Reusable space: promising projects of US spacecraft
21 July 2011, the American spacecraft Atlantis made its last landing, which put an end to the long and interesting Space Transportation System program. For a variety of technical and economic reasons, it was decided to discontinue the operation of the Space Shuttle system. However, the idea of a reusable spacecraft was not abandoned. Currently, several similar projects are being developed at once, and some of them have already managed to show their potential.
The Space Shuttle reusable spacecraft project pursued several main objectives. One of the main was the reduction of the cost of the flight and preparation for it. The possibility of multiple use of the same ship in theory gave certain advantages. In addition, the characteristic technical appearance of the entire complex has significantly increased the permissible dimensions and weight of the payload. A unique feature of the STS was the ability to return the spacecraft to Earth within its own cargo compartment.
The last launch of the ship Altantis, 8 July 2011 g. Photo by NASA
However, during the operation it was found that far from all the tasks were accomplished. So, in practice, the preparation of the ship for the flight was too long and expensive - according to these parameters, the project did not fit into the initial requirements. In a number of cases, the reusable ship couldn’t replace "conventional" launch vehicles. Finally, the gradual moral and physical obsolescence of technology led to the most serious risks for crews.
As a result, it was decided to terminate the operation of the Space Transportation System. The last 135 flight took place in the summer of 2011. Four available ships were written off and transferred to museums as useless. The most famous consequence of such decisions was the fact that the American space program for several years was left without its own manned spacecraft. Until now, astronauts have to fall into orbit with the help of Russian technology.
In addition, for an indefinite period, the entire planet was left without reusable systems in use. However, certain measures are already being taken. To date, American companies have developed several projects of reusable spacecraft of one kind or another. All new samples have, at a minimum, been put to the test. In the foreseeable future, they will also be able to enter full operation.
Boeing X-37
The main component of the STS complex was an orbital plane. This concept is currently used in Boeing’s X-37 project. Back in the late nineties, Boeing and NASA began to study the themes of reusable ships capable of being in orbit and flying in the atmosphere. At the beginning of the last decade, these works led to the launch of the X-37 project. In 2006, a prototype of a new type reached flight tests with discharge from an aircraft carrier.
The device Boeing X-37B in the rocket fairing. Photo of US Air Force
The program was of interest to the US Air Force, and since 2006 has already been implemented in their interests, although with some assistance from NASA. According to official data, the Air Force wants to get a promising orbital aircraft capable of taking various loads into space or performing various experiments. According to various estimates, the current X-37B project can be used in other missions, including those related to reconnaissance or carrying out full-fledged combat work.
The first space flight of the X-37B took place in the 2010 year. At the end of April, the Atlas V launch vehicle brought the device to a predetermined orbit, where he stayed 224 of the day. Landing "in an airplane" took place in early December of the same year. In March of the following year, the second flight began, which lasted until June of the 2012. In December, the next launch took place, and the third landing was carried out only in October 2014. From May 2015 to May 2017, the experienced X-37B made its fourth flight. 7 last September began the next test flight. When it is completed - not specified.
According to the few official data, the purpose of the flights is to study the operation of new technology in orbit, as well as conducting various experiments. Even if experienced X-37B and solve military problems, the customer and the contractor do not disclose such information.
In its current form, the Boeing X-37B product is a rocket plane with a characteristic appearance. It has a large fuselage and medium-sized planes. Used rocket engine; control is carried out by automation or by commands from the ground. According to known data, a cargo compartment is provided in the fuselage with a length of more than 2 m and a diameter of more than 1 m, which can accommodate up to 900 kg of payload.
Right now, an experienced X-37B is in orbit and solves problems. When he returns to Earth is unknown. Information on the future course of the pilot project is also not specified. Apparently, the new messages about the most interesting development will appear not earlier than the next landing of the prototype.
SpaceDev / Sierra Nevada Dream Chaser
Another version of the orbital plane is the SpaceDev Dream Chaser spacecraft. This project was developed from 2004 year to participate in the program NASA Commercial Orbital Transportation Services (COTS), but could not pass the first stage of selection. However, the development company soon agreed to cooperate with the United Launch Alliance, which was ready to offer its Atlas V launch vehicle. In 2008, SpaceDev became part of the Sierra Nevada corporation, and soon after received additional funding to create its orbital the aircraft. Later, an agreement with Lockheed Martin appeared on the joint construction of experimental equipment.
