The Advanced Space Transportation Program (ASTP) is a NASA program to intentionally advance current space transportation system technologies, and innovate novel technologies, through intense research efforts that are intended to culminate in regularizing the outer space environment decades from now. The intense efforts aim to accelerate scientific and technological breakthroughs. [1]
As NASA's core technology program for all space transportation, the Advanced Space Transportation Program at the Marshall Space Flight Center is advancing technologies that substantially increase the safety, and reliability of space transportation, as well as reduce the cost. Presently, it costs $10,000 to put a pound of payload in Earth orbit. NASA's goal is to reduce the cost of getting to space to hundreds of dollars per pound within 25 years and tens of dollars per pound within 40 years. [2]
The high cost of space transportation coupled with unreliability currently discourages access to space as an everyday environment. When space transportation becomes safe and affordable for ordinary people numerous possibilities and opportunities can be envisioned. The vision is guided by possibilities such as living and working in space, exploring new worlds, and vacationing off the Earth. In a similar context opportunities for business and pleasure are added multiples. [2]
Additionally, researchers at the Marshall Space Flight Center are intentionally advancing technologies from simple engines to exotic drives in order to fulfil each of the above objectives. [2]
The program's primary emphasis is on technologies for third generation reusable launch vehicles (RLVs) within an operational time frame of the year 2025, lowering the price tag to $100 per pound. As the next step beyond NASA's X-33 and X-34 flight demonstrators, these advanced technologies would move space transportation closer to an airline style of operations with horizontal takeoffs and landings, quick turnaround times and small ground support crews. [1] [2]
Third generation launch vehicles — beyond the Space Shuttle and "X" planes — are intended to use various cutting-edge technologies, such as advanced propellants that pack more energy into smaller tanks and result in smaller launch vehicles. Advanced thermal protection systems also will be necessary for future launch vehicles because they will fly faster through the atmosphere, resulting in higher structural heating than today's vehicles. [2]
Another emerging technology – intelligent vehicle health management systems – could allow the launch vehicle to determine its own health without human inspection. Sensors embedded in the vehicle could send signals to determine if any damage occurs during flight. Upon landing, the vehicle's on-board computer could download the vehicle's health status to a ground controller's laptop computer, recommend specific maintenance points or tell the launch site it's ready for the next launch. [2]
The Advanced Space Transportation Program is developing technologies for air-breathing rocket engines that could help make future space transportation like today's air travel. In late 1996, the Marshall Center began testing these radical rocket engines. Powered by engines that "breathe" oxygen from the air, the spacecraft would be completely reusable, take off and land at airport runways, and be ready to fly again within days.[ citation needed ]
An air-breathing engine – or rocket-based, combined cycle engine – gets its initial take-off power from specially designed rockets, called air-augmented rockets, that boost performance about 15 percent over conventional rockets. When the vehicle's velocity reaches twice the speed of sound, the rockets are turned off and the engine relies totally on oxygen in the atmosphere to burn the fuel. Once the vehicle's speed increases to about 10 times the speed of sound, the engine converts to a conventional rocket-powered system to propel the vehicle into orbit. Testing of the engine continues at General Applied Sciences Laboratory facilities on Long Island, N.Y.[ citation needed ]
Along with air-breathing propulsion, there is also magnetic levitation, highly integrated airframe structures that morph in flight, and intelligent vehicle health management systems are some of the other technologies being considered for a third generation RLV. [1]
The ASTP is also investigating technologies for a fourth generation reusable launch vehicles that could be operational in the 2040 time-frame. The goal is to make space travel safer by a factor of 20,000 and more affordable by a factor of 1,000, compared to present day systems. Routine passenger space travel is envisioned for this fourth generation RLV. [1]
As access to outer space improves and becomes routine, this will enable new markets to open up. This includes space-based adventure tourism and travel, along with space-based business parks. Other types of benefits to commerce and the global population includes solar electric power beamed from space to Earth, space-based hospitals for treatment of chronic pain and disabilities, mining asteroids for high-value minerals, and a worldwide, two-hour express package delivery system. [1]
The ASTP is developing technologies to decrease the trip times and reduce the weight of the propulsion systems required for planetary missions - including riskier missions to the edge of the Solar System and beyond. Some of the technologies under development to accomplish these goals are electrodynamic tethers, solar sails, aeroassist and high-power electric propulsion (ion thruster) are just a few of the technologies being developed to achieve the goals. [1]
The ASTP is also conducting fundamental research on the cutting edge of modern science and engineering, including fission, fusion and antimatter propulsion, and breakthrough physics theories that might enable thrusting against space-time itself and faster-than-light travel. [1]
The ASTP leads a team of NASA centers, US Government agencies, industry and academia focused on products and developing a variety of propulsion and vehicle technologies. Technology development is concentrated in the areas of hypersonic transportation, travel beyond low Earth orbit, and advanced concepts research. [1]
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
A single-stage-to-orbit (SSTO) vehicle reaches orbit from the surface of a body using only propellants and fluids and without expending tanks, engines, or other major hardware. The term exclusively refers to reusable vehicles. To date, no Earth-launched SSTO launch vehicles have ever been flown; orbital launches from Earth have been performed by either fully or partially expendable multi-stage rockets.
