problems that appeared a few years ago regarding the bad aerodynamic behavior of the capsule once integrated with the Atlas V N22 rocket (an Atlas V 412 without a cap), Boeing decided to introduce a stabilizer ring around the capsule and a ' skirt 'on the back of the vehicle. The wind tunnel tests of this configuration have been satisfactory. The Starliner will use an Atlas V launcher with a second stage Centaur equipped with two engines, unlike the normal versions, which only have one engine. In early January of this year the Starliner passed the DCR (Design Certification Review), a necessary step that shows that the ship is ready to enter service. Starliner capsules are prepared in the C3PF (Commercial Crew and Cargo Processing Facility) building of the Kennedy Space Center. This building was formerly known as OPF-3 and was previously dedicated to preparing the space shuttle between each flight.</div>
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*Assembly of the first Starliner that will travel to space with the airbags already installed (Boeing).*</center>
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*The interior of the Starliner capsule with the IVA pressure suits (Boeing).*</center>
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<div class="text-justify">The SLC-41 ramp from where the Starliner ships will take off has already been equipped with the catwalk for the crew and the characteristic "white room" to prepare the astronauts before entering the vehicle. The escape system of the ramp has also been tested in case of emergency, consisting of a zip line that will allow evacuation of astronauts to a safe distance if a problem arises before takeoff. However, the Starliner still has to overcome its most important test before the first mission: to check the operation of the exhaust system, consisting of four engines of 8.2 tons of thrust in total located in the service module. These engines will also function as a propulsion system once in orbit. This test, called PAT (Pad Abort Test), will take place at the NASA facilities in White Sands (New Mexico).</div>
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*Gateway to the capsule for the SLC-41 (Boeing) ramp.*</center>
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*Emergency escape system of the Starliner ramp (Boeing).*</center>
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*Rocket and launch ramp of the Starliner (Boeing).*</center>
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<div class="text-justify">The first unmanned mission of the Starliner, the Boe-OFT (Boeing Orbital Flight Test) is scheduled for the end of August and will last two weeks during which all the systems of the ship will be tested (this flight will also be the mission AV-080 of Atlas V). The capsule will automatically be coupled to the PMA-2 of the Harmony module of the space station and the ISS crew will inspect its interior. The first manned mission, Boe-CFT (Boeing Crewed Flight Test), will take place officially in November 2018 before the first flight with SpaceX's Dragon 2 astronauts and will also be extended for two weeks. However, it is common knowledge that the first manned missions of the two vehicles will not take place before December 31, 2018. In any case, these dates are very provisional and will depend on the behavior of the ships in the previous certification flights.</div>
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*Test vehicle Structural Test Article (STA) of the Starliner (Boeing).*</center>
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*Launching configuration of the Starliner with the aerodynamic skirt (Boeing).*</center>
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<div class="text-justify">The first regular mission to the ISS will be the CTS-1 and must take off in May 2019. The ship will remain attached to the station until November and will carry two or four astronauts. In case the Starliner and the Dragon 2 are not ready for next year NASA has already ordered Roscosmos seats for their astronauts in two additional Soyuz spacecraft. If he had not done so, he risks running out of astronauts on the space station, a logically unacceptable scenario. For the time being, and like the Dragon 2, the Starliner will carry a maximum of four crew on its missions to the ISS, although it has been designed to carry up to seven people.</div>
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*Launching configuration of the Starliner with the aerodynamic skirt (Boeing).*</center>
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*CST-100 Starliner (Boeing).*</center>
<div class="text-justify">As for SpaceX, the development of the Dragon 2 (Dragon V2) continues at a good pace, although the details available are much scarcer than in the case of the Starliner. In 2015 SpaceX already carried out the PAT test of the exhaust system, a test that presented several problems and potential risks that NASA did not like at all. It is assumed that since then the company of Elon Musk has already corrected the possible failures of the system, formed by four Super Draco propellers based on hypergolic fuels. The fact that this emergency system uses toxic fuels and surrounds the capsule instead of being located above (Soyuz) or below (Starliner) of the crew compartment has been one of the main sources of conflict between SpaceX and NASA on safety matter. Despite the pressures of SpaceX, the space agency flatly refused to let Dragon 2 use this system to carry out propelled landings, which has forced SpaceX to abandon the possibility of landing by jet propulsion in the near future (and , by the way, has caused the cancellation of the unmanned Martian ship project Red Dragon). In April of this year, a new test of the flight escape system will be held, IFA (In-Flight Abort).</div>