An experienced orbital plane Dream Chaser. NASA Photos
In October, the 2013, the flight prototype of the Dream Chaser, was dropped from a helicopter carrier, after which it switched to a flight planner and made a horizontal landing. Despite the failure during landing, the prototype confirmed the calculated characteristics. Later on, some other tests were performed on the stands. According to their results, the project was finalized, and in 2016, the construction of a prototype for space flights began. In the middle of last year, NASA, Sierra Nevada and ULA signed an agreement to conduct two orbital flights in 2020-21.
Not so long ago, the developers of the Dream Chaser machine received permission to launch at the end of 2020. Unlike a number of other modern developments, the first space mission of this ship will be carried out with a real load. The ship will have to deliver certain cargoes to the International Space Station.
In its current form, the Sierra Nevada / SpaceDev Dream Chaser reusable spacecraft is a plane of characteristic appearance that looks like some American and foreign designs. The machine has a total length of 9 m and is equipped with a delta wing spanning 7 m. For compatibility with existing launch vehicles, a folding wing will be developed in the future. The take-off mass is determined at the level of 11,34 tons. The Dream Chaser will be able to deliver 5,5 tons of cargo to the ISS and return to Earth before the 2 tons. and samples in separate experiments.
Spacex dragon
For a number of reasons, the idea of an orbital plane is currently not very popular among developers of new space technology. A reusable spacecraft of a “traditional” appearance, which is launched into orbit with the help of a launch vehicle and returning to Earth without using wings, is now considered to be more convenient and advantageous. The most successful development of this kind is the Dragon product from SpaceX.
SpaceX Dragon cargo ship (mission CRS-1) near the ISS. NASA Photos
The Dragon project was launched in 2006 and performed as part of the COTS program. The aim of the project was to create a spacecraft with the possibility of repeated launches and returns. The first version of the project involved the creation of a transport ship, and later on its basis it was planned to develop a manned modification. To date, the Dragon in the version of the "truck" has shown certain results, while the expected success of the manned version of the ship is constantly shifted in time.
The first demonstration launch of the Dragon transport ship took place at the end of 2010. After all the required improvements, NASA ordered a full-fledged launch of such a device in order to deliver cargo to the International Space Station. 25 May 2012 of the Year "Dragon" successfully docked with the ISS. Later, several new launches were carried out with the delivery of goods into orbit. The most important stage of the program was the launch of 3 June 2017 of the year. First time in stories the program was restarted the repaired ship. In December, another spacecraft, already flying to the ISS, went into space. With all the tests so far, Dragon products have made 15 flights.
In 2014, SpaceX announced the promising manned spacecraft Dragon V2. It was argued that this device, which represents the development of an existing truck, would be able to deliver up to seven cosmonauts into orbit or return home. It was also reported that in the future the new ship could be used to fly around the moon, including with tourists on board.
As often happens with SpaceX projects, the timing of the implementation of the Dragon V2 project has shifted several times. So, due to delays with the supposed Falcon Heavy carrier, the date of the first tests moved to 2018 year, and the first manned flight gradually crawled to the 2019. Finally, a few weeks ago, the company-developer announced its intention to refuse certification of the new “Dragon” for manned flights. In the future, such tasks are supposed to be solved with the help of the reusable BFR system, which has not yet been created.
The Dragon transport ship has a full length of 7,2 m with a diameter of 3,66 m. Dry weight is 4,2 t. It is capable of delivering a payload of 3,3 tonnes to the ISS and returning to 2,5 tonnes of cargo. To accommodate certain cargoes, it is proposed to use a sealed compartment with a volume of 11 cubic meters and an unpressurized 14-cube volume. The compartment without sealing during descent is dumped and burned in the atmosphere, while the second cargo volume returns to Earth and lands on a parachute. For orbit correction, the device is equipped with 18 Draco type engines. The efficiency of the systems is provided by a pair of solar panels.
In developing the manned version of the Dragon, certain units of the base transport ship were used. At the same time, the hermetic compartment had to be considerably reworked to solve new problems. Also changed some other elements of the ship.
Lockheed martin orion
In 2006, NASA and Lockheed Martin agreed to create a promising reusable spacecraft. The project was named after one of the brightest constellations - Orion. At the turn of the decades, after the completion of part of the work, the leadership of the United States offered to abandon this project, but after long disputes it was saved. The work was continued and to date has led to certain results.