An expendable launch system is a launch vehicle that can be launched only once, after which its components are either destroyed during reentry or discarded in space. ELVs typically consist of several rocket stages that are discarded sequentially as their fuel is exhausted and the vehicle gains altitude and speed. As of 2024, less and less satellites and human spacecraft are launched on ELVs in favor of reusable launch vehicles. However, there are many instances where a ELV may still have a compelling use case over a reusable vehicle. ELVs are simpler in design than reusable launch systems and therefore may have a lower production cost. Furthermore, an ELV can use its entire fuel supply to accelerate its payload, offering greater payloads. ELVs are proven technology in widespread use for many decades.
Spaceflight is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflight operate either by telerobotic or autonomous control. The more complex human spaceflight has been pursued soon after the first orbital satellites and has reached the Moon and permanent human presence in space around Earth, particularly with the use of space stations. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs. Other current spaceflight are conducted to the International Space Station and to China's Tiangong Space Station.
The aerospike engine is a type of rocket engine that maintains its aerodynamic efficiency across a wide range of altitudes. It belongs to the class of altitude compensating nozzle engines. Aerospike engines were proposed for many single-stage-to-orbit (SSTO) designs. They were a contender for the Space Shuttle main engine. However, as of 2023 no such engine was in commercial production, although some large-scale aerospikes were in testing phases.
Human spaceflight programs have been conducted, started, or planned by multiple countries and companies. Until the 21st century, human spaceflight programs were sponsored exclusively by governments, through either the military or civilian space agencies. With the launch of the privately funded SpaceShipOne in 2004, a new category of human spaceflight programs – commercial human spaceflight – arrived. By the end of 2022, three countries and one private company (SpaceX) had successfully launched humans to Earth orbit, and two private companies had launched humans on a suborbital trajectory.
A reusable launch vehicle has parts that can be recovered and reflown, while carrying payloads from the surface to outer space. Rocket stages are the most common launch vehicle parts aimed for reuse. Smaller parts such as rocket engines and boosters can also be reused, though reusable spacecraft may be launched on top of an expendable launch vehicle. Reusable launch vehicles do not need to make these parts for each launch, therefore reducing its launch cost significantly. However, these benefits are diminished by the cost of recovery and refurbishment.
A spaceplane is a vehicle that can fly and glide like an aircraft in Earth's atmosphere and maneuver like a spacecraft in outer space. To do so, spaceplanes must incorporate features of both aircraft and spacecraft. Orbital spaceplanes tend to be more similar to conventional spacecraft, while sub-orbital spaceplanes tend to be more similar to fixed-wing aircraft. All spaceplanes to date have been rocket-powered for takeoff and climb, but have then landed as unpowered gliders.
The Saturn IB(also known as the uprated Saturn I) was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage, with the S-IVB. The S-IB first stage also increased the S-I baseline's thrust from 1,500,000 pounds-force (6,700,000 N) to 1,600,000 pounds-force (7,100,000 N) and propellant load by 3.1%. This increased the Saturn I's low Earth orbit payload capability from 20,000 pounds (9,100 kg) to 46,000 pounds (21,000 kg), enough for early flight tests of a half-fueled Apollo command and service module (CSM) or a fully fueled Apollo Lunar Module (LM), before the larger Saturn V needed for lunar flight was ready.
The NASA X-43 was an experimental unmanned hypersonic aircraft with multiple planned scale variations meant to test various aspects of hypersonic flight. It was part of the X-plane series and specifically of NASA's Hyper-X program developed in the late 1990s. It set several airspeed records for jet aircraft. The X-43 is the fastest jet-powered aircraft on record at approximately Mach 9.6.
