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Crew Return Vehicle
The Crew Return Vehicle (CRV), sometimes referred to as the Assured Crew Return Vehicle (ACRV), was a proposed dedicated lifeboat or escape module for the International Space Station (ISS). A number of different vehicles and designs were considered over two decades – with several flying as developmental test prototypes – but none became operational. Since the arrival of the first permanent crew to the ISS in 2000, the emergency return capability has been fulfilled by Soyuz spacecraft and, more recently, SpaceX's Crew Dragon – each rotated every 6 months.
In the original space station design, emergencies were intended to be dealt with by having a "safe area" on the station that the crew could evacuate to, pending a rescue from a U.S. Space Shuttle. However, the 1986 Space Shuttle Challenger disaster and the subsequent grounding of the shuttle fleet caused station planners to rethink this concept. Planners foresaw the need for a CRV to address three specific scenarios:
The ISS is equipped with a Health Maintenance Facility (HMF) to handle a certain level of medical situations, which are broken into three main classifications:
However, the HMF is not designed to have general surgical capability, so a means of evacuating a crew member in case of a medical situation that is beyond the HMF's capabilities is essential.[citation needed]
A number of studies have attempted to assess the medical risks for long-term space station habitation, but the results are inconclusive, as epidemiological data is lacking. It is, however, understood that longer periods in space increase the risk of serious problems. The closest estimates show an illness/injury rate of 1:3 per year, with 1% estimated to require emergency evacuation by means of a CRV. For an eight-person ISS crew, this results in an expected need for a CRV flight once every 4 to 12 years. These estimates have been partially corroborated by experiences on board the Soviet Union's Mir space station. In the 1980s, the Soviets had at least three incidents where cosmonauts had to be returned under urgent medical conditions.
Because of its potential use as a medical evacuation method, the CRV design was required to address a number of issues that are not factors for a standard crewed space vehicle. Foremost of these are the g-loadings as influenced by reentry profiles and deceleration/landing methods upon patients with hemorrhagic shock issues. Patient security issues are more critical for injured astronauts than for uninjured personnel. Additionally, depending on the nature of the injury, it may be unlikely that the patient could be placed in an environmentally contained space suit or minicapsule, therefore the CRV needs to have the capability to provide a "shirt sleeve" environment. The ability to address air purity issues is included in this requirement, as air purity is especially critical in medical as well as toxic exposure situations.
Dr. Wernher von Braun first brought up the concept of space lifeboats in a 1966 article, and then later NASA planners developed a number of early concepts for a space station lifeboat:
The HL-20 Crew Rescue Vehicle was based on the Personnel Launch System (PLS) concept being developed by NASA as an outgrowth of earlier lifting body research. In October 1989, Rockwell International (Space Systems Division) began a year-long contracted effort managed by Langley Research Center to perform an in-depth study of PLS design and operations with the HL-20 concept as a baseline for the study. In October 1991, the Lockheed Advanced Development Company (better known as the Skunk Works) began a study to determine the feasibility of developing a prototype and operational system. A cooperative agreement between NASA, North Carolina State University and North Carolina A&T University led to the construction of a full-scale model of the HL-20 PLS for further human factors research on this concept. Of all the options, a lifting body presents the most ideal medical environment in terms of controlled environment as well as low g-loading during reentry and landing. However, the price tag for the HL-20 project was US$2 billion, and Congress cut the program from NASA's budget in 1990.
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Crew Return Vehicle AI simulator
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Crew Return Vehicle
The Crew Return Vehicle (CRV), sometimes referred to as the Assured Crew Return Vehicle (ACRV), was a proposed dedicated lifeboat or escape module for the International Space Station (ISS). A number of different vehicles and designs were considered over two decades – with several flying as developmental test prototypes – but none became operational. Since the arrival of the first permanent crew to the ISS in 2000, the emergency return capability has been fulfilled by Soyuz spacecraft and, more recently, SpaceX's Crew Dragon – each rotated every 6 months.
In the original space station design, emergencies were intended to be dealt with by having a "safe area" on the station that the crew could evacuate to, pending a rescue from a U.S. Space Shuttle. However, the 1986 Space Shuttle Challenger disaster and the subsequent grounding of the shuttle fleet caused station planners to rethink this concept. Planners foresaw the need for a CRV to address three specific scenarios:
The ISS is equipped with a Health Maintenance Facility (HMF) to handle a certain level of medical situations, which are broken into three main classifications:
However, the HMF is not designed to have general surgical capability, so a means of evacuating a crew member in case of a medical situation that is beyond the HMF's capabilities is essential.[citation needed]
A number of studies have attempted to assess the medical risks for long-term space station habitation, but the results are inconclusive, as epidemiological data is lacking. It is, however, understood that longer periods in space increase the risk of serious problems. The closest estimates show an illness/injury rate of 1:3 per year, with 1% estimated to require emergency evacuation by means of a CRV. For an eight-person ISS crew, this results in an expected need for a CRV flight once every 4 to 12 years. These estimates have been partially corroborated by experiences on board the Soviet Union's Mir space station. In the 1980s, the Soviets had at least three incidents where cosmonauts had to be returned under urgent medical conditions.
Because of its potential use as a medical evacuation method, the CRV design was required to address a number of issues that are not factors for a standard crewed space vehicle. Foremost of these are the g-loadings as influenced by reentry profiles and deceleration/landing methods upon patients with hemorrhagic shock issues. Patient security issues are more critical for injured astronauts than for uninjured personnel. Additionally, depending on the nature of the injury, it may be unlikely that the patient could be placed in an environmentally contained space suit or minicapsule, therefore the CRV needs to have the capability to provide a "shirt sleeve" environment. The ability to address air purity issues is included in this requirement, as air purity is especially critical in medical as well as toxic exposure situations.
Dr. Wernher von Braun first brought up the concept of space lifeboats in a 1966 article, and then later NASA planners developed a number of early concepts for a space station lifeboat:
The HL-20 Crew Rescue Vehicle was based on the Personnel Launch System (PLS) concept being developed by NASA as an outgrowth of earlier lifting body research. In October 1989, Rockwell International (Space Systems Division) began a year-long contracted effort managed by Langley Research Center to perform an in-depth study of PLS design and operations with the HL-20 concept as a baseline for the study. In October 1991, the Lockheed Advanced Development Company (better known as the Skunk Works) began a study to determine the feasibility of developing a prototype and operational system. A cooperative agreement between NASA, North Carolina State University and North Carolina A&T University led to the construction of a full-scale model of the HL-20 PLS for further human factors research on this concept. Of all the options, a lifting body presents the most ideal medical environment in terms of controlled environment as well as low g-loading during reentry and landing. However, the price tag for the HL-20 project was US$2 billion, and Congress cut the program from NASA's budget in 1990.