Promising ship Orion in the artist's view. NASA drawing
In accordance with the original concept, the Orion spacecraft was to be used in various missions. With it, it was supposed to deliver cargo and people to the International Space Station. Having received the appropriate equipment, he could go to the moon. The possibility of a flight to one of the asteroids or even to Mars was also studied. Nevertheless, the solution of such problems was attributed to the distant future.
According to the plans of the past decade, the Orion's first test launch was to take place in 2013. On 2014, they planned to launch with astronauts aboard. Flight to the moon could be carried out before the end of the decade. Subsequently, the schedule was adjusted. The first unmanned flight was transferred to the 2014 year, and the launch with the crew - to the 2017. Lunar missions moved to the twenties. By now, flights with the crew have been postponed for the next decade.
5 December 2014 of the year Orion’s first test launch took place. The ship with a payload simulator was launched into orbit by the Delta IV launch vehicle. A few hours after the start, he returned to Earth and splashed down in a given area. New launches have not yet been carried out. However, Lockheed-Martin and NASA specialists did not sit idle. Over the past few years, a number of prototypes have been built to carry out these or other tests in terrestrial conditions.
Just a few weeks ago, the construction of the first Orion ship for manned flight began. Its launch is scheduled for next year. The task of putting the ship into orbit will be assigned to the space launch vehicle Space Launch System. Completion of ongoing work will show the real prospects of the entire project.
The Orion project provides for the construction of a ship with a length of about 5 m and a diameter of about 3,3 m. A characteristic feature of this device is a large internal volume. Despite the installation of the necessary equipment and instruments, a little less than 9 cubic meters of free space remains inside the hermetic compartment, suitable for installing various devices, including the crew seats. The ship will be able to take on board up to six astronauts or a certain cargo. The total mass of the ship is determined at the level of 25,85 t.
Suborbital systems
Currently, there are several interesting programs that do not involve the removal of the payload on the Earth's orbit. Prospective samples of equipment from a number of US companies will be able to carry out only suborbital flights. This technique is supposed to be used for some research or in the development of space tourism. New projects of this kind are not considered in the context of the development of a full-fledged space program, but they are nonetheless of interest.
SpaceShipTwo suborbital spacecraft under the wing of a White Knight Two carrier aircraft. Photo Virgin Galactic / virgingalactic.com
The SpaceShipOne and SpaceShipTwo projects from Scale Composites and Virgin Galactic offer the construction of a complex comprising an aircraft carrier and an orbital aircraft. Since 2003, two types of equipment have performed a significant number of test flights, during which various features of the design and methods of work were worked out. It is expected that a SpaceShipTwo-type ship will be able to take on board up to six passenger passengers and raise them to a height of at least 100-150 km, i.e. above the lower boundary of outer space. Takeoff and landing should be carried out from the "traditional" airport.
Since the middle of the last decade, Blue Origin has been working on another version of the suborbital space system. She proposes to carry out similar flights with the help of a ligament of a launch vehicle and a ship as used in other programs. At the same time, both the rocket and the ship must be reusable. The complex was named New Shepard. With 2011, rockets and ships of a new type regularly perform test flights. Already managed to send a spacecraft to a height of more than 110 km, as well as to ensure the safe return of both the ship and the launch vehicle. In the future, the New Shepard system will have to become one of the novelties in the field of space tourism.
Reusable future
For three decades, since the early eighties of the last century, the main means of delivering people and goods into orbit in the arsenal of NASA has been the Space Transportation System / Space Shuttle complex. Due to moral and physical obsolescence, as well as due to the impossibility of obtaining all the desired results, the operation of the Shuttles was discontinued. Since 2011, the United States does not have workable reusable ships. Moreover, as long as they do not have their own manned spacecraft, as a result, astronauts have to fly on foreign technology.
Despite the cessation of operation of the Space Transportation System, the American space program does not abandon the very idea of reusable spacecraft. This technique is still of great interest and can be used in a variety of missions. At the moment, NASA and a number of commercial organizations are developing several promising spacecraft, both orbital planes and systems with capsules. At the moment, these projects are at different stages and show different successes. In the very near future, no later than the beginning of the twenties, most of the new developments will reach the stage of test or full-fledged flights, which will allow to re-examine the situation and draw new conclusions.