The Lockheed Martin X-33 was a proposed uncrewed, sub-scale technology demonstrator suborbital spaceplane that was developed for a period in the 1990s. The X-33 was a technology demonstrator for the VentureStar orbital spaceplane, which was planned to be a next-generation, commercially operated reusable launch vehicle. The X-33 would flight-test a range of technologies that NASA believed it needed for single-stage-to-orbit reusable launch vehicles, such as metallic thermal protection systems, composite cryogenic fuel tanks for liquid hydrogen, the aerospike engine, autonomous (uncrewed) flight control, rapid flight turn-around times through streamlined operations, and its lifting body aerodynamics.
The DC-X, short for Delta Clipper or Delta Clipper Experimental, was an uncrewed prototype of a reusable single-stage-to-orbit launch vehicle built by McDonnell Douglas in conjunction with the United States Department of Defense's Strategic Defense Initiative Organization (SDIO) from 1991 to 1993. Starting 1994 until 1995, testing continued through funding of the US civil space agency NASA. In 1996, the DC-X technology was completely transferred to NASA, which upgraded the design for improved performance to create the DC-XA. After a test flight of DC-XA in 1996 resulted in a fire, the project was canceled. Despite its cancellation, the program inspired later reusable launch systems. Michael D. Griffin has since praised the program as "government R&D at its finest."
The Boeing X-37, also known as the Orbital Test Vehicle (OTV), is a reusable robotic spacecraft. It is boosted into space by a launch vehicle, then re-enters Earth's atmosphere and lands as a spaceplane. The X-37 is operated by the Department of the Air Force Rapid Capabilities Office, in collaboration with United States Space Force, for orbital spaceflight missions intended to demonstrate reusable space technologies. It is a 120-percent-scaled derivative of the earlier Boeing X-40. The X-37 began as a NASA project in 1999, before being transferred to the United States Department of Defense in 2004. Until 2019, the program was managed by Air Force Space Command.
Scramjet programs refers to research and testing programs for the development of supersonic combustion ramjets, known as scramjets. This list provides a short overview of national and international collaborations, and civilian and military programs. The USA, Russia, India, and China (2014), have succeeded at developing scramjet technologies.
The Space Launch Initiative (SLI) was a NASA and U.S. Department of Defense joint research and technology project to determine the requirements to meet all the nation's hypersonics, space launch and space technology needs. It was also known as the second generation Reusable Launch Vehicle program, after the failure of the first. The program began with the award of RLV study contracts in 2000.
Air-launch-to-orbit (ALTO) is the method of launching smaller rockets at altitude from a heavier conventional horizontal-takeoff aircraft, to carry satellites to low Earth orbit. It is a follow-on development of air launches of experimental aircraft that began in the late 1940s. This method, when employed for orbital payload insertion, presents significant advantages over conventional vertical rocket launches, particularly because of the reduced mass, thrust, cost of the rocket, geographical factors, and natural disasters.
A rocket sled launch, also known as ground-based launch assist, catapult launch assist, and sky-ramp launch, is a proposed method for launching space vehicles. With this concept the launch vehicle is supported by an eastward pointing rail or maglev track that goes up the side of a mountain while an externally applied force is used to accelerate the launch vehicle to a given velocity. Using an externally applied force for the initial acceleration reduces the propellant the launch vehicle needs to carry to reach orbit. This allows the launch vehicle to carry a larger payload and reduces the cost of getting to orbit. When the amount of velocity added to the launch vehicle by the ground accelerator becomes great enough, single-stage-to-orbit flight with a reusable launch vehicle becomes possible.
Reusable Launch Vehicle–Technology Demonstration Programme is a series of technology demonstration missions that has been conceived by the Indian Space Research Organisation (ISRO) as a first step towards realising a Two Stage To Orbit (TSTO) re-usable launch vehicle, in which the second stage is a spaceplane.
SpaceX manufactures launch vehicles to operate its launch provider services and to execute its various exploration goals. SpaceX currently manufactures and operates the Falcon 9 Block 5 family of medium-lift launch vehicles and the Falcon Heavy family of heavy-lift launch vehicles – both of which are powered by SpaceX Merlin engines and employ VTVL technologies to reuse the first stage. As of 2024, the company is also developing the fully reusable Starship launch system, which will replace the Falcon 9 and Falcon Heavy.
The DARPA XS-1 was an experimental spaceplane/booster with the planned capability to deliver small satellites into orbit for the U.S. Military. It was reported to be designed to be reusable as frequently as once a day, with a stated goal of doing so for 10 days straight. The XS-1 was intended to directly replace the first stage of a multistage rocket by taking off vertically and flying to hypersonic speed and high suborbital altitude, enabling one or more expendable upper stages to separate and deploy a payload into low Earth orbit. The XS-1 would then return to Earth, where it could ostensibly be serviced fast enough to repeat the process at least once every 24 hours.
This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration .