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*Manned Dragon 2 ship under construction (NASA).*</center>
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*The Dragon 2 during the test of the exhaust system in 2015 (SpaceX).*</center>
<div class="text-justify">For this reason during 2017 SpaceX has had to re-check the parachute system intensively (at the end of last year it had already carried out eight tests). In addition, specific tests have been carried out on the propulsion system of the Falcon 9 (the Merlin 1D and MVac Full Thrust engines) to verify that they are suitable for manned flights. The safety of the new version of Falcon 9, Block 5, which must fly for the first time this February, has also been studied. Last year SpaceX presented the suit of pressure that the astronauts of the Dragon 2 will take, although it did not give any technical details of it. However, SpaceX successfully conducted a test of the crew inside the capsule with the diving suits on.</div>
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*Dragon V2 spacecraft manned SpaceX with his diving suit (SpaceX).*</center>
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*Test of the parachute system of the Dragon 2 in the Delamar dry lake (NASA).*</center>
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https://www.youtube.com/watch?v=4PG438XSarg
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<div class="text-justify">Like Boeing, SpaceX is building three Dragon 2 capsules - and a test vehicle (Qualification Module) - for the first three missions. These capsules will be reused later, although it is not clear if you plan to build any more. Now that we know that the Dragon 2 will land in the ocean in all its missions instead of landing on the mainland, NASA has insisted on the training of rescue of the crew on the high seas, for which a model of the ship destined for this purpose.</div>
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*Pressurized compartment of the Dragon 2 and its thermal shield (SpaceX).*</center>
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*Dragon model for rescue tests in the ocean.*</center>
<div class="text-justify">The Dragon 2 will take off from the 39A ramp of the Kennedy Space Center through a Falcon 9 Block 5. The ramp is ready, although SpaceX must install the crew access gateway in the coming weeks. The first unmanned Dragon 2 mission will be Demo 1 (SpX Demo-1) and is scheduled for August. Like the inaugural flight of the Starliner, the ship's systems will be tested for two weeks and will be coupled to the PMA-2 port of the ISS. Officially the first manned mission, Demo 2, will be in December of this year after the first manned flight of the Starliner, but we have already said that it is likely to be delayed to 2019 and it is very possible that SpaceX forward to Boeing in the race for putting a person in space. The Demo 2 mission will last two weeks and will take two astronauts, while the first operational mission, Crew-1, will transport between two and four crew members, remaining attached to the ISS between April and June 2019.</div>
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*Gateway of the crew on ramp 39A (not yet installed).*</center>
<div class="text-justify">However, the main problem facing the Dragon 2 of SpaceX is security. In a recent report of the ASAP (Aerospace Safety Advisory Panel) commissioned by the US Congress, the risks presented by the second stage of Falcon 9 for manned flights are indicated. In 2016 the Falcon 9 F9-29 exploded on the ramp due to a defect in one of the helium tanks, called COPV (Composite Overwrap Pressure Vessel), used to pressurize the propellant tanks. Needless to say, the ruling blew up all the alarms at NASA. SpaceX has worked on a new version of the COPV for the second stage, but from what you see NASA is not entirely convinced. Another worrying point pointed out by the ASAP panel is SpaceX's plan to load the rocket with liquid oxygen at a very low temperature - to increase its density - with the crew inside the ship. The panel considers that it is a high-risk practice that, along with the unknowns of the helium tanks, could justify delaying the certification of the Dragon 2 for manned flights until beyond 2019 if necessary, as long as Boeing puts in service the Starliner and allow access to the US astronaut space.
So place your bets. Who will fly first? Boeing or SpaceX? And most importantly, which of the two companies will you take before astronauts?</div>
https://www.youtube.com/watch?v=UVnrb_Z2Wnk
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#### References:
https://oiir.hq.nasa.gov/asap/documents/2017_ASAP_Annual_Report.pdf