On the materials of the sites:
http://nasa.gov/
http://space.com/
http://globalsecurity.org/
https://washingtonpost.com/
http://boeing.com/
http://lockheedmartin.com/
http://spacex.com/
http://virgingalactic.com/
http://spacedev.com/
The Space Shuttle reusable spacecraft project pursued several main objectives. One of the main was the reduction of the cost of the flight and preparation for it. The possibility of multiple use of the same ship in theory gave certain advantages. In addition, the characteristic technical appearance of the entire complex has significantly increased the permissible dimensions and weight of the payload. A unique feature of the STS was the ability to return the spacecraft to Earth within its own cargo compartment.
The last launch of the ship Altantis, 8 July 2011 g. Photo by NASA
However, during the operation it was found that far from all the tasks were accomplished. So, in practice, the preparation of the ship for the flight was too long and expensive - according to these parameters, the project did not fit into the initial requirements. In a number of cases, the reusable ship couldn’t replace "conventional" launch vehicles. Finally, the gradual moral and physical obsolescence of technology led to the most serious risks for crews.
As a result, it was decided to terminate the operation of the Space Transportation System. The last 135 flight took place in the summer of 2011. Four available ships were written off and transferred to museums as useless. The most famous consequence of such decisions was the fact that the American space program for several years was left without its own manned spacecraft. Until now, astronauts have to fall into orbit with the help of Russian technology.
In addition, for an indefinite period, the entire planet was left without reusable systems in use. However, certain measures are already being taken. To date, American companies have developed several projects of reusable spacecraft of one kind or another. All new samples have, at a minimum, been put to the test. In the foreseeable future, they will also be able to enter full operation.
Boeing X-37
The main component of the STS complex was an orbital plane. This concept is currently used in Boeing’s X-37 project. Back in the late nineties, Boeing and NASA began to study the themes of reusable ships capable of being in orbit and flying in the atmosphere. At the beginning of the last decade, these works led to the launch of the X-37 project. In 2006, a prototype of a new type reached flight tests with discharge from an aircraft carrier.
The device Boeing X-37B in the rocket fairing. Photo of US Air Force
The program was of interest to the US Air Force, and since 2006 has already been implemented in their interests, although with some assistance from NASA. According to official data, the Air Force wants to get a promising orbital aircraft capable of taking various loads into space or performing various experiments. According to various estimates, the current X-37B project can be used in other missions, including those related to reconnaissance or carrying out full-fledged combat work.
The first space flight of the X-37B took place in the 2010 year. At the end of April, the Atlas V launch vehicle brought the device to a predetermined orbit, where he stayed 224 of the day. Landing "in an airplane" took place in early December of the same year. In March of the following year, the second flight began, which lasted until June of the 2012. In December, the next launch took place, and the third landing was carried out only in October 2014. From May 2015 to May 2017, the experienced X-37B made its fourth flight. 7 last September began the next test flight. When it is completed - not specified.
According to the few official data, the purpose of the flights is to study the operation of new technology in orbit, as well as conducting various experiments. Even if experienced X-37B and solve military problems, the customer and the contractor do not disclose such information.
In its current form, the Boeing X-37B product is a rocket plane with a characteristic appearance. It has a large fuselage and medium-sized planes. Used rocket engine; control is carried out by automation or by commands from the ground. According to known data, a cargo compartment is provided in the fuselage with a length of more than 2 m and a diameter of more than 1 m, which can accommodate up to 900 kg of payload.
Right now, an experienced X-37B is in orbit and solves problems. When he returns to Earth is unknown. Information on the future course of the pilot project is also not specified. Apparently, the new messages about the most interesting development will appear not earlier than the next landing of the prototype.
SpaceDev / Sierra Nevada Dream Chaser
Another version of the orbital plane is the SpaceDev Dream Chaser spacecraft. This project was developed from 2004 year to participate in the program NASA Commercial Orbital Transportation Services (COTS), but could not pass the first stage of selection. However, the development company soon agreed to cooperate with the United Launch Alliance, which was ready to offer its Atlas V launch vehicle. In 2008, SpaceDev became part of the Sierra Nevada corporation, and soon after received additional funding to create its orbital the aircraft. Later, an agreement with Lockheed Martin appeared on the joint construction of experimental equipment.
An experienced orbital plane Dream Chaser. NASA Photos
In October, the 2013, the flight prototype of the Dream Chaser, was dropped from a helicopter carrier, after which it switched to a flight planner and made a horizontal landing. Despite the failure during landing, the prototype confirmed the calculated characteristics. Later on, some other tests were performed on the stands. According to their results, the project was finalized, and in 2016, the construction of a prototype for space flights began. In the middle of last year, NASA, Sierra Nevada and ULA signed an agreement to conduct two orbital flights in 2020-21.
Not so long ago, the developers of the Dream Chaser machine received permission to launch at the end of 2020. Unlike a number of other modern developments, the first space mission of this ship will be carried out with a real load. The ship will have to deliver certain cargoes to the International Space Station.
In its current form, the Sierra Nevada / SpaceDev Dream Chaser reusable spacecraft is a plane of characteristic appearance that looks like some American and foreign designs. The machine has a total length of 9 m and is equipped with a delta wing spanning 7 m. For compatibility with existing launch vehicles, a folding wing will be developed in the future. The take-off mass is determined at the level of 11,34 tons. The Dream Chaser will be able to deliver 5,5 tons of cargo to the ISS and return to Earth before the 2 tons. and samples in separate experiments.
Spacex dragon
For a number of reasons, the idea of an orbital plane is currently not very popular among developers of new space technology. A reusable spacecraft of a “traditional” appearance, which is launched into orbit with the help of a launch vehicle and returning to Earth without using wings, is now considered to be more convenient and advantageous. The most successful development of this kind is the Dragon product from SpaceX.
SpaceX Dragon cargo ship (mission CRS-1) near the ISS. NASA Photos
The Dragon project was launched in 2006 and performed as part of the COTS program. The aim of the project was to create a spacecraft with the possibility of repeated launches and returns. The first version of the project involved the creation of a transport ship, and later on its basis it was planned to develop a manned modification. To date, the Dragon in the version of the "truck" has shown certain results, while the expected success of the manned version of the ship is constantly shifted in time.
The first demonstration launch of the Dragon transport ship took place at the end of 2010. After all the required improvements, NASA ordered a full-fledged launch of such a device in order to deliver cargo to the International Space Station. 25 May 2012 of the Year "Dragon" successfully docked with the ISS. Later, several new launches were carried out with the delivery of goods into orbit. The most important stage of the program was the launch of 3 June 2017 of the year. First time in stories the program was restarted the repaired ship. In December, another spacecraft, already flying to the ISS, went into space. With all the tests so far, Dragon products have made 15 flights.
In 2014, SpaceX announced the promising manned spacecraft Dragon V2. It was argued that this device, which represents the development of an existing truck, would be able to deliver up to seven cosmonauts into orbit or return home. It was also reported that in the future the new ship could be used to fly around the moon, including with tourists on board.
As often happens with SpaceX projects, the timing of the implementation of the Dragon V2 project has shifted several times. So, due to delays with the supposed Falcon Heavy carrier, the date of the first tests moved to 2018 year, and the first manned flight gradually crawled to the 2019. Finally, a few weeks ago, the company-developer announced its intention to refuse certification of the new “Dragon” for manned flights. In the future, such tasks are supposed to be solved with the help of the reusable BFR system, which has not yet been created.
The Dragon transport ship has a full length of 7,2 m with a diameter of 3,66 m. Dry weight is 4,2 t. It is capable of delivering a payload of 3,3 tonnes to the ISS and returning to 2,5 tonnes of cargo. To accommodate certain cargoes, it is proposed to use a sealed compartment with a volume of 11 cubic meters and an unpressurized 14-cube volume. The compartment without sealing during descent is dumped and burned in the atmosphere, while the second cargo volume returns to Earth and lands on a parachute. For orbit correction, the device is equipped with 18 Draco type engines. The efficiency of the systems is provided by a pair of solar panels.
In developing the manned version of the Dragon, certain units of the base transport ship were used. At the same time, the hermetic compartment had to be considerably reworked to solve new problems. Also changed some other elements of the ship.
Lockheed martin orion
In 2006, NASA and Lockheed Martin agreed to create a promising reusable spacecraft. The project was named after one of the brightest constellations - Orion. At the turn of the decades, after the completion of part of the work, the leadership of the United States offered to abandon this project, but after long disputes it was saved. The work was continued and to date has led to certain results.
Promising ship Orion in the artist's view. NASA drawing
In accordance with the original concept, the Orion spacecraft was to be used in various missions. With it, it was supposed to deliver cargo and people to the International Space Station. Having received the appropriate equipment, he could go to the moon. The possibility of a flight to one of the asteroids or even to Mars was also studied. Nevertheless, the solution of such problems was attributed to the distant future.
According to the plans of the past decade, the Orion's first test launch was to take place in 2013. On 2014, they planned to launch with astronauts aboard. Flight to the moon could be carried out before the end of the decade. Subsequently, the schedule was adjusted. The first unmanned flight was transferred to the 2014 year, and the launch with the crew - to the 2017. Lunar missions moved to the twenties. By now, flights with the crew have been postponed for the next decade.
5 December 2014 of the year Orion’s first test launch took place. The ship with a payload simulator was launched into orbit by the Delta IV launch vehicle. A few hours after the start, he returned to Earth and splashed down in a given area. New launches have not yet been carried out. However, Lockheed-Martin and NASA specialists did not sit idle. Over the past few years, a number of prototypes have been built to carry out these or other tests in terrestrial conditions.
Just a few weeks ago, the construction of the first Orion ship for manned flight began. Its launch is scheduled for next year. The task of putting the ship into orbit will be assigned to the space launch vehicle Space Launch System. Completion of ongoing work will show the real prospects of the entire project.
The Orion project provides for the construction of a ship with a length of about 5 m and a diameter of about 3,3 m. A characteristic feature of this device is a large internal volume. Despite the installation of the necessary equipment and instruments, a little less than 9 cubic meters of free space remains inside the hermetic compartment, suitable for installing various devices, including the crew seats. The ship will be able to take on board up to six astronauts or a certain cargo. The total mass of the ship is determined at the level of 25,85 t.
Suborbital systems
Currently, there are several interesting programs that do not involve the removal of the payload on the Earth's orbit. Prospective samples of equipment from a number of US companies will be able to carry out only suborbital flights. This technique is supposed to be used for some research or in the development of space tourism. New projects of this kind are not considered in the context of the development of a full-fledged space program, but they are nonetheless of interest.
SpaceShipTwo suborbital spacecraft under the wing of a White Knight Two carrier aircraft. Photo Virgin Galactic / virgingalactic.com
The SpaceShipOne and SpaceShipTwo projects from Scale Composites and Virgin Galactic offer the construction of a complex comprising an aircraft carrier and an orbital aircraft. Since 2003, two types of equipment have performed a significant number of test flights, during which various features of the design and methods of work were worked out. It is expected that a SpaceShipTwo-type ship will be able to take on board up to six passenger passengers and raise them to a height of at least 100-150 km, i.e. above the lower boundary of outer space. Takeoff and landing should be carried out from the "traditional" airport.
Since the middle of the last decade, Blue Origin has been working on another version of the suborbital space system. She proposes to carry out similar flights with the help of a ligament of a launch vehicle and a ship as used in other programs. At the same time, both the rocket and the ship must be reusable. The complex was named New Shepard. With 2011, rockets and ships of a new type regularly perform test flights. Already managed to send a spacecraft to a height of more than 110 km, as well as to ensure the safe return of both the ship and the launch vehicle. In the future, the New Shepard system will have to become one of the novelties in the field of space tourism.
Reusable future
For three decades, since the early eighties of the last century, the main means of delivering people and goods into orbit in the arsenal of NASA has been the Space Transportation System / Space Shuttle complex. Due to moral and physical obsolescence, as well as due to the impossibility of obtaining all the desired results, the operation of the Shuttles was discontinued. Since 2011, the United States does not have workable reusable ships. Moreover, as long as they do not have their own manned spacecraft, as a result, astronauts have to fly on foreign technology.
Despite the cessation of operation of the Space Transportation System, the American space program does not abandon the very idea of reusable spacecraft. This technique is still of great interest and can be used in a variety of missions. At the moment, NASA and a number of commercial organizations are developing several promising spacecraft, both orbital planes and systems with capsules. At the moment, these projects are at different stages and show different successes. In the very near future, no later than the beginning of the twenties, most of the new developments will reach the stage of test or full-fledged flights, which will allow to re-examine the situation and draw new conclusions.
On the materials of the sites:
http://nasa.gov/
http://space.com/
http://globalsecurity.org/
https://washingtonpost.com/
http://boeing.com/
http://lockheedmartin.com/
http://spacex.com/
http://virgingalactic.com/
http://spacedev.com/